Carabidae diversity along an altitudinal gradient in a Peruvian cloud forest (Coleoptera).

PubMed

Maveety, Sarah A; Browne, Robert A; Erwin, Terry L

2011-01-01

Carabid beetles were sampled at five sites, ranging from 1500 m to 3400 m, along a 15 km transect in the cloud forest of Manu National Park, Perú. Seasonal collections during a one year period yielded 77 morphospecies, of which 60% are projected to be undescribed species. There was a significant negative correlation between species richness and altitude, with the number of carabid species declining at the rate of one species for each 100 m increase in altitude. The majority of species (70.1 %) were restricted to only one altitudinal site and no species was found at more than three of the five altitudinal sites. Only one genus, Pelmatellus (Tribe Harpalini), was found at all five sites. Active (hand) collections yielded approximately twice as many species per individuals collected than passive (pitfall trap) collections. This study is the first systematic sampling ofcarabid beetles of a high altitude gradient in the cloud forests of southeastern Perú and supports the need to conserve the zone of extremely high biodiversity present on the eastern slopes of the Peruvian Andes.

Carabidae diversity along an altitudinal gradient in a Peruvian cloud forest (Coleoptera)

PubMed Central

Maveety, Sarah A.; Browne, Robert A.; Erwin, Terry L.

2011-01-01

Abstract Carabid beetles were sampled at five sites, ranging from 1500 m to 3400 m, along a 15 km transect in the cloud forest of Manu National Park, Perú. Seasonal collections during a one year period yielded 77 morphospecies, of which 60% are projected to be undescribed species. There was a significant negative correlation between species richness and altitude, with the number of carabid species declining at the rate of one species for each 100 m increase in altitude. The majority of species (70.1 %) were restricted to only one altitudinal site and no species was found at more than three of the five altitudinal sites. Only one genus, Pelmatellus (Tribe Harpalini), was found at all five sites. Active (hand) collections yielded approximately twice as many species per individuals collected than passive (pitfall trap) collections. This study is the first systematic sampling ofcarabid beetles of a high altitude gradient in the cloud forests of southeastern Perú and supports the need to conserve the zone of extremely high biodiversity present on the eastern slopes of the Peruvian Andes. PMID:22371680

Thermal Tolerance in Anuran Embryos with Different Reproductive Modes: Relationship to Altitude

PubMed Central

Lynch, John D.

2013-01-01

Anurans are ectothermic animals very sensitive to temperature, mainly during the embryonic stage. In addition, environmental temperature decreases with altitude, and the amphibian fauna changes. Therefore, we studied the relationship between the embryonic thermal tolerances of twelve species of anurans and the temperatures of their microhabitat along an altitudinal gradient from 430 m to 2600 m. We hypothesized that there is a strong thermal adjustment of embryos to their microhabitat and, consequently, that temperature could be a limiting factor of altitudinal distribution of the anurans. We also compared the embryonic thermal tolerances according to six postulated reproductive modes of the study species. We found a significant relationship between the maximum and minimum thermal tolerances of the anuran embryos and the maximum and minimum temperatures of their microhabitat and altitudinal distribution. We also found a wide range of embryonic thermal tolerances for aquatic breeding species and a narrower range for terrestrial breeding species. Particularly, embryos of direct development species were the most sensitive to temperature. These results show the strong thermal adjustment of anuran embryos to their microhabitat and elevation and do not reject the hypothesis that temperature can be a limiting factor of their altitudinal distribution. PMID:23766678

Contrasting growth forecasts across the geographical range of Scots pine due to altitudinal and latitudinal differences in climatic sensitivity.

PubMed

Matías, Luis; Linares, Juan C; Sánchez-Miranda, Ángela; Jump, Alistair S

2017-10-01

Ongoing changes in global climate are altering ecological conditions for many species. The consequences of such changes are typically most evident at the edge of a species' geographical distribution, where differences in growth or population dynamics may result in range expansions or contractions. Understanding population responses to different climatic drivers along wide latitudinal and altitudinal gradients is necessary in order to gain a better understanding of plant responses to ongoing increases in global temperature and drought severity. We selected Scots pine (Pinus sylvestris L.) as a model species to explore growth responses to climatic variability (seasonal temperature and precipitation) over the last century through dendrochronological methods. We developed linear models based on age, climate and previous growth to forecast growth trends up to year 2100 using climatic predictions. Populations were located at the treeline across a latitudinal gradient covering the northern, central and southernmost populations and across an altitudinal gradient at the southern edge of the distribution (treeline, medium and lower elevations). Radial growth was maximal at medium altitude and treeline of the southernmost populations. Temperature was the main factor controlling growth variability along the gradients, although the timing and strength of climatic variables affecting growth shifted with latitude and altitude. Predictive models forecast a general increase in Scots pine growth at treeline across the latitudinal distribution, with southern populations increasing growth up to year 2050, when it stabilizes. The highest responsiveness appeared at central latitude, and moderate growth increase is projected at the northern limit. Contrastingly, the model forecasted growth declines at lowland-southern populations, suggesting an upslope range displacement over the coming decades. Our results give insight into the geographical responses of tree species to climate change and demonstrate the importance of incorporating biogeographical variability into predictive models for an accurate prediction of species dynamics as climate changes. © 2017 John Wiley & Sons Ltd.

Intra- and interspecific tree growth across a long altitudinal gradient in the Peruvian Andes.

PubMed

Rapp, Joshua M; Silman, Miles R; Clark, James S; Girardin, Cecile A J; Galiano, Darcy; Tito, Richard

2012-09-01

Tree growth response across environmental gradients is fundamental to understanding species distributional ecology and forest ecosystem ecology and to predict future ecosystem services. Cross-sectional patterns of ecosystem properties with respect to climatic gradients are often used to predict ecosystem responses to global change. Across sites in the tropics, primary productivity increases with temperature, suggesting that forest ecosystems will become more productive as temperature rises. However, this trend is confounded with a shift in species composition and so may not reflect the response of in situ forests to warming. In this study, we simultaneously studied tree diameter growth across the altitudinal ranges of species within a single genus across a geographically compact temperature gradient, to separate the direct effect of temperature on tree growth from that of species compositional turnover. Using a Bayesian state space modeling framework we combined data from repeated diameter censuses and dendrometer measurements from across a 1700-m altitudinal gradient collected over six years on over 2400 trees in Weinmannia, a dominant and widespread genus of cloud forest trees in the Andes. Within species, growth showed no consistent trend with altitude, but higher-elevation species had lower growth rates than lower-elevation species, suggesting that species turnover is largely responsible for the positive correlation between productivity and temperature in tropical forests. Our results may indicate a significant difference in how low- and high-latitude forests will respond to climate change, since temperate and boreal tree species are consistently observed to have a positive relationship between growth and temperature. If our results hold for other tropical species, a positive response in ecosystem productivity to increasing temperatures in the Andes will depend on the altitudinal migration of tree species. The rapid pace of climate change, and slow observed rates of migration, suggest a slow, or even initially negative response of ecosystem productivity to warming. Finally, this study shows how the observed scale of biological organization can affect conclusions drawn from studies of ecological phenomena across environmental gradients, and calls into question the common practice in tropical ecology of lumping species at higher taxonomic levels.

Temperature sensitivity and enzymatic mechanisms of soil organic matter decomposition along an altitudinal gradient on Mount Kilimanjaro

NASA Astrophysics Data System (ADS)

Blagodatskaya, Evgenia; Blagodatsky, Sergey; Khomyakov, Nikita; Myachina, Olga; Kuzyakov, Yakov

2016-02-01

Short-term acceleration of soil organic matter decomposition by increasing temperature conflicts with the thermal adaptation observed in long-term studies. Here we used the altitudinal gradient on Mt. Kilimanjaro to demonstrate the mechanisms of thermal adaptation of extra- and intracellular enzymes that hydrolyze cellulose, chitin and phytate and oxidize monomers (14C-glucose) in warm- and cold-climate soils. We revealed that no response of decomposition rate to temperature occurs because of a cancelling effect consisting in an increase in half-saturation constants (Km), which counteracts the increase in maximal reaction rates (Vmax with temperature). We used the parameters of enzyme kinetics to predict thresholds of substrate concentration (Scrit) below which decomposition rates will be insensitive to global warming. Increasing values of Scrit, and hence stronger canceling effects with increasing altitude on Mt. Kilimanjaro, explained the thermal adaptation of polymer decomposition. The reduction of the temperature sensitivity of Vmax along the altitudinal gradient contributed to thermal adaptation of both polymer and monomer degradation. Extrapolating the altitudinal gradient to the large-scale latitudinal gradient, these results show that the soils of cold climates with stronger and more frequent temperature variation are less sensitive to global warming than soils adapted to high temperatures.

Adaptation of sugar maple populations along altitudinal gradients: photosynthesis, respiration, and specific leaf weight

Treesearch

F. Thomas Ledig; Donald R. Korbobo

1983-01-01

Sugar maple seeds were collected from populations spaced along two altitudinal gradients in the White Mountains of New Hampshire. When grown in a uniform environment, progeny of stands less than 0.8 km apart differed significantly in photosynthesis, respiration, and leaf characteristics, despite a lack of physical barriers to gene migration. Sugar maple is a long-lived...

Plastic Responses Contribute to Explaining Altitudinal and Temporal Variation in Potential Flower Longevity in High Andean Rhodolirion montanum.

PubMed

Pacheco, Diego Andrés; Dudley, Leah S; Cabezas, Josefina; Cavieres, Lohengrin A; Arroyo, Mary T K

2016-01-01

The tendency for flower longevity to increase with altitude is believed by many alpine ecologists to play an important role in compensating for low pollination rates at high altitudes due to cold and variable weather conditions. However, current studies documenting an altitudinal increase in flower longevity in the alpine habitat derive principally from studies on open-pollinated flowers where lower pollinator visitation rates at higher altitudes will tend to lead to flower senescence later in the life-span of a flower in comparison with lower altitudes, and thus could confound the real altitudinal pattern in a species´ potential flower longevity. In a two-year study we tested the hypothesis that a plastic effect of temperature on flower longevity could contribute to an altitudinal increase in potential flower longevity measured in pollinator-excluded flowers in high Andean Rhodolirium montanum Phil. (Amaryllidaceae). Using supplemental warming we investigated whether temperature around flowers plastically affects potential flower longevity. We determined tightly temperature-controlled potential flower longevity and flower height for natural populations on three alpine sites spread over an altitudinal transect from 2350 and 3075 m a.s.l. An experimental increase of 3.1°C around flowers significantly decreased flower longevity indicating a plastic response of flowers to temperature. Flower height in natural populations decreased significantly with altitude. Although temperature negatively affects flower longevity under experimental conditions, we found no evidence that temperature around flowers explains site variation in flower longevity over the altitudinal gradient. In a wetter year, despite a 3.5°C temperature difference around flowers at the extremes of the altitudinal range, flower longevity showed no increase with altitude. However, in a drier year, flower longevity increased significantly with altitude. The emerging picture suggests an increase in flower longevity along the altitudinal gradient is less common for potential flower longevity than for open-pollination flower longevity. Independently of any selection that may occur on potential longevity, plastic responses of flowers to environmental conditions are likely to contribute to altitudinal variation in flower longevity, especially in dry alpine areas. Such plastic responses could push flowers of alpine species towards shorter life-lengths under climate change, with uncertain consequences for successful pollination and plant fitness in a warming world.

Plastic Responses Contribute to Explaining Altitudinal and Temporal Variation in Potential Flower Longevity in High Andean Rhodolirion montanum

PubMed Central

Cavieres, Lohengrin A.

2016-01-01

The tendency for flower longevity to increase with altitude is believed by many alpine ecologists to play an important role in compensating for low pollination rates at high altitudes due to cold and variable weather conditions. However, current studies documenting an altitudinal increase in flower longevity in the alpine habitat derive principally from studies on open-pollinated flowers where lower pollinator visitation rates at higher altitudes will tend to lead to flower senescence later in the life-span of a flower in comparison with lower altitudes, and thus could confound the real altitudinal pattern in a species´ potential flower longevity. In a two-year study we tested the hypothesis that a plastic effect of temperature on flower longevity could contribute to an altitudinal increase in potential flower longevity measured in pollinator-excluded flowers in high Andean Rhodolirium montanum Phil. (Amaryllidaceae). Using supplemental warming we investigated whether temperature around flowers plastically affects potential flower longevity. We determined tightly temperature-controlled potential flower longevity and flower height for natural populations on three alpine sites spread over an altitudinal transect from 2350 and 3075 m a.s.l. An experimental increase of 3.1°C around flowers significantly decreased flower longevity indicating a plastic response of flowers to temperature. Flower height in natural populations decreased significantly with altitude. Although temperature negatively affects flower longevity under experimental conditions, we found no evidence that temperature around flowers explains site variation in flower longevity over the altitudinal gradient. In a wetter year, despite a 3.5°C temperature difference around flowers at the extremes of the altitudinal range, flower longevity showed no increase with altitude. However, in a drier year, flower longevity increased significantly with altitude. The emerging picture suggests an increase in flower longevity along the altitudinal gradient is less common for potential flower longevity than for open-pollination flower longevity. Independently of any selection that may occur on potential longevity, plastic responses of flowers to environmental conditions are likely to contribute to altitudinal variation in flower longevity, especially in dry alpine areas. Such plastic responses could push flowers of alpine species towards shorter life-lengths under climate change, with uncertain consequences for successful pollination and plant fitness in a warming world. PMID:27861586

Soil carbon stocks along an altitudinal gradient in different land-use categories in Lesser Himalayan foothills of Kashmir

NASA Astrophysics Data System (ADS)

Shaheen, H.; Saeed, Y.; Abbasi, M. K.; Khaliq, A.

2017-04-01

The carbon sequestration potential of soils plays an important role in mitigating the effect of climate change, because soils serve as sinks for atmospheric carbon. The present study was conducted to estimate the carbon stocks and their variation with altitudinal gradient in the Lesser Himalayan foothills of Kashmir. The carbon stocks were estimated in different land use categories, namely: closed canopy forests, open forests, disturbed forests, and agricultural lands within the altitudinal range from 900 to 2500 m. The soil carbon content was determined by the Walkley-Black titration method. The average soil carbon stock was found to be 2.59 kg m-2. The average soil carbon stocks in closed canopy forests, open forests, and disturbed forests were 3.39, 2.06, and 2.86 kg m-2, respectively. The average soil carbon stock in the agricultural soils was 2.03 kg m-2. The carbon stocks showed a significant decreasing trend with the altitudinal gradient with maximum values of 4.13 kg m-2 at 900-1200 m a.s.l. and minimum value of 1.55 kg m-2 at 2100-2400 m a.s.l. The agricultural soil showed the least carbon content values indicating negative impacts of soil plowing, overgrazing, and soil degradation. Lower carbon values at higher altitudes attest to the immature character of forest stands, as well as to degradation due to immense fuel wood extraction, timber extraction, and harsh climatic conditions. The study indicates that immediate attention is required for the conservation of rapidly declining carbon stocks in agricultural soils, as well as in the soils of higher altitudes.

Altitudinal patterns of plant diversity on the Jade Dragon Snow Mountain, southwestern China.

PubMed

Xu, Xiang; Zhang, Huayong; Tian, Wang; Zeng, Xiaoqiang; Huang, Hai

2016-01-01

Understanding altitudinal patterns of biological diversity and their underlying mechanisms is critically important for biodiversity conservation in mountainous regions. The contribution of area to plant diversity patterns is widely acknowledged and may mask the effects of other determinant factors. In this context, it is important to examine altitudinal patterns of corrected taxon richness by eliminating the area effect. Here we adopt two methods to correct observed taxon richness: a power-law relationship between richness and area, hereafter "method 1"; and richness counted in equal-area altitudinal bands, hereafter "method 2". We compare these two methods on the Jade Dragon Snow Mountain, which is the nearest large-scale altitudinal gradient to the Equator in the Northern Hemisphere. We find that seed plant species richness, genus richness, family richness, and species richness of trees, shrubs, herbs and Groups I-III (species with elevational range size <150, between 150 and 500, and >500 m, respectively) display distinct hump-shaped patterns along the equal-elevation altitudinal gradient. The corrected taxon richness based on method 2 (TRcor2) also shows hump-shaped patterns for all plant groups, while the one based on method 1 (TRcor1) does not. As for the abiotic factors influencing the patterns, mean annual temperature, mean annual precipitation, and mid-domain effect explain a larger part of the variation in TRcor2 than in TRcor1. In conclusion, for biodiversity patterns on the Jade Dragon Snow Mountain, method 2 preserves the significant influences of abiotic factors to the greatest degree while eliminating the area effect. Our results thus reveal that although the classical method 1 has earned more attention and approval in previous research, method 2 can perform better under certain circumstances. We not only confirm the essential contribution of method 1 in community ecology, but also highlight the significant role of method 2 in eliminating the area effect, and call for more application of method 2 in further macroecological studies.

Altitude acts as an environmental filter on phylogenetic composition, traits and diversity in bee communities.

PubMed

Hoiss, Bernhard; Krauss, Jochen; Potts, Simon G; Roberts, Stuart; Steffan-Dewenter, Ingolf

2012-11-07

Knowledge about the phylogeny and ecology of communities along environmental gradients helps to disentangle the role of competition-driven processes and environmental filtering for community assembly. In this study, we evaluated patterns in species richness, phylogenetic structure and life-history traits of bee communities along altitudinal gradients in the Alps, Germany. We found a linear decline in species richness and abundance but increasing phylogenetic clustering in communities with increasing altitude. The proportion of social- and ground-nesting species, as well as mean body size and altitudinal range of bee communities, increased with increasing altitude, whereas the mean geographical distribution decreased. Our results suggest that community assembly at high altitudes is dominated by environmental filtering effects, whereas the relative importance of competition increases at low altitudes. We conclude that inherent phylogenetic and ecological species attributes at high altitudes pose a threat for less competitive alpine specialists with ongoing climate change.

Altitude acts as an environmental filter on phylogenetic composition, traits and diversity in bee communities

PubMed Central

Hoiss, Bernhard; Krauss, Jochen; Potts, Simon G.; Roberts, Stuart; Steffan-Dewenter, Ingolf

2012-01-01

Knowledge about the phylogeny and ecology of communities along environmental gradients helps to disentangle the role of competition-driven processes and environmental filtering for community assembly. In this study, we evaluated patterns in species richness, phylogenetic structure and life-history traits of bee communities along altitudinal gradients in the Alps, Germany. We found a linear decline in species richness and abundance but increasing phylogenetic clustering in communities with increasing altitude. The proportion of social- and ground-nesting species, as well as mean body size and altitudinal range of bee communities, increased with increasing altitude, whereas the mean geographical distribution decreased. Our results suggest that community assembly at high altitudes is dominated by environmental filtering effects, whereas the relative importance of competition increases at low altitudes. We conclude that inherent phylogenetic and ecological species attributes at high altitudes pose a threat for less competitive alpine specialists with ongoing climate change. PMID:22933374

Anthocyanin Profile in Berries of Wild and Cultivated Vaccinium spp. along Altitudinal Gradients in the Alps.

PubMed

Zoratti, Laura; Jaakola, Laura; Häggman, Hely; Giongo, Lara

2015-10-07

Vaccinium spp. berries provide some of the best natural sources of anthocyanins. In the wild bilberry (Vaccinium myrtillus L.), a clear increasing trend in anthocyanin biosynthesis has been reported toward northern latitudes of Europe, but studies related to altitude have given contradictory results. The present study focused on the anthocyanin composition in wild bilberries and highbush blueberry (Vaccinium corymbosum L. cv. Brigitta Blue) growing along altitudinal gradients in the Alps of northern Italy. Our results indicate an increasing accumulation of anthocyanins in bilberries along an altitudinal gradient of about 650 m. The accumulation was due to a significant increase in delphinidin and malvidin glycosides, whereas the accumulation of cyanidin and peonidin glycosides was not affected by altitude. Seasonal differences, especially temperature, had a major influence on the accumulation of anthocyanins in blueberries.

Toward an integrated view of ionospheric plasma instabilities: Altitudinal transitions and strong gradient case

NASA Astrophysics Data System (ADS)

Makarevich, Roman A.

2016-04-01

A general dispersion relation is derived that integrates the Farley-Buneman, gradient-drift, and current-convective plasma instabilities (FBI, GDI, and CCI) within the same formalism for an arbitrary altitude, wave propagation vector, and background density gradient. The limiting cases of the FBI/GDI in the E region for nearly field-aligned irregularities, GDI/CCI in the main F region at long wavelengths, and GDI at high altitudes are successfully recovered using analytic analysis. Numerical solutions are found for more general representative cases spanning the entire ionosphere. It is demonstrated that the results are consistent with those obtained using a general FBI/GDI/CCI theory developed previously at and near E region altitudes under most conditions. The most significant differences are obtained for strong gradients (scale lengths of 100 m) at high altitudes such as those that may occur during highly structured soft particle precipitation events. It is shown that the strong gradient case is dominated by inertial effects and, for some scales, surprisingly strong additional damping due to higher-order gradient terms. The growth rate behavior is examined with a particular focus on the range of wave propagations with positive growth (instability cone) and its transitions between altitudinal regions. It is shown that these transitions are largely controlled by the plasma density gradients even when FBI is operational.

Altitudinal gradients of generalist and specialist herbivory on three montane Asteraceae

NASA Astrophysics Data System (ADS)

Scheidel, U.; Röhl, S.; Bruelheide, H.

Different functional types of herbivory on three montane Asteraceae were investigated in natural populations in central Germany to test the hypothesis that herbivory is decreasing with altitude. Generalist herbivory was assessed as leaf area loss, mainly caused by slugs, and, in Petasites albus, as rhizome mining by oligophagous insect larvae. Capitules were found to be parasitized by oligophagous insects in Centaurea pseudophrygia and by the specialist fly Tephritis arnicae in Arnica montana. Only the damage to leaves of P. albus showed the hypothesized decrease with increasing altitude. No altitudinal gradient could be found in the leaf and capitule damage to C. pseudophrygia. In A. montana, capitule damage increased with increasing elevation. The data suggest that abundance and activity of generalist herbivores are more affected by climatic conditions along altitudinal gradients than specialist herbivores. In all probability, specialist herbivores depend less on abiotic conditions than on their host's population characteristics, such as host population size.

Living on the edge: adaptive and plastic responses of the tree Nothofagus pumilio to a long-term transplant experiment predict rear-edge upward expansion.

PubMed

Mathiasen, Paula; Premoli, Andrea C

2016-06-01

Current climate change affects the competitive ability and reproductive success of many species, leading to local extinctions, adjustment to novel local conditions by phenotypic plasticity or rapid adaptation, or tracking their optima through range shifts. However, many species have limited ability to expand to suitable areas. Altitudinal gradients, with abrupt changes in abiotic conditions over short distances, represent "natural experiments" for the evaluation of ecological and evolutionary responses under scenarios of climate change. Nothofagus pumilio is the tree species which dominates as pure stands the montane forests of Patagonia. We evaluated the adaptive value of variation in quantitative traits of N. pumilio under contrasting conditions of the altitudinal gradient with a long-term reciprocal transplant experimental design. While high-elevation plants show little response in plant, leaf, and phenological traits to the experimental trials, low-elevation ones show greater plasticity in their responses to changing environments, particularly at high elevation. Our results suggest a relatively reduced potential for evolutionary adaptation of high-elevation genotypes, and a greater evolutionary potential of low-elevation ones. Under global warming scenarios of forest upslope migration, high-elevation variants may be outperformed by low-elevation ones during this process, leading to the local extinction and/or replacement of these genotypes. These results challenge previous models and predictions expected under global warming for altitudinal gradients, on which the leading edge is considered to be the upper treeline forests.

Genetic structure along an altitudinal gradient in Lippia origanoides, a promising aromatic plant species restricted to semiarid areas in northern South America.

PubMed

Vega-Vela, Nelson Enrique; Sánchez, María Isabel Chacón

2012-11-01

The genetic diversity and population structure of Lippia origanoides, a species of the Verbenaceae family that shows promise as a crop plant, was investigated along an altitudinal gradient in the basin of the Chicamocha River in northeastern Colombia. The economic importance of the species, quality of its essential oils, and the fact that it is restricted to some few semiarid areas in northern South America may put the species at risk in a scenario of uncontrolled harvest of natural populations. Lippia origanoides was sampled along an altitudinal gradient from 365 to 2595 m.a.s.l. throughout Chicamocha River Canyon, a semiarid area in northeastern Colombia. Genetic diversity was assessed by means of AFLP markers. The number of AFLP loci (355) and the number of individuals sampled (173) were sufficient to reliably identify four populations at contrasting altitudes (F(ST) = 0.18, P-value < 0.0000), two populations in the lower basin, one population in the medium basin, and one population in the upper basin, with a low level of admixture between them. In average, genetic diversity within populations was relatively high (Ht = 0.32; I = 0.48); nevertheless, diversity was significantly reduced at higher altitude, a pattern that may be consistent with a scenario of range expansion toward higher elevations in an environment with more extreme conditions. The differences in altitude among the basins in the Chicamocha River seem to be relevant in determining the genetic structure of this species.

Diversity of Culturable Soil Micro-fungi along Altitudinal Gradients of Eastern Himalayas

PubMed Central

Devi, Lamabam Sophiya; Khaund, Polashree; Nongkhlaw, Fenella M. W.

2012-01-01

Very few studies have addressed the phylogenetic diversity of fungi from Northeast India under the Eastern Himalayan range. In the present study, an attempt has been made to study the phylogenetic diversity of culturable soil fungi along the altitudinal gradients of eastern Himalayas. Soil samples from 24 m above sea level to 2,000 m above sea level altitudes of North-East India were collected to investigate soil micro-fungal community structure and diversity. Molecular characterization of the isolates was done by PCR amplification of 18S rDNA using universal primers. Phylogenetic analysis using BLAST revealed variation in the distribution and richness of different fungal biodiversity over a wide range of altitudes. A total of 107 isolates were characterized belonging to the phyla Ascomycota and Zygomycota, corresponding to seven orders (Eurotiales, Hypocreales, Calosphaeriales, Capnodiales, Pleosporales, Mucorales, and Mortierellales) and Incertae sedis. The characterized isolates were analysed for richness, evenness and diversity indices. Fungal diversity had significant correlation with soil physico-chemical parameters and the altitude. Eurotiales and Hypocreales were most diverse and abundant group of fungi along the entire altitudinal stretch. Species of Penicillium (D = 1.44) and Aspergillus (D = 1.288) were found to have highest diversity index followed by Talaromyces (D = 1.26) and Fusarium (D = 1.26). Fungal distribution showed negative correlation with altitude and soil moisture content. Soil temperature, pH, humidity and ambient temperature showed positive correlation with fungal distribution. PMID:23115506

Altitudinal Patterns of Species Diversity and Phylogenetic Diversity across Temperate Mountain Forests of Northern China.

PubMed

Zhang, Wenxin; Huang, Dizhou; Wang, Renqing; Liu, Jian; Du, Ning

2016-01-01

The spatial patterns of biodiversity and their underlying mechanisms have been an active area of research for a long time. In this study, a total of 63 samples (20m × 30m) were systematically established along elevation gradients on Mount Tai and Mount Lao, China. We explored altitudinal patterns of plant diversity in the two mountain systems. In order to understand the mechanisms driving current diversity patterns, we used phylogenetic approaches to detect the spatial patterns of phylogenetic diversity and phylogenetic structure along two elevation gradients. We found that total species richness had a monotonically decreasing pattern and tree richness had a unimodal pattern along the elevation gradients in the two study areas. However, altitudinal patterns in shrub richness and herbs richness were not consistent on the two mountains. At low elevation, anthropogenic disturbances contributed to the increase of plant diversity, especially for shrubs and herbs in understory layers, which are more sensitive to changes in microenvironment. The phylogenetic structure of plant communities exhibited an inverted hump-shaped pattern along the elevation gradient on Mount Tai, which demonstrates that environmental filtering is the main driver of plant community assembly at high and low elevations and inter-specific competition may be the main driver of plant community assembly in the middle elevations. However, the phylogenetic structure of plant communities did not display a clear pattern on Mount Lao where the climate is milder. Phylogenetic beta diversity and species beta diversity consistently increased with increasing altitudinal divergence in the two study areas. However, the altitudinal patterns of species richness did not completely mirror phylogenetic diversity patterns. Conservation areas should be selected taking into consideration the preservation of high species richness, while maximizing phylogenetic diversity to improve the potential for diversification in the future.

Changes in richness and community composition of ectomycorrhizal fungi among altitudinal vegetation types on Mount Kinabalu in Borneo.

PubMed

Geml, József; Morgado, Luis N; Semenova-Nelsen, Tatiana A; Schilthuizen, Menno

2017-07-01

The distribution patterns of tropical ectomycorrhizal (ECM) fungi along altitudinal gradients remain largely unknown. Furthermore, despite being an iconic site for biodiversity research, virtually nothing is known about the diversity and spatial patterns of fungi on Mt Kinabalu and neighbouring mountain ranges. We carried out deep DNA sequencing of soil samples collected between 425 and 4000 m above sea level to compare richness and community composition of ECM fungi among altitudinal forest types in Borneo. In addition, we tested whether the observed patterns are driven by habitat or by geometric effect of overlapping ranges of species (mid-domain effect). Community composition of ECM fungi was strongly correlated with elevation. In most genera, richness peaked in the mid-elevation montane forest zone, with the exception of tomentelloid fungi, which showed monotonal decrease in richness with increasing altitude. Richness in lower-mid- and mid-elevations was significantly greater than predicted under the mid-domain effect model. We provide the first insight into the composition of ECM fungal communities and their strong altitudinal turnover in Borneo. The high richness and restricted distribution of many ECM fungi in the montane forests suggest that mid-elevation peak richness is primarily driven by environmental characteristics of this habitat and not by the mid-domain effect. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Variation of arbuscular mycorrhizal fungal communities along an altitudinal gradient in rupestrian grasslands in Brazil.

PubMed

Coutinho, Etiene Silva; Fernandes, G Wilson; Berbara, Ricardo Luís Louro; Valério, Henrique Maia; Goto, Bruno Tomio

2015-11-01

Variation in arbuscular mycorrhizal fungi (AMF) communities is described for the first time in rupestrian grasslands in Brazil along an altitudinal gradient of 700 m (800 to 1400 m a.s.l.). Hypotheses tested were that soil properties influence the variation in AMF communities and that the frequency of the most common species of AMF is inversely influenced by the richness of other AMF. Field and laboratory data were collected on AMF community composition, richness, density, and frequency in the altitudinal gradient, and the relationships with several physical-chemical soil properties and altitude were evaluated. Fifty-one species of AMF were recorded, with 14 species being reported as possibly new to science and nine species representing new records for Brazil. This single elevation gradient alone contains 22% of the known world diversity of AMF. Soil properties and AMF community density and richness varied significantly along the elevation (p < 0.05). AMF density and richness were higher at the intermediate altitude, while AMF species composition differed statistically among the altitudes.

Local Populations of Arabidopsis thaliana Show Clear Relationship between Photoperiodic Sensitivity of Flowering Time and Altitude

PubMed Central

Lewandowska-Sabat, Anna M.; Fjellheim, Siri; Olsen, Jorunn E.; Rognli, Odd A.

2017-01-01

Adaptation of plants to local conditions that vary substantially within their geographic range is essential for seasonal timing of flowering, a major determinant of plant reproductive success. This study investigates photoperiodic responses in natural populations of Arabidopsis thaliana from high northern latitudes and their significance for local adaptation. Thirty lineages from ten local A. thaliana populations, representing different locations across an altitudinal gradient (2–850 m a.s.l.) in Norway, were grown under uniform controlled conditions, and used to screen for responses to five different photoperiods. We studied relationships between variation in photoperiodic sensitivity of flowering time, altitude, and climatic factors associated with the sites of origin. We found that variation in response to photoperiod is significantly correlated with altitude and climatic variables associated with the sites of origin of the populations. Populations originating from lower altitudes showed stronger photoperiodic sensitivity than populations from higher altitudes. Our results indicate that the altitudinal climatic gradient generates clinal variation in adaptive traits in A. thaliana. PMID:28659966

Assessment of variations in taxonomic diversity, forest structure, and aboveground biomass using remote sensing along an altitudinal gradient in tropical montane forest of Costa Rica

NASA Astrophysics Data System (ADS)

Robinson, C. M.; Saatchi, S. S.; Clark, D.; Fricker, G. A.; Wolf, J.; Gillespie, T. W.; Rovzar, C. M.; Andelman, S.

2012-12-01

This research sought to understand how alpha and beta diversity of plants vary and relate to the three-dimensional vegetation structure and aboveground biomass along environmental gradients in the tropical montane forests of Braulio Carrillo National Park in Costa Rica. There is growing evidence that ecosystem structure plays an important role in defining patterns of species diversity and along with abiotic factors (climate and edaphic) control the phenotypic and functional variations across landscapes. It is well documented that strong subdivisions at local and regional scales are found mainly on geologic or climate gradients. These general determinants of biodiversity are best demonstrated in regions with natural gradients such as tropical montane forests. Altitudinal gradients provide a landscape scale changes through variations in topography, climate, and edaphic conditions on which we tested several theoretical and biological hypotheses regarding drivers of biodiversity. The study was performed by using forest inventory and botanical data from nine 1-ha plots ranging from 100 m to 2800 m above sea level and remote sensing data from airborne lidar and radar sensors to quantify variations in forest structure. In this study we report on the effectiveness of relating patterns of tree taxonomic alpha diversity to three-dimensional structure of a tropical montane forest using lidar and radar observations of forest structure and biomass. We assessed alpha and beta diversity at the species, genus, and family levels utilizing datasets provided by the Terrestrial Ecology Assessment and Monitoring (TEAM) Network. Through the comparison to active remote sensing imagery, our results show that there is a strong relationship between forest 3D-structure, and alpha and beta diversity controlled by variations in abiotic factors along the altitudinal gradient. Using spatial analysis with the aid of remote sensing data, we find distinct patterns along the environmental gradients defining species turnover and changes in functional diversity. The study will provide novel approaches to use detailed spatial information from remote sensing data to study relations between functional and taxonomic dimensions of diversity.

Climate change and frog calls: long-term correlations along a tropical altitudinal gradient

PubMed Central

Narins, Peter M.; Meenderink, Sebastiaan W. F.

2014-01-01

Temperature affects nearly all biological processes, including acoustic signal production and reception. Here, we report on advertisement calls of the Puerto Rican coqui frog (Eleutherodactylus coqui) that were recorded along an altitudinal gradient and compared these with similar recordings along the same altitudinal gradient obtained 23 years earlier. We found that over this period, at any given elevation, calls exhibited both significant increases in pitch and shortening of their duration. All of the observed differences are consistent with a shift to higher elevations for the population, a well-known strategy for adapting to a rise in ambient temperature. Using independent temperature data over the same time period, we confirm a significant increase in temperature, the magnitude of which closely predicts the observed changes in the frogs’ calls. Physiological responses to long-term temperature rises include reduction in individual body size and concomitantly, population biomass. These can have potentially dire consequences, as coqui frogs form an integral component of the food web in the Puerto Rican rainforest. PMID:24718765

Climate change and frog calls: long-term correlations along a tropical altitudinal gradient.

PubMed

Narins, Peter M; Meenderink, Sebastiaan W F

2014-05-22

Temperature affects nearly all biological processes, including acoustic signal production and reception. Here, we report on advertisement calls of the Puerto Rican coqui frog (Eleutherodactylus coqui) that were recorded along an altitudinal gradient and compared these with similar recordings along the same altitudinal gradient obtained 23 years earlier. We found that over this period, at any given elevation, calls exhibited both significant increases in pitch and shortening of their duration. All of the observed differences are consistent with a shift to higher elevations for the population, a well-known strategy for adapting to a rise in ambient temperature. Using independent temperature data over the same time period, we confirm a significant increase in temperature, the magnitude of which closely predicts the observed changes in the frogs' calls. Physiological responses to long-term temperature rises include reduction in individual body size and concomitantly, population biomass. These can have potentially dire consequences, as coqui frogs form an integral component of the food web in the Puerto Rican rainforest.

Adaptation and diversity along an altitudinal gradient in Ethiopian barley (Hordeum vulgare L.) landraces revealed by molecular analysis

PubMed Central

2010-01-01

Background Among the cereal crops, barley is the species with the greatest adaptability to a wide range of environments. To determine the level and structure of genetic diversity in barley (Hordeum vulgare L.) landraces from the central highlands of Ethiopia, we have examined the molecular variation at seven nuclear microsatellite loci. Results A total of 106 landrace populations were sampled in the two growing seasons (Meher and Belg; the long and short rainy seasons, respectively), across three districts (Ankober, Mojanawadera and Tarmaber), and within each district along an altitudinal gradient (from 1,798 to 3,324 m a.s.l). Overall, although significant, the divergence (e.g. FST) is very low between seasons and geographical districts, while it is high between different classes of altitude. Selection for adaptation to different altitudes appears to be the main factor that has determined the observed clinal variation, along with population-size effects. Conclusions Our data show that barley landraces from Ethiopia are constituted by highly variable local populations (farmer's fields) that have large within-population diversity. These landraces are also shown to be locally adapted, with the major driving force that has shaped their population structure being consistent with selection for adaptation along an altitudinal gradient. Overall, our study highlights the potential of such landraces as a source of useful alleles. Furthermore, these landraces also represent an ideal system to study the processes of adaptation and for the identification of genes and genomic regions that have adaptive roles in crop species. PMID:20565982

Genetic structure along an altitudinal gradient in Lippia origanoides, a promising aromatic plant species restricted to semiarid areas in northern South America

PubMed Central

Vega-Vela, Nelson Enrique; Sánchez, María Isabel Chacón

2012-01-01

The genetic diversity and population structure of Lippia origanoides, a species of the Verbenaceae family that shows promise as a crop plant, was investigated along an altitudinal gradient in the basin of the Chicamocha River in northeastern Colombia. The economic importance of the species, quality of its essential oils, and the fact that it is restricted to some few semiarid areas in northern South America may put the species at risk in a scenario of uncontrolled harvest of natural populations. Lippia origanoides was sampled along an altitudinal gradient from 365 to 2595 m.a.s.l. throughout Chicamocha River Canyon, a semiarid area in northeastern Colombia. Genetic diversity was assessed by means of AFLP markers. The number of AFLP loci (355) and the number of individuals sampled (173) were sufficient to reliably identify four populations at contrasting altitudes (FST = 0.18, P-value < 0.0000), two populations in the lower basin, one population in the medium basin, and one population in the upper basin, with a low level of admixture between them. In average, genetic diversity within populations was relatively high (Ht = 0.32; I = 0.48); nevertheless, diversity was significantly reduced at higher altitude, a pattern that may be consistent with a scenario of range expansion toward higher elevations in an environment with more extreme conditions. The differences in altitude among the basins in the Chicamocha River seem to be relevant in determining the genetic structure of this species. PMID:23170204

Selection by pollinators on floral traits in generalized Trollius ranunculoides (Ranunculaceae) along altitudinal gradients.

PubMed

Zhao, Zhi-Gang; Wang, Yi-Ke

2015-01-01

Abundance and visitation of pollinator assemblages tend to decrease with altitude, leading to an increase in pollen limitation. Thus increased competition for pollinators may generate stronger selection on attractive traits of flowers at high elevations and cause floral adaptive evolution. Few studies have related geographically variable selection from pollinators and intraspecific floral differentiation. We investigated the variation of Trollius ranunculoides flowers and its pollinators along an altitudinal gradient on the eastern Qinghai-Tibet Plateau, and measured phenotypic selection by pollinators on floral traits across populations. The results showed significant decline of visitation rate of bees along altitudinal gradients, while flies was unchanged. When fitness is estimated by the visitation rate rather than the seed number per plant, phenotypic selection on the sepal length and width shows a significant correlation between the selection strength and the altitude, with stronger selection at higher altitudes. However, significant decreases in the sepal length and width of T. ranunculoides along the altitudinal gradient did not correspond to stronger selection of pollinators. In contrast to the pollinator visitation, mean annual precipitation negatively affected the sepal length and width, and contributed more to geographical variation in measured floral traits than the visitation rate of pollinators. Therefore, the sepal size may have been influenced by conflicting selection pressures from biotic and abiotic selective agents. This study supports the hypothesis that lower pollinator availability at high altitude can intensify selection on flower attractive traits, but abiotic selection is preventing a response to selection from pollinators.

Selection by Pollinators on Floral Traits in Generalized Trollius ranunculoides (Ranunculaceae) along Altitudinal Gradients

PubMed Central

Zhao, Zhi-Gang; Wang, Yi-Ke

2015-01-01

Abundance and visitation of pollinator assemblages tend to decrease with altitude, leading to an increase in pollen limitation. Thus increased competition for pollinators may generate stronger selection on attractive traits of flowers at high elevations and cause floral adaptive evolution. Few studies have related geographically variable selection from pollinators and intraspecific floral differentiation. We investigated the variation of Trollius ranunculoides flowers and its pollinators along an altitudinal gradient on the eastern Qinghai-Tibet Plateau, and measured phenotypic selection by pollinators on floral traits across populations. The results showed significant decline of visitation rate of bees along altitudinal gradients, while flies was unchanged. When fitness is estimated by the visitation rate rather than the seed number per plant, phenotypic selection on the sepal length and width shows a significant correlation between the selection strength and the altitude, with stronger selection at higher altitudes. However, significant decreases in the sepal length and width of T. ranunculoides along the altitudinal gradient did not correspond to stronger selection of pollinators. In contrast to the pollinator visitation, mean annual precipitation negatively affected the sepal length and width, and contributed more to geographical variation in measured floral traits than the visitation rate of pollinators. Therefore, the sepal size may have been influenced by conflicting selection pressures from biotic and abiotic selective agents. This study supports the hypothesis that lower pollinator availability at high altitude can intensify selection on flower attractive traits, but abiotic selection is preventing a response to selection from pollinators. PMID:25692295

Buried Seed Banks as Indicators of Seed Output along an Altitudinal Gradient.

ERIC Educational Resources Information Center

Thompson, K.

1985-01-01

Study of buried seed banks (viable seeds deposited in the soil near parent plants) provides a relatively easy way of determining cumulative effects on seed production and species' altitudinal limits. Sites, methods, validity, interpretation, problems of collection on a mountain, and germination techniques are discussed. (Author/DH)

Sex Ratio and Reproductive Effort in the Dioecious Juniperus communis subsp. alpina (Suter) Čelak. (Cupressaceae) Along an Altitudinal Gradient

PubMed Central

ORTIZ, PEDRO LUIS; ARISTA, MONTSERRAT; TALAVERA, SALVADOR

2002-01-01

The hypothesis that reproductive cost differs between sexes was tested in Juniperus communis subsp. alpina along an altitudinal gradient. Sex ratio (male : female) increased significantly with elevation, and above 2600 m it was significantly male‐biased. The reproductive effort was markedly greater for females than for males at all elevations. However, over 3 years of study, the growth of the females, measured as elongation of the main axes, was similar to that of the males. In both sexes, growth decreased with increasing elevation. Neither size of the ripe seed cones, nor the number of developed seeds per cone varied with elevation. The percentage of filled seeds was significantly greater at higher elevations indicating more favourable conditions for wind pollination in these stands. However, cone production decreased with elevation and so, reproductive success of J. communis subsp. alpina in Sierra Nevada decreases towards both upper and lower altitudinal distribution limits. The results do not support the hypothesis of differential reproductive cost between sexes; thus, alternative arguments to explain the altitudinal variation of sex ratio are discussed. PMID:12099351

Sex ratio and reproductive effort in the dioecious Juniperus communis subsp. alpina (Suter) Celak. (Cupressaceae) along an altitudinal gradient.

PubMed

Ortiz, Pedro Luis; Arista, Montserrat; Talavera, Salvador

2002-02-01

The hypothesis that reproductive cost differs between sexes was tested in Juniperus communis subsp. alpina along an altitudinal gradient. Sex ratio (male : female) increased significantly with elevation, and above 2,600 m it was significantly male-biased. The reproductive effort was markedly greater for females than for males at all elevations. However, over 3 years of study, the growth of the females, measured as elongation of the main axes, was similar to that of the males. In both sexes, growth decreased with increasing elevation. Neither size of the ripe seed cones, nor the number of developed seeds per cone varied with elevation. The percentage of filled seeds was significantly greater at higher elevations indicating more favourable conditions for wind pollination in these stands. However, cone production decreased with elevation and so, reproductive success of J. communis subsp. alpina in Sierra Nevada decreases towards both upper and lower altitudinal distribution limits. The results do not support the hypothesis of differential reproductive cost between sexes; thus, alternative arguments to explain the altitudinal variation of sex ratio are discussed.

Altitudinal, temporal and trophic partitioning of flower-visitors in Alpine communities.

PubMed

Lefebvre, Vincent; Villemant, Claire; Fontaine, Colin; Daugeron, Christophe

2018-03-16

The cross-pollination of most alpine plants depends on insects, whose altitudinal distribution is limited by temperature. However, although global warming is causing shifts in temporal and spatial species distribution, we are still largely unaware of how plant-pollinator interactions change with elevation and time along altitudinal gradients. This makes the detection of endangered interactions and species challenging. In this study, we aimed at providing such a reference, and tested if and how the major flower-visiting insect orders and families segregated by altitude, phenology and foraging preferences along an elevational gradient from 970 m to 2700 m in the Alps. Flies were the main potential pollinators from 1500 m, as bees and beetles decreased rapidly above that limit. Diptera, Coleoptera and Hymenoptera differed significantly in the angiosperm assemblages visited. Within Diptera, the predominant group, major families segregated by both phenology and foraging preferences along the gradient. Empidids, muscids and anthomyiids, whose role in pollination has never been investigated, dominated the upper part of the gradient. Our results thus suggest that flies and the peculiar plants they visit might be particularly at risk under global warming, and highlight the blatant lack of studies about critical components of these rich, yet fragile mountain ecosystems.

Pattern of NDVI-based vegetation greening along an altitudinal gradient in the eastern Himalayas and its response to global warming.

PubMed

Li, Haidong; Jiang, Jiang; Chen, Bin; Li, Yingkui; Xu, Yuyue; Shen, Weishou

2016-03-01

The eastern Himalayas, especially the Yarlung Zangbo Grand Canyon Nature Reserve (YNR), is a global hotspot of biodiversity because of a wide variety of climatic conditions and elevations ranging from 500 to > 7000 m above sea level (a.s.l.). The mountain ecosystems at different elevations are vulnerable to climate change; however, there has been little research into the patterns of vegetation greening and their response to global warming. The objective of this paper is to examine the pattern of vegetation greening in different altitudinal zones in the YNR and its relationship with vegetation types and climatic factors. Specifically, the inter-annual change of the normalized difference vegetation index (NDVI) and its variation along altitudinal gradient between 1999 and 2013 was investigated using SPOT-VGT NDVI data and ASTER global digital elevation model (GDEM) data. We found that annual NDVI increased by 17.58% in the YNR from 1999 to 2013, especially in regions dominated by broad-leaved and coniferous forests at lower elevations. The vegetation greening rate decreased significantly as elevation increased, with a threshold elevation of approximately 3000 m. Rising temperature played a dominant role in driving the increase in NDVI, while precipitation has no statistical relationship with changes in NDVI in this region. This study provides useful information to develop an integrated management and conservation plan for climate change adaptation and promote biodiversity conservation in the YNR.

Classification and ordination of main plant communities along an altitudinal gradient in the arid and temperate climates of northeastern Mexico.

PubMed

Castillón, Eduardo Estrada; Arévalo, José Ramón; Quintanilla, José Ángel Villarreal; Rodríguez, María Magdalena Salinas; Encina-Domínguez, Juan Antonio; Rodríguez, Humberto González; Ayala, César Martín Cantú

2015-10-01

Quantitative data on the ecology of the main plant communities along an altitudinal gradient in northeastern Mexico were obtained with the aim of identifying the most important environmental variables that affect plant distribution and composition. The main threats to these communities were also investigated. Importance value index (IVi) of the 39 most important species and 16 environmental variables were recorded at 35 altitudinal gradients each spaced at intervals of at least 100-m altitude. Classification and ordination of vegetation showed six well-differentiated but overlapping plant communities: alpine meadow, cold conifer forest, mesic mixed forest, xeric scrub, Tamaulipan piedmont scrub, and halophytic grassland. Altitude, minimum and average temperatures, and organic matter content are the main variables affecting the plant distribution in northeastern Mexico. Urban growth, mechanized agriculture, and changes in land use are the main threats in the short and medium term to plant communities in this area. Climate change also seems to be having an impact at present or in the near future as shown by the presence of exotic shrubs from warmer areas in mesic and temperate areas inhabited by oak and oak-pine forest.

Carbon and nitrogen dynamics of soil and litter along an altitudinal gradient in Atlantic Forest

NASA Astrophysics Data System (ADS)

Piccolo, M. D.; Martins, S. C.; Camargo, P. B.; Carmo, J. B.; Sousa Neto, E.; Martinelli, L. A.

2008-12-01

The Ombrophylus Dense Forest or Atlantic Forest is the second most important Biome in extension of Brazil, and it is considered a hot-spot in terms of biodiversity. It is localized in Brazilian Coast, and it covered originally 1.2 million km2, but currently only 8% of the original forest remains. The study was carried out in Sao Paulo State, Brazil (23° 24' S and 45° 11' W). The studied areas were: Restinga Vegetation (RV), 5 m above sea level; Low Altitude Ombrophylus Dense Forest (LAODF), 100 m asl; Submontane Ombrophylus Dense Forest (SODF), 600m asl and; Montane Ombrophylus Dense Forest (MODF), 1000 m asl. The aim of this study was to evaluate the effect of altitudinal gradient, with specific phytophysiognomies, on C and N dynamics in the soil and litter at Atlantic Forest. A sampling area of 1 ha was subdivided in contiguous sub- parcels (10 x 10 m). The forest floor litter accumulated (0.06 m2) was collected monthly (n=60), during 12 months, in each phytophysiognomies. Soils samples (0-0.05m depth) were collected (n=32) from square regular grids, 30 m away from each other. Changes in litter contents of C and N were not detected along the altitudinal gradient, and the values observed were 400 and 15g kg-1 for C and N, respectively. Litter ä13C values did not change significantly with the altitudinal gradient and were represented by C3 plants values. The C and N stocks were high in the clay soils (LAODF, SODF and MODF) when compared to sandy soil (RV). The soil C stocks (24 to 30 Mg ha-1) were similar among the altitudinal gradients, except RV (16 Mg ha-1). The areas of elevated altitude (MODF and SODF) showed high N stocks (2.3 Mg ha-1), followed by LAODF (1.8Mg ha-1) and RV (0.9Mg ha-1). In all altitudes there was 13C enrichment with soil depth, and it can be explained by the different fractions of the organic matter distributed along the soil profile, and also due the effect of the isotopic dilution between the forest floor litter and the soil.

Litterfall production along successional and altitudinal gradients of subtropical monsoon evergreen broadleaved forests in Guangdong, China

USGS Publications Warehouse

Zhou, G.; Guan, L.; Wei, X.; Zhang, Dongxiao; Zhang, Q.; Yan, J.; Wen, D.; Liu, J.; Liu, S.; Huang, Z.; Kong, G.; Mo, J.; Yu, Q.

2007-01-01

Evaluation of litterfall production is important for understanding nutrient cycling, forest growth, successional pathways, and interactions with environmental variables in forest ecosystems. Litterfall was intensively studied during the period of 1982-2001 in two subtropical monsoon vegetation gradients in the Dinghushan Biosphere Reserve, Guangdong Province, China. The two gradients include: (1) a successional gradient composed of pine forest (PF), mixed pine and broadleaved forest (MF) and monsoon evergreen broadleaved forest (BF), and (2) an altitudinal gradient composed of Baiyunci ravine rain forest (BRF), Qingyunci ravine rain forest (QRF), BF and mountainous evergreen broadleaved forest (MMF). Mean annual litterfall production was 356, 861 and 849 g m-2 for PF, MF and BF of the successional gradient, and 1016, 1061, 849 and 489 g m-2 for BRF, QRF, BF and MMF of the altitudinal gradient, respectively. As expected, mean annual litterfall of the pioneer forest PF was the lowest, but rapidly increased over the observation period while those in other forests were relatively stable, confirming that forest litterfall production is closely related to successional stages and growth patterns. Leaf proportions of total litterfall in PF, MF, BF, BRF, QRF and MMF were 76.4%, 68.4%, 56.8%, 55.7%, 57.6% and 69.2%, respectively, which were consistent with the results from studies in other evergreen broadleaved forests. Our analysis on litterfall monthly distributions indicated that litterfall production was much higher during the period of April to September compared to other months for all studied forest types. Although there were significant impacts of some climate variables (maximum and effective temperatures) on litterfall production in some of the studied forests, the mechanisms of how climate factors (temperature and rainfall) interactively affect litterfall await further study. ?? 2006 Springer Science+Business Media B.V.

Biodiversity of oribatid mites (Acari: Oribatida) along an altitudinal gradient in the Central Alps.

PubMed

Fischer, Barbara M; Schatz, Heinrich

2013-01-01

Oribatid mite communities were studied in the Central Alps (Obergurgl, Tyrol, Austria). Samples were taken on four sites along an altitudinal gradient from 2050 m a.s.l to 2900 m a.s.l., in different vegetation units (pine forest, Nardetum, Caricetum, Androsacetum). A total of 86 species were found, most of them occurred only at one altitude, four species were found in all four study sites. Three taxa could not be ascribed to a certain species (Carabodes sp. Mycobates sp., Tectocepheus sp.). Species richness and density of oribatid mites decrease with increasing altitude. The results are compared with previous studies in the same region and show remarkable shifts in species composition.

Integrating the effects of latitude and altitude on the spatial differentiation of plant community diversity in a mountainous ecosystem in China

PubMed Central

Xu, Manhou; Ma, Li; Jia, Yanyan; Liu, Min

2017-01-01

Varying patterns of plant community diversity along geographical gradients are a significant topic in biodiversity research. Here, to explore the integrated effects of latitude and altitude on the plant community diversity in a mountainous ecosystem, we set Guancen Mountain in the northern section, Guandi Mountain in the middle section, and Wulu Mountain in the southern section of the Lvliang Mountains as study areas, and the plant community diversity (basal diameter and height of tree and species diversity indices of shrub and herb) was measured horizontally at different latitude gradients and vertically at different altitude gradients in late July 2015. The results showed that (1) the trees were taller and wider at the middle latitude and higher altitude with a stronger spatial heterogeneity in the structures along the latitudinal and altitudinal gradients. The evergreen tree growth preceded that of the deciduous trees in the higher latitude and lower altitude regions, whereas the deciduous tree growth preceded that of the evergreen trees in the middle latitude and higher altitude regions. (2) Shrubs and herbs tended to grow well in the lower latitude and middle-lower altitude regions. The shrubs had a larger species diversity at lower latitude and lower altitude, but the species diversity of the herbs was not sensitive to the influences of the latitudinal and altitudinal gradients. With the latitude and altitude increasing, perennial herbs tended to grow well at higher latitude and higher altitude, while annual herbs tended to thrive at the middle latitude and lower altitude. In conclusion, environmental deviations caused by latitudinal and altitudinal gradients had great influences on the spatial distributions of the plant community diversity in the Lvliang Mountains. PMID:28323909

Integrating the effects of latitude and altitude on the spatial differentiation of plant community diversity in a mountainous ecosystem in China.

PubMed

Xu, Manhou; Ma, Li; Jia, Yanyan; Liu, Min

2017-01-01

Varying patterns of plant community diversity along geographical gradients are a significant topic in biodiversity research. Here, to explore the integrated effects of latitude and altitude on the plant community diversity in a mountainous ecosystem, we set Guancen Mountain in the northern section, Guandi Mountain in the middle section, and Wulu Mountain in the southern section of the Lvliang Mountains as study areas, and the plant community diversity (basal diameter and height of tree and species diversity indices of shrub and herb) was measured horizontally at different latitude gradients and vertically at different altitude gradients in late July 2015. The results showed that (1) the trees were taller and wider at the middle latitude and higher altitude with a stronger spatial heterogeneity in the structures along the latitudinal and altitudinal gradients. The evergreen tree growth preceded that of the deciduous trees in the higher latitude and lower altitude regions, whereas the deciduous tree growth preceded that of the evergreen trees in the middle latitude and higher altitude regions. (2) Shrubs and herbs tended to grow well in the lower latitude and middle-lower altitude regions. The shrubs had a larger species diversity at lower latitude and lower altitude, but the species diversity of the herbs was not sensitive to the influences of the latitudinal and altitudinal gradients. With the latitude and altitude increasing, perennial herbs tended to grow well at higher latitude and higher altitude, while annual herbs tended to thrive at the middle latitude and lower altitude. In conclusion, environmental deviations caused by latitudinal and altitudinal gradients had great influences on the spatial distributions of the plant community diversity in the Lvliang Mountains.

Quantifying the abundance of co-occurring conifers along Inland Northwest (USA) climate gradients

Treesearch

Gerald E. Rehfeldt; Dennis E. Ferguson; Nicholas L. Crookston

2008-01-01

The occurrence and abundance of conifers along climate gradients in the Inland Northwest (USA) was assessed using data from 5082 field plots, 81% of which were forested. Analyses using the Random Forests classification tree revealed that the sequential distribution of species along an altitudinal gradient could be predicted with reasonable accuracy from a single...

Species presence frequency and diversity in different patch types along an altitudinal gradient: Larix chinensis Beissn in Qinling Mountains (China).

PubMed

Huang, Minyi; Duan, Renyan; Wang, Shixiong; Wang, Zhigao; Fan, Weiyi

2016-01-01

Forest communities are mosaic systems composed of patches classified into four different developmental patch types: gap patch (G), building patch (B), mature patch (M) and degenerate patch (D). To study the mechanisms maintaining diversity in subalpine coniferous forests, species presence frequency and diversity in the four distinct patch types (G, B, M and D) of Larix chinensis conifer forests at three altitudinal gradients in the Qinling Mountains were analyzed. Our results were as follows: (1) Different species (or functional groups) had distinct presence frequencies in the four different patch types along the altitudinal gradient; (2) Some species or functional groups (species groups sharing similar traits and responses to the environment) only occurred in some specific patches. For seed dispersal, species using wind mainly occurred in G and D, while species using small animals mainly occurred in B and M; (3) Species composition of adjacent patch types was more similar than non-adjacent patch types, based on the lower β diversity index of the former; (4) The maximum numbers of species and two diversity indices (D' and H') were found in the middle altitudes. Various gap-forming processes and dispersal limitation may be the two major mechanisms determining species diversity in Larix chinensis coniferous forests at the patch scale.

The effect of altitude, patch size and disturbance on species richness and density of lianas in montane forest patches

NASA Astrophysics Data System (ADS)

Mohandass, Dharmalingam; Campbell, Mason J.; Hughes, Alice C.; Mammides, Christos; Davidar, Priya

2017-08-01

The species richness and density of lianas (woody vines) in tropical forests is determined by various abiotic and biotic factors. Factors such as altitude, forest patch size and the degree of forest disturbance are known to exert strong influences on liana species richness and density. We investigated how liana species richness and density were concurrently influenced by altitude (1700-2360 m), forest patch size, forest patch location (edge or interior) and disturbance intensity in the tropical montane evergreen forests, of the Nilgiri and Palni hills, Western Ghats, southern India. All woody lianas (≥1 cm dbh) were enumerated in plots of 30 × 30 m in small, medium and large forest patches, which were located along an altitudinal gradient ranging from 1700 to 2360 m. A total of 1980 individual lianas were recorded, belonging to 45 species, 32 genera and 21 families, from a total sampling area of 13.86 ha (across 154 plots). Liana species richness and density decreased significantly with increasing altitude and increased with increasing forest patch size. Within forest patches, the proportion of forest edge or interior habitat influenced liana distribution and succession especially when compared across the patch size categories. Liana species richness and density also varied along the altitudinal gradient when examined using eco-physiological guilds (i.e. shade tolerance, dispersal mode and climbing mechanism). The species richness and density of lianas within these ecological guilds responded negatively to increasing altitude and positively to increasing patch size and additionally displayed differing sensitivities to forest disturbance. Importantly, the degree of forest disturbance significantly altered the relationship between liana species richness and density to increasing altitude and patches size, and as such is likely the primary influence on liana response to montane forest succession. Our findings suggest that managing forest disturbance in the examined montane forests would assist in conserving local liana diversity across the examined altitudinal range.

Ectotherm thermal stress and specialization across altitude and latitude.

PubMed

Buckley, Lauren B; Miller, Ethan F; Kingsolver, Joel G

2013-10-01

Gradients of air temperature, radiation, and other climatic factors change systematically but differently with altitude and latitude. We explore how these factors combine to produce altitudinal and latitudinal patterns of body temperature, thermal stress, and seasonal overlap that differ markedly from patterns based solely on air temperature. We use biophysical models to estimate body temperature as a function of an organism's phenotype and environmental conditions (air and surface temperatures and radiation). Using grasshoppers as a case study, we compare mean body temperatures and the incidence of thermal extremes along altitudinal gradients both under past and current climates. Organisms at high elevation can experience frequent thermal stress despite generally cooler air temperatures due to high levels of solar radiation. Incidences of thermal stress have increased more rapidly than have increases in mean conditions due to recent climate change. Increases in air temperature have coincided with shifts in cloudiness and solar radiation, which can exacerbate shifts in body temperature. We compare altitudinal thermal gradients and their seasonality between tropical and temperate mountains to ask whether mountain passes pose a greater physiological barrier in the tropics (Janzen's hypothesis). We find that considering body temperature rather than air temperature generally increases the amount of overlap in thermal conditions along gradients in elevation and thus decreases the physiological barrier posed by tropical mountains. Our analysis highlights the limitations of predicting thermal stress based solely on air temperatures, and the importance of considering how phenotypes influence body temperatures.

Variation of maximum tree height and annual shoot growth of Smith fir at various elevations in the Sygera Mountains, southeastern Tibetan Plateau.

PubMed

Wang, Yafeng; Čufar, Katarina; Eckstein, Dieter; Liang, Eryuan

2012-01-01

Little is known about tree height and height growth (as annual shoot elongation of the apical part of vertical stems) of coniferous trees growing at various altitudes on the Tibetan Plateau, which provides a high-elevation natural platform for assessing tree growth performance in relation to future climate change. We here investigated the variation of maximum tree height and annual height increment of Smith fir (Abies georgei var. smithii) in seven forest plots (30 m×40 m) along two altitudinal transects between 3,800 m and 4,200/4,390 m above sea level (a.s.l.) in the Sygera Mountains, southeastern Tibetan Plateau. Four plots were located on north-facing slopes and three plots on southeast-facing slopes. At each site, annual shoot growth was obtained by measuring the distance between successive terminal bud scars along the main stem of 25 trees that were between 2 and 4 m high. Maximum/mean tree height and mean annual height increment of Smith fir decreased with increasing altitude up to the tree line, indicative of a stress gradient (the dominant temperature gradient) along the altitudinal transect. Above-average mean minimum summer (particularly July) temperatures affected height increment positively, whereas precipitation had no significant effect on shoot growth. The time series of annual height increments of Smith fir can be used for the reconstruction of past climate on the southeastern Tibetan Plateau. In addition, it can be expected that the rising summer temperatures observed in the recent past and anticipated for the future will enhance Smith fir's growth throughout its altitudinal distribution range.

Abundance and activity of soil microorganisms in Cedrus atlantica forests are more related to land use than to altitude or latitude

NASA Astrophysics Data System (ADS)

Ramírez Rojas, Irene; Perez Fernandez, María; Moreno Gallardo, Laura; Lechuga Ordoñez, Victor; Linares, Juan Carlos

2016-04-01

Several environmental traits might change the abundance and the function of soil microorganisms in forest soils by plant-mediated reactions. Few studies have related the landscape-scale forest structural diversity with the micro-scale distribution of microorganism and their activities. High mountain environments harbor ecosystems that are very sensitive to global change and hence highly vulnerable, as those of Atlantic cedar. Altitudinal gradients in mountains are orrelated with changes in vegetation. We propose that altitudinal gradients drive shifts in microbial communities and are correlated with land uses. Thus, the latitudinal and longitudinal pattern of abundance and activity of soil micro-organisms was studied in an intercontinental comparison. We investigate soil extractable organic carbon (EOC) and nitrogen and carbon, microbial biomass and microbial metabolic activities at eight different sites along the latitudinal range of Cedrus atlantica, covering different altitudes and soils characteristics both in Southern Spain and Northern Morocco. Analyses of the abundances of total bacteria, (16S rRNA gene), was conducted using the Ilumina metagenomics technique. Results show that the stands at the highest altitudes had distinct microbial and biochemical characteristics compared with other areas. Overall, microbial activity, as measured by soil respiration, is higher in forests subjected to lower human pressure than in stands highly degraded, probably reflecting the quality of litter input that results of the influence of local assemblage of different tree, shrub and annual species, though changes in the soil N and C contents. Indeed, total soil C and N contents explained the microbial properties at every scale. Our results suggest that in contrast to the observed pronounced altitudinal changes, the kind of human-mediate land management has a stronger role in defining changes in microbial composition and activities in the investigated forest systems.

Richness and cover of nontimber economic plants along altitude in temperate Himalayan forest-use types.

PubMed

Tariq, Akash; Adnan, Muhammad; AbdElsalam, Naser M; Fouad, Hassan; Hussain, Kamran; Ullah, Riaz; Ullah, Ahsan

2014-01-01

Pakistani Himalaya stretches over a wide range of altitudinal gradients and supports high diversity of medicinal plants that are an important source for rural livelihood. Altitudinal effects on ground vegetation have already been indicated but ground vegetation is also under severe threat of grazing and over collection. The present study investigated the effect of altitude on medicinal plants abundance in both old-growth and derived woodland forests. Each of the five line transects was selected in old-growth and derived woodland forests. Each line transect consisted of four plots distributed at four altitudinal levels (2200, 2300, 2400, and 2500 m asl). Species richness under derived woodland had shown strong negative correlation (r = -0.95) with altitude while it was found to be nonsignificant under old-growth. Cover of most of the species such as Veronica laxa (r = -0.95, P ≤ 0.05) had shown significant negative correlation with altitude under derived woodland. Cover abundance of some species like Valeriana jatamansi and Viola canescens has also shown significant negative correlation under old-growth forest. Derived woodland can decrease the cover abundance of valuable medicinal plants towards extension at higher altitudes. Thus, protection of the derived woodland could serve as a tool for the improvement of rural livelihood and ecological restoration.

Richness and Cover of Nontimber Economic Plants along Altitude in Temperate Himalayan Forest-Use Types

PubMed Central

Tariq, Akash; Adnan, Muhammad; AbdElsalam, Naser M.; Fouad, Hassan; Hussain, Kamran; Ullah, Ahsan

2014-01-01

Pakistani Himalaya stretches over a wide range of altitudinal gradients and supports high diversity of medicinal plants that are an important source for rural livelihood. Altitudinal effects on ground vegetation have already been indicated but ground vegetation is also under severe threat of grazing and over collection. The present study investigated the effect of altitude on medicinal plants abundance in both old-growth and derived woodland forests. Each of the five line transects was selected in old-growth and derived woodland forests. Each line transect consisted of four plots distributed at four altitudinal levels (2200, 2300, 2400, and 2500 m asl). Species richness under derived woodland had shown strong negative correlation (r = −0.95) with altitude while it was found to be nonsignificant under old-growth. Cover of most of the species such as Veronica laxa (r = −0.95, P ≤ 0.05) had shown significant negative correlation with altitude under derived woodland. Cover abundance of some species like Valeriana jatamansi and Viola canescens has also shown significant negative correlation under old-growth forest. Derived woodland can decrease the cover abundance of valuable medicinal plants towards extension at higher altitudes. Thus, protection of the derived woodland could serve as a tool for the improvement of rural livelihood and ecological restoration. PMID:25032237

The neotropical shrub Lupinus elegans, fromtemperate forests, may not adapt to climate change.

PubMed

Soto-Correa, J C; Sáenz-Romero, C; Lindig-Cisneros, R; de la Barrera, E

2013-05-01

Considering that their distribution is limited to altitudinal gradients along mountains that are likely to become warmer and drier, climate change poses an increased threat to temperate forest species from tropical regions. We studied whether the understorey shrub Lupinus elegans, endemic to temperate forests of west-central Mexico, will be able to withstand the projected temperature increase under seven climate change scenarios. Seeds were collected along an altitudinal gradient and grown in a shade-house over 7 months before determining their temperature tolerance as electrolyte leakage. The plants from colder sites tolerated lower temperatures, i.e. the temperature at which half of the maximum electrolyte leakage occurred (LT50), ranged from −6.4 ± 0.7 to −2.4 ± 0.3 °C. In contrast, no pattern was found for tolerance to high temperature (LT50 average 42.8 ± 0.3 °C). The climate change scenarios considered here consistently estimated an increase in air temperature during the present century that was higher for the maximum air temperature than for the mean or minimum. In particular, the anomaly from the normal maximum air temperature at the study region ranged from 2.8 °C by 2030 to 5.8 °C by 2090. In this respect, the inability of L. elegans to adapt to increasingly higher temperatures found here, in addition to a possible inhibition of reproduction caused by warmer winters, may limit its future distribution.

Multilocus Analyses Reveal Postglacial Demographic Shrinkage of Juniperus morrisonicola (Cupressaceae), a Dominant Alpine Species in Taiwan

PubMed Central

Chiu, Chi-Te; Huang, Chao-Li; Hung, Kuo-Hsiang; Chiang, Tzen-Yuh

2016-01-01

Postglacial climate changes alter geographical distributions and diversity of species. Such ongoing changes often force species to migrate along the latitude/altitude. Altitudinal gradients represent assemblage of environmental, especially climatic, variable factors that influence the plant distributions. Global warming that triggered upward migrations has therefore impacted the alpine plants on an island. In this study, we examined the genetic structure of Juniperus morrisonicola, a dominant alpine species in Taiwan, and inferred historical, demographic dynamics based on multilocus analyses. Lower levels of genetic diversity in north indicated that populations at higher latitudes were vulnerable to climate change, possibly related to historical alpine glaciers. Neither organellar DNA nor nuclear genes displayed geographical subdivisions, indicating that populations were likely interconnected before migrating upward to isolated mountain peaks, providing low possibilities of seed/pollen dispersal across mountain ranges. Bayesian skyline plots suggested steady population growth of J. morrisonicola followed by recent demographic contraction. In contrast, most lower-elevation plants experienced recent demographic expansion as a result of global warming. The endemic alpine conifer may have experienced dramatic climate changes over the alternation of glacial and interglacial periods, as indicated by a trend showing decreasing genetic diversity with the altitudinal gradient, plus a fact of upward migration. PMID:27561108

Multilocus Analyses Reveal Postglacial Demographic Shrinkage of Juniperus morrisonicola (Cupressaceae), a Dominant Alpine Species in Taiwan.

PubMed

Huang, Chi-Chun; Hsu, Tsai-Wen; Wang, Hao-Ven; Liu, Zin-Huang; Chen, Yi-Yen; Chiu, Chi-Te; Huang, Chao-Li; Hung, Kuo-Hsiang; Chiang, Tzen-Yuh

2016-01-01

Postglacial climate changes alter geographical distributions and diversity of species. Such ongoing changes often force species to migrate along the latitude/altitude. Altitudinal gradients represent assemblage of environmental, especially climatic, variable factors that influence the plant distributions. Global warming that triggered upward migrations has therefore impacted the alpine plants on an island. In this study, we examined the genetic structure of Juniperus morrisonicola, a dominant alpine species in Taiwan, and inferred historical, demographic dynamics based on multilocus analyses. Lower levels of genetic diversity in north indicated that populations at higher latitudes were vulnerable to climate change, possibly related to historical alpine glaciers. Neither organellar DNA nor nuclear genes displayed geographical subdivisions, indicating that populations were likely interconnected before migrating upward to isolated mountain peaks, providing low possibilities of seed/pollen dispersal across mountain ranges. Bayesian skyline plots suggested steady population growth of J. morrisonicola followed by recent demographic contraction. In contrast, most lower-elevation plants experienced recent demographic expansion as a result of global warming. The endemic alpine conifer may have experienced dramatic climate changes over the alternation of glacial and interglacial periods, as indicated by a trend showing decreasing genetic diversity with the altitudinal gradient, plus a fact of upward migration.

Ground Dwelling Ants as Surrogates for Establishing Conservation Priorities in the Australian Wet Tropics

PubMed Central

Yek, Sze Huei; Willliams, Stephen E; Burwell, Chris J.; Robson, Simon K.A.; Crozier, Ross H.

2009-01-01

This study aims to identify a set of areas with high biodiversity value over a small spatial scale within the Australian Wet Tropics. We identified sites of high biodiversity value across an altitudinal gradient of ground dwelling ant communities using three measures of biodiversity. The three measures considered were estimated species richness, complementarity between sites and evolutionary history. The latter measure was derived using the systematic nomenclature of the ants to infer a surrogate phylogeny. The goal of conservation assessments could then be achieved by choosing the most diverse site combinations. This approach was found to be valuable for identifying the most diverse site combinations across an altitudinal gradient that could ensure the preservation of terrestrial ground dwelling invertebrates in the Australian Wet Tropics. PMID:19613441

Nonlinear Distribution Pattern of Hibernating Bats in Caves along an Elevational Gradient in Mountain (Carpathians, Southern Poland)

PubMed Central

Piksa, Krzysztof; Nowak, Jakub; Żmihorski, Michał; Bogdanowicz, Wiesław

2013-01-01

Background Thermal gradients along changes in elevation in mountainous environments are reflected by different biotas. Although there have been studies of elevation variation in bat assemblages in summer, winter changes in the same gradients remain unknown. Methodology/Principal Findings The objective of this study was to document changes in the species composition of bats hibernating in caves along a temperate elevational gradient. We studied 70 caves between from 300 m to 1,930 m altitude along a slope of the Carpathian Mountains in southern Poland. We recorded changes in bats, including species richness, abundance, altitudinal distribution and dominance during consecutive winters between 2003 and 2009. Similarity of dominance of faunal structure was assessed by using the Bray-Curtis similarity index. We used the generalised additive model and rarefaction to study the variation in species richness, and generalized additive mixed models to examine the effect of abiotic factors on the qualitative and quantitative structure of bat assemblages. During 351 surveys we recorded 13,856 hibernating bats from 15 species. Species richness peaked around mid-elevation (1,100–1,400 m a.s.l.) with richness declining at both higher and lower elevations. Based on the results of a cluster analysis, we could distinguish among four altitudinal zones that differed in species richness and dominance structure. Conclusions/Significance This is the first study documenting changes in species richness and variation of structure of bats hibernating in caves along an elevational gradient. The most surprising and key finding is the fact that changes in the structure of assemblages of hibernating bats along the altitudinal gradient occurred in jumps, forming zones similar to those observed in the vegetation zones. Moreover, species richness and dominance structure of assemblages of hibernating bats in the mountains depended not only on location above sea level, but also on local geomorphologic conditions which strongly affected the microclimate of the caves. PMID:23861850

Quantifying the abundance of co-occurring conifers along Inland Northwest (USA) climate gradients.

PubMed

Rehfeldt, Gerald E; Ferguson, Dennis E; Crookston, Nicholas L

2008-08-01

The occurrence and abundance of conifers along climate gradients in the Inland Northwest (USA) was assessed using data from 5082 field plots, 81% of which were forested. Analyses using the Random Forests classification tree revealed that the sequential distribution of species along an altitudinal gradient could be predicted with reasonable accuracy from a single climate variable, a growing-season dryness index, calculated from the ratio of degree-days >5 degrees C that accumulate in the frost-free season to the summer precipitation. While the appearance and departure of species in an ascending altitudinal sequence were closely related to the dryness index, the departure was most easily visualized in relation to negative degree-days (degree-days < 0 degrees C). The results were in close agreement with the works of descriptive ecologists. A Weibull response function was used to predict from climate variables the abundance and occurrence probabilities of each species, using binned data. The fit of the models was excellent, generally accounting for >90% of the variance among 100 classes.

Dissolved Organic Carbon in Headwater Streams and Riparian Soil Organic Carbon along an Altitudinal Gradient in the Wuyi Mountains, China

PubMed Central

Huang, Wei; McDowell, William H.; Zou, Xiaoming; Ruan, Honghua; Wang, Jiashe; Li, Liguang

2013-01-01

Stream water dissolved organic carbon (DOC) correlates positively with soil organic carbon (SOC) in many biomes. Does this relationship hold in a small geographic region when variations of temperature, precipitation and vegetation are driven by a significant altitudinal gradient? We examined the spatial connectivity between concentrations of DOC in headwater stream and contents of riparian SOC and water-soluble soil organic carbon (WSOC), riparian soil C:N ratio, and temperature in four vegetation types along an altitudinal gradient in the Wuyi Mountains, China. Our analyses showed that annual mean concentrations of headwater stream DOC were lower in alpine meadow (AM) than in subtropical evergreen broadleaf forest (EBF), coniferous forest (CF), and subalpine dwarf forest (SDF). Headwater stream DOC concentrations were negatively correlated with riparian SOC as well as WSOC contents, and were unrelated to riparian soil C:N ratio. Our findings suggest that DOC concentrations in headwater streams are affected by different factors at regional and local scales. The dilution effect of higher precipitation and adsorption of soil DOC to higher soil clay plus silt content at higher elevation may play an important role in causing lower DOC concentrations in AM stream of the Wuyi Mountains. Our results suggest that upscaling and downscaling of the drivers of DOC export from forested watersheds when exploring the response of carbon flux to climatic change or other drivers must done with caution. PMID:24265737

[Which factors determine the altitudinal distribution of tropical Andean riverine fishes]?

PubMed

De La Barra, Evans; Zubieta, José; Aguilera, Gastón; Maldonado, Mabel; Pouilly, Marc; Oberdorff, Thierry

2016-03-01

Altitudinal gradients represent an appropriate system to assess whether there is a relationship between richness patterns, environmental variables, and the ecological processes that determine the species type and number inhabiting a given area. In mountain streams freshwater fishes, the most prevalent relationship is a monotonic decrease in species richness with elevation. The objective of this study was to evaluate four hypotheses that can explain the negative relationship between local fish species richness and altitude, 1) the hypothesis of decreasing energy availability, 2) the hypothesis of increasing climate severity, 3) the hypothesis of habitat diversity, and 4) the hypothesis of isolation by physical severity of the environment. Fish and macro-invertebrates were collected following standard methods from 83 sites (between 200-4 000 meters) of two river basins in the Bolivian Amazon. The first hypothesis was tested by analyzing relationships between the density of macro-invertebrates, the richness of invertivorous fish species and altitude; while the second and third hypotheses were assessed by a multiple regression analysis (GLM) between fish species richness and several local and regional factors. Besides, assemblage dissimilarity between sites along the altitudinal gradient was analyzed using βsim and βness indices. Fish richness decreases linearly with increasing altitude. The density of macro-invertebrates tends to increase at higher altitudes, contrary to invertivorous fish species richness, suggesting that energy availability is not a limiting factor for fish species colonization. The GLM explained 86 % of the variation in fish species richness, with a significant contribution of water temperature, maximum slope in the river mainstem, and stream width. There is a higher species turnover (βsim) between sites at low elevation. Inversely, βness shows higher values in the upper parts, corresponding to change in assemblages mainly due to species loss. Taken together, these results suggest that climatic and physical severities create strong barriers to colonization, further explaining the decrease in fish richness along the altitudinal gradient.

Altitudinal gradients, midwinter melt, and wind effects on snow accumulation in semiarid midlatitude Andes under La Niña conditions

NASA Astrophysics Data System (ADS)

Ayala, A.; McPhee, J.; Vargas, X.

2014-04-01

The Andes Cordillera remains a sparsely monitored and studied snow hydrology environment in comparison to similar mountain ranges in the Northern Hemisphere. In order to uncover some of the key processes driving snow water equivalent (SWE) spatial variability, we present and analyze a distributed SWE data set, sampled at the end of accumulation season 2011. Three representative catchments across the region were monitored, obtaining measurements in an elevation range spanning 2000 to 3900 m asl and from 32.4° to 34.0°S in latitude. Climatic conditions during this season corresponded to a moderate La Niña phenomenon, which is generally correlated with lower-than normal accumulation. Collected measurements can be described at the regional and watershed extents by altitudinal gradients that imply an increase by a factor of two in snow depth between 2200 and 3000 m asl, though with significant variability at the upper sites. In these upper sites, we found north-facing, wind-sheltered slopes showing 25% less average SWE values than south-facing, wind-exposed ones. This suggests that under these conditions, solar radiation dominated wind transport effects in controlling end-of-winter variability. Nevertheless, we found clusters of snow depth measurements above 3000 m asl that can be explained by wind exposure differences. This is the first documented snow depth data set of this spatial extent for this region, and it is framed within an ongoing research effort aimed at improving understanding and modeling of snow hydrology in the extratropical Andes Cordillera.

Forest filter effect versus cold trapping effect on the altitudinal distribution of PCBs: a case study of Mt. Gongga, eastern Tibetan Plateau.

PubMed

Liu, Xin; Li, Jun; Zheng, Qian; Bing, Haijian; Zhang, Ruijie; Wang, Yan; Luo, Chunling; Liu, Xiang; Wu, Yanhong; Pan, Suhong; Zhang, Gan

2014-12-16

Mountains are observed to preferentially accumulate persistent organic pollutants (POPs) at higher altitude due to the cold condensation effect. Forest soils characterized by high organic carbon are important for terrestrial storage of POPs. To investigate the dominant factor controlling the altitudinal distribution of POPs in mountainous areas, we measured concentrations of polychlorinated biphenyls (PCBs) in different environmental matrices (soil, moss, and air) from nine elevations on the eastern slope of Mt. Gongga, the highest mountain in Sichuan Province on the Tibetan Plateau. The concentrations of 24 measured PCBs ranged from 41 to 510 pg/g dry weight (dw) (mean: 260 pg/g dw) in the O-horizon soil, 280 to 1200 pg/g dw (mean: 740 pg/g dw) in moss, and 33 to 60 pg/m(3) (mean: 47 pg/m(3)) in air. Soil organic carbon was a key determinant explaining 75% of the variation in concentration along the altitudinal gradient. Across all of the sampling sites, the average contribution of the forest filter effect (FFE) was greater than that of the mountain cold trapping effect based on principal components analysis and multiple linear regression. Our results deviate from the thermodynamic theory involving cold condensation at high altitudes of mountain areas and highlight the importance of the FFE.

Distribution of millipedes along an altitudinal gradient in the south of Lake Teletskoye, Altai Mts, Russia (Diplopoda)

PubMed Central

Nefedieva, Julia S.; Nefediev, Pavel S.; Sakhnevich, Miroslava B.; Dyachkov, Yuri V.

2015-01-01

Abstract The distribution of millipedes along an altitudinal gradient in the south of Lake Teletskoye, Altai, Russia based on new samples from the Kyga Profile sites, as well as on partly published and freshly revised material (Mikhaljova et al. 2007, 2008, 2014, Nefedieva and Nefediev 2008, Nefediev and Nefedieva 2013, Nefedieva et al. 2014), is established. The millipede diversity is estimated to be at least 15 species and subspecies from 10 genera, 6 families and three orders. The bulk of species diversity is confined both to low- and mid-mountain chern taiga forests and high-mountain shrub tundras, whereas the highest numbers, reaching up to 130 ind./m², is shown in subalpine Pinus sibirica sparse growths. Based on clustering studied localities on species diversity similarity two groups of sites are defined: low-mountain sites and subalpine sparse growths of Pinus sibirica ones. PMID:26257540

Hybridization during altitudinal range shifts: nuclear introgression leads to extensive cyto-nuclear discordance in the fire salamander.

PubMed

Pereira, Ricardo J; Martínez-Solano, Iñigo; Buckley, David

2016-04-01

Ecological models predict that, in the face of climate change, taxa occupying steep altitudinal gradients will shift their distributions, leading to the contraction or extinction of the high-elevation (cold-adapted) taxa. However, hybridization between ecomorphologically divergent taxa commonly occurs in nature and may lead to alternative evolutionary outcomes, such as genetic merger or gene flow at specific genes. We evaluate this hypothesis by studying patterns of divergence and gene flow across three replicate contact zones between high- and low-elevation ecomorphs of the fire salamander (Salamandra salamandra) that have experienced altitudinal range shifts over the current postglacial period. Strong population structure with high genetic divergence in mitochondrial DNA suggests that vicariant evolution has occurred over several glacial-interglacial cycles and that it has led to cryptic differentiation within ecomorphs. In current parapatric boundaries, we do not find evidence for local extinction and replacement upon postglacial expansion. Instead, parapatric taxa recurrently show discordance between mitochondrial and nuclear markers, suggesting nuclear-mediated gene flow across contact zones. Isolation with migration models support this hypothesis by showing significant gene flow across all five parapatric boundaries. Together, our results suggest that, while some genomic regions, such as the mitochondria, may follow morphologic species traits and retreat to isolated mountain tops, other genomic regions, such as nuclear markers, may flow across parapatric boundaries, sometimes leading to a complete genetic merger. We show that despite high ecologic and morphologic divergence over prolonged periods of time, hybridization allows for evolutionary outcomes alternative to extinction and replacement of taxa in response to climate change. © 2016 John Wiley & Sons Ltd.

Range shift and introgression of the rear and leading populations in two ecologically distinct Rubus species.

PubMed

Mimura, Makiko; Mishima, Misako; Lascoux, Martin; Yahara, Tetsukazu

2014-10-25

The margins of a species' range might be located at the margins of a species' niche, and in such cases, can be highly vulnerable to climate changes. They, however, may also undergo significant evolutionary changes due to drastic population dynamics in response to climate changes, which may increase the chances of isolation and contact among species. Such species interactions induced by climate changes could then regulate or facilitate further responses to climatic changes. We hypothesized that climate changes lead to species contacts and subsequent genetic exchanges due to differences in population dynamics at the species boundaries. We sampled two closely related Rubus species, one temperate (Rubus palmatus) and the other subtropical (R. grayanus) near their joint species boundaries in southern Japan. Coalescent analysis, based on molecular data and ecological niche modelling during the Last Glacial Maximum (LGM), were used to infer past population dynamics. At the contact zones on Yakushima (Yaku Island), where the two species are parapatrically distributed, we tested hybridization along altitudinal gradients. Coalescent analysis suggested that the southernmost populations of R. palmatus predated the LGM (~20,000 ya). Conversely, populations at the current northern limit of R. grayanus diverged relatively recently and likely represent young outposts of a northbound range shift. These population dynamics were partly supported by the ensemble forecasting of six different species distribution models. Both past and ongoing hybridizations were detected near and on Yakushima. Backcrosses and advanced-generation hybrids likely generated the clinal hybrid zones along altitudinal gradients on the island where the two species are currently parapatrically distributed. Climate oscillations during the Quaternary Period and the response of a species in range shifts likely led to repeated contacts with the gene pools of ecologically distinct relatives. Such species interactions, induced by climate changes, may bring new genetic material to the marginal populations where species tend to experience more extreme climatic conditions at the margins of the species distribution.

Cross-continental comparison of the functional composition and carbon allocation of two altitudinal forest transects in Ecuador and Rwanda.

NASA Astrophysics Data System (ADS)

Verbeeck, Hans; Bauters, Marijn; Bruneel, Stijn; Demol, Miro; Taveirne, Cys; Van Der Heyden, Dries; Kearsley, Elizabeth; Cizungu, Landry; Boeckx, Pascal

2017-04-01

Tropical forests are key actors in the global carbon cycle. Predicting future responses of these forests to global change is challenging, but important for global climate models. However, our current understanding of such responses is limited, due to the complexity of forest ecosystems and the slow dynamics that inherently form these systems. Our understanding of ecosystem ecology and functioning could greatly benefit from experimental setups including strong environmental gradients in the tropics, as found on altitudinal transects. We setup two such transects in both South-America and Central Africa, focussing on shifts in carbon allocation, forest structure, nutrient cycling and functional composition. The Ecuadorian transect has 16 plots (40 by 40 m) and ranges from 400 to 3000 m.a.s.l., and the Rwandan transect has 20 plots (40 by 40 m) from 1500 to 3000 m.a.s.l. All plots were inventoried and canopy, litter and soil were extensively sampled. By a cross-continental comparison of both transects, we will gain insight in how different or alike both tropical forests biomes are in their responses, and how universal the observed altitudinal adaption mechanisms are. This could provide us with vital information of the ecological responses of both biomes to future global change scenarios. Additionally, comparison of nutrient shifts and trait-based functional composition allows us to compare the biogeochemical cycles of African and South-American tropical forests.

The effects of forest-savanna-grassland gradients on bird communities of Chiquitano Dry Forests domain, in western Brazil.

PubMed

Godoi, Mauricio N; Souza, Edivaldo O DE

2016-01-01

Different vegetation types are distributed in mountains according to altitude, topography and soil. The composition and structure of bird communities in these areas can change in relation to the vegetation gradient, with particular communities occupying each habitat type. In this study we present the changes in composition, species richness and bird abundance over the gradient of forests, savannas and altitudinal grasslands of Maciço do Urucum, a mountainous region located in the Chiquitano Dry Forests domain in western Brazil. We recorded 165 bird species through qualitative and quantitative methods. Forested savannas, riparian forests and submontane forests presented the highest richness and abundance of birds, while arboreal savannas and altitudinal grasslands had intermediate and low values, respectively. The bird composition was similar between riparian and submontane forests, while other vegetation types present more dissimilar bird communities. Our results show differences in composition, richness and bird abundance among the vegetation types present at Maciço do Urucum, and highlight an important function of vegetation gradients for the conservation of bird communities in mountains. Additionally, this is the first study of the bird communities in the Brazilian Chiquitano Dry Forests, an important domain in the west of Brazil which has been poorly studied.

Climate Control on Tree Growth at the Upper and Lower Treelines: A Case Study in the Qilian Mountains, Tibetan Plateau

PubMed Central

Yang, Bao; He, Minhui; Melvin, Thomas M.; Zhao, Yan; Briffa, Keith R.

2013-01-01

It is generally hypothesized that tree growth at the upper treeline is normally controlled by temperature while that at the lower treeline is precipitation limited. However, uniform patterns of inter-annual ring-width variations along altitudinal gradients are also observed in some situations. How changing elevation influences tree growth in the cold and arid Qilian Mountains, on the northeastern Tibetan Plateau, is of considerable interest because of the sensitivity of the region’s local climate to different atmospheric circulation patterns. Here, a network of four Qilian juniper (Sabina przewalskii Kom.) ring-width chronologies was developed from trees distributed on a typical mountain slope at elevations ranging from 3000 to 3520 m above sea level (a.s.l.). The statistical characteristics of the four tree-ring chronologies show no significant correlation with increasing elevation. All the sampled tree growth was controlled by a common climatic signal (local precipitation) across the investigated altitudinal gradient (520 m). During the common reliable period, covering the past 450 years, the four chronologies have exhibited coherent growth patterns in both the high- and low-frequency domains. These results contradict the notion of contrasting climate growth controls at higher and lower elevations, and specifically the assumption that inter-annual tree-growth variability is controlled by temperature at the upper treeline. It should be stressed that these results relate to the relatively arid conditions at the sampling sites in the Qilian Mountains. PMID:23874871

Status and Extent of Ericaceous Vegetation In The Conservation of Alpine Ecosytem In The Southern Slope of Bale Mountains

NASA Astrophysics Data System (ADS)

Assefa, Y.

The Bale mountain range is located between the wet east African mountains (proper) and the dry northeast African mountains, Southeast Ethiopia. This mountain range hosts some of endemic flora and fauna which are endangered of extinction. The most extensive Ericaceous vegetation in the continent is found in Bale Mountains. The southern slope of this mountain range is known for its distinct vegetation zonation of the Afromontane forests. The Ericaceous vegetation between the montane forest and the afroalpine of this slope is relatively little disturbed than other similar Ericaceous vegetation elsewhere in Africa. Study on the distribution and structure of this vegeta- tion was made from Nov. 1999- April 2000 on the southern slope, Harrena escarpment. The vegetation north of Rira village, between 3000m and 4200m was sampled after selecting continuous homogenous sites systematically along the altitudinal gradient. Cover abundance of the species for vascular plants, frequency, height and DBH for woody treeline species were taken in 110 quadrats. The environmental parameters along the altitudinal gradient including soil pH, texture, total nitrogen, and soil mois- ture were measured. Altitude, slope, and aspect were measured for all qudrats. All the environmental and vegetation data were analyzed with Syntax, Canoco, Minitab and Sigma plot. Anthropozogenic data was taken using questionnaire and analyzed. Thir- teen community types were described and their distribution showed a clear pattern at different parts of the Ericaceous vegetation. However some of the community types which were restricted to the Afroalpine belt were found in the Ericaceous vegetation. This might be a possible indication of the expansion of the afroalpine belt to lower altitude, even below 3400 m (Erica dominated Hagenia-Hypericum zone). The height of the tree and shrub species has shown a decreasing tendency with increase in al- titude. This trend was very gradual for E. trimera. The species occurs for about 1.2 km altitudinal range showing difference in height and habit along altitudinal gradi- ent. The regression analysis (r2=0.58) has shown a consistent decrease in height along altitude. No abrupt transition was documented in the systematically selected continu- ous Ericaceous vegetation. Among the environmental parameters taken, altitude was the strongest explanatory variable. While incidence of fire is correlated with socioeco- nomic parameters and relief Soil pH, and texture have shown stronger correlation with 1 altitude. While percent total nitrogen was showing more significant (p<0.01) correla- tion with microsite factors. Local people burn the Ericaceous vegetation mainly for grazing. Therefore, strategies that may reduce the rate of fire should take into account the pasture and the semi - pastoral local communities. Creat income-generating alter- natives for increasing population at Rira village. Barley used to be cultivated around Rira village in limited places. But now, indigenous settlers who were mainly depend- ing on animal rearing are shifting to mixed farming practices with increasing popu- lation. This could jeopardize the water shade of the area, in addition to the loss of biodiversity. Increasing awareness of the people on wise use of forest through school environmental clubs is also a possible option to approach the local people.

[Altitudinal patterns of species richness and species range size of vascular plants in Xiaolong- shan Reserve of Qinling Mountain: a test of Rapoport' s rule].

PubMed

Zheng, Zhi; Gong, Da-Jie; Sun, Cheng-Xiang; Li, Xiao-Jun; Li, Wan-Jiang

2014-09-01

Altitudinal patterns of species richness and species range size and their underlying mechanisms have long been a key topic in biogeography and biodiversity research. Rapoport's rule stated that the species richness gradually declined with the increasing altitude, while the species ranges became larger. Using altitude-distribution database from Xiaolongshan Reverse, this study explored the altitudinal patterns of vascular plant species richness and species range in Qinling Xiaolongshan Reserve, and examined the relationships between species richness and their distributional middle points in altitudinal bands for different fauna, taxonomic units and growth forms and tested the Rapoport's rule by using Stevens' method, Pagel's method, mid-point method and cross-species method. The results showed that the species richness of vascular plants except small-range species showed a unimodal pattern along the altitude in Qinling Xiaolongshan Reserve and the highest proportion of small-range species was found at the lower altitudinal bands and at the higher altitudinal bands. Due to different assemblages and examining methods, the relationships between species distributing range sizes and the altitudes were different. Increasing taxonomic units was easier to support Rapoport's rule, which was related to niche differences that the different taxonomic units occupied. The mean species range size of angiosperms showed a unimodal pattern along the altitude, while those of the gymnosperms and pteridophytes were unclearly regular. The mean species range size of the climbers was wider with the increasing altitude, while that of the shrubs which could adapt to different environmental situations was not sensitive to the change of altitude. Pagel's method was easier to support the Rapoport's rule, and then was Steven's method. On the contrary, due to the mid-domain effect, the results of the test by using the mid-point method showed that the mean species range size varied in a unimodal pattern along the altitude, which didn't support the Rapoport's rule, and because of the scatter-spot impact, the explanatory power of the cross-species method was much lower.

Mosquito Species (Diptera: Culicidae) Persistence and Synchrony Across an Urban Altitudinal Gradient.

PubMed

Chaves, Luis Fernando

2017-03-01

Patterns of mosquito spatial persistence and temporal presence, as well as synchrony, i.e., the degree of concerted fluctuations in abundance, have been scarcely studied at finely grained spatial scales and over altitudinal gradients. Here, we present a spatial persistence, temporal presence, and synchrony analysis of four common mosquito species across the altitudinal gradient of Mt. Konpira in Nagasaki, Japan. We found that Aedes albopictus (Skuse) was more frequently found at the mountain base. In contrast, Aedes japonicus (Theobald) and Aedes flavopictus Yamada were common higher in the mountain, while Armigeres subalbatus (Coquillet) was uniformly present across the mountain, yet less frequently than the other species during the studied period. Our analysis showed that these spatial heterogeneities were associated with differences in landscape and microclimatic elements of Mt. Konpira. Temporally we found that presence across sampling locations was mainly synchronous across the four species and positively associated with rainfall and temperature. With the exception of Ae albopictus, where no significant synchrony was observed, mosquito species mainly showed flat synchrony profiles in Mt. Konpira when looking at the geographic (2-D) distance between their sampling locations. By contrast, when synchrony was studied across altitude, it was observed that Ae. flavopictus tracked the temperature synchrony pattern, decreasing its synchrony with the separation in altitude between sampling locations. Finally, our results suggest that differences in mosquito species persistence, temporal presence, and synchrony might be useful to understand the entomological risk of vector-borne disease transmission in urban landscapes. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Effect of environmental parameters on biodiversity of the fungal component in lithic Antarctic communities.

PubMed

Selbmann, Laura; Onofri, Silvano; Coleine, Claudia; Buzzini, Pietro; Canini, Fabiana; Zucconi, Laura

2017-11-01

A wide sampling of rocks, colonized by microbial epi-endolithic communities, was performed along an altitudinal gradient from sea level to 3600 m asl and sea distance from the coast to 100 km inland along the Victoria Land Coast, Antarctica. Seventy-two rock samples of different typology, representative of the entire survey, were selected and studied using denaturing gradient gel electrophoresis to compare variation in fungal diversity according to environmental conditions along this altitudinal and sea distance transect. Lichenized fungi were largely predominant in all the samples studied and the biodiversity was heavily influenced even by minimal local variations. The n-MDS analysis showed that altitude and sea distance affect fungal biodiversity, while sandstone allows the communities to maintain high biodiversity indices. The Pareto-Lorenz curves indicate that all the communities analyzed are highly adapted to extreme conditions but scarcely resilient, so any external perturbation may have irreversible effects on these fragile ecosystems.

Spatial distributing characteristics of land use in the southern slope of mid-Himalaya Mountains

NASA Astrophysics Data System (ADS)

Lu, Chen

2014-12-01

The southern slope of mid-Himalayan Mountains located in China's Qomolangma National Natural Reserve in Tibet Autonomous Region, is made up of several non-continuous valleys. The study collected the data including DEM(SRTM90m), 1/250,000 land use map(year 2000), 1/100 million vegetation types map ,satellite images of 4 typical valleys on Google Earth Planet Map. Made use of ArcGIS9.3 spatial analysis technology, analyzed into the 2 aspects— Mountain altitudinal belts and slope gradient of soil types of Qinghai-Tibet Plateau, so as to abtain the spatial distributing characteristics of farmland and grassland in the research areas. The conclusions indicates that: (1)no farmland below 2200m altitude, land use is influenced intensively by slope gradient factor in the altitude range of < 2500m; (2)it is in 2500m-3800m altitude range meanwhile on the 2 farming suitable slope gradient belts(<5°, 5-15°) that the very focus zone has got the relatively larger potential, suitability and yield of farming utilization; (3)on the 3 grazing suitable slope gradient belts(<5°,5-15°,15-35°), the respective fodder quantities of the 4 valleys has low differences. land use of the 4 valleys are intensively restricted by altitude and slope gradient factors so that cultivating and grazing activities take place widely on the farming unsuitable slope gradient belts(15-35°,>35°) and grazing unsuitable slope gradient belt(>35°), which is disadvantaged to ecological environmental protection and rational utilization of land resources.

Climate change and plant dispersal along corridors in fragmented landscapes of Mesoamerica

PubMed Central

Imbach, Pablo A; Locatelli, Bruno; Molina, Luis G; Ciais, Philippe; Leadley, Paul W

2013-01-01

Climate change is a threat to biodiversity, and adaptation measures should be considered in biodiversity conservation planning. Protected areas (PA) are expected to be impacted by climate change and improving their connectivity with biological corridors (BC) has been proposed as a potential adaptation measure, although assessing its effectiveness remains a challenge. In Mesoamerica, efforts to preserve the biodiversity have led to the creation of a regional network of PA and, more recently, BC. This study evaluates the role of BC for facilitating plant dispersal between PA under climate change in Mesoamerica. A spatially explicit dynamic model (cellular automaton) was developed to simulate species dispersal under different climate and conservation policy scenarios. Plant functional types (PFT) were defined based on a range of dispersal rates and vegetation types to represent the diversity of species in the region. The impacts of climate change on PA and the role of BC for dispersal were assessed spatially. Results show that most impacted PA are those with low altitudinal range in hot, dry, or high latitude areas. PA with low altitudinal range in high cool areas benefit the most from corridors. The most important corridors cover larger areas and have high altitude gradients. Only the fastest PFT can keep up with the expected change in climate and benefit from corridors for dispersal. We conclude that the spatial assessment of the vulnerability of PA and the role of corridors in facilitating dispersal can help conservation planning under a changing climate. PMID:24101983

Asymmetrical local adaptation of maize landraces along an altitudinal gradient.

PubMed

Mercer, Kristin; Martínez-Vásquez, Ángel; Perales, Hugo R

2008-08-01

Crop landraces are managed populations that evolve in response to gene flow and selection. Cross-pollination among fields, seed sharing by farmers, and selection by management and environmental conditions play roles in shaping crop characteristics. We used common gardens to explore the local adaptation of maize (Zea mays ssp. mays) landrace populations from Chiapas, Mexico to altitude. We sowed seeds of 21 populations from three altitudinal ranges in two common gardens and measured two characteristics that estimate fitness: likelihood of producing good quality seed and the total mass of good quality seed per plant. The probability of lowland plants producing good quality seed was invariably high regardless of garden, while highland landraces were especially sensitive to altitude. Their likelihood of producing good seed quadrupled in the highland site. The mass of good quality seed showed a different pattern, with lowland landraces producing 25% less seed mass than the other types at high elevations. Combining these two measures of fitness revealed that the highland landraces were clearly adapted to highland sites, while lowland and midland landraces appear more adapted to the midland site. We discuss this asymmetry in local adaptation in light of climate change and in situ conservation of crop genetic resources.

Altitudinal distribution and advertisement call of Colostethus latinasus (Amphibia: Dendrobatidae), endemic species from eastern Panama and type species of Colostethus , with a molecular assessment of similar sympatric species.

PubMed

Ibáñez, Roberto D; Griffith, Edgardo J; Lips, Karen R; Crawford, Andrew J

2017-04-12

We conducted a molecular assessment of Colostethus-like frogs along an elevational gradient in the Serranía de Pirre, above Santa Cruz de Cana, eastern Panama, aiming to establish their species identity and to determine the altitudinal distribution of C. latinasus. Our findings confirm the view of C. latinasus as an endemic species restricted to the highlands of this mountain range, i.e., 1350-1475 m.a.s.l., considered to be type locality of this species. We described the advertisement call of C. latinasus that consists of a series of 4-18 single, short and relatively loud "peep"-like notes given in rapid succession, and its spectral and temporal features were compared with calls of congeneric species. For the first time, DNA sequences from C. latinasus were obtained, since previously reported sequences were based on misidentified specimens. This is particularly important because C. latinasus is the type species of Colostethus, a genus considered paraphyletic according to recent phylogenetic analyses based on molecular data.

Leaf morphology shift linked to climate change.

PubMed

Guerin, Greg R; Wen, Haixia; Lowe, Andrew J

2012-10-23

Climate change is driving adaptive shifts within species, but research on plants has been focused on phenology. Leaf morphology has demonstrated links with climate and varies within species along climate gradients. We predicted that, given within-species variation along a climate gradient, a morphological shift should have occurred over time due to climate change. We tested this prediction, taking advantage of latitudinal and altitudinal variations within the Adelaide Geosyncline region, South Australia, historical herbarium specimens (n = 255) and field sampling (n = 274). Leaf width in the study taxon, Dodonaea viscosa subsp. angustissima, was negatively correlated with latitude regionally, and leaf area was negatively correlated with altitude locally. Analysis of herbarium specimens revealed a 2 mm decrease in leaf width (total range 1-9 mm) over 127 years across the region. The results are consistent with a morphological response to contemporary climate change. We conclude that leaf width is linked to maximum temperature regionally (latitude gradient) and leaf area to minimum temperature locally (altitude gradient). These data indicate a morphological shift consistent with a direct response to climate change and could inform provenance selection for restoration with further investigation of the genetic basis and adaptive significance of observed variation.

Morphological and colour morph clines along an altitudinal gradient in the meadow grasshopper Pseudochorthippus parallelus.

PubMed

Köhler, Günter; Samietz, Jörg; Schielzeth, Holger

2017-01-01

Many animals show altitudinal clines in size, shape and body colour. Increases in body size and reduction in the length of body appendices in colder habitats are usually attributed to improved heat conservation at lower surface-to-volume ratios (known as Bergmann's and Allen's rule, respectively). However, the patterns are more variable and sometimes reversed in small ectotherms that are affected by shortened growing seasons. Altitude can also affect colouration. The thermal melanism hypothesis predicts darker colours under cooler conditions because of a thermoregulatory advantage. Darker colours may also be favoured at high altitudes for reasons of UV protection or habitat-dependent crypsis. We studied altitudinal variation in morphology and colour in the colour-polymorphic meadow grasshopper Pseudochorthippus parallelus based on 563 individuals from 17 populations sampled between 450 and 2,500 m asl. Pronotum length did not change with altitude, while postfemur length decreased significantly in both sexes. Tegmen (forewing) length decreased in males, but not in females. The results indicate that while body size, as best quantified by pronotum length, was remarkably constant, extended appendices were reduced at high altitudes. The pattern thus follows Allen's rule, but neither Bergmann's nor converse Bergmann's rule. These results indicate that inference of converse Bergmann's rule based on measurements from appendices should be treated with some caution. Colour morph ratios showed significant changes in both sexes from lowland populations dominated by green individuals to high-altitude populations dominated by brown ones. The increase of brown morphs was particularly steep between 1,500 and 2,000 m asl. The results suggest shared control of colour in males and females and local adaptation along the altitudinal gradient following the predictions of the thermal melanism hypothesis. Interestingly, both patterns, the reduction of body appendices and the higher frequency of brown individuals, may be explained by a need for efficient thermoregulation under high-altitude conditions.

Altitudinal gradients, biogeographic history and microhabitat adaptation affect fine-scale spatial genetic structure in African and Neotropical populations of an ancient tropical tree species.

PubMed

Torroba-Balmori, Paloma; Budde, Katharina B; Heer, Katrin; González-Martínez, Santiago C; Olsson, Sanna; Scotti-Saintagne, Caroline; Casalis, Maxime; Sonké, Bonaventure; Dick, Christopher W; Heuertz, Myriam

2017-01-01

The analysis of fine-scale spatial genetic structure (FSGS) within populations can provide insights into eco-evolutionary processes. Restricted dispersal and locally occurring genetic drift are the primary causes for FSGS at equilibrium, as described in the isolation by distance (IBD) model. Beyond IBD expectations, spatial, environmental or historical factors can affect FSGS. We examined FSGS in seven African and Neotropical populations of the late-successional rain forest tree Symphonia globulifera L. f. (Clusiaceae) to discriminate the influence of drift-dispersal vs. landscape/ecological features and historical processes on FSGS. We used spatial principal component analysis and Bayesian clustering to assess spatial genetic heterogeneity at SSRs and examined its association with plastid DNA and habitat features. African populations (from Cameroon and São Tomé) displayed a stronger FSGS than Neotropical populations at both marker types (mean Sp = 0.025 vs. Sp = 0.008 at SSRs) and had a stronger spatial genetic heterogeneity. All three African populations occurred in pronounced altitudinal gradients, possibly restricting animal-mediated seed dispersal. Cyto-nuclear disequilibria in Cameroonian populations also suggested a legacy of biogeographic history to explain these genetic patterns. Conversely, Neotropical populations exhibited a weaker FSGS, which may reflect more efficient wide-ranging seed dispersal by Neotropical bats and other dispersers. The population from French Guiana displayed an association of plastid haplotypes with two morphotypes characterized by differential habitat preferences. Our results highlight the importance of the microenvironment for eco-evolutionary processes within persistent tropical tree populations.

Altitudinal gradients, biogeographic history and microhabitat adaptation affect fine-scale spatial genetic structure in African and Neotropical populations of an ancient tropical tree species

PubMed Central

Torroba-Balmori, Paloma; Budde, Katharina B.; Heer, Katrin; González-Martínez, Santiago C.; Olsson, Sanna; Scotti-Saintagne, Caroline; Sonké, Bonaventure; Dick, Christopher W.

2017-01-01

The analysis of fine-scale spatial genetic structure (FSGS) within populations can provide insights into eco-evolutionary processes. Restricted dispersal and locally occurring genetic drift are the primary causes for FSGS at equilibrium, as described in the isolation by distance (IBD) model. Beyond IBD expectations, spatial, environmental or historical factors can affect FSGS. We examined FSGS in seven African and Neotropical populations of the late-successional rain forest tree Symphonia globulifera L. f. (Clusiaceae) to discriminate the influence of drift-dispersal vs. landscape/ecological features and historical processes on FSGS. We used spatial principal component analysis and Bayesian clustering to assess spatial genetic heterogeneity at SSRs and examined its association with plastid DNA and habitat features. African populations (from Cameroon and São Tomé) displayed a stronger FSGS than Neotropical populations at both marker types (mean Sp = 0.025 vs. Sp = 0.008 at SSRs) and had a stronger spatial genetic heterogeneity. All three African populations occurred in pronounced altitudinal gradients, possibly restricting animal-mediated seed dispersal. Cyto-nuclear disequilibria in Cameroonian populations also suggested a legacy of biogeographic history to explain these genetic patterns. Conversely, Neotropical populations exhibited a weaker FSGS, which may reflect more efficient wide-ranging seed dispersal by Neotropical bats and other dispersers. The population from French Guiana displayed an association of plastid haplotypes with two morphotypes characterized by differential habitat preferences. Our results highlight the importance of the microenvironment for eco-evolutionary processes within persistent tropical tree populations. PMID:28771629

Altitudinal patterns of diversity and functional traits of metabolically active microorganisms in stream biofilms

PubMed Central

Wilhelm, Linda; Besemer, Katharina; Fragner, Lena; Peter, Hannes; Weckwerth, Wolfram; Battin, Tom J

2015-01-01

Resources structure ecological communities and potentially link biodiversity to energy flow. It is commonly believed that functional traits (generalists versus specialists) involved in the exploitation of resources depend on resource availability and environmental fluctuations. The longitudinal nature of stream ecosystems provides changing resources to stream biota with yet unknown effects on microbial functional traits and community structure. We investigated the impact of autochthonous (algal extract) and allochthonous (spruce extract) resources, as they change along alpine streams from above to below the treeline, on microbial diversity, community composition and functions of benthic biofilms. Combining bromodeoxyuridine labelling and 454 pyrosequencing, we showed that diversity was lower upstream than downstream of the treeline and that community composition changed along the altitudinal gradient. We also found that, especially for allochthonous resources, specialisation by biofilm bacteria increased along that same gradient. Our results suggest that in streams below the treeline biofilm diversity, specialisation and functioning are associated with increasing niche differentiation as potentially modulated by divers allochthonous and autochthonous constituents contributing to resources. These findings expand our current understanding on biofilm structure and function in alpine streams. PMID:25978543

Biomass and diversity of dry alpine plant communities along altitudinal gradients in the Himalayas

USGS Publications Warehouse

Namgail, T.; Rawat, G.S.; Mishra, C.; van Wieren, S.E.; Prins, H.H.T.

2012-01-01

A non-linear relationship between phytodiversity and altitude has widely been reported, but the relationship between phytomass and altitude remains little understood. We examined the phytomass and diversity of vascular plants along altitudinal gradients on the dry alpine rangelands of Ladakh, western Himalaya. We used generalized linear and generalized additive models to assess the relationship between these vegetation parameters and altitude. We found a hump-shaped relationship between aboveground phytomass and altitude. We suspect that this is engendered by low rainfall and trampling/excessive grazing at lower slopes by domestic livestock, and low temperature and low nutrient levels at higher slopes. We also found a unimodal relationship between plant species-richness and altitude at a single mountain as well as at the scale of entire Ladakh. The species-richness at the single mountain peaked between 5,000 and 5,200 m, while it peaked between 3,500 and 4,000 m at entire Ladakh level. Perhaps biotic factors such as grazing and precipitation are, respectively, important in generating this pattern at the single mountain and entire Ladakh. ?? 2011 The Author(s).

Radial growth of two dominant montane conifer tree species in response to climate change in North-Central China.

PubMed

Jiang, Yuan; Zhang, Wentao; Wang, Mingchang; Kang, Muyi; Dong, Manyu

2014-01-01

North-Central China is a region in which the air temperature has clearly increased for several decades. Picea meyeri and Larix principis-rupprechtii are the most dominant co-occurring tree species within the cold coniferous forest belt ranging vertically from 1800 m to 2800 m a.s.l. in this region. Based on a tree-ring analysis of 292 increment cores sampled from 146 trees at different elevations, this study aimed to examine if the radial growth of the two species in response to climate is similar, whether the responses are consistent along altitudinal gradients and which species might be favored in the future driven by the changing climate. The results indicated the following: (1) The two species grew in different rhythms at low and high elevation respectively; (2) Both species displayed inconsistent relationships between radial growth and climate data along altitudinal gradients. The correlation between radial growth and the monthly mean temperature in the spring or summer changed from negative at low elevation into positive at high elevation, whereas those between the radial growth and the total monthly precipitation displayed a change from positive into negative along the elevation gradient. These indicate the different influences of the horizontal climate and vertical mountainous climate on the radial growth of the two species; (3) The species-dependent different response to climate in radial growth appeared mainly in autumn of the previous year. The radial growth of L. principis-rupprechtii displayed negative responses both to temperature and to precipitation in the previous September, October or November, which was not observed in the radial growth of P. meyeri. (4) The radial growth of both species will tend to be increased at high elevation and limited at low elevation, and L. principis-rupprechtii might be more favored in the future, if the temperature keeps rising.

Altitudinal variation in age and body size in Yunnan pond frog (Pelophylax pleuraden).

PubMed

Lou, Shang Ling; Jin, Long; Liu, Yan Hong; Mi, Zhi Ping; Tao, Gang; Tang, Yu Mei; Liao, Wen Bo

2012-08-01

Large-scale systematic patterns of body size are a basic concern of evolutionary biology. Identifying body size variation along altitudinal gradients may help us to understand the evolution of life history of animals. In this study, we investigated altitudinal variation in body size, age and growth rate in Chinese endemic frog, Pelophylax pleuraden. Data sampled from five populations covering an altitudinal span of 1413 to 1935 m in Sichuan province revealed that body size from five populations did not co-vary with altitudes, not following Bergmann's rule. Average adult SVL differed significantly among populations in males, but not in females. For both sexes, average adult age differed significantly among populations. Post-metamorphic growth rate did not co-vary with altitude, and females grew faster than males in all populations. When controlling the effect of age, body size did not differ among populations in both sexes, suggesting that age did not affect variation in body size among populations. For females, there may be other factors, such as the allocation of energy between growth and reproduction, that eliminated the effect of age on body size. To our minds, the major reason of body size variation among populations in male frogs may be related to individual longevity. Our findings also suggest that factors other than age and growth rate may contribute to size differences among populations.

Altitudinal patterns and controls of trace metal distribution in soils of a remote high mountain, Southwest China.

PubMed

Li, Rui; Bing, Haijian; Wu, Yanhong; Zhou, Jun; Xiang, Zhongxiang

2018-02-01

The aim of this study is to reveal the effects of regional human activity on trace metal accumulation in remote alpine ecosystems under long-distance atmospheric transport. Trace metals (Cd, Pb, and Zn) in soils of the Mt. Luoji, Southwest China, were investigated along a large altitudinal gradient [2200-3850 m above sea level (a.s.l.)] to elaborate the key factors controlling their distribution by Pb isotopic composition and statistical models. The concentrations of Cd, Pb, and Zn in the surface soils (O and A horizons) were relatively low at the altitudes of 3500-3700 m a.s.l. The enrichment factors of trace metals in the surface soils increased with altitude. After normalization for soil organic matter, the concentrations of Cd still increased with altitude, whereas those of Pb and Zn did not show a clear altitudinal trend. The effects of vegetation and cold trapping (CTE) (pollutant enrichment by decreasing temperature with increasing altitude) mainly determined the distribution of Cd and Pb in the O horizon, whereas CTE and bedrock weathering (BW) controlled that of Zn. In the A horizon, the distribution of Cd and Pb depended on the vegetation regulation, whereas that of Zn was mainly related to BW. Human activity, including ores mining and fossil fuels combustion, increased the trace metal deposition in the surface soils. The anthropogenic percentage of Cd, Pb, and Zn quantified 92.4, 67.8, and 42.9% in the O horizon, and 74.5, 33.9, and 24.9% in the A horizon, respectively. The anthropogenic metals deposited at the high altitudes of Mt. Luoji reflected the impact of long-range atmospheric transport on this remote alpine ecosystem from southern and southwestern regions.

Phenological response of grassland species to manipulative snowmelt and drought along an altitudinal gradient.

PubMed

Cornelius, Christine; Leingärtner, Annette; Hoiss, Bernhard; Krauss, Jochen; Steffan-Dewenter, Ingolf; Menzel, Annette

2013-01-01

Plant communities in the European Alps are assumed to be highly affected by climate change, as the temperature rise in this region is above the global average. It is predicted that higher temperatures will lead to advanced snowmelt dates and that the number of extreme weather events will increase. The aims of this study were to determine the impacts of extreme climatic events on flower phenology and to assess whether those impacts differed between lower and higher altitudes. In 2010, an experiment simulating advanced and delayed snowmelt as well as a drought event was conducted along an altitudinal transect approximately every 250 m (600-2000 m above sea level) in the Berchtesgaden National Park, Germany. The study showed that flower phenology was strongly affected by altitude; however, there were few effects of the manipulative treatments on flowering. The effects of advanced snowmelt were significantly greater at higher than at lower sites, but no significant difference was found between both altitudinal bands for the other treatments. The response of flower phenology to temperature declined through the season and the length of flowering duration was not significantly influenced by treatments. The stronger effect of advanced snowmelt at higher altitudes may be a response to differences in treatment intensity across the gradient. Consequently, shifts in the date of snowmelt due to global warming may affect species more at higher than at lower altitudes, as changes may be more pronounced at higher altitudes. These data indicate a rather low risk of drought events on flowering phenology in the Bavarian Alps.

The roles of genetic drift and natural selection in quantitative trait divergence along an altitudinal gradient in Arabidopsis thaliana

PubMed Central

Luo, Y; Widmer, A; Karrenberg, S

2015-01-01

Understanding how natural selection and genetic drift shape biological variation is a central topic in biology, yet our understanding of the agents of natural selection and their target traits is limited. We investigated to what extent selection along an altitudinal gradient or genetic drift contributed to variation in ecologically relevant traits in Arabidopsis thaliana. We collected seeds from 8 to 14 individuals from each of 14 A. thaliana populations originating from sites between 800 and 2700 m above sea level in the Swiss Alps. Seed families were grown with and without vernalization, corresponding to winter-annual and summer-annual life histories, respectively. We analyzed putatively neutral genetic divergence between these populations using 24 simple sequence repeat markers. We measured seven traits related to growth, phenology and leaf morphology that are rarely reported in A. thaliana and performed analyses of altitudinal clines, as well as overall QST-FST comparisons and correlation analyses among pair-wise QST, FST and altitude of origin differences. Multivariate analyses suggested adaptive differentiation along altitude in the entire suite of traits, particularly when expressed in the summer-annual life history. Of the individual traits, a decrease in rosette leaf number in the vegetative state and an increase in leaf succulence with increasing altitude could be attributed to adaptive divergence. Interestingly, these patterns relate well to common within- and between-species trends of smaller plant size and thicker leaves at high altitude. Our results thus offer exciting possibilities to unravel the underlying mechanisms for these conspicuous trends using the model species A. thaliana. PMID:25293874

Altitudinal patterns in breeding bird species richness and density in relation to climate, habitat heterogeneity, and migration influence in a temperate montane forest (South Korea).

PubMed

Kim, Jin-Yong; Lee, Sanghun; Shin, Man-Seok; Lee, Chang-Hoon; Seo, Changwan; Eo, Soo Hyung

2018-01-01

Altitudinal patterns in the population ecology of mountain bird species are useful for predicting species occurrence and behavior. Numerous hypotheses about the complex interactions among environmental factors have been proposed; however, these still remain controversial. This study aimed to identify the altitudinal patterns in breeding bird species richness or density and to test the hypotheses that climate, habitat heterogeneity (horizontal and vertical), and heterospecific attraction in a temperate forest, South Korea. We conducted a field survey of 142 plots at altitudes between 200 and 1,400 m a.s.l in the breeding season. A total of 2,771 individuals from 53 breeding bird species were recorded. Altitudinal patterns of species richness and density showed a hump-shaped pattern, indicating that the highest richness and density could be observed at moderate altitudes. Models constructed with 13 combinations of six variables demonstrated that species richness was positively correlated with vertical and horizontal habitat heterogeneity. Density was positively correlated with vertical, but not horizontal habitat heterogeneity, and negatively correlated with migratory bird ratio. No significant relationships were found between spring temperature and species richness or density. Therefore, the observed patterns in species richness support the hypothesis that habitat heterogeneity, rather than climate, is the main driver of species richness. Also, neither habitat heterogeneity nor climate hypotheses fully explains the observed patterns in density. However, vertical habitat heterogeneity does likely help explain observed patterns in density. The heterospecific attraction hypothesis did not apply to the distribution of birds along the altitudinal gradient. Appropriate management of vertical habitat heterogeneity, such as vegetation cover, should be maintained for the conservation of bird diversity in this area.

Structure, composition and regeneration of riparian forest along an altitudinal gradient in northern Iran

Treesearch

Mohammad Naghi Adel; Hassan Pourbabaei; Ali Salehi; Seyed Jalil Alavi; Daniel C. Dey

2017-01-01

In order to protect and understand the regeneration of riparian forests, it is important to understand the environmental conditions that lead to their vegetation differentiation. We evaluated the structure, composition, density and regeneration of woody species in forests along the river Safaroud in Ramsar forest in northern Iran in relation to elevation, soil...

Altitudinal gradients of bryophyte diversity and community assemblage in southern Appalachian spruce-fir forests

Treesearch

Sarah E. Stehn; Christopher R. Webster; Janice M. Glime; Michael A. Jenkins

2010-01-01

Ground-layer plant communities in spruce-fir forests of the southern Appalachians have likely undergone significant change since the widespread death of canopy Fraser fir (Abies fraseri) caused by the exotic balsam woolly adelgid (Adelges piceae). Bryophytes comprise an important part of the ground-layer flora in the spruce-fir...

Experimental evidence for herbivore limitation of the treeline.

PubMed

Speed, James D M; Austrheim, Gunnar; Hester, Alison J; Mysterud, Atle

2010-11-01

The treeline ecotone divides forest from open alpine or arctic vegetation states. Treelines are generally perceived to be temperature limited. The role of herbivores in limiting the treeline is more controversial, as experimental evidence from relevant large scales is lacking. Here we quantify the impact of different experimentally controlled herbivore densities on the recruitment and survival of birch Betula pubescens tortuosa along an altitudinal gradient in the mountains of southern Norway. After eight years of summer grazing in large-scale enclosures at densities of 0, 25, and 80 sheep/km2, birch recruited within the whole altitudinal range of ungrazed enclosures, but recruitment was rarer in enclosures with low-density sheep and was largely limited to within the treeline in enclosures with high-density sheep. In contrast, the distribution of saplings (birch older than the experiment) did not differ between grazing treatments, suggesting that grazing sheep primarily limit the establishment of new tree recruits rather than decrease the survival of existing individuals. This study provides direct experimental evidence that herbivores can limit the treeline below its potential at the landscape scale and even at low herbivore densities in this climatic zone. Land use changes should thus be considered in addition to climatic changes as potential drivers of ecotone shifts.

Ontogenetic resource-use strategies in a rare long-lived cycad along environmental gradients

PubMed Central

Álvarez-Yépiz, Juan C.; Cueva, Alejandro; Dovčiak, Martin; Teece, Mark; Yepez, Enrico A.

2014-01-01

Functional traits can drive plant responses to short- and long-term stressful conditions, with potential effects on species persistence in local habitats, changes in population size and structure, and potential species range shifts in changing environments. We investigated whether ecophysiological traits in a rare cycad vary along environmental gradients and with ontogeny to understand intra-specific resource-use variation (e.g. symbiotic nitrogen fixation, nitrogen- and water-use efficiency) and possible species adaptations for different environments. Environmental gradients were characterized with 14 soil and topographic variables. Nitrogen- and water-use efficiency improved with ontogeny (from seedling to juvenile and adult stages) but declined as soil fertility decreased with increasing elevation. Conversely, reliance on symbiotic nitrogen fixation increased with elevation and varied slightly with ontogeny. Improved water-use efficiency at lower elevation and nitrogen fixation at higher elevation may represent key functional strategies for maintaining the lower and upper altitudinal species range limits, especially in arid environments where stressful conditions are intensifying due to climatic and land-use changes. In addition to facilitation linked to the regeneration niche, improved resource-use efficiency linked to the adult niche may strongly influence cycad distribution and persistence in contemporary environments. A functional approach to conservation of rare or endangered plant species may be needed in order to target the most sensitive stages to changing environmental conditions and to better understand potential range shifts and adaptive responses to global land-use and climate changes. PMID:27293655

Evidence of high-elevation amplification versus Arctic amplification

NASA Astrophysics Data System (ADS)

Wang, Qixiang; Fan, Xiaohui; Wang, Mengben

2016-01-01

Elevation-dependent warming in high-elevation regions and Arctic amplification are of tremendous interest to many scientists who are engaged in studies in climate change. Here, using annual mean temperatures from 2781 global stations for the 1961-2010 period, we find that the warming for the world’s high-elevation stations (>500 m above sea level) is clearly stronger than their low-elevation counterparts; and the high-elevation amplification consists of not only an altitudinal amplification but also a latitudinal amplification. The warming for the high-elevation stations is linearly proportional to the temperature lapse rates along altitudinal and latitudinal gradients, as a result of the functional shape of Stefan-Boltzmann law in both vertical and latitudinal directions. In contrast, neither altitudinal amplification nor latitudinal amplification is found within the Arctic region despite its greater warming than lower latitudes. Further analysis shows that the Arctic amplification is an integrated part of the latitudinal amplification trend for the low-elevation stations (≤500 m above sea level) across the entire low- to high-latitude Northern Hemisphere, also a result of the mathematical shape of Stefan-Boltzmann law but only in latitudinal direction.

Evidence of high-elevation amplification versus Arctic amplification

PubMed Central

Wang, Qixiang; Fan, Xiaohui; Wang, Mengben

2016-01-01

Elevation-dependent warming in high-elevation regions and Arctic amplification are of tremendous interest to many scientists who are engaged in studies in climate change. Here, using annual mean temperatures from 2781 global stations for the 1961–2010 period, we find that the warming for the world’s high-elevation stations (>500 m above sea level) is clearly stronger than their low-elevation counterparts; and the high-elevation amplification consists of not only an altitudinal amplification but also a latitudinal amplification. The warming for the high-elevation stations is linearly proportional to the temperature lapse rates along altitudinal and latitudinal gradients, as a result of the functional shape of Stefan-Boltzmann law in both vertical and latitudinal directions. In contrast, neither altitudinal amplification nor latitudinal amplification is found within the Arctic region despite its greater warming than lower latitudes. Further analysis shows that the Arctic amplification is an integrated part of the latitudinal amplification trend for the low-elevation stations (≤500 m above sea level) across the entire low- to high-latitude Northern Hemisphere, also a result of the mathematical shape of Stefan-Boltzmann law but only in latitudinal direction. PMID:26753547

Nutrient cycling in Nothofagus pumilio forests along an altitudinal gradient in Tierra del Fuego, Argentina

Treesearch

Jorge L. Frangi; Marcelo D. Barrera; Laura L. Richter; Ariel E. Lugo

2005-01-01

Nothofagus pumilio (lenga) forests form monocultures from sea level to timberline in Tierra de Fuego, Argentina. Past studies suggested that the life form change from erect forest to krummholz had advantages to forest function. Aboveground net primary productivity (NPP) and organic matter production per unit leaf area and growing season day were higher in krummholz...

Indian Ocean dipole and rainfall drive a Moran effect in East Africa malaria transmission.

PubMed

Chaves, Luis Fernando; Satake, Akiko; Hashizume, Masahiro; Minakawa, Noboru

2012-06-15

Patterns of concerted fluctuation in populations-synchrony-can reveal impacts of climatic variability on disease dynamics. We examined whether malaria transmission has been synchronous in an area with a common rainfall regime and sensitive to the Indian Ocean Dipole (IOD), a global climatic phenomenon affecting weather patterns in East Africa. We studied malaria synchrony in 5 15-year long (1984-1999) monthly time series that encompass an altitudinal gradient, approximately 1000 m to 2000 m, along Lake Victoria basin. We quantified the association patterns between rainfall and malaria time series at different altitudes and across the altitudinal gradient encompassed by the study locations. We found a positive seasonal association of rainfall with malaria, which decreased with altitude. By contrast, IOD and interannual rainfall impacts on interannual disease cycles increased with altitude. Our analysis revealed a nondecaying synchrony of similar magnitude in both malaria and rainfall, as expected under a Moran effect, supporting a role for climatic variability on malaria epidemic frequency, which might reflect rainfall-mediated changes in mosquito abundance. Synchronous malaria epidemics call for the integration of knowledge on the forcing of malaria transmission by environmental variability to develop robust malaria control and elimination programs.

Genome size variation in wild and cultivated maize along altitudinal gradients

PubMed Central

Díez, Concepción M.; Gaut, Brandon S.; Meca, Esteban; Scheinvar, Enrique; Montes-Hernandez, Salvador; Eguiarte, Luis E.; Tenaillon, Maud I.

2014-01-01

Summary • It is still an open question as to whether genome size (GS) variation is shaped by natural selection. One approach to address this question is a population-level survey that assesses both the variation in GS and the relationship of GS to ecological variants. • We assessed GS in Zea mays, a species that includes the cultivated crop, maize, and its closest wild relatives, the teosintes. We measured GS in five plants of each of 22 maize landraces and 21 teosinte populations from Mexico sampled from parallel altitudinal gradients. • GS was significantly smaller in landraces than in teosintes, but the largest component of GS variation was among landraces and among populations. In maize, GS correlated negatively with altitude; more generally, the best GS predictors were linked to geography. By contrast, GS variation in teosintes was best explained by temperature and precipitation. • Overall, our results further document the size flexibility of the Zea genome, but also point to a drastic shift in patterns of GS variation since domestication. We argue that such patterns may reflect the indirect action of selection on GS, through a multiplicity of phenotypes and life-history traits. PMID:23550586

Population Fluctuation and Altitudinal Distribution of Tetraleurodes perseae (Nakahara) (Hemiptera: Aleyrodidae) in Avocado (Lauraceae) in Morelos, Mexico.

PubMed

García-Palacios, Daniel; Bautista-Martínez, Néstor; Lagunes-Tejeda, Ángel; Carrillo-Sánchez, José Luis; Nieto-Ángel, Daniel; García-Gutiérrez, Cipriano

2016-01-01

Although whiteflies Tetraleurodes perseae (Nakahara) (Hemiptera: Aleyrodidae) are considered a secondary pest of avocado crops, their presence and the damages that they cause can decrease crop vigor and affect production. The objective of the present work was to determine the population fluctuation and altitudinal distribution of the T. perseae Nakahara whitefly in avocado trees, as well as to determine the number of possible generations in one year. The study was done in three orchards in Morelos state, located at different altitudes, from February 2014 to April 2015. Samplings were done every 21 days from 10 randomly chosen trees in each orchard. The samples were taken randomly from the middle stratus (1.6 m in height) of each tree; in buds or young leaves for the number of adults and leaves only for nymphs. Additionally, two yellow traps (7 × 14 cm) with glue were placed in each tree for adult samplings. Data were collected regarding vegetative budding, rainfall, relative humidity, and temperature. T. perseae was present in all three sampled orchards, with a greater presence in the lowest orchard, during the whole study period. In the orchard with the lowest altitudinal gradient (1,736 masl), 11 whitefly generations developed; 10 generations developed in the medium gradient orchard (1,934 masl); and 8 generations developed in the highest orchard (2,230 masl). The adults showed a positive relationship with regard to vegetative buds, while the nymphs had a negative relationship with regard to relative humidity. The rest of the parameters showed diverse effects on the species depending on the altitude of the orchard. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America.

Population Fluctuation and Altitudinal Distribution of Tetraleurodes perseae (Nakahara) (Hemiptera: Aleyrodidae) in Avocado (Lauraceae) in Morelos, Mexico

PubMed Central

García-Palacios, Daniel; Bautista-Martínez, Néstor; Lagunes-Tejeda, Ángel; Carrillo-Sánchez, José Luis; Nieto-Ángel, Daniel; García-Gutiérrez, Cipriano

2016-01-01

Although whiteflies Tetraleurodes perseae (Nakahara) (Hemiptera: Aleyrodidae) are considered a secondary pest of avocado crops, their presence and the damages that they cause can decrease crop vigor and affect production. The objective of the present work was to determine the population fluctuation and altitudinal distribution of the T. perseae Nakahara whitefly in avocado trees, as well as to determine the number of possible generations in one year. The study was done in three orchards in Morelos state, located at different altitudes, from February 2014 to April 2015. Samplings were done every 21 days from 10 randomly chosen trees in each orchard. The samples were taken randomly from the middle stratus (1.6 m in height) of each tree; in buds or young leaves for the number of adults and leaves only for nymphs. Additionally, two yellow traps (7 × 14 cm) with glue were placed in each tree for adult samplings. Data were collected regarding vegetative budding, rainfall, relative humidity, and temperature. T. perseae was present in all three sampled orchards, with a greater presence in the lowest orchard, during the whole study period. In the orchard with the lowest altitudinal gradient (1,736 masl), 11 whitefly generations developed; 10 generations developed in the medium gradient orchard (1,934 masl); and 8 generations developed in the highest orchard (2,230 masl). The adults showed a positive relationship with regard to vegetative buds, while the nymphs had a negative relationship with regard to relative humidity. The rest of the parameters showed diverse effects on the species depending on the altitude of the orchard. PMID:27658809

Linking altitudinal gradients and temperature responses of plant phenology in the Bavarian Alps.

PubMed

Cornelius, C; Estrella, N; Franz, H; Menzel, A

2013-01-01

Global climate change influences ecosystems across the world. Alpine plant communities have already experienced serious impacts, and will continue to do so as climate change continues. The aim of our study was to determine the sensitivity of woody and herbaceous species to shifts in temperature along an altitudinal gradient. Since 1994, park rangers have been making phenological observations at 24 sites from 680 to 1425 m a.s.l. Each year 21 plant species were observed once or twice weekly from March to July; with a main focus on flowering and leaf unfolding. Our study showed a very high degree of dependence of phenophases and species on inter-annual temperature variation and altitude. Averaged over all species and phenophases, there was a delay of 3.8 days with every 100 m increase in altitude and, across all elevations, an advance of phenophases of 6 days per 1 °C increase in temperature. Temperature lapse rates assessed indirectly by phenology, as the quotient of altitudinal to temperature response coefficients, were higher than directly calculated from March to July mean temperatures, most likely due to snow effects. Furthermore, a significant difference in sensitivity to temperature change was found between growth forms (herbs versus trees). Sensitivity was less pronounced in events occurring later in the season. Our results show that species reactions will differ in magnitude during global warming. Consequently, impacts of shifts in the timing of phenological events on plant migration and plant-pollinator interactions due to rising temperatures should be considered at the species level. © 2012 German Botanical Society and The Royal Botanical Society of the Netherlands.

Dataset of MIGRAME Project (Global Change, Altitudinal Range Shift and Colonization of Degraded Habitats in Mediterranean Mountains)

PubMed Central

Pérez-Luque, Antonio Jesús; Zamora, Regino; Bonet, Francisco Javier; Pérez-Pérez, Ramón

2015-01-01

Abstract In this data paper, we describe the dataset of the Global Change, Altitudinal Range Shift and Colonization of Degraded Habitats in Mediterranean Mountains (MIGRAME) project, which aims to assess the capacity of altitudinal migration and colonization of marginal habitats by Quercus pyrenaica Willd. forests in Sierra Nevada (southern Spain) considering two global-change drivers: temperature increase and land-use changes. The dataset includes information of the forest structure (diameter size, tree height, and abundance) of the Quercus pyrenaica ecosystem in Sierra Nevada obtained from 199 transects sampled at the treeline ecotone, mature forest, and marginal habitats (abandoned cropland and pine plantations). A total of 3839 occurrence records were collected and 5751 measurements recorded. The dataset is included in the Sierra Nevada Global-Change Observatory (OBSNEV), a long-term research project designed to compile socio-ecological information on the major ecosystem types in order to identify the impacts of global change in this mountain range. PMID:26491387

Geographical and altitudinal distribution of Brachycephalus (Anura: Brachycephalidae) endemic to the Brazilian Atlantic Rainforest

PubMed Central

Firkowski, Carina R.; Belmonte-Lopes, Ricardo; Corrêa, Leandro; Ribeiro, Luiz F.; Morato, Sérgio A.A.; Antoniazzi-Jr., Reuber L.; Reinert, Bianca L.; Meyer, Andreas L.S.; Cini, Felipe A.; Pie, Marcio R.

2016-01-01

Mountains of the Brazilian Atlantic Forest can act as islands of cold and wet climate, leading to the isolation and speciation of species with low dispersal capacity, such as the toadlet species of the genus Brachycephalus. This genus is composed primarily by diurnal species, with miniaturized body sizes (<2.5 cm), inhabiting microhabitats in the leaf litter of montane forests. Still, little is known about the geographical distribution, altitudinal range, and ecological limits of most Brachycephalus species. In this study, we review the available data on the geographical and altitudinal distribution of Brachycephalus based on occurrence records compiled from literature and museums, both for the genus as a whole and separately for the three recently proposed groups of species (ephippium, didactylus, and pernix). The final ensemble dataset comprised 333 records, 120 localities, 28 described species, and six undescribed ones. Species were recorded in six relief units, the richest of which being the Serra do Mar, with 30 species. When the Serra do Mar is subdivided into three subunits, Northern, Central and Southern Serra do Mar, the number of species increase from north to the south, with records of six, nine, and 16 species, respectively. We were able to estimate the extent of occurrence of nearly half of the described species, and the resulting estimates indicate that many of them show remarkably small ranges, some of which less than 50 ha. Brachycephalus species are present from sea level to roughly 1,900 m a.s.l., with the highest richness being found between 751 and 1,000 m a.s.l. (21 spp.). The species with the broadest altitudinal range were B. didactylus (1,075 m) and Brachycephalus sp. 1 (1,035 m), both in the didactylus group, and B. ephippium (1,050 m), of the ephippium group. The broadest altitudinal amplitude for species of the pernix group was recorded for B. brunneus (535 m). The lowest altitudinal records for the pernix group were at 845 m a.s.l. in the state of Paraná and at 455 m a.s.l. in the state of Santa Catarina. The altitudinal occurrence in the pernixspecies group seems to decrease southward. Syntopy between species is also reviewed. PMID:27761312

Cross-continental comparison of the functional composition and carbon allocation of two altitudinal forest transects in Ecuador and Rwanda.

NASA Astrophysics Data System (ADS)

Bauters, Marijn; Bruneel, Stijn; Demol, Miro; Taveirne, Cys; Van Der Heyden, Dries; Boeckx, Pascal; Kearsley, Elizabeth; Cizungu, Landry; Verbeeck, Hans

2016-04-01

Tropical forests are key actors in the global carbon cycle. Predicting future responses of these forests to global change is challenging, but important for global climate models. However, our current understanding of such responses is limited, due to the complexity of forest ecosystems and the slow dynamics that inherently form these systems. Our understanding of ecosystem ecology and functioning could greatly benefit from experimental setups including strong environmental gradients in the tropics, as found on altitudinal transects. We setup two such transects in both South-America and Africa, focussing on shifts in carbon allocation, forest structure and functional composition. By a cross-continental comparison of both transects, we will gain insight in how different or alike both tropical forests biomes are in their responses, and how universal the observed adaption mechanisms are.

Assessing the vulnerability of traditional maize seed systems in Mexico to climate change.

PubMed

Bellon, Mauricio R; Hodson, David; Hellin, Jon

2011-08-16

Climate change is predicted to have major impacts on small-scale farmers in Mexico whose livelihoods depend on rain-fed maize. We examined the capacity of traditional maize seed systems to provide these farmers with appropriate genetic material under predicted agro-ecological conditions associated with climate change. We studied the structure and spatial scope of seed systems of 20 communities in four transects across an altitudinal gradient from 10-2,980 m above sea level in five states of eastern Mexico. Results indicate that 90% of all of the seed lots are obtained within 10 km of a community and 87% within an altitudinal range of ±50 m but with variation across four agro-climate environments: wet lowland, dry lowland, wet upper midlatitude, and highlands. Climate models suggest a drying and warming trend for the entire study area during the main maize season, leading to substantial shifts in the spatial distribution patterns of agro-climate environments. For all communities except those in the highlands, predicted future maize environments already are represented within the 10-km radial zones, indicating that in the future farmers will have easy access to adapted planting material. Farmers in the highlands are the most vulnerable and probably will need to acquire seed from outside their traditional geographical ranges. This change in seed sources probably will entail important information costs and the development of new seed and associated social networks, including improved linkages between traditional and formal seed systems and more effective and efficient seed-supply chains. The study has implications for analogous areas elsewhere in Mexico and around the world.

Divergent climate response on hydraulic-related xylem anatomical traits of Picea abies along a 900-m altitudinal gradient.

PubMed

Castagneri, Daniele; Petit, Giai; Carrer, Marco

2015-12-01

Climate change can induce substantial modifications in xylem structure and water transport capacity of trees exposed to environmental constraints. To elucidate mechanisms of xylem plasticity in response to climate, we retrospectively analysed different cell anatomical parameters over tree-ring series in Norway spruce (Picea abies L. Karst.). We sampled 24 trees along an altitudinal gradient (1200, 1600 and 2100 m above sea level, a.s.l.) and processed 2335 ± 1809 cells per ring. Time series for median cell lumen area (MCA), cell number (CN), tree-ring width (RW) and tree-ring-specific hydraulic conductivity (Kr) were crossed with daily temperature and precipitation records (1926-2011) to identify climate influence on xylem anatomical traits. Higher Kr at the low elevation site was due to higher MCA and CN. These variables were related to different aspects of intra-seasonal climatic variability under different environmental conditions, with MCA being more sensitive to summer precipitation. Winter precipitation (snow) benefited most parameters in all the sites. Descending the gradient, sensitivity of xylem features to summer climate shifted mostly from temperature to precipitation. In the context of climate change, our results indicate that higher summer temperatures at high elevations will benefit cell production and xylem hydraulic efficiency, whereas reduced water availability at lower elevations could negatively affect tracheids enlargement and thus stem capacity to transport water. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Contrasting patterns of population history and seed-mediated gene flow in two endemic Costa Rican oak species.

PubMed

Rodríguez-Correa, Hernando; Oyama, Ken; Quesada, Mauricio; Fuchs, Eric J; González-Rodríguez, Antonio

2018-03-02

Lower Central America is an important area to study recent population history and diversification of Neotropical species due to its complex and dynamic geology and climate. Phylogeographic studies in this region are few in comparison with other regions and even less for tree species. The aim of the present study was to characterize the phylogeographic structure in two partially co-distributed endemic oak species (Quercus costaricensis and Q. bumelioides) of the Costa Rican mountains using chloroplast short sequence repeats (cpSSRs), and to test for the effect of geological and palaeoclimatic processes on their population history. Genetic diversity and structure, haplotype networks, patterns of seed-mediated gene flow and historical demography were estimated for both species. Results suggested contrasting patterns. Quercus costaricensis exhibited high values of genetic diversity, a marked phylogeographic structure, a north-to-south genetic diversity gradient and evidence of a demographic expansion during the Quaternary. Quercus bumelioides did not show significant genetic structure and the haplotype network and historical demography estimates suggested a recent population expansion probably during the Pleistocene-Holocene transition. Phylogeographic structure of Q. costaricensis seems to be related to Pleistocene altitudinal migration due to its higher altitudinal distribution. Meanwhile, historical seed-mediated gene flow through the lower altitudinal distribution of Q. bumelioides may have promoted the homogenization of genetic variation. Population expansion and stable availability of suitable climatic areas in both species probably indicate that palaeoclimatic changes promoted downwards altitudinal migration and formation of continuous forests allowing oak species to expand their distribution into the Panamanian mountains during glacial stages.

Morphology of calcite crystals in clast coatings from four soils in the Mojave desert region

NASA Technical Reports Server (NTRS)

Chadwick, Oliver A.; Sowers, Janet M.; Amundson, Ronald G.

1989-01-01

Pedogenic calcite-crystal coatings on clasts were examined in four soils along an altitudinal gradient on Kyle Canyon alluvium in southern Nevada. Clast coatings were studied rather than matrix carbonate to avoid the effects of soil matrix on crystallization. Six crystal sizes and shapes were recognized and distinguished. Equant micrite was the dominant crystal form with similar abundance at all elevations. The distributions of five categories of spar and microspar appear to be influenced by altitudinally induced changes in effective moisture. In the drier, lower elevation soils, crystals were equant or parallel prismatic with irregular, interlocking boundaries while in the more moist, higher elevation soils they were randomly oriented, euhedral, prismatic, and fibrous. There was little support for the supposition that Mg(+2) substitution or increased (Mg + Ca)/HCO3 ratios in the precipitating solution produced crystal elongation.

The covariance between genetic and environmental influences across ecological gradients: reassessing the evolutionary significance of countergradient and cogradient variation.

PubMed

Conover, David O; Duffy, Tara A; Hice, Lyndie A

2009-06-01

Patterns of phenotypic change across environmental gradients (e.g., latitude, altitude) have long captivated the interest of evolutionary ecologists. The pattern and magnitude of phenotypic change is determined by the covariance between genetic and environmental influences across a gradient. Cogradient variation (CoGV) occurs when covariance is positive: that is, genetic and environmental influences on phenotypic expression are aligned and their joint influence accentuates the change in mean trait value across the gradient. Conversely, countergradient variation (CnGV) occurs when covariance is negative: that is, genetic and environmental influences on phenotypes oppose one another, thereby diminishing the change in mean trait expression across the gradient. CnGV has so far been found in at least 60 species, with most examples coming from fishes, amphibians, and insects across latitudinal or altitudinal gradients. Traits that display CnGV most often involve metabolic compensation, that is, the elevation of various physiological rates processes (development, growth, feeding, metabolism, activity) to counteract the dampening effect of reduced temperature, growing season length, or food supply. Far fewer examples of CoGV have been identified (11 species), and these most often involve morphological characters. Increased knowledge of spatial covariance patterns has furthered our understanding of Bergmann size clines, phenotypic plasticity, species range limits, tradeoffs in juvenile growth rate, and the design of conservation strategies for wild species. Moreover, temporal CnGV explains some cases of an apparent lack of phenotypic response to directional selection and provides a framework for predicting evolutionary responses to climate change.

A new species of Anacroneuria Klapálek 1909 (Plecoptera: Perlidae) and notes on the altitudinal distribution of the genus in Costa Rica.

PubMed

Gutiérrez-Fonseca, Pablo E; Springer, Monika

2015-12-18

Anacroneuria is the most widespread genus of Perlidae throughout the Neotropical region and 30 species have been reported from Costa Rica. In this paper, we describe and illustrate a new species from a high elevation cloud forest, A. quetzali sp.n., increasing to 31 the number of described species for Costa Rica. In addition, we examine the altitudinal distribution of Anacroneuria in Costa Rica to determine possible patterns, using the data available on its altitudinal range (10-2700 masl). We divided the elevational range in seven categories, using 500 m intervals. We found that most species (90.3%) are distributed in elevations that range from 500 to 1500 masl, followed by low-elevations (35.5%). Interestingly, despite the fact that Plecoptera are known to inhabit clean, fast flowing water at high elevations, only 16.1% of the species have been found at high elevations in Costa Rica (above 2000 masl). Thus, it seems that most Anacroneuria species are distributed in middle elevations, which are the areas that have a high diversity of freshwater habitats.

Madicolous Chironomidae from the Brazilian Atlantic Forest: a checklist with notes on altitudinal distributions (Diptera, Insecta)

PubMed Central

Shimabukuro, Erika Mayumi; Trivinho-Strixino, Susana

2018-01-01

Abstract Thin layers of water running over rocky surfaces are characteristic of madicolous habitats, which harbor a peculiar Chironomidae community. However, information on the identity, distribution, and ecology of madicolous chironomids in the Neotropical region are still sparse. The main purpose of this research is to reveal and contribute to the ecology of madicolous Chironomidae species, especially regarding their altitudinal distribution in the Atlantic Forest. Sampling was performed using our own designed emergence traps deployed from 0 to 2700 m a.s.l. in 70 sites in three mountains in southeastern Brazil. Sixty taxa of chironomids were collected and identified, of which only 22 are known to science. Most of the species showed a wider distribution than previously known, both in terms of geographic and altitudinal ranges, while others showed significant association with particular altitudinal bands (as evidenced by the indicator species analysis). Atlantic Forest mountainous regions are known to harbor one of the richest fauna in the world and have been suffering from several types of environmental impacts, including climate change, which will especially affect taxa living in specialized habitats. The narrow range of tolerance to environmental conditions verified for mountain species, and the fact that many of them are rare and endemic, make the conservation efforts in these areas indispensable. PMID:29706784

Plant Trait Variation along an Altitudinal Gradient in Mediterranean High Mountain Grasslands: Controlling the Species Turnover Effect

PubMed Central

Pescador, David S.; de Bello, Francesco; Valladares, Fernando; Escudero, Adrián

2015-01-01

Assessing changes in plant functional traits along gradients is useful for understanding the assembly of communities and their response to global and local environmental drivers. However, these changes may reflect the effects of species composition (i.e. composition turnover), species abundance (i.e. species interaction), and intra-specific trait variability (i.e. species plasticity). In order to determine the relevance of the latter, trait variation can be assessed under minimal effects of composition turnover. Nine sampling sites were established along an altitudinal gradient in a Mediterranean high mountain grassland community with low composition turnover (Madrid, Spain; 1940 m–2419 m). Nine functional traits were also measured for ten individuals of around ten plant species at each site, for a total of eleven species across all sites. The relative importance of different sources of variability (within/between site and intra-/inter-specific functional diversity) and trait variation at species and community level along the considered gradients were explored. We found a weak individual species response to altitude and other environmental variables although in some cases, individuals were smaller and leaves were thicker at higher elevations. This lack of species response was most likely due to greater within- than between-site species variation. At the community level, inter-specific functional diversity was generally greater than the intra-specific component except for traits linked to leaf element content (leaf carbon content, leaf nitrogen content, δ13C and δ15N). Inter-specific functional diversity decreased with lower altitude for four leaf traits (specific leaf area, leaf dry matter content, δ13C and δ15N), suggesting trait convergence between species at lower elevations, where water shortage may have a stronger environmental filtering effect than colder temperatures at higher altitudes. Our results suggest that, within a vegetation type encompassing various environmental gradients, both, changes in species abundance and intra-specific trait variability adjust for the community functional response to environmental changes. PMID:25774532

Plant trait variation along an altitudinal gradient in mediterranean high mountain grasslands: controlling the species turnover effect.

PubMed

Pescador, David S; de Bello, Francesco; Valladares, Fernando; Escudero, Adrián

2015-01-01

Assessing changes in plant functional traits along gradients is useful for understanding the assembly of communities and their response to global and local environmental drivers. However, these changes may reflect the effects of species composition (i.e. composition turnover), species abundance (i.e. species interaction), and intra-specific trait variability (i.e. species plasticity). In order to determine the relevance of the latter, trait variation can be assessed under minimal effects of composition turnover. Nine sampling sites were established along an altitudinal gradient in a Mediterranean high mountain grassland community with low composition turnover (Madrid, Spain; 1940 m-2419 m). Nine functional traits were also measured for ten individuals of around ten plant species at each site, for a total of eleven species across all sites. The relative importance of different sources of variability (within/between site and intra-/inter-specific functional diversity) and trait variation at species and community level along the considered gradients were explored. We found a weak individual species response to altitude and other environmental variables although in some cases, individuals were smaller and leaves were thicker at higher elevations. This lack of species response was most likely due to greater within- than between-site species variation. At the community level, inter-specific functional diversity was generally greater than the intra-specific component except for traits linked to leaf element content (leaf carbon content, leaf nitrogen content, δ13C and δ15N). Inter-specific functional diversity decreased with lower altitude for four leaf traits (specific leaf area, leaf dry matter content, δ13C and δ15N), suggesting trait convergence between species at lower elevations, where water shortage may have a stronger environmental filtering effect than colder temperatures at higher altitudes. Our results suggest that, within a vegetation type encompassing various environmental gradients, both, changes in species abundance and intra-specific trait variability adjust for the community functional response to environmental changes.

Assessing intraspecific variation in effective dispersal along an altitudinal gradient: a test in two Mediterranean high-mountain plants.

PubMed

Lara-Romero, Carlos; Robledo-Arnuncio, Juan J; García-Fernández, Alfredo; Iriondo, Jose M

2014-01-01

Plant recruitment depends among other factors on environmental conditions and their variation at different spatial scales. Characterizing dispersal in contrasting environments may thus be necessary to understand natural intraspecific variation in the processes underlying recruitment. Silene ciliata and Armeria caespitosa are two representative species of cryophilic pastures above the tree line in Mediterranean high mountains. No explicit estimations of dispersal kernels have been made so far for these or other high-mountain plants. Such data could help to predict their dispersal and recruitment patterns in a context of changing environments under ongoing global warming. We used an inverse modelling approach to analyse effective seed dispersal patterns in five populations of both Silene ciliata and Armeria caespitosa along an altitudinal gradient in Sierra de Guadarrama (Madrid, Spain). We considered four commonly employed two-dimensional seedling dispersal kernels exponential-power, 2Dt, WALD and log-normal. No single kernel function provided the best fit across all populations, although estimated mean dispersal distances were short (<1 m) in all cases. S. ciliata did not exhibit significant among-population variation in mean dispersal distance, whereas significant differences in mean dispersal distance were found in A. caespitosa. Both S. ciliata and A. caespitosa exhibited among-population variation in the fecundity parameter and lacked significant variation in kernel shape. This study illustrates the complexity of intraspecific variation in the processes underlying recruitment, showing that effective dispersal kernels can remain relatively invariant across populations within particular species, even if there are strong variations in demographic structure and/or physical environment among populations, while the invariant dispersal assumption may not hold for other species in the same environment. Our results call for a case-by-case analysis in a wider range of plant taxa and environments to assess the prevalence and magnitude of intraspecific dispersal variation.

Assessment of projected climate change in the Carpathian Region using the Holdridge life zone system

NASA Astrophysics Data System (ADS)

Szelepcsényi, Zoltán; Breuer, Hajnalka; Kis, Anna; Pongrácz, Rita; Sümegi, Pál

2018-01-01

In this paper, expected changes in the spatial and altitudinal distribution patterns of Holdridge life zone (HLZ) types are analysed to assess the possible ecological impacts of future climate change for the Carpathian Region, by using 11 bias-corrected regional climate model simulations of temperature and precipitation. The distribution patterns of HLZ types are characterized by the relative extent, the mean centre and the altitudinal range. According to the applied projections, the following conclusions can be drawn: (a) the altitudinal ranges are likely to expand in the future, (b) the lower and upper altitudinal limits as well as the altitudinal midpoints may move to higher altitudes, (c) a northward shift is expected for most HLZ types and (d) the magnitudes of these shifts can even be multiples of those observed in the last century. Related to the northward shifts, the HLZ types warm temperate thorn steppe and subtropical dry forest can also appear in the southern segment of the target area. However, a large uncertainty in the estimated changes of precipitation patterns was indicated by the following: (a) the expected change in the coverage of the HLZ type cool temperate steppe is extremely uncertain because there is no consensus among the projections even in terms of the sign of the change (high inter-model variability) and (b) a significant trend in the westward/eastward shift is simulated just for some HLZ types (high temporal variability). Finally, it is important to emphasize that the uncertainty of our results is further enhanced by the fact that some important aspects (e.g. seasonality of climate variables, direct CO2 effect, etc.) cannot be considered in the estimating process.

Soil-atmosphere exchange of nitrous oxide, methane and carbon dioxide in a gradient of elevation in the coastal Brazilian Atlantic forest

Treesearch

E. Sousa Neto; J.B. Carmo; Michael Keller; S.C. Martins; L.F. Alves; S.A. Vieira; M.C. Piccolo; P. Camargo; H.T.Z. Couto; C.A. Joly; L.A. Martinelli

2011-01-01

Soils of tropical forests are important to the global budgets of greenhouse gases. The Brazilian Atlantic Forest is the second largest tropical moist forest area of South America, after the vast Amazonian domain. This study aimed to investigate the emissions of nitrous oxide (N2O), carbon dioxide (CO2) and methane (CH4) fluxes along an altitudinal transect and the...

Altitudinal vs Latitudinal Climactic Drivers: A Comparison of a Relict Picea and Abies Forest in the Southern Appalachians versus the Hemi-Boreal Transition Zone off Southern Canada

NASA Astrophysics Data System (ADS)

Evans, A.; Lafon, C. W.

2015-12-01

Identification of biotic and abiotic determinants of tree species range limits is critical for understanding the effects of climate change on species distributions. Upward shifts of species distributions in montane areas have been widely reported but there have been few reports of latitudinal range retractions. Previous studies have indicated that southern latitudinal limits of a species range are dictated by biotic factors such as competition while others have suggested that abiotic factors, such as temperature, dictate these limits. We investigated the potential climatic gradients at the southern latitudinal limit of the Spruce (Picea) and Fir (Abies) species that dominate the Canadian boreal forest community as well as relict boreal forests containing similar species found in the high elevation areas of the Southern Appalachians. Existing research has suggested that relict ecosystems are more sensitive to climate change and can be indicative of future changes at latitudinal range limits. Expanding on this literature, we hypothesized that we would see similar gradients in climatic variables at the southern latitudinal limit of the Canadian boreal forest and those in the relict boreal forests southern Appalachians acting as controlling factors of these species distributions. We used forty years of climate data from weather stations along the southern edge of the boreal forest in the Canadian Shield provinces, species distribution data from the Canadian National Forest Inventory, (CNFI) geospatial data from the National Park Service (NPS), and historical weather data from the National Oceanic and Atmospheric Administration (NOAA) to perform our analysis. Our results indicate different climate variables act as controls of warm edge range limits of the Canadian boreal forest than those of the relict boreal forest of the southern Appalachians. However, we believe range retractions of the relict forest may be indicative of a more gradual response of similar species across a latitudinal gradient.

Assessing the vulnerability of traditional maize seed systems in Mexico to climate change

PubMed Central

Bellon, Mauricio R.; Hodson, David; Hellin, Jon

2011-01-01

Climate change is predicted to have major impacts on small-scale farmers in Mexico whose livelihoods depend on rain-fed maize. We examined the capacity of traditional maize seed systems to provide these farmers with appropriate genetic material under predicted agro-ecological conditions associated with climate change. We studied the structure and spatial scope of seed systems of 20 communities in four transects across an altitudinal gradient from 10–2,980 m above sea level in five states of eastern Mexico. Results indicate that 90% of all of the seed lots are obtained within 10 km of a community and 87% within an altitudinal range of ±50 m but with variation across four agro-climate environments: wet lowland, dry lowland, wet upper midlatitude, and highlands. Climate models suggest a drying and warming trend for the entire study area during the main maize season, leading to substantial shifts in the spatial distribution patterns of agro-climate environments. For all communities except those in the highlands, predicted future maize environments already are represented within the 10-km radial zones, indicating that in the future farmers will have easy access to adapted planting material. Farmers in the highlands are the most vulnerable and probably will need to acquire seed from outside their traditional geographical ranges. This change in seed sources probably will entail important information costs and the development of new seed and associated social networks, including improved linkages between traditional and formal seed systems and more effective and efficient seed-supply chains. The study has implications for analogous areas elsewhere in Mexico and around the world. PMID:21825131

A comparative analysis reveals weak relationships between ecological factors and beta diversity of stream insect metacommunities at two spatial levels.

PubMed

Heino, Jani; Melo, Adriano S; Bini, Luis Mauricio; Altermatt, Florian; Al-Shami, Salman A; Angeler, David G; Bonada, Núria; Brand, Cecilia; Callisto, Marcos; Cottenie, Karl; Dangles, Olivier; Dudgeon, David; Encalada, Andrea; Göthe, Emma; Grönroos, Mira; Hamada, Neusa; Jacobsen, Dean; Landeiro, Victor L; Ligeiro, Raphael; Martins, Renato T; Miserendino, María Laura; Md Rawi, Che Salmah; Rodrigues, Marciel E; Roque, Fabio de Oliveira; Sandin, Leonard; Schmera, Denes; Sgarbi, Luciano F; Simaika, John P; Siqueira, Tadeu; Thompson, Ross M; Townsend, Colin R

2015-03-01

The hypotheses that beta diversity should increase with decreasing latitude and increase with spatial extent of a region have rarely been tested based on a comparative analysis of multiple datasets, and no such study has focused on stream insects. We first assessed how well variability in beta diversity of stream insect metacommunities is predicted by insect group, latitude, spatial extent, altitudinal range, and dataset properties across multiple drainage basins throughout the world. Second, we assessed the relative roles of environmental and spatial factors in driving variation in assemblage composition within each drainage basin. Our analyses were based on a dataset of 95 stream insect metacommunities from 31 drainage basins distributed around the world. We used dissimilarity-based indices to quantify beta diversity for each metacommunity and, subsequently, regressed beta diversity on insect group, latitude, spatial extent, altitudinal range, and dataset properties (e.g., number of sites and percentage of presences). Within each metacommunity, we used a combination of spatial eigenfunction analyses and partial redundancy analysis to partition variation in assemblage structure into environmental, shared, spatial, and unexplained fractions. We found that dataset properties were more important predictors of beta diversity than ecological and geographical factors across multiple drainage basins. In the within-basin analyses, environmental and spatial variables were generally poor predictors of variation in assemblage composition. Our results revealed deviation from general biodiversity patterns because beta diversity did not show the expected decreasing trend with latitude. Our results also call for reconsideration of just how predictable stream assemblages are along ecological gradients, with implications for environmental assessment and conservation decisions. Our findings may also be applicable to other dynamic systems where predictability is low.

Pollen-based reconstruction of vegetational and climatic change over the past ~30 ka at Shudu Lake in the Hengduan Mountains of Yunnan, southwestern China.

PubMed

Yao, Yi-Feng; Song, Xiao-Yan; Wortley, Alexandra H; Wang, Yu-Fei; Blackmore, Stephen; Li, Cheng-Sen

2017-01-01

The Hengduan Mountains, with a distinct altitudinal differentiation and strong vertical vegetation zonation, occupy an important position in southwestern China as a global hotspot of biodiversity. Pollen analysis of lake sediments sampled along an altitudinal gradient in this region helps us to understand how this vegetation zonation arose and how it has responded to climate change and human impacts through time. Here we present a ~30-ka pollen record and interpret it in terms of vegetational and climatic change from a 310 cm-long core from Shudu Lake, located in the Hengduan Mountains region. Our results suggest that from 30 to 22 cal. ka BP, the vegetation was dominated by steppe/grassland (comprising mainly Artemisia, Poaceae and Polygonaceae) and broad-leaved forest (primarily Quercus, Betula and Castanopsis) in the lake catchment, reflecting a relatively warm, wet climate early in this phase and slightly warmer, drier conditions late in the phase. The period between 22 and 13.9 cal. ka BP was marked by a large expansion of needle- and broad-leaved mixed forest (Pinus, Abies and Quercus) and a decline in the extent of steppe/grassland, indicating warming, drying climatic conditions followed by a cold, wet period. Between 13.9 and 3 cal. ka BP, steppe/grassland expanded and the area covered by needle- and broad-leaved mixed forest reduced, implying a fluctuating climate dominated by warm and humid conditions. After 3 cal. ka BP, the vegetation was characterized by an increase in needle-leaved forest and reduction in steppe/grassland, suggesting warming and drying climate. A synthesis of palynological investigations from this and other sites suggests that the vegetation succession patterns seen along an altitudinal gradient in northwestern Yunnan since the Late Pleistocene are comparable, but that each site has its own characteristics probably due to the influences of altitude, topography, microclimate and human impact.

Effect of altitude on seasonal flight activity of Rhagoletis cerasi flies (Diptera: Tephritidae).

PubMed

Kovanci, O B; Kovanci, B

2006-08-01

The effect of altitudinal variation on the seasonal flight activity of Rhagoletis cerasi (Linnaeus) flies was evaluated along an altitudinal gradient from 150 to 1170 m in Mount Uludag, northwestern Turkey. The predicted dates of fly emergence, flight duration and dates of 5%, 50% and 95% cumulative fly catches at various altitudes were estimated from a degree-day model. Degree-day predictions were compared with those obtained from observations made with yellow sticky traps. The observed and predicted dates of appearance of adults were delayed by 1.4 and 2.0 days for every 100 m increase in altitude, respectively. The delay in phenology events was less at high altitudes than postulated by Hopkins' bioclimatic law, whether observed or predicted. The average absolute difference in predicted and observed dates of cumulative percentage catch of adults was 4.9 and 3.0 days in 1997 and 1998, respectively, but these differences were not significant. Prolonged flight activity was predicted and observed at higher altitudes, but the flight period lasted significantly longer than predicted. The observed flight period varied from 29 to 43 days in 1997 and from 36 to 52 days in 1998 between the lowest and highest altitude on the transect. Altitudinal variation between geographically close locations should be taken into account to properly time monitoring activities and hence to manage R. cerasi populations more effectively.

Arbuscular mycorrhizal fungal community composition affected by original elevation rather than translocation along an altitudinal gradient on the Qinghai-Tibet Plateau

NASA Astrophysics Data System (ADS)

Yang, Wei; Zheng, Yong; Gao, Cheng; Duan, Ji-Chuang; Wang, Shi-Ping; Guo, Liang-Dong

2016-11-01

Elucidating arbuscular mycorrhizal (AM) fungal responses to elevation changes is critical to improve understanding of microbial function in ecosystems under global asymmetrical climate change scenarios. Here we examined AM fungal community in a two-year reciprocal translocation of vegetation-intact soil blocks along an altitudinal gradient (3,200 m to 3,800 m) in an alpine meadow on the Qinghai-Tibet Plateau. AM fungal spore density was significantly higher at lower elevation than at higher elevation regardless of translocation, except that this parameter was significantly increased by upward translocation from original 3,200 m to 3,400 m and 3,600 m. Seventy-three operational taxonomic units (OTUs) of AM fungi were recovered using 454-pyrosequencing of 18S rDNA sequences at a 97% sequence similarity. Original elevation, downward translocation and upward translocation did not significantly affect AM fungal OTU richness. However, with increasing altitude the OTU richness of Acaulosporaceae and Ambisporaceae increased, but the OTU richness of Gigasporaceae and Glomeraceae decreased generally. The AM fungal community composition was significantly structured by original elevation but not by downward translocation and upward translocation. Our findings highlight that compared with the short-term reciprocal translocation, original elevation is a stronger determinant in shaping AM fungal community in the Qinghai-Tibet alpine meadow.

Arbuscular mycorrhizal fungal community composition affected by original elevation rather than translocation along an altitudinal gradient on the Qinghai-Tibet Plateau.

PubMed

Yang, Wei; Zheng, Yong; Gao, Cheng; Duan, Ji-Chuang; Wang, Shi-Ping; Guo, Liang-Dong

2016-11-09

Elucidating arbuscular mycorrhizal (AM) fungal responses to elevation changes is critical to improve understanding of microbial function in ecosystems under global asymmetrical climate change scenarios. Here we examined AM fungal community in a two-year reciprocal translocation of vegetation-intact soil blocks along an altitudinal gradient (3,200 m to 3,800 m) in an alpine meadow on the Qinghai-Tibet Plateau. AM fungal spore density was significantly higher at lower elevation than at higher elevation regardless of translocation, except that this parameter was significantly increased by upward translocation from original 3,200 m to 3,400 m and 3,600 m. Seventy-three operational taxonomic units (OTUs) of AM fungi were recovered using 454-pyrosequencing of 18S rDNA sequences at a 97% sequence similarity. Original elevation, downward translocation and upward translocation did not significantly affect AM fungal OTU richness. However, with increasing altitude the OTU richness of Acaulosporaceae and Ambisporaceae increased, but the OTU richness of Gigasporaceae and Glomeraceae decreased generally. The AM fungal community composition was significantly structured by original elevation but not by downward translocation and upward translocation. Our findings highlight that compared with the short-term reciprocal translocation, original elevation is a stronger determinant in shaping AM fungal community in the Qinghai-Tibet alpine meadow.

Arbuscular mycorrhizal fungal community composition affected by original elevation rather than translocation along an altitudinal gradient on the Qinghai-Tibet Plateau

PubMed Central

Yang, Wei; Zheng, Yong; Gao, Cheng; Duan, Ji-Chuang; Wang, Shi-Ping; Guo, Liang-Dong

2016-01-01

Elucidating arbuscular mycorrhizal (AM) fungal responses to elevation changes is critical to improve understanding of microbial function in ecosystems under global asymmetrical climate change scenarios. Here we examined AM fungal community in a two-year reciprocal translocation of vegetation-intact soil blocks along an altitudinal gradient (3,200 m to 3,800 m) in an alpine meadow on the Qinghai-Tibet Plateau. AM fungal spore density was significantly higher at lower elevation than at higher elevation regardless of translocation, except that this parameter was significantly increased by upward translocation from original 3,200 m to 3,400 m and 3,600 m. Seventy-three operational taxonomic units (OTUs) of AM fungi were recovered using 454-pyrosequencing of 18S rDNA sequences at a 97% sequence similarity. Original elevation, downward translocation and upward translocation did not significantly affect AM fungal OTU richness. However, with increasing altitude the OTU richness of Acaulosporaceae and Ambisporaceae increased, but the OTU richness of Gigasporaceae and Glomeraceae decreased generally. The AM fungal community composition was significantly structured by original elevation but not by downward translocation and upward translocation. Our findings highlight that compared with the short-term reciprocal translocation, original elevation is a stronger determinant in shaping AM fungal community in the Qinghai-Tibet alpine meadow. PMID:27827400

Integrating the EMPD with an Alpine altitudinal training set to reconstruct climate variables in Holocene pollen records from high-altitude peat bogs

NASA Astrophysics Data System (ADS)

Furlanetto, Giulia; Badino, Federica; Brunetti, Michele; Champvillair, Elena; De Amicis, Mattia; Maggi, Valter; Pini, Roberta; Ravazzi, Cesare; Vallé, Francesca

2016-04-01

Temperatures and precipitation are the main environmental factors influencing vegetation and pollen production. Knowing the modern climate optima and tolerances of those plants represented in fossil assemblages and assuming that the relationships between plants and climate in the past are not dissimilar from the modern ones, fossil pollen records offer many descriptors to reconstruct past climate variables. The aim of our work is to investigate the potential of high-altitude pollen records from an Alpine peat bog (TBValter, close to the Ruitor Glacier, Western Italian Alps) for quantitative paleoclimate estimates. The idea behind is that high-altitude ecosystems are more sensitive to climate changes, especially to changes in July temperatures that severely affect the timberline ecotone. Meantime, we met with difficulties when considering the factors involved in pollen dispersal over a complex altitudinal mountain pattern, such as the Alps. We used the EMPD-European Modern Pollen Database (Davis et al., 2013) as modern training set to be compared with our high-altitude fossil site. The EMPD dataset is valuable in that it provides a large geographic coverage of main ecological and climate gradients (at sub-continental scale) but lacks in sampling of altitudinal gradients and high-altitude sites in the Alps. We therefore designed an independent altitudinal training set for the alpine valley hosting our fossil site. 27 sampling plots were selected along a 1700m-elevational transect. In a first step, each plot was provided with (i) 3 moss polsters collected following the guidelines provided by Cañellas-Boltà et al. (2009) and analyzed separately to account for differences in pollen deposition at small scale, (ii) morphometrical parameters obtained through a high-resolution DEM, and (iii) temperature and precipitation were estimated by means of weighted linear regression of the meteorological variable versus elevation, locally evaluated for each site (Brunetti et al., 2014), starting from a dense and quality-controlled observational dataset. In the most advanced step, we designed calibration functions using modern pollen and climate data stored in the EMPD and integrated with the 27 samples from the altitudinal training set. Regression and calibration method (LWWA) and MAT (Modern Analogue Technique) were used to reconstruct temperatures and precipitation. We applied the models to our fossil site to infer temperatures of the coldest (Tjan) and warmest (Tjul) months and the mean annual precipitation (Pann). Finally we compared our results with established climate proxy records (oxygen isotope records from ice cores, records of Alpine Glaciers fluctuations, stalagmites). This research is promoted by the CNR-DTA NextData Project. Brunetti et al., 2014. International Journal of Climatology 34, 1278-1296. Cañellas-Boltà et al., 2009. The Holocene 19(8), 1185-1200. Davis et al., 2013. Vegetation History and Archaeobotany 22, 521-530.

Wafer characteristics via reflectometry

DOEpatents

Sopori, Bhushan L.

2010-10-19

Various exemplary methods (800, 900, 1000, 1100) are directed to determining wafer thickness and/or wafer surface characteristics. An exemplary method (900) includes measuring reflectance of a wafer and comparing the measured reflectance to a calculated reflectance or a reflectance stored in a database. Another exemplary method (800) includes positioning a wafer on a reflecting support to extend a reflectance range. An exemplary device (200) has an input (210), analysis modules (222-228) and optionally a database (230). Various exemplary reflectometer chambers (1300, 1400) include radiation sources positioned at a first altitudinal angle (1308, 1408) and at a second altitudinal angle (1312, 1412). An exemplary method includes selecting radiation sources positioned at various altitudinal angles. An exemplary element (1650, 1850) includes a first aperture (1654, 1854) and a second aperture (1658, 1858) that can transmit reflected radiation to a fiber and an imager, respectfully.

Density and community structure of soil- and bark-dwelling microarthropods along an altitudinal gradient in a tropical montane rainforest.

PubMed

Illig, Jens; Norton, Roy A; Scheu, Stefan; Maraun, Mark

2010-09-01

Microarthropod communities in the soil and on the bark of trees were investigated along an elevation gradient (1,850, 2,000, 2,150, 2,300 m) in a tropical montane rain forest in southern Ecuador. We hypothesised that the density of microarthropods declines with depth in soil and increases with increasing altitude mainly due to the availability of resources, i.e. organic matter. In addition, we expected bark and soil communities to differ strongly, since the bark of trees is more exposed to harsher factors. In contrast to our hypothesis, the density of major microarthropod groups (Collembola, Oribatida, Gamasina, Uropodina) was generally low and decreased with altitude. However, as we predicted the density of each of the groups decreased with soil depth. Density of microarthropods on tree bark was lower than in soil. Overall, 43 species of oribatid mites were found, with the most abundant higher taxa being Poronota, pycnonotic Apheredermata, Mixonomata and Eupheredermata. The oribatid mite community on bark did not differ significantly from that in soil. The number of oribatid mite species declined with altitude (24, 23, 17 and 13 species at 1,850, 2,000, 2,150 and 2,300 m, respectively). Rarefaction curves indicate that overall about 50 oribatid mite species are to be expected along the studied altitudinal gradient. Results of this study indicate (1) that microarthropods may be limited by the quality of resources at high altitudes and by the amount of resources at deeper soil layers, and (2) that the bark of trees and the soil are habitats of similar quality for oribatid mites.

The Effect of Altitudinal Gradient on the Carbon and Nitrogen Dynamics in Coastal Atlantic Forest of Southeast Brazil

NASA Astrophysics Data System (ADS)

Piccolo, M. D.; Martins, S. C.; Camargo, P. B.; Almeida, D. Q.; Correa, L. O.; Carmo, J. B.; Martinelli, L. A.

2009-12-01

The Brazilian Atlantic forest is a vast heterogeneous region with 1.5 million km2, encompassing a large variety of forest physiognomies and compositions, containing large number of species. These forests are distributed in different topographic and climatic conditions, with high levels of precipitation. The rate of deforestation is high, approaching 350 km2 per year, showing be highly fragmented with a large number of species in extinction. The aim of this study was to understanding of the basic biogeochemistry functioning of the coastal Atlantic Forest. The study was carried out in São Paulo State, Brazil (23° 24' S and 45° 11' W). The studied areas were: Restinga Forest at sea level; Lowland Ombrophylus Dense Forest at 100m of altitude asl; Submontana Ombrophylus Dense Forest at 400m of altitude asl and; Montane Ombrophylus Dense Forest at 1000m of altitude asl. A sampling area of 1 ha in each phytophysiognomies was subdivided in contiguous sub-parcels (10 x 10m). The forest floor litter accumulated (0.06m2) was collected monthly (n=15), during 12 months, in each phytophysiognomies. Soils samples (0-0.05m depth) were collected (n=32) from square regular grids, 30m away from each other. Techniques of multivariate like principal components analysis (PCA) were used to determine correlations between the variable. The ordination graphs make possible to observe frequent of standards, representing a significant ratio of the variability of the data. The two first PCA axes cumulatively explained 60% of the total variance of the litter variables. Litter C and δ13C values were strongly influenced by altitude at 1000m. The N and δ15N of litter were influenced by altitude at 100 and 400m. The C/N relation was influenced by altitude at 0m. The lignin was elevated (p<0.01) at sea level in comparison with the other phytophysiognomies. The cellulose values did not vary significantly along the altitudinal gradient. Soil C and N concentrations progressively increased along the altitudinal gradient (p<0.01). Soil C:N ratio was significantly higher at 0m. The two first PCA axes cumulatively explained 76% of the total variance of the soil variables. Soil C and N contents were strongly influenced by altitude at 1000m and the C/N relation and sand were influenced by altitude 0m. It is also possible to observe that C, N and clay contents are inversely proportional to the soil sand fraction. This study showed that analysis of the principal components was useful in the grouping areas. The factors that explain differences along this gradient are not yet well known, but topography and the microclimate are appears to be the two main candidate factors regulating this nutritional variation of litter in the gradient.

Slow Response or No Response? Distinguishing Non-Climatic Range Limits from Demographic Inertia

NASA Astrophysics Data System (ADS)

Hillerislambers, J.; Anderegg, L. D. L.; Breckheimer, I.; Ford, K.; Kroiss, S.

2016-12-01

One of the greatest challenges ecologists face is forecasting how species distributions will respond to climate change. In general, species distributions have moved polewards and upslope with recent climate change (i.e. range shifts), supporting the assumption that range limits are climatically determined. However, studies also document a surprising number of species whose distributions have remained unchanged in the last 50-100 years, despite significant warming during that time period. This apparent lack of response to warming can arise for species whose range limits are determined by factors other than climate (e.g. species interactions) OR for long-lived, slow-growing, and/or dispersal-limited species whose range shifts are unable to keep pace with rapid climate change. Unfortunately, while these two possibilities are often difficult to distinguish, they have very different implications for the long-term viability of the species in question. Here, we use extensive demographic data for long-lived and slow-growing conifers collected across a large climatic gradient at Mount Rainier (WA, USA) to explore A) evidence for climatically determined range limits and B) the rate at which altitudinal distributions could shift in response to climate change in the region. In doing so, we highlight some of the complications we face in identifying whether species will be sensitive or resilient to climate change.

Storms drive altitudinal migration in a tropical bird

PubMed Central

Boyle, W. Alice; Norris, D. Ryan; Guglielmo, Christopher G.

2010-01-01

Although migration is a widespread and taxonomically diverse behaviour, the ecological factors shaping migratory behaviour are poorly understood. Like other montane taxa, many birds migrate along elevational gradients in the tropics. Forty years ago, Alexander Skutch postulated that severe storms could drive birds to migrate downhill. Here, we articulate a novel mechanism that could link storms to mortality risks via reductions in foraging time and provide, to our knowledge, the first tests of this hypothesis in the White-ruffed Manakin (Corapipo altera), a small partially migratory frugivore breeding on the Atlantic slope of Costa Rica. As predicted, variation in rainfall was associated with plasma corticosterone levels, fat stores, plasma metabolites and haematocrit. By collecting data at high and low elevation sites simultaneously, we also found that high-elevation residents were more adversely affected by storms than low elevation migrants. These results, together with striking temporal capture patterns of altitudinal migrants relative to storms, provide, to our knowledge, the first evidence that weather-related risks incurred by species requiring high food intake rates can explain altitudinal migrations of tropical animals. These findings resolve conflicting evidence for and against food limitation being important in the evolution of this behaviour, and highlight how endogenous and exogenous processes influence life-history trade-offs made by individuals in the wild. Because seasonal storms are a defining characteristic of most tropical ecosystems and rainfall patterns will probably change in ensuing decades, these results have important implications for understanding the ecology, evolution and conservation of tropical animals. PMID:20375047

Storms drive altitudinal migration in a tropical bird.

PubMed

Boyle, W Alice; Norris, D Ryan; Guglielmo, Christopher G

2010-08-22

Although migration is a widespread and taxonomically diverse behaviour, the ecological factors shaping migratory behaviour are poorly understood. Like other montane taxa, many birds migrate along elevational gradients in the tropics. Forty years ago, Alexander Skutch postulated that severe storms could drive birds to migrate downhill. Here, we articulate a novel mechanism that could link storms to mortality risks via reductions in foraging time and provide, to our knowledge, the first tests of this hypothesis in the White-ruffed Manakin (Corapipo altera), a small partially migratory frugivore breeding on the Atlantic slope of Costa Rica. As predicted, variation in rainfall was associated with plasma corticosterone levels, fat stores, plasma metabolites and haematocrit. By collecting data at high and low elevation sites simultaneously, we also found that high-elevation residents were more adversely affected by storms than low elevation migrants. These results, together with striking temporal capture patterns of altitudinal migrants relative to storms, provide, to our knowledge, the first evidence that weather-related risks incurred by species requiring high food intake rates can explain altitudinal migrations of tropical animals. These findings resolve conflicting evidence for and against food limitation being important in the evolution of this behaviour, and highlight how endogenous and exogenous processes influence life-history trade-offs made by individuals in the wild. Because seasonal storms are a defining characteristic of most tropical ecosystems and rainfall patterns will probably change in ensuing decades, these results have important implications for understanding the ecology, evolution and conservation of tropical animals.

Are cytological parameters of maize landraces (Zea mays ssp. mays) adapted along an altitudinal cline?

PubMed

Fourastié, María Florencia; Gottlieb, Alexandra Marina; Poggio, Lidia; González, Graciela Esther

2018-03-01

The Northwestern Argentina (NWA) highland region is one of the southernmost areas of native maize cultivation. We studied variations of different cytological parameters, such as DNA contents, presence/absence of B chromosomes (Bs), and number and sequence composition of heterochromatic knobs in ten accessions of four maize landraces growing along a broad altitudinal cline in NWA. The aim of this work was to assess variations in cytological parameters and their relationship with the crop altitude of cultivation, in an adaptive context. The A-DNA content of the A chromosome complements showed 40% of difference between the lowest (4.5 pg) and the highest (6.3 pg) 2C value. This variation could be attributed to differences in number and size of heterochromatic knobs. Fluorescent in situ hybridization studies revealed the sequence composition of each knob, with a higher proportion of knobs composed of 180-bp repeats rather than TR-1 repeats, in all accessions. We also found numerical polymorphisms and the highest frequency of Bs reported in maize to this date. These results lead us to propose that the frequencies and doses of Bs are influenced by the landrace genotypical make-up. The Bs might be maintained in higher frequencies in those accessions having lower heterochromatin content, so as to preserve an optimal nucleotype. Furthermore, selective forces acting along the altitudinal gradient might be modulating the cytological parameters studied, as suggested by the significant correlations found among them.

Extensive contemporary pollen-mediated gene flow in two herb species, Ranunculus bulbosus and Trifolium montanum, along an altitudinal gradient in a meadow landscape

PubMed Central

Matter, Philippe; Kettle, Chris J.; Ghazoul, Jaboury; Pluess, Andrea R.

2013-01-01

Background and Aims Genetic connectivity between plant populations allows for exchange and dispersal of adaptive genes, which can facilitate plant population persistence particularly in rapidly changing environments. Methods Patterns of historic gene flow, flowering phenology and contemporary pollen flow were investigated in two common herbs, Ranunculus bulbosus and Trifolium montanum, along an altitudinal gradient of 1200–1800 m a.s.l. over a distance of 1 km among five alpine meadows in Switzerland. Key Results Historic gene flow was extensive, as revealed by Fst values of 0·01 and 0·007 in R. bulbosus and T. montanum, respectively, by similar levels of allelic richness among meadows and by the grouping of all individuals into one genetic cluster. Our data suggest contemporary pollen flow is not limited across altitudes in either species but is more pronounced in T. montanum, as indicated by the differential decay of among-sibships correlated paternity with increasing spatial distance. Flowering phenology among meadows was not a barrier to pollen flow in T. montanum, as the large overlap between meadow pairs was consistent with the extensive pollen flow. The smaller flowering overlap among R. bulbosus meadows might explain the slightly more limited pollen flow detected. Conclusions High levels of pollen flow among altitudes in both R. bulbosus and T. montanum should facilitate exchange of genes which may enhance adaptive responses to rapid climate change. PMID:23408831

Soil carbon and nitrogen stocks in forests along an altitudinal gradient in the eastern Himalayas and a meta-analysis of global data.

PubMed

Tashi, Sonam; Singh, Balwant; Keitel, Claudia; Adams, Mark

2016-06-01

High-altitude soils potentially store a large pool of carbon (C) and nitrogen (N). The assessment of total C and N stocks in soils is vital to understanding the C and N dynamics in terrestrial ecosystems. In this study, we examined effects of altitude and forest composition on soil C and N along a transect from 317 to 3300 m a.s.l. in the eastern Himalayas. We used meta-analysis to establish the context for our results on the effects of altitude on soil C, including variation with depth. Total C and N contents of soils significantly increased with altitude, but decreased with soil depth. Carbon and N were similarly correlated with altitude and temperature, and temperature was seemingly the main driver of soil C along the altitudinal gradient. Altitude accounted for 73% of the variation in C and 47% of the variation in N stocks. Soil pH and cation exchange capacity were correlated with both soil C and N stocks. Increases in soil C and N stocks were related to forest composition, forest basal area as well as quantity of leaf litter that were in turn influenced by altitude and temperature. Concentrations of C in foliage increased by 2.1% for every 1000 m rise in altitude, while that in leaf litter increased by 2.3%. © 2016 John Wiley & Sons Ltd.

Density Dependence, Landscape, and Weather Impacts on Aquatic Aedes japonicus japonicus (Diptera: Culicidae) Abundance Along an Urban Altitudinal Gradient.

PubMed

Chaves, Luis Fernando; Moji, Kazuhiko

2018-02-28

The Asian Bush Mosquito, Aedes (Finlaya) japonicus japonicus (Theobald) is an important globally invasive mosquito species. In comparison with other major invasive mosquitoes, relatively little is known about Ae. j. japonicus population dynamics in the field. Here, we present results from a 54-biweek long study of Ae. j. japonicus abundance in ovitraps set across the altitudinal gradient of Mt. Konpira, Nagasaki, Japan. Spatially, we found that Ae. j. japonicus fourth instar larvae (Aj4il) were more abundant at the base and top of Mt. Konpira and in ovitraps with more platykurtic water temperature (WT) distributions. In contrast, we found that temporally Aj4il were more abundant when ovitrap WT was more leptokurtic with 2 weeks of lag, and with high relative humidity SD with 2 months of lag. We also found that Aj4il were unlikely present when ovitrap WT was below 12.41°C. Parameter estimates for the Ricker model suggested that Ae. j. japonicus population growth was under density-dependence regulation, with a stable population dynamics whose fluctuations were associated with changes in ovitrap WT kurtosis and demographic stochasticity. Our results suggest that Aj4il abundance is more sensitive to temperature changes in kurtosis than mean values, potentially limiting the predictive ability of Ae. j. japonicus niche models based on the increase of average temperatures with global warming, and suggesting this mosquito species has a relatively coarse-grained response to temperature changes.

The dynamics, transmission, and population impacts of avian malaria in native hawaiian birds: A modeling approach

USGS Publications Warehouse

Samuel, M.D.; Hobbelen, P.H.F.; Decastro, F.; Ahumada, J.A.; Lapointe, D.A.; Atkinson, C.T.; Woodworth, B.L.; Hart, P.J.; Duffy, D.C.

2011-01-01

We developed an epidemiological model of avian malaria (Plasmodium relictum) across an altitudinal gradient on the island of Hawaii that includes the dynamics of the host, vector, and parasite. This introduced mosquito-borne disease is hypothesized to have contributed to extinctions and major shifts in the altitudinal distribution of highly susceptible native forest birds. Our goal was to better understand how biotic and abiotic factors influence the intensity of malaria transmission and impact on susceptible populations of native Hawaiian forest birds. Our model illustrates key patterns in the malaria-forest bird system: high malaria transmission in low-elevation forests with minor seasonal or annual variation in infection;episodic transmission in mid-elevation forests with site-to-site, seasonal, and annual variation depending on mosquito dynamics;and disease refugia in high-elevation forests with only slight risk of infection during summer. These infection patterns are driven by temperature and rainfall effects on parasite incubation period and mosquito dynamics across an elevational gradient and the availability of larval habitat, especially in mid-elevation forests. The results from our model suggest that disease is likely a key factor in causing population decline or restricting the distribution of many susceptible Hawaiian species and preventing the recovery of other vulnerable species. The model also provides a framework for the evaluation of factors influencing disease transmission and alternative disease control programs, and to evaluate the impact of climate change on disease cycles and bird populations. ??2011 by the Ecological Society of America.

Greenhouse gas emissions and N turnover along an altitudinal gradient at Mt. Kilimanjaro, Tanzania.

NASA Astrophysics Data System (ADS)

Gütlein, Adrian; Gerschlauer, Friederike; Zistl-Schlingmann, Marcus; Dannenmann, Michael; Meier, Rudolf; Kolar, Alison; Butterbach-Bahl, Klaus; Kiese, Ralf

2016-04-01

Worldwide climate and land-use change force alterations in various ecosystem properties and functions such as diversity and activity of soil microbial communities which are responsible for biogeochemical processes like soil nitrogen (N) turnover and associated greenhouse gas (GHG) exchange. Tropical deforestation is highest in Africa and despite the importance of those ecosystems to global climate and biogeochemical cycles, data for greenhouse gas exchange is still rare (Serca et al., 1994, Werner et al., 2007) and no study regarding N turnover processes has been published yet. For that reason, we focused on seven different land-use types extending along an altitudinal gradient (950 -- 3880m) at Mt. Kilimanjaro, East Africa, covering (semi-) natural savanna, two montane forests and one afro alpine ecosystem, an extensive agroforest (homegarden) and an intensively managed coffee plantation. On all ecosystems we measured CO_2, CH4 and N_2O fluxes and gross rates of ammonification, nitrification, N immobilization, and dissimilatory nitrate reduction to ammonium (DNRA). GHG results reveal pronounced N_2O fluxes depending mainly on soil moisture and to a lesser extent on soil temperature. Emissions are highest during the rainy seasons while lowest at dry season conditions. The largest N_2O emissions are recognizable at Ocotea forest, most likely due to the generally higher SOC/ totN and wetter conditions favoring formation and emission of N_2O via denitrification. Soils of the studied ecosystems were a sink of atmospheric CH

Processes affecting altitudinal distribution of invasive Ageratina adenophora in western Himalaya: The role of local adaptation and the importance of different life-cycle stages

PubMed Central

Kühn, Ingolf; Ahmad, Mustaqeem; Michalski, Stefan; Auge, Harald

2017-01-01

The spread of invasive plants along elevational gradients is considered a threat to fragile mountain ecosystems, but it can also provide the opportunity to better understand some of the basic processes driving the success of invasive species. Ageratina adenophora (Asteraceae) is an invasive plant of global importance and has a broad distribution along elevational gradients in the Western Himalayas. Our study aimed at understanding the role of evolutionary processes (e.g. local adaptation and clinal differentiation) and different life history stages in shaping the distribution pattern of the invasive plant along an elevational gradient in the Western Himalaya. We carried out extensive distributional surveys, established a reciprocal transplant experiment with common gardens at three elevational levels, and measured a suite of traits related to germination, growth, reproduction and phenology. Our results showed a lack of local adaptation, and we did not find any evidence for clinal differentiation in any measured trait except a rather weak signal for plant height. We found that seed germination was the crucial life-cycle transition in determining the lower range limit while winter mortality of plants shaped the upper range limit in our study area, thus explaining the hump shaped distribution pattern. Differences in trait values between gardens for most traits indicated a high degree of phenotypic plasticity. Possible causes such as apomixis, seed dispersal among sites, and pre-adaptation might have confounded evolutionary processes to act upon. Our results suggest that the success and spread of Ageratina adenophora are dependent on different life history stages at different elevations that are controlled by abiotic conditions. PMID:29125852

Processes affecting altitudinal distribution of invasive Ageratina adenophora in western Himalaya: The role of local adaptation and the importance of different life-cycle stages.

PubMed

Datta, Arunava; Kühn, Ingolf; Ahmad, Mustaqeem; Michalski, Stefan; Auge, Harald

2017-01-01

The spread of invasive plants along elevational gradients is considered a threat to fragile mountain ecosystems, but it can also provide the opportunity to better understand some of the basic processes driving the success of invasive species. Ageratina adenophora (Asteraceae) is an invasive plant of global importance and has a broad distribution along elevational gradients in the Western Himalayas. Our study aimed at understanding the role of evolutionary processes (e.g. local adaptation and clinal differentiation) and different life history stages in shaping the distribution pattern of the invasive plant along an elevational gradient in the Western Himalaya. We carried out extensive distributional surveys, established a reciprocal transplant experiment with common gardens at three elevational levels, and measured a suite of traits related to germination, growth, reproduction and phenology. Our results showed a lack of local adaptation, and we did not find any evidence for clinal differentiation in any measured trait except a rather weak signal for plant height. We found that seed germination was the crucial life-cycle transition in determining the lower range limit while winter mortality of plants shaped the upper range limit in our study area, thus explaining the hump shaped distribution pattern. Differences in trait values between gardens for most traits indicated a high degree of phenotypic plasticity. Possible causes such as apomixis, seed dispersal among sites, and pre-adaptation might have confounded evolutionary processes to act upon. Our results suggest that the success and spread of Ageratina adenophora are dependent on different life history stages at different elevations that are controlled by abiotic conditions.

Scavenging of radioactive soluble gases from inhomogeneous atmosphere by evaporating rain droplets.

PubMed

Elperin, Tov; Fominykh, Andrew; Krasovitov, Boris

2015-05-01

We analyze effects of inhomogeneous concentration and temperature distributions in the atmosphere, rain droplet evaporation and radioactive decay of soluble gases on the rate of trace gas scavenging by rain. We employ a one-dimensional model of precipitation scavenging of radioactive soluble gaseous pollutants that is valid for small gradients and non-uniform initial altitudinal distributions of temperature and concentration in the atmosphere. We assume that conditions of equilibrium evaporation of rain droplets are fulfilled. It is demonstrated that transient altitudinal distribution of concentration under the influence of rain is determined by the linear wave equation that describes propagation of a scavenging wave front. The obtained equation is solved by the method of characteristics. Scavenging coefficients are calculated for wet removal of gaseous iodine-131 and tritiated water vapor (HTO) for the exponential initial distribution of trace gases concentration in the atmosphere and linear temperature distribution. Theoretical predictions of the dependence of the magnitude of the scavenging coefficient on rain intensity for tritiated water vapor are in good agreement with the available atmospheric measurements. Copyright © 2015 Elsevier Ltd. All rights reserved.

Elevational speciation in action? Restricted gene flow associated with adaptive divergence across an altitudinal gradient

USGS Publications Warehouse

Funk, W. C.; Murphy, M.A.; Hoke, K. L.; Muths, Erin L.; Amburgey, Staci M.; Lemmon, Emily M.; Lemmon, A. R.

2016-01-01

Evolutionary theory predicts that divergent selection pressures across elevational gradients could cause adaptive divergence and reproductive isolation in the process of ecological speciation. Although there is substantial evidence for adaptive divergence across elevation, there is less evidence that this restricts gene flow. Previous work in the boreal chorus frog (Pseudacris maculata) has demonstrated adaptive divergence in morphological, life history and physiological traits across an elevational gradient from approximately 1500–3000 m in the Colorado Front Range, USA. We tested whether this adaptive divergence is associated with restricted gene flow across elevation – as would be expected if incipient speciation were occurring – and, if so, whether behavioural isolation contributes to reproductive isolation. Our analysis of 12 microsatellite loci in 797 frogs from 53 populations revealed restricted gene flow across elevation, even after controlling for geographic distance and topography. Calls also varied significantly across elevation in dominant frequency, pulse number and pulse duration, which was partly, but not entirely, due to variation in body size and temperature across elevation. However, call variation did not result in strong behavioural isolation: in phonotaxis experiments, low-elevation females tended to prefer an average low-elevation call over a high-elevation call, and vice versa for high-elevation females, but this trend was not statistically significant. In summary, our results show that adaptive divergence across elevation restricts gene flow in P. maculata, but the mechanisms for this potential incipient speciation remain open.

A significant upward shift in plant species optimum elevation during the 20th century.

PubMed

Lenoir, J; Gégout, J C; Marquet, P A; de Ruffray, P; Brisse, H

2008-06-27

Spatial fingerprints of climate change on biotic communities are usually associated with changes in the distribution of species at their latitudinal or altitudinal extremes. By comparing the altitudinal distribution of 171 forest plant species between 1905 and 1985 and 1986 and 2005 along the entire elevation range (0 to 2600 meters above sea level) in west Europe, we show that climate warming has resulted in a significant upward shift in species optimum elevation averaging 29 meters per decade. The shift is larger for species restricted to mountain habitats and for grassy species, which are characterized by faster population turnover. Our study shows that climate change affects the spatial core of the distributional range of plant species, in addition to their distributional margins, as previously reported.

Altitudinal dynamics of glacial lakes under changing climate in the Hindu Kush, Karakoram, and Himalaya ranges

NASA Astrophysics Data System (ADS)

Ashraf, Arshad; Naz, Rozina; Iqbal, Muhammad Bilal

2017-04-01

The environmental challenges posed by global warming in the Himalayan region include early and rapid melting of snow and glaciers, creation of new lakes, and expansion of old ones posing a high risk of glacial lakes outburst flood (GLOF) hazard for downstream communities. According to various elevation ranges, 3044 lakes were analyzed basinwide in the Hindu Kush-Karakoram-Himalaya (HKH) ranges of Pakistan using multisensor remote sensing data of the 2001-2013 period. An overall increase in glacial lakes was observed at various altitudinal ranges between 2500 and 5500, m out of which noticeable change by number was within the 4000-4500 m range. The analysis carried out by glacial-fed lakes and nonglacial-fed lakes in different river basins indicated variable patterns depending on the geographic location in the HKH region. The correlation analysis of parameters like lake area, expansion rate, and elevation was performed with 617 glacial lakes distributed in various river basins of the three HKH ranges. Lake area (2013) and elevation showed a negative relationship for all basins except Hunza, Shigar, and Shyok. The correlation between the expansion rate of lakes and elevation was on the positive side for Swat, Gilgit, Shigar, and Shingo basins-a situation that may be attributed to the variable altitudinal pattern of temperature and precipitation. In order to explore such diverse patterns of lake behavior and relationship with influential factors in the HKH, detailed studies based on using high resolution image data coupled with in situ information are a prerequisite. Although an increase in lake area observed below 3500 m would be favorable for water resource management, but could be alarming in context of glacial flood hazards that need to be monitored critically on a long-term basis.

The Biogeographic Pattern of Microbial Functional Genes along an Altitudinal Gradient of the Tibetan Pasture

PubMed Central

Qi, Qi; Zhao, Mengxin; Wang, Shiping; Ma, Xingyu; Wang, Yuxuan; Gao, Ying; Lin, Qiaoyan; Li, Xiangzhen; Gu, Baohua; Li, Guoxue; Zhou, Jizhong; Yang, Yunfeng

2017-01-01

As the highest place of the world, the Tibetan plateau is a fragile ecosystem. Given the importance of microbial communities in driving soil nutrient cycling, it is of interest to document the microbial biogeographic pattern here. We adopted a microarray-based tool named GeoChip 4.0 to investigate grassland microbial functional genes along an elevation gradient from 3200 to 3800 m above sea level open to free grazing by local herdsmen and wild animals. Interestingly, microbial functional diversities increase with elevation, so does the relative abundances of genes associated with carbon degradation, nitrogen cycling, methane production, cold shock and oxygen limitation. The range of Shannon diversities (10.27–10.58) showed considerably smaller variation than what was previously observed at ungrazed sites nearby (9.95–10.65), suggesting the important role of livestock grazing on microbial diversities. Closer examination showed that the dissimilarity of microbial community at our study sites increased with elevations, revealing an elevation-decay relationship of microbial functional genes. Both microbial functional diversity and the number of unique genes increased with elevations. Furthermore, we detected a tight linkage of greenhouse gas (CO2) and relative abundances of carbon cycling genes. Our biogeographic study provides insights on microbial functional diversity and soil biogeochemical cycling in Tibetan pastures. PMID:28659870

Parallel altitudinal clines reveal trends in adaptive evolution of genome size in Zea mays

PubMed Central

Berg, Jeremy J.; Birchler, James A.; Grote, Mark N.; Lorant, Anne; Quezada, Juvenal

2018-01-01

While the vast majority of genome size variation in plants is due to differences in repetitive sequence, we know little about how selection acts on repeat content in natural populations. Here we investigate parallel changes in intraspecific genome size and repeat content of domesticated maize (Zea mays) landraces and their wild relative teosinte across altitudinal gradients in Mesoamerica and South America. We combine genotyping, low coverage whole-genome sequence data, and flow cytometry to test for evidence of selection on genome size and individual repeat abundance. We find that population structure alone cannot explain the observed variation, implying that clinal patterns of genome size are maintained by natural selection. Our modeling additionally provides evidence of selection on individual heterochromatic knob repeats, likely due to their large individual contribution to genome size. To better understand the phenotypes driving selection on genome size, we conducted a growth chamber experiment using a population of highland teosinte exhibiting extensive variation in genome size. We find weak support for a positive correlation between genome size and cell size, but stronger support for a negative correlation between genome size and the rate of cell production. Reanalyzing published data of cell counts in maize shoot apical meristems, we then identify a negative correlation between cell production rate and flowering time. Together, our data suggest a model in which variation in genome size is driven by natural selection on flowering time across altitudinal clines, connecting intraspecific variation in repetitive sequence to important differences in adaptive phenotypes. PMID:29746459

To what extent is altitudinal variation of functional traits driven by genetic adaptation in European oak and beech?

PubMed

Bresson, Caroline C; Vitasse, Yann; Kremer, Antoine; Delzon, Sylvain

2011-11-01

The phenotypic responses of functional traits in natural populations are driven by genetic diversity and phenotypic plasticity. These two mechanisms enable trees to cope with rapid climate change. We studied two European temperate tree species (sessile oak and European beech), focusing on (i) in situ variations of leaf functional traits (morphological and physiological) along two altitudinal gradients and (ii) the extent to which these variations were under environmental and/or genetic control using a common garden experiment. For all traits, altitudinal trends tended to be highly consistent between species and transects. For both species, leaf mass per area displayed a positive linear correlation with altitude, whereas leaf size was negatively correlated with altitude. We also observed a significant increase in leaf physiological performance with increasing altitude: populations at high altitudes had higher maximum rates of assimilation, stomatal conductance and leaf nitrogen content than those at low altitudes. In the common garden experiment, genetic differentiation between populations accounted for 0-28% of total phenotypic variation. However, only two traits (leaf mass per area and nitrogen content) exhibited a significant cline. The combination of in situ and common garden experiments used here made it possible to demonstrate, for both species, a weaker effect of genetic variation than of variations in natural conditions, suggesting a strong effect of the environment on leaf functional traits. Finally, we demonstrated that intrapopulation variability was systematically higher than interpopulation variability, whatever the functional trait considered, indicating a high potential capacity to adapt to climate change.

Shrub type dominates the vertical distribution of leaf C : N : P stoichiometry across an extensive altitudinal gradient

NASA Astrophysics Data System (ADS)

Zhao, Wenqiang; Reich, Peter B.; Yu, Qiannan; Zhao, Ning; Yin, Chunying; Zhao, Chunzhang; Li, Dandan; Hu, Jun; Li, Ting; Yin, Huajun; Liu, Qing

2018-04-01

Understanding leaf stoichiometric patterns is crucial for improving predictions of plant responses to environmental changes. Leaf stoichiometry of terrestrial ecosystems has been widely investigated along latitudinal and longitudinal gradients. However, very little is known about the vertical distribution of leaf C : N : P and the relative effects of environmental parameters, especially for shrubs. Here, we analyzed the shrub leaf C, N and P patterns in 125 mountainous sites over an extensive altitudinal gradient (523-4685 m) on the Tibetan Plateau. Results showed that the shrub leaf C and C : N were 7.3-47.5 % higher than those of other regional and global flora, whereas the leaf N and N : P were 10.2-75.8 % lower. Leaf C increased with rising altitude and decreasing temperature, supporting the physiological acclimation mechanism that high leaf C (e.g., alpine or evergreen shrub) could balance the cell osmotic pressure and resist freezing. The largest leaf N and high leaf P occurred in valley region (altitude 1500 m), likely due to the large nutrient leaching from higher elevations, faster litter decomposition and nutrient resorption ability of deciduous broadleaf shrub. Leaf N : P ratio further indicated increasing N limitation at higher altitudes. Interestingly, drought severity was the only climatic factor positively correlated with leaf N and P, which was more appropriate for evaluating the impact of water status than precipitation. Among the shrub ecosystem and functional types (alpine, subalpine, montane, valley, evergreen, deciduous, broadleaf, and conifer), their leaf element contents and responses to environments were remarkably different. Shrub type was the largest contributor to the total variations in leaf stoichiometry, while climate indirectly affected the leaf C : N : P via its interactive effects on shrub type or soil. Collectively, the large heterogeneity in shrub type was the most important factor explaining the overall leaf C : N : P variations, despite the broad climate gradient on the plateau. Temperature and drought induced shifts in shrub type distribution will influence the nutrient accumulation in mountainous shrubs.

Modeling the potential effects of climate change on high elevation vegetation in the Olympic Mountains

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zolbrod, A.N.; Peterson, D.L.

1995-06-01

Subalpine and alpine vegetation may be particularly sensitive to climatic change, such as expected temperature increases and altered precipitation patterns with global warming. The gap replacement model ZELIG was modified and used to examine transient and steady-state changes in altitudinal treeline, tree species distribution, and forest structure and composition along elevation gradients in the Olympic Mountains, Washington, under a range of temperature and precipitation changes. Changes in vegetation pattern were examined for north vs. south aspects, and wet (southwest) vs. dry (northeast) regions of the mountains. The seedling establishment subroutine in ZELIG was improved to specifically model the complexities ofmore » tree invasion in subalpine meadows and include empirical data. A function allowing for stand replacement fire was also added in order to examine the role of altered disturbance regimes on vegetation change. Results indicate that distribution of tree species will change under various climate change scenarios, but future elevation of treeline depends greatly on precipitation levels, disturbance frequency, and aspect.« less

Species-environment interactions changed by introduced herbivores in an oceanic high-mountain ecosystem.

PubMed

Seguí, Jaume; López-Darias, Marta; Pérez, Antonio J; Nogales, Manuel; Traveset, Anna

2017-01-05

Summit areas of oceanic islands constitute some of the most isolated ecosystems on earth, highly vulnerable to climate change and introduced species. Within the unique high-elevation communities of Tenerife (Canary Islands), reproductive success and thus long-term survival of species may depend on environmental suitability as well as threat by introduced herbivores. By experimentally modifying the endemic and vulnerable species Viola cheiranthifolia along its entire altitudinal occurrence range, we studied plant performance, autofertility, pollen limitation and visitation rate and the interactive effect of grazing by non-native rabbits on them. We assessed the grazing effects by recording (1) the proportion of consumed plants and flowers along the gradient, (2) comparing fitness traits of herbivore-excluded plants along the gradient, and (3) comparing fitness traits, autofertility and pollen limitation between plants excluded from herbivores with unexcluded plants at the same locality. Our results showed that V. cheiranthifolia performance is mainly affected by inter-annual and microhabitat variability along the gradient, especially in the lowest edge. Despite the increasingly adverse environmental conditions, the plant showed no pollen limitation with elevation, which is attributed to the increase in autofertility levels (≥ 50% of reproductive output) and decrease in competition for pollinators at higher elevations. Plant fitness is, however, extremely reduced owing to the presence of non-native rabbits in the area (consuming more than 75% of the individuals in some localities), which in turn change plant trait-environment interactions along the gradient. Taken together, these findings indicate that the elevational variation found on plant performance results from the combined action of non-native rabbits with the microhabitat variability, exerting intricate ecological influences that threaten the survival of this violet species. Published by Oxford University Press on behalf of the Annals of Botany Company.

Cultivable bacterial diversity along the altitudinal zonation and vegetation range of tropical Eastern Himalaya.

PubMed

Lyngwi, Nathaniel A; Koijam, Khedarani; Sharma, D; Joshi, S R

2013-03-01

The Northeastern part of India sprawls over an area of 262 379km2 in the Eastern Himalayan range. This constitutes a biodiversity hotspot with high levels of biodiversity and endemism; unfortunately, is also a poorly known area, especially on its microbial diversity. In this study, we assessed cultivable soil bacterial diversity and distribution from lowlands to highlands (34 to 3 990m.a.s.l.). Soil physico-chemical parameters and forest types across the different altitudes were characterized and correlated with bacterial distribution and diversity. Microbes from the soil samples were grown in Nutrient, Muller Hinton and Luria-Bertani agar plates and were initially characterized using biochemical methods. Parameters like dehydrogenase and urease activities, temperature, moisture content, pH, carbon content, bulk density of the sampled soil were measured for each site. Representative isolates were also subjected to 16S rDNA sequence analysis. A total of 155 cultivable bacterial isolates were characterized which were analyzed for richness, evenness and diversity indices. The tropical and sub-tropical forests supported higher bacterial diversity compared to temperate pine, temperate conifer, and sub-alpine rhododendron forests. The 16S rRNA phylogenetic analysis revealed that Firmicutes was the most common group followed by Proteobacreria and Bacteroidetes. Species belonging to the genera Bacillus and Pseudomonas were the most abundant. Bacterial CFU showed positive but insignificant correlation with soil parameters like pH (r=0.208), soil temperature (r=0.303), ambient temperature (r=0.443), soil carbon content (r=0.525), soil bulk density (r=0.268), soil urease (r=0.549) and soil dehydrogenase (r=0.492). Altitude (r=-0.561) and soil moisture content (r=-0.051) showed negative correlation. Altitudinal gradient along with the vegetation and soil physico-chemical parameters were found to influence bacterial diversity and distribution. This study points out that this is a biome with a vast reservoir of bacteria which decrease with increasing altitudes, and highlights the microbiological importance of the poorly studied Eastern Himalayan range, justifying efforts to explore the prevalence of novel species in the biome.

High Altitude Bird Migration at Temperate Latitudes: A Synoptic Perspective on Wind Assistance

PubMed Central

Dokter, Adriaan M.; Shamoun-Baranes, Judy; Kemp, Michael U.; Tijm, Sander; Holleman, Iwan

2013-01-01

At temperate latitudes the synoptic patterns of bird migration are strongly structured by the presence of cyclones and anticyclones, both in the horizontal and altitudinal dimensions. In certain synoptic conditions, birds may efficiently cross regions with opposing surface wind by choosing a higher flight altitude with more favourable wind. We observed migratory passerines at mid-latitudes that selected high altitude wind optima on particular nights, leading to the formation of structured migration layers at varying altitude up to 3 km. Using long-term vertical profiling of bird migration by C-band Doppler radar in the Netherlands, we find that such migration layers occur nearly exclusively during spring migration in the presence of a high-pressure system. A conceptual analytic framework providing insight into the synoptic patterns of wind assistance for migrants that includes the altitudinal dimension has so far been lacking. We present a simple model for a baroclinic atmosphere that relates vertical profiles of wind assistance to the pressure and temperature patterns occurring at temperate latitudes. We show how the magnitude and direction of the large scale horizontal temperature gradient affects the relative gain in wind assistance that migrants obtain through ascending. Temperature gradients typical for northerly high-pressure systems in spring are shown to cause high altitude wind optima in the easterly sectors of anticyclones, thereby explaining the frequent observations of high altitude migration in these synoptic conditions. Given the recurring synoptic arrangements of pressure systems across temperate continents, the opportunities for exploiting high altitude wind will differ between flyways, for example between easterly and westerly oceanic coasts. PMID:23300969

High altitude bird migration at temperate latitudes: a synoptic perspective on wind assistance.

PubMed

Dokter, Adriaan M; Shamoun-Baranes, Judy; Kemp, Michael U; Tijm, Sander; Holleman, Iwan

2013-01-01

At temperate latitudes the synoptic patterns of bird migration are strongly structured by the presence of cyclones and anticyclones, both in the horizontal and altitudinal dimensions. In certain synoptic conditions, birds may efficiently cross regions with opposing surface wind by choosing a higher flight altitude with more favourable wind. We observed migratory passerines at mid-latitudes that selected high altitude wind optima on particular nights, leading to the formation of structured migration layers at varying altitude up to 3 km. Using long-term vertical profiling of bird migration by C-band Doppler radar in the Netherlands, we find that such migration layers occur nearly exclusively during spring migration in the presence of a high-pressure system. A conceptual analytic framework providing insight into the synoptic patterns of wind assistance for migrants that includes the altitudinal dimension has so far been lacking. We present a simple model for a baroclinic atmosphere that relates vertical profiles of wind assistance to the pressure and temperature patterns occurring at temperate latitudes. We show how the magnitude and direction of the large scale horizontal temperature gradient affects the relative gain in wind assistance that migrants obtain through ascending. Temperature gradients typical for northerly high-pressure systems in spring are shown to cause high altitude wind optima in the easterly sectors of anticyclones, thereby explaining the frequent observations of high altitude migration in these synoptic conditions. Given the recurring synoptic arrangements of pressure systems across temperate continents, the opportunities for exploiting high altitude wind will differ between flyways, for example between easterly and westerly oceanic coasts.

Direct and indirect effects of climate on demography and early growth of Pinus sylvestris at the rear edge: changing roles of biotic and abiotic factors.

PubMed

Benavides, Raquel; Rabasa, Sonia G; Granda, Elena; Escudero, Adrián; Hódar, José A; Martínez-Vilalta, Jordi; Rincón, Ana M; Zamora, Regino; Valladares, Fernando

2013-01-01

Global change triggers shifts in forest composition, with warming and aridification being particularly threatening for the populations located at the rear edge of the species distributions. This is the case of Scots pine (Pinus sylvestris) in the Mediterranean Basin where uncertainties in relation to its dynamics under these changing scenarios are still high. We analysed the relative effect of climate on the recruitment patterns of Scots pine and its interactions with local biotic and abiotic variables at different spatial scales. Number of seedlings and saplings was surveyed, and their annual shoot growth measured in 96 plots located across altitudinal gradients in three different regions in the Iberian Peninsula. We found a significant influence of climate on demography and performance of recruits, with a non-linear effect of temperature on the presence of juveniles, and a positive effect of precipitation on their survival. Abundance of juveniles of P. sylvestris that underwent their first summer drought was skewed towards higher altitudes than the altitudinal mean range of the conspecific adults and the optimum elevation for seedlings' emergence. At local level, light availability did not influence juveniles' density, but it enhanced their growth. Biotic interactions were found between juveniles and the herb cover (competition) and between the number of newly emerged seedlings and shrubs (facilitation). Results also highlighted the indirect effect that climate exerts over the local factors, modulating the interactions with the pre-existing vegetation that were more evident at more stressful sites. This multiscale approach improves our understanding of the dynamics of these marginal populations and some management criteria can be inferred to boost their conservation under the current global warming.

Toughness of the Virunga mountain gorilla (Gorilla beringei beringei) diet across an altitudinal gradient.

PubMed

Glowacka, Halszka; McFarlin, Shannon C; Vogel, Erin R; Stoinski, Tara S; Ndagijimana, Felix; Tuyisingize, Deo; Mudakikwa, Antoine; Schwartz, Gary T

2017-08-01

The robust masticatory system of mountain gorillas is thought to have evolved for the comminution of tough vegetation, yet, compared to other primates, the toughness of the mountain gorilla diet is unremarkable. This may be a result of low plant toughness in the mountain gorilla environment or of mountain gorillas feeding selectively on low-toughness foods. The goal of this paper is to determine how the toughness of the mountain gorilla diet varies across their habitat, which spans a large altitudinal range, and whether there is a relationship between toughness and food selection by mountain gorillas. We collected data on the following variables to determine whether, and if so how, they change with altitude: leaf toughness of two plant species consumed by mountain gorillas, at every 100 m increase in altitude (2,600-3,700 m); toughness of consumed foods comprising over 85% of the gorilla diet across five vegetation zones; and toughness of unconsumed/infrequently consumed plant parts of those foods. Although leaf toughness increased with altitude, the toughness of the gorilla diet remained similar. There was a negative relationship between toughness and consumption frequency, and toughness was a better predictor of consumption frequency than plant frequency, biomass, and density. Consumed plant parts were less tough than unconsumed/infrequently consumed parts and toughness of the latter increased with altitude. Although it is unclear whether gorillas select food based on toughness or use toughness as a sensory cue to impart other plant properties (e.g., macronutrients, chemicals), our results that gorillas maintain a consistent low-toughness dietary profile across altitude, despite toughness increasing with altitude, suggest that the robust gorilla masticatory apparatus evolved for repetitive mastication of foods that are not high in toughness. © 2017 Wiley Periodicals, Inc.

Ethnobotanical Study of Herbaceous Flora along an Altitudinal Gradient in Bharmour Forest Division, District Chamba of Himachal Pradesh, India.

PubMed

Thakur, Kehar S; Kumar, Munesh; Bawa, Rajan; Bussmann, Rainer W

2014-01-01

The present ethnobotanical study was carried out in Holi (Deol, Kut, Dal, and Lahaud Dhar) forest range and in Bharmor (Seri, Bharmour, Malkauta, Bharmani, Harsar, Dhancho, Sundrasi, Gorikund, and Manimahesh) forest range to obtain information on the plants used by the local inhabitants for several purposes. A total of 54 plants were recorded in this study. The plants are employed to treat simple diseases (cough, cold, fever, and burns) and some serious diseases (typhoid, jaundice, and kidney disease). Some of the plants are also used as incense for religious ceremonies and several other daily needs. But due to absence of scientific monitoring of plants, their cultivation, harvesting, and management techniques as well as sustainable use and lack of awareness of social factors, the availability of valuable plant resources is decreasing at an alarming rate. In addition, the indigenous knowledge regarding the use of lesser-known plants of this region is also rapidly declining. Therefore, the documentation of plant resources is a necessary step towards the goal of raising awareness in local communities about the importance of these plants and their further conservation.

Ethnobotanical Study of Herbaceous Flora along an Altitudinal Gradient in Bharmour Forest Division, District Chamba of Himachal Pradesh, India

PubMed Central

Thakur, Kehar S.; Kumar, Munesh; Bawa, Rajan; Bussmann, Rainer W.

2014-01-01

The present ethnobotanical study was carried out in Holi (Deol, Kut, Dal, and Lahaud Dhar) forest range and in Bharmor (Seri, Bharmour, Malkauta, Bharmani, Harsar, Dhancho, Sundrasi, Gorikund, and Manimahesh) forest range to obtain information on the plants used by the local inhabitants for several purposes. A total of 54 plants were recorded in this study. The plants are employed to treat simple diseases (cough, cold, fever, and burns) and some serious diseases (typhoid, jaundice, and kidney disease). Some of the plants are also used as incense for religious ceremonies and several other daily needs. But due to absence of scientific monitoring of plants, their cultivation, harvesting, and management techniques as well as sustainable use and lack of awareness of social factors, the availability of valuable plant resources is decreasing at an alarming rate. In addition, the indigenous knowledge regarding the use of lesser-known plants of this region is also rapidly declining. Therefore, the documentation of plant resources is a necessary step towards the goal of raising awareness in local communities about the importance of these plants and their further conservation. PMID:24876884

Fog Chemistry at Different Altitudes in the Swiss Alps

NASA Astrophysics Data System (ADS)

Michna, P.; Eugster, W.; Wanner, H.

2010-07-01

During two extended summer seasons in 2006 and 2007, we installed two battery driven versions of the Caltech active strand cloud water collector (MiniCASCC) at the Niesen mountain in the northern Swiss Alps. Along, we measured air temperature, relative humidity, wind, and visibility. During these two field operation phases we gained weekly samples of fogwater, where we analysed the major anions and cations, and the stable water isotopes δD and δ18O. The fog collectors were installed at an altitude of 2300 and 1600 m asl to resolve altitudinal differences in fog chemistry. We found a large variability between the events, but no clear altitudinal gradient. At both sites, the most important ions were nitrate, ammonium, and sulphate. Higher concentrations occured preferably in late spring (start of sampling period) and in autumn (end of sampling). Compared to previous studies at lower elevations in the Swiss Plateau during wintertime, our measurements showed considerable lower ion loads in the fogwater. The combination of these results suggest that lowest ion loads are found in convective clouds with a short lifetime and that the highest ion loads occur during radiation fog events at lower elevations.

Soilscapes in the dynamic tropical environments: The case of Sierra Madre del Sur

NASA Astrophysics Data System (ADS)

Krasilnikov, P. V.; García-Calderón, N. E.; Ibáñez-Huerta, A.; Bazán-Mateos, M.; Hernández-Santana, J. R.

2011-12-01

The paper gives an analysis of the pattern of soil cover of the Sierra Madre del Sur, one of the most complex physiographic regions of Mexico. It presents the results of the study of four latitudinal traverses across the region. We show that the distribution of soils in the Sierra Madre del Sur is associated with major climatic gradients, namely by vertical bioclimatic zonality in the mountains and by the effect of mountain shadow. Altitudinal distribution of soil-bioclimatic belts is complex due to non-uniform gradients of temperature and rainfall, and varies with the configuration of the mountain range. The distribution of soils is associated with the erosion and accumulation rates both on mountain slopes and in river valleys. The abundance of poorly developed soils in (semi)arid areas was ascribed to high erosion rate rather than to low pedogenetic potential. The formation of soil mosaic at a larger scale might be ascribed to the complex net of gully erosion and to the system of seismically triggered landslides of various ages. In the valleys, the distribution of soils depends upon the dynamics of sedimentation and erosion, which eventually exposes paleosols. Red-colored clayey sediments are remains of ancient weathering and pedogenesis. Their distribution is associated mainly with the intensity of recent slope processes. The soil cover pattern of the Sierra Madre del Sur cannot be explained by simplified schemes of bioclimatic zonality. The soil ranges can be explained by the distribution of climates, lithology, complex geological history of the region, and recent geomorphological processes.

Population Fluctuation of Ceratitis capitata (Diptera: Tephritidae) as a Function of Altitude in Eastern Guatemala.

PubMed

Flores, S; Montoya, P; Ruiz-Montoya, L; Villaseñor, A; Valle, A; Enkerlin, W; Liedo, P

2016-08-01

Population fluctuations of Ceratitis capitata (Wiedemann) were evaluated over a period of 12 mo in four altitudinal strata (400-750, 750-1,100, 1,100-1,450, and 1,450-1,800 meters above sea level, masl) in Eastern Guatemala. Within each altitudinal range, sampling plots were established in coffee plantations and adjacent areas, in which Jackson traps were set and baited with Trimedlure. Coffee berries and other host fruits were collected. Population density was lowest at the 400-750 masl stratum and highest at 1,450-1,800 masl. At every altitudinal range, the fluctuations of the pest were associated mainly with the availability of ripe coffee berries as a primary host. From 750-1,450 masl, the pest was also associated with the availability of sweet orange and mandarins in commercial and backyard orchards. The highest densities of the pest were recorded in the dry season. Citrus were the main alternate host where ripe coffee berries were not available. This knowledge on population dynamics of C. capitata will contribute to develop more effective area-wide pest management strategies including the use of sterile insects, natural enemies, and bait sprays. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Integrative overview of the herpetofauna from Serra da Mocidade, a granitic mountain range in northern Brazil.

PubMed

Moraes, Leandro J C L; de Almeida, Alexandre P; de Fraga, Rafael; Rojas, Rommel R; Pirani, Renata M; Silva, Ariane A A; de Carvalho, Vinícius T; Gordo, Marcelo; Werneck, Fernanda P

2017-01-01

The Brazilian mountain ranges from the Guiana Shield highlands are largely unexplored, with an understudied herpetofauna. Here the amphibian and reptile species diversity of the remote Serra da Mocidade mountain range, located in extreme northern Brazil, is reported upon, and biogeographical affinities and taxonomic highlights are discussed. A 22-days expedition to this mountain range was undertaken during which specimens were sampled at four distinct altitudinal levels (600, 960, 1,060 and 1,365 m above sea level) using six complementary methods. Specimens were identified through an integrated approach that considered morphological, bioacoustical, and molecular analyses. Fifty-one species (23 amphibians and 28 reptiles) were found, a comparable richness to other mountain ranges in the region. The recorded assemblage showed a mixed compositional influence from assemblages typical of other mountain ranges and lowland forest habitats in the region. Most of the taxa occupying the Serra da Mocidade mountain range are typical of the Guiana Shield or widely distributed in the Amazon. Extensions of known distribution ranges and candidate undescribed taxa are also recorded. This is the first herpetofaunal expedition that accessed the higher altitudinal levels of this mountain range, contributing to the basic knowledge of these groups in remote areas.

Integrative overview of the herpetofauna from Serra da Mocidade, a granitic mountain range in northern Brazil

PubMed Central

Moraes, Leandro J.C.L.; de Almeida, Alexandre P.; de Fraga, Rafael; Rojas, Rommel R.; Pirani, Renata M.; Silva, Ariane A.A.; de Carvalho, Vinícius T.; Gordo, Marcelo; Werneck, Fernanda P.

2017-01-01

Abstract The Brazilian mountain ranges from the Guiana Shield highlands are largely unexplored, with an understudied herpetofauna. Here the amphibian and reptile species diversity of the remote Serra da Mocidade mountain range, located in extreme northern Brazil, is reported upon, and biogeographical affinities and taxonomic highlights are discussed. A 22-days expedition to this mountain range was undertaken during which specimens were sampled at four distinct altitudinal levels (600, 960, 1,060 and 1,365 m above sea level) using six complementary methods. Specimens were identified through an integrated approach that considered morphological, bioacoustical, and molecular analyses. Fifty-one species (23 amphibians and 28 reptiles) were found, a comparable richness to other mountain ranges in the region. The recorded assemblage showed a mixed compositional influence from assemblages typical of other mountain ranges and lowland forest habitats in the region. Most of the taxa occupying the Serra da Mocidade mountain range are typical of the Guiana Shield or widely distributed in the Amazon. Extensions of known distribution ranges and candidate undescribed taxa are also recorded. This is the first herpetofaunal expedition that accessed the higher altitudinal levels of this mountain range, contributing to the basic knowledge of these groups in remote areas. PMID:29302235

Wood-inhabiting fungi in southern Italy forest stands: morphogroups, vegetation types and decay classes.

PubMed

Granito, Vito Mario; Lunghini, Dario; Maggi, Oriana; Persiani, Anna Maria

2015-01-01

The authors conducted an ecological study of forests subjected to varying management. The aim of the study was to extend and integrate, within a multivariate context, knowledge of how saproxylic fungal communities behave along altitudinal/vegetational gradients in response to the varying features and quality of coarse woody debris (CWD). The intra-annual seasonal monitoring of saproxylic fungi, based on sporocarp inventories, was used to investigate saproxylic fungi in relation to vegetation types and management categories. We analyzed fungal species occurrence, recorded according to the presence/absence and frequency of sporocarps, on the basis of the harvest season, of coarse woody debris decay classes as well as other environmental and ecological variables. Two-way cluster analysis, DCA and Spearman's rank correlations, for indirect gradient analysis, were performed to identify any patterns of seasonality and decay. Most of the species were found on CWD in an intermediate decay stage. The first DCA axis revealed the vegetational/microclimate gradient as the main driver of fungal community composition, while the second axis corresponded to a strong gradient of CWD decay classes. © 2015 by The Mycological Society of America.

The Biogeographic Pattern of Microbial Functional Genes along an Altitudinal Gradient of the Tibetan Pasture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qi, Qi; Zhao, Mengxin; Wang, Shiping

As the highest place of the world, the Tibetan plateau is a fragile ecosystem. Given the importance of microbial communities in driving soil nutrient cycling, it is of interest to document the microbial biogeographic pattern here. We adopted a microarray-based tool named GeoChip 4.0 to investigate grassland microbial functional genes along an elevation gradient from 3200 to 3800 m above sea level open to free grazing by local herdsmen and wild animals. Interestingly, microbial functional diversities increase with elevation, so does the relative abundances of genes associated with carbon degradation, nitrogen cycling, methane production, cold shock and oxygen limitation. Themore » range of Shannon diversities (10.27–10.58) showed considerably smaller variation than what was previously observed at ungrazed sites nearby (9.95–10.65), suggesting the important role of livestock grazing on microbial diversities. Closer examination showed that the dissimilarity of microbial community at our study sites increased with elevations, revealing an elevation-decay relationship of microbial functional genes. Both microbial functional diversity and the number of unique genes increased with elevations. Furthermore, we detected a tight linkage of greenhouse gas (CO2) and relative abundances of carbon cycling genes. Our biogeographic study provides insights on microbial functional diversity and soil biogeochemical cycling in Tibetan pastures.« less

Intraspecific variation in the energetics of the Cabrera vole.

PubMed

Castellanos-Frías, Elena; García-Perea, Rosa; Gisbert, Julio; Bozinovic, Francisco; Virgós, Emilio

2015-12-01

Basal metabolic rate (BMR) is an intensively topic studied in ecophysiology for the purpose of understanding energy budgets of the species, variations of energy expenditure during their diary activities and physiological acclimatization to the environment. Establishing how the metabolism is assembled to the environment can provide valuable data to improve conservation strategies of endangered species. In this sense, metabolic differences associated to habitats have been widely reported in the interspecific level, however little is known about the intraspecific view of BMR under an environmental gradient. In this study, we researched the effect of the habitat on metabolic rate of an Iberian endemic species: Iberomys cabrerae. Animals were captured in different subpopulations of its altitudinal range and their MR was studied over a thermal gradient. MR was analyzed through a Linear Mixed Model (LMM) in which, in addition to thermal effects, the bioclimatic zone and sex also influenced the metabolism of the species. The beginning of thermoneutrality zone was set on 26.5°C and RMR was 2.3ml O2g(-1)h(-1), intermediate between both bioclimatic zones. Supramediterranean subpopulations started the Tlc earlier (24.9°C) and had higher RMR than the mesomediterranean ones (26.9°C). The thermal environment together with primary productivity conditions could explain this difference in the metabolic behaviour of the Cabrera voles. Copyright © 2015 Elsevier Inc. All rights reserved.

Structure of dung beetle communities in an altitudinal gradient of neotropical dry forest.

PubMed

Domínguez, D; Marín-Armijos, D; Ruiz, C

2015-02-01

To understand the effects of global warming in tropical insect communities, it is necessary to comprehend how such communities respond to different abiotic factors that covariate with altitude. In this study, we partially answer this question applied to dung beetle communities distributed along an altitudinal gradient. The sampling was conducted in seven stations 100 m apart each in altitude in a dry mountain scrub in southern Ecuador. A total of 7422 individuals belonging to six species were captured. Canthon balteatus Boheman was the most abundant with 6502 individuals, and Onoreidium ohausi (Arrow) was the least abundant with 20 individuals. We found significant changes in the structure of the dung beetle communities with altitude. Two abiotic factors showed a relationship with the abundance pattern for all species (altitude, Z = 0.011, p < 0.01, and temperature, Z = 0.859, p < 0.01). Canthon balteatus Boheman showed a positive relationship with altitude (Z = 1.422, p < 0.001) and temperature (Z = 1.121, p < 0.001), Dichotomius problematicus (Lüederwaldt) a positive relationship with precipitation (Z = 0.113, p < 0.001), and Malagoniella cupreicollis (Waterhouse) a positive relationship with temperature (Z = 0.668, p < 0.001) and negative with precipitation (Z = -0.189, p < 0.001). Phanaeus achilles Boheman, Onthophagus sp., and O. ohausi (Arrow) did not show any relationship with the studied variables, nor was the richness correlated with the studied variables. These results suggest that the effects of global warming over dung beetle communities will be difficult to predict because of species-specific responses to global warming.

Soil pH determines fungal diversity along an elevation gradient in Southwestern China.

PubMed

Liu, Dan; Liu, Guohua; Chen, Li; Wang, Juntao; Zhang, Limei

2018-01-03

Fungi play important roles in ecosystem processes, and the elevational pattern of fungal diversity is still unclear. Here, we examined the diversity of fungi along a 1,000 m elevation gradient on Mount Nadu, Southwestern China. We used MiSeq sequencing to obtain fungal sequences that were clustered into operational taxonomic units (OTUs) and to measure the fungal composition and diversity. Though the species richness and phylogenetic diversity of the fungal community did not exhibit significant trends with increasing altitude, they were significantly lower at mid-altitudinal sites than at the base. The Bray-Curtis distance clustering also showed that the fungal communities varied significantly with altitude. A distance-based linear model multivariate analysis (DistLM) identified that soil pH dominated the explanatory power of the species richness (23.72%), phylogenetic diversity (24.25%) and beta diversity (28.10%) of the fungal community. Moreover, the species richness and phylogenetic diversity of the fungal community increased linearly with increasing soil pH (P<0.05). Our study provides evidence that pH is an important predictor of soil fungal diversity along elevation gradients in Southwestern China.

Variations in chemical sexual signals of Psammodromus algirus lizards along an elevation gradient may reflect altitudinal variation in microclimatic conditions

NASA Astrophysics Data System (ADS)

Martín, José; Javier Zamora-Camacho, Francisco; Reguera, Senda; López, Pilar; Moreno-Rueda, Gregorio

2017-04-01

Chemical signals used in intraspecific communication are expected to evolve or to show phenotipic plasticity to maximize efficacy in the climatic conditions of a given environment. Elevational environmental gradients in mountains provide a good opportunity to test this hypothesis by examining variation in characteristics of signals in species found across different elevations with different climatic conditions. We analyzed by gas chromatography-mass spectrometry (GC-MS) the lipophilic fraction of the femoral gland secretions of male lizards Psammodromus algirus (Fam. Lacertidae) from six localities located along a 2200 m elevational gradient at Sierra Nevada Mountains (SE Spain). There was elevational clinal variation in climatic variables, number of femoral pores and in the relative proportions of some classes of compounds (i.e., ethyl esters of fatty acids, waxy esters, and aldehydes) but not others. We discuss how this variation would result in different physicochemical properties of the entire femoral secretion, which might help optimize the efficacy of chemical signals under the particular microclimatic conditions at each elevation.

Variations in chemical sexual signals of Psammodromus algirus lizards along an elevation gradient may reflect altitudinal variation in microclimatic conditions.

PubMed

Martín, José; Javier Zamora-Camacho, Francisco; Reguera, Senda; López, Pilar; Moreno-Rueda, Gregorio

2017-04-01

Chemical signals used in intraspecific communication are expected to evolve or to show phenotipic plasticity to maximize efficacy in the climatic conditions of a given environment. Elevational environmental gradients in mountains provide a good opportunity to test this hypothesis by examining variation in characteristics of signals in species found across different elevations with different climatic conditions. We analyzed by gas chromatography-mass spectrometry (GC-MS) the lipophilic fraction of the femoral gland secretions of male lizards Psammodromus algirus (Fam. Lacertidae) from six localities located along a 2200 m elevational gradient at Sierra Nevada Mountains (SE Spain). There was elevational clinal variation in climatic variables, number of femoral pores and in the relative proportions of some classes of compounds (i.e., ethyl esters of fatty acids, waxy esters, and aldehydes) but not others. We discuss how this variation would result in different physicochemical properties of the entire femoral secretion, which might help optimize the efficacy of chemical signals under the particular microclimatic conditions at each elevation.

Contrasting Effects of Extreme Drought and Snowmelt Patterns on Mountain Plants along an Elevation Gradient.

PubMed

Rosbakh, Sergey; Leingärtner, Annette; Hoiss, Bernhard; Krauss, Jochen; Steffan-Dewenter, Ingolf; Poschlod, Peter

2017-01-01

Despite the evidence that increased frequency and magnitude of extreme climate events (ECE) considerably affect plant performance, there is still a lack of knowledge about how these events affect mountain plant biodiversity and mountain ecosystem functioning. Here, we assessed the short-term (one vegetation period) effects of simulated ECEs [extreme drought (DR), advanced and delayed snowmelt (AD and DE), respectively] on the performance of 42 plant species occurring in the Bavarian Alps (Germany) along an elevational gradient of 600-2000 m a.s.l. in terms of vegetative growth and reproduction performance. We demonstrate that plant vegetative and generative traits respond differently to the simulated ECEs, but the nature and magnitude treatment effects strongly depend on study site location along the elevational gradient, species' altitudinal origin and plant functional type (PFT) of the target species. For example, the negative effect of DR treatment on growth (e.g., lower growth rates and lower leaf nitrogen content) and reproduction (e.g., lower seed mass) was much stronger in upland sites, as compared to lowlands. Species' response to the treatments also differed according to their altitudinal origin. Specifically, upland species responded negatively to extreme DR (e.g., lower growth rates and lower leaf carbon concentrations, smaller seed set), whereas performance of lowland species remained unaffected (e.g., stable seed set and seed size) or even positively responded (e.g., higher growth rates) to that treatment. Furthermore, we were able to detect some consistent differences in responses to the ECEs among three PFTs (forbs, graminoids, and legumes). For instance, vegetative growth and sexual reproduction of highly adaptable opportunistic graminoids positively responded to nearly all ECEs, likely on the costs of other, more conservative, forbs and legumes. Our results suggest that ECEs can significantly modify the performance of specific plant groups and therefore lead to changes in plant community structure and composition under ongoing climate change. Our study therefore underlines the need for more experimental studies on the effects of extreme climate events to understand the potential consequences of climate change for the alpine ecosystem.

Spatial and seasonal variations in mobile carbohydrates in Pinus cembra in the timberline ecotone of the Central Austrian Alps.

PubMed

Gruber, A; Pirkebner, D; Oberhuber, W; Wieser, G

2011-03-01

To test whether the altitudinal limit of tree growth is determined by carbons shortage or by a limitation in growth we investigated non structural carbohydrates and their components starch and total soluble sugars in Pinus cembra trees along an elevational gradient in the timberline ecotone of the Central Austrian Alps. NSC contents in needles, branches, stems, and coarse roots were measured throughout an entire growing season. At the tissue level NSC contents were not significantly more abundant in treeline trees as compared to trees at lower elevations. Along our 425 m elevational transect from the closed forest to the treeline we failed to find a stable elevational trend in the total NSC pool of entire trees and observed within season increases in the tree's NSC pool that can be attributed to an altitudinal increase in leaf mass as needles contained the largest NSC fraction of the whole tree NSC pool. Furthermore, whole tree NSC contents were positively correlated with net photosynthetic capacity. Although our observed NSC characteristics do not support the hypothesis that tree life at their upper elevational limit is determined by an insufficient carbon balance we found no consistent confirmation for the sink limitation hypothesis.

Spatial and seasonal variations in mobile carbohydrates in Pinus cembra in the timberline ecotone of the Central Austrian Alps

PubMed Central

Gruber, A.; Pirkebner, D.; Oberhuber, W.; Wieser, G.

2011-01-01

To test whether the altitudinal limit of tree growth is determined by carbons shortage or by a limitation in growth we investigated non structural carbohydrates and their components starch and total soluble sugars in Pinus cembra trees along an elevational gradient in the timberline ecotone of the Central Austrian Alps. NSC contents in needles, branches, stems, and coarse roots were measured throughout an entire growing season. At the tissue level NSC contents were not significantly more abundant in treeline trees as compared to trees at lower elevations. Along our 425 m elevational transect from the closed forest to the treeline we failed to find a stable elevational trend in the total NSC pool of entire trees and observed within season increases in the tree’s NSC pool that can be attributed to an altitudinal increase in leaf mass as needles contained the largest NSC fraction of the whole tree NSC pool. Furthermore, whole tree NSC contents were positively correlated with net photosynthetic capacity. Although our observed NSC characteristics do not support the hypothesis that tree life at their upper elevational limit is determined by an insufficient carbon balance we found no consistent confirmation for the sink limitation hypothesis. PMID:22003357

Corridor- and stopover-use of the Hawaiian goose (Branta sandvicensis), an intratropical altitudinal migrant

USGS Publications Warehouse

Leopold, Christina R.; Hess, Steven C.

2014-01-01

We outfitted six male Hawaiian geese, or nene (Branta sandvicensis), with 45-g solar-powered satellite transmitters and collected four location coordinates d−1 from 2010 to 2012. We used 6193 coordinates to characterize migration corridors, habitat preferences and temporal patterns of displacement for 16 migration events with Brownian bridge utilization distributions (BBUD). We used 1552 coordinates to characterize stopovers from 37 shorter-distance movement events with 25% BBUDs. Two subpopulations used a well-defined common migration corridor spanning a broad gradient of elevation. Use of native-dominated subalpine shrubland was 2.81 times more likely than the availability of this land-cover type. The nene differed from other tropical and temperate-zone migrant birds in that: (1) migration distance and the number of stopovers were unrelated (Mann–Whitney test W = 241, P < 0.006), and; (2) individual movements were not unidirectional suggesting that social interactions may be more important than refuelling en route; but like other species, nene made more direct migrations with fewer stopovers in return to breeding areas (0.58 ± 0.50) than in migration away from breeding areas (1.64 ± 0.48). Our findings, combined with the direction and timing of migration, which is opposite that of most other intratropical migrants, suggest fundamentally different drivers of altitudinal migration.

Testate amoebae (Protista) communities in Hylocomium splendens (Hedw.) B.S.G. (Bryophyta): relationships with altitude, and moss elemental chemistry.

PubMed

Mitchell, Edward A D; Bragazza, Luca; Gerdol, Renato

2004-12-01

We studied the testate amoebae in the moss Hylocomium splendens along an altitudinal gradient from 1000 to 2200 m asl. in the south-eastern Alps of Italy in relation to micro- and macro-nutrient content of moss plants. Three mountainous areas were chosen, two of them characterised by calcareous bedrock, the third by siliceous bedrock. A total of 25 testate amoebae taxa were recorded, with a mean species richness of 9.3 per sampling plot. In a canonical correspondence analysis, 63.1% of the variation in the amoebae data was explained by moss tissue chemistry, namely by C, P, Ca, Mg, Al, Fe, and Na content and a binary site variable. We interpreted this result as an indirect effect of moss chemistry on testate amoebae through an influence on prey organisms. Although two species responded to altitude, there was no overall significant relationship between testate amoebae diversity or community structure and altitude, presumably because our sampling protocol aimed at minimizing the variability due to vegetation types and soil heterogeneity. This suggests that previous evidence of altitudinal or latitudinal effects on testate amoebae diversity may at least in part be due to a sampling bias, namely differences in soil type or moss species sampled.

Patterns of Genetic Variation across Altitude in Three Plant Species of Semi-Dry Grasslands

PubMed Central

Hahn, Thomas; Kettle, Chris J.; Ghazoul, Jaboury; Frei, Esther R.; Matter, Philippe; Pluess, Andrea R.

2012-01-01

Background Environmental gradients caused by altitudinal gradients may affect genetic variation within and among plant populations and inbreeding within populations. Populations in the upper range periphery of a species may be important source populations for range shifts to higher altitude in response to climate change. In this study we investigate patterns of population genetic variation at upper peripheral and lower more central altitudes in three common plant species of semi-dry grasslands in montane landscapes. Methodology/Principal Findings In Briza media, Trifolium montanum and Ranunculus bulbosus genetic diversity, inbreeding and genetic relatedness of individuals within populations and genetic differentiation among populations was characterized using AFLP markers. Populations were sampled in the Swiss Alps at 1800 (upper periphery of the study organisms) and at 1200 m a.s.l. Genetic diversity was not affected by altitude and only in B. media inbreeding was greater at higher altitudes. Genetic differentiation was slightly greater among populations at higher altitudes in B. media and individuals within populations were more related to each other compared to individuals in lower altitude populations. A similar but less strong pattern of differentiation and relatedness was observed in T. montanum, while in R. bulbosus there was no effect of altitude. Estimations of population size and isolation of populations were similar, both at higher and lower altitudes. Conclusions/Significance Our results suggest that altitude does not affect genetic diversity in the grassland species under study. Genetic differentiation of populations increased only slightly at higher elevation, probably due to extensive (historic) gene flow among altitudes. Potentially pre-adapted genes might therefore spread easily across altitudes. Our study indicates that populations at the upper periphery are not genetically depauperate or isolated and thus may be important source populations for migration under climate change. PMID:22870236

Genetic responses to seasonal variation in altitudinal stress: whole-genome resequencing of great tit in eastern Himalayas

PubMed Central

Qu, Yanhua; Tian, Shilin; Han, Naijian; Zhao, Hongwei; Gao, Bin; Fu, Jun; Cheng, Yalin; Song, Gang; Ericson, Per G. P.; Zhang, Yong E.; Wang, Dawei; Quan, Qing; Jiang, Zhi; Li, Ruiqiang; Lei, Fumin

2015-01-01

Species that undertake altitudinal migrations are exposed to a considerable seasonal variation in oxygen levels and temperature. How they cope with this was studied in a population of great tit (Parus major) that breeds at high elevations and winters at lower elevations in the eastern Himalayas. Comparison of population genomics of high altitudinal great tits and those living in lowlands revealed an accelerated genetic selection for carbohydrate energy metabolism (amino sugar, nucleotide sugar metabolism and insulin signaling pathways) and hypoxia response (PI3K-akt, mTOR and MAPK signaling pathways) in the high altitudinal population. The PI3K-akt, mTOR and MAPK pathways modulate the hypoxia-inducible factors, HIF-1α and VEGF protein expression thus indirectly regulate hypoxia induced angiogenesis, erythropoiesis and vasodilatation. The strategies observed in high altitudinal great tits differ from those described in a closely related species on the Tibetan Plateau, the sedentary ground tit (Parus humilis). This species has enhanced selection in lipid-specific metabolic pathways and hypoxia-inducible factor pathway (HIF-1). Comparative population genomics also revealed selection for larger body size in high altitudinal great tits. PMID:26404527

Variations in pollen counts largely explained by climate and weather

NASA Astrophysics Data System (ADS)

Jung, Stephan; Damialis, Athanasios; Estrella, Nicole; Jochner, Susanne; Menzel, Annette

2017-04-01

The interaction between climate and vegetation is well studied within phenology. Climatic / weather conditions affect e.g. flowering date, length of vegetation period, start and end of the season and the plant growth. Besides phenological stages also pollen counts can be used to investigate the interaction between climate and vegetation. Pollen emission and distribution is directly influenced by temperature, wind speed, wind direction and humidity/precipitation. The objective of this project is to study daily/sub daily variations in pollen counts of woody and herbaceous plant species along an altitudinal gradient with different climatic conditions during the vegetation period. Measurements of pollen were carried out with three volumetric pollen traps installed at the altitudes 450 m a.s.l (Freising), 700 m a.s.l (Garmisch-Partenkirchen), and 2700 m a.s.l (Schneefernerhaus near Zugspitze) representing gradient from north of Munich towards the highest mountain of Germany. Airborne pollen concentrations were recorded during the years 2014-2015. The altitudinal range of these three stations accompanied by different microclimates ("space for time approach") can be used as proxy for climate change and to assess its impact on pollen counts and thus allergenic risk for human health. For example the pollen season is shortened and pollen amount is reduced at higher sites. For detailed investigations pollen of the species Plantago, Quercus, Poaceae, Cupressaceae, Cyperacea, Betula and Platanus were chosen, because those are found in appropriate quantities. In general, pollen captured in the pollen traps to a certain extent has its origin from the immediate surrounding. Thus, it mirrors local species distribution. But furthermore the distance of pollen transport is also based on (micro-) climatic conditions, land cover and topography. The pollen trap shortly below the summit of Zugspitze (Schneefernerhaus) has an alpine environment without vegetation nearby. Therefore, this trap can be used to detect short-, middle- and long-range pollen transport. The pollen trap in Garmisch-Partenkirchen is located in the valley below Zugspitze making these two stations suitable for a direct comparison. First results show that the total amount of pollen at Schneefernerhaus for Plantago, Quercus, Poaceae, Cupressaceae, Cyperaceae and Betula is only about 20% in comparison to Garmisch. Furthermore there are daily differences in the pollen counts in yearly sum between morning (24:00 -12:00) and afternoon (12:00- 24:00). This phenomenon might be caused by diurnal climatic variations in the boundary layer as well as local mountain wind systems (changing wind direction from morning to afternoon time). Additionally pollen counts were linked to weather data recorded by the German Meteorological Service and local climate stations. Results indicate that the duration of precipitation events is a major factor of influence concerning the counted pollen. With increasing duration of a rain event pollen counts are decreasing.

Estimating home-range size: when to include a third dimension?

PubMed Central

Monterroso, Pedro; Sillero, Neftalí; Rosalino, Luís Miguel; Loureiro, Filipa; Alves, Paulo Célio

2013-01-01

Most studies dealing with home ranges consider the study areas as if they were totally flat, working only in two dimensions, when in reality they are irregular surfaces displayed in three dimensions. By disregarding the third dimension (i.e., topography), the size of home ranges underestimates the surface actually occupied by the animal, potentially leading to misinterpretations of the animals' ecological needs. We explored the influence of considering the third dimension in the estimation of home-range size by modeling the variation between the planimetric and topographic estimates at several spatial scales. Our results revealed that planimetric approaches underestimate home-range size estimations, which range from nearly zero up to 22%. The difference between planimetric and topographic estimates of home-ranges sizes produced highly robust models using the average slope as the sole independent factor. Moreover, our models suggest that planimetric estimates in areas with an average slope of 16.3° (±0.4) or more will incur in errors ≥5%. Alternatively, the altitudinal range can be used as an indicator of the need to include topography in home-range estimates. Our results confirmed that home-range estimates could be significantly biased when topography is disregarded. We suggest that study areas where home-range studies will be performed should firstly be scoped for its altitudinal range, which can serve as an indicator for the need for posterior use of average slope values to model the surface area used and/or available for the studied animals. PMID:23919170

Quercus kelloggii Newb., California black oak

Treesearch

P.M. McDonald

1990-01-01

California black oak (Quercus kelloggii) exceeds all other California oaks in volume, distribution, and altitudinal range. Yet this deciduous hardwood has had little sustained commercial use and almost no management, even though its wood closely resembles that of its valuable, managed, and heavily used counterpart-northern red oak (...

Scaling relationships of twig biomass allocation in Pinus hwangshanensis along an altitudinal gradient

PubMed Central

Li, Man; Zheng, Yuan; Fan, RuiRui; Zhong, QuanLin; Cheng, DongLiang

2017-01-01

Understanding the response of biomass allocation in twigs (the terminal branches of current-year shoots) to environmental change is crucial for elucidating forest ecosystem carbon storage, carbon cycling, and plant life history strategies under a changing climate. On the basis of interspecies investigations of broad-leaved plants, previous studies have demonstrated that plants respond to environmental factors by allocating biomass in an allometric manner between support tissues (i.e., stems) and the leaf biomass of twigs, where the scaling exponent (i.e., slope of a log—log linear relationship, α) is constant, and the scaling constant (i.e., intercept of a log—log linear relationship, log β) varies with respect to environmental factors. However, little is known about whether the isometric scaling exponents of such biomass allocations remain invariant for single species, particularly conifers, at different altitudes and in different growing periods. In this study, we investigated how twig biomass allocation varies with elevation and period among Pinus hwangshanensis Hsia trees growing in the mountains of Southeast China. Specifically, we explored how twig stem mass, needle mass, and needle area varied throughout the growing period (early, mid-, late) and at three elevations in the Wuyi Mountains. Standardized major axis analysis was used to compare the scaling exponents and scaling constants between the biomass allocations of within-twig components. Scaling relationships between these traits differed with growing period and altitude gradient. During the different growing periods, there was an isometric scaling relationship, with a common slope of 1.0 (i.e., α ≈ 1.0), between needle mass and twig mass (the sum of the total needle mass and the stem mass), whereas there were allometric scaling relationships between the stem mass and twig mass and between the needle mass and stem mass of P. hwangshanensis. The scaling constants (log β) for needle mass vs. twig mass and for needle mass vs. stem mass increased progressively across the growing stages, whereas the scaling constants of stem mass vs. twig mass showed the opposite pattern. The scaling exponents (α) of needle area with respect to needle biomass increased significantly with growing period, changing from an allometric relationship (i.e., α < 1.0) during the early growing period to a nearly isometric relationship (i.e., α ≈ 1.0) during the late growing period. This change possibly reflects the functional adaptation of twigs in different growing periods to meet their specific reproductive or survival needs. At different points along the altitudinal gradient, the relationships among needle mass, twig mass, and stem mass were all isometric (i.e., α ≈ 1.0). Moreover, significant differences were found in scaling constants (log β) along the altitudinal gradient, such that species had a smaller stem biomass but a relatively larger needle mass at low altitude. In addition, the scaling exponents remained numerically invariant among all three altitudes, with a common slope of 0.8, suggesting that needle area failed to keep pace with the increasing needle mass at different altitudes. Our results indicated that the twig biomass allocation pattern was significantly influenced by altitude and growing period, which reflects the functional adaptation of twigs to meet their specific survival needs under different climatic conditions. PMID:28552954

Scaling relationships of twig biomass allocation in Pinus hwangshanensis along an altitudinal gradient.

PubMed

Li, Man; Zheng, Yuan; Fan, RuiRui; Zhong, QuanLin; Cheng, DongLiang

2017-01-01

Understanding the response of biomass allocation in twigs (the terminal branches of current-year shoots) to environmental change is crucial for elucidating forest ecosystem carbon storage, carbon cycling, and plant life history strategies under a changing climate. On the basis of interspecies investigations of broad-leaved plants, previous studies have demonstrated that plants respond to environmental factors by allocating biomass in an allometric manner between support tissues (i.e., stems) and the leaf biomass of twigs, where the scaling exponent (i.e., slope of a log-log linear relationship, α) is constant, and the scaling constant (i.e., intercept of a log-log linear relationship, log β) varies with respect to environmental factors. However, little is known about whether the isometric scaling exponents of such biomass allocations remain invariant for single species, particularly conifers, at different altitudes and in different growing periods. In this study, we investigated how twig biomass allocation varies with elevation and period among Pinus hwangshanensis Hsia trees growing in the mountains of Southeast China. Specifically, we explored how twig stem mass, needle mass, and needle area varied throughout the growing period (early, mid-, late) and at three elevations in the Wuyi Mountains. Standardized major axis analysis was used to compare the scaling exponents and scaling constants between the biomass allocations of within-twig components. Scaling relationships between these traits differed with growing period and altitude gradient. During the different growing periods, there was an isometric scaling relationship, with a common slope of 1.0 (i.e., α ≈ 1.0), between needle mass and twig mass (the sum of the total needle mass and the stem mass), whereas there were allometric scaling relationships between the stem mass and twig mass and between the needle mass and stem mass of P. hwangshanensis. The scaling constants (log β) for needle mass vs. twig mass and for needle mass vs. stem mass increased progressively across the growing stages, whereas the scaling constants of stem mass vs. twig mass showed the opposite pattern. The scaling exponents (α) of needle area with respect to needle biomass increased significantly with growing period, changing from an allometric relationship (i.e., α < 1.0) during the early growing period to a nearly isometric relationship (i.e., α ≈ 1.0) during the late growing period. This change possibly reflects the functional adaptation of twigs in different growing periods to meet their specific reproductive or survival needs. At different points along the altitudinal gradient, the relationships among needle mass, twig mass, and stem mass were all isometric (i.e., α ≈ 1.0). Moreover, significant differences were found in scaling constants (log β) along the altitudinal gradient, such that species had a smaller stem biomass but a relatively larger needle mass at low altitude. In addition, the scaling exponents remained numerically invariant among all three altitudes, with a common slope of 0.8, suggesting that needle area failed to keep pace with the increasing needle mass at different altitudes. Our results indicated that the twig biomass allocation pattern was significantly influenced by altitude and growing period, which reflects the functional adaptation of twigs to meet their specific survival needs under different climatic conditions.

Changing climate and the altitudinal range of avian malaria in the Hawaiian Islands: an ongoing conservation crisis on the island of Kaua'i

USGS Publications Warehouse

Atkinson, Carter T.; Utzurrum, Ruth B.; LaPointe, Dennis A.; Camp, Richard J.; Crampton, Lisa H.; Foster, Jeffrey T.; Giambelluca, Thomas W.

2014-01-01

Transmission of avian malaria in the Hawaiian Islands varies across altitudinal gradients and is greatest at elevations below 1500 m where both temperature and moisture are favorable for the sole mosquito vector, Culex quinquefasciatus, and extrinsic sporogonic development of the parasite, Plasmodium relictum. Potential consequences of global warming on this system have been recognized for over a decade with concerns that increases in mean temperatures could lead to expansion of malaria into habitats where cool temperatures currently limit transmission to highly susceptible endemic forest birds. Recent declines in two endangered species on the island of Kaua'i, the ‘Akikiki (Oreomystis bairdi) and ‘Akeke'e (Loxops caeruleirostris), and retreat of more common native honeycreepers to the last remaining high elevation habitat on the Alaka'i Plateau suggest that predicted changes in disease transmission may be occurring. We compared prevalence of malarial infections in forest birds that were sampled at three locations on the Plateau during 1994–1997 and again during 2007–2013, and also evaluated changes in the occurrence of mosquito larvae in available aquatic habitats during the same time periods. Prevalence of infection increased significantly at the lower (1100 m, 10.3% to 28.2%), middle (1250 m, 8.4% to 12.2%), and upper ends of the Plateau (1350 m, 2.0% to 19.3%). A concurrent increase in detections of Culex larvae in aquatic habitats associated with stream margins indicates that populations of the vector are also increasing. These increases are at least in part due to local transmission because overall prevalence in Kaua'i ‘Elepaio (Chasiempis sclateri), a sedentary native species, has increased from 17.2% to 27.0%. Increasing mean air temperatures, declining precipitation, and changes in streamflow that have taken place over the past 20 years are creating environmental conditions throughout major portions of the Alaka'i Plateau that support increased transmission of avian malaria.

Changing climate and the altitudinal range of avian malaria in the Hawaiian Islands - an ongoing conservation crisis on the island of Kaua'i.

PubMed

Atkinson, Carter T; Utzurrum, Ruth B; Lapointe, Dennis A; Camp, Richard J; Crampton, Lisa H; Foster, Jeffrey T; Giambelluca, Thomas W

2014-08-01

Transmission of avian malaria in the Hawaiian Islands varies across altitudinal gradients and is greatest at elevations below 1500 m where both temperature and moisture are favorable for the sole mosquito vector, Culex quinquefasciatus, and extrinsic sporogonic development of the parasite, Plasmodium relictum. Potential consequences of global warming on this system have been recognized for over a decade with concerns that increases in mean temperatures could lead to expansion of malaria into habitats where cool temperatures currently limit transmission to highly susceptible endemic forest birds. Recent declines in two endangered species on the island of Kaua'i, the 'Akikiki (Oreomystis bairdi) and 'Akeke'e (Loxops caeruleirostris), and retreat of more common native honeycreepers to the last remaining high elevation habitat on the Alaka'i Plateau suggest that predicted changes in disease transmission may be occurring. We compared prevalence of malarial infections in forest birds that were sampled at three locations on the Plateau during 1994-1997 and again during 2007-2013, and also evaluated changes in the occurrence of mosquito larvae in available aquatic habitats during the same time periods. Prevalence of infection increased significantly at the lower (1100 m, 10.3% to 28.2%), middle (1250 m, 8.4% to 12.2%), and upper ends of the Plateau (1350 m, 2.0% to 19.3%). A concurrent increase in detections of Culex larvae in aquatic habitats associated with stream margins indicates that populations of the vector are also increasing. These increases are at least in part due to local transmission because overall prevalence in Kaua'i 'Elepaio (Chasiempis sclateri), a sedentary native species, has increased from 17.2% to 27.0%. Increasing mean air temperatures, declining precipitation, and changes in streamflow that have taken place over the past 20 years are creating environmental conditions throughout major portions of the Alaka'i Plateau that support increased transmission of avian malaria. © 2014 John Wiley & Sons Ltd.

Mitochondrial DNA markers reveal high genetic diversity but low genetic differentiation in the black fly Simulium tani Takaoka & Davies along an elevational gradient in Malaysia.

PubMed

Low, Van Lun; Adler, Peter H; Takaoka, Hiroyuki; Ya'cob, Zubaidah; Lim, Phaik Eem; Tan, Tiong Kai; Lim, Yvonne A L; Chen, Chee Dhang; Norma-Rashid, Yusoff; Sofian-Azirun, Mohd

2014-01-01

The population genetic structure of Simulium tani was inferred from mitochondria-encoded sequences of cytochrome c oxidase subunits I (COI) and II (COII) along an elevational gradient in Cameron Highlands, Malaysia. A statistical parsimony network of 71 individuals revealed 71 haplotypes in the COI gene and 43 haplotypes in the COII gene; the concatenated sequences of the COI and COII genes revealed 71 haplotypes. High levels of genetic diversity but low levels of genetic differentiation were observed among populations of S. tani at five elevations. The degree of genetic diversity, however, was not in accordance with an altitudinal gradient, and a Mantel test indicated that elevation did not have a limiting effect on gene flow. No ancestral haplotype of S. tani was found among the populations. Pupae with unique structural characters at the highest elevation showed a tendency to form their own haplotype cluster, as revealed by the COII gene. Tajima's D, Fu's Fs, and mismatch distribution tests revealed population expansion of S. tani in Cameron Highlands. A strong correlation was found between nucleotide diversity and the levels of dissolved oxygen in the streams where S. tani was collected.

Altitude effects on technology and productivity of small bovine farms (milk meat) in Veracruz (Gulf of Mexico).

PubMed

Ruíz-Guevara, C; De León-González, F; Soriano-Robles, R; Pérez-Carrera, A L; García-Hernández, L A

2018-03-01

The dual-purpose bovine system represents 98.4% of the bovine livestock of Veracruz, the main cattle-producing state of Mexico. This system supplies calves to meat companies, a sector in which Veracruz has been the national leader in the last decade. The objective of the present study was to analyze the effect of the altitudinal zonation of farms on livestock technology and productivity in a microbasin of the Gulf of Mexico where small farms predominate. Structured interviews were applied to producers located in three altitudinal zones (at average altitudes of 50, 140, and 450 m, respectively, for lower, middle, and upper zones). Sample size was 135 farms having similar land surface (within a range of 15-22 ha). The results indicated multiple differences among farms located in the three zones. Farms in the middle and lower zones presented higher productive indicators than those in the upper zone. Differences in herd structure and management resulted in important differences in productivity, income, and profits in milk and calf production. We concluded from this study that altitudinal zonation in Veracruz had a clear effect on the differentiation of small farms, which are representative of dual-purpose cattle. The upper zone performs cattle activity under conditions with greater disadvantages in the analyzed region.

Globally invasive, withdrawing at home: Aedes albopictus and Aedes japonicus facing the rise of Aedes flavopictus

NASA Astrophysics Data System (ADS)

Chaves, Luis Fernando

2016-11-01

It has been suggested that climate change may have facilitated the global expansion of invasive disease vectors, since several species have expanded their range as temperatures have warmed. Here, we present results from observations on two major global invasive mosquito vectors (Diptera: Culicidae), Aedes albopictus (Skuse) and Aedes japonicus (Theobald), across the altitudinal range of Mt. Konpira, Nagasaki, Japan, a location within their native range, where Aedes flavopictus Yamada, formerly a rare species, has now become dominant. Spatial abundance patterns of the three species suggest that temperature is an important factor influencing their adult distribution across the altitudinal range of Mt. Konpira. Temporal abundance patterns, by contrast, were associated with rainfall and showed signals of density-dependent regulation in the three species. The spatial and temporal analysis of abundance patterns showed that Ae. flavopictus and Ae. albopictus were negatively associated, even when accounting for differential impacts of weather and other environmental factors in their co-occurrence patterns. Our results highlight a contingency in the expansion of invasive vectors, the potential emergence of changes in their interactions with species in their native communities, and raise the question of whether these changes might be useful to predict the emergence of future invasive vectors.

Empirical relationship between leaf wax n-alkane δD and altitude in the Wuyi, Shennongjia and Tianshan Mountains, China: Implications for paleoaltimetry

NASA Astrophysics Data System (ADS)

Luo, Pan; Peng, Ping'an; Gleixner, Gerd; Zheng, Zhuo; Pang, Zhonghe; Ding, Zhongli

2011-01-01

Estimating past elevation not only provides evidence for vertical movements of the Earth's lithosphere, but also increases our understanding of interactions between tectonics, relief and climate in geological history. Development of biomarker hydrogen isotope-based paleoaltimetry techniques that can be applied to a wide range of sample types is therefore of continuing importance. Here we present leaf wax-derived n-alkane δD (δDwax) values along three soil altitudinal transects, at different latitudes, in the Wuyi, Shennongjia and Tianshan Mountains in China, to investigate δDwax gradients and the apparent fractionation between leaf wax and precipitation (εwax-p). We find that soil δDwax track altitudinal variations of precipitation δD along the three transects that span variable environment conditions and vertical vegetation spectra. An empirical δDwax-altitude relation is therefore established in which the average δDwax lapse rate of - 2.27 ± 0.38‰/100 m is suitable for predicting relative paleoelevation change (relative uplift). The application of this empirical gradient is restricted to phases in the mountain uplift stage when the atmospheric circulation had not distinctly changed and to when the climate was not arid. An empirical δDwax-latitude-altitude formula is also calculated: δDwax = 3.483LAT - 0.0227ALT - 261.5, which gives the preliminary spatial distribution pattern of δDwax in modern China. Mean value of εwax-p in the extreme humid Wuyi Mountains is quite negative (- 154‰), compared to the humid Shennongjia (- 129‰) and the arid (but with abundant summer precipitation) Tianshan Mountains (- 130‰), which suggests aridity or water availability in the growing season is the primary factor controlling soil/sediment εwax-p. Along the Tianshan transects, values of εwax-p are speculated to be constant with altitude; while along the Wuyi and Shennongjia transects, εwax-p are also constant at the low-mid altitudes, but become slightly more negative at high altitudes which could be attributed to overestimates of precipitation δD or the vegetation shift to grass/conifer. Additionally, a reversal of altitude effect in the vertical variation of δDwax was found in the alpine zone of the Tianshan Mountains, which might be caused by atmospheric circulation change with altitude. This implies that the paleo-circulation pattern and its changes should also be evaluated when stable isotope-based paleoaltimetry is applied.

Evaluation of the impact of frost resistances on potential altitudinal limit of trees.

PubMed

Charrier, Guillaume; Cochard, Hervé; Améglio, Thierry

2013-09-01

Winter physiology of woody plants is a key issue in temperate biomes. Here, we investigated different frost resistance mechanisms on 1-year-old branches of 11 European tree species from November until budburst: (i) frost hardiness of living cells (by electrolyte leakage method), (ii) winter embolism sensitivity (by percentage loss of conductivity: PLC) and (iii) phenological variation of budburst (by thermal time to budburst). These ecophysiological traits were analyzed according to the potential altitudinal limit, which is highly related to frost exposure. Seasonal frost hardiness and PLC changes are relatively different across species. Maximal PLC observed in winter (PLCMax) was the factor most closely related to potential altitudinal limit. Moreover, PLCMax was related to the mean hydraulic diameter of vessels (indicating embolism sensitivity) and to osmotic compounds (indicating ability of living cells to refill xylem conducting elements). Winter embolism formation seems to be counterbalanced by active refilling from living cells. These results enabled us to model potential altitudinal limit according to three of the physiological/anatomical parameters studied. Monitoring different frost resistance strategies brings new insights to our understanding of the altitudinal limits of trees.

ncreasing altitudinal spring phenology gradient of vegetation over the last decade in Qinghai-Tibetan Plateau

NASA Astrophysics Data System (ADS)

Shen, M.; Piao, S.

2013-12-01

Vegetation spring phenology in temperate and cold regions is widely expected to advance with temperature elevation and is often used as an indicator of regional climatic change. The Qinghai-Tibetan Plateau (QTP) has experienced intensive warming recently, but substantial contradictions exist about the changes of vegetation spring phenology. We investigated spatiotemporal variations in green-up dates in the QTP from 2000 to 2011 determined through five methods using four satellite-derived datasets including the normalized difference vegetation index (NDVI) from the Advanced Very High Resolution Radiometer (AVHRR), Système Pour l'Observation de la Terre, and MODerate resolution Imaging Spectroradiometer (MODIS), and the enhanced vegetation index from MODIS. On regional scale, no significant temporal trends (all P > 0.05) were found in the green-up dates, consistently among all the vegetation indices and methods. This insignificance was resulted from the substantial spatial heterogeneity of trends in green-up date, with delay by greater than 0.5 day yr-1 in the southwest region, and extensive advance in the other areas, although the temperature elevation was region-wide. These changes doubled the altitudinal gradient of green-up date, from 0.63 day 100m-1 in the early 2000s to 1.30 days 100m-1 in the early 2010s. The delay in the southwest region and high altitudes was likely caused by the decline in spring precipitation, despite the increasing spring temperature. This study suggests that spring precipitation is an important regulator of phenological response to climatic warming in QTP, and that, even in cold region, delay of vegetation spring phenology does not necessarily indicate spring cooling. Besides, the phenological changes retrieved from the widely used AVHRR NDVI differed from those from the other 3 vegetation indices, necessitating the use of multi-datasets while monitoring vegetation dynamics from space.

The effects of biotic and abiotic factors on the spatial heterogeneity of alpine grassland vegetation at a small scale on the Qinghai-Tibet Plateau (QTP), China.

PubMed

Wen, Lu; Dong, Shi Kui; Li, Yuan Yuan; Sherman, Ruth; Shi, Jian Jun; Liu, De Mei; Wang, Yan Long; Ma, Yu Shou; Zhu, Lei

2013-10-01

Understanding the complex effects of biotic and abiotic factors on the composition of vegetation is very important for developing and implementing strategies for promoting sustainable grassland development. The vegetation-disturbance-environment relationship was examined in degraded alpine grasslands in the headwater areas of three rivers on the Qinghai-Tibet Plateau in this study. The investigated hypotheses were that (1) the heterogeneity of the vegetation of the alpine grassland is due to a combination of biotic and abiotic factors and that (2) at a small scale, biotic factors are more important for the distribution of alpine vegetation. On this basis, four transects were set along altitudinal gradients from 3,770 to 3,890 m on a sunny slope, and four parallel transects were set along altitudinal gradients on a shady slope in alpine grasslands in Guoluo Prefecture of Qinghai Province, China. It was found that biological disturbances were the major forces driving the spatial heterogeneity of the alpine grassland vegetation and abiotic factors were of secondary importance. Heavy grazing and intensive rat activity resulted in increases in unpalatable and poisonous weeds and decreased fine forages in the form of sedges, forbs, and grasses in the vegetation composition. Habitat degradation associated with biological disturbances significantly affected the spatial variation of the alpine grassland vegetation, i.e., more pioneer plants of poisonous or unpalatable weed species, such as Ligularia virgaurea and Euphorbia fischeriana, were found in bare patches. Environmental/abiotic factors were less important than biological disturbances in affecting the spatial distribution of the alpine grassland vegetation at a small scale. It was concluded that rat control and light grazing should be applied first in implementing restoration strategies. The primary vegetation in lightly grazed and less rat-damaged sites should be regarded as a reference for devising vegetation restoration measures in alpine pastoral regions.

Foliar δ13C Showed No Altitudinal Trend in an Arid Region and Atmospheric Pressure Exerted a Negative Effect on Plant δ13C.

PubMed

Chen, Zixun; Wang, Guoan; Jia, Yufu

2017-01-01

Previous studies have suggested foliar δ 13 C generally increases with altitude. However, some observations reported no changes or even decreased trends in foliar δ 13 C. We noted that all the studies in which δ 13 C increased with elevation were conducted in the human regions, whereas those investigations in which δ 13 C did not vary or decreased were conducted in areas with water stress. Thus, we proposed that the pattern of increasing δ 13 C with elevation is not a general one, and that δ 13 C may remain unchanged or decrease in plants grown in arid environments. To test the hypothesis, we sampled plants along altitude gradients on the shady and sunny slopes of Mount Tianshan characterized by arid and semiarid climates. The measurements of foliar δ 13 C showed no altitudinal trends for the plants grown on either of the slopes. Therefore, this study supported our hypothesis. In addition, the present study addressed the effect of atmospheric pressure on plant δ 13 C by accounting for the effects of temperature and precipitation on δ 13 C. This study found that the residual foliar δ 13 C increased with increasing altitude, suggesting that atmospheric pressure played a negative role in foliar δ 13 C.

Fine-scale population genetic structure of a wildlife disease vector: The southern house mosquito on the island of Hawaii

USGS Publications Warehouse

Keyghobadi, N.; LaPointe, D.; Fleischer, R.C.; Fonseca, D.M.

2006-01-01

The southern house mosquito, Culex quinquefasciatus, is a widespread tropical and subtropical disease vector. In the Hawaiian Islands, where it was introduced accidentally almost two centuries ago, it is considered the primary vector of avian malaria and pox. Avian malaria in particular has contributed to the extinction and endangerment of Hawaii's native avifauna, and has altered the altitudinal distribution of native bird populations. We examined the population genetic structure of Cx. quinquefasciatus on the island of Hawaii at a smaller spatial scale than has previously been attempted, with particular emphasis on the effects of elevation on population genetic structure. We found significant genetic differentiation among populations and patterns of isolation by distance within the island. Elevation per se did not have a limiting effect on gene flow; however, there was significantly lower genetic diversity among populations at mid elevations compared to those at low elevations. A recent sample taken from just above the predicted upper altitudinal distribution of Cx. quinquefasciatus on the island of Hawaii was confirmed as being a temporary summer population and appeared to consist of individuals from more than one source population. Our results indicate effects of elevation gradients on genetic structure that are consistent with known effects of elevation on population dynamics of this disease vector. ?? 2006 The Authors.

Photosynthetic temperature adaptation of Pinus cembra within the timberline ecotone of the Central Austrian Alps

PubMed Central

Wieser, Gerhard; Oberhuber, Walter; Walder, Lisa; Spieler, Daniela; Gruber, Andreas

2011-01-01

Temperature is suggested to determine the upper limit of tree life. Therefore, future climate warming may be of importance for tree distribution within the European Alps, where low temperatures limit carbon metabolism. We focused on the effects of air and soil temperature on net photosynthesis (Pn) of Pinus cembra an evergreen climax species of the timberline ecotone of the Central Austrian Alps. Light response and temperature response curves were estimated along an altitudinal gradient ranging from the forest limit up to the krummholz limit in both summer and fall. In general, Pn was significantly lower in fall as compared to summer. Nevertheless, independent from season mean Pn values tended to increase with elevation and were positively correlated with root zone temperatures. The specific leaf area by contrast declined with increasing elevation. Furthermore, the temperature optimum of net photosynthesis declined with increasing elevation and was positively correlated with the mean maximum air temperature of the 10 days prior the date of measurement. Thus, our findings appear to reflect a long-term adaptation of the photosynthetic apparatus of Pinus cembra to the general temperature conditions with respect to elevation combined with a short term acclimation to the prevailing temperature regime. PMID:21379394

Recent invasion of the mountain birch Betula pubescens ssp. tortuosa above the treeline due to climate change: genetic and ecological study in northern Sweden.

PubMed

Truong, C; Palmé, A E; Felber, F

2007-01-01

Mountain birch, Betula pubescens ssp. tortuosa, forms the treeline in northern Sweden. A recent shift in the range of the species associated with an elevation of the treeline is commonly attributed to climate warming. Using microsatellite markers, we explored the genetic structure of populations along an altitudinal gradient close to the treeline. Low genetic differentiation was found between populations, whereas high genetic diversity was maintained within populations. High level of gene flow compensated for possible losses of genetic diversity at higher elevations and dissipated the founding effect of newly established populations above the treeline. Spatial autocorrelation analysis showed low spatial genetic structure within populations because of extensive gene flow. At the treeline, significant genetic structure within the juvenile age class at small distances did not persist in the adult age class, indicating recent expansion of young recruits due to the warming of the climate. Finally, seedling performance above the treeline was positively correlated with parameters related to temperature. These data confirm the high migration potential of the species in response to fluctuating environmental conditions and indicate that it is now invading higher altitudes due to the recent warming of the climate.

Elevational Ranges of Montane Birds and Deforestation in the Western Andes of Colombia.

PubMed

Ocampo-Peñuela, Natalia; Pimm, Stuart L

2015-01-01

Deforestation causes habitat loss, fragmentation, degradation, and can ultimately cause extinction of the remnant species. Tropical montane birds face these threats with the added natural vulnerability of narrower elevational ranges and higher specialization than lowland species. Recent studies assess the impact of present and future global climate change on species' ranges, but only a few of these evaluate the potentially confounding effect of lowland deforestation on species elevational distributions. In the Western Andes of Colombia, an important biodiversity hotspot, we evaluated the effects of deforestation on the elevational ranges of montane birds along altitudinal transects. Using point counts and mist-nets, we surveyed six altitudinal transects spanning 2200 to 2800 m. Three transects were forested from 2200 to 2800 m, and three were partially deforested with forest cover only above 2400 m. We compared abundance-weighted mean elevation, minimum elevation, and elevational range width. In addition to analysing the effect of deforestation on 134 species, we tested its impact within trophic guilds and habitat preference groups. Abundance-weighted mean and minimum elevations were not significantly different between forested and partially deforested transects. Range width was marginally different: as expected, ranges were larger in forested transects. Species in different trophic guilds and habitat preference categories showed different trends. These results suggest that deforestation may affect species' elevational ranges, even within the forest that remains. Climate change will likely exacerbate harmful impacts of deforestation on species' elevational distributions. Future conservation strategies need to account for this by protecting connected forest tracts across a wide range of elevations.

Elevational Ranges of Montane Birds and Deforestation in the Western Andes of Colombia

PubMed Central

2015-01-01

Deforestation causes habitat loss, fragmentation, degradation, and can ultimately cause extinction of the remnant species. Tropical montane birds face these threats with the added natural vulnerability of narrower elevational ranges and higher specialization than lowland species. Recent studies assess the impact of present and future global climate change on species’ ranges, but only a few of these evaluate the potentially confounding effect of lowland deforestation on species elevational distributions. In the Western Andes of Colombia, an important biodiversity hotspot, we evaluated the effects of deforestation on the elevational ranges of montane birds along altitudinal transects. Using point counts and mist-nets, we surveyed six altitudinal transects spanning 2200 to 2800m. Three transects were forested from 2200 to 2800m, and three were partially deforested with forest cover only above 2400m. We compared abundance-weighted mean elevation, minimum elevation, and elevational range width. In addition to analysing the effect of deforestation on 134 species, we tested its impact within trophic guilds and habitat preference groups. Abundance-weighted mean and minimum elevations were not significantly different between forested and partially deforested transects. Range width was marginally different: as expected, ranges were larger in forested transects. Species in different trophic guilds and habitat preference categories showed different trends. These results suggest that deforestation may affect species’ elevational ranges, even within the forest that remains. Climate change will likely exacerbate harmful impacts of deforestation on species’ elevational distributions. Future conservation strategies need to account for this by protecting connected forest tracts across a wide range of elevations. PMID:26641477

Structural and Geomorphic Controls in Altitudinal Treeline: a Case Study in the Front Ranges of the Canadian Rocky Mountains

NASA Astrophysics Data System (ADS)

Macias Fauria, M.; Johnson, E. A.

2009-12-01

Altitudinal treelines occur on mountain slopes. The geological history of mountain systems sets both the distribution of slope angles, aspects and lengths, and the physical characteristics of the bedrock and regolith on which trees have to establish and grow. We show that altitudinal treeline is largely controlled at an ecosystem level by structural and slope (i.e. gravitational) geomorphic processes operating at a range of temporal and spatial scales, which have direct influence on the hydrological properties of the substrate (affecting the trees’ water and energy budget), as well as on substrate stability, both of which affect recruitment and growth of trees. The study was conducted over a relatively large area of > 200 km2 in the Front Ranges of the Canadian Rocky Mountains, selected to contain the regional diversity of slopes and substrates, which is the result of hundreds of millions of years of sea deposition, subsequent mountain building, and deep erosion by glaciations. Very high-resolution remote sensing data (LiDAR), aerial orthophotos taken at several times since the late 1940s, and ground truthing were employed to classify the terrain into process-based geomorphic units. High resolution, landscape-scale treeline studies are able avoid potential biases in site selection (i.e. selection of sites that are not representative of the overall regional treeline), and consequently capture the coupling between trees and the environment at an ecosystem (regional) level. Moreover, explicitly accounting for slope and substrate-related processes occurring in the studied mountain region is paramount in order to understand the dynamics of trees at their altitudinal distribution limit. Presence of trees in each unit was found to be controlled by a set of parameters relevant to both hydrological and slope processes, such as contributing area, slope angle, regolith transmissivity, and aspect. Our results show no treeline advance over the last 60 years in the region, as most of the area is controlled by geological processes and not by physiological temperature thresholds. Temperature could potentially affect presence of trees at high elevations through its effects on the physical properties of the slopes on which trees grow. However, this effect is at a much longer timescale than those implied in current studies of treeline response to global warming. Finally, continuous recruitment of trees following lightning-caused wildfires during the first half of the 20th century has resulted in increased high altitude forest stand density.

Exploring the patterns of alpine vegetation of Eastern Bhutan: a case study from the Merak Himalaya.

PubMed

Jamtsho, Karma; Sridith, Kitichate

2015-01-01

A survey was conducted from March to September 2012 along the altitudinal gradient of the Jomokungkhar trail in the Merak Himalaya of Sakteng Wildlife Sanctuary to study the floristic compositions and the patterns of alpine vegetation of Eastern Bhutan. The vegetation of the sampled plots is classified into five types of communities based on the hierarchical cluster analysis at similarity index 63% viz., (1) Riverine Community; (2) Abies-Rhododendron Woodland Community; (3) Juniperus Scrub Community; (4) Rhododendron Krummholz and (5) Alpine Meadow, based on the floristic compositions. In addition, it was noticed that the fragile alpine environment of the Merak Himalaya has high plant diversity and important plants that are susceptible to the anthropogenic pressures.

Skipper Richness (Hesperiidae) Along Elevational Gradients in Brazilian Atlantic Forest.

PubMed

Carneiro, E; Mielke, O H H; Casagrande, M M; Fiedler, K

2014-02-01

Hesperiidae are claimed to be a group of elusive butterflies that need major effort for sampling, thus being frequently omitted from tropical butterfly surveys. As no studies have associated species richness patterns of butterflies with environmental gradients of high altitudes in Brazil, we surveyed Hesperiidae ensembles in Serra do Mar along elevational transects (900-1,800 m above sea level) on three mountains. Transects were sampled 11-12 times on each mountain to evaluate how local species richness is influenced by mountain region, vegetation type, and elevational zones. Patterns were also analyzed for the subfamilies, and after disregarding species that exhibit hilltopping behavior. Species richness was evaluated by the observed richness, Jacknife2 estimator and Chao 1 estimator standardized by sample coverage. Overall, 155 species were collected, but extrapolation algorithms suggest a regional richness of about 220 species. Species richness was far higher in forest than in early successional vegetation or grassland. Richness decreased with elevation, and was higher on Anhangava mountain compared with the two others. Patterns were similar between observed and extrapolated Jacknife2 richness, but vegetation type and mountain richness became altered using sample coverage standardization. Hilltopping species were more easily detected than species that do not show this behavior; however, their inclusion did neither affect estimated richness nor modify the shape of the species accumulation curve. This is the first contribution to systematically study highland butterflies in southern Brazil where all records above 1,200 m are altitudinal extensions of the known geographical ranges of skipper species in the region.

Modeling the population dynamics of Culex quinquefasciatus (Diptera: Culcidae), along an elevational gradient in Hawaii

USGS Publications Warehouse

Ahumada, Jorge A.; LaPointe, Dennis; Samuel, Michael D.

2004-01-01

We present a population model to understand the effects of temperature and rainfall on the population dynamics of the southern house mosquito, Culex quinquefasciatus Say, along an elevational gradient in Hawaii. We use a novel approach to model the effects of temperature on population growth by dynamically incorporating developmental rate into the transition matrix, by using physiological ages of immatures instead of chronological age or stages. We also model the effects of rainfall on survival of immatures as the cumulative number of days below a certain rain threshold. Finally, we incorporate density dependence into the model as competition between immatures within breeding sites. Our model predicts the upper altitudinal distributions of Cx. quinquefasciatus on the Big Island of Hawaii for self-sustaining mosquito and migrating summer sink populations at 1,475 and 1,715 m above sea level, respectively. Our model predicts that mosquitoes at lower elevations can grow under a broader range of rainfall parameters than middle and high elevation populations. Density dependence in conjunction with the seasonal forcing imposed by temperature and rain creates cycles in the dynamics of the population that peak in the summer and early fall. The model provides a reasonable fit to the available data on mosquito abundance for the east side of Mauna Loa, Hawaii. The predictions of our model indicate the importance of abiotic conditions on mosquito dynamics and have important implications for the management of diseases transmitted by Cx. quinquefasciatus in Hawaii and elsewhere.

Mycorrhizal and Dark-Septate Fungi in Plant Roots above 4270 Meters Elevation in the Andes and Rocky Mountains

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schmidt, Steven K.; Sobieniak-Wiseman, L. Cheyanne; Kageyama, Stacy A.

2008-01-01

Arbuscular mycorrhizal (AM) and dark-septate endophytic (DSE) fungi were quantified in plant roots from high-elevation sites in the Cordillera Vilcanota of the Andes (Per ) and the Front Range of the Colorado Rocky Mountains (U.S.A.). At the highest sites in the Andes (5391 m) AM fungi were absent in the two species of plants sampled (both Compositae) but roots of both were heavily colonized by DSE fungi. At slightly lower elevations (5240 5250 m) AM fungi were present in roots while DSE fungi were rare in plants outside of the composite family. At the highest sites sampled in Colorado (4300more » m) AM fungi were present, but at very low levels and all plants sampled contained DSE fungi. Hyphae of coarse AM fungi decreased significantly in plant roots at higher altitude in Colorado, but no other structures showed significant decreases with altitude. These new findings indicate that the altitudinal distribution of mycorrhizal fungi observed for European mountains do not necessarily apply to higher and drier mountains that cover much of the Earth (e.g. the Himalaya, Hindu Kush, Andes, and Rockies) where plant growth is more limited by nutrients and water than in European mountains. This paper describes the highest altitudinal records for both AM and DSE fungi, surpassing previous reported altitudinal maxima by about 1500 meters.« less

Vivid valleys, pallid peaks? Hypsometric variations and rural-urban land change in the Central Peruvian Andes.

PubMed

Haller, Andreas

2012-11-01

What happens to the land cover within the hinterland's altitudinal belts while Central Andean cities are undergoing globalization and urban restructuring? What conclusions can be drawn about changes in human land use? By incorporating a regional altitudinal zonation model, direct field observations and GIS analyses of remotely sensed long term data, the present study examines these questions using the example of Huancayo Metropolitano - an emerging Peruvian mountain city of 420,000 inhabitants, situated at 3260 m asl in the Mantaro Valley. The study's results indicate that rapid urban growth during the late 1980s and early 1990s was followed by the agricultural intensification and peri-urban condominization at the valley floor ( quechua ) - since the beginning of Peru's neoliberal era. Moreover, regarding the adjoining steep slopes ( suni ) and subsequent grassland ecosystems ( puna ), the research output presents land cover change trajectories that clearly show an expansion of human land use, such as reforestation for wood production and range burning for livestock grazing, even at high altitudes - despite rural-urban migration trends and contrary to several results of extra-Andean studies. Consequently, rural-urban planners and policy makers are challenged to focus on the manifold impacts of globalization on human land use - at all altitudinal belts of the Andean city's hinterland: toward sustainable mountain development that bridges the social and physical gaps - from the bottom up.

Mitochondrial DNA Markers Reveal High Genetic Diversity but Low Genetic Differentiation in the Black Fly Simulium tani Takaoka & Davies along an Elevational Gradient in Malaysia

PubMed Central

Low, Van Lun; Adler, Peter H.; Takaoka, Hiroyuki; Ya’cob, Zubaidah; Lim, Phaik Eem; Tan, Tiong Kai; Lim, Yvonne A. L.; Chen, Chee Dhang; Norma-Rashid, Yusoff; Sofian-Azirun, Mohd

2014-01-01

The population genetic structure of Simulium tani was inferred from mitochondria-encoded sequences of cytochrome c oxidase subunits I (COI) and II (COII) along an elevational gradient in Cameron Highlands, Malaysia. A statistical parsimony network of 71 individuals revealed 71 haplotypes in the COI gene and 43 haplotypes in the COII gene; the concatenated sequences of the COI and COII genes revealed 71 haplotypes. High levels of genetic diversity but low levels of genetic differentiation were observed among populations of S. tani at five elevations. The degree of genetic diversity, however, was not in accordance with an altitudinal gradient, and a Mantel test indicated that elevation did not have a limiting effect on gene flow. No ancestral haplotype of S. tani was found among the populations. Pupae with unique structural characters at the highest elevation showed a tendency to form their own haplotype cluster, as revealed by the COII gene. Tajima’s D, Fu’s Fs, and mismatch distribution tests revealed population expansion of S. tani in Cameron Highlands. A strong correlation was found between nucleotide diversity and the levels of dissolved oxygen in the streams where S. tani was collected. PMID:24941043

Diversity and distribution of freshwater testate amoebae (protozoa) along latitudinal and trophic gradients in China.

PubMed

Ju, Lihua; Yang, Jun; Liu, Lemian; Wilkinson, David M

2014-11-01

Freshwater microbial diversity is subject to multiple stressors in the Anthropocene epoch. However, the effects of climate changes and human activities on freshwater protozoa remain poorly understood. In this study, the diversity and distribution of testate amoebae from the surface sediments were investigated in 51 Chinese lakes and reservoirs along two gradients, latitude and trophic status. A total of 169 taxa belonging to 24 genera were identified, and the most diverse and dominant genera were Difflugia (78 taxa), Centropyxis (26 taxa) and Arcella (12 taxa). Our analysis revealed that biomass of testate amoebae decreased significantly along the latitudinal gradient, while Shannon-Wiener indices and species richness presented an opposite trend (P < 0.05). The relationship of diversity and latitude is, we suspect, an artifact of the altitudinal distribution of our sites. Furthermore, biomass-based Shannon-Wiener index and species richness of testate amoebae were significantly unimodally related to trophic status (P < 0.05). This is the first large-scale study showing the effects of latitude and trophic status on diversity and distribution of testate amoebae in China. Therefore, our results provide valuable baseline data on testate amoebae and contribute to lake management and our understanding of the large-scale global patterns in microorganism diversity.

Average niche breadths of species in lake macrophyte communities respond to ecological gradients variably in four regions on two continents.

PubMed

Alahuhta, Janne; Virtala, Antti; Hjort, Jan; Ecke, Frauke; Johnson, Lucinda B; Sass, Laura; Heino, Jani

2017-05-01

Different species' niche breadths in relation to ecological gradients are infrequently examined within the same study and, moreover, species niche breadths have rarely been averaged to account for variation in entire ecological communities. We investigated how average environmental niche breadths (climate, water quality and climate-water quality niches) in aquatic macrophyte communities are related to ecological gradients (latitude, longitude, altitude, species richness and lake area) among four distinct regions (Finland, Sweden and US states of Minnesota and Wisconsin) on two continents. We found that correlations between the three different measures of average niche breadths and ecological gradients varied considerably among the study regions, with average climate and average water quality niche breadth models often showing opposite trends. However, consistent patterns were also found, such as widening of average climate niche breadths and narrowing of average water quality niche breadths of aquatic macrophytes along increasing latitudinal and altitudinal gradients. This result suggests that macrophyte species are generalists in relation to temperature variations at higher latitudes and altitudes, whereas species in southern, lowland lakes are more specialised. In contrast, aquatic macrophytes growing in more southern nutrient-rich lakes were generalists in relation to water quality, while specialist species are adapted to low-productivity conditions and are found in highland lakes. Our results emphasise that species niche breadths should not be studied using only coarse-scale data of species distributions and corresponding environmental conditions, but that investigations on different kinds of niche breadths (e.g., climate vs. local niches) also require finer resolution data at broad spatial extents.

[Altitudinal distribution, richness and composition of bird assemblages in a mountainous region in Southern Nayarit, Mexico].

PubMed

Jaime-Escalante, Nidia Gissell; Figueroa-Esquivel, Elsa Margarita; Villaseñor Gómez, José Fernando; Jacobo-Sapien, Edwin Alberto; Puebla-Olivares, Fernando

2016-12-01

Elevation gradient studies have strengthened the evaluation of changes in richness and composition of bird assemblages. They also provide information on environmental variables that determine bird distribution, and the variables that define their population structure. Our aim was to describe their variation through an elevational cline in Southern Nayarit, Mexico. To analyze the behavior of richness across the gradient, we gathered information through point counts in nine elevational intervals (300 m from each other) from sea level to 2 700 m of elevation. With a standardized sampling effort, we produced rarefaction curves and analyzed changes in species composition by hierarchical classification using the TWINSPAN technique. In order to identify variables associated with richness changes, we examined the effect of precipitation and habitat structure via regression trees. An analysis of nonmetric multidimensional scaling (NMDS) was implemented with the purpose to determine if the changes in composition correspond to changes in vegetation types. Species richness varied significantly across the gradient: high in the lower parts of the gradient, reached its peak in the middle, and decreased monotonically with elevation. Species responded to changes in the cline and were grouped in three elevational zones. Analyses suggest that changes in richness and species composition are influenced by vegetation, its structure and precipitation regime, as well as various aspects related to habitat features and disturbance. These aspects should be taken into account in order to design appropriate strategies for the conservation of the birds of Nayarit.

Genetic evidence for restricted dispersal along continuous altitudinal gradients in a climate change-sensitive mammal: the American Pika.

PubMed

Henry, Philippe; Sim, Zijian; Russello, Michael A

2012-01-01

When faced with rapidly changing environments, wildlife species are left to adapt, disperse or disappear. Consequently, there is value in investigating the connectivity of populations of species inhabiting different environments in order to evaluate dispersal as a potential strategy for persistence in the face of climate change. Here, we begin to investigate the processes that shape genetic variation within American pika populations from the northern periphery of their range, the central Coast Mountains of British Columbia, Canada. At these latitudes, pikas inhabit sharp elevation gradients ranging from sea level to 1500 m, providing an excellent system for studying the effects of local environmental conditions on pika population genetic structure and gene flow. We found low levels of neutral genetic variation compared to previous studies from more southerly latitudes, consistent with the relatively recent post-glacial colonization of the study location. Moreover, significant levels of inbreeding and marked genetic structure were detected within and among sites. Although low levels of recent gene flow were revealed among elevations within a transect, potentially admixed individuals and first generation migrants were identified using discriminant analysis of principal components between populations separated by less than five kilometers at the same elevations. There was no evidence for historical population decline, yet there was signal for recent demographic contractions, possibly resulting from environmental stochasticity. Correlative analyses revealed an association between patterns of genetic variation and annual heat-to-moisture ratio, mean annual precipitation, precipitation as snow and mean maximum summer temperature. Changes in climatic regimes forecasted for the region may thus potentially increase the rate of population extirpation by further reducing dispersal between sites. Consequently, American pika may have to rely on local adaptations or phenotypic plasticity in order to survive predicted climate changes, although additional studies are required to investigate the evolutionary potential of this climate change sensitive species.

Body Size Adaptations to Altitudinal Climatic Variation in Neotropical Grasshoppers of the Genus Sphenarium (Orthoptera: Pyrgomorphidae)

PubMed Central

2015-01-01

Altitudinal clines in body size can result from the effects of natural and sexual selection on growth rates and developing times in seasonal environments. Short growing and reproductive seasons constrain the body size that adults can attain and their reproductive success. Little is known about the effects of altitudinal climatic variation on the diversification of Neotropical insects. In central Mexico, in addition to altitude, highly heterogeneous topography generates diverse climates that can occur even at the same latitude. Altitudinal variation and heterogeneous topography open an opportunity to test the relative impact of climatic variation on body size adaptations. In this study, we investigated the relationship between altitudinal climatic variation and body size, and the divergence rates of sexual size dimorphism (SSD) in Neotropical grasshoppers of the genus Sphenarium using a phylogenetic comparative approach. In order to distinguish the relative impact of natural and sexual selection on the diversification of the group, we also tracked the altitudinal distribution of the species and trends of both body size and SSD on the phylogeny of Sphenarium. The correlative evidence suggests no relationship between altitude and body size. However, larger species were associated with places having a warmer winter season in which the temporal window for development and reproduction can be longer. Nonetheless, the largest species were also associated with highly seasonal environments. Moreover, large body size and high levels of SSD have evolved independently several times throughout the history of the group and male body size has experienced a greater evolutionary divergence than females. These lines of evidence suggest that natural selection, associated with seasonality and sexual selection, on maturation time and body size could have enhanced the diversification of this insect group. PMID:26684616

Diversity of Streptomyces spp. in Eastern Himalayan region – computational RNomics approach to phylogeny

PubMed Central

Bhattacharjee, Kaushik; Banerjee, Subhro; Joshi, Santa Ram

2012-01-01

Isolation and characterization of actinomycetes from soil samples from altitudinal gradient of North-East India were investigated for computational RNomics based phylogeny. A total of 52 diverse isolates of Streptomyces from the soil samples were isolated on four different media and from these 6 isolates were selected on the basis of cultural characteristics, microscopic and biochemical studies. Sequencing of 16S rDNA of the selected isolates identified them to belong to six different species of Streptomyces. The molecular morphometric and physico-kinetic analysis of 16S rRNA sequences were performed to predict the diversity of the genus. The computational RNomics study revealed the significance of the structural RNA based phylogenetic analysis in a relatively diverse group of Streptomyces. PMID:22829729

Younger Dryas glaciers in the High Atlas, Morocco

NASA Astrophysics Data System (ADS)

Hughes, Philip; Fink, David

2016-04-01

Twelve cirque glaciers formed during the Younger Dryas on the mountains of Aksoual (3912 m a.s.l.) and Adrar el Hajj (3129 m a.s.l.) in the Marrakesh High Atlas. Moraines in two separate cirques on these mountains have been dated using 10Be and 36Cl exposure dating. In both cirques the age scatter is relatively small (13.8-10.1 ka) and all ages overlap within error with the Younger Dryas (12.9-11.7 ka). The glaciers were small and covered <2 km2 and formed on north-facing slopes. However, the altitudinal range of the glaciers was very large, with equilibrium line altitudes (ELAs) ranging from 2470 and 3560 m. This large range is attributed to local topoclimatic factors with the lowest glacier (confirmed as Younger Dryas in age by 3 exposure ages) occupying a very steep cirque floor where a combination of steep glacier gradient and a large potential avalanche catchment enabled its low-lying position. This indicates that caution should be taken when using single glacier sites for reconstructing regional palaeoclimate, especially those formed in steep catchments that have strong topoclimatic controls. The average ELA of the twelve Younger Dryas glaciers was c. 3109 m a.s.l. (St Dev = 325 m) and this represents an ELA depression of > 1000 m from the modern theoretical regional ELA. Under precipitation values similar to today this would require a mean annual temperature depression of 9°C. Moreover, the glacier-climate modelling indicates that it is very unlikely that climate was drier than today during the Younger Dryas in the Marrakesh High Atlas.

Vivid valleys, pallid peaks? Hypsometric variations and rural–urban land change in the Central Peruvian Andes

PubMed Central

Haller, Andreas

2012-01-01

What happens to the land cover within the hinterland's altitudinal belts while Central Andean cities are undergoing globalization and urban restructuring? What conclusions can be drawn about changes in human land use? By incorporating a regional altitudinal zonation model, direct field observations and GIS analyses of remotely sensed long term data, the present study examines these questions using the example of Huancayo Metropolitano – an emerging Peruvian mountain city of 420,000 inhabitants, situated at 3260 m asl in the Mantaro Valley. The study's results indicate that rapid urban growth during the late 1980s and early 1990s was followed by the agricultural intensification and peri-urban condominization at the valley floor (quechua) – since the beginning of Peru's neoliberal era. Moreover, regarding the adjoining steep slopes (suni) and subsequent grassland ecosystems (puna), the research output presents land cover change trajectories that clearly show an expansion of human land use, such as reforestation for wood production and range burning for livestock grazing, even at high altitudes – despite rural–urban migration trends and contrary to several results of extra-Andean studies. Consequently, rural–urban planners and policy makers are challenged to focus on the manifold impacts of globalization on human land use – at all altitudinal belts of the Andean city's hinterland: toward sustainable mountain development that bridges the social and physical gaps – from the bottom up. PMID:23564987

Temporal coherence of two alpine lake basins of the Colorado Front Range, USA

USGS Publications Warehouse

Baron, Jill S.; Caine, N.

2000-01-01

1. Knowledge of synchrony in trends is important to determining regional responses of lakes to disturbances such as atmospheric deposition and climate change. We explored the temporal coherence of physical and chemical characteristics of two series of mostly alpine lakes in nearby basins of the Colorado Rocky Mountains. Using year-to-year variation over a 10-year period, we asked whether lakes more similar in exposure to the atmosphere be-haved more similarly than those with greater influence of catchment or in-lake processes.2. The Green Lakes Valley and Loch Vale Watershed are steeply incised basins with strong altitudinal gradients. There are glaciers at the heads of each catchment. The eight lakes studied are small, shallow and typically ice-covered for more than half the year. Snowmelt is the dominant hydrological event each year, flushing about 70% of the annual discharge from each lake between April and mid-July. The lakes do not thermally stratify during the period of open water. Data from these lakes included surface water temper-ature, sulphate, nitrate, calcium, silica, bicarbonate alkalinity and conductivity.3. Coherence was estimated by Pearson's correlation coefficient between lake pairs for each of the different variables. Despite close geographical proximity, there was not a strong direct signal from climatic or atmospheric conditions across all lakes in the study. Individual lake characteristics overwhelmed regional responses. Temporal coherence was higher for lakes within each basin than between basins and was highest for nearest neighbours.4. Among the Green Lakes, conductivity, alkalinity and temperature were temporally coherent, suggesting that these lakes were sensitive to climate fluctuations. Water tem-perature is indicative of air temperature, and conductivity and alkalinity concentrations are indicative of dilution from the amount of precipitation flushed through by snowmelt.5. In Loch Vale, calcium, conductivity, nitrate, sulphate and alkalinity were temporally coherent, while silica and temperature were not. This suggests that external influences are attenuated by internal catchment and lake processes in Loch Vale lakes. Calcium and sulphate are primarily weathering products, but sulphate derives both from deposition and from mineral weathering. Different proportions of snowmelt versus groundwater in different years could influence summer lake concentrations. Nitrate is elevated in lake waters from atmospheric deposition, but the internal dynamics of nitrate and silica may be controlled by lake food webs. Temperature is attenuated by inconsistently different climates across altitude and glacial meltwaters.6. It appears that, while the lakes in the two basins are topographically close, geologically and morphologically similar, and often connected by streams, only some attributes are temporally coherent. Catchment and in-lake processes influenced temporal patterns, especially for temperature, alkalinity and silica. Montane lakes with high altitudinal gradients may be particularly prone to local controls compared to systems where coherence is more obvious.

Modelling Vulnerability and Range Shifts in Ant Communities Responding to Future Global Warming in Temperate Forests.

PubMed

Kwon, Tae-Sung; Li, Fengqing; Kim, Sung-Soo; Chun, Jung Hwa; Park, Young-Seuk

2016-01-01

Global warming is likely leading to species' distributional shifts, resulting in changes in local community compositions and diversity patterns. In this study, we applied species distribution models to evaluate the potential impacts of temperature increase on ant communities in Korean temperate forests, by testing hypotheses that 1) the risk of extinction of forest ant species would increase over time, and 2) the changes in species distribution ranges could drive upward movements of ant communities and further alter patterns of species richness. We sampled ant communities at 335 evenly distributed sites across South Korea and modelled the future distribution range for each species using generalized additive models. To account for spatial autocorrelation, autocovariate regressions were conducted prior to generalized additive models. Among 29 common ant species, 12 species were estimated to shrink their suitable geographic areas, whereas five species would benefit from future global warming. Species richness was highest at low altitudes in the current period, and it was projected to be highest at the mid-altitudes in the 2080s, resulting in an upward movement of 4.9 m yr-1. This altered the altitudinal pattern of species richness from a monotonic-decrease curve (common in temperate regions) to a bell-shaped curve (common in tropical regions). Overall, ant communities in temperate forests are vulnerable to the on-going global warming and their altitudinal movements are similar to other faunal communities.

Diversity of bees and their floral resources at altitudinal areas in the Southern Espinhaço Range, Minas Gerais, Brazil.

PubMed

Araújo, Vinícius A; Antonini, Yasmine; Araújo, Ana P A

2006-01-01

The Southern Espinhaço Range consists of large areas covered by quartzitic or metaliferous tropical altitudinal fields. The Espinhaço Range ecosystems are endangered by anthropic high impacts, particularly due to mining and urbanization. We conducted a one-year inventory of the bee flora and fauna at the quartzitic Ouro Branco Mountains and a two-year survey of the metaliferous Ouro Preto fields. The samples were collected twice a month, from 8:00 am to 5:00 pm. The bees (677) belonged to 91 species, five families. The family Apidae was the richest and most abundant, followed by the Halictidae and Megachilidae. The bees visited 46 flowering plant species; the most visited plants were the Asteraceae (n = 220), the Malpighiaceae (n = 95), the Melastomataceae (n = 94), the Fabaceae (n = 78), and the Solanaceae (n = 63). Diversity was higher in Ouro Branco (H = 1.47) than in Ouro Preto (H = 1.17). The low richness and abundance of bees in our research site when compared to other Brazilian "Cerrado" areas can be due to the high altitude, low temperature, and low availability of flowers we found. "Canga" and rupestrian areas house fauna and flora species that are rare and threatened by extinction. The southern Espinhaço areas can, therefore, be given the status of permanent biodiversity preservation area.

Variation of mobile carbon reserves in trees at the alpine treeline ecotone is under environmental control.

PubMed

Fajardo, Alex; Piper, Frida I; Pfund, Laura; Körner, Christian; Hoch, Günter

2012-09-01

In low temperature-adapted plants, including treeline trees, light-saturated photosynthesis is considerably less sensitive to temperature than growth. As a consequence, all plants tested so far show increased nonstructural carbohydrate (NSC) tissue concentrations when exposed to low temperatures. Reduced carbon supply is thus an unlikely cause for low temperature range limits of plants. For altitudinal treeline trees there is, however, a possibility that high NSC genotypes have been selected. Here, we explored this possibility using afforestations with single-provenance conifers along elevational gradients in the Southern Chilean Andes and the Swiss Alps. Tree growth was measured at each of four approximately equidistant elevations at and below the treeline. Additionally, at the same elevations, needle, branch and stem sapwood tissues were collected to determine NSC concentrations. Overall, growth decreased and NSC concentrations increased with elevation. Along with previous empirical and experimental studies, the findings of this study provide no indication of NSC reduction at the treeline; NSC increased in most species (each represented by one common population) towards their upper climatic limit. The disparity between carbon acquisition and structural carbon investment at low temperature (accumulation of NSC) thus does occur even among genotypes not adapted to treeline environments. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

Photosynthetic temperature adaptation of Pinus cembra within the timberline ecotone of the Central Austrian Alps.

PubMed

Wieser, Gerhard; Oberhuber, Walter; Walder, Lisa; Spieler, Daniela; Gruber, Andreas

2010-04-01

Temperature is suggested to determine the upper limit of tree life. Therefore, future climate warming may be of importance for tree distribution within the European Alps, where low temperatures limit carbon metabolism.We focused on the effects of air and soil temperature on net photosynthesis (P(n)) of Pinus cembra an evergreen climax species of the timberline ecotone of the Central Austrian Alps. Light response and temperature response curves were estimated along an altitudinal gradient ranging from the forest limit up to the krummholz limit in both summer and fall.In general, P(n) was significantly lower in fall as compared to summer. Nevertheless, independent from season mean P(n) values tended to increase with elevation and were positively correlated with root zone temperatures. The specific leaf area by contrast declined with increasing elevation. Furthermore, the temperature optimum of net photosynthesis declined with increasing elevation and was positively correlated with the mean maximum air temperature of the 10 days prior the date of measurement.Thus, our findings appear to reflect a long-term adaptation of the photosynthetic apparatus of Pinus cembra to the general temperature conditions with respect to elevation combined with a short term acclimation to the prevailing temperature regime.

Does testis weight decline towards the Subarctic? A case study on the common frog, Rana temporaria

NASA Astrophysics Data System (ADS)

Hettyey, Attila; Laurila, Anssi; Herczeg, Gábor; Jönsson, K. Ingemar; Kovács, Tibor; Merilä, Juha

2005-04-01

Interpopulation comparisons of variation in resource availability and in allocation patterns along altitudinal and latitudinal gradients allow insights into the mechanisms shaping the life history of animals. Patterns of between-population differences in female life history traits have been studied intensively across a wide range of taxa, but similar investigations in males have remained scarce. To study if testis weight—a measure of reproductive investment—varies on a geographical scale in anurans, we focussed on the variation in relative testis weight (RelTW) and asymmetry in 22 populations of the common frog Rana temporaria along a 1,600-km latitudinal transect across the Scandinavian peninsula. We found that RelTW decreased towards the north. Body mass and body length both had independent positive effects on testes mass. We found evidence for directional asymmetry (DA) in testis weight with the right testis being larger than the left. The level of DA in testis weight was not related to latitude, but both body mass and testes mass had independent positive effects on asymmetry. We discuss the northwards decrease in RelTW in terms of a decreased reproductive investment as a possible consequence of harsher environmental conditions, and perhaps also, weaker sexual selection in the north than in the south.

Comparative susceptibility of introduced forest-dwelling mosquitoes in Hawai'i to avian malaria, Plasmodium relictum

USGS Publications Warehouse

Lapointe, D.A.; Goff, M.L.; Atkinson, C.T.

2005-01-01

To identify potential vectors of avian malaria in Hawaiian native forests, the innate susceptibility of Aedes albopictus, Wyeomyia mitchellii, and Culex quinquefasciatus from 3 geographical sites along an altitudinal gradient was evaluated using local isolates of Plasmodium relictum. Mosquitoes were dissected 5-8 and 9-13 days postinfective blood meal and microscopically examined for oocysts and salivary-gland sporozoites. Sporogony was completed in all 3 species, but prevalence between species varied significantly. Oocysts were detected in 1-2% and sporozoites in 1-7% of Aedes albopictus that fed on infected ducklings. Wyeomyia mitchellii was slightly more susceptible, with 7-19% and 7% infected with oocysts and sporozoites, respectively. In both species, the median oocyst number was 5 or below. This is only the second Wyeomyia species reported to support development of a malarial parasite. Conversely, Culex quinquefasciatus from all 3 sites proved very susceptible. Prevalence of oocysts and sporozoites consistently exceeded 70%, regardless of gametocytemia or origin of the P. relictum isolate. In trials for which a maximum 200 oocysts were recorded, the median number of oocysts ranged from 144 to 200. It was concluded that Culex quinquefasciatus is the primary vector of avian malaria in Hawai'i. ?? American Society of Parasitologists 2005.

Molecular evidence of hybrid zones of Cedrela (Meliaceae) in the Yungas of Northwestern Argentina.

PubMed

Zelener, Noga; Tosto, Daniela; de Oliveira, Luiz Orlando; Soldati, María Cristina; Inza, María Virginia; Fornes, Luis Fernando

2016-09-01

In the Yungas of Northwestern Argentina, three endangered species of Cedrela (C. angustifolia, C. saltensis, and C. balansae) follow altitudinal gradients of distribution with contact zones between them. We sampled 210 individuals from 20 populations that spanned most of Cedrela's geographical range in the Yungas, and used Amplified Fragment Length Polymorphism (AFLP) markers and DNA sequences of the nuclear Internal Transcribed Spacer (ITS) to investigate hybrid zones. Data analyses employed an array of complementary methods, including principal coordinate analyses, Bayesian clustering analyses, maximum likelihood tree-building, and network techniques. Both nuclear molecular systems - AFLP and ITS - provided insights into the evolutionary history of Cedrela in the Yungas in a congruent manner. We uncovered strong support for the occurrence of natural hybridization between C. balansae and C. saltensis. Additionally, we identified hybrid zones in areas of sympatry (at both the Calilegua National Park and the San Andrés farm) and in transition zones from 820 to 1100meters above sea level (localities of Pintascayo and Acambuco). There was no evidence for hybridization of either C. balansae or C. saltensis with C. angustifolia. The role of hybrid populations in conservation and use of genetic resources in the Yungas were discussed. Copyright © 2016 Elsevier Inc. All rights reserved.

Anastrepha ludens and Anastrepha serpentina (Diptera: Tephritidae) do not infest Psidium guajava (Myrtaceae), but Anastrepha obliqua occasionally shares this resource with Anastrepha striata in nature.

PubMed

Birke, Andrea; Aluja, Martin

2011-08-01

This study examined whether economically important fruit fly species Anastrepha ludens (Loew), Anastrepha serpentina (Wiedemann), and Anastrepha obliqua (Macquart) (Diptera: Tephritidae) may opportunistically exploit guavas, Psidium guajava L. (Myrtaceae), growing near preferred natural hosts. We collected 3,459 kg of guavas and 895 kg of other known host species [sour orange, Citrus aurantium L.; grapefruit, Citrus paradisi Macfadyen; mango, Mangifera indica L.; white sapote, Casimiroa edulis La Llave and Lex.; sapote, Pouteria sapota (Jacq.); sapodilla, Manilkara zapota L.; and wild plum, Spondias purpurea L. and Spondias mombin L.] along an altitudinal gradient over a 4-yr period (2006-2009). Plants were growing in sympatry in 23 localities where the guavas are usually infested in the state of Veracruz, M6xico. The guava samples yielded 20,341 Anastrepha spp. pupae in total (overall mean, 5.88 pupae per kg of fruit). Confirming previous reports, Anastrepha fraterculus (Wiedemann) and Anastrepha striata (Schiner) were found heavily infesting guavas in Veracruz. Importantly, although we did not find evidence that A. ludens and A. serpentina are able to attack this valuable commodity, we document for the first time in the agriculturally important state of Veracruz that P. guajava is an alternative natural host plant of A. obliqua. We recovered two fruit in the mango-growing locality of la Vibora, Tlalixcoyan, that harbored larvae of A. striata and A. obliqua. This finding has important practical implications for management of A. obliqua. Over the entire altitudinal gradient, when individual fruit infestation was examined, a dynamic pattern of species dominance was unveiled with guavas growing below 800 m above sea level mainly attacked by A. striata and a progressive replacement with increasing altitude by A. fraterculus. Interestingly, most individual fruit examined (97%) harbored a single species of fruit fly, a finding that may be taken as evidence of competitive displacement among sympatric species of fruit flies. Based on this study and previously published work by us on this topic, we conclude that literature reports indicating that A. ludens and A. serpentina infest guavas under field conditions should be questioned.

Elevation Pattern in Growth Coherency on the Southeastern Tibetan Plateau

PubMed Central

Lyu, Lixin; Deng, Xu; Zhang, Qi-Bin

2016-01-01

It is generally expected that inter-annual changes in radial growth among trees would be similar to the increase in altitude due to the limitation of increasingly harsher climatic factors. Here, we examine whether this pattern exists in alpine forests on the southeastern Tibetan Plateau. Increment cores were collected from mature trees at the lower, middle and upper limits of balfour spruce (Picea likiangensis var. balfouriana (Rehd. et Wils.) Hillier ex Slsvin) forests at the Buze and Yela Mountains in Basu County, Changdu Prefecture of Tibet, China. The treeline elevations are 4320 m and 4510 m a.s.l. for Buze and Yela, respectively. Tree-ring widths were measured, crossdated, and detrended to obtain a sequence of ring-width indices for each individual sample. Annual growth rate, climate sensitivity, growth-climate relationships, and growth synchrony among trees were calculated and compared across altitudes. In Buze Mountain, the annual growth rate of trees has no significant difference across altitudes. The mean sensitivity of trees is lower at the treelines than at lower elevations. Tree growth has stronger correlation with winter temperature at upper elevations than at lower elevations, has significant correlation with moisture, not temperature, in the growing season, and the growth response to moisture is lower at the treeline than at lower elevations. The correlation among individual tree-ring sequences is lower at the treeline than at sites at lower elevation. In Yela Mountain, the characterisitics of annual growth rate, mean sensitivity, tree growth-climate relationships, and inter-serial correlation are similar to those in Buze, but their differences along altitudinal gradients are less significant as those in Buze. Our data do not support the general expectation of growth convergence among individuals with increasing altitude. We conclude that individual heterogeneity and microhabitat diversity are important features for treeline trees that may dampen the growth synchrony in trees. The results obtained in this study expand our knowledge about the pattern of forest growth along altitudinal gradients in high-elevation regions and demonstrate the importance of checking the growth of tree individuals before analyzing the average signal. PMID:27685668

Elevation Pattern in Growth Coherency on the Southeastern Tibetan Plateau.

PubMed

Lyu, Lixin; Deng, Xu; Zhang, Qi-Bin

It is generally expected that inter-annual changes in radial growth among trees would be similar to the increase in altitude due to the limitation of increasingly harsher climatic factors. Here, we examine whether this pattern exists in alpine forests on the southeastern Tibetan Plateau. Increment cores were collected from mature trees at the lower, middle and upper limits of balfour spruce (Picea likiangensis var. balfouriana (Rehd. et Wils.) Hillier ex Slsvin) forests at the Buze and Yela Mountains in Basu County, Changdu Prefecture of Tibet, China. The treeline elevations are 4320 m and 4510 m a.s.l. for Buze and Yela, respectively. Tree-ring widths were measured, crossdated, and detrended to obtain a sequence of ring-width indices for each individual sample. Annual growth rate, climate sensitivity, growth-climate relationships, and growth synchrony among trees were calculated and compared across altitudes. In Buze Mountain, the annual growth rate of trees has no significant difference across altitudes. The mean sensitivity of trees is lower at the treelines than at lower elevations. Tree growth has stronger correlation with winter temperature at upper elevations than at lower elevations, has significant correlation with moisture, not temperature, in the growing season, and the growth response to moisture is lower at the treeline than at lower elevations. The correlation among individual tree-ring sequences is lower at the treeline than at sites at lower elevation. In Yela Mountain, the characterisitics of annual growth rate, mean sensitivity, tree growth-climate relationships, and inter-serial correlation are similar to those in Buze, but their differences along altitudinal gradients are less significant as those in Buze. Our data do not support the general expectation of growth convergence among individuals with increasing altitude. We conclude that individual heterogeneity and microhabitat diversity are important features for treeline trees that may dampen the growth synchrony in trees. The results obtained in this study expand our knowledge about the pattern of forest growth along altitudinal gradients in high-elevation regions and demonstrate the importance of checking the growth of tree individuals before analyzing the average signal.

Temperature-dependent phenology of Plutella xylostella (Lepidoptera: Plutellidae): Simulation and visualization of current and future distributions along the Eastern Afromontane.

PubMed

Ngowi, Benignus V; Tonnang, Henri E Z; Mwangi, Evans M; Johansson, Tino; Ambale, Janet; Ndegwa, Paul N; Subramanian, Sevgan

2017-01-01

There is a scarcity of laboratory and field-based results showing the movement of the diamondback moth (DBM) Plutella xylostella (L.) across a spatial scale. We studied the population growth of the diamondback moth (DBM) Plutella xylostella (L.) under six constant temperatures, to understand and predict population changes along altitudinal gradients and under climate change scenarios. Non-linear functions were fitted to continuously model DBM development, mortality, longevity and oviposition. We compiled the best-fitted functions for each life stage to yield a phenology model, which we stochastically simulated to estimate the life table parameters. Three temperature-dependent indices (establishment, generation and activity) were derived from a logistic population growth model and then coupled to collected current (2013) and downscaled temperature data from AFRICLIM (2055) for geospatial mapping. To measure and predict the impacts of temperature change on the pest's biology, we mapped the indices along the altitudinal gradients of Mt. Kilimanjaro (Tanzania) and Taita Hills (Kenya) and assessed the differences between 2013 and 2055 climate scenarios. The optimal temperatures for development of DBM were 32.5, 33.5 and 33°C for eggs, larvae and pupae, respectively. Mortality rates increased due to extreme temperatures to 53.3, 70.0 and 52.4% for egg, larvae and pupae, respectively. The net reproduction rate reached a peak of 87.4 female offspring/female/generation at 20°C. Spatial simulations indicated that survival and establishment of DBM increased with a decrease in temperature, from low to high altitude. However, we observed a higher number of DBM generations at low altitude. The model predicted DBM population growth reduction in the low and medium altitudes by 2055. At higher altitude, it predicted an increase in the level of suitability for establishment with a decrease in the number of generations per year. If climate change occurs as per the selected scenario, DBM infestation may reduce in the selected region. The study highlights the need to validate these predictions with other interacting factors such as cropping practices, host plants and natural enemies.

Diversity patterns of selected Andean plant groups correspond to topography and habitat dynamics, not orogeny

PubMed Central

Mutke, Jens; Jacobs, Rana; Meyers, Katharina; Henning, Tilo; Weigend, Maximilian

2014-01-01

The tropical Andes are a hotspot of biodiversity, but detailed altitudinal and latitudinal distribution patterns of species are poorly understood. We compare the distribution and diversity patterns of four Andean plant groups on the basis of georeferenced specimen data: the genus Nasa (Loasaceae), the two South American sections of Ribes (sect. Parilla and sect. Andina, Grossulariaceae), and the American clade of Urtica (Urticaceae). In the tropical Andes, these often grow together, especially in (naturally or anthropogenically) disturbed or secondary vegetation at middle to upper elevations. The climatic niches of the tropical groups studied here are relatively similar in temperature and temperature seasonality, but do differ in moisture seasonality. The Amotape–Huancabamba Zone (AHZ) between 3 and 8° S shows a clear diversity peak of overall species richness as well as for narrowly endemic species across the groups studied. For Nasa, we also show a particular diversity of growth forms in the AHZ. This can be interpreted as proxy for a high diversity of ecological niches based on high spatial habitat heterogeneity in this zone. Latitudinal ranges are generally larger toward the margins of overall range of the group. Species number and number of endemic species of our taxa peak at elevations of 2,500–3,500 m in the tropical Andes. Altitudinal diversity patterns correspond well with the altitudinal distribution of slope inclination. We hypothesize that the likelihood and frequency of landslides at steeper slopes translate into temporal habitat heterogeneity. The frequency of landslides may be causally connected to diversification especially for the numerous early colonizing taxa, such as Urtica and annual species of Nasa. In contrast to earlier hypotheses, uplift history is not reflected in the pattern here retrieved, since the AHZ is the area of the most recent Andean uplift. Similarly, a barrier effect of the low-lying Huancabamba depression is not retrieved in our data. PMID:25346750

Comparative habitat use in a juniper woodland bird community

USGS Publications Warehouse

Pavlacky, D.C.; Anderson, S.H.

2004-01-01

We compared vegetation structure used by 14 bird species during the 1998 and 1999 breeding seasons to determine what habitat features best accounted for habitat division and community organization in Utah juniper (Juniperus osteosperma) woodlands of southwestern Wyoming. Habitat use was quantified by measuring 24 habitat variables in 461 bird-centered quadrats, each 0.04 ha in size. Using discriminant function analysis, we differentiated between habitat used by 14 bird species along 3 habitat dimensions: (1) variation in shrub cover, overstory juniper cover, mature tree density, understory height, and decadent tree density; (2) a gradient composed of elevation and forb cover; and (3) variation in grass cover, tree height, seedling/sapling cover, and bare ground/rock cover. Of 14 species considered, 9 exhibited substantial habitat partitioning: Mourning Dove (Zenaida macroura), Bewick's Wren (Thryomanes bewickii), Blue-gray Gnatcatcher (Polioptila caerulea), Mountain Bluebird (Sialia currucoides), Plumbeous Vireo (Vireo plumbeus), Green-tailed Towhee (Pipilo chlorurus), Brewer's Sparrow (Spizella breweri), Dark-eyed Junco (Junco hyemalis), and Cassin's Finch (Carpodacus cassinii). Our results indicate juniper bird communities of southwestern Wyoming are organized along a 3-dimensional habitat gradient composed of woodland maturity, elevation, and juniper recruitment. Because juniper birds partition habitat along successional and altitudinal gradients, indiscriminate woodland clearing as well as continued fire suppression will alter species composition. Restoration efforts should ensure that all successional stages of juniper woodland are present on the landscape.

Long-term protection effects of National Reserve to forest vegetation in 4 decades: biodiversity change analysis of major forest types in Changbai Mountain Nature Reserve, China.

PubMed

Bai, Fan; Sang, WeiGuo; Li, GuangQi; Liu, RuiGang; Chen, LingZhi; Wang, Kun

2008-10-01

The Changbai Mountain Nature Reserve (CNR) was established in 1960 to protect the virgin Korean pine mixed hardwood forest, a typical temperate forest of northeast China. We conducted systematic studies of vascular diversity patterns on the north slope of the CNR mountainside forests (800-1700 m a.s.l.) in 1963 and 2006 respectively. The aim of this comparison is to assess the long-term effects of the protection on plant biodiversity of CNR during the interval 43 years. The research was carried out in three types of forests: mixed coniferous and broad-leaved forest (MCBF), mixed coniferous forest (MCF), and sub-alpine coniferous forest (SCF), characterized by different dominant species. The alpha diversity indicted by species richness and the Shannon-Wiener index were found different in the same elevations and forest types during the 43-year interval. The floral composition and the diversity of vascular species were generally similar along altitudinal gradients before and after the 43-year interval, but some substantial changes were evident with the altitude gradient. In the tree layers, the dominant species in 2006 were similar to those of 1963, though diversity declined with altitude. The indices in the three forest types did not differ significantly between 1963 and 2006, and these values even increased in the MCBF and MCF from 1963 to 2006. However, originally dominant species, P. koraiensis for example, tended to decline, while the proportion of broad-leaved trees increased, and the species turnover in the succession layers trended to shift to higher altitudes. The diversity pattern of the under canopy fluctuated along the altitudinal gradient due to micro-environmental variations. Comparison of the alpha diversity in the three forests shows that the diversity of the shrub and herb layer decreased with time. During the process of survey, we also found some rare and medicinal species disappeared. Analysis indicates that the changes of the diversity pattern in this region are caused by both nature and human factors. Meteorological records revealed that climate has changed significantly in the past 43 years. We also found the most severe human disturbance to the CNR forests in the process of another field survey that is the exploitation of herb medicines and Korean pine nuts. We hope this research would give some guidance to the future reserve management in Changbai Mountain area.

Natural resilience in Arctic charr Salvelinus alpinus: life history, spatial and dietary alterations along gradients of interspecific interactions.

PubMed

Hammar, J

2014-07-01

The Arctic charr Salvelinus alpinus species complex has been shown to be exceptionally vulnerable to rapid abiotic and biotic changes. Salvelinus alpinus, however, inhabit environmental extremes ranging from lakes and rivers in the High Arctic to deep multi-fish species lakes far outside the polar region. Long-term responses to post-glacial environmental variations and successively increased interspecific interactions reveal an essential degree of natural ecological resilience and phenotypic flexibility. Case studies in Scandinavia and Newfoundland illustrate the alternate trophic roles of S. alpinus, and its flexible niche use and life-history changes in order to regain or maintain body size in gradients of lakes with increasing fish species diversity. While allopatric in northern low-productive upland lakes, landlocked populations are commonly structured by cannibalism. In sympatry with other fish species, S. alpinus mostly serve as prey, with their decreasing growth and body size reflecting the successive diet shift from littoral macro-benthos to zooplankton and profundal microbenthos as interspecific competition for food and habitat intensifies. Interactions with natural and introduced superior zooplankton feeders and ultimate predators finally become detrimental. Consequently, the niche of S. alpinus is increasingly compressed in lakes along latitudinal and altitudinal gradients, although certain natural key conditions offer S. alpinus temporary asylum in the inescapable process towards local and regional extinction. The water temperature drop during winter allows S. alpinus to temporarily resume the richer littoral dietary and spatial niche use in low diversity lakes. In southern lowland and coastal lakes with more complex fish communities, access to key prey species such as profundal macro-crustaceans and smelt Osmerus spp. allow S. alpinus to regain its original niche space and characteristics as a large piscivore. In conclusion, S. alpinus along its evolutionary landscape demonstrates associated alterations of life-history characteristics, such as body size and longevity, and thus reproductive traits demonstrating similarities between northern cannibals and southern piscivores. Although including a high degree of natural resilience, obviously differing among S. alpinus populations along its range, differences seen in extreme marginal populations may have been adaptive and the product of an evolutionary response with optimized growth resulting from natural selection due to ultimate intra or inter-specific competition and predation. © 2014 The Fisheries Society of the British Isles.

Indicative capacity of NDVI in predictive mapping of the properties of plow horizons of soils on slopes in the south of Western Siberia

NASA Astrophysics Data System (ADS)

Gopp, N. V.; Nechaeva, T. V.; Savenkov, O. A.; Smirnova, N. V.; Smirnov, V. V.

2017-11-01

The informativeness of NDVI for predictive mapping of the physical and chemical properties of plow horizons of soils on different slope positions within the first (280-310 m a.s.l.) and second (240-280 m a.s.l.) altitudinal steps has been examined. This index is uninformative for mapping soil properties in small hollows, whose factual width is less than the Landsat image resolution (30 m). In regression models, NDVI index explains 52% of variance in the content of humus; 35 and 24% of variance in the contents of total and nitrate nitrogen; 19 and 29% of variance in the contents of total and available phosphorus; 25 and 50% of variance in the contents of exchangeable calcium and manganese; and 30 and 29% of variance in the contents of fine silt and soil water, respectively. On the basis of the models obtained, prognostic maps of the soil properties have been developed. Spatial distribution patterns of NDVI calculated from Landsat 8 images (30-m resolution) serve as the cartographic base and the main indicator of the soil properties. The NDVI values and the contents of humus, physical clay (<0.01 mm) and fine silt particles, total and nitrate nitrogen, total phosphorus, and exchangeable calcium and manganese in the soils of the first altitudinal step are higher than those in the soils of the second altitudinal step. An opposite tendency has been found for the available phosphorus content: in the soils of the second altitudinal step and the hollow, its content is higher than that in the soils of the first altitudinal step by 1.8 and 2.4 times, respectively. Differences in the pH of soil water suspensions, easily available phosphorus, and clay in the soils of the compared topographic positions (first and second altitudinal steps and the hollow) are statistically unreliable.

Body proportions in ancient Andeans from high and low altitudes.

PubMed

Weinstein, Karen J

2005-11-01

Living human populations from high altitudes in the Andes exhibit relatively short limbs compared with neighboring groups from lower elevations as adaptations to cold climates characteristic of high-altitude environments. This study compares relative limb lengths and proportions in pre-Contact human skeletons from different altitudes to test whether ecogeographic variation also existed in Andean prehistory. Maximum lengths of the humerus, radius, femur, and tibia, and femoral head breadth are measured in sex-specific groups of adult human skeletons (N = 346) from the central (n = 80) and the south-central (n = 123) Andean coasts, the Atacama Desert at 2,500 m (n = 102), and the southern Peruvian highlands at 2,000-3,800 m (n = 41). To test whether limb lengths vary with altitude, comparisons are made of intralimb proportions, limb lengths against body mass estimates derived from published equations, limb lengths against the geometric mean of all measurements, and principal component analysis. Intralimb proportions do not statistically differ between coastal groups and those from the Atacama Desert, whereas intralimb proportions are significantly shorter in the Peruvian highland sample. Overall body size and limb lengths relative to body size vary along an altitudinal gradient, with larger individuals from coastal environments and smaller individuals with relatively longer limbs for their size from higher elevations. Ecogeographic variation in relation to climate explains the variation in intralimb proportions, and dietary variation may explain the altitudinal cline in body size and limb lengths relative to body size. The potential effects of gene flow on variation in body proportions in Andean prehistory are also explored. Copyright 2005 Wiley-Liss, Inc

Climate change is affecting altitudinal migrants and hibernating species.

PubMed

Inouye, D W; Barr, B; Armitage, K B; Inouye, B D

2000-02-15

Calendar date of the beginning of the growing season at high altitude in the Colorado Rocky Mountains is variable but has not changed significantly over the past 25 years. This result differs from growing evidence from low altitudes that climate change is resulting in a longer growing season, earlier migrations, and earlier reproduction in a variety of taxa. At our study site, the beginning of the growing season is controlled by melting of the previous winter's snowpack. Despite a trend for warmer spring temperatures the average date of snowmelt has not changed, perhaps because of the trend for increased winter precipitation. This disjunction between phenology at low and high altitudes may create problems for species, such as many birds, that migrate over altitudinal gradients. We present data indicating that this already may be true for American robins, which are arriving 14 days earlier than they did in 1981; the interval between arrival date and the first date of bare ground has grown by 18 days. We also report evidence for an effect of climate change on hibernation behavior; yellow-bellied marmots are emerging 38 days earlier than 23 years ago, apparently in response to warmer spring air temperatures. Migrants and hibernators may experience problems as a consequence of these changes in phenology, which may be exacerbated if climate models are correct in their predictions of increased winter snowfall in our study area. The trends we report for earlier formation of permanent snowpack and for a longer period of snow cover also have implications for hibernating species.

Climate change is affecting altitudinal migrants and hibernating species

PubMed Central

Inouye, David W.; Barr, Billy; Armitage, Kenneth B.; Inouye, Brian D.

2000-01-01

Calendar date of the beginning of the growing season at high altitude in the Colorado Rocky Mountains is variable but has not changed significantly over the past 25 years. This result differs from growing evidence from low altitudes that climate change is resulting in a longer growing season, earlier migrations, and earlier reproduction in a variety of taxa. At our study site, the beginning of the growing season is controlled by melting of the previous winter's snowpack. Despite a trend for warmer spring temperatures the average date of snowmelt has not changed, perhaps because of the trend for increased winter precipitation. This disjunction between phenology at low and high altitudes may create problems for species, such as many birds, that migrate over altitudinal gradients. We present data indicating that this already may be true for American robins, which are arriving 14 days earlier than they did in 1981; the interval between arrival date and the first date of bare ground has grown by 18 days. We also report evidence for an effect of climate change on hibernation behavior; yellow-bellied marmots are emerging 38 days earlier than 23 years ago, apparently in response to warmer spring air temperatures. Migrants and hibernators may experience problems as a consequence of these changes in phenology, which may be exacerbated if climate models are correct in their predictions of increased winter snowfall in our study area. The trends we report for earlier formation of permanent snowpack and for a longer period of snow cover also have implications for hibernating species. PMID:10677510

Altitudinally divergent adult phenotypes in Iberian wall lizards are not driven by egg differences or hatchling growth rates.

PubMed

Ortega, Jesús; López, Pilar; Martín, José

2015-02-01

The interplay between ecological conditions and life histories has been widely acknowledged in vertebrates, particularly in lizards. Environmental conditions may exert different selective pressures and produce divergent phenotypes even in geographically and genetically close populations. The Iberian wall lizard constitutes a perfect model organism as it is considered a species complex with a complicated evolutionary history. Here, we focus on two proximate populations in which we examined adult morphology and reproductive investment of wild-caught lizards along a 500-m altitudinal gradient with contrasting environmental conditions, where adults show marked morphological differences in spite of being closely related. Also, we performed a common garden experiment to examine embryonic and hatchling growth. We focused on reproductive investment per clutch, incubation time, egg size, morphology and growth rate of hatchlings. Results showed clutch size differences between populations that were independent of the larger body size of highland females. However, there were no egg morphological differences between populations, except for egg width, and this difference disappeared after controlling for female body size. Hatchling lizards from both populations did not differ in morphology. Moreover, we did not observe differences between populations or sexes in hatchling growth. Overall, we provide evidence that the differences in adult body size and clutch size are not driven by size at hatching which is not contributed to by egg size, nor are intrinsic hatchling growth rates associated with the environmental conditions experienced in our common garden experiment, suggesting that adult phenotypes are not the result of intrinsic differences between populations.

Changes in intestinal microbiota across an altitudinal gradient in the lizard Phrynocephalus vlangalii.

PubMed

Zhang, Wenya; Li, Na; Tang, Xiaolong; Liu, Naifa; Zhao, Wei

2018-05-01

High altitude is an important driving force in animal evolution. However, the effect of altitude on gut microbial communities in reptiles has not been examined in detail. Here, we investigated the intestinal microbiota of three populations of the lizard Phrynocephalus vlangalii living at different altitudes using 16S rRNA gene sequencing. Bacteroidetes, Firmicutes, and Proteobacteria were the most abundant phyla. Bacteroides , Odoribacter , and Parabacteroides were the most abundant genera. Significant differences in the intestinal microbiota composition were found among the three populations from different altitudes. The proportions of Verrucomicrobia and Akkermansia decreased, whereas Bacteroides increased significantly with altitude. Greater abundance of Bacteroides at higher altitude led to the fractional increase in the phylum Bacteroides relative to other phyla. Hypoxia may be the main factor that caused intestinal microbiota variation in P. vlangalii along the altitude gradient. Overall, our study suggested that the community composition and structure of intestinal microbiota of the lizard P. vlangalii varied along altitudes, and such differences likely play a certain role in highland adaptation. Our findings warrant a further study that would determine whether ambient and body temperatures play a key role in the modulation of intestinal microbiota in reptiles.

Factors controlling soil organic carbon stability along a temperate forest altitudinal gradient

PubMed Central

Tian, Qiuxiang; He, Hongbo; Cheng, Weixin; Bai, Zhen; Wang, Yang; Zhang, Xudong

2016-01-01

Changes in soil organic carbon (SOC) stability may alter carbon release from the soil and, consequently, atmospheric CO2 concentration. The mean annual temperature (MAT) can change the soil physico-chemical characteristics and alter the quality and quantity of litter input into the soil that regulate SOC stability. However, the relationship between climate and SOC stability remains unclear. A 500-day incubation experiment was carried out on soils from an 11 °C-gradient mountainous system on Changbai Mountain in northeast China. Soil respiration during the incubation fitted well to a three-pool (labile, intermediate and stable) SOC decomposition model. A correlation analysis revealed that the MAT only influenced the labile carbon pool size and not the SOC stability. The intermediate carbon pool contributed dominantly to cumulative carbon release. The size of the intermediate pool was strongly related to the percentage of sand particle. The decomposition rate of the intermediate pool was negatively related to soil nitrogen availability. Because both soil texture and nitrogen availability are temperature independent, the stability of SOC was not associated with the MAT, but was heavily influenced by the intrinsic processes of SOC formation and the nutrient status. PMID:26733344

Patterns of fish community composition along a river affected by agricultural and urban disturbance in south-central Chile

DOE Office of Scientific and Technical Information (OSTI.GOV)

Orrego, Rodrigo; Barra, Ricardo; Chiang, Gustavo

2008-03-01

Patterns of fish community composition in a south-central Chile river were investigated along the altitudinal-spatial and environmental gradient and as a function of anthropogenic factors. The spatial pattern of fish communities in different biocoenotic zones of the Chillan River is influenced by both natural factors such a hydrologic features, habitat, and feeding types, and also by water quality variables which can reduce the diversity and abundance of sensitive species. A principal component analysis incorporating both water quality parameters and biomarker responses of representative fish species was used to evaluate the status of fish communities along the spatial gradient of themore » stream. The abundance and diversity of the fish community changed from a low in the upper reaches where the low pollution-tolerant species such as salmonid dominated, to a reduced diversity in the lower reaches of the river where tolerant browser species such as cypriniformes dominated. Even though the spatial pattern of fish community structure is similar to that found for the Chilean Rivers, the structure of these communities is highly influenced by human disturbance, particularly along the lower reaches of the river.« less

Altitudinal variation at 20 years in ponderosa and jeffrey pines

Treesearch

R. Z. Callaham; A. R. Liddicoet

1961-01-01

Early returns from a study of altitudinal variation of pines along an elevational transect in California indicated middle elevation sources grew best regardless of the elevation of planting, seeming to contradict the old maxim, "Local seed source is best" (6). Later returns bring some support for the maxim as local seed sources assert them selves after 20...

Species turnover drives β-diversity patterns across multiple spatial scales of plant-galling interactions in mountaintop grasslands.

PubMed

Coelho, Marcel Serra; Carneiro, Marco Antônio Alves; Branco, Cristina Alves; Borges, Rafael Augusto Xavier; Fernandes, Geraldo Wilson

2018-01-01

This study describes differences in species richness and composition of the assemblages of galling insects and their host plants at different spatial scales. Sampling was conducted along altitudinal gradients composed of campos rupestres and campos de altitude of two mountain complexes in southeastern Brazil: Espinhaço Range and Mantiqueira Range. The following hypotheses were tested: i) local and regional richness of host plants and galling insects are positively correlated; ii) beta diversity is the most important component of regional diversity of host plants and galling insects; and iii) Turnover is the main mechanism driving beta diversity of both host plants and galling insects. Local richness of galling insects and host plants increased with increasing regional richness of species, suggesting a pattern of unsaturated communities. The additive partition of regional richness (γ) into local and beta components shows that local richnesses (α) of species of galling insects and host plants are low relative to regional richness; the beta (β) component incorporates most of the regional richness. The multi-scale analysis of additive partitioning showed similar patterns for galling insects and host plants with the local component (α) incorporated a small part of regional richness. Beta diversity of galling insects and host plants were mainly the result of turnover, with little contribution from nesting. Although the species composition of galling insects and host plant species varied among sample sites, mountains and even mountain ranges, local richness remained relatively low. In this way, the addition of local habitats with different landscapes substantially affects regional richness. Each mountain contributes fundamentally to the composition of regional diversity of galling insects and host plants, and so the design of future conservation strategies should incorporate multiple scales.

Distribution of pines in the Iberian Peninsula agrees with species differences in foliage frost tolerance, not with vulnerability to freezing-induced xylem embolism.

PubMed

Fernández-Pérez, Laura; Villar-Salvador, Pedro; Martínez-Vilalta, Jordi; Toca, Andrei; Zavala, Miguel A

2018-04-01

Drought and frosts are major determinants of plant functioning and distribution. Both stresses can cause xylem embolism and foliage damage. The objective of this study was to analyse if the distribution of six common pine species along latitudinal and altitudinal gradients in Europe is related to their interspecific differences in frost tolerance and to the physiological mechanisms underlying species-specific frost tolerance. We also evaluate if frost tolerance depends on plant water status. We studied survival to a range of freezing temperatures in 2-year-old plants and assessed the percentage loss of hydraulic conductivity (PLC) due xylem embolism formation and foliage damage determined by needle electrolyte leakage (EL) after a single frost cycle to -15 °C and over a range of predawn water potential (ψpd) values. Species experiencing cold winters in their range (Pinus nigra J.F. Arnold, Pinus sylvestris L. and Pinus uncinata Raymond ex A. DC.) had the highest frost survival rates and lowest needle EL and soluble sugar (SS) concentration. In contrast, the pines inhabiting mild or cool winter locations (especially Pinus halepensis Mill. and Pinus pinea L. and, to a lesser extent, Pinus pinaster Ait.) had the lowest frost survival and highest needle EL and SS values. Freezing-induced PLC was very low and differences among species were not related to frost damage. Reduction in ψpd decreased leaf frost damage in P. pinea and P. sylvestris, increased it in P. uncinata and had a neutral effect on the rest of the species. This study demonstrates that freezing temperatures are a major environmental driver for pine distribution and suggests that interspecific differences in leaf frost sensitivity rather than vulnerability to freezing-induced embolism or SS explain pine juvenile frost survival.

Linking seasonal home range size with habitat selection and movement in a mountain ungulate.

PubMed

Viana, Duarte S; Granados, José Enrique; Fandos, Paulino; Pérez, Jesús M; Cano-Manuel, Francisco Javier; Burón, Daniel; Fandos, Guillermo; Aguado, María Ángeles Párraga; Figuerola, Jordi; Soriguer, Ramón C

2018-01-01

Space use by animals is determined by the interplay between movement and the environment, and is thus mediated by habitat selection, biotic interactions and intrinsic factors of moving individuals. These processes ultimately determine home range size, but their relative contributions and dynamic nature remain less explored. We investigated the role of habitat selection, movement unrelated to habitat selection and intrinsic factors related to sex in driving space use and home range size in Iberian ibex, Capra pyrenaica . We used GPS collars to track ibex across the year in two different geographical areas of Sierra Nevada, Spain, and measured habitat variables related to forage and roost availability. By using integrated step selection analysis (iSSA), we show that habitat selection was important to explain space use by ibex. As a consequence, movement was constrained by habitat selection, as observed displacement rate was shorter than expected under null selection. Selection-independent movement, selection strength and resource availability were important drivers of seasonal home range size. Both displacement rate and directional persistence had a positive relationship with home range size while accounting for habitat selection, suggesting that individual characteristics and state may also affect home range size. Ibex living at higher altitudes, where resource availability shows stronger altitudinal gradients across the year, had larger home ranges. Home range size was larger in spring and autumn, when ibex ascend and descend back, and smaller in summer and winter, when resources are more stable. Therefore, home range size decreased with resource availability. Finally, males had larger home ranges than females, which might be explained by differences in body size and reproductive behaviour. Movement, selection strength, resource availability and intrinsic factors related to sex determined home range size of Iberian ibex. Our results highlight the need to integrate and account for process dependencies, here the interdependence of movement and habitat selection, to understand how animals use space. This study contributes to understand how movement links environmental and geographical space use and determines home range behaviour in large herbivores.

Modelling Vulnerability and Range Shifts in Ant Communities Responding to Future Global Warming in Temperate Forests

PubMed Central

Kim, Sung-Soo; Chun, Jung Hwa; Park, Young-Seuk

2016-01-01

Global warming is likely leading to species’ distributional shifts, resulting in changes in local community compositions and diversity patterns. In this study, we applied species distribution models to evaluate the potential impacts of temperature increase on ant communities in Korean temperate forests, by testing hypotheses that 1) the risk of extinction of forest ant species would increase over time, and 2) the changes in species distribution ranges could drive upward movements of ant communities and further alter patterns of species richness. We sampled ant communities at 335 evenly distributed sites across South Korea and modelled the future distribution range for each species using generalized additive models. To account for spatial autocorrelation, autocovariate regressions were conducted prior to generalized additive models. Among 29 common ant species, 12 species were estimated to shrink their suitable geographic areas, whereas five species would benefit from future global warming. Species richness was highest at low altitudes in the current period, and it was projected to be highest at the mid-altitudes in the 2080s, resulting in an upward movement of 4.9 m yr−1. This altered the altitudinal pattern of species richness from a monotonic-decrease curve (common in temperate regions) to a bell-shaped curve (common in tropical regions). Overall, ant communities in temperate forests are vulnerable to the on-going global warming and their altitudinal movements are similar to other faunal communities. PMID:27504632

Reticulate Pleistocene evolution of Ethiopian rodent genus along remarkable altitudinal gradient.

PubMed

Bryja, Josef; Kostin, Danila; Meheretu, Yonas; Šumbera, Radim; Bryjová, Anna; Kasso, Mohammed; Mikula, Ondřej; Lavrenchenko, Leonid A

2018-01-01

The Ethiopian highlands are the most extensive complex of mountainous habitats in Africa. The presence of the Great Rift Valley (GRV) and the striking elevational ecological gradients inhabited by recently radiated Ethiopian endemics, provide a wide spectrum of model situations for evolutionary studies. The extant species of endemic rodents, often markedly phenotypically differentiated, are expected to possess complex genetic features which evolved asa consequence of the interplay between geomorphology and past climatic changes. In this study, we used the largest available multi-locus genetic dataset of the murid genus Stenocephalemys (347 specimens from ca 40 localities across the known distributional area of all taxa) to investigate the relative importance of disruptive selection, temporary geographic isolation and introgression in their adaptive radiations in the Pleistocene. We confirmed the four main highly supported mitochondrial (mtDNA) clades that were proposed as four species in a previous pilot study: S. albipes is a sister species of S. griseicauda (both lineages are present on both sides of the GRV), while the second clade is formed by two Afro-alpine species, S. albocaudata (east of GRV) and the undescribed Stenocephalemys sp. A (west of GRV). There is a clear elevational gradient in the distribution of the Stenocephalemys taxa with two to three species present at different elevations of the same mountain range. Surprisingly, the nuclear species tree corresponded only a little to the mtDNA tree. Multispecies coalescent models based on six nuclear markers revealed the presence of six separate gene pools (i.e. candidate species), with different topology. Phylogenetic analysis, together with the geographic distribution of the genetic groups, suggests a complex reticulate evolution. We propose a scenario that involves (besides classical allopatric speciation) two cases of disruptive selection along the elevational ecological gradient, multiple crosses of GRV in dry and cold periods of the Pleistocene, followed by hybridization and mtDNA introgression on imperfect reproductive barriers. Spatial expansion of the currently most widespread "albipes" mtDNA clade was followed by population fragmentation, lineage sorting and again by hybridization and mtDNA introgression. Comparison of this genetic structure to other Ethiopian endemic taxa highlight the geographical areas of special conservation concern, where more detailed biodiversity studies should be carried out to prevent many endemic taxa from going extinct even before they are recognized. Copyright © 2017 Elsevier Inc. All rights reserved.

Gradient distribution of persistent organic contaminants along northern slope of central-Himalayas, China.

PubMed

Wang, Xiao-Ping; Yao, Tan-Dong; Cong, Zhi-Yuan; Yan, Xing-Liang; Kang, Shi-Chang; Zhang, Yong

2006-12-15

High mountains may serve as condenser for persistent organic pollutants (POPs) and the vegetation in remote areas has been used as a means to characterized atmospheric concentrations of air pollutants. In this study, organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs) in Himalayan spruce needle samples from Zhangmu-Nyalam region (central-Himalayas) were analyzed and the altitudinal gradient of these pollutants was investigated. Total HCHs and DDTs concentration in needles were in the range of 1.3-2.9 ng g(-1) dry weight and 1.7-11 ng g(-1) dry weight, which were lower than concentrations reported in spruce needles from Alps, however higher than concentrations in conifer needles from mountain areas of Alberta. Total Himalayan spruce needle PAHs was below 600 ng g(-1) and fluorene, phenanthrene and acenaphthene were abundant individual compounds measured. The ratios of alpha-HCH/gamma-HCH in pine needles were similar with the usual values for technical HCH, implying technical HCHs might be used in this region. The high ratios of o-p'-DDT/p-p'-DDT and no p-p'-DDE measured in this study led to the suspicion that a new source of o-p'-DDT and/or p-p'-DDT existed in this region. In addition, higher ratios of low molecular weight-/high molecular weight-PAHs in this region indicated that petroleum combustion, vehicle emission and low-temperature combustion might be the major contributions of PAH source. To examine the POPs distillation, the analyte concentrations were correlated with altitude. The more volatile OCPs, alpha-HCH, gamma-HCH, aldrin and alpha-endosulfan positively correlated with altitude, however, less volatile OCPs (DDT and DDD) inversely related with elevation. Almost all PAHs detected in this area showed positive correlations with altitude. It is worthy to note that heavy PAHs (Benzo[k] fluoranthene and Benzo[a]anthracene) displayed positive correlation, which implied the sources of PAHs were near the sampling sites. The distillation of POPs was strongly affected by the proximity between sampling sites and contaminant sources. If the contaminant sources are close to the mountains, it may be the dominant factor that controls the concentration gradient.

Optimal climate for large trees at high elevations drives patterns of biomass in remote forests of Papua New Guinea.

PubMed

Venter, Michelle; Dwyer, John; Dieleman, Wouter; Ramachandra, Anurag; Gillieson, David; Laurance, Susan; Cernusak, Lucas A; Beehler, Bruce; Jensen, Rigel; Bird, Michael I

2017-11-01

Our ability to model global carbon fluxes depends on understanding how terrestrial carbon stocks respond to varying environmental conditions. Tropical forests contain the bulk of the biosphere's carbon. However, there is a lack of consensus as to how gradients in environmental conditions affect tropical forest carbon. Papua New Guinea (PNG) lies within one of the largest areas of contiguous tropical forest and is characterized by environmental gradients driven by altitude; yet, the region has been grossly understudied. Here, we present the first field assessment of aboveground biomass (AGB) across three main forest types of PNG using 193 plots stratified across 3,100-m elevation gradient. Unexpectedly, AGB had no direct relationship to rainfall, temperature, soil, or topography. Instead, natural disturbances explained most variation in AGB. While large trees (diameter at breast height > 50 cm) drove altitudinal patterns of AGB, resulting in a major peak in AGB (2,200-3,100 m) and some of the most carbon-rich forests at these altitudes anywhere. Large trees were correlated to a set of climatic variables following a hump-shaped curve. The set of "optimal" climatic conditions found in montane cloud forests is similar to that of maritime temperate areas that harbor the largest trees in the world: high ratio of precipitation to evapotranspiration (2.8), moderate mean annual temperature (13.7°C), and low intra-annual temperature range (7.5°C). At extreme altitudes (2,800-3,100 m), where tree diversity elsewhere is usually low and large trees are generally rare or absent, specimens from 18 families had girths >70 cm diameter and maximum heights 20-41 m. These findings indicate that simple AGB-climate-edaphic models may not be suitable for estimating carbon storage in forests where optimal climate niches exist. Our study, conducted in a very remote area, suggests that tropical montane forests may contain greater AGB than previously thought and the importance of securing their future under a changing climate is therefore enhanced. © 2017 John Wiley & Sons Ltd.

Woody plant richness and NDVI response to drought events in Catalonian (northeastern Spain) forests.

PubMed

Lloret, F; Lobo, A; Estevan, H; Maisongrande, P; Vayreda, J; Terradas, J

2007-09-01

The role of species diversity on ecosystem resistance in the face of strong environmental fluctuations has been addressed from both theoretical and experimental viewpoints to reveal a variety of positive and negative relationships. Here we explore empirically the relationship between the richness of forest woody species and canopy resistance to extreme drought episodes. We compare richness data from an extensive forest inventory to a temporal series of satellite imagery that estimated drought impact on forest canopy as NDVI (normalized difference vegetation index) anomalies of the dry summer in 2003 in relation to records of previous years. We considered five different types of forests that are representative of the main climatic and altitudinal gradients of the region, ranging from lowland Mediterranean to mountain boreal-temperate climates. The observed relationship differed among forest types and interacted with the climate, summarised by the Thorntwaite index. In Mediterranean Pinus halepensis forests, NDVI decreased during the drought. This decrease was stronger in forests with lower richness. In Mediterranean evergreen forests of Quercus ilex, drought did not result in an overall NDVI loss, but lower NDVI values were observed in drier localities with lower richness, and in more moist localities with higher number of species. In mountain Pinus sylvestris forests NDVI decreased, mostly due to the drought impact on drier localities, while no relation to species richness was observed. In moist Fagus sylvatica forests, NDVI only decreased in plots with high richness. No effect of drought was observed in the high mountain Pinus uncinata forests. Our results show that a shift on the diversity-stability relationship appears across the regional, climatic gradient. A positive relationship appears in drier localities, supporting a null model where the probability of finding a species able to cope with drier conditions increases with the number of species. However, in more moist localities we hypothesize that the proportion of drought-sensitive species would increase in richer localities, due to a higher likelihood of co-occurrence of species that share moist climatic requirements. The study points to the convenience of considering the causes of disturbance in relation to current environmental gradients and historical environmental constraints on the community.

High photobiont diversity in the common European soil crust lichen Psora decipiens.

PubMed

Ruprecht, Ulrike; Brunauer, Georg; Türk, Roman

2014-01-01

The genetic diversity of green algal photobionts (chlorobionts) in soil crust forming lichens was studied as part of the SCIN-project (Soil Crust InterNational). A total of 64 lichen samples were collected from four different sites along latitudinal and altitudinal gradients in Europe (Tabernas/Spain; Hochtor-Großglockner/Austria; Gynge Alvar/Sweden; Ruine Homburg/Germany). The dominant lichen species at all four sites was Psora decipiens , often occurring with Buellia elegans, Fulgensia bracteata, F. fulgens and Peltigera rufescens. Genetic identification of chlorobionts was carried out using the nuclear marker (nrITS) and a chloroplast marker ( psb L-J). We found P. decipiens to be associated with several different species of Trebouxia and Asterochloris , although previously described to only have Asterochloris sp. The phylogenetic analyses revealed a high chlorobiont diversity with 12 well supported clades, including Trebouxia asymmetrica , T. jamesii , T. impressa and other, as yet taxonomically unidentified clades ( Trebouxia sp. URa1-4, T . sp. URa6, T . sp. URa7-13). Additionally, five clades of Asterochloris were identified ( A. magna, A. sp. URa14 -17). Most of the chlorobiont species appeared to be cosmopolitan, but five clades were unevenly distributed between the sampling sites with only Trebouxia being found in the warm and dry Spanish habitats and combinations of Trebouxia and Asterochloris in the cooler and more humid habitats. The wide range of chlorobiont species might contribute to the observed domination of P. decipiens at all four research sites of the SCIN project which range from a desert in Spain to an alpine site in the Alps of Austria.

Temporal variation in bird and resource abundance across an elevational gradient in Hawaii

USGS Publications Warehouse

Hart, Patrick J.; Woodworth, Bethany L.; Camp, Richard J.; Turner, Kathryn; McClure, Katherine; Goodall, Katherine; Henneman, Carlene; Spiegel, Caleb; Lebrun, Jaymi; Tweed, Erik; Samuel, Michael

2011-01-01

We documented patterns of nectar availability and nectarivorous bird abundance over ~3 years at nine study sites across an 1,800-m elevational gradient on Hawaii Island to investigate the relationship between resource variation and bird abundance. Flower density (flowers ha-1) and nectar energy content were measured across the gradient for the monodominant 'Ōhi'a (Metrosideros polymorpha). Four nectarivorous bird species were captured monthly in mist nets and surveyed quarterly with point-transect distance sampling at each site to examine patterns of density and relative abundance. Flowering peaks were associated with season but not rainfall or elevation. Bird densities peaked in the winter and spring of each year at high elevations, but patterns were less clear at middle and low elevations. Variability in bird abundance was generally best modeled as a function of elevation, season, and flower density, but the strength of the latter effect varied with species. The low elevations had the greatest density of flowers but contained far fewer individuals of the two most strongly nectarivorous species. There is little evidence of large-scale altitudinal movement of birds in response to 'Ōhi'a flowering peaks. The loose relationship between nectar and bird abundance may be explained by a number of potential mechanisms, including (1) demographic constraints to movement; (2) nonlimiting nectar resources; and (3) the presence of an "ecological trap," whereby birds are attracted by the high resource abundance of, but suffer increased mortality at, middle and low elevations as a result of disease.

Zoogeography of epigean freshwater Amphipoda (Crustacea) in Romania: fragmented distributions and wide altitudinal variability.

PubMed

Copilaș-Ciocianu, Denis; Grabowski, Michał; Pârvulescu, Lucian; Petrusek, Adam

2014-12-08

Inland epigean freshwater amphipods of Romania are diverse and abundant for this region has a favourable geographical position between the Balkans and the Black Sea. Excluding Ponto-Caspian species originating in brackish waters and freshwater subterranean taxa, there are 11 formally recognized epigean freshwater species recorded from this country. They belong to 3 genera, each representing a different family: Gammarus (Gammaridae, 8 species or species complexes), Niphargus (Niphargidae, 2 epigean species) and Synurella (Crangonyctidae, one species). Their large-scale distribution patterns nevertheless remain obscure due to insufficient data, consequently limiting biogeographical interpretations. We provide extensive new data with high resolution distribution maps, thus improving the knowledge of the ranges of these taxa. Gammarus species display substantial altitudinal variability and patchy, fragmented distribution patterns. They occur abundantly, particularly in springs and streams, from lowlands to sub-mountainous and mountainous regions. In the light of recent molecular research, we hypothesize that the complex geomorphological dynamics of the Carpathian region during the Late Tertiary probably contributed to their allopatric distribution pattern. Contrasting with Gammarus, the genera Niphargus and Synurella exhibit low altitudinal variability, broad ecological valences and overlapping distributions, being widespread throughout the lowlands. The current distribution of N. hrabei and N. valachicus seems to be linked to the extent of the Paratethys during the Early Pliocene or Pleistocene. We further discuss the taxonomic validity of two synonymized and one apparently undescribed taxon, and provide an updated pictorial identification key that includes all taxa and forms discussed in our study. The mosaic distribution of epigean freshwater amphipod species in Romania shows that this region is particularly suitable for phylo- and biogeographical analyses of this group.

Altitudinal and climatic adaptation is mediated by flowering traits and FRI, FLC, and PHYC genes in Arabidopsis.

PubMed

Méndez-Vigo, Belén; Picó, F Xavier; Ramiro, Mercedes; Martínez-Zapater, José M; Alonso-Blanco, Carlos

2011-12-01

Extensive natural variation has been described for the timing of flowering initiation in many annual plants, including the model wild species Arabidopsis (Arabidopsis thaliana), which is presumed to be involved in adaptation to different climates. However, the environmental factors that might shape this genetic variation, as well as the molecular bases of climatic adaptation by modifications of flowering time, remain mostly unknown. To approach both goals, we characterized the flowering behavior in relation to vernalization of 182 Arabidopsis wild genotypes collected in a native region spanning a broad climatic range. Phenotype-environment association analyses identified strong altitudinal clines (0-2600 m) in seven out of nine flowering-related traits. Altitudinal clines were dissected in terms of minimum winter temperature and precipitation, indicating that these are the main climatic factors that might act as selective pressures on flowering traits. In addition, we used an association analysis approach with four candidate genes, FRIGIDA (FRI), FLOWERING LOCUS C (FLC), PHYTOCHROME C (PHYC), and CRYPTOCHROME2, to decipher the genetic bases of this variation. Eleven different loss-of-function FRI alleles of low frequency accounted for up to 16% of the variation for most traits. Furthermore, an FLC allelic series of six novel putative loss- and change-of-function alleles, with low to moderate frequency, revealed that a broader FLC functional diversification might contribute to flowering variation. Finally, environment-genotype association analyses showed that the spatial patterns of FRI, FLC, and PHYC polymorphisms are significantly associated with winter temperatures and spring and winter precipitations, respectively. These results support that allelic variation in these genes is involved in climatic adaptation.

Comparison of Relative Humidity obtained from SAPHIR on board Megha-Tropiques and Ground based Microwave Radiometer Profiler over an equatorial station

NASA Astrophysics Data System (ADS)

Renju, Ramachandran Pillai; Uma, K. N.; Krishna Moorthy, K.; Mathew, Nizy; Raju C, Suresh

A comparison has been made between the SAPHIR on board Megha-Tropiques (MT) derived Relative Humidity (RH (%)) with that derived from a ground based multi-frequency Microwave Radiometer Profiler (MRP) observations over an equatorial station Thiruvananthapuram (8.5(°) N and 76.9(°) E) for a one year period. As a first step, the validation of MRP has been made against the radiosonde for two years (2010 and 2011) during the Indian monsoon period July-September. This analysis shows a wet bias below 6 km and dry bias above. The comparison between the MRP and the MT derived RH has been made at five different altitudinal levels (0.75, 2.25, 4.0, 6.25 and 9.2 km range) strictly under clear sky condition. The regression analysis between the two reveals very good correlation (>0.8) in the altitudinal layer of 2.25 to 6.25 km. The differences between the two observations had also been explained interms of percentage of occurrence between MT and the MRP at each altitudinal layer. About 70-80% of the time, the difference in the RH is found to below 10% at first three layer. The RMSE of 2% is observed at almost all the height layers. The differences have been attributed to the different measurement and retrieval techniques involved in the ground based and satellite based measurements. Since MRP frequecy channels are not sensitive to small water vapor variabilities above 6 km, large differences are observed. Radiative Transfer computation for the channels of both MRP and SAPHIR will be carried out to understand the variabilities.

Carbon dioxide concentration in caves and soils in an alpine setting: implications for speleothem fabrics and their palaeoclimate significance

NASA Astrophysics Data System (ADS)

Borsato, Andrea; Frisia, Silvia; Miorandi, Renza

2015-04-01

Carbon dioxide concentration in soils controls carbonate dissolution, soil CO2 efflux to the atmosphere, and CO2 transfer to the subsurface that lead, ultimately, to speleothem precipitation. Systematic studies on CO2 concentration variability in soil and caves at regional scale are, however, few. Here, the systematic investigation of CO2 concentration in caves and soils in a temperate, Alpine region along a 2,100 m altitudinal range transect, which corresponds to a mean annual temperature (MAT) range of 12°C is presented. Soil pCO2 is controlled by the elevation and MAT and exhibits strong seasonality, which follows surface air temperature with a delay of about a month. The aquifer pCO2, by contrast, is fairly constant throughout the year, and it is primarily influenced by summer soil pCO2. Cave CO2 concentration is a balance between the CO2 influx and CO2 efflux, where the efflux is controlled by the cave ventilation, which is responsible for low pCO2 values recorded in most of the caves with respect to soil levels. Carbon dioxide in the innermost part of the studied caves exhibits a clear seasonal pattern. Thermal convection is the most common mechanism causing higher ventilation and low cave air pCO2 levels during the winter season: this promotes CO2 degassing and higher supersaturation in the drip water and, eventually, higher speleothem growth rates during winter. The combined influence of three parameters - dripwater pCO2, dripwater Ca content, and cave air pCO2 - all related to the infiltration elevation and MAT directly controls calcite supersaturation in dripwater. Four different altitudinal belts are then defined, which reflect temperature-dependent saturation state of dripwaters. These belts broadly correspond to vegetation zones: the lower montane (100 to 800 m asl), the upper montane (800 to 1600 m asl), the subalpine (1600 to 2200 m asl) and the Alpine (above 2200 m asl). Each altitudinal belt is characterised by different calcite fabrics, which can shift upward/downward in elevation as a response to temperature increase/decrease through time. In the lower and upper montane zones the columnar types (compact, open, fascicular optic) are the most common fabrics, with the microcrystalline type most typical of the upper montane zone. The dendritic fabric becomes predominant in the higher upper montane and lower subalpine zones. The higher subalpine to lower alpine zones the only speleothem actually forming is moonmilk. Eventually, the occurrence of "altitudinal" fabrics within the vertical growth axis of a stalagmite is indicative of changes in the MAT through time Therefore, fabric changes in fossil speleothems in temperate climate settings can be potentially used to reconstruct regional MAT changes in the past.

Hydrological significance of soil frost for pre-alpine areas

NASA Astrophysics Data System (ADS)

Stähli, Manfred

2017-03-01

Soil frost can have a substantial impact on water flows at the soil surface and-potentially-alter the dynamics of catchment runoff. While these findings are mainly based on studies from alpine and Northern-latitude areas (including permafrost areas), little is known about the significance of soil frost for hydrology in pre-alpine areas, i.e. the region at the transition from central European lowlands to high-alpine areas. Here I synthesize soil temperature data and soil frost observations from ten sites in Switzerland to assess the occurrence of soil frost and to determine its impact on catchment runoff. In addition, a well-established numerical model was used to reconstruct the presence of soil frost in two first-order catchments for single runoff events and winters. The data clearly demonstrates that shallow soil frost has formed regularly in this altitudinal range over the past decade. The presence of a frozen soil surface was found to be highly variable among the sites under study and did not significantly correlate with altitude or forest density. For the first-order catchments, it was not possible to relate important flood peaks or increased runoff coefficients to winter situations with substantial soil frost. Thus, the present analysis suggests that although soil frost is widespread and regularly occurring at this altitudinal range, it has no significant impact on winter runoff in pre-alpine watersheds.

Isotopic variability of cave bears (δ15N, δ13C) across Europe during MIS 3

NASA Astrophysics Data System (ADS)

Krajcarz, Magdalena; Pacher, Martina; Krajcarz, Maciej T.; Laughlan, Lana; Rabeder, Gernot; Sabol, Martin; Wojtal, Piotr; Bocherens, Hervé

2016-01-01

Collagen, the organic fraction of bone, records the isotopic parameters of consumed food for carbon (δ13C) and nitrogen (δ15N). This relationship of isotopic signature between diet and tissue is an important tool for the study of dietary preferences of modern and fossil animal species. Since the first information on the isotopic signature of cave bear was reported, numerous data from Europe have become available. The goal of this work is to track the geographical variation of cave bear collagen isotopic values in Europe during Marine Isotopic Stage 3 (about 60,000-25,000 yr BP). In this study the results of new δ13C and δ15N isotopic analyses of cave bear collagen from four Central-Eastern European sites are presented, as well as a review of all published isotopic data for cave bears of the same period. The main conclusion is a lack of geographical East-West pattern in the variations of δ13C and δ15N values of cave bear collagen. Moreover, no relationship was found between cave bear taxonomy and isotopic composition. The cave bears from Central-Eastern Europe exhibit δ13C and δ15N values near the average of the range of Central, Western and Southern European cave bears. Despite the fact that most cave bear sites follow an altitudinal gradient, separate groups of sites exhibit shift in absolute values of δ13C, what disturbs an altitude-related isotopic pattern. The most distinct groups are: high Alpine sites situated over 1500 m a.s.l. - in terms of δ13C; and two Romanian sites Peştera cu Oase and Urşilor - in case of δ15N. Although the cave bear isotopic signature is driven by altitude, the altitudinal adjustment of isotopic data is not enough to explain the isotopic dissimilarity of these cave bears. The unusually high δ15N signature of mentioned Romanian sites is an isolated case in Europe. Cave bears from relatively closely situated Central-Eastern European sites and other Romanian sites are more similar to Western European than to Romanian populations in terms of isotopic composition, and probably ecology.

Soil microbial biomass, activity and community composition along altitudinal gradients in the High Arctic (Billefjorden, Svalbard)

NASA Astrophysics Data System (ADS)

Kotas, Petr; Šantrůčková, Hana; Elster, Josef; Kaštovská, Eva

2018-03-01

The unique and fragile High Arctic ecosystems are vulnerable to global climate warming. The elucidation of factors driving microbial distribution and activity in arctic soils is essential for a comprehensive understanding of ecosystem functioning and its response to environmental change. The goals of this study were to investigate microbial biomass and activity, microbial community structure (MCS), and their environmental controls in soils along three elevational transects in the coastal mountains of Billefjorden, central Svalbard. Soils from four different altitudes (25, 275, 525 and 765 m above sea level) were analyzed for a suite of characteristics including temperature regimes, organic matter content, base cation availability, moisture, pH, potential respiration, and microbial biomass and community structure using phospholipid fatty acids (PLFAs). We observed significant spatial heterogeneity of edaphic properties among transects, resulting in transect-specific effects of altitude on most soil parameters. We did not observe any clear elevation pattern in microbial biomass, and microbial activity revealed contrasting elevational patterns between transects. We found relatively large horizontal variability in MCS (i.e., between sites of corresponding elevation in different transects), mainly due to differences in the composition of bacterial PLFAs, but also a systematic altitudinal shift in MCS related to different habitat preferences of fungi and bacteria, which resulted in high fungi-to-bacteria ratios at the most elevated sites. The biological soil crusts on these most elevated, unvegetated sites can host microbial assemblages of a size and activity comparable to those of the arctic tundra ecosystem. The key environmental factors determining horizontal and vertical changes in soil microbial properties were soil pH, organic carbon content, soil moisture and Mg2+ availability.

Temporal variations of mobile carbohydrates in Abies fargesii at the upper tree limits.

PubMed

Dang, H S; Zhang, K R; Zhang, Q F; Xu, Y M

2015-01-01

Low temperatures are associated high-altitude treelines, but the functional mechanism of treeline formation remains controversial. The relative contributions of carbon limitation (source activity) and growth limitation (sink activity) require more tests across taxa and regions. We examined temporal variations of mobile carbon supply in different tissues of Abies fargesii across treeline ecotones on north- and south-facing slopes of the Qinling Mountains, China. Non-structural carbohydrate (NSC) concentrations in tissues along the altitudinal gradient on both slopes changed significantly in the early and late growing season, but not in the mid-growing season, indicating the season-dependent carbon supply status. Late in the growing season on both slopes, trees at the upper limits had the highest NSC concentrations and total soluble sugars and lowest starch concentrations compared to trees at the lower elevations. NSC concentrations tended to increase in needles and branches throughout the growing season with increasing elevation on both slopes, but declined in roots and stems. NSC concentrations across sampling dates also indicated increases in needles and branches, and decreases in roots and stem with increasing elevation. Overall altitudinal trends of NSC in A. fargesii revealed no depletion of mobile carbon reserves at upper elevation limits, suggesting limitation of sink activity dominates tree life across treeline ecotones in both north- and south-facing slopes. Carbon reserves in storage tissues (especially roots) in the late growing season might also play an important role in winter survival and early growth in spring at upper elevations on both slopes, which define the uppermost limit of A. fargesii. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

Altitudinal changes in temperature responses of net photosynthesis and dark respiration in tropical bryophytes.

PubMed

Wagner, Sebastian; Zotz, Gerhard; Salazar Allen, Noris; Bader, Maaike Y

2013-03-01

There is a conspicuous increase of poikilohydric organisms (mosses, liverworts and macrolichens) with altitude in the tropics. This study addresses the hypothesis that the lack of bryophytes in the lowlands is due to high-temperature effects on the carbon balance. In particular, it is tested experimentally whether temperature responses of CO(2)-exchange rates would lead to higher respiratory carbon losses at night, relative to potential daily gains, in lowland compared with lower montane forests. Gas-exchange measurements were used to determine water-, light-, CO(2)- and temperature-response curves of net photosynthesis and dark respiration of 18 tropical bryophyte species from three altitudes (sea level, 500 m and 1200 m) in Panama. Optimum temperatures of net photosynthesis were closely related to mean temperatures in the habitats in which the species grew at the different altitudes. The ratio of dark respiration to net photosynthesis at mean ambient night and day temperatures did not, as expected, decrease with altitude. Water-, light- and CO(2)-responses varied between species but not systematically with altitude. Drivers other than temperature-dependent metabolic rates must be more important in explaining the altitudinal gradient in bryophyte abundance. This does not discard near-zero carbon balances as a major problem for lowland species, but the main effect of temperature probably lies in increasing evaporation rates, thus restricting the time available for photosynthetic carbon gain, rather than in increasing nightly respiration rates. Since optimum temperatures for photosynthesis were so fine tuned to habitat temperatures we analysed published temperature responses of bryophyte species worldwide and found the same pattern on the large scale as we found along the tropical mountain slope we studied.

Altitudinal changes in temperature responses of net photosynthesis and dark respiration in tropical bryophytes

PubMed Central

Wagner, Sebastian; Zotz, Gerhard; Salazar Allen, Noris; Bader, Maaike Y.

2013-01-01

Background and Aims There is a conspicuous increase of poikilohydric organisms (mosses, liverworts and macrolichens) with altitude in the tropics. This study addresses the hypothesis that the lack of bryophytes in the lowlands is due to high-temperature effects on the carbon balance. In particular, it is tested experimentally whether temperature responses of CO2-exchange rates would lead to higher respiratory carbon losses at night, relative to potential daily gains, in lowland compared with lower montane forests. Methods Gas-exchange measurements were used to determine water-, light-, CO2- and temperature-response curves of net photosynthesis and dark respiration of 18 tropical bryophyte species from three altitudes (sea level, 500 m and 1200 m) in Panama. Key Results Optimum temperatures of net photosynthesis were closely related to mean temperatures in the habitats in which the species grew at the different altitudes. The ratio of dark respiration to net photosynthesis at mean ambient night and day temperatures did not, as expected, decrease with altitude. Water-, light- and CO2-responses varied between species but not systematically with altitude. Conclusions Drivers other than temperature-dependent metabolic rates must be more important in explaining the altitudinal gradient in bryophyte abundance. This does not discard near-zero carbon balances as a major problem for lowland species, but the main effect of temperature probably lies in increasing evaporation rates, thus restricting the time available for photosynthetic carbon gain, rather than in increasing nightly respiration rates. Since optimum temperatures for photosynthesis were so fine tuned to habitat temperatures we analysed published temperature responses of bryophyte species worldwide and found the same pattern on the large scale as we found along the tropical mountain slope we studied. PMID:23258418

Natural Genetic Variation and Candidate Genes for Morphological Traits in Drosophila melanogaster

PubMed Central

Carreira, Valeria Paula; Mensch, Julián; Hasson, Esteban; Fanara, Juan José

2016-01-01

Body size is a complex character associated to several fitness related traits that vary within and between species as a consequence of environmental and genetic factors. Latitudinal and altitudinal clines for different morphological traits have been described in several species of Drosophila and previous work identified genomic regions associated with such variation in D. melanogaster. However, the genetic factors that orchestrate morphological variation have been barely studied. Here, our main objective was to investigate genetic variation for different morphological traits associated to the second chromosome in natural populations of D. melanogaster along latitudinal and altitudinal gradients in Argentina. Our results revealed weak clinal signals and a strong population effect on morphological variation. Moreover, most pairwise comparisons between populations were significant. Our study also showed important within-population genetic variation, which must be associated to the second chromosome, as the lines are otherwise genetically identical. Next, we examined the contribution of different candidate genes to natural variation for these traits. We performed quantitative complementation tests using a battery of lines bearing mutated alleles at candidate genes located in the second chromosome and six second chromosome substitution lines derived from natural populations which exhibited divergent phenotypes. Results of complementation tests revealed that natural variation at all candidate genes studied, invected, Fasciclin 3, toucan, Reticulon-like1, jing and CG14478, affects the studied characters, suggesting that they are Quantitative Trait Genes for morphological traits. Finally, the phenotypic patterns observed suggest that different alleles of each gene might contribute to natural variation for morphological traits. However, non-additive effects cannot be ruled out, as wild-derived strains differ at myriads of second chromosome loci that may interact epistatically with mutant alleles. PMID:27459710

Integrating Evolutionary and Functional Tests of Adaptive Hypotheses: A Case Study of Altitudinal Differentiation in Hemoglobin Function in an Andean Sparrow, Zonotrichia capensis

PubMed Central

Cheviron, Zachary A.; Natarajan, Chandrasekhar; Projecto-Garcia, Joana; Eddy, Douglas K.; Jones, Jennifer; Carling, Matthew D.; Witt, Christopher C.; Moriyama, Hideaki; Weber, Roy E.; Fago, Angela; Storz, Jay F.

2014-01-01

In air-breathing vertebrates, the physiologically optimal blood-O2 affinity is jointly determined by the prevailing partial pressure of atmospheric O2, the efficacy of pulmonary O2 transfer, and internal metabolic demands. Consequently, genetic variation in the oxygenation properties of hemoglobin (Hb) may be subject to spatially varying selection in species with broad elevational distributions. Here we report the results of a combined functional and evolutionary analysis of Hb polymorphism in the rufous-collared sparrow (Zonotrichia capensis), a species that is continuously distributed across a steep elevational gradient on the Pacific slope of the Peruvian Andes. We integrated a population genomic analysis that included all postnatally expressed Hb genes with functional studies of naturally occurring Hb variants, as well as recombinant Hb (rHb) mutants that were engineered through site-directed mutagenesis. We identified three clinally varying amino acid polymorphisms: Two in the αA-globin gene, which encodes the α-chain subunits of the major HbA isoform, and one in the αD-globin gene, which encodes the α-chain subunits of the minor HbD isoform. We then constructed and experimentally tested single- and double-mutant rHbs representing each of the alternative αA-globin genotypes that predominate at different elevations. Although the locus-specific patterns of altitudinal differentiation suggested a history of spatially varying selection acting on Hb polymorphism, the experimental tests demonstrated that the observed amino acid mutations have no discernible effect on respiratory properties of the HbA or HbD isoforms. These results highlight the importance of experimentally validating the hypothesized effects of genetic changes in protein function to avoid the pitfalls of adaptive storytelling. PMID:25135942

Animal Fascioliasis: Perspectives from high altitudinal regions.

PubMed

Lyngdoh, Damanbha; Sharma, Sunil; Roy, Bishnupada; Tandon, Veena

2016-12-15

The parasitic flukes of the genus Fasciola (Platyhelminthes: Trematoda: Digenea) cause fascioliasis or liver-rot disease in ruminant livestock in tropical and sub-tropical regions of the world. Classically, two species of Fasciola- F. hepatica and F. gigantica, are universally recognized as taxonomically valid species. Our survey studies on ovid and bovid animals including yak and mithun from high altitudinal mountainous regions in Northeast India revealed the occurrence of Fasciola gigantica and also Fasciola sp.- an intermediate form, at altitudes between 5000 and 14,085 feet above sea level (asl). Two morphotypes- F. hepatica - like and F. gigantica - like, of Fasciola species were reported from the high altitudinal areas of Northeast India; most of these locales constitute new-locality and first records for the occurrence of these liver flukes. Copyright © 2016 Elsevier B.V. All rights reserved.

Disparity in elevational shifts of European trees in response to recent climate warming.

PubMed

Rabasa, Sonia G; Granda, Elena; Benavides, Raquel; Kunstler, Georges; Espelta, Josep M; Ogaya, Romá; Peñuelas, Josep; Scherer-Lorenzen, Michael; Gil, Wojciech; Grodzki, Wojciech; Ambrozy, Slawomir; Bergh, Johan; Hódar, José A; Zamora, Regino; Valladares, Fernando

2013-08-01

Predicting climate-driven changes in plant distribution is crucial for biodiversity conservation and management under recent climate change. Climate warming is expected to induce movement of species upslope and towards higher latitudes. However, the mechanisms and physiological processes behind the altitudinal and latitudinal distribution range of a tree species are complex and depend on each tree species features and vary over ontogenetic stages. We investigated the altitudinal distribution differences between juvenile and adult individuals of seven major European tree species along elevational transects covering a wide latitudinal range from southern Spain (37°N) to northern Sweden (67°N). By comparing juvenile and adult distributions (shifts on the optimum position and the range limits) we assessed the response of species to present climate conditions in relation to previous conditions that prevailed when adults were established. Mean temperature increased by 0.86 °C on average at our sites during the last decade compared with previous 30-year period. Only one of the species studied, Abies alba, matched the expected predictions under the observed warming, with a maximum abundance of juveniles at higher altitudes than adults. Three species, Fagus sylvatica, Picea abies and Pinus sylvestris, showed an opposite pattern while for other three species, such as Quercus ilex, Acer pseudoplatanus and Q. petraea, we were no able to detect changes in distribution. These findings are in contrast with theoretical predictions and show that tree responses to climate change are complex and are obscured not only by other environmental factors but also by internal processes related to ontogeny and demography. © 2013 John Wiley & Sons Ltd.

Using synoptic tracer surveys to assess runoff sources in an Andean headwater catchment in central Chile.

PubMed

Nauditt, A; Soulsby, C; Birkel, C; Rusman, A; Schüth, C; Ribbe, L; Álvarez, P; Kretschmer, N

2017-09-01

Headwater catchments in the Andes provide critical sources of water for downstream areas with large agricultural communities dependent upon irrigation. Data from such remote headwater catchments are sparse, and there is limited understanding of their hydrological function to guide sustainable water management. Here, we present the findings of repeat synoptic tracer surveys as rapid appraisal tools to understand dominant hydrological flow paths in the semi-arid Rio Grande basin, a 572-km 2 headwater tributary of the 11,696-km 2 Limarí basin in central Chile. Stable isotopes in stream water show a typical altitudinal effect, with downstream enrichment in δ 2 H and δ 18 O ratios. Seasonal signals are displayed in the isotopic composition of the springtime melting season water line with a steeper gradient, whilst evaporative effects are represented by lower seasonal gradients for autumn and summer. Concentrations of solutes indexed by electrical conductivity indicate that there are limited contributions of deeper mineralised groundwater to streamflow and that weathering rates vary in the different sub-catchments. Although simplistic, the insights gained from the study could be used to inform the structure and parameterisation of rainfall runoff models to provide seasonal discharge predictions as an evidence base for decision making in local water management.

The peak altitude of H3+ auroral emission: comparison with the ultraviolet

NASA Astrophysics Data System (ADS)

Blake, J.; Stallard, T.; Miller, S.; Melin, H.; O'Donoghue, J.; Baines, K.

2013-09-01

The altitude of Saturn's peak auroral emission has previously been measured for specific cases in both the ultraviolet (UV) and the infrared (IR). Gerard et al [2009] concludes that the night side H2 UV emission is within the range of 800 to 1300 km above the 1-bar pressure surface. However, using colour ratio spectroscopy, Gustin et al [2009] located the emission layer at or above 610 km. Measurements of the infrared auroral altitude was conducted by Stallard et al [2012] on H3+ emissions from nine VIMS Cassini images, resulting in a measurement of 1155 ± 25 km above the 1-bar pressure surface. Here we present data analysed in a manner similar to Stallard et al [2012] on the observations of H3+ emission in twenty images taken by the Visual Infrared Mapping Spectrometer (VIMS) aboard the spacecraft Cassini from the years 2006, 2008 and 2012. The bins covered were 3.39872, 3.51284, 3.64853, 4.18299 and 4.33280 μm. These observations were selected from a set of 15,000 as they contained a useful alignment of the aurorae on the limb and the body of the planet. The specific conditions that had to be met for each image were as follows; minimum integration time of 75 milliseconds per pixel, minimum number of pixels in the x and y direction of 32, the image must include the latitude range of 70 to 90 degrees for either hemisphere and the sub spacecraft angle must be between 0 and 20 degrees. This alignment allowed for the altitudinal profiles to be analysed in terms of the difference between the latitude of aurorae on the limb and on the body of Saturn; thus permitting an investigation into the effects of misalignment. In this instance, misalignment was defined as the difference between the latitude of the peak emission latitude on the planet and the latitude of the limb; assuming the aurorae to be approximately circular. A statistical study by Badman et al [2011] showed that centre of the oval is on average offset anti sunward of the pole by about 1.6 degrees. To account for this, the acceptable error in misalignment was set to be ± 4 degrees. The accepted error range for the altitudinal profiles was set to ± 250 km. It was determined that variations in the measured altitude of the aurorae are predominantly shifted by misalignment, though there is also some natural variation. Using a second order polynomial fit, the altitude with zero misalignment is measured at 1215 ± 119 km. Further still, through comparison of the IR and UV altitudinal emission profiles is had been discovered that regardless of the alignment, the Infrared auroral altitudinal profile drops off in intensity much faster and the Ultraviolet counterpart, declining to less than 10% of maximum intensity before reaching an altitude of 2000 km above the 1 bar pressure surface. Further work is currently underway to investigate the implication for the emissive behaviour of H3 + with altitude.

Multi-source analysis reveals latitudinal and altitudinal shifts in range of Ixodes ricinus at its northern distribution limit.

PubMed

Jore, Solveig; Viljugrein, Hildegunn; Hofshagen, Merete; Brun-Hansen, Hege; Kristoffersen, Anja B; Nygård, Karin; Brun, Edgar; Ottesen, Preben; Sævik, Bente K; Ytrehus, Bjørnar

2011-05-19

There is increasing evidence for a latitudinal and altitudinal shift in the distribution range of Ixodes ricinus. The reported incidence of tick-borne disease in humans is on the rise in many European countries and has raised political concern and attracted media attention. It is disputed which factors are responsible for these trends, though many ascribe shifts in distribution range to climate changes. Any possible climate effect would be most easily noticeable close to the tick's geographical distribution limits. In Norway- being the northern limit of this species in Europe- no documentation of changes in range has been published. The objectives of this study were to describe the distribution of I. ricinus in Norway and to evaluate if any range shifts have occurred relative to historical descriptions. Multiple data sources - such as tick-sighting reports from veterinarians, hunters, and the general public - and surveillance of human and animal tick-borne diseases were compared to describe the present distribution of I. ricinus in Norway. Correlation between data sources and visual comparison of maps revealed spatial consistency. In order to identify the main spatial pattern of tick abundance, a principal component analysis (PCA) was used to obtain a weighted mean of four data sources. The weighted mean explained 67% of the variation of the data sources covering Norway's 430 municipalities and was used to depict the present distribution of I. ricinus. To evaluate if any geographical range shift has occurred in recent decades, the present distribution was compared to historical data from 1943 and 1983. Tick-borne disease and/or observations of I. ricinus was reported in municipalities up to an altitude of 583 metres above sea level (MASL) and is now present in coastal municipalities north to approximately 69°N. I. ricinus is currently found further north and at higher altitudes than described in historical records. The approach used in this study, a multi-source analysis, proved useful to assess alterations in tick distribution.

Placing lochs in their landscapes: linking landscape ecology, ecohydrology and conservation interest in a changing climate

NASA Astrophysics Data System (ADS)

Muir, M. C.; Spray, C. J.; Rowan, J. S.

2011-12-01

Scotland is a country with outstanding freshwater systems providing multiple social, economic and cultural functions as well as ecological services of international importance. Scotland's lakes (locally termed lochs) occupy approximately 3% of the country's land mass and contain more than 90% of Great Britain's total freshwater resource. With over 25,000 lochs (surface area greater than 0.1 hectares) standing freshwaters are an iconic part of Scotland's landscape and they come in a myriad of forms and sizes contributing outstanding geodiversity as well as habitats of international importance for numerous species of conservation interest. There is undoubtedly a need to protect the conservation interests of designated sites in the face of changing loch and catchment pressures - which include diffuse pollutants, morphological modification, recreation and invasive species. Climate change presents a new set of challenges with potential impacts across the entire standing water resource base and predicting how these systems might respond to these changes greatly amplifies uncertainties implicit in their environmental management. Global climate change is predicted to be a major cause of change across all ecosystems and there are particular concerns about impacts on freshwater systems due to the coupling of impacts to both hydrology and ecology. Climate change is likely to affect the hydrological cycle in a number of ways, most significantly through changing temperature and precipitation patterns, intensities and extremes. These changes, coupled with reduced snow and ice cover, frequency and duration, will lead to changes in soil moisture conditions and subsequently runoff. This is turn will impact on river flow, loch water levels, epilimnic temperatures, nutrient availability and, subsequently, the ecological structure and function of the entire standing water system. For some species these habitat changes will push them to the very limits of their natural tolerances and a number species ranges are already documented to be changing, with species 'climate envelopes' (the geographic ranges with conditions suitable for species life) showing latitudinal moves North and altitudinal movement up gradients. These changes will have a serious effect on species composition and for those species in Scotland currently at their latitudinal/altitudinal limits could lead to local extinctions. For species and habitats which are geographically fixed, like lochs, these changes will also lead to a necessary rethinking of current paradigms surrounding environmental protection in static reserves and understandings of 'naturalness' which has been key to the compositionalist philosophy which has underpinned conservation efforts over the last half century. The aim of this paper is to discuss the potential impacts of climate change to the ecohydrology and conservation interest of lochs in Scotland. We use a landscape ecology framework to place changes in the ecohydrology of standing freshwaters within the challenging context of the physical and human landscapes in which they sit.

Examining Environmental Gradients with satellite data in permafrost regions - the current state of the ESA GlobPermafrost initative

NASA Astrophysics Data System (ADS)

Grosse, G.; Bartsch, A.; Kääb, A.; Westermann, S.; Strozzi, T.; Wiesmann, A.; Duguay, C. R.; Seifert, F. M.; Obu, J.; Nitze, I.; Heim, B.; Haas, A.; Widhalm, B.

2017-12-01

Permafrost cannot be directly detected from space, but many surface features of permafrost terrains and typical periglacial landforms are observable with a variety of EO sensors ranging from very high to medium resolution at various wavelengths. In addition, landscape dynamics associated with permafrost changes and geophysical variables relevant for characterizing the state of permafrost, such as land surface temperature or freeze-thaw state can be observed with spaceborne Earth Observation. Suitable regions to examine environmental gradients across the Arctic have been defined in a community white paper (Bartsch et al. 2014, hdl:10013/epic.45648.d001). These transects have been revised and adjusted within the DUE GlobPermafrost initiative of the European Space Agency. The ESA DUE GlobPermafrost project develops, validates and implements Earth Observation (EO) products to support research communities and international organisations in their work on better understanding permafrost characteristics and dynamics. Prototype product cases will cover different aspects of permafrost by integrating in situ measurements of subsurface and surface properties, Earth Observation, and modelling to provide a better understanding of permafrost today. The project will extend local process and permafrost monitoring to broader spatial domains, support permafrost distribution modelling, and help to implement permafrost landscape and feature mapping in a GIS framework. It will also complement active layer and thermal observing networks. Both lowland (latitudinal) and mountain (altitudinal) permafrost issues are addressed. The status of the Permafrost Information System and first results will be presented. Prototypes of GlobPermafrost datasets include: Modelled mean annual ground temperature by use of land surface temperature and snow water equivalent from satellites Land surface characterization including shrub height, land cover and parameters related to surface roughness Trends from Landsat time-series over selected transects For selected sites: subsidence, ground fast lake ice, land surface features and rock glacier monitoring

Surface soil phytoliths as vegetation and altitude indicators: a study from the southern Himalaya

PubMed Central

An, Xiaohong; Lu, Houyuan; Chu, Guoqiang

2015-01-01

Phytoliths represent one of the few available altitudinal vegetation proxies for mountain ecosystems. This study analyzed 41 topsoil phytolith samples collected from five altitudinal zones in the southern Himalaya as far as, and beyond, the timberline, from tropical forest (up to 1,000 m a.s.l.) to subtropical forest (1,000–2,000 m a.s.l.), to temperate forest (2,000–3,000 m a.s.l.), to subalpine forest (3,000–4,100 m a.s.l.) and finally to alpine scrub (4,100–5,200 m a.s.l.). The statistical results show a good correlation between phytolith assemblages and these five altitudinal vegetation zones: the five phytolith assemblages identified effectively differentiated these five altitudinal vegetation zones. In particular, coniferous phytoliths accurately indicated the timberline. Additionally, we tested the phytolith index Ic (a proxy for estimating the percentage of Pooideae vis-à-vis the total grass content) as a quantifier of phytolith variety versus altitude. Ic increased along altitude, as expected. An investigation of phytoliths provided an initial basis for the analysis of the composition of gramineous vegetation. Furthermore, redundancy analysis and discriminant analysis also suggested a significant correlation between phytolith assemblages and altitude. Our research therefore provides an up-to-date analogue for the reconstruction of changes to palaeovegetation and palaeoaltitude in mountainous areas. PMID:26500137

Mercury accumulation in the surface layers of mountain soils: a case study from the Karkonosze Mountains, Poland.

PubMed

Szopka, Katarzyna; Karczewska, Anna; Kabała, Cezary

2011-06-01

The study was aimed to examine total concentrations and pools of Hg in surface layers of soils in the Karkonosze Mountains, dependent on soil properties and site locality. Soil samples were collected from a litter layer and the layers 0-10 cm and 10-20 cm, at 68 sites belonging to the net of a monitoring system, in two separate areas, and in three altitudinal zones: below 900 m, 900-1100 m, and over 1100 m. Air-borne pollution was the major source of mercury in soils. Hg has accumulated mainly in the litter (where its concentrations were the highest), and in the layer 0-10 cm. Hg concentrations in all samples were in the range 0.04-0.97 mg kg(-1), with mean values 0.38, 0.28, and 0.14 mg kg(-1) for litter and the layers 0-10 cm and 10-20 cm, respectively. The highest Hg concentrations in the litter layer were found in the intermediate altitudinal zone, whereas Hg concentrations in the layer 0-10 cm increased with increasing altitude. Soil quality standard for protected areas (0.50 mg kg(-1)) was exceeded in a few sites. The pools of Hg accumulated in soils were in the range: 0.8-84.8 mg m(-2), with a mean value of 16.5 mg m(-2), and they correlated strongly with the pools of stored organic matter. Copyright © 2011 Elsevier Ltd. All rights reserved.

Using Morphological, Molecular and Climatic Data to Delimitate Yews along the Hindu Kush-Himalaya and Adjacent Regions

PubMed Central

Poudel, Ram C.; Möller, Michael; Gao, Lian-Ming; Ahrends, Antje; Baral, Sushim R.; Liu, Jie; Thomas, Philip; Li, De-Zhu

2012-01-01

Background Despite the availability of several studies to clarify taxonomic problems on the highly threatened yews of the Hindu Kush-Himalaya (HKH) and adjacent regions, the total number of species and their exact distribution ranges remains controversial. We explored the use of comprehensive sets of morphological, molecular and climatic data to clarify taxonomy and distributions of yews in this region. Methodology/Principal Findings A total of 743 samples from 46 populations of wild yew and 47 representative herbarium specimens were analyzed. Principle component analyses on 27 morphological characters and 15 bioclimatic variables plus altitude and maximum parsimony analysis on molecular ITS and trnL-F sequences indicated the existence of three distinct species occurring in different ecological (climatic) and altitudinal gradients along the HKH and adjacent regions Taxus contorta from eastern Afghanistan to the eastern end of Central Nepal, T. wallichiana from the western end of Central Nepal to Northwest China, and the first report of the South China low to mid-elevation species T. mairei in Nepal, Bhutan, Northeast India, Myanmar and South Vietnam. Conclusion/Significance The detailed sampling and combination of different data sets allowed us to identify three clearly delineated species and their precise distribution ranges in the HKH and adjacent regions, which showed no overlap or no distinct hybrid zone. This might be due to differences in the ecological (climatic) requirements of the species. The analyses further provided the selection of diagnostic morphological characters for the identification of yews occurring in the HKH and adjacent regions. Our work demonstrates that extensive sampling combined with the analysis of diverse data sets can reliably address the taxonomy of morphologically challenging plant taxa. PMID:23056501

Chronic Invasive Fungal Sinusitis Presenting as Inferior Altitudinal Visual Field Defect.

PubMed

Bansal, Reema; Takkar, Aastha; Lal, Vivek; Bal, Amanjit; Bansal, Sandeep

2017-06-01

A young male with acute blurring of vision (6/9) complained of an inferior altitudinal field defect in right eye. Clinical ophthalmological examination was normal. Magnetic resonance imaging (MRI) of the brain revealed the expansion and mucosal thickening of right posterior ethmoid and sphenoid sinuses and opacified right maxillary sinus. Surgical intervention (transethmoidal sphenoidotomy) and histopathological examination revealed chronic invasive granulomatous fungal sinusitis. Anti-fungal therapy led to resolution of visual complaints and restoration of visual field defects.

Sampling high-altitude and stratified mating flights of red imported fire ant.

PubMed

Fritz, Gary N; Fritz, Ann H; Vander Meer, Robert K

2011-05-01

With the exception of an airplane equipped with nets, no method has been developed that successfully samples red imported fire ant, Solenopsis invicta Buren, sexuals in mating/dispersal flights throughout their potential altitudinal trajectories. We developed and tested a method for sampling queens and males during mating flights at altitudinal intervals reaching as high as "140 m. Our trapping system uses an electric winch and a 1.2-m spindle bolted to a swiveling platform. The winch dispenses up to 183 m of Kevlar-core, nylon rope and the spindle stores 10 panels (0.9 by 4.6 m each) of nylon tulle impregnated with Tangle-Trap. The panels can be attached to the rope at various intervals and hoisted into the air by using a 3-m-diameter, helium-filled balloon. Raising or lowering all 10 panels takes approximately 15-20 min. This trap also should be useful for altitudinal sampling of other insects of medical importance.

Newly discovered populations of the Ethiopian endemic and endangered Afrixalus clarkei Largen, implications for conservation.

PubMed

Mertens, Jan; Jocqué, Merlijn; Geeraert, Lore; Beenhouwer, Matthias De

2016-01-01

Knowledge of the Ethiopian amphibian fauna is limited and Southwest Ethiopia remains understudied. This part of Ethiopia, where most of the country's remaining natural forest is situated, is known to harbour the only populations of Afrixalus clarkei (Largen), an endemic banana frog, worldwide. This species is under great threat of extinction and is therefore classified as endangered on the IUCN red list. We surveyed different potential habitats for this species outside its known range and found several new populations extending its known habitat preference, and the geographical and altitudinal range of the species. We here show that Afrixalus clarkei is more common than previously thought.

Phylogenetic inferences of Nepenthes species in Peninsular Malaysia revealed by chloroplast (trnL intron) and nuclear (ITS) DNA sequences.

PubMed

Bunawan, Hamidun; Yen, Choong Chee; Yaakop, Salmah; Noor, Normah Mohd

2017-01-26

The chloroplastic trnL intron and the nuclear internal transcribed spacer (ITS) region were sequenced for 11 Nepenthes species recorded in Peninsular Malaysia to examine their phylogenetic relationship and to evaluate the usage of trnL intron and ITS sequences for phylogenetic reconstruction of this genus. Phylogeny reconstruction was carried out using neighbor-joining, maximum parsimony and Bayesian analyses. All the trees revealed two major clusters, a lowland group consisting of N. ampullaria, N. mirabilis, N. gracilis and N. rafflesiana, and another containing both intermediately distributed species (N. albomarginata and N. benstonei) and four highland species (N. sanguinea, N. macfarlanei, N. ramispina and N. alba). The trnL intron and ITS sequences proved to provide phylogenetic informative characters for deriving a phylogeny of Nepenthes species in Peninsular Malaysia. To our knowledge, this is the first molecular phylogenetic study of Nepenthes species occurring along an altitudinal gradient in Peninsular Malaysia.

Seasonal variations in body melanism and size of the wolf spider Pardosa astrigera (Araneae: Lycosidae).

PubMed

Yang, Jinjian; Wu, Qijia; Xiao, Rong; Zhao, Jupeng; Chen, Jian; Jiao, Xiaoguo

2018-04-01

Variations in species morphology and life-history traits strongly correlate with geographic and climatic characteristics. Most studies on morphological variations in animals focus on ectotherms distributed on a large geographic scale across latitudinal and/or altitudinal gradient. However, the morphological variations of spiders living in the same habitats across different seasons have not been reported. In this study, we used the wolf spider, Pardosa astrigera , as a model to determine seasonal differences in adult body size, melanism, fecundity, and egg diameter both in the overwintering and the first generation for 2010 and 2016. The results showed that in 2010, both females and males of the overwintering generation were significantly darker than the first generation. Moreover, the overwintering females were markedly larger and produced more and bigger eggs than the first generation in both 2010 and 2016. Considering the overwintering P. astrigera experiencing low temperature and/or desiccation stress, these results suggest that substantially darker and larger body of the overwintering generation is adaptive to adverse conditions.

Hydrothermal extremes at the South-West Pribaikalie during the current climate changes

NASA Astrophysics Data System (ADS)

Voropay, Nadezhda

2017-04-01

Climatic extremes of air temperature and precipitation were analyzed for the Tunka Intermountain Depression (South-West Pribaikalie, Buryatia, Russian Federation). Intermountain depressions occupy a quarter of the territory of the Baikal region. The specific climatic conditions in the depressions are formed due to the geographic location and the influence of latitudinal zonation and altitudinal gradients. Air temperature and precipitation data records from at weather stations for the period 1940-2015 were analyzed. Long-term average annual temperature is negative and varies from -0.8 °C to -2.4 °C. Air temperature absolute minimum is -48 °C, absolute maximum is +36 °C. The long-term average annual precipitation is 370-480 mm, but in some years annual precipitation reach 760 mm. The summer months have about 70% of the total annual precipitation, in July and August the sum may reach 340 mm. Maximum daily sum of rainfalls is 80 mm. The contribution of the global and regional circulation characteristics into the variability of regional climatic characteristics was estimated.

Sustainable utilization and conservation of plant biodiversity in montane ecosystems: the western Himalayas as a case study.

PubMed

Khan, Shujaul Mulk; Page, Sue E; Ahmad, Habib; Harper, David M

2013-08-01

Conservation of the unique biodiversity of mountain ecosystems needs trans-disciplinary approaches to succeed in a crowded colloquial world. Geographers, conservationists, ecologists and social scientists have, in the past, had the same conservation goals but have tended to work independently. In this review, the need to integrate different conservation criteria and methodologies is discussed. New criteria are offered for prioritizing species and habitats for conservation in montane ecosystems that combine both ecological and social data. Ecological attributes of plant species, analysed through robust community statistical packages, provide unbiased classifications of species assemblages and environmental biodiversity gradients and yield importance value indices (IVIs). Surveys of local communities' utilization of the vegetation provides use values (UVs). This review suggests a new means of assessing anthropogenic pressure on plant biodiversity at both species and community levels by integrating IVI and UV data sets in a combined analysis. Mountain ecosystems are hot spots for plant conservation efforts because they hold a high overall plant diversity as communities replace each other along altitudinal and climatic gradients, including a high proportion of endemic species. This review contributes an enhanced understanding of (1) plant diversity in mountain ecosystems with special reference to the western Himalayas; (2) ethnobotanical and ecosystem service values of mountain vegetation within the context of anthropogenic impacts; and (3) local and regional plant conservation strategies and priorities.

Climatically driven yield variability of major crops in Khakassia (South Siberia)

NASA Astrophysics Data System (ADS)

Babushkina, Elena A.; Belokopytova, Liliana V.; Zhirnova, Dina F.; Shah, Santosh K.; Kostyakova, Tatiana V.

2018-06-01

We investigated the variability of yield of the three main crop cultures in the Khakassia Republic: spring wheat, spring barley, and oats. In terms of yield values, variability characteristics, and climatic response, the agricultural territory of Khakassia can be divided into three zones: (1) the Northern Zone, where crops yield has a high positive response to the amount of precipitation, May-July, and a moderately negative one to the temperatures of the same period; (2) the Central Zone, where crops yield depends mainly on temperatures; and (3) the Southern Zone, where climate has the least expressed impact on yield. The dominant pattern in the crops yield is caused by water stress during periods of high temperatures and low moisture supply with heat stress as additional reason. Differences between zones are due to combinations of temperature latitudinal gradient, precipitation altitudinal gradient, and the presence of a well-developed hydrological network and the irrigational system as moisture sources in the Central Zone. More detailed analysis shows differences in the climatic sensitivity of crops during phases of their vegetative growth and grain development and, to a lesser extent, during harvesting period. Multifactor linear regression models were constructed to estimate climate- and autocorrelation-induced variability of the crops yield. These models allowed prediction of the possibility of yield decreasing by at least 2-11% in the next decade due to increasing of the regional summer temperatures.

Sustainable utilization and conservation of plant biodiversity in montane ecosystems: the western Himalayas as a case study

PubMed Central

Khan, Shujaul Mulk; Page, Sue E.; Ahmad, Habib; Harper, David M.

2013-01-01

Background Conservation of the unique biodiversity of mountain ecosystems needs trans-disciplinary approaches to succeed in a crowded colloquial world. Geographers, conservationists, ecologists and social scientists have, in the past, had the same conservation goals but have tended to work independently. In this review, the need to integrate different conservation criteria and methodologies is discussed. New criteria are offered for prioritizing species and habitats for conservation in montane ecosystems that combine both ecological and social data. Scope Ecological attributes of plant species, analysed through robust community statistical packages, provide unbiased classifications of species assemblages and environmental biodiversity gradients and yield importance value indices (IVIs). Surveys of local communities’ utilization of the vegetation provides use values (UVs). This review suggests a new means of assessing anthropogenic pressure on plant biodiversity at both species and community levels by integrating IVI and UV data sets in a combined analysis. Conclusions Mountain ecosystems are hot spots for plant conservation efforts because they hold a high overall plant diversity as communities replace each other along altitudinal and climatic gradients, including a high proportion of endemic species. This review contributes an enhanced understanding of (1) plant diversity in mountain ecosystems with special reference to the western Himalayas; (2) ethnobotanical and ecosystem service values of mountain vegetation within the context of anthropogenic impacts; and (3) local and regional plant conservation strategies and priorities. PMID:23825353

Climatically driven yield variability of major crops in Khakassia (South Siberia)

NASA Astrophysics Data System (ADS)

Babushkina, Elena A.; Belokopytova, Liliana V.; Zhirnova, Dina F.; Shah, Santosh K.; Kostyakova, Tatiana V.

2017-12-01

We investigated the variability of yield of the three main crop cultures in the Khakassia Republic: spring wheat, spring barley, and oats. In terms of yield values, variability characteristics, and climatic response, the agricultural territory of Khakassia can be divided into three zones: (1) the Northern Zone, where crops yield has a high positive response to the amount of precipitation, May-July, and a moderately negative one to the temperatures of the same period; (2) the Central Zone, where crops yield depends mainly on temperatures; and (3) the Southern Zone, where climate has the least expressed impact on yield. The dominant pattern in the crops yield is caused by water stress during periods of high temperatures and low moisture supply with heat stress as additional reason. Differences between zones are due to combinations of temperature latitudinal gradient, precipitation altitudinal gradient, and the presence of a well-developed hydrological network and the irrigational system as moisture sources in the Central Zone. More detailed analysis shows differences in the climatic sensitivity of crops during phases of their vegetative growth and grain development and, to a lesser extent, during harvesting period. Multifactor linear regression models were constructed to estimate climate- and autocorrelation-induced variability of the crops yield. These models allowed prediction of the possibility of yield decreasing by at least 2-11% in the next decade due to increasing of the regional summer temperatures.

Dynamic and inertial controls on forest carbon-water relations

NASA Astrophysics Data System (ADS)

Maxwell, T.; Silva, L.; Horwath, W. R.

2017-12-01

This study fuses theory, empirical measurements, and statistical models to evaluate multiple processes controlling coupled carbon-water cycles in forest ecosystems. A series of latitudinal and altitudinal transects across the California Sierra Nevada was used to study the effects of climatic and edaphic gradients on intrinsic water-use efficiency (iWUE) - CO2 fixed per unit of water lost via transpiration - of nine dominant trees species. Transfer functions were determined between leaf, litter, and soil organic matter stable isotope ratios of carbon, oxygen, and nitrogen, revealing causal links between the physiological performance of tree species and stand-level estimations of productivity and water balance. Our results show that species iWUE is governed both by leaf traits (24% of the variation) and edaphic properties, such as parent material and soil development (3% and 12% of the variation, respectively). We show that soil properties combined with isotopic indicators can be used to explain constraints over iWUE by regulating water and nutrient availability across elevation gradients. Based on observed compositional shifts likely driven by changing climates in the region, encroachment of broad leaf trees could lead to an 80% increase in water loss via transpiration for each unit of CO2 fixed in Sierra mixed conifer zones. A combination of field-based, laboratory, and remote sensed data provide a useful framework for differentiating the effect of multiple controls of carbon and water cycles in temperate forest ecosystems.

Humic Acid Composition and Characteristics of Soil Organic Matter in Relation to the Elevation Gradient of Moso Bamboo Plantations.

PubMed

Wang, Hsueh-Ching; Chou, Chiao-Ying; Chiou, Chyi-Rong; Tian, Guanglong; Chiu, Chih-Yu

2016-01-01

Studying the influence of climatic and/or site-specific factors on soil organic matter (SOM) along an elevation gradient is important for understanding the response of SOM to global warming. We evaluated the composition of SOM and structure of humic acids along an altitudinal gradient from 600 to 1400 m in moso bamboo (Phyllostachys edulis) plantations in central Taiwan using NMR spectroscopy and photometric analysis. Total organic C and total nitrogen (N) content increased with increasing elevation. Aromaticity decreased and ΔlogK (the logarithm of the absorbance ratio of humic acids at 400 and 600 nm) increased with increasing elevation, which suggests that SOM humification decreased with increasing elevation. High temperature at low elevations seemed to enhance the decomposition (less accumulation of total organic C and N) and humification (high aromaticity and low ΔlogK). The alkyl-C/O-alkyl-C (A/O-A) ratio of humic acids increased with increasing elevation, which suggests that SOM humification increased with increasing elevation; this finding was contrary to the trend observed for ΔlogK and aromaticity. Such a discrepancy might be due to the relatively greater remaining of SOM derived from high alkyl-C broadleaf litter of previous forest at high elevations. The ratio of recalcitrant C to total organic C was low at low elevations, possibly because of enhanced decomposition of recalcitrant SOM from the previous broadleaf forest during long-term intensive cultivation and high temperature. Overall, the change in SOM pools and in the rate of humification with elevation was primarily affected by changes in climatic conditions along the elevation gradient in these bamboo plantations. However, when the composition of SOM, as assessed by NMR spectroscopy and photometric analysis was considered, site-specific factors such as residual SOM from previous forest and intensive cultivation history could also have an important effect on the humic acid composition and humification of SOM.

Humic Acid Composition and Characteristics of Soil Organic Matter in Relation to the Elevation Gradient of Moso Bamboo Plantations

PubMed Central

Wang, Hsueh-Ching; Chou, Chiao-Ying; Chiou, Chyi-Rong; Tian, Guanglong

2016-01-01

Studying the influence of climatic and/or site-specific factors on soil organic matter (SOM) along an elevation gradient is important for understanding the response of SOM to global warming. We evaluated the composition of SOM and structure of humic acids along an altitudinal gradient from 600 to 1400 m in moso bamboo (Phyllostachys edulis) plantations in central Taiwan using NMR spectroscopy and photometric analysis. Total organic C and total nitrogen (N) content increased with increasing elevation. Aromaticity decreased and ΔlogK (the logarithm of the absorbance ratio of humic acids at 400 and 600 nm) increased with increasing elevation, which suggests that SOM humification decreased with increasing elevation. High temperature at low elevations seemed to enhance the decomposition (less accumulation of total organic C and N) and humification (high aromaticity and low ΔlogK). The alkyl-C/O-alkyl-C (A/O-A) ratio of humic acids increased with increasing elevation, which suggests that SOM humification increased with increasing elevation; this finding was contrary to the trend observed for ΔlogK and aromaticity. Such a discrepancy might be due to the relatively greater remaining of SOM derived from high alkyl-C broadleaf litter of previous forest at high elevations. The ratio of recalcitrant C to total organic C was low at low elevations, possibly because of enhanced decomposition of recalcitrant SOM from the previous broadleaf forest during long-term intensive cultivation and high temperature. Overall, the change in SOM pools and in the rate of humification with elevation was primarily affected by changes in climatic conditions along the elevation gradient in these bamboo plantations. However, when the composition of SOM, as assessed by NMR spectroscopy and photometric analysis was considered, site-specific factors such as residual SOM from previous forest and intensive cultivation history could also have an important effect on the humic acid composition and humification of SOM. PMID:27583451

A spatial implementation of the BIOME-BGC to model grassland GPP production and water budgets in the Ecuadorian Andean Region

NASA Astrophysics Data System (ADS)

Minaya, Veronica; Corzo, Gerald; van der Kwast, Johannes; Mynett, Arthur

2016-04-01

Many terrestrial biogeochemistry process models have been applied around the world at different scales and for a large range of ecosystems. Grasslands, and in particular the ones located in the Andean Region are essential ecosystems that sustain important ecological processes; however, just a few efforts have been made to estimate the gross primary production (GPP) and the hydrological budgets for this specific ecosystem along an altitudinal gradient. A previous study, which is one of the few available in the region, considered the heterogeneity of the main properties of the páramo vegetation and showed significant differences in plant functional types, site/soil parameters and daily meteorology. This study extends the work above mentioned and uses spatio-temporal analysis of the BIOME-BGC model results. This was done to simulate the GPP and the water fluxes in space and time, by applying altitudinal analysis. The catchment located at the southwestern slope of the Antisana volcano in Ecuador was selected as a representative area of the Andean páramos and its hydrological importance as one of the main sources of a water supply reservoir in the region. An accurate estimation of temporal changes in GPP in the region is important for carbon budget assessments, evaluation of the impact of climate change and biomass productivity. This complex and yet interesting problem was integrated by the ecosystem process model BIOME-BGC, the results were evaluated and associated to the land cover map where the growth forms of vegetation were identified. The responses of GPP and the water fluxes were not only dependent on the environmental drivers but also on the ecophysiology and the site specific parameters. The model estimated that the GPP at lower elevations doubles the amount estimated at higher elevations, which might have a large implication during extrapolations at larger spatio-temporal scales. The outcomes of the stand hydrological processes demonstrated a wrong consideration of a unique input of water in the system in addition to the poor estimation of the water storage leading to a wrong assessment of the water fluxes in the páramo ecosystem. A further development of the BIOME-BGC is needed to be applicable in the spatio-temporal analysis of the páramo vegetation in the region that can potentially assess the changes in the terrestrial ecosystem due to variations in the climatic drivers.

Transplantation of subalpine wood-pasture turfs along a natural climatic gradient reveals lower resistance of unwooded pastures to climate change compared to wooded ones.

PubMed

Gavazov, Konstantin; Spiegelberger, Thomas; Buttler, Alexandre

2014-04-01

Climate change could impact strongly on cold-adapted mountain ecosystems, but little is known about its interaction with traditional land-use practices. We used an altitudinal gradient to simulate a year-round warmer and drier climate for semi-natural subalpine grasslands across a landscape of contrasting land-use management. Turf mesocosms from three pasture-woodland land-use types-unwooded pasture, sparsely wooded pasture, and densely wooded pasture-spanning a gradient from high to low management intensity were transplanted downslope to test their resistance to two intensities of climate change. We found strong overall effects of intensive (+4 K) experimental climate change (i.e., warming and reduced precipitation) on plant community structure and function, while moderate (+2 K) climate change did not substantially affect the studied land-use types, thus indicating an ecosystem response threshold to moderate climate perturbation. The individual land-use types were affected differently under the +4 K scenario, with a 60% decrease in aboveground biomass (AGB) in unwooded pasture turfs, a 40% decrease in sparsely wooded pasture turfs, and none in densely wooded ones. Similarly, unwooded pasture turfs experienced a 30% loss of species, advanced (by 30 days) phenological development, and a mid-season senescence due to drought stress, while no such effects were recorded for the other land-use types. The observed contrasting effects of climate change across the pasture-woodland landscape have important implications for future decades. The reduced impact of climate change on wooded pastures as compared to unwooded ones should promote the sustainable land use of wooded pastures by maintaining low management intensity and a sparse forest canopy, which buffer the immediate impacts of climate change on herbaceous vegetation.

Comparing the response of birds and butterflies to vegetation-based mountain ecotones using boundary detection approaches.

PubMed

Kent, Rafi; Levanoni, Oded; Banker, Eran; Pe'er, Guy; Kark, Salit

2013-01-01

Mountains provide an opportunity to examine changes in biodiversity across environmental gradients and areas of transition (ecotones). Mountain ecotones separate vegetation belts. Here, we aimed to examine whether transition areas for birds and butterflies spatially correspond with ecotones between three previously described altitudinal vegetation belts on Mt. Hermon, northern Israel. These include the Mediterranean Maquis, xero-montane open forest and Tragacanthic mountain steppe vegetation belts. We sampled the abundance of bird and butterfly species in 34 sampling locations along an elevational gradient between 500 and 2200 m. We applied wombling, a boundary-detection technique, which detects rapid changes in a continuous variable, in order to locate the transition areas for bird and butterfly communities and compare the location of these areas with the location of vegetation belts as described in earlier studies of Mt. Hermon. We found some correspondence between the areas of transition of both bird and butterfly communities and the ecotones between vegetation belts. For birds and butterflies, important transitions occurred at the lower vegetation ecotone between Mediterranean maquis and the xero-montane open forest vegetation belts, and between the xero-montane open forest and the mountain steppe Tragacanthic belts. While patterns of species turnover with elevation were similar for birds and butterflies, the change in species richness and diversity with elevation differed substantially between the two taxa. Birds and butterflies responded quite similarly to the elevational gradient and to the shift between vegetation belts in terms of species turnover rates. While the mechanisms generating these patterns may differ, the resulting areas of peak turnover in species show correspondence among three different taxa (plants, birds and butterflies).

Projecting the Local Impacts of Climate Change on a Central American Montane Avian Community

NASA Technical Reports Server (NTRS)

Gasner, Matthew R.; Jankowski, Jill E.; Ciecka, Anna L.; Kyle, Keiller O.; Rabenold, Kerry N.

2010-01-01

Significant changes in the climates of Central America are expected over the next century. Lowland rainforests harbor high alpha diversity on local scales (<1 km2), yet montane landscapes often support higher beta diversity on 10-100 km2 scales. Climate change will likely disrupt the altitudinal zonation of montane communities that produces such landscape diversity. Projections of biotic response to climate change have often used broad-scale modelling of geographical ranges, but understanding likely impacts on population viability is also necessary for anticipating local and global extinctions. We model species abundances and estimate range shifts for birds in the Tilaran Mountains of Costa Rica, asking whether projected changes in temperature and rainfall could be sufficient to imperil high-elevation endemics and whether these variables will likely impact communities similarly. We find that nearly half of 77 forest bird species can be expected to decline in the next century. Almost half of species projected to decline are endemic to Central America, and seven of eight species projected to become locally extinct are endemic to the highlands of Costa Rica and Panam . Logistic-regression modelling of distributions and similarity in projections produced by temperature and rainfall models suggest that changes in both variables will be important. Although these projections are probably conservative because they do not explicitly incorporate biological or climate variable interactions, they provide a starting point for incorporating more realistic biological complexity into community-change models. Prudent conservation planning for tropical mountains should focus on regions with room for altitudinal reorganization of communities comprised of ecological specialists.

The role of metabolism in understanding the altitudinal segregation pattern of two potentially interacting lizards.

PubMed

Žagar, Anamarija; Simčič, Tatjana; Carretero, Miguel A; Vrezec, Al

2015-01-01

Sympatric species from the same ecological guild, that exhibit partial altitudinal segregation, can potentially interact in areas of syntopic occurrence. Besides general species' ecology, physiology can provide important answers about species interactions reflected in altitudinal patterns. Lizards Podarcis muralis and Iberolacerta horvathi exhibit partial altitudinal segregation, while they strongly resemble in overall morphology and ecology (diet, daily and seasonal activity pattern), but show certain degree of physiological dissimilarity. They have similar mean preferred body temperatures and patterns of seasonal and daily variations but differ in the magnitude of seasonal variation. Since an ectotherm metabolism is highly dependent on body temperature, thermoregulation is expected to directly affect their metabolism. We compared metabolic rates of adult males from an area of sympatry, measured under two temperature regimes (20°C and 28°C). Both species increased metabolic rates with temperature in a similar pattern. We also compared electron transport activity from tail tissues which provide values of species' potential metabolic activity (enzymatic capacity). Species clearly differed in potential metabolic activity; I. horvathi attained higher values than P. muralis. No difference was detected in how species exploited this potential (calculated from the ratio of electron transport activity and metabolic rates). However, we observed higher potential metabolic activity I. horvathi which together with the ability to thermoregulate more precisely could represent a higher competitive advantage over P. muralis in thermally more restrictive environments such as higher altitudes. Understanding of metabolism seems to provide valuable information for understanding recent distributional patterns as well as species interactions. Copyright © 2014 Elsevier Inc. All rights reserved.

Integrating evolutionary and functional tests of adaptive hypotheses: a case study of altitudinal differentiation in hemoglobin function in an Andean Sparrow, Zonotrichia capensis.

PubMed

Cheviron, Zachary A; Natarajan, Chandrasekhar; Projecto-Garcia, Joana; Eddy, Douglas K; Jones, Jennifer; Carling, Matthew D; Witt, Christopher C; Moriyama, Hideaki; Weber, Roy E; Fago, Angela; Storz, Jay F

2014-11-01

In air-breathing vertebrates, the physiologically optimal blood-O2 affinity is jointly determined by the prevailing partial pressure of atmospheric O2, the efficacy of pulmonary O2 transfer, and internal metabolic demands. Consequently, genetic variation in the oxygenation properties of hemoglobin (Hb) may be subject to spatially varying selection in species with broad elevational distributions. Here we report the results of a combined functional and evolutionary analysis of Hb polymorphism in the rufous-collared sparrow (Zonotrichia capensis), a species that is continuously distributed across a steep elevational gradient on the Pacific slope of the Peruvian Andes. We integrated a population genomic analysis that included all postnatally expressed Hb genes with functional studies of naturally occurring Hb variants, as well as recombinant Hb (rHb) mutants that were engineered through site-directed mutagenesis. We identified three clinally varying amino acid polymorphisms: Two in the α(A)-globin gene, which encodes the α-chain subunits of the major HbA isoform, and one in the α(D)-globin gene, which encodes the α-chain subunits of the minor HbD isoform. We then constructed and experimentally tested single- and double-mutant rHbs representing each of the alternative α(A)-globin genotypes that predominate at different elevations. Although the locus-specific patterns of altitudinal differentiation suggested a history of spatially varying selection acting on Hb polymorphism, the experimental tests demonstrated that the observed amino acid mutations have no discernible effect on respiratory properties of the HbA or HbD isoforms. These results highlight the importance of experimentally validating the hypothesized effects of genetic changes in protein function to avoid the pitfalls of adaptive storytelling. © The Author 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Human onchocerciasis in the Amazonian area of southern Venezuela: spatial and temporal variations in biting and parity rates of black fly (Diptera: Simuliidae) vectors.

PubMed

Grillet, M E; Basáñez, M G; Vivas-Martínez, S; Villamizar, N; Frontado, H; Cortez, J; Coronel, P; Botto, C

2001-07-01

We investigated some entomological factors underlying altitudinal prevalence variation in the Venezuelan Amazonia human onchocerciasis focus. Spatial and temporal variation in relative abundance, daily biting rate, proportion of parous flies, and monthly parous biting rate were studied for the three main simuliid vectors (based on their vectorial competence: Simulium oyapockense s.l. Floch & Abonnenc approximately = S. incrustatum Lutz < S. guianense s.l. Wise). Yanomami villages were selected among sentinel communities of the ivermectin control program, representing hypo- to hyperendemicity conditions of infection. Spatial variation was explored via increasing village altitude on two river systems (A: Ocamo-Putaco and B: Orinoco-Orinoquito). Temporal variation was studied between 1995 and 1999 by sampling the biting population during dry and rainy mouths. Environmental variables included monthly rainfall and maximum river height. Simuliid species composition itself varied along the altitudinal and prevalence gradient. S. oyapockense s.l. prevailed below 150 m. Above this altitude and up to 240 m, S. incrustatum and S. guianense s.l. became more frequently and evenly collected along A but not along B, where S. incrustatum remained absent. The daily biting rate of S. oyapockense s.l. was higher during the dry season along A, whereas the converse took place along B. Daily biting rate of S. incrustatum was lowest during early rains. By contrast, the daily biting rate of S. guianense s.l. was highest during this period. There was a significant negative cross-correlation between proportion of parous of S. oyapockense s.l. and river height (2 and 3 mo lagged), whereas this variable (1 and 2 mo lagged) was positively correlated with the proportion of parous flies for S. incrustatum. Monthly parous biting rate values suggest that the months contributing most to onchocerciasis transmission in the area are likely to be the dry season and the transition periods between seasons.

Altitudinal variations of ground tissue and xylem tissue in terminal shoot of woody species: implications for treeline formation.

PubMed

Chen, Hong; Wang, Haiyang; Liu, Yanfang; Dong, Li

2013-01-01

1. The terminal shoot (or current-year shoot), as one of the most active parts on a woody plant, is a basic unit determining plant height and is potentially influenced by a variety of environmental factors. It has been predicted that tissues amount and their allocation in plant stems may play a critical role in determining plant size in alpine regions. The primary structure in terminal shoots is a key to our understanding treeline formation. The existing theories on treeline formation, however, are still largely lacking of evidence at the species level, much less from anatomy for the terminal shoot. 2. The primary structures within terminal shoot were measured quantitatively for 100 species from four elevation zones along the eastern slope of Gongga Mountain, southwestern China; one group was sampled from above the treeline. An allometric approach was employed to examine scaling relationships interspecifically, and a principal components analysis (PCA) was performed to test the relation among primary xylem, ground tissue, species growth form and altitude. 3. The results showed that xylem tissue size was closely correlated with ground tissue size isometrically across species, while undergoing significant y- or/and x-intercept shift in response to altitudinal belts. Further, a conspicuous characteristic of terminal shoot was its allocation of contrasting tissues between primary xylem and ground tissues with increasing elevation. The result of the PCA showed correlations between anatomical variation, species growth form/height classes and environment. 4. The current study presents a comparative assessment of the allocation of tissue in terminal shoot across phylogenically and ecologically diverse species, and analyzes tissue, function and climate associations with plant growth forms and height classes among species. The interspecific connection between primary xylem ratio and plant size along an elevation gradient suggests the importance of primary xylem in explaining the treeline formation.

Altitudinal Variations of Ground Tissue and Xylem Tissue in Terminal Shoot of Woody Species: Implications for Treeline Formation

PubMed Central

Chen, Hong; Wang, Haiyang; Liu, Yanfang; Dong, Li

2013-01-01

1. The terminal shoot (or current-year shoot), as one of the most active parts on a woody plant, is a basic unit determining plant height and is potentially influenced by a variety of environmental factors. It has been predicted that tissues amount and their allocation in plant stems may play a critical role in determining plant size in alpine regions. The primary structure in terminal shoots is a key to our understanding treeline formation. The existing theories on treeline formation, however, are still largely lacking of evidence at the species level, much less from anatomy for the terminal shoot. 2. The primary structures within terminal shoot were measured quantitatively for 100 species from four elevation zones along the eastern slope of Gongga Mountain, southwestern China; one group was sampled from above the treeline. An allometric approach was employed to examine scaling relationships interspecifically, and a principal components analysis (PCA) was performed to test the relation among primary xylem, ground tissue, species growth form and altitude. 3. The results showed that xylem tissue size was closely correlated with ground tissue size isometrically across species, while undergoing significant y- or/and x-intercept shift in response to altitudinal belts. Further, a conspicuous characteristic of terminal shoot was its allocation of contrasting tissues between primary xylem and ground tissues with increasing elevation. The result of the PCA showed correlations between anatomical variation, species growth form/height classes and environment. 4. The current study presents a comparative assessment of the allocation of tissue in terminal shoot across phylogenically and ecologically diverse species, and analyzes tissue, function and climate associations with plant growth forms and height classes among species. The interspecific connection between primary xylem ratio and plant size along an elevation gradient suggests the importance of primary xylem in explaining the treeline formation. PMID:23658621

Interspecific Competition and Trade-offs in Resource Allocation are the Key to Successful Growth of Seedlings of White Spruce (Picea glauca (Moench) Voss) at Subarctic Treelines in Warming Alaska.

NASA Astrophysics Data System (ADS)

Okano, K.; Bret-Harte, M. S.

2015-12-01

Alpine treelines in Alaska have advanced for the past 50 years in response to the recent climate warming. However, further increases in temperatures may cause treeline species drought stress and increase susceptibility to insect outbreaks and fire. Complex factors such as soil conditions and plant species composition also impact the growth of seedlings, which are essential to sustain boreal forests. Our goals were to assess 1) the current optimal elevation for the treeline species Picea glauca (white spruce) seedlings and how it is altered by climate change, and 2) their growth/survival strategies at each environmental site. We studied the growth response of spruce seedlings along an altitudinal gradient at 6 sites, consisting of tundra, forest, or transitional ecotone in Denali National Park and one forest site in Fairbanks, AK. In May 2012, four-month old seedlings were planted with or without naturally occurring plants to compare the presence or absence of the interspecific interaction. Summer temperatures were increased by one small greenhouse per site. Over 2 growing seasons, growth was measured non-destructively, and then the seedlings were harvested. Relative growth rate (RGR) in height was increased significantly as the altitude was increased. Elevated temperature increased height only in seedlings at a high-altitude forest. Seedlings with neighboring plants had a higher RGR in height than seedlings that had neighbors removed, while significantly wider diameters were measured from the seedlings without neighbors. A weak trend of declining diameter width with increasing altitudes was seen. Seedlings that grew taller did not grow their stems wider, indicating trade-offs in resource allocation. None of the altitudinal sites had a clear advantage for the growth of the seedlings. Habitat microclimate and the interaction with other species could be more important than the altitude or temperatures and hence, key to the survival and growth of spruce seedlings in this region.

Impact of topography, climate and moisture sources on isotopic composition (δ18O &δD) of rivers in the Pyrenees: Implications for topographic reconstructions in small orogens

NASA Astrophysics Data System (ADS)

Huyghe, Damien; Mouthereau, Frédéric; Sébilo, Mathieu; Vacherat, Arnaud; Ségalen, Loïc; Richard, Patricia; Biron, Philippe; Bariac, Thierry

2018-02-01

Understanding how orogenic topography controls the spatial distribution and isotopic composition of precipitation is critical for paleoaltitudinal reconstructions. Here, we determine the isotopic composition (δ18O and δD) of 82 small rivers and springs from small catchments in the Pyrenees. Calculation of the deuterium excess (d-excess) parameter allows the distinction of four distinct isotopic provinces with d-excess values of between 15 and 22‰ in the northwest, between 7 and 14‰ in the central northern Pyrenees and between 3 and 11‰ in the northeast. The southern Pyrenees have a homogenous d-excess signature ranging from 7 to 14‰. Our results show significant local moisture recycling and/or rain amount effect in the northwestern Pyrenees, and control by evaporation processes during rainfall events in the southern Pyrenees and for low elevated samples of the northeast of the range. Based on the distribution of d-excess values, we estimate contrasting isotope lapse rates of -2.9/-21.4‰/km (δ18O/δD) in the northwest, -2.7/-21.4‰/km (δ18O/δD) in the north central and -3.7/-31.7‰/km (δ18O/δD) in the northeastern Pyrenees. The southern Pyrenees show distinctly higher lapse rates of -9.5/-77.5‰/km (δ18O/δD), indicating that in this area the altitudinal effect in not the only parameter driving isotopic composition of rivers. Despite their relatively low topographic gradient, the Pyrenees exert a direct control on the isotopic composition of river waters, especially on their northern side. The variations in isotopic composition-elevation relationships documented along the strike of the range are interpreted to reflect an increasing continentality effect driven by wind trajectories parallel to the range, and mixing with Mediterranean air masses. Despite these effects, the measurable orographic effect on precipitation in the Pyrenees proves that the isotopic composition approach for reconstructing past topography is applicable to low-elevation orogens.

Effects of climate and geochemistry on soil organic matter stabilization and greenhouse gas emissions along altitudinal transects in different mountain regions

NASA Astrophysics Data System (ADS)

Griepentrog, Marco; Bodé, Samuel; Boudin, Mathieu; Dercon, Gerd; Doetterl, Sebastian; Matulanya, Machibya; Msigwa, Anna; Vermeir, Pieter; Boeckx, Pascal

2017-04-01

Terrestrial ecosystems are strongly influenced by climate change and soils are key compartments of the global carbon (C) cycle in terms of their potential to store or release significant amounts of C. This study is part of the interregional IAEA Technical Cooperation Project ``Assessing the Impact of Climate Change and its Effects on Soil and Water Resources in Polar and Mountainous Regions (INT5153)'' aiming to improve the understanding of climate change impacts on soil organic carbon (SOC) in fragile polar and high mountainous ecosystems at local and global scale for their better management and conservation. The project includes 13 benchmark sites situated around the world. Here we present novel data from altitudinal transects of three different mountain regions (Mount Kilimanjaro, Tanzania; Mount Gongga, China; Cordillera Blanca, Peru). All altitudinal transects cover a wide range of natural ecosystems under different climates and soil geochemistry. Bulk soil samples (four field replicates per ecosystem) were subjected to a combination of aggregate and particle-size fractionation followed by organic C, total nitrogen, stable isotope (13C, 15N) and radiocarbon (14C) analyses of all fractions. Bulk soils were further characterized for their geochemistry (Na, K, Ca, Mg, Al, Fe, Mn, Si, P) and incubated for 63 days to assess greenhouse gas emissions (CO2, CH4, NO, N2O). Further, stable C isotopic signature of CO2 was measured to determine the isotopic signature of soil respiration (using Keeling plots) and to estimate potential respiration sources. The following four ecosystems were sampled at an altitudinal transect on the (wet) southern slopes of Mount Kilimanjaro: savannah (920m), lower montane rain forests with angiosperm trees (2020m), upper montane cloud forest with gymnosperm trees (2680m), subalpine heathlands (3660m). Both forests showed highest C contents followed by subalpine and savannah. The largest part of SOC was found in particulate organic matter followed by microaggregates, except for the subalpine ecosystem which had most SOC stored in microaggregates. Silt and clay fractions stored the smallest fraction of SOC for all ecosystems. Cumulative soil CO2 emissions (normalized to SOC, gCO_2-C kgSOC-1) after 63 days of incubation were highest for savannah (15.2 ± 1.4) followed by subalpine (7.9 ± 0.5), upper forest (6.9 ± 1.0) and lower forest (4.8 ± 0.4). CO2 emissions were negatively correlated with soil C contents, showing that soils with lower C contents loose higher relative amounts of their SOC through soil respiration. Keeling plot intercept is a measure for the isotopic signature of respired CO2 and high offsets between Keeling plot intercepts and the isotopic signature of bulk SOC point towards labile (13C-depleted) SOC fractions as respiration sources. Highest offsets (and thus most labile respiration sources) were observed for savannah followed by subalpine, lower forest and upper forest and these were positively correlated with cumulative CO2 emissions, showing that in savannah soils, which have lowest C contents and respire highest amounts of CO2, mainly labile SOC is used as respiration source. Results from the other two altitudinal transects are currently under investigation and will be presented in conjunction with climatic and geochemical data.

Seasonal distribution and aerial surveys of mountain goats in Mount Rainier, North Cascades, and Olympic National Parks, Washington

USGS Publications Warehouse

Jenkins, Kurt; Beirne, Katherine; Happe, Patricia; Hoffman, Roger; Rice, Cliff; Schaberl, Jim

2011-01-01

We described the seasonal distribution of Geographic Positioning System (GPS)-collared mountain goats (Oreamnos americanus) in Mount Rainier, North Cascades, and Olympic National Parks to evaluate aerial survey sampling designs and provide general information for park managers. This work complemented a companion study published elsewhere of aerial detection biases of mountain goat surveys in western Washington. Specific objectives reported here were to determine seasonal and altitudinal movements, home range distributions, and temporal dynamics of mountain goat movements in and out of aerial survey sampling frames established within each park. We captured 25 mountain goats in Mount Rainier (9), North Cascades (5), and Olympic (11) National Parks, and fitted them with GPS-collars programmed to obtain 6-8 locations daily. We obtained location data on 23 mountain goats for a range of 39-751 days from 2003 to 2008. Altitudinal distributions of GPS-collared mountain goats varied individually and seasonally, but median altitudes used by individual goats during winter ranged from 817 to 1,541 meters in Olympic and North Cascades National Parks, and 1,215 to 1,787 meters in Mount Rainier National Park. Median altitudes used by GPS-collared goats during summer ranged from 1,312 to 1,819 meters in Olympic and North Cascades National Parks, and 1,780 to 2,061 meters in Mount Rainier National Park. GPS-collared mountain goats generally moved from low-altitude winter ranges to high-altitude summer ranges between June 11 and June 19 (range April 24-July 3) and from summer to winter ranges between October 26 and November 9 (range September 11-December 23). Seasonal home ranges (95 percent of adaptive kernel utilization distribution) of males and female mountain goats were highly variable, ranging from 1.6 to 37.0 kilometers during summers and 0.7 to 9.5 kilometers during winters. Locations of GPS-collared mountain goats were almost 100 percent within the sampling frame used for mountain goat surveys in Mount Rainier National Park, whereas generally greater than 80 and greater than 60 percent of locations were within sampling units delineated in North Cascades and Olympic National Parks, respectively. Presence of GPS-collared mountain goats within the sampling frame of Olympic National Park varied by diurnal period (midday versus crepuscular), survey season (July versus September), and the interaction of diurnal period and survey season. Aerial surveys conducted in developing a sightability model for mountain goat aerial surveys indicated mean detection probabilities of 0.69, 0.76, and 0.87 in North Cascades, Olympic, and Mount Rainier National Parks, respectively. Higher detection probabilities in Mount Rainier likely reflected larger group sizes and more open habitat conditions than in North Cascades and Olympic National Parks. Use of sightability models will reduce biases of population estimates in each park, but resulting population estimates must still be considered minimum population estimates in Olympic and North Cascades National Parks because the current sampling frames do not encompass those populations completely. Because mountain goats were reliably present within the sampling frame in Mount Rainier National Park, we found no compelling need to adjust mountain goat survey boundaries in that park. Expanding survey coverage in North Cascades and Olympic National Parks to more reliably encompass the altitudinal distribution of mountain goats during summer would enhance population estimation accuracy in the future. Lowering the altitude boundary of mountain goat survey units by as little as 100 meters to 1,425 meters in Olympic National Park would increase mountain goat presence within the survey and reduce variation in counts related to movements of mountain goats outside the survey boundaries.

Macroecology of unicellular organisms - patterns and processes.

PubMed

Soininen, Janne

2012-02-01

Macroecology examines the relationship between organisms and their environment at large spatial (and temporal) scales. Typically, macroecologists explain the large-scale patterns of abundance, distribution and diversity. Despite the difficulties in sampling and characterizing microbial diversity, macroecologists have recently also been interested in unicellular organisms. Here, I review the current advances made in microbial macroecology, as well as discuss related ecosystem functions. Overall, it seems that microorganisms suit surprisingly well to known species abundance distributions and show positive relationship between distribution and adundance. Microbial species-area and distance-decay relationships tend to be weaker than for macroorganisms, but nonetheless significant. Few findings on altitudinal gradients in unicellular taxa seem to differ greatly from corresponding findings for larger taxa, whereas latitudinal gradients among microorganisms have either been clearly evident or absent depending on the context. Literature also strongly emphasizes the role of spatial scale for the patterns of diversity and suggests that patterns are affected by species traits as well as ecosystem characteristics. Finally, I discuss the large role of local biotic and abiotic variables driving the community assembly in unicellular taxa and eventually dictating how multiple ecosystem processes are performed. Present review highlights the fact that most microorganisms may not differ fundamentally from larger taxa in their large-scale distribution patterns. Yet, review also shows that many aspects of microbial macroecology are still relatively poorly understood and specific patterns depend on focal taxa and ecosystem concerned. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

Equinoctial asymmetry in the zonal distribution of scintillation as observed by GPS receivers in Indonesia

NASA Astrophysics Data System (ADS)

Abadi, P.; Otsuka, Y.; Shiokawa, K.; Husin, A.; Liu, Huixin; Saito, S.

2017-08-01

We investigate the azimuthal distribution of amplitude scintillation observed by Global Positioning System (GPS) ground receivers at Pontianak (0.0°S, 109.3°E; magnetic latitude: 9.8°S) and Bandung (6.9°S, 107.6°E; magnetic latitude: 16.7°S) in Indonesia in March and September from 2011 to 2015. The scintillation is found to occur more to the west than to the east in March at both stations, whereas no such zonal difference is found in September. We also analyze the zonal scintillation drift as estimated using three closely spaced single-frequency GPS receivers at Kototabang (0.2°S, 100.3°E; magnetic latitude: 9.9°S) in Indonesia during 2003-2015 and the zonal thermospheric neutral wind as measured by the CHAMP satellite at longitudes of 90°-120°E during 2001-2008. We find that the velocities of both the zonal scintillation drift and the neutral wind decrease with increasing latitudes. Interestingly, the latitudinal gradients of both the zonal scintillation drift and the neutral wind are steeper in March than in September. These steeper March gradients may be responsible for the increased westward altitudinal and latitudinal tilting of plasma bubbles in March. This equinoctial asymmetry could be responsible for the observed westward bias in scintillation in March, because the scintillation is more likely to occur when radio waves pass through longer lengths of plasma irregularities in the plasma bubbles.

Plants, birds and butterflies: short-term responses of species communities to climate warming vary by taxon and with altitude.

PubMed

Roth, Tobias; Plattner, Matthias; Amrhein, Valentin

2014-01-01

As a consequence of climate warming, species usually shift their distribution towards higher latitudes or altitudes. Yet, it is unclear how different taxonomic groups may respond to climate warming over larger altitudinal ranges. Here, we used data from the national biodiversity monitoring program of Switzerland, collected over an altitudinal range of 2500 m. Within the short period of eight years (2003-2010), we found significant shifts in communities of vascular plants, butterflies and birds. At low altitudes, communities of all species groups changed towards warm-dwelling species, corresponding to an average uphill shift of 8 m, 38 m and 42 m in plant, butterfly and bird communities, respectively. However, rates of community changes decreased with altitude in plants and butterflies, while bird communities changed towards warm-dwelling species at all altitudes. We found no decrease in community variation with respect to temperature niches of species, suggesting that climate warming has not led to more homogenous communities. The different community changes depending on altitude could not be explained by different changes of air temperatures, since during the 16 years between 1995 and 2010, summer temperatures in Switzerland rose by about 0.07°C per year at all altitudes. We discuss that land-use changes or increased disturbances may have prevented alpine plant and butterfly communities from changing towards warm-dwelling species. However, the findings are also consistent with the hypothesis that unlike birds, many alpine plant species in a warming climate could find suitable habitats within just a few metres, due to the highly varied surface of alpine landscapes. Our results may thus support the idea that for plants and butterflies and on a short temporal scale, alpine landscapes are safer places than lowlands in a warming world.

Plants, Birds and Butterflies: Short-Term Responses of Species Communities to Climate Warming Vary by Taxon and with Altitude

PubMed Central

Roth, Tobias; Plattner, Matthias; Amrhein, Valentin

2014-01-01

As a consequence of climate warming, species usually shift their distribution towards higher latitudes or altitudes. Yet, it is unclear how different taxonomic groups may respond to climate warming over larger altitudinal ranges. Here, we used data from the national biodiversity monitoring program of Switzerland, collected over an altitudinal range of 2500 m. Within the short period of eight years (2003–2010), we found significant shifts in communities of vascular plants, butterflies and birds. At low altitudes, communities of all species groups changed towards warm-dwelling species, corresponding to an average uphill shift of 8 m, 38 m and 42 m in plant, butterfly and bird communities, respectively. However, rates of community changes decreased with altitude in plants and butterflies, while bird communities changed towards warm-dwelling species at all altitudes. We found no decrease in community variation with respect to temperature niches of species, suggesting that climate warming has not led to more homogenous communities. The different community changes depending on altitude could not be explained by different changes of air temperatures, since during the 16 years between 1995 and 2010, summer temperatures in Switzerland rose by about 0.07°C per year at all altitudes. We discuss that land-use changes or increased disturbances may have prevented alpine plant and butterfly communities from changing towards warm-dwelling species. However, the findings are also consistent with the hypothesis that unlike birds, many alpine plant species in a warming climate could find suitable habitats within just a few metres, due to the highly varied surface of alpine landscapes. Our results may thus support the idea that for plants and butterflies and on a short temporal scale, alpine landscapes are safer places than lowlands in a warming world. PMID:24416144

Mountaintops phylogeography: A case study using small mammals from the Andes and the coast of central Chile

PubMed Central

González, Juan F.; Boric-Bargetto, Dusan; Torres-Pérez, Fernando

2017-01-01

We evaluated if two sigmodontine rodent taxa (Abrothrix olivacea and Phyllotis darwini) from the Andes and Coastal mountaintops of central Chile, experienced distributional shifts due to altitudinal movements of habitat and climate change during and after the Last Glacial Maximum (LGM). We tested the hypothesis that during LGM populations of both species experienced altitudinal shifts from the Andes to the lowlands and the coastal Cordillera, and then range retractions during interglacial towards higher elevations in the Andes. These distributional shifts may have left remnants populations on the mountaintops. We evaluated the occurrence of intraspecific lineages for each species, to construct distribution models at LGM and at present, as extreme climatic conditions for each lineage. Differences in distribution between extreme climatic conditions were interpreted as post-glacial distributional shifts. Abrothrix olivacea displayed a lineage with shared sequences between both mountain systems, whereas a second lineage was restricted to the Andes. A similar scenario of panmictic unit in the past was recovered for A. olivacea in the Andes, along with an additional unit that included localities from the rest of its distribution. For P. darwini, both lineages recovered were distributed in coastal and Andean mountain ranges at present as well, and structuring analyses for this species recovered coastal and Andean localities as panmictic units in the past. Niche modeling depicted differential postglacial expansions in the recovered lineages. Results suggest that historical events such as LGM triggered the descending of populations to Andean refuge areas (one of the A. olivacea’s lineages), to the lowlands, and to the coastal Cordillera. Backward movements of populations after glacial retreats may have left isolates on mountaintops of the coastal Cordillera, suggesting that current species distribution would be the outcome of climate change and habitat reconfiguration after LGM. PMID:28672032

Widespread tree mortality with the ongoing California drought: the roll of water balance and temperature

NASA Astrophysics Data System (ADS)

Goulden, M.; Bales, R. C.

2016-12-01

The southern Sierra Nevada experienced extreme drought, heat and forest dieback from 2012-16, with 50% below average P, 3oC above average T, and tens of millions of trees dying. The drought and dieback were widespread at the Southern Sierra Critical Zone Observatory (SSCZO). The SSCZO provides a rich suite of meteorological, ecological and hydrologic datasets, including many that began around 2010 and include two wet years followed by the intensifying drought. The SSCZO observations span an altitude gradient; this gradient includes a xeric pine and oak forest at 1200 m, which is near the lower ecotone of closed canopy forest, and a mesic pine and fir forest at 2100 m. Findings include: 1) Tree death was greater at 1200-m, following the altitudinal pattern seen across central CA, with dieback focused in the lower parts of species and ecosystem type ranges. 2) Mortality was associated with a year over year depletion of subsurface moisture. The cumulative overdraft (P-ET) at 1200 m exceeded 100 cm; the cumulative P-ET at 2100 m was near zero. 3) Much of the accelerated moisture depletion at 1200-m was associated with warmer temperatures and a greater evaporative demand. The 1200 and 2100 m sites experienced similar annual precipitation, and the rate of ET at comparable temperatures was also similar. The lower site was 5oC warmer on average, which led to 40% greater ET, and a more rapid depletion of belowground moisture. 4) A similar pattern was observed in Landsat and MODIS imagery. Mortality was high below 1600 m and low above 2000m. Mortality decreased rapidly with elevation and cooler temperatures from 1600 to 2000 m. Mortality in the 1600 to 2000 m zone was well correlated with Land Surface Temperature, with greater mortality on warm, southern slopes and less mortality on cool, northern slopes. In combination these findings illustrate the interacting effect of drought and temperature in controlling the patterns of tree death accross the Southern Sierra Nevada.

Unifying latitudinal gradients in range size and richness across marine and terrestrial systems

PubMed Central

Tomašových, Adam; Kennedy, Jonathan D.; Betzner, Tristan J.; Kuehnle, Nicole Bitler; Edie, Stewart; Kim, Sora; Supriya, K.; White, Alexander E.; Rahbek, Carsten; Huang, Shan; Price, Trevor D.; Jablonski, David

2016-01-01

Many marine and terrestrial clades show similar latitudinal gradients in species richness, but opposite gradients in range size—on land, ranges are the smallest in the tropics, whereas in the sea, ranges are the largest in the tropics. Therefore, richness gradients in marine and terrestrial systems do not arise from a shared latitudinal arrangement of species range sizes. Comparing terrestrial birds and marine bivalves, we find that gradients in range size are concordant at the level of genera. Here, both groups show a nested pattern in which narrow-ranging genera are confined to the tropics and broad-ranging genera extend across much of the gradient. We find that (i) genus range size and its variation with latitude is closely associated with per-genus species richness and (ii) broad-ranging genera contain more species both within and outside of the tropics when compared with tropical- or temperate-only genera. Within-genus species diversification thus promotes genus expansion to novel latitudes. Despite underlying differences in the species range-size gradients, species-rich genera are more likely to produce a descendant that extends its range relative to the ancestor's range. These results unify species richness gradients with those of genera, implying that birds and bivalves share similar latitudinal dynamics in net species diversification. PMID:27147094

The Shiny Cowbird, Molothrus bonariensis (Gmelin, 1789) (Aves: Icteridae), at 2,800 m asl in Quito, Ecuador.

PubMed

Crespo-Pérez, Verónica; Pinto, C Miguel; Carrión, Juan Manuel; Jarrín-E, Rubén D; Poveda, Cristian; de Vries, Tjitte

2016-01-01

The Shiny Cowbird, Molothrus bonariensis Gmelin, 1789, is a brood parasite of hundreds of small-bodied birds that is native to South American lowlands. Within the last 100 years this species has been expanding its range throughout the Caribbean, towards North America, but has rarely been seen above 2,000 m asl. Here, we present records of Shiny Cowbirds in Quito, a city located 2,800 m above sea level that harbors a bird community typical of the Andean valleys. We found two juvenile individuals parasitizing two different pairs of Rufous-collared Sparrow (Zonotrichia capensis Müller, 1776). This report constitutes an altitudinal range expansion of reproductive populations of ca. 500m, which may have beenprompted by anthropogenic disturbance.

The Shiny Cowbird, Molothrus bonariensis (Gmelin, 1789) (Aves: Icteridae), at 2,800 m asl in Quito, Ecuador

PubMed Central

Pinto, C. Miguel; Carrión, Juan Manuel; Jarrín-E, Rubén D.; Poveda, Cristian; de Vries, Tjitte

2016-01-01

Abstract Background The Shiny Cowbird, Molothrus bonariensis Gmelin, 1789, is a brood parasite of hundreds of small-bodied birds that is native to South American lowlands. Within the last 100 years this species has been expanding its range throughout the Caribbean, towards North America, but has rarely been seen above 2,000 m asl. New information Here, we present records of Shiny Cowbirds in Quito, a city located 2,800 m above sea level that harbors a bird community typical of the Andean valleys. We found two juvenile individuals parasitizing two different pairs of Rufous-collared Sparrow (Zonotrichia capensis Müller, 1776). This report constitutes an altitudinal range expansion of reproductive populations of ca. 500m, which may have beenprompted by anthropogenic disturbance. PMID:27226760

Nitrogen dynamics in the coastal Atlantic Forest of Southeast Brazil

NASA Astrophysics Data System (ADS)

Coletta, L. D.; Lins, S. M.; Ravagnani, E.; Gragnani, J. G.; Antonio, J.; Mazzi, E. A.; Martinelli, L. A.

2012-12-01

Tropical forests are important biomes by several things, among them, they are important reservoirs of carbon (C), nitrogen (N) and water (Bonan, 2008). In Brazil, at Sao Paulo State, the coastal Atlantic Forest runs along an altitudinal gradient from near seal level (Lowland Forest) up to more than 1,000m (Montane Forest). Soil carbon and nitrogen stocks as well as above ground biomass are higher at the Montante Forest in relation to the Lowland Forest. In contrast, annual fluxes of N2O and riverine N output are higher lower altitudes, although. Therefore, it seems that lower temperature at higher altitude limits N transfer between different reservoirs, which in turn leads to higher N stocks. In this study we test if the litter decomposition of Fabaceae and non Fabaceae leaves at higher altitudes also decomposes slower than at low altitudes. At the same time we also test if Fabaceae leaves decompose faster than non Fabaceae leaves due to the higher N content and lower C:N ratio of the former in comparison to the later. Preliminary results indicate that both hypothesis seems to be right.

Amphibians of Serra Bonita, southern Bahia: a new hotpoint within Brazil's Atlantic Forest hotspot.

PubMed

Dias, Iuri Ribeiro; Medeiros, Tadeu Teixeira; Vila Nova, Marcos Ferreira; Solé, Mirco

2014-01-01

We studied the amphibian community of the Private Reserve of Natural Heritage (RPPN) Serra Bonita, an area of 20 km(2) with steep altitudinal gradients (200-950 m a.s.l.) located in the municipalities of Camacan and Pau-Brasil, southern Bahia State, Brazil. Data were obtained at 38 sampling sites (including ponds and transects within the forest and in streams), through active and visual and acoustic searches, pitfall traps, and opportunistic encounters. We recorded 80 amphibian species distributed in 15 families: Aromobatidae (1), Brachycephalidae (3), Bufonidae (4), Centrolenidae (2), Ceratophryidae (1), Craugastoridae (7), Eleutherodactylidae (2), Hemiphractidae (2), Hylidae (42), Hylodidae (1), Leptodactylidae (7), Microhylidae (3), Siphonopidae (1), Odontophrynidae (3) and Pipidae (1). Species richness was positively correlated with monthly rainfall. Near 36% of the species were found in strictly forest environments, 15% are endemic to Bahia State and 77.2% are endemic to the Atlantic Forest biome. The large species diversity of this small area, the high degree of endemism and the taxonomic and biogeographic significance turn the Serra Bonita mountain into a hotpoint for amphibians within Brazil's Atlantic Forest hotspot.

[Geographic variation of seed morphological traits of Picea schrenkiana var. tianschanica in Tianshan Mountains, Xinjiang of Northwest China].

PubMed

Liu, Gui-Feng; Zang, Run-Guo; Liu, Hua; Bai, Zhi-Qiang; Guo, Zhong-Jun; Ding, Yi

2012-06-01

Taking the Picea schrenkiana var. tianschanica forests at three sites with different longitudes (Zhaosu, Tianchi, and Qitai) in Tianshan Mountains as the objects, the cones were collected along an altitudinal gradient to analyze the variation of their seed morphological traits (seed scale length and width, seed scale length/width ratio, seed wing length and width, seed wing length/ width ratio, seed length and width, and seed length/width ratio). All the seed traits except seed width tended to decrease with increasing altitude. The seed traits except seed wing width, seed width, and seed length/width ratio all had significant negative correlations with altitude. Seed scale length and width and seed scale length/width ratio had significant positive correlations with longitude. Seed scale length, seed scale length/width ratio, and seed wing length/width ratio had significant negative correlations with slope degree. No significant correlations were observed between the seed traits except seed wing width and the slope aspect. Altitude was the main factor affecting the seed scale length, seed scale length/width ratio, and seed wing length/width ratio.

Changes in plant biomass and species composition of alpine Kobresia meadows along altitudinal gradient on the Qinghai-Tibetan Plateau.

PubMed

Wang, ChangTing; Cao, GuangMin; Wang, QiLan; Jing, ZengChun; Ding, LuMing; Long, RuiJun

2008-01-01

Alpine Kobresia meadows are major vegetation types on the Qinghai-Tibetan Plateau. There is growing concern over their relationships among biodiversity, productivity and environments. Despite the importance of species composition, species richness, the type of different growth forms, and plant biomass structure for Kobresia meadow ecosystems, few studies have been focused on the relationship between biomass and environmental gradient in the Kobresia meadow plant communities, particularly in relation to soil moisture and edaphic gradients. We measured the plant species composition, herbaceous litter, aboveground and belowground biomass in three Kobresia meadow plant communities in Haibei Alpine Meadow Ecosystem Research Station from 2001 to 2004. Community differences in plant species composition were reflected in biomass distribution. The total biomass showed a decrease from 13196.96+/-719.69 g/m(2) in the sedge-dominated K. tibetica swamp to 2869.58+/-147.52 g/m(2) in the forb and sedge dominated K. pygmaea meadow, and to 2153.08+/-141.95 g/m(2) in the forbs and grasses dominated K. humilis along with the increase of altitude. The vertical distribution of belowground biomass is distinct in the three meadow communities, and the belowground biomass at the depth of 0-10 cm in K. tibetica swamp meadow was significantly higher than that in K. humilis and K. pygmaea meadows (P<0.01). The herbaceous litter in K. tibetica swamp was significantly higher than those in K. pygnaeca and K. humilis meadows. The effects of plant litter are enhanced when ground water and soil moisture levels are raised. The relative importance of litter and vegetation may vary with soil water availability. In the K. tibetica swamp, total biomass was negatively correlated to species richness (P<0.05); aboveground biomass was positively correlated to soil organic matter, soil moisture, and plant cover (P<0.05); belowground biomass was positively correlated with soil moisture (P<0.05). However, in the K. pygnaeca and K. humilis meadow communities, aboveground biomass was positively correlated to soil organic matter and soil total nitrogen (P<0.05). This suggests that the distribution of biomass coincided with soil moisture and edaphic gradient in alpine meadows.

Toward the Application of the Maximum Entropy Production Principle to a Broader Range of Far From Equilibrium Dissipative Systems

NASA Astrophysics Data System (ADS)

Lineweaver, C. H.

2005-12-01

The principle of Maximum Entropy Production (MEP) is being usefully applied to a wide range of non-equilibrium processes including flows in planetary atmospheres and the bioenergetics of photosynthesis. Our goal of applying the principle of maximum entropy production to an even wider range of Far From Equilibrium Dissipative Systems (FFEDS) depends on the reproducibility of the evolution of the system from macro-state A to macro-state B. In an attempt to apply the principle of MEP to astronomical and cosmological structures, we investigate the problematic relationship between gravity and entropy. In the context of open and non-equilibrium systems, we use a generalization of the Gibbs free energy to include the sources of free energy extracted by non-living FFEDS such as hurricanes and convection cells. Redox potential gradients and thermal and pressure gradients provide the free energy for a broad range of FFEDS, both living and non-living. However, these gradients have to be within certain ranges. If the gradients are too weak, FFEDS do not appear. If the gradients are too strong FFEDS disappear. Living and non-living FFEDS often have different source gradients (redox potential gradients vs thermal and pressure gradients) and when they share the same gradient, they exploit different ranges of the gradient. In a preliminary attempt to distinguish living from non-living FFEDS, we investigate the parameter space of: type of gradient and steepness of gradient.

Altitudinal variation of phenolic contents in flowering heads of Arnica montana cv. ARBO: a 3-year comparison.

PubMed

Spitaler, Renate; Winkler, Andrea; Lins, Isabella; Yanar, Sema; Stuppner, Hermann; Zidorn, Christian

2008-03-01

In continuation of our studies of altitudinal effects on secondary metabolite profile of flowering heads from taxa of the Asteraceae, we investigated phenolic contents and radical scavenging potential from cultivated plants of Arnica montana cv. ARBO during the growing seasons 2003, 2004, and 2005. By conducting experiments on potted plants, we excluded that differences in phenolic contents from plants grown at different altitudes were related primarily to differences in soil composition at these sites. To assess altitudinal and interseasonal variation, plants of A. montana cultivar ARBO were grown in nine experimental plots at altitudes between 590 and 2,230 m at Mount Patscherkofel near Innsbruck, Austria. In all growing seasons and regardless of the soil the plants were grown in, the proportion of flavonoids with vicinal-free hydroxy groups in ring B to flavonoids lacking this feature, and the total amount of caffeic acid derivatives, significantly increased with elevation. These increases of antioxidant phenolics corresponded to an increase of the radical scavenging potential of extracts from plants grown at different altitudes. The results are discussed in regard to previous studies that suggest that enhanced UV-B radiation and decreased temperatures trigger augmented biosynthesis of UV-absorbing and antioxidant phenolics in higher plants.

HPTLC detection of altitudinal variation of the potential antivenin stigmasterol in different populations of the tropical ethnic antidote Rauvolfia serpentina.

PubMed

Dey, Abhijit; Pandey, Devendra Kumar

2014-09-01

To determine the altitudinal variation of stigmasterol, a potential antivenin, in roots from seven populations of Rauvolfia serpentina (L). Benth. ex Kurz. (Apocynaceae) (R. serpentina), an important herb found in Indian subcontinent which has long been used in the treatment of snakebite, blood pressure and schizophrenia. Altitudinal variation of stigmasterol content in R. serpentina roots was analyzed by high performance thin layer chromatography. Chromatography was performed on silica gel 60 F254 thin layer chromatography plates with benzene-acetone 86:14 (v/v) as mobile phase. Densitometric analysis was done at λ=366 nm after derivatization with vanillin-10% (v/v) sulphuric acid alcohol reagent. The method was validated for precision and recovery. The present experiment demonstrates a simple, rapid, precise and sensitive high performance thin layer chromatography protocol for qualitative and quantitative determination of stigmasterol from different populations of R. serpentina. Results demonstrated that in root samples stigmasterol was present at Rf value of 0.44. This investigation demonstrates that stigmasterol content in R. serpentina roots varies in different altitudes. Popular ethnomedicinal use of this herb against snakebite may be contributed by the occurrence of stigmasterol in its roots. Copyright © 2014 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

Seasonal and altitudinal changes in population density of 20 species of Drosophila in Chamundi hill.

PubMed

Guruprasad, Basavarajpur R; Hegde, Shridhar N; Krishna, Mysore S

2010-01-01

A year long study was conducted to analyze the altitudinal and seasonal variation in a population of Drosophila (Diptera: Drosophilidae) on Chamundi hill of Mysore, Karnataka State, India. A total of 16,671 Drosophila flies belonging to 20 species of 4 subgenera were collected at altitudes of 680 m, 780 m, 880 m and 980 m. The subgenus Sophophora was predominant with 14 species and the subgenus Drosilopha was least represented with only a single species. Cluster analysis and constancy methods were used to analyze the species occurrence qualitatively. Altitudinal changes in the population density, and relative abundance of the different species at different seasons were also studied. The diversity of the Drosophila community was assessed by applying the Simpson and Berger-Parker indices. At 680 m the Simpson Index was low at 0.129 and the Berger- Parker index was high at 1.1 at 980 m. Linear regression showed that the Drosophila community was positively correlated with rainfall but not elevation, Furthermore the density of Drosophila changed significantly in different seasons (F = 11.20, df 2, 9; P<0.004). The distributional pattern of a species or related group of species was uneven in space and time. D. malerkotliana and D. nasuta were found at all altitudes and can be considered as dominant species.

Altitudinal and climatic associations of seed dormancy and flowering traits evidence adaptation of annual life cycle timing in Arabidopsis thaliana.

PubMed

Vidigal, Deborah S; Marques, Alexandre C S S; Willems, Leo A J; Buijs, Gonda; Méndez-Vigo, Belén; Hilhorst, Henk W M; Bentsink, Leónie; Picó, F Xavier; Alonso-Blanco, Carlos

2016-08-01

The temporal control or timing of the life cycle of annual plants is presumed to provide adaptive strategies to escape harsh environments for survival and reproduction. This is mainly determined by the timing of germination, which is controlled by the level of seed dormancy, and of flowering initiation. However, the environmental factors driving the evolution of plant life cycles remain largely unknown. To address this question we have analysed nine quantitative life history traits, in a native regional collection of 300 wild accessions of Arabidopsis thaliana. Seed dormancy and flowering time were negatively correlated, indicating that these traits have coevolved. In addition, environmental-phenotypic analyses detected strong altitudinal and climatic clines for most life history traits. Overall, accessions showing life cycles with early flowering, small seeds, high seed dormancy and slow germination rate were associated with locations exposed to high temperature, low summer precipitation and high radiation. Furthermore, we analysed the expression level of the positive regulator of seed dormancy DELAY OF GERMINATION 1 (DOG1), finding similar but weaker altitudinal and climatic patterns than seed dormancy. Therefore, DOG1 regulatory mutations are likely to provide a quantitative molecular mechanism for the adaptation of A. thaliana life cycle to altitude and climate. © 2016 John Wiley & Sons Ltd.

Are there evidences of altitudinal effects of air temperature trends in the European Alps 1820-2013?

NASA Astrophysics Data System (ADS)

Schoener, W.; Auer, I.; Chimani, B.; Garnekind, M.; Haslinger, K.

2013-12-01

We use the HISTALP data set (www.zamg.ac.at/histalp) in order to assess the elevation dependency of air temperature trends within the European Alps. The evidence of altitudinal effects of the climate warming (with higher sensitivity of high mountain regions to warming) is a key statement, or at least key hypothesis, in many studies. The high relevance of such statement resp. hypothesis is obvious if one consider the impacts resulting from such fact, such as snow- and glacier melting and related effects for mountain hydrology. The HISTALP data set stands out with respect to its series lengths and its high level of homogenisation. Interestingly, the HISTALP temperature data show no clear altitudinal dependency of warming or cooling trends within the period 1820-2013. Additionally, a rather homogenous temporal trend could be observed within the entire Greater Alpine Region (GAR). Because HISTALP include also air pressure and vapour pressure series, we could compare our measured air temperatures with mean-column air temperatures, computed by the barometric formula, which were derived from the independently measured air pressure data (using vapour pressure to account for the atmospheric water content) at low resp. high elevations. Computed mean column temperatures are in good agreement with observed temperatures, indicating generally homogenous temporal temperature trend behaviour at different elevations. Our finding contradicts several results from climate modelling attempts and also other studies investigating Alpine temperature trends. We conclude that, whereas modelling results are still limited in the assessment of altitudinal effect of temperature trends from missing atmospheric processes captured by the models, the difference of the trend behaviour compared to other analyses of instrumental air temperatures comes from the seasonal base taken as the basis for trend estimation. It appears that opposite trend in spring and autumn for the period 1980-2000, respectively, levels each other out for the annual temperature trend.

Spatial-altitudinal and temporal variation of Degree Day Factors (DDFs) in the Upper Indus Basin

NASA Astrophysics Data System (ADS)

Khan, Asif; Attaullah, Haleema; Masud, Tabinda; Khan, Mujahid

2017-04-01

Melt contribution from snow and ice in the Hindukush-Karakoram-Himalayan (HKH) region could account for more than 80% of annual river flows in the Upper Indus Basin (UIB). Increase or decrease in precipitation, energy input and glacier reserves can significantly affect water resources of this region. Therefore improved hydrological modelling and accurate future water resources prediction are vital for food production and hydro-power generation for millions of people living downstream, and are intensively needed. In mountain regions Degree Day Factors (DDFs) significantly vary on spatial and altitudinal basis, and are primary inputs of temperature-based hydrological modelling. However previous studies have used different DDFs as calibration parameters without due attention to the physical meaning of the values employed, and these estimates possess significant variability and uncertainty. This study provides estimates of DDFs for various altitudinal zones in the UIB at sub-basin level. Snow, clean ice and ice with debris cover bear different melt rates (or DDFs), therefore areally-averaged DDFs based on snow, clean and debris-covered ice classes in various altitudinal zones have been estimated for all sub-basins of the UIB. Zonal estimates of DDFs in the current study are significantly different from earlier adopted DDFs, hence suggest a revisit of previous hydrological modelling studies. DDFs presented in current study have been validated by using Snowmelt Runoff Model (SRM) in various sub-basins with good Nash Sutcliffe coefficients (R2 > 0.85) and low volumetric errors (Dv<10%). DDFs and methods provided in the current study can be used in future improved hydrological modelling and to provide accurate predictions of future river flows changes. The methodology used for estimation of DDFs is robust, and can be adopted to produce such estimates in other regions of the, particularly in the nearby other HKH basins.

Century long assessment of herbaceous plants' physiological responses to climate change in Switzerland

NASA Astrophysics Data System (ADS)

Moreno-Gutierrez, Cristina; Kahmen, Ansgar

2017-04-01

The isotopic analysis of archived plant material offers the exceptional opportunity to reconstruct the physiological activity of plants over long time periods and thus, to assess plant responses to environmental changes during the last centuries. In addition, the stable isotope analysis of herbarium samples offers the opportunity to reconstruct the physiological processes of a large range of different plant species and from different environments. Interestingly, only few studies have to date assessed these archives. We will present a novel analysis of leaf nitrogen, oxygen and carbon isotope ratios of more than a thousand herbarium specimens collected since 1800 until present from the unique herbaria hold at the University of Basel. The objective of our study was to assess century-long physiological responses of herbaceous plant species from different plant functional groups and along an altitudinal gradient in Switzerland. The goal of our study was to determine with our investigations the long-term responses of plants to climate change. Such investigations are important as they allow to assess long-term processes of acclimation and adaptation in plants to global enviromental change. In our study we found that herbaceous plants have increased their intrinsic water use efficiency in response to increasing atmospheric CO2 concentration but this increment was higher in plants from higher altitudes, due to the higher efficiency of CO2 assimilation of alpine plants compared to plants from lowlands. There were also differences among functional groups, with grasses and forbs showing the highest increments. In addition, herbaceous plants showed a decreasing trend with time in their N isotopic composition, which may indicate progressive N limitation due to higher biological activity with increasing atmospheric CO2 concentration.

Mobile carbohydrates in Himalayan treeline trees I. Evidence for carbon gain limitation but not for growth limitation.

PubMed

Li, Mai-He; Xiao, Wen-Fa; Wang, San-Gen; Cheng, Gen-Wei; Cherubini, Paolo; Cai, Xaio-Hu; Liu, Xing-Liang; Wang, Xiao-Dan; Zhu, Wan-Ze

2008-08-01

To test whether the altitudinal distribution of trees is determined by a carbon shortage or an insufficient sugar fraction (sugar:starch ratio) in treeline trees, we studied the status of nonstructural carbohydrates (NSC) and their components (total soluble sugars and starch) in Abies fabri (Mast.) Craib and Picea balfouriana var. hirtella Rehd. et Wils. trees along three elevational gradients, ranging from lower elevations to the alpine treeline, on the eastern edge of the Tibetan Plateau. For comparison, we investigated a low-altitude species (Tsuga yunnanensis (Franch.) Pritz.) which served as a warm-climate reference because it is distributed in closed montane forests below 3100 m a.s.l. in the study area. The carbon status of T. yunnanensis responded to altitude differently from that of the treeline species. At the species level, total NSC was not consistently more abundant in treeline trees than in trees of the same species growing at lower elevations. Thus there was no consistent evidence for carbon limitation of growth in treeline trees. For the three treeline species studied (P. balfouriana and A. fabri in the Kang-Ding Valley and A. fabri in the Mo-Xi Valley), winter NSC concentrations in treeline trees were significantly lower than in lower-elevation trees of the same species, suggesting that, in winter, carbon is limited in treeline trees. However, in no case was there total overwinter depletion of NSC or its components in treeline trees. Treeline and low-altitude species had similar sugar:starch ratios of about three at their upper-elevational limits in April. We conclude that survival and growth of trees at the elevational or latitudinal climate limit depend not only on NSC concentration in perennial tissues, but also on the maintenance of an overwintering sugar:starch ratio greater than three.

Mesophyll conductance and leaf carbon isotope composition of two high elevation conifers along an altitudinal gradient

NASA Astrophysics Data System (ADS)

Guo, J.; Beverly, D.; Cook, C.; Ewers, B.; Williams, D. G.

2016-12-01

Carbon isotope ratio values (δ13C) of conifer leaf material generally increases with elevation, potentially reflecting decreases in the leaf internal to ambient CO2 concentration ratio (Ci/Ca) during photosynthesis. Reduced stomatal conductance or increased carboxylation capacity with increasing elevation could account for these patterns. But some studies reported conifers δ13C increased with altitude consistently, but Ci/Ca did not significantly decrease and leaf nitrogen content remained constant with increasing of altitude in Central Rockies. Variation in leaf mesophyll conductance to CO2 diffusion, which influences leaf δ13C independently of effects related to stomatal conductance and carboxylation demand, might reconcile these conflicting observations. Leaf mass per unit area (LMA) increases with altitude and often correlates with δ13C and mesophyll conductance. Therefore, we hypothesized that increases in δ13C of conifers with altitude are controlled mainly by changes in mesophyll conductance. To test this hypothesis, leaf δ13C, photosynthetic capacity, leaf nitrogen content, LMA, and mesophyll conductance were determined on leaves of two dominant conifers (Pinus contorta and Picea engelmannii) along a 90-km transect in SE Wyoming at altitudes ranging from 2400 to 3200 m above sea level. Mesophyll conductance was determined by on-line 13C discrimination using isotope laser spectroscopy. We expected to observe relatively small differences in stomatal conductance and decreases in mesophyll conductance from lower and higher altitude sites. Such a pattern would have important implications for how differences in leaf δ13C values across altitude are interpreted in relation to forest water use and productivity from scaling of leaf-level water-use efficiency.

[New findings on the geographic distribution of the verrucarum group (Diptera: Psychodidae) in Colombia].

PubMed

Bejarano, Eduar Elías; Sierra, Diana; Vélez, Iván Darío

2003-09-01

The incrimination of sand flies belonging to verrucarum species group in the leishmaniasis transmission underscores the need for a detailed information on the geographical distribution of these species. The current listing adds 34 new records that extend significantly the knowledge of the geographical distribution of the verrucarum group in Colombia. The most important new records pertain to Lutzomyia spinicrassa in the tropical dry forest of the Atlantic coast, Lutzomyia ovallesi in the Orinoco and Amazon River watersheds regions of Colombia, and the sympatric occurrence of Lutzomyia spinicrassa and Lutzomyia quasitownsendi in the eastern chain of the Andes mountains. Additionally, the municipal and altitudinal distributions are compiled for 19 new species recorded for Colombia. The series townsendi of the verrucarum group generally restricted to premontane and lower montane zones based on distribution data on Lutzomyia longiflocosa, L. quasitownsendi, Lutzomyia sauroida, L. spinicrassa, Lutzomyia torvida, Lutzomyia townsendi and Lutzomyia youngi. The series verrucarum is distributed from the tropical lowland to the montane zones, and includes species with wide geographical range (Lutzomyia evansi, Lutzomyia columbiana, L. ovallesi, Lutzomyia nuneztovari, Lutzomyia nevesi), and species of highly endemic distribution (Lutzomyia andina, Lutzomyia disiuncta, Lutzomyia moralesi, Lutzomyia antioquiensis). Members of the series pia (Lutzomyia pia, Lutzomyia limafalcaoae) and the series serrana (Lutzomyia serrana) occur from the tropical lowlands to the lower montane zones. The altitudinal divergences may be intrinsically tied to speciation process, especially as it relates to the climatic and geologic events that have affected the flora and fauna of the Andean region.

Leaf δ13C variability with elevation, slope aspect, and precipitation in the southwest United States

USGS Publications Warehouse

Van De Water, Peter K.; Leavitt, Steven W.; Betancourt, Julio L.

2002-01-01

Leaves from several desert and woodland species, including gymnosperms and angiosperms with both C3 and C4 physiology, were analyzed to detect trends in δ13Cleaf with elevation and slope aspect along two transects in southeastern Utah and south-central New Mexico, USA. The main difference between the two transects is the steeper elevational gradient for mean annual and summer precipitation in the southern transect. For any given species, we found that isotopic differences between individual plants growing at the same site commonly equal differences measured for plants along the entire altitudinal gradient. In C3 plants, δ13Cleaf values become slightly enriched at the lowest elevations, the opposite of trends identified in more humid regions. Apparently, increasing water-use efficiency with drought stress offsets the influence of other biotic and abiotic factors that operate to decrease isotopic discrimination with elevation. For some species shared by the two transects (e.g., Pinus edulis and Cercocarpus montanus), δ13Cleaf values are dramatically depleted at sites that receive more than 550 mm mean annual precipitation, roughly the boundary (pedalfer-pedocal) at which soils commonly fill to field capacity in summer and carbonates are leached. We hypothesize that, in summer-wet areas, this may represent the boundary at which drought stress overtakes other factors in determining the sign of δ13Cleaf with elevation. The opposition of isotopic trends with elevation in arid versus humid regions cautions against standard correction for elevation in comparative studies of δ13Cleaf.

Preliminary inventory and classification of indigenous afromontane forests on the Blyde River Canyon Nature Reserve, Mpumalanga, South Africa

PubMed Central

Lötter, Mervyn C; Beck, Hans T

2004-01-01

Background Mixed evergreen forests form the smallest, most widely distributed and fragmented biome in southern Africa. Within South Africa, 44% of this vegetation type has been transformed. Afromontane forest only covers 0.56 % of South Africa, yet it contains 5.35% of South Africa's plant species. Prior to this investigation of the indigenous forests on the Blyde River Canyon Nature Reserve (BRCNR), very little was known about the size, floristic composition and conservation status of the forest biome conserved within the reserve. We report here an inventory of the forest size, fragmentation, species composition and the basic floristic communities along environmental gradients. Results A total of 2111 ha of forest occurs on Blyde River Canyon Nature Reserve. The forest is fragmented, with a total of 60 forest patches recorded, varying from 0.21 ha to 567 ha in size. On average, patch size was 23 ha. Two forest communities – high altitude moist afromontane forest and low altitude dry afromontane forest – are identified. Sub-communities are recognized based on canopy development and slope, respectively. An altitudinal gradient accounts for most of the variation within the forest communities. Conclusion BRCNR has a fragmented network of small forest patches that together make up 7.3% of the reserve's surface area. These forest patches host a variety of forest-dependent trees, including some species considered rare, insufficiently known, or listed under the Red Data List of South African Plants. The fragmented nature of the relatively small forest patches accentuates the need for careful fire management and stringent alien plant control. PMID:15287991

Range-Wide Latitudinal and Elevational Temperature Gradients for the World's Terrestrial Birds: Implications under Global Climate Change

PubMed Central

La Sorte, Frank A.; Butchart, Stuart H. M.; Jetz, Walter; Böhning-Gaese, Katrin

2014-01-01

Species' geographical distributions are tracking latitudinal and elevational surface temperature gradients under global climate change. To evaluate the opportunities to track these gradients across space, we provide a first baseline assessment of the steepness of these gradients for the world's terrestrial birds. Within the breeding ranges of 9,014 bird species, we characterized the spatial gradients in temperature along latitude and elevation for all and a subset of bird species, respectively. We summarized these temperature gradients globally for threatened and non-threatened species and determined how their steepness varied based on species' geography (range size, shape, and orientation) and projected changes in temperature under climate change. Elevational temperature gradients were steepest for species in Africa, western North and South America, and central Asia and shallowest in Australasia, insular IndoMalaya, and the Neotropical lowlands. Latitudinal temperature gradients were steepest for extratropical species, especially in the Northern Hemisphere. Threatened species had shallower elevational gradients whereas latitudinal gradients differed little between threatened and non-threatened species. The strength of elevational gradients was positively correlated with projected changes in temperature. For latitudinal gradients, this relationship only held for extratropical species. The strength of latitudinal gradients was better predicted by species' geography, but primarily for extratropical species. Our findings suggest threatened species are associated with shallower elevational temperature gradients, whereas steep latitudinal gradients are most prevalent outside the tropics where fewer bird species occur year-round. Future modeling and mitigation efforts would benefit from the development of finer grain distributional data to ascertain how these gradients are structured within species' ranges, how and why these gradients vary among species, and the capacity of species to utilize these gradients under climate change. PMID:24852009

Mountain evaporation profiles on the island of Hawai'i

NASA Astrophysics Data System (ADS)

Bean, Christine; Juvik, James O.; Nullet, Dennis

1994-04-01

Evaporation was measured along three altitudinal transects on Mauna Loa, on the island of Hawai'i. Stations lie between 70 and 3400 m a.s.l. and included environments ranging from tropical rainforest with 6 m year -1 annual rainfall to barren, subalpine lava fields in a dry environment above a persistent, subsidence temperature inversion. Average daily evaporation decreased with elevation between sea-level and about 1200 m, and then increased with elevation above that level. Evaporation minima ranged from 1.9 to 2.2 mm day -1. The maximum evaporation rate, 6.1 mm day -1, was at the highest site, Mauna Loa Observatory at 3400 m. Analysis of pan-evaporation data collected at 3400 m showed that standard formulae based on other meteorological variables provided good approximations of measured evaporation. Transect data were also compared with similar measurements from mountains on other Hawaiian islands.

Cell wall modifications of two Arabidopsis thaliana ecotypes, Col and Sha, in response to sub-optimal growth conditions: An integrative study.

PubMed

Duruflé, Harold; Hervé, Vincent; Ranocha, Philippe; Balliau, Thierry; Zivy, Michel; Chourré, Josiane; San Clemente, Hélène; Burlat, Vincent; Albenne, Cécile; Déjean, Sébastien; Jamet, Elisabeth; Dunand, Christophe

2017-10-01

With the global temperature change, plant adaptations are predicted, but little is known about the molecular mechanisms underlying them. Arabidopsis thaliana is a model plant adapted to various environmental conditions, in particular able to develop along an altitudinal gradient. Two ecotypes, Columbia (Col) growing at low altitude, and Shahdara (Sha) growing at 3400m, have been studied at optimal and sub-optimal growth temperature (22°C vs 15°C). Macro- and micro-phenotyping, cell wall monosaccharides analyses, cell wall proteomics, and transcriptomics have been performed in order to accomplish an integrative analysis. The analysis has been focused on cell walls (CWs) which are assumed to play roles in response to environmental changes. At 15°C, both ecotypes presented characteristic morphological traits of low temperature growth acclimation such as reduced rosette diameter, increased number of leaves, modifications of their CW composition and cuticle reinforcement. Altogether, the integrative analysis has allowed identifying several candidate genes/proteins possibly involved in the cell wall modifications observed during the temperature acclimation response. Copyright © 2017 Elsevier B.V. All rights reserved.

Amphibians of Serra Bonita, southern Bahia: a new hotpoint within Brazil’s Atlantic Forest hotspot

PubMed Central

Dias, Iuri Ribeiro; Medeiros, Tadeu Teixeira; Vila Nova, Marcos Ferreira; Solé, Mirco

2014-01-01

Abstract We studied the amphibian community of the Private Reserve of Natural Heritage (RPPN) Serra Bonita, an area of 20 km2 with steep altitudinal gradients (200–950 m a.s.l.) located in the municipalities of Camacan and Pau-Brasil, southern Bahia State, Brazil. Data were obtained at 38 sampling sites (including ponds and transects within the forest and in streams), through active and visual and acoustic searches, pitfall traps, and opportunistic encounters. We recorded 80 amphibian species distributed in 15 families: Aromobatidae (1), Brachycephalidae (3), Bufonidae (4), Centrolenidae (2), Ceratophryidae (1), Craugastoridae (7), Eleutherodactylidae (2), Hemiphractidae (2), Hylidae (42), Hylodidae (1), Leptodactylidae (7), Microhylidae (3), Siphonopidae (1), Odontophrynidae (3) and Pipidae (1). Species richness was positively correlated with monthly rainfall. Near 36% of the species were found in strictly forest environments, 15% are endemic to Bahia State and 77.2% are endemic to the Atlantic Forest biome. The large species diversity of this small area, the high degree of endemism and the taxonomic and biogeographic significance turn the Serra Bonita mountain into a hotpoint for amphibians within Brazil’s Atlantic Forest hotspot. PMID:25408616

Inferring late-Holocene climate in the Ecuadorian Andes using a chironomid-based temperature inference model

NASA Astrophysics Data System (ADS)

Matthews-Bird, Frazer; Brooks, Stephen J.; Holden, Philip B.; Montoya, Encarni; Gosling, William D.

2016-06-01

Presented here is the first chironomid calibration data set for tropical South America. Surface sediments were collected from 59 lakes across Bolivia (15 lakes), Peru (32 lakes), and Ecuador (12 lakes) between 2004 and 2013 over an altitudinal gradient from 150 m above sea level (a.s.l) to 4655 m a.s.l, between 0-17° S and 64-78° W. The study sites cover a mean annual temperature (MAT) gradient of 25 °C. In total, 55 chironomid taxa were identified in the 59 calibration data set lakes. When used as a single explanatory variable, MAT explains 12.9 % of the variance (λ1/λ2 = 1.431). Two inference models were developed using weighted averaging (WA) and Bayesian methods. The best-performing model using conventional statistical methods was a WA (inverse) model (R2jack = 0.890; RMSEPjack = 2.404 °C, RMSEP - root mean squared error of prediction; mean biasjack = -0.017 °C; max biasjack = 4.665 °C). The Bayesian method produced a model with R2jack = 0.909, RMSEPjack = 2.373 °C, mean biasjack = 0.598 °C, and max biasjack = 3.158 °C. Both models were used to infer past temperatures from a ca. 3000-year record from the tropical Andes of Ecuador, Laguna Pindo. Inferred temperatures fluctuated around modern-day conditions but showed significant departures at certain intervals (ca. 1600 cal yr BP; ca. 3000-2500 cal yr BP). Both methods (WA and Bayesian) showed similar patterns of temperature variability; however, the magnitude of fluctuations differed. In general the WA method was more variable and often underestimated Holocene temperatures (by ca. -7 ± 2.5 °C relative to the modern period). The Bayesian method provided temperature anomaly estimates for cool periods that lay within the expected range of the Holocene (ca. -3 ± 3.4 °C). The error associated with both reconstructions is consistent with a constant temperature of 20 °C for the past 3000 years. We would caution, however, against an over-interpretation at this stage. The reconstruction can only currently be deemed qualitative and requires more research before quantitative estimates can be generated with confidence. Increasing the number, and spread, of lakes in the calibration data set would enable the detection of smaller climate signals.

From bed topography to ice thickness: GlaRe, a GIS tool to reconstruct the surface of palaeoglaciers

NASA Astrophysics Data System (ADS)

Pellitero, Ramon; Rea, Brice; Spagnolo, Matteo; Bakke, Jostein; Ivy-Ochs, Susan; Frew, Craig; Hughes, Philip; Ribolini, Adriano; Renssen, Hans; Lukas, Sven

2016-04-01

We present GlaRe, A GIS tool that automatically reconstructs the 3D geometry for palaeoglaciers given the bed topography. This tool utilises a numerical approach and can work using a minimum of morphological evidence i.e. the position of the palaeoglacier front. The numerical approach is based on an iterative solution to the perfect plasticity assumption for ice rheology, explained in Benn and Hulton (2010). The tool can be run in ArcGIS 10.1 (ArcInfo license) and later updates and the toolset is written in Python code. The GlaRe toolbox presented in this paper implements a well-established approach for the determination of palaeoglacier equilibrium profiles. Significantly it permits users to quickly run multiple glacier reconstructions which were previously very laborious and time consuming (typically days for a single valley glacier). The implementation of GlaRe will facilitate the reconstruction of large numbers of palaeoglaciers which will provide opportunities for such research addressing at least two fundamental problems: 1. Investigation of the dynamics of palaeoglaciers. Glacier reconstructions are often based on a rigorous interpretation of glacial landforms but not always sufficient attention and/or time has been given to the actual reconstruction of the glacier surface, which is crucial for the calculation of palaeoglacier ELAs and subsequent derivation of quantitative palaeoclimatic data. 2. the ability to run large numbers of reconstructions and over much larger spatial areas provides an opportunity to undertake palaeoglaciers reconstructions across entire mountain, ranges, regions or even continents, allowing climatic gradients and atmospheric circulation patterns to be elucidated. The tool performance has been evaluated by comparing two extant glaciers, an icefield and a cirque/valley glacier from which the subglacial topography is known with a basic reconstruction using GlaRe. Results from the comparisons between extant glacier surfaces and modelled ones show very similar ELA values on the order of 10-20 meter error (which would account for a 0.065-0.13 K degree variation on a typical -6.5 K altitudinal gradient), and these can be improved further by increasing the number of flowlines and using F factors where needed. GlaRe is able to quickly generate robust palaeoglacier surfaces based on the very limited inputs often available from the geomorphological record.

Atmospheric salt deposition in a tropical mountain rainforest at the eastern Andean slopes of south Ecuador - Pacific or Atlantic origin?

NASA Astrophysics Data System (ADS)

Makowski Giannoni, Sandro; Trachte, Katja; Rollenbeck, Ruetger; Lehnert, Lukas; Fuchs, Julia; Bendix, Joerg

2016-08-01

Sea salt (NaCl) has recently been proven to be of the utmost importance for ecosystem functioning in Amazon lowland forests because of its impact on herbivory, litter decomposition and, thus, carbon cycling. Sea salt deposition should generally decline as distance from its marine source increases. For the Amazon, a negative east-west gradient of sea salt availability is assumed as a consequence of the barrier effect of the Andes Mountains for Pacific air masses. However, this generalized pattern may not hold for the tropical mountain rainforest in the Andes of southern Ecuador. To analyse sea salt availability, we investigated the deposition of sodium (Na+) and chloride (Cl-), which are good proxies of sea spray aerosol. Because of the complexity of the terrain and related cloud and rain formation processes, sea salt deposition was analysed from both, rain and occult precipitation (OP) along an altitudinal gradient over a period between 2004 and 2009. To assess the influence of easterly and westerly air masses on the deposition of sodium and chloride over southern Ecuador, sea salt aerosol concentration data from the Monitoring Atmospheric Composition and Climate (MACC) reanalysis data set and back-trajectory statistical methods were combined. Our results, based on deposition time series, show a clear difference in the temporal variation of sodium and chloride concentration and Na+ / Cl- ratio in relation to height and exposure to winds. At higher elevations, sodium and chloride present a higher seasonality and the Na+ / Cl- ratio is closer to that of sea salt. Medium- to long-range sea salt transport exhibited a similar seasonality, which shows the link between our measurements at high elevations and the sea salt synoptic transport. Although the influence of the easterlies was predominant regarding the atmospheric circulation, the statistical analysis of trajectories and hybrid receptor models revealed a stronger impact of the north equatorial Atlantic, Caribbean, and Pacific sea salt sources on the atmospheric sea salt concentration in southern Ecuador. The highest concentration in rain and cloud water was found between September and February when air masses originated from the north equatorial Atlantic, the Caribbean Sea and the equatorial Pacific. Together, these sources accounted for around 82.4 % of the sea salt budget over southern Ecuador.

Examining Environmental Gradients with Remotely Sensed Data - the ESA GlobPermafrost project

NASA Astrophysics Data System (ADS)

Bartsch, Annett; Grosse, Guido; Kääb, Andreas; Westermann, Sebastian; Strozzi, Tazio; Wiesmann, Andreas; Duguay, Claude; Seifert, Frank Martin; Obu, Jaroslav; Nitze, Ingmar; Heim, Birgit; Haas, Antoni; Widhalm, Barbara

2017-04-01

Permafrost cannot be directly detected from space, but many surface features of permafrost terrains and typical periglacial landforms are observable with a variety of EO sensors ranging from very high to medium resolution at various wavelengths. In addition, landscape dynamics associated with permafrost changes and geophysical variables relevant for characterizing the state of permafrost, such as land surface temperature or freeze-thaw state can be observed with space-based Earth Observation. Suitable regions to examine environmental gradients across the Arctic have been defined in a community white paper (Bartsch et al. 2014). These transects have been updated within the ESA DUE GlobPermafrost project. The ESA DUE GlobPermafrost project develops, validates and implements Earth Observation (EO) products to support research communities and international organisations in their work on better understanding permafrost characteristics and dynamics. Prototype product cases will cover different aspects of permafrost by integrating in situ measurements of subsurface properties and surface properties, Earth Observation, and modelling to provide a better understanding of permafrost today. The project will extend local process and permafrost monitoring to broader spatial domains, support permafrost distribution modelling, and help to implement permafrost landscape and feature mapping in a GIS framework. It will also complement active layer and thermal observing networks. Both lowland (latitudinal) and mountain (altitudinal) permafrost issues are addressed. The selected transects and first results will be presented. This includes identified needs from the user requirements survey, a review of existing land surface products available for the Arctic as well as prototypes of GlobPermafrost datasets, and the permafrost information system through which they can be accessed. Bartsch, Annett; Allard, Michel; Biskaborn, Boris Kolumban; Burba, George; Christiansen, Hanne H; Duguay, Claude R; Grosse, Guido; Günther, Frank; Heim, Birgit; Högström, Elin; Kääb, Andreas; Keuper, Frida; Lanckman, Jean-Pierre; Lantuit, Hugues; Lauknes, Tom Rune; Leibman, Marina O; Liu, Lin; Morgenstern, Anne; Necsoiu, Marius; Overduin, Pier Paul; Pope, Allen; Sachs, Torsten; Séjourné, Antoine; Streletskiy, Dmitry A; Strozzi, Tazio; Ullmann, Tobias; Ullrich, Matthias S; Vieira, Goncalo; Widhalm, Barbara (2014): Requirements for monitoring of permafrost in polar regions - A community white paper in response to the WMO Polar Space Task Group (PSTG), Version 4, 2014-10-09. Austrian Polar Research Institute, Vienna, Austria, 20 pp, hdl:10013/epic.45648.d001

How the timberline formed: altitudinal changes in stand structure and dynamics around the timberline in central Japan.

PubMed

Takahashi, Koichi; Hirosawa, Tatsuru; Morishima, Ryohei

2012-05-01

Altitudinal timberlines are thought to move upward by global warming, a crucial topic in ecology. Tall tree species (the conifer Abies mariesii and the deciduous broad-leaved Betula ermanii) dominate the sub-alpine zone between 1600 and 2500 m a.s.l., the timberline, on Mount Norikura in central Japan. Dwarf pine Pinus pumila dominates above the timberline to near the summit (3026 m a.s.l.). This study evaluated how the timberline formed on Mount Norikura by examining altitudinal changes in stand structure and dynamics around the timberline. One hundred and twenty-five plots of 10 m × 10 m were established around the timberline (2350-2600 m a.s.l.). Trunk diameter growth rate during 6 years was examined for A. mariesii, B. ermanii and P. pumila. Mortality during this period and mechanical damage scars on the trunks and branches due to strong wind and snow were examined for A. mariesii only. The density, maximum trunk height and diameter of A. mariesii in plots decreased with altitude. The maximum trunk height of B. ermanii decreased with altitude, but density and maximum trunk diameter did not decrease. In contrast, the density of P. pumila abruptly increased from around the timberline. A strong negative correlation was found between the densities of P. pumila and tall tree species, indicating their interspecific competition. Trunk diameter growth rates of A. mariesii and B. ermanii did not decrease with altitude, suggesting that these two tall tree species can grow at the timberline. The ratio of trees with mechanical damage scars increased with altitude for A. mariesii, a tendency more conspicuous for larger trees. The mortality of larger A. mariesii was also greater at higher altitude. Tall tree species may not increase their trunk height and survive around the timberline because of mechanical damage. This study suggests that the altitudinal location of the timberline is mainly affected by mechanical damage due to strong wind and snow rather than by growth limitation due to low temperature. Therefore, the timberline would not move upward even under global warming if these growth and mortality characteristics do not change for a long time.

Hemoglobin function and allosteric regulation in semi-fossorial rodents (family Sciuridae) with different altitudinal ranges.

PubMed

Revsbech, Inge G; Tufts, Danielle M; Projecto-Garcia, Joana; Moriyama, Hideaki; Weber, Roy E; Storz, Jay F; Fago, Angela

2013-11-15

Semi-fossorial ground squirrels face challenges to respiratory gas transport associated with the chronic hypoxia and hypercapnia of underground burrows, and such challenges are compounded in species that are native to high altitude. During hibernation, such species must also contend with vicissitudes of blood gas concentrations and plasma pH caused by episodic breathing. Here, we report an analysis of hemoglobin (Hb) function in six species of marmotine ground squirrels with different altitudinal distributions. Regardless of their native altitude, all species have high Hb-O2 affinities, mainly due to suppressed sensitivities to allosteric effectors [2,3-diphosphoglycerate (DPG) and chloride ions]. This suppressed anion sensitivity is surprising given that all canonical anion-binding sites are conserved. Two sciurid species, the golden-mantled and thirteen-lined ground squirrel, have Hb-O2 affinities that are characterized by high pH sensitivity and low thermal sensitivity relative to the Hbs of humans and other mammals. The pronounced Bohr effect is surprising in light of highly unusual amino acid substitutions at the C-termini that are known to abolish the Bohr effect in human HbA. Taken together, the high O2 affinity of sciurid Hbs suggests an enhanced capacity for pulmonary O2 loading under hypoxic and hypercapnic conditions, while the large Bohr effect should help to ensure efficient O2 unloading in tissue capillaries. In spite of the relatively low thermal sensitivities of the sciurid Hbs, our results indicate that the effect of hypothermia on Hb oxygenation is the main factor contributing to the increased blood-O2 affinity in hibernating ground squirrels.

Physicochemical properties and carbon density of alpine sod layer with their variation across habitat gradients in the Zoige Plateau

NASA Astrophysics Data System (ADS)

Peixi, Su; Zijuan, Zhou; Rui, Shi; tingting, Xie

2017-04-01

The alpine sod layer is a soft, tough and resistant to shifting surface soil layer under the formation of the natural vegetation in the plateau cold region, understanding its ecological function is a prerequisite to promote grass and animal husbandry production for recuperation and protection, and the active use of project construction. Based on the extensive investigation on the alpine vegetation of the Zoige Plateau in the Eastern Qinghai-Tibetan Plateau of China, set up moisture gradient community sample plots: swamp, degraded swamp, swampy meadow, wet meadow, dry meadow and degraded meadow, and the elevation gradient community sample plots: subalpine meadow, subalpine shrub meadow, alpine shrub meadow and alpine meadow were set up. The sod layer bulk density, soil particle composition and soil organic carbon (SOC) content of different types of community plots were analyzed and to compare its carbon sequestration capacity on the moisture and elevation gradients. The results showed that the average thickness of the sod layer was 30 cm, the bulk density of the swamp was the smallest, and the SOC content was above 300 g/kg. The bulk density of degraded meadow was the highest while its SOC content was decreased significantly. The SOC density of sod layer in different communities was between 10 and 24 kg C/m2, and decreased with the decreasing of soil water availability, and meadow degradation significantly decreased the soil organic carbon storage in sod layer. The sod layer SOC density of alpine shrub meadow was 15% higher than that of meadow on the altitudinal gradient. It was concluded that the mass water content threshold value for maintaining the sod layer stable is 30%. In the degraded succession of alpine vegetation from swamp to meadow, the bulk density and compactness of sod layer became larger, while the organic carbon content, carbon density and carbon storage decreased. The higher the gravel content of swamp, the more easily degraded, and the higher the sand content of the meadow, the more easily degraded. Shrub meadow had higher carbon sequestration capacity than that of meadow, but the productive function of shrub meadow was lower. Keeping the sustainable development of grassland productivity and maintaining the carbon sequestration ecological function, it is necessary to prevent the degradation of the sod layer, and restrain the succession from meadow to scrub meadow. Key Words: surface soil layer, soil organic carbon, carbon density, alpine vegetation, Zoige Plateau

Controls on soil solution nitrogen along an altitudinal gradient in the Scottish uplands

NASA Astrophysics Data System (ADS)

Jackson-Blake, L.; Helliwell, R. C.; Britton, A. J.; Gibbs, S.; Coull, M. C.; Dawson, L.

2012-04-01

Nitrogen (N) deposition continues to threaten upland ecosystems, contributing to acidification, eutrophication and biodiversity loss. We present results from a monitoring study aimed at investigating the fate of this deposited N within a relatively pristine catchment in the Cairngorm Mountains (Scotland). Six sites were established along an elevation gradient (486 - 908 m) spanning the key habitats of temperate maritime uplands. Bulk deposition chemistry, soil carbon content, soil solution chemistry, soil temperature and soil moisture content were monitored over a 5 year period, making this the first study of its kind in a maritime Alpine environment. Results were used to assess spatial variability in soil solution N and to investigate the factors and processes driving this variability. Highest soil solution inorganic N concentrations were found in the alpine soils at the top of the hillslope. Soil carbon stock, dissolved organic carbon concentration and factors representing site hydrology were the best predictors of nitrate concentration. These factors act as proxies for changing net biological uptake and soil/water contact time, and support the hypothesis that spatial variations in soil solution nitrate are controlled by habitat N retention capacity. Soil percent carbon was a better predictor of soil solution N concentration than mass of carbon. Ammonium was less affected by soil hydrology than nitrate and showed the effects of net mineralization inputs, particularly at Racomitrium heath and peaty sites. We hypothesize that high ammonium concentrations at the Racomitrium heath are related to the mineralization of microbial cell tissue during times of stress, largely in the absence of plant uptake. Due to the spatial heterogeneity in N leaching potential, a fine-scale approach to assessing surface water vulnerability to N leaching is recommended over the broad scale, critical loads approach currently in use, particularly for sensitive areas.

Is the number and size of scales in Liolaemus lizards driven by climate?

PubMed

José Tulli, María; Cruz, Félix B

2018-05-03

Ectothermic vertebrates are sensitive to thermal fluctuations in the environments where they occur. To buffer these fluctuations, ectotherms use different strategies, including the integument, which is a barrier that minimizes temperature exchange between the inner body and the surrounding air. In lizards, this barrier is constituted by keratinized scales of variable size, shape and texture, and its main function is protection, water loss avoidance and thermoregulation. The size of scales in lizards has been proposed to vary in relation to climatic gradients; however, it has also been observed that in some groups of Iguanian lizards could be related to phylogeny. Thus, here, we studied the area and number of scales (dorsal and ventral) of 61 species of Liolaemus lizards distributed in a broad latitudinal and altitudinal gradient to determine the nature of the variation of the scales with climate, and found that the number and size of scales are related to climatic variables, such as temperature and geographical variables as altitude. The evolutionary process that better explained how these morphological variables evolved was the Ornstein-Uhlenbeck model. The number of scales seemed to be related to common ancestry, whereas dorsal and ventral scale areas seemed to vary as a consequence of ecological traits. In fact, the ventral area is less exposed to climate conditions such as ultraviolet radiation or wind and is thus under less pressure to change in response to alterations in external conditions. It is possible that scale ornamentation such as keels and granulosity may bring some more information in this regard. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

The contribution of runoff to recharge rates in a semiarid to subhumid carbonated aquifer. A case study from the Sierra de Gador, SE Spain.

NASA Astrophysics Data System (ADS)

Frot, E.; Contreras, S.; Alcala, F. J.; Solé, A.; van Wesemael, B.

2009-04-01

Two general pathways exist for recharge in carbonated aquifers: i) diffuse percolation from the base of the soil profile and ii) concentrated infiltration of surface water in favourable zones such as ephemeral stream beds and widened cracks in partly dissolved limestone. It has been shown that for large semi arid regions diffuse percolation can be assessed from the water balance i.e. the difference in precipitation and evapotranspiration. Recently, methods have been developed to assess the water balance at the regional scale based on the spatial distribution of rainfall and vegetation indices, the latter as a proxy for evapotranspiration. Concentration of surface water occurs during moderate to heavy rainfall events as a result of runoff generation from impermeable or low permeable areas, or partially controlled by slope when permeable rock outcrops. It has been shown that the large carbonate aquifer system of the Sierra de Gador, underlayered by the Campo de Dalias coastal plain, is fed preferentially during storms with a return period of more than 1-5 years. However, as a result of the volume of the aquifer, its unknown response time and the infrequent occurrence of such events, no evaluation of the relative contribution of diffuse versus concentrated recharge can be made. Therefore, different methodological approaches are applied to assess the role that both type of recharge mechanisms (diffuse and concentrated) have on the water yield of a single semiarid catchment which is drained by a regional spring of Celin. The study catchment covers a surface of c.26 km² ranging from the footslopes at 580 m a.s.l. to the summit of the Sierra de Gador at 2200 m a.s.l. The average potential recharge varies from more than 250 mm/year in summit areas to less than 50 mm/year in the bottom of the range. Runoff will be calculated using a spatially distributed rainfall/runoff model that was calibrated on water harvesting systems draining the representative combination of vegetation, rock outcrop and soil types within the Sierra de Gador. An altitudinal gradient of runoff to concavities and stream beds will be calculated for moderate storms (return period 1 year) under wet, normal and dry antecedent moisture conditions in order to estimate concentrated recharge. Furthermore, gradients as a result of diffuse recharge based on the spatial modelling of the water balance will be calculated based on the method of Contreras et al. (2008). Both gradients will be checked with those obtained by isotopic techniques, focussed to know the source of recharge, and by conservative chemical balances to quantify diffuse recharge rates in local springs at several altitudes. Under steady-state conditions, the bulk solutes mass discharged in Celin spring integrates flow mass derived from diffuse recharge by rainfall at several altitudes plus mass flow from concentrated recharge by runoff. These results give more insights about the relative contribution of both pathways to recharge in semiarid carbonate aquifers. An understanding of the relative contribution of these pathways along altitude is essential for implementing measures to increase recharge artificially.

Lingual and fusiform gyri in visual processing: a clinico-pathologic study of superior altitudinal hemianopia.

PubMed Central

Bogousslavsky, J; Miklossy, J; Deruaz, J P; Assal, G; Regli, F

1987-01-01

A macular-sparing superior altitudinal hemianopia with no visuo-psychic disturbance, except impaired visual learning, was associated with bilateral ischaemic necrosis of the lingual gyrus and only partial involvement of the fusiform gyrus on the left side. It is suggested that bilateral destruction of the lingual gyrus alone is not sufficient to affect complex visual processing. The fusiform gyrus probably has a critical role in colour integration, visuo-spatial processing, facial recognition and corresponding visual imagery. Involvement of the occipitotemporal projection system deep to the lingual gyri probably explained visual memory dysfunction, by a visuo-limbic disconnection. Impaired verbal memory may have been due to posterior involvement of the parahippocampal gyrus and underlying white matter, which may have disconnected the intact speech areas from the left medial temporal structures. Images PMID:3585386

The biological activity of chernozems in the Central Caucasus Mountains (Terskii variant of altitudinal zonality), Kabardino-Balkaria

NASA Astrophysics Data System (ADS)

Gedgafova, F. V.; Uligova, T. S.; Gorobtsova, O. N.; Tembotov, R. Kh.

2015-12-01

Some parameters of the biological activity (humus content; activity of hydrolytic enzymes invertase, phosphatase, urease; and the intensity of carbon dioxide emission) were studied in the chernozems of agrocenoses and native biogeocenoses in the foothills of the Caucasus Mountains representing the Terskii variant of the altitudinal zonality. The statistically significant differences were revealed between the relevant characteristics of the soils of the agrocenoses and of the native biogeocenoses. The integral index of the ecological-biological state of the soils was used to estimate changes in the biological activity of the arable chernozems. The 40-60% decrease of this index in the cultivated chernozems testified to their degradation with a decrease in fertility and the disturbance of ecological functions as compared to these characteristics in the virgin chernozems.

Altitudinal and Seasonal Variation in Drosophila Species on Mount Japfu of Nagaland, a Sub-Himalayan Hilly State of India

PubMed Central

Achumi, Bovito; Hegde, Shridhar N.; Lal, Pardeshi; Yenisetti, Sarat Chandra

2013-01-01

Drosophila (L.) (Diptera: Drosophilidae) has richly contributed to the understanding of patterns of inheritance, variation, speciation, and evolution. Drosophila, with its cosmopolitan nature and complexities in species compositions, is an excellent model for studying the eco-distributional patterns of various species. This study analyzed the altitudinal and seasonal variation in Drosophila species of Mount Japfu in Nagaland, a sub-Himalayan hilly state of northeast India, over the course of one year. A total of 4,680 Drosophila flies belonging to 19 species of 4 subgenera were collected at altitudes of 1500, 1800, 2100, 2400, and 2700 m a.s.l. The subgenus Sophophora Sturtevant was predominant, with 10 species, followed by subgenus Drosophila, with 4 species. Subgenus Dorsilopha and subgenus Scaptodrosophila were represented by 1 species each. The remaining 3 species were not identified. Cluster analysis and constancy methods were used to analyze the species occurrence qualitatively. Altitudinal changes in the population densities and relative abundances of the different species at different seasons were also studied. The diversity of the Drosophila community was assessed by applying Simpson's diversity index. At 1800 m a.s.l., the Simpson's index was low (0.09301), suggesting high Drosophila diversity at this altitude. The density of Drosophila changed significantly during different seasons (F = 26.72; df = 2; p < 0.0001). The results suggest the distributional pattern of a species or related group of species was uneven in space and time. PMID:24773245

87Sr/86Sr in recent accumulations of calcium sulfate on landscapes of hyperarid settings: A bimodal altitudinal dependence for northern Chile (19.5°S-21.5°S)

NASA Astrophysics Data System (ADS)

Cosentino, N. J.; Jordan, T. E.; Derry, L. A.; Morgan, J. P.

2015-12-01

An elevation-dependent relationship of the 87Sr/86Sr ratio of Holocene surface accumulations of sulfate salts is demonstrated for a continental margin hyperarid setting. In the Atacama Desert of northern Chile, gypsum and anhydrite of multiple origins exist widely on superficial materials that originated during the last 10,000 years. An important source of calcium sulfate is from offshore-generated stratocumulus clouds that are advected onto the continent, where they generate fog that transfers water droplets to the ground surface which, upon evaporation, leaves calcium sulfate crystals. Meteorological measurements of the cloud base and top altitudes average ˜400 m and ˜1100 m above sea level (masl), respectively. The seawater ratio of 87Sr/86Sr (0.70917) is distinctively higher than that reported for weathered mean Andean rock (less than 0.70750). Samples of 28 modern surface salt accumulations for locations between 200 and 2950 masl and between ˜19°30' and ˜21°30'S verify that 87Sr/86Sr varies as a function of site altitude. Sites below 1075 masl and above 225 masl display calcium sulfate 87Sr/86Sr of mean value 0.70807 ± 0.00004, while the ratio outside this altitudinal domain is 0.70746 ± 0.00010. Thus, the 87Sr/86Sr ratio of Holocene salt accumulations differentiates two altitudinal domains.

Geographic variation in the response of Culex pipiens life history traits to temperature.

PubMed

Ruybal, Jordan E; Kramer, Laura D; Kilpatrick, A Marm

2016-02-29

Climate change is predicted to alter the transmission of many vector-borne pathogens. The quantitative impact of climate change is usually estimated by measuring the temperature-performance relationships for a single population of vectors, and then mapping this relationship across a range of temperatures or locations. However, life history traits of different populations often differ significantly. Specifically, performance across a range of temperatures is likely to vary due to local adaptation to temperature and other factors. This variation can cause spatial variation in pathogen transmission and will influence the impact of climate change on the transmission of vector-borne pathogens. We quantified variation in life history traits for four populations of Culex pipiens (Linnaeus) mosquitoes. The populations were distributed along altitudinal and latitudinal gradients in the eastern United States that spanned ~3 °C in mean summer temperature, which is similar to the magnitude of global warming expected in the next 3-5 decades. We measured larval and adult survival, development rate, and biting rate at six temperatures between 16 and 35 °C, in a common garden experiment. Temperature had strong and consistent non-linear effects on all four life history traits for all four populations. Adult female development time decreased monotonically with increasing temperature, with the largest decrease at cold temperatures. Daily juvenile and adult female survival also decreased with increasing temperature, but the largest decrease occurred at higher temperatures. There was significant among-population variation in the thermal response curves for the four life history traits across the four populations, with larval survival, adult survival, and development rate varying up to 45, 79, and 84 % among populations, respectively. However, variation was not correlated with local temperatures and thus did not support the local thermal adaptation hypothesis. These results suggest that the impact of climate change on vector-borne disease will be more variable than previous predictions, and our data provide an estimate of this uncertainty. In addition, the variation among populations that we observed will shape the response of vectors to changing climates.

Temperature Inversions and Permafrost Distribution in a Mountain Valley: Preliminary Results From Wolf Creek, Yukon Territory, Canada

NASA Astrophysics Data System (ADS)

Lewkowicz, A. G.; Smith, K. M.

2004-12-01

The BTS (Basal Temperature of Snow) method to predict permafrost probability in mountain basins uses elevation as an easily available and spatially distributed independent variable. The elevation coefficient in the BTS regression model is, in effect, a substitute for ground temperature lapse rates. Previous work in Wolf Creek (60° 8'N 135° W), a mountain basin near Whitehorse, has shown that the model breaks down in a mid-elevation valley (1250 m asl) where actual permafrost probability is roughly twice that predicted by the model (60% vs. 20-30%). The existence of a double tree-line at the site suggested that air temperature inversions might be the cause of this inaccuracy (Lewkowicz and Ednie, 2004). This paper reports on a first year (08/2003-08/2004) of hourly air and ground temperature data collected along an altitudinal transect within the valley in upper Wolf Creek. Measurements were made at sites located 4, 8, 22, 82 and 162 m above the valley floor. Air temperature inversions between the lowest and highest measurement points occurred 42% of the time and in all months, but were most frequent and intense in winter (>60% of December and January) and least frequent in September (<25% of time). They generally developed after sunset and reached a maximum amplitude before sunrise. Only 11 inversions that lasted through more than one day occurred during the year, and only from October to February. The longest continuous duration was 145 h while the greatest inversion magnitude measured over the 160 m transect was 19° C. Ground surface temperatures are more difficult to interpret because of differences in soils and vegetation cover along the transect and the effects of seasonal snow cover. In many cases, however, air temperature inversions are not duplicated in the ground temperature record. Nevertheless, the annual altitudinal ground temperature gradient is much lower than would be expected from a standard atmospheric lapse rate, suggesting that the inversions do have an important impact on permafrost distribution at this site. More generally, therefore, it appears probable that any reduction in inversion frequency resulting from a more vigorous atmospheric circulation in the context of future climate change, would have a significant effect on permafrost distribution in mountain basins.

Inter-hemispheric asymmetry of Pedersen conductance

NASA Astrophysics Data System (ADS)

Deng, Y.; Lu, Y.; Sheng, C.; Yue, X.

2015-12-01

Ionospheric conductance is very important to the magnetosphere-ionosphere coupling in the high latitude region, since it connects the polar cap potential with the currents. Meanwhile, the altitudinal distribution of Pederson conductance gives us a rough idea about the altitudinal distribution of Joule heating at high latitudes. Based on the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites observations of electron density profiles from 2009-2014, Pedersen conductivity has been calculated. A climatologic study of the height-integrated Pedersen conductivities in both E (100-150 km) and F (150-600 km) regions and their ratio in different seasons, solar and geomagnetic conditions have been conducted. A significant inter-hemispheric asymmetry is identified in the seasonal variation. Meanwhile, the conductance in both regions and the conductance ratio show a strong dependence on F10.7 and Ap indices. This result will strongly help our understanding of the inter-hemispheric difference in the high-latitude electrodynamics.

Can variation in risk of nest predation explain altitudinal migration in tropical birds?

PubMed

Boyle, W Alice

2008-03-01

Migration is among the best studied of animal behaviors, yet few empirical studies have tested hypotheses explaining the ultimate causes of these cyclical annual movements. Fretwell's (1980) hypothesis predicts that if nest predation explains why many tropical birds migrate uphill to breed, then predation risk must be negatively associated with elevation. Data from 385 artificial nests spanning 2,740 m of elevation on the Atlantic slope of Costa Rica show an overall decline in predation with increasing elevation. However, nest predation risk was highest at intermediate elevations (500-650 m), not at lowest elevations. The proportion of nests depredated by different types of predators differed among elevations. These results imply that over half of the altitudinal migrant bird species in this region migrate to safer breeding areas than their non-breeding areas, suggesting that variation in nest predation risk could be an important benefit of uphill migrations of many species.

Indigenous and Invasive Fruit Fly Diversity along an Altitudinal Transect in Eastern Central Tanzania

PubMed Central

Geurts, Katrien; Mwatawala, Maulid; De Meyer, Marc

2012-01-01

The relative abundance of indigenous and invasive frugivorous fruit flies (Diptera: Tephritidae) was evaluated spatially and temporally along an altitudinal transect between 581–1650 m in the Uluguru Mountains near Morogoro, Tanzania. The polyphagous invasive fruit fly Bactrocera invadens Drew, Tsuruta, and White and the indigenous fruit fly Ceratitis rosa Karsch show a similar temporal pattern, but are largely separated spatially, with B. invadens being abundant at lower elevation and C. rosa predominant at higher elevation. The polyphagous indigenous C. cosyra (Walker) coincides with B. invadens but shows an inverse temporal pattern. The cucurbit feeders B. cucurbitae (Coquillett) and Dacus bivittatus (Bigot) show a similar temporal pattern, but the former is restricted to lower elevations. Host availability and climatic differences seem to be the determining factors to explain the differences in occurrence and abundance in time and space. PMID:22935017

Faster poleward range shifts in moths with more variable colour patterns

PubMed Central

Forsman, Anders; Betzholtz, Per-Eric; Franzén, Markus

2016-01-01

Range shifts have been documented in many organisms, and climate change has been implicated as a contributing driver of latitudinal and altitudinal range modifications. However, little is known about what species trait(s) allow for faster environmental tracking and improved capacity for distribution expansions. We used data for 416 species of moths, and show that range limits in Sweden have shifted to the north by on average 52.4 km per decade between 1973 and 2014. When also including non-expanding species, average expansion rate was 23.2 km per decade. The rate of boundary shifts increased with increasing levels of inter-individual variation in colour patterns and decreased with increasing latitude. The association with colour patterns indicate that variation in this functionally important trait enables species to cope with novel and changing conditions. Northern range limits also increased with average abundance and decreased with increasing year-to-year abundance fluctuations, implicating production of dispersers as a driver of range dynamics. Studies of terrestrial animals show that rates of poleward shifts differ between taxonomic groups, increase over time, and depend on study duration and latitude. Knowledge of how distribution shifts change with time, location, and species characteristics may improve projections of responses to climate change and aid the protection of biodiversity. PMID:27808116

Faster poleward range shifts in moths with more variable colour patterns

NASA Astrophysics Data System (ADS)

Forsman, Anders; Betzholtz, Per-Eric; Franzén, Markus

2016-11-01

Range shifts have been documented in many organisms, and climate change has been implicated as a contributing driver of latitudinal and altitudinal range modifications. However, little is known about what species trait(s) allow for faster environmental tracking and improved capacity for distribution expansions. We used data for 416 species of moths, and show that range limits in Sweden have shifted to the north by on average 52.4 km per decade between 1973 and 2014. When also including non-expanding species, average expansion rate was 23.2 km per decade. The rate of boundary shifts increased with increasing levels of inter-individual variation in colour patterns and decreased with increasing latitude. The association with colour patterns indicate that variation in this functionally important trait enables species to cope with novel and changing conditions. Northern range limits also increased with average abundance and decreased with increasing year-to-year abundance fluctuations, implicating production of dispersers as a driver of range dynamics. Studies of terrestrial animals show that rates of poleward shifts differ between taxonomic groups, increase over time, and depend on study duration and latitude. Knowledge of how distribution shifts change with time, location, and species characteristics may improve projections of responses to climate change and aid the protection of biodiversity.

Diversity and altitudinal distribution of phlebotomine sand flies (Diptera: Psychodidae) in visceral leishmaniasis endemic areas of northwest Ethiopia.

PubMed

Yared, Solomon; Gebresilassie, Araya; Akililu, Essayas; Deribe, Kebede; Balkew, Meshesha; Warburg, Alon; Hailu, Asrat; Gebre-Michael, Teshome

2017-12-01

The Leishmaniases are caused by the protozoan parasites of the genus Leishmania and are transmitted to humans by the bite of infected female phlebotomine sand flies. Both visceral and cutaneous leishmaniases are widely distributed in different parts of Ethiopia. The aim of this study was to determine the diversity and altitudinal distribution of phlebotomine sand flies from Kafta Humera to Gondar town in northwest Ethiopia. Seven localities were selected with distinct altitudinal variations between 550m above sea level (m a.s.l) and 2300m a.s.l. In each locality, sand flies were collected using standard CDC light traps and sticky traps during the active sand fly season from December 2012 to May 2013. Shannon-Weiner species diversity index and Jaccard's coefficient were used to estimate species diversity and similarity between altitudes and localities, respectively. A total of 89,044 sand flies (41,798 males and 47, 246 females) were collected from the seven localities/towns throughout the study period. Twenty-two species belonging to 11 species in the genus Phlebotomus and 11 species in the genus Sergentomyia were documented. Of these, Sergentomyia clydei (25.87%), S. schwetzi (25.21%), S. africana (24.65%), S. bedfordi (8.89%), Phlebotomus orientalis (6.43%), and S. antennata (4.8%) were the most prevalent species. The remaining 10 Phlebotomus species and six Sergentomyia were less frequent catches. In CDC light trap and sticky trap, higher species diversity and richness for both male and female sand flies was observed at low altitude ranging from 550 to 699m a.s.l in Adebay village in Kafta Humera district whereas low species richness and high evenness of both sexes were also observed in an altitude 1950-2300m a.s.l. The results revealed that the presence of leishmaniasis vectors such as P. orientalis, P. longipes, P. papatasi, and P. duboscqi in different altitudes in northwest Ethiopia. P. orientalis a vector of L. donovani, occurred between altitude 500-1100m a.s.l, the area could be at high risk of VL. P. longipes a vector of L. aethiopica, was recorded in the highland area in Tikil-Dingay and Gondar town, implicating the possibility of CL transmission. Hence, further investigation into vector competence in relation to leishmaniasis (VL and CL) in the region is very vital. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

A General, Synthetic Model for Predicting Biodiversity Gradients from Environmental Geometry.

PubMed

Gross, Kevin; Snyder-Beattie, Andrew

2016-10-01

Latitudinal and elevational biodiversity gradients fascinate ecologists, and have inspired dozens of explanations. The geometry of the abiotic environment is sometimes thought to contribute to these gradients, yet evaluations of geometric explanations are limited by a fragmented understanding of the diversity patterns they predict. This article presents a mathematical model that synthesizes multiple pathways by which environmental geometry can drive diversity gradients. The model characterizes species ranges by their environmental niches and limits on range sizes and places those ranges onto the simplified geometries of a sphere or cone. The model predicts nuanced and realistic species-richness gradients, including latitudinal diversity gradients with tropical plateaus and mid-latitude inflection points and elevational diversity gradients with low-elevation diversity maxima. The model also illustrates the importance of a mid-environment effect that augments species richness at locations with intermediate environments. Model predictions match multiple empirical biodiversity gradients, depend on ecological traits in a testable fashion, and formally synthesize elements of several geometric models. Together, these results suggest that previous assessments of geometric hypotheses should be reconsidered and that environmental geometry may play a deeper role in driving biodiversity gradients than is currently appreciated.

Wide-range stiffness gradient PVA/HA hydrogel to investigate stem cell differentiation behavior.

PubMed

Oh, Se Heang; An, Dan Bi; Kim, Tae Ho; Lee, Jin Ho

2016-04-15

Although stiffness-controllable substrates have been developed to investigate the effect of stiffness on cell behavior and function, the use of separate substrates with different degrees of stiffness, substrates with a narrow range stiffness gradient, toxicity of residues, different surface composition, complex fabrication procedures/devices, and low cell adhesion are still considered as hurdles of conventional techniques. In this study, a cylindrical polyvinyl alcohol (PVA)/hyaluronic acid (HA) hydrogel with a wide-range stiffness gradient (between ∼20kPa and ∼200kPa) and cell adhesiveness was prepared by a liquid nitrogen (LN2)-contacting gradual freezing-thawing method that does not use any additives or specific devices to produce the stiffness gradient hydrogel. From an in vitro cell culture using the stiffness gradient PVA/HA hydrogel, it was observed that human bone marrow mesenchymal stem cells have favorable stiffness ranges for induction of differentiation into specific cell types (∼20kPa for nerve cell, ∼40kPa for muscle cell, ∼80kPa for chondrocyte, and ∼190kPa for osteoblast). The PVA/HA hydrogel with a wide range of stiffness spectrum can be a useful tool for basic studies related with the stem cell differentiation, cell reprogramming, cell migration, and tissue regeneration in terms of substrate stiffness. It is postulated that the stiffness of the extracellular matrix influences cell behavior. To prove this concept, various techniques to prepare substrates with a stiffness gradient have been developed. However, the narrow ranges of stiffness gradient and complex fabrication procedures/devices are still remained as limitations. Herein, we develop a substrate (hydrogel) with a wide-range stiffness gradient using a gradual freezing-thawing method which does not need specific devices to produce a stiffness gradient hydrogel. From cell culture experiments using the hydrogel, it is observed that human bone marrow mesenchymal stem cells have favorable stiffness ranges for induction of differentiation into specific cell types (∼20kPa for nerve, ∼40kPa for muscle, ∼80kPa for cartilage, and ∼190kPa for bone in our hydrogel system). Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

The ecology of climate change and infectious diseases

USGS Publications Warehouse

Lafferty, Kevin D.

2009-01-01

The projected global increase in the distribution and prevalence of infectious diseases with climate change suggests a pending societal crisis. The subject is increasingly attracting the attention of health professionals and climate-change scientists, particularly with respect to malaria and other vector-transmitted human diseases. The result has been the emergence of a crisis discipline, reminiscent of the early phases of conservation biology. Latitudinal, altitudinal, seasonal, and interannual associations between climate and disease along with historical and experimental evidence suggest that climate, along with many other factors, can affect infectious diseases in a nonlinear fashion. However, although the globe is significantly warmer than it was a century ago, there is little evidence that climate change has already favored infectious diseases. While initial projections suggested dramatic future increases in the geographic range of infectious diseases, recent models predict range shifts in disease distributions, with little net increase in area. Many factors can affect infectious disease, and some may overshadow the effects of climate.

Data documenting the potential distribution of Aedes aegypti in the center of Veracruz, Mexico.

PubMed

Estrada-Contreras, Israel; Sandoval-Ruiz, César A; Mendoza-Palmero, Fredy S; Ibáñez-Bernal, Sergio; Equihua, Miguel; Benítez, Griselda

2017-02-01

The data presented in this article are related to the research article entitled "Establishment of Aedes aegypti (L.) in mountainous regions in Mexico: Increasing number of population at risk of mosquito-borne disease and future climate conditions" (M. Equihua, S. Ibáñez-Bernal, G. Benítez, I. Estrada-Contreras, C.A. Sandoval-Ruiz, F.S. Mendoza-Palmero, 2016) [1]. This article provides presence records in shapefile format used to generate maps of potential distribution of Aedes aegypti with different climate change scenarios as well as each of the maps obtained in raster format. In addition, tables with values of potential distribution of the vector as well as the average values of probability of presence including data of the mosquito incidence along the altitudinal range.

Punctuated invasion of water, ice, snow and terrestrial ecozones by segmented worms (Oligochaeta: Enchytraeidae: Mesenchytraeus).

PubMed

Lang, Shirley A; Saglam, Naim; Kawash, Joseph; Shain, Daniel H

2017-10-11

Segmented worms (Annelida) are among the most successful animal inhabitants of extreme environments worldwide. An unusual group of enchytraeid oligochaetes of genus Mesenchytraeus are abundant in the Pacific northwestern region of North America and occupy geographically proximal ecozones ranging from low elevation rainforests and waterways to high altitude glaciers. Along this altitudinal transect, Mesenchytraeus representatives from disparate habitat types were collected and subjected to deep mitochondrial and nuclear phylogenetic analyses. Our data identify significant topological discordance among gene trees, and near equivalent interspecific divergence levels indicative of a rapid radiation event. Collectively, our results identify a Mesenchytraeus 'explosion' coincident with mountain building in the Pacific northwestern region that gave rise to closely related aquatic, ice, snow and terrestrial worms. © 2017 The Author(s).

Hemoglobin function and allosteric regulation in semi-fossorial rodents (family Sciuridae) with different altitudinal ranges

PubMed Central

Revsbech, Inge G.; Tufts, Danielle M.; Projecto-Garcia, Joana; Moriyama, Hideaki; Weber, Roy E.; Storz, Jay F.; Fago, Angela

2013-01-01

SUMMARY Semi-fossorial ground squirrels face challenges to respiratory gas transport associated with the chronic hypoxia and hypercapnia of underground burrows, and such challenges are compounded in species that are native to high altitude. During hibernation, such species must also contend with vicissitudes of blood gas concentrations and plasma pH caused by episodic breathing. Here, we report an analysis of hemoglobin (Hb) function in six species of marmotine ground squirrels with different altitudinal distributions. Regardless of their native altitude, all species have high Hb–O2 affinities, mainly due to suppressed sensitivities to allosteric effectors [2,3-diphosphoglycerate (DPG) and chloride ions]. This suppressed anion sensitivity is surprising given that all canonical anion-binding sites are conserved. Two sciurid species, the golden-mantled and thirteen-lined ground squirrel, have Hb–O2 affinities that are characterized by high pH sensitivity and low thermal sensitivity relative to the Hbs of humans and other mammals. The pronounced Bohr effect is surprising in light of highly unusual amino acid substitutions at the C-termini that are known to abolish the Bohr effect in human HbA. Taken together, the high O2 affinity of sciurid Hbs suggests an enhanced capacity for pulmonary O2 loading under hypoxic and hypercapnic conditions, while the large Bohr effect should help to ensure efficient O2 unloading in tissue capillaries. In spite of the relatively low thermal sensitivities of the sciurid Hbs, our results indicate that the effect of hypothermia on Hb oxygenation is the main factor contributing to the increased blood–O2 affinity in hibernating ground squirrels. PMID:24172889

From frugivore to folivore: Altitudinal variations in the diet and feeding ecology of the Bioko Island drill (Mandrillus leucophaeus poensis).

PubMed

Owens, Jacob R; Honarvar, Shaya; Nessel, Mark; Hearn, Gail W

2015-12-01

Variation in the quality and availability of food resources can greatly influence the ecology, behavior, and conservation of wild primates. We studied the influence of altitudinal differences in resource availability on diet in wild drill monkeys (Mandrillus leucophaeus poensis) on Bioko Island, Equatorial Guinea. We compared fecal samples (n = 234) collected across three consecutive dry seasons for drills living in lowland (0-300 m asl) forest with nearby (18 km distance) drills living in montane forest (500-1000 m asl) in the Gran Caldera Southern Highlands Scientific Reserve. Lowland forest drills had a frugivorous diet very similar to that reported from studies on nearby mainland drills (M. l. leucophaeus) and mandrills (M. sphinx), with fruits comprising 90% of their dried fecal samples. However drills living in montane forest had a more folivorous diet, with herbaceous pith, leaves and fungi comprising 74% of their dried fecal samples and fruit becoming a minor component (24%). Furthermore, a dietary preference index indicated that the differences in the proportion of fruit and fibrous vegetation in the diets of lowland compared to montane drills was not simply a result of relative availability. Montane drills were actively consuming a higher mass of the available fruits and fibrous vegetation, a condition reflected in the greater mass of their fresh feces. Our results demonstrate the unexpected flexibility and complexity of dietary choices of this endangered species in two adjacent habitat types, a comparison of considerable importance for many other limited-range species faced with habitat loss and climate change. © 2015 Wiley Periodicals, Inc.

Differences between Non-arteritic Anterior Ischemic Optic Neuropathy and Open Angle Glaucoma with Altitudinal Visual Field Defect.

PubMed

Han, Sangyoun; Jung, Jong Jin; Kim, Ungsoo Samuel

2015-12-01

To investigate the differences in retinal nerve fiber layer (RNFL) change and optic nerve head parameters between non-arteritic anterior ischemic optic neuropathy (NAION) and open angle glaucoma (OAG) with altitudinal visual field defect. Seventeen NAION patients and 26 OAG patients were enrolled prospectively. The standard visual field indices (mean deviation, pattern standard deviation) were obtained from the Humphrey visual field test and differences between the two groups were analyzed. Cirrus HD-OCT parameters were used, including optic disc head analysis, average RNFL thickness, and RNFL thickness of each quadrant. The mean deviation and pattern standard deviation were not significantly different between the groups. In the affected eye, although the disc area was similar between the two groups (2.00 ± 0.32 and 1.99 ± 0.33 mm(2), p = 0.586), the rim area of the OAG group was smaller than that of the NAION group (1.26 ± 0.56 and 0.61 ± 0.15 mm(2), respectively, p < 0.001). RNFL asymmetry was not different between the two groups (p = 0.265), but the inferior RNFL thickness of both the affected and unaffected eyes were less in the OAG group than in the NAION group. In the analysis of optic disc morphology, both affected and unaffected eyes showed significant differences between two groups. To differentiate NAION from OAG in eyes with altitudinal visual field defects, optic disc head analysis of not only the affected eye, but also the unaffected eye, by using spectral domain optical coherence tomography may be helpful.

Ecological status and traditional knowledge of medicinal plants in Kedarnath Wildlife Sanctuary of Garhwal Himalaya, India.

PubMed

Bhat, Jahangeer A; Kumar, Munesh; Bussmann, Rainer W

2013-01-02

Himalayan forests are the most important source of medicinal plants and with useful species for the local people. Kedarnath Wildlife Sanctuary (KWLS) is situated in the interior part of the Garhwal Himalayan region. The presented study was carried out in Madhmeshwar area of KWLS for the ecological status of medicinal plants and further focused on the ethnomedicinal uses of these plants in the study area. Ecological information about ethnomedicinal plants were collected using random quadrats in a random sampling technique along an altitudinal gradient in the KWLS. Information on medicinal properties of plants encountered in the present study was generated by questionnaire survey and was also compared with relevant literature. A total of 152 medicinally important plant species were reported, in which 103 were found herbs, 32 shrubs and 17 were tree species which represented 123 genera of 61 families. A total of 18 plant species fell into the rare, endangered (critically endangered) and vulnerable status categories. The present study documented the traditional uses of medicinal plants, their ecological status and importance of these plants in the largest protected area of Garhwal Himalaya. This study can serve as baseline information on medicinal plants and could be helpful to further strengthen the conservation of this important resource.

Extrapolating from local ecological processes to genus-wide patterns in colour polymorphism in South African Protea

PubMed Central

Carlson, Jane E.; Holsinger, Kent E.

2015-01-01

Polymorphic traits are central to many fundamental discoveries in evolution, yet why they are found in some species and not others remains poorly understood. We use the African genus Protea—within which more than 40% of species have co-occurring pink and white floral colour morphs—to ask whether convergent evolution and ecological similarity could explain the genus-wide pattern of polymorphism. First, we identified environmental correlates of pink morph frequency across 28 populations of four species. Second, we determined whether the same correlates could predict species-level polymorphism and monomorphism across 31 species. We found that pink morph frequency increased with elevation in Protea repens and three section Exsertae species, increased eastward in P. repens, and increased with seed predation intensity in section Exsertae. For cross-species comparisons, populations of monomorphic pink species occurred at higher elevations than populations of monomorphic white species, and 18 polymorphic species spanned broader elevational gradients than 13 monomorphic species. These results suggest that divergent selection along elevational clines has repeatedly favoured polymorphism, and that more uniform selection in altitudinally restricted species may promote colour monomorphism. Our findings are, to our knowledge, the first to link selection acting within species to the presence and absence of colour polymorphism at broader phylogenetic scales. PMID:25876847

Modeling intraspecific adaptation of Abies sachalinensis to local altitude and responses to global warming, based on a 36-year reciprocal transplant experiment.

PubMed

Ishizuka, Wataru; Goto, Susumu

2012-04-01

Intraspecific adaptation in Abies sachalinensis was examined using models based on long-term monitoring data gathered during a reciprocal transplant experiment with eight seed source populations and six transplantation sites along an altitudinal gradient. The consequence of local adaptation was evaluated by testing the home-site advantage for upslope and downslope transplants at five ages. The populations' fitness-linked trait was set as their productivity (tree height × survival rate) at each age. The effects of global warming were evaluated on the basis of the 36-year performance of downslope transplants. Evidence was found for adaptive genetic variation affecting both height and survival from an early age. Increasing the distance between seed source and planting site significantly reduced productivity for both upslope and downslope transplantation, demonstrating the existence of a significant home-site advantage. The decrease in productivity was most distinct for upslope transplantations, indicating strong local adaptation to high altitudes. Global warming is predicted to increase the productivity of high-altitude populations. However, owing to their existing local adaptation, all tested populations exhibited lower productivity under warming than demes that were optimal for the new climate. These negative predictions should be considered when planning the management of locally adapted plant species such as A. sachalinensis.

Xylem formation can be modeled statistically as a function of primary growth and cambium activity.

PubMed

Huang, Jian-Guo; Deslauriers, Annie; Rossi, Sergio

2014-08-01

Primary (budburst, foliage and shoot) growth and secondary (cambium and xylem) growth of plants play a vital role in sequestering atmospheric carbon. However, their potential relationships have never been mathematically quantified and the underlying physiological mechanisms are unclear. We monitored primary and secondary growth in Picea mariana and Abies balsamea on a weekly basis from 2010 to 2013 at four sites over an altitudinal gradient (25-900 m) in the eastern Canadian boreal forest. We determined the timings of onset and termination through the fitted functions and their first derivative. We quantified the potential relationships between primary growth and secondary growth using the mixed-effects model. We found that xylem formation of boreal conifers can be modeled as a function of cambium activity, bud phenology, and shoot and needle growth, as well as species- and site-specific factors. Our model reveals that there may be an optimal mechanism to simultaneously allocate the photosynthetic products and stored nonstructural carbon to growth of different organs at different times in the growing season. This mathematical link can bridge phenological modeling, forest ecosystem productivity and carbon cycle modeling, which will certainly contribute to an improved prediction of ecosystem productivity and carbon equilibrium. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

Ecological status and traditional knowledge of medicinal plants in Kedarnath Wildlife Sanctuary of Garhwal Himalaya, India

PubMed Central

2013-01-01

Background Himalayan forests are the most important source of medicinal plants and with useful species for the local people. Kedarnath Wildlife Sanctuary (KWLS) is situated in the interior part of the Garhwal Himalayan region. The presented study was carried out in Madhmeshwar area of KWLS for the ecological status of medicinal plants and further focused on the ethnomedicinal uses of these plants in the study area. Methods Ecological information about ethnomedicinal plants were collected using random quadrats in a random sampling technique along an altitudinal gradient in the KWLS. Information on medicinal properties of plants encountered in the present study was generated by questionnaire survey and was also compared with relevant literature. Results A total of 152 medicinally important plant species were reported, in which 103 were found herbs, 32 shrubs and 17 were tree species which represented 123 genera of 61 families. A total of 18 plant species fell into the rare, endangered (critically endangered) and vulnerable status categories. Conclusion The present study documented the traditional uses of medicinal plants, their ecological status and importance of these plants in the largest protected area of Garhwal Himalaya. This study can serve as baseline information on medicinal plants and could be helpful to further strengthen the conservation of this important resource. PMID:23281594

Biodiversity promotes primary productivity and growing season lengthening at the landscape scale

PubMed Central

Niklaus, Pascal A.

2017-01-01

Experiments have shown positive biodiversity-ecosystem functioning (BEF) relationships in small plots with model communities established from species pools typically comprising few dozen species. Whether patterns found can be extrapolated to complex, nonexperimental, real-world landscapes that provide ecosystem services to humans remains unclear. Here, we combine species inventories from a large-scale network of 447 1-km2 plots with remotely sensed indices of primary productivity (years 2000–2015). We show that landscape-scale productivity and its temporal stability increase with the diversity of plants and other taxa. Effects of biodiversity indicators on productivity were comparable in size to effects of other important drivers related to climate, topography, and land cover. These effects occurred in plots that integrated different ecosystem types (i.e., metaecosystems) and were consistent over vast environmental and altitudinal gradients. The BEF relations we report are as strong or even exceed the ones found in small-scale experiments, despite different community assembly processes and a species pool comprising nearly 2,000 vascular plant species. Growing season length increased progressively over the observation period, and this shift was accelerated in more diverse plots, suggesting that a large species pool is important for adaption to climate change. Our study further implies that abiotic global-change drivers may mediate ecosystem functioning through biodiversity changes. PMID:28874547

Diversity of Forest Litter-Inhabiting Ants Along Elevations in the Wayanad Region of the Western Ghats

PubMed Central

Sabu, Thomas K.; Vineesh, P. J.; Vinod, K.V.

2008-01-01

Litter ant diversity and abundance in relation to biotic and abiotic factors were analyzed at five primary forest sites lying between 300 to 1650 meter above mean sea level in the Wayanad region of the Western Ghats in Kerala, southern India. Ant abundance and species richness peaked at mid-elevations influenced by the presence of favourable physical conditions and abundance of prey resources. Dominance of ants preferring termites and Collembola as prey at sites rich in their specific prey resources indicate the influence of local prey resource availability in determining ant distribution. Dominant species (Tapinoma sp. and Solenopsis sp.) had wider distributions, being present at all elevations. Physical factors (slope of the terrain, rainfall, moisture, humidity, temperature) and prey resource availability (insect larvae, termites, Collembola) influenced ant species abundance at a regional scale, whereas at local scales, site specific variations in the relationship between abundance of ants and prey-predators and physical factors were recorded. The present study highlights the need to consider site-specific abiotic and biotic factors while examining the distribution patterns of litter ants along altitudinal gradients in other regions of the Western Ghats, which is a recognised hot spot of biodiversity with wide regional variation in vegetation types and faunal distribution patterns.

Diversity and Distribution of Freshwater Amphipod Species in Switzerland (Crustacea: Amphipoda)

PubMed Central

Altermatt, Florian; Alther, Roman; Fišer, Cene; Jokela, Jukka; Konec, Marjeta; Küry, Daniel; Mächler, Elvira; Stucki, Pascal; Westram, Anja Marie

2014-01-01

Amphipods are key organisms in many freshwater systems and contribute substantially to the diversity and functioning of macroinvertebrate communities. Furthermore, they are commonly used as bioindicators and for ecotoxicological tests. For many areas, however, diversity and distribution of amphipods is inadequately known, which limits their use in ecological and ecotoxicological studies and handicaps conservation initiatives. We studied the diversity and distribution of amphipods in Switzerland (Central Europe), covering four major drainage basins, an altitudinal gradient of>2,500 m, and various habitats (rivers, streams, lakes and groundwater). We provide the first provisional checklist and detailed information on the distribution and diversity of all amphipod species from Switzerland. In total, we found 29 amphipod species. This includes 16 native and 13 non-native species, one of the latter (Orchestia cavimana) reported here for the first time for Switzerland. The diversity is compared to neighboring countries. We specifically discuss species of the genus Niphargus, which are often receiving less attention. We also found evidence of an even higher level of hidden diversity, and the potential occurrence of further cryptic species. This diversity reflects the biogeographic past of Switzerland, and suggests that amphipods are ideally suited to address questions on endemism and adaptive radiations, post-glaciation re-colonization and invasion dynamics as well as biodiversity-ecosystem functioning relationships in aquatic systems. PMID:25354099

Enzymatic mechanisms of soil-carbon response to temperature on Mt. Kilimanjaro

NASA Astrophysics Data System (ADS)

Blagodatskaya, Evgenia; Blagodatskiy, Sergey; Kuzyakov, Yakov

2016-04-01

Short-term acceleration of soil organic matter (SOM) decomposition by increasing temperature contradicts the acclimation observed in long-term studies. We used the unique altitudinal gradient (from colline tropical zone to subalpine zone) on Mt. Kilimanjaro to demonstrate the mechanisms of short- and long-term acclimation of extra- and intracellular enzymes that decompose polymers (cellulose, chitin, phytate) and oxidize monomers (14C-glucose). Basing on Michaelis-Menten kinetics we determined the enzymes affinity to substrate (Km) and mineralization potential of heterotrophic microorganisms (Vmax) 1) for three hydrolytic enzymes: β-1,4-glucosidase, N-acetyl- β -D-glucosaminidase and phosphatase by the application of fluorogenically labeled substrates and 2) for mineralization of 14C-labeled glucose by substrate-dependent respiratory response. Here we show that the amount of available substrate is responsible for temperature sensitivity of hydrolysis of polymers in soil, whereas monomers oxidation to CO2 does not depend on substrate amount and is mainly temperature governed. We also found that substrate affinity of enzymes (which is usually decreases with the temperature) differently responded to warming for the process of depolymerisation versus monomers oxidation. We suggest the mechanism to temperature acclimation based on different temperature sensitivity of enzymes kinetics for hydrolysis of polymers and for monomers oxidation

Genetic structure and isolation by altitude in rice landraces of Yunnan, China revealed by nucleotide and microsatellite marker polymorphisms

PubMed Central

A, Xinxiang; Yu, Tengqiong; Ma, Xiaoding; Zhang, Enlai; Wang, Yanjie; Cao, Guilan; Xu, Furong; Dai, Luyuan; Han, Longzhi

2017-01-01

Rice landraces, a genetic reservoir for varietal improvement, are developed by farmers through artificial selection during the long-term domestication process. To efficiently conserve, manage, and use such germplasm resources, an understanding of the genetic structure and differentiation of local rice landraces is required. In this study, we analyzed 188 accessions of rice landraces collected from localities across an altitudinal gradient from 425 to 2, 274 m above sea level in Yunnan Province, China using ten target genes and 48 SSR markers. We detected clear differentiation of the rice landraces into indica and japonica groups and further separation of the accessions in each group into two subgroups according to altitude, including a lower altitude subgroup and higher altitude subgroup. The AMOVA results showed significant genetic differentiation among altitude zones at SSRs and most genes, except Os1977 and STS22. We further determined that differentiation among landrace populations followed a model of isolation by altitude, in which gene flow was higher among populations at similar altitude levels than across different altitude levels. Our findings demonstrated that both adaptation to altitude and altitude-dependent gene flow played key roles in the genetic differentiation of rice landraces in Yunnan, China. PMID:28423046

Genetic structure and isolation by altitude in rice landraces of Yunnan, China revealed by nucleotide and microsatellite marker polymorphisms.

PubMed

Cui, Di; Tang, Cuifeng; Li, Jinmei; A, Xinxiang; Yu, Tengqiong; Ma, Xiaoding; Zhang, Enlai; Wang, Yanjie; Cao, Guilan; Xu, Furong; Dai, Luyuan; Han, Longzhi; Koh, Hee-Jong

2017-01-01

Rice landraces, a genetic reservoir for varietal improvement, are developed by farmers through artificial selection during the long-term domestication process. To efficiently conserve, manage, and use such germplasm resources, an understanding of the genetic structure and differentiation of local rice landraces is required. In this study, we analyzed 188 accessions of rice landraces collected from localities across an altitudinal gradient from 425 to 2, 274 m above sea level in Yunnan Province, China using ten target genes and 48 SSR markers. We detected clear differentiation of the rice landraces into indica and japonica groups and further separation of the accessions in each group into two subgroups according to altitude, including a lower altitude subgroup and higher altitude subgroup. The AMOVA results showed significant genetic differentiation among altitude zones at SSRs and most genes, except Os1977 and STS22. We further determined that differentiation among landrace populations followed a model of isolation by altitude, in which gene flow was higher among populations at similar altitude levels than across different altitude levels. Our findings demonstrated that both adaptation to altitude and altitude-dependent gene flow played key roles in the genetic differentiation of rice landraces in Yunnan, China.

Interaction networks and the use of floral resources by male orchid bees (Hymenoptera: Apidae: Euglossini) in a primary rain forests of the Chocó Region (Colombia).

PubMed

Ospina-Torres, Rodulfo; Montoya-Pfeiffer, Paula María; Parra-H, Alejandro; Solarte, Victor; Tupac Otero, Joel

2015-09-01

Orchid bees are important keystone pollinators from the Neotropics. With the aim to study the relationships between orchid bees and their nectar and aromatic host species, we made systematic samplings of males across two conservation areas in the biogeographic Choc6 Region of Colombia. We used chemical baits to collect 352 male bees during five months. The pollen attached to their bodies was extracted for palynological identification and to estimate interaction networks. The euglossine community consisted of at least 22 species including Eg. maculilabris, Eg. orellana, Eg. championi and Eg. ignita. The male bees were associated with 84 plants but depended on a small group of them (Peperomia spp. and Anthurium spp, as well as species of Solanaceae, Ericaceae and Malpighiaceae) which were widely distributed across the altitudinal gradient, and were available through the year. The resulting interaction networks revealed a typical nested pattern usually found in plant-pollinator interactions, with several rare bee and plant species interaction with a small group of generalist bees and plant species. Albeit, we found variation within networks related to species composition. Such variation may be a consequence of specific differences in plant flowering phenology.

How the timberline formed: altitudinal changes in stand structure and dynamics around the timberline in central Japan

PubMed Central

Takahashi, Koichi; Hirosawa, Tatsuru; Morishima, Ryohei

2012-01-01

Background and Aims Altitudinal timberlines are thought to move upward by global warming, a crucial topic in ecology. Tall tree species (the conifer Abies mariesii and the deciduous broad-leaved Betula ermanii) dominate the sub-alpine zone between 1600 and 2500 m a.s.l., the timberline, on Mount Norikura in central Japan. Dwarf pine Pinus pumila dominates above the timberline to near the summit (3026 m a.s.l.). This study evaluated how the timberline formed on Mount Norikura by examining altitudinal changes in stand structure and dynamics around the timberline. Methods One hundred and twenty-five plots of 10 m × 10 m were established around the timberline (2350–2600 m a.s.l.). Trunk diameter growth rate during 6 years was examined for A. mariesii, B. ermanii and P. pumila. Mortality during this period and mechanical damage scars on the trunks and branches due to strong wind and snow were examined for A. mariesii only. Key Results The density, maximum trunk height and diameter of A. mariesii in plots decreased with altitude. The maximum trunk height of B. ermanii decreased with altitude, but density and maximum trunk diameter did not decrease. In contrast, the density of P. pumila abruptly increased from around the timberline. A strong negative correlation was found between the densities of P. pumila and tall tree species, indicating their interspecific competition. Trunk diameter growth rates of A. mariesii and B. ermanii did not decrease with altitude, suggesting that these two tall tree species can grow at the timberline. The ratio of trees with mechanical damage scars increased with altitude for A. mariesii, a tendency more conspicuous for larger trees. The mortality of larger A. mariesii was also greater at higher altitude. Tall tree species may not increase their trunk height and survive around the timberline because of mechanical damage. Conclusions This study suggests that the altitudinal location of the timberline is mainly affected by mechanical damage due to strong wind and snow rather than by growth limitation due to low temperature. Therefore, the timberline would not move upward even under global warming if these growth and mortality characteristics do not change for a long time. PMID:22451598

Global patterns of protection of elevational gradients in mountain ranges.

PubMed

Elsen, Paul R; Monahan, William B; Merenlender, Adina M

2018-05-21

Protected areas (PAs) that span elevational gradients enhance protection for taxonomic and phylogenetic diversity and facilitate species range shifts under climate change. We quantified the global protection of elevational gradients by analyzing the elevational distributions of 44,155 PAs in 1,010 mountain ranges using the highest resolution digital elevation models available. We show that, on average, mountain ranges in Africa and Asia have the lowest elevational protection, ranges in Europe and South America have intermediate elevational protection, and ranges in North America and Oceania have the highest elevational protection. We use the Convention on Biological Diversity's Aichi Target 11 to assess the proportion of elevational gradients meeting the 17% suggested minimum target and examine how different protection categories contribute to elevational protection. When considering only strict PAs [International Union for Conservation of Nature (IUCN) categories I-IV, n = 24,706], nearly 40% of ranges do not contain any PAs, roughly half fail to meet the 17% target at any elevation, and ∼75% fail to meet the target throughout ≥50% of the elevational gradient. Observed elevational protection is well below optimal, and frequently below a null model of elevational protection. Including less stringent PAs (IUCN categories V-VI and nondesignated PAs, n = 19,449) significantly enhances elevational protection for most continents, but several highly biodiverse ranges require new or expanded PAs to increase elevational protection. Ensuring conservation outcomes for PAs with lower IUCN designations as well as strategically placing PAs to better represent and connect elevational gradients will enhance ecological representation and facilitate species range shifts under climate change. Copyright © 2018 the Author(s). Published by PNAS.

Climate change and apple farming in Indian Himalayas: a study of local perceptions and responses.

PubMed

Basannagari, Basavaraj; Kala, Chandra Prakash

2013-01-01

Apple farming is an important activity and profession of farmer communities in the Himalayan states of India. At present, the traditional apple farming is under stress due to changes in climate. The present study was undertaken in an Indian Himalayan state, Himachal Pradesh, with the major aim of studying perceptions of farmers on the effects of climate change on apple farming along the altitudinal gradient. Through questionnaire survey, the perceptions of farmers were recorded at low hills (<2500 m), mid-hills (2500-3000 m), and upper hills (>3000 m). At all elevation range the majority of farmers reported that there was increase in atmospheric temperature, and hence at low hills 72% farmers believed that this increase in temperature was responsible for decline in fruit size and so that the quality. Thirty five percent farmers at high hills and 30% at mid hills perceived frost as a major cause for damaging apple farming whereas at low hills 24% farmers perceived hailstorm as the major deterrent for apple farming. The majority of farmers, along the altitude (92% at high hills, 79% at mid hills and 83% at low hills), reported decrease in snowfall. The majority of farmers at low altitude and mid altitude reported decline in apple farming whereas 71% farmers at high hill areas refused decline in apple farming. About 73-83% farmers admitted delay in apple's harvesting period. At mid hills apple scab and at low hills pest attack on apple crops are considered as the indicators of climate change. The change in land use practices was attributed to climate change and in many areas the land under apple farming was replaced for production of coarse grains, seasonal vegetables and other horticulture species. Scientific investigation claiming changes in Indian Himalayan climate corroborates perceptions of farmers, as examined during the present study.

Canopy structure of tropical and sub-tropical rain forests in relation to conifer dominance analysed with a portable LIDAR system

PubMed Central

Aiba, Shin-ichiro; Akutsu, Kosuke; Onoda, Yusuke

2013-01-01

Background and Aims Globally, conifer dominance is restricted to nutient-poor habitats in colder, drier or waterlogged environments, probably due to competition with angiosperms. Analysis of canopy structure is important for understanding the mechanism of plant coexistence in relation to competition for light. Most conifers are shade intolerant, and often have narrow, deep, conical crowns. In this study it is predicted that conifer-admixed forests have less distinct upper canopies and more undulating canopy surfaces than angiosperm-dominated forests. Methods By using a ground-based, portable light detection and ranging (LIDAR) system, canopy structure was quantified for old-growth evergreen rainforests with varying dominance of conifers along altitudinal gradients (200–3100 m a.s.l.) on tropical and sub-tropical mountains (Mount Kinabalu, Malaysian Borneo and Yakushima Island, Japan) that have different conifer floras. Key Results Conifers dominated at higher elevations on both mountains (Podocarpaceae and Araucariaceae on Kinabalu and Cupressaceae and Pinaceae on Yakushima), but conifer dominance also varied with soil/substrate conditions on Kinabalu. Conifer dominance was associated with the existence of large-diameter conifers. Forests with higher conifer dominance showed a canopy height profile (CHP) more skewed towards the understorey on both Kinabalu and Yakushima. In contrast, angiosperm-dominated forests had a CHP skewed towards upper canopy, except for lowland dipterocarp forests and a sub-alpine scrub dominated by small-leaved Leptospermum recurvum (Myrtaceae) on Kinabalu. Forests with a less dense upper canopy had more undulating outer canopy surfaces. Mixed conifer–angiosperm forests on Yakushima and dipterocarp forests on Kinabalu showed similar canopy structures. Conclusions The results generally supported the prediction, suggesting that lower growth of angiosperm trees (except L. recurvum on Kinabalu) in cold and nutrient-poor environments results in a sparser upper canopy, which allows shade-intolerant conifers to co-occur with angiosperm trees either as emergents or as codominants in the open canopy. PMID:24197751

Canopy structure of tropical and sub-tropical rain forests in relation to conifer dominance analysed with a portable LIDAR system.

PubMed

Aiba, Shin-ichiro; Akutsu, Kosuke; Onoda, Yusuke

2013-12-01

Globally, conifer dominance is restricted to nutient-poor habitats in colder, drier or waterlogged environments, probably due to competition with angiosperms. Analysis of canopy structure is important for understanding the mechanism of plant coexistence in relation to competition for light. Most conifers are shade intolerant, and often have narrow, deep, conical crowns. In this study it is predicted that conifer-admixed forests have less distinct upper canopies and more undulating canopy surfaces than angiosperm-dominated forests. By using a ground-based, portable light detection and ranging (LIDAR) system, canopy structure was quantified for old-growth evergreen rainforests with varying dominance of conifers along altitudinal gradients (200-3100 m a.s.l.) on tropical and sub-tropical mountains (Mount Kinabalu, Malaysian Borneo and Yakushima Island, Japan) that have different conifer floras. Conifers dominated at higher elevations on both mountains (Podocarpaceae and Araucariaceae on Kinabalu and Cupressaceae and Pinaceae on Yakushima), but conifer dominance also varied with soil/substrate conditions on Kinabalu. Conifer dominance was associated with the existence of large-diameter conifers. Forests with higher conifer dominance showed a canopy height profile (CHP) more skewed towards the understorey on both Kinabalu and Yakushima. In contrast, angiosperm-dominated forests had a CHP skewed towards upper canopy, except for lowland dipterocarp forests and a sub-alpine scrub dominated by small-leaved Leptospermum recurvum (Myrtaceae) on Kinabalu. Forests with a less dense upper canopy had more undulating outer canopy surfaces. Mixed conifer-angiosperm forests on Yakushima and dipterocarp forests on Kinabalu showed similar canopy structures. The results generally supported the prediction, suggesting that lower growth of angiosperm trees (except L. recurvum on Kinabalu) in cold and nutrient-poor environments results in a sparser upper canopy, which allows shade-intolerant conifers to co-occur with angiosperm trees either as emergents or as codominants in the open canopy.

Treeline advances along the Urals mountain range - driven by improved winter conditions?

PubMed

Hagedorn, Frank; Shiyatov, Stepan G; Mazepa, Valeriy S; Devi, Nadezhda M; Grigor'ev, Andrey A; Bartysh, Alexandr A; Fomin, Valeriy V; Kapralov, Denis S; Terent'ev, Maxim; Bugman, Harald; Rigling, Andreas; Moiseev, Pavel A

2014-11-01

High-altitude treelines are temperature-limited vegetation boundaries, but little quantitative evidence exists about the impact of climate change on treelines in untouched areas of Russia. Here, we estimated how forest-tundra ecotones have changed during the last century along the Ural mountains. In the South, North, Sub-Polar, and Polar Urals, we compared 450 historical and recent photographs and determined the ages of 11,100 trees along 16 altitudinal gradients. In these four regions, boundaries of open and closed forests (crown covers above 20% and 40%) expanded upwards by 4 to 8 m in altitude per decade. Results strongly suggest that snow was an important driver for these forest advances: (i) Winter precipitation has increased substantially throughout the Urals (~7 mm decade(-1) ), which corresponds to almost a doubling in the Polar Urals, while summer temperatures have only changed slightly (~0.05°C decade(-1) ). (ii) There was a positive correlation between canopy cover, snow height and soil temperatures, suggesting that an increasing canopy cover promotes snow accumulation and, hence, a more favorable microclimate. (iii) Tree age analysis showed that forest expansion mainly began around the year 1900 on concave wind-sheltered slopes with thick snow covers, while it started in the 1950s and 1970s on slopes with shallower snow covers. (iv) During the 20th century, dominant growth forms of trees have changed from multistemmed trees, resulting from harsh winter conditions, to single-stemmed trees. While 87%, 31%, and 93% of stems appearing before 1950 were from multistemmed trees in the South, North and Polar Urals, more than 95% of the younger trees had a single stem. Currently, there is a high density of seedlings and saplings in the forest-tundra ecotone, indicating that forest expansion is ongoing and that alpine tundra vegetation will disappear from most mountains of the South and North Urals where treeline is already close to the highest peaks. © 2014 John Wiley & Sons Ltd.

TEMPERATURE-GRADIENT INCUBATOR FOR DETERMINING THE TEMPERATURE RANGE OF GROWTH OF MICROORGANISMS

PubMed Central

Elliott, R. Paul

1963-01-01

Elliott, R. Paul (U.S. Department of Agriculture, Albany, Calif.). Temperature-gradient incubator for determining the temperature range of growth of microorganisms. J. Bacteriol. 85:889–894. 1963.—The temperature-gradient incubator consists of an aluminum bar with troughs for media, with controlled temperatures at each end, and with insulation to prevent heat transfer. The resulting linear temperature gradient provides a means for determining minimal or maximal growth temperatures of microorganisms in any desired range and at any desired gradient. The operation of the incubator is unaffected by line-voltage variations or by ambient temperature. Media do not dehydrate seriously even during prolonged periods of operation. The incubator can be used to determine water activity of media by an adjustment to permit partial freezing. Either thermocouples or thermistors may be used to measure temperatures. Images PMID:14044959

Rhizospheric Bacterial Community of Endemic Rhododendron arboreum Sm. Ssp. delavayi along Eastern Himalayan Slope in Tawang

PubMed Central

Debnath, Rajal; Yadav, Archana; Gupta, Vijai K.; Singh, Bhim P.; Handique, Pratap J.; Saikia, Ratul

2016-01-01

Information on rhizosphere microbiome of endemic plants from high mountain ecosystems against those of cultivated plantations is inadequate. Comparative bacterial profiles of endemic medicinal plant Rhododendron arboreum Sm. subsp. delavayi rhizosphere pertaining to four altitudinal zonation Pankang Thang (PTSO), Nagula, Y-junction and Bum La (Indo-China border; in triplicates each) along cold adapted Eastern slope of Himalayan Tawang region, India is described here. Significant differences in DGGE profile between below ground bulk vs. rhizospheric community profile associated with the plant was identified. Tagged 16S amplicon sequencing from PTSO (3912 m) to Bum La (4509 m), revealed that soil pH, total nitrogen (TN), organic matter (OM) significantly influenced the underlying bacterial community structure at different altitudes. The relative abundance of Acidobacteria was inversely related to pH, as opposed to TN which was positively correlated to Acidobacteria and Proteobacteria abundance. TN was also the significant predictor for less abundant taxonomic groups Chloroflexi, Gemmatimonadetes, and Nitrospirae. Bum La soil harbored less bacterial diversity compared to other sites at lower altitudes. The most abundant phyla at 3% genetic difference were Acidobacteria, Actinobacteria, and Proteobacteria amongst others. Analysis of similarity indicated greater similarity within lower altitudinal than higher altitudinal group (ANOSIM, R = 0.287, p = 0.02). Constraining the ordination with the edaphic factor explained 83.13% of variation. Unique phylotypes of Bradyrhizobium and uncultured Rhizobiales were found in significant proportions at the four regions. With over 1% relative abundance Actinobacteria (42.6%), Acidobacteria (24.02%), Proteobacteria (16.00%), AD3 (9.23%), WPS-2 (5.1%), and Chloroflexi (1.48%) dominated the core microbiome. PMID:27642287

COMPUTERIZED EXPERT SYSTEM FOR EVALUATION OF AUTOMATED VISUAL FIELDS FROM THE ISCHEMIC OPTIC NEUROPATHY DECOMPRESSION TRIAL: METHODS, BASELINE FIELDS, AND SIX-MONTH LONGITUDINAL FOLLOW-UP

PubMed Central

Feldon, Steven E

2004-01-01

ABSTRACT Purpose To validate a computerized expert system evaluating visual fields in a prospective clinical trial, the Ischemic Optic Neuropathy Decompression Trial (IONDT). To identify the pattern and within-pattern severity of field defects for study eyes at baseline and 6-month follow-up. Design Humphrey visual field (HVF) change was used as the outcome measure for a prospective, randomized, multi-center trial to test the null hypothesis that optic nerve sheath decompression was ineffective in treating nonarteritic anterior ischemic optic neuropathy and to ascertain the natural history of the disease. Methods An expert panel established criteria for the type and severity of visual field defects. Using these criteria, a rule-based computerized expert system interpreted HVF from baseline and 6-month visits for patients randomized to surgery or careful follow-up and for patients who were not randomized. Results A computerized expert system was devised and validated. The system was then used to analyze HVFs. The pattern of defects found at baseline for patients randomized to surgery did not differ from that of patients randomized to careful follow-up. The most common pattern of defect was a superior and inferior arcuate with central scotoma for randomized eyes (19.2%) and a superior and inferior arcuate for nonrandomized eyes (30.6%). Field patterns at 6 months and baseline were not different. For randomized study eyes, the superior altitudinal defects improved (P = .03), as did the inferior altitudinal defects (P = .01). For nonrandomized study eyes, only the inferior altitudinal defects improved (P = .02). No treatment effect was noted. Conclusions A novel rule-based expert system successfully interpreted visual field defects at baseline of eyes enrolled in the IONDT. PMID:15747764

Plant distribution-altitude and landform relationships in karstic sinkholes of Mediterranean region of Turkey.

PubMed

Ozkan, Kürsad; Gulsoy, Serkan; Mert, Ahmet; Ozturk, Munir; Muys, Bart

2010-01-01

The purpose of this study was to investigate the relationships between the plant distribution and the altitude-shape-size characteristics of sinkholes, and the landform characteristics inside sinkholes in the Mediterranean region of Turkey. Block kriging, Factor analysis, Cluster Analysis and Detrended Correspondence Analysis were performed. The sinkhole type and altitudinal zone were found to be the significant factors affecting the plant distribution. However, the sinkhole type was more important than the altitudinal zone. Hence, the sinkholes were first subdivided into groups according to types and then the groups were divided into subgroups according to the altitudinal zones. Consequently, 4 groups were defined; A-type sinkholes [1400-1550 m (A1), 1550-1700 m (A2)] and B-type sinkholes [1400-1550 (B1), 1550-1700 m (B2)]. The B-type was wider vertically and shorter horizontally than A-type sinkholes. Significant differences were found between the plant distribution and slope position inside the sinkholes. Plant distribution in the lower slopes was different from that in the flats and ridges in the B1 sub-type of B-type. Plant distribution in B2 subtype was different among the slope positions (ridge, middle slope, lower slope, and flat). Although distribution of plants is different in different parts (ridges, upper slope, middle slope, lower slope and basal flats) of A sinkhole, the differences between the parts of intermediate slope position are not significant. A high plant variability along short distances in the sinkholes was observed in the study area. That is why the site of sinkholes have a big potential for the distribution of many species. Hence, the area must be separated as strictly protected zone.

The regular nocturnal course of temperature in the midlatitude mesopause region according to hydroxyl airglow measurements

NASA Astrophysics Data System (ADS)

Perminov, V. I.; Pertsev, N. N.

2016-09-01

Using ground-based spectral measurements in the near-infrared range at the Zvenigorod scientific station of the Institute of Atmospheric Physics (56° N, 37° E) for 2000-2013, we obtained average nighttime changes in rotational and vibrational temperatures of hydroxyl with its emission layer localized at mesopause heights. The rotational temperature reflects the kinetic temperature of the emission layer of the atmosphere. The analysis made it possible to determine the characteristics of the first three harmonics of diurnal temperature dynamics in the mesopause region both with and without altitudinal oscillations of the OH emission layer. In both cases, the second and third harmonics are statistically significant: their amplitudes are ˜1 K and the phases of their first maxima are near 0300 and 0130 local solar time.

Altitude-dependent Drift of a Chemical Release Cloud at Middle Latitudes

NASA Astrophysics Data System (ADS)

Pedersen, T.; Holmes, J. M.; Sutton, E. K.

2017-12-01

A chemical release experiment conducted at the White Sands Missile Range in February 2015 consisted of firing of three identical canisters at different altitudes along a near-vertical trajectory, creating a large structured cloud after diffusion and expansion of the three initial dispersals. Dedicated optical observations from near the launch site and a remote site allow determination of the position and motion of the extended optical cloud as a function of time, while photographs captured and posted by members of the general public provide additional look angles to constrain the cloud shape in more detail. We compare the observed drift and evolution of the cloud with empirical and theoretical models of the neutral winds to examine the altitudinal shear in the neutral winds and their effects on the motion and shape of the extended optical cloud.

Low altitude, one centimeter, space debris search at Lincoln Laboratory's (M.I.T.) experimental test system

NASA Technical Reports Server (NTRS)

Taff, L. G.; Beatty, D. E.; Yakutis, A. J.; Randall, P. M. S.

1985-01-01

The majority of work performed by the Lincoln Laboratory's Space Surveillance Group, at the request of NASA, to define the near-earth population of man-made debris is summarized. Electrooptical devices, each with a 1.2 deg FOV, were employed at the GEODSS facility in New Mexico. Details of the equipment calibration and alignment procedures are discussed, together with implementation of a synchronized time code for computer controlled videotaping of the imagery. Parallax and angular speed data served as bases for distinguishing between man-made debris and meteoroids. The best visibility was obtained in dawn and dusk twilight conditions at elevation ranges of 300-2000 km. Tables are provided of altitudinal density distribution of debris. It is noted that the program also yielded an extensive data base on meteoroid rates.

End of Project Report [Upgrading measurement capabilities for hydrocarbons, halocarbons and alkyl nitrates

NASA Technical Reports Server (NTRS)

Blake, Donald R.

1999-01-01

This paper presents the End of Project Report from the P3-B Christmas Island local flights. Altitudinal variations in mixing ratios of several marine emitted gases, including DMS (dimethyl sulfide) are illustrated. This paper is presented in viewgraph form.

Electricity in the Atmosphere.

ERIC Educational Resources Information Center

Sampath, S.; Kumar, V. Sasi

1991-01-01

The theory of the atmospheric electric circuit and a discussion of the fair-weather electrical are presented. The ion concentration, mobility, conductivity, and electric field altitudinal profiles are explained. An outline of the electrical processes inside thunderstorms along with a description of the lightning strike are included. (Author)

Vegetation Response to Upper Pliocene Glacial/Interglacial Cyclicity in the Central Mediterranean

NASA Astrophysics Data System (ADS)

Combourieu-Nebout, Nathalie

1993-09-01

New detailed pollen analysis of the lower part of the Upper Pliocene Semaforo section (Crotone, Italy) documents cyclic behavior of vegetation at the beginning of the Northern Hemisphere glaciations. The competition between four vegetation units (subtropical humid forest, deciduous temperate forest, altitudinal coniferous forest, and open xeric assemblage) probably reflects modifications of vegetation belts at this montane site. Several increases in herbaceous open vegetation regularly alternate with subtropical humid forest, which expresses rapid climatic oscillations. The complete temporal succession—deciduous forest (rich in Quercus), followed by subtropical humid forest (Taxodiaceae and Cathaya), then altitudinal coniferous forest ( Tsuga, Cedrus, Abies, and Picea), and finally herbaceous open vegetation (Graminae, Compositae, and Artemisia )—displays the climatic evolution from warm and humid interglaciation to cold and dry glaciation. It also suggests an independent variation of temperature and humidity, the two main climatic parameters. The vegetation history of southern Calabria recorded in the Semaforo section have been correlated with the ∂ 18O signal established in the Atlantic Ocean.

Lilies at the limit: Variation in plant-pollinator interactions across an elevational range.

PubMed

Theobald, Elli J; Gabrielyan, Hrach; HilleRisLambers, Janneke

2016-02-01

Many studies assume climatic factors are paramount in determining species' distributions, however, biotic interactions may also play a role. For example, pollinators may limit species' ranges if floral abundance or floral attractiveness is reduced at range margins, thus causing lower pollinator visitation and reduced reproductive output. To test if pollinators influence the altitudinal distribution of Erythronium montanum (Liliaceae) at Mount Rainier National Park, we asked whether (1) seed production in this species relies on pollinators, (2) seed production and pollen limitation is greatest at range limits, and (3) pollinator visitation rates (either overall or by individual taxonomic groups) reflect patterns of seed production and pollen limitation. From this three-year study, we established that this plant does rely on pollinators for fruit set and we found that pollen limitation trended toward being higher at the upper range limit in some years, but not consistently year to year. Insect visitation rates did not mirror spatial patterns of pollen limitation, but annually variable pollinator composition suggested differential importance of some pollinator taxonomic groups (specifically, bumblebees may be better pollinators than syrphid flies). Overall, these results suggest that while pollinators are critical for the reproductive success of this high mountain wildflower, plant-pollinator interactions do not obviously drive the distribution of this species. Nonetheless, high spatio-temporal variability in range-wide plant-pollinator dynamics may complicate responses to climate change. © 2016 Botanical Society of America.

Convection driven generation of long-range material gradients

PubMed Central

Du, Yanan; Hancock, Matthew J.; He, Jiankang; Villa-Uribe, Jose; Wang, Ben; Cropek, Donald M.; Khademhosseini, Ali

2009-01-01

Natural materials exhibit anisotropy with variations in soluble factors, cell distribution, and matrix properties. The ability to recreate the heterogeneity of the natural materials is a major challenge for investigating cell-material interactions and for developing biomimetic materials. Here we present a generic fluidic approach using convection and alternating flow to rapidly generate multi-centimeter gradients of biomolecules, polymers, beads and cells and cross-gradients of two species in a microchannel. Accompanying theoretical estimates and simulations of gradient growth provide design criteria over a range of material properties. A poly(ethyleneglycol) hydrogel gradient, a porous collagen gradient and a composite material with a hyaluronic acid/gelatin cross-gradient were generated with continuous variations in material properties and in their ability to regulate cellular response. This simple yet generic fluidic platform should prove useful for creating anisotropic biomimetic materials and high-throughput platforms for investigating cell-microenvironment interaction. PMID:20035990

Response to climate change of montane herbaceous plants in the genus Rhodiola predicted by ecological niche modelling.

PubMed

You, Jianling; Qin, Xiaoping; Ranjitkar, Sailesh; Lougheed, Stephen C; Wang, Mingcheng; Zhou, Wen; Ouyang, Dongxin; Zhou, Yin; Xu, Jianchu; Zhang, Wenju; Wang, Yuguo; Yang, Ji; Song, Zhiping

2018-04-12

Climate change profoundly influences species distributions. These effects are evident in poleward latitudinal range shifts for many taxa, and upward altitudinal range shifts for alpine species, that resulted from increased annual global temperatures since the Last Glacial Maximum (LGM, ca. 22,000 BP). For the latter, the ultimate consequence of upward shifts may be extinction as species in the highest alpine ecosystems can migrate no further, a phenomenon often characterized as "nowhere to go". To predict responses to climate change of the alpine plants on the Qinghai-Tibetan Plateau (QTP), we used ecological niche modelling (ENM) to estimate the range shifts of 14 Rhodiola species, beginning with the Last Interglacial (ca. 120,000-140,000 BP) through to 2050. Distributions of Rhodiola species appear to be shaped by temperature-related variables. The southeastern QTP, and especially the Hengduan Mountains, were the origin and center of distribution for Rhodiola, and also served as refugia during the LGM. Under future climate scenario in 2050, Rhodiola species might have to migrate upward and northward, but many species would expand their ranges contra the prediction of the "nowhere to go" hypothesis, caused by the appearance of additional potential habitat concomitant with the reduction of permafrost with climate warming.

Sampling High-Altitude and Stratified Mating Flights of Red Imported Fire Ant

USDA-ARS?s Scientific Manuscript database

With the exception of an airplane equipped with nets, no method has been developed that successfully samples red imported fire ant, Solenopsis invicta Buren, sexuals in mating/dispersal flights throughout their potential altitudinal trajectories. We developed and tested a method for sampling queens ...

Human fascioliasis in South Africa.

PubMed

Black, J; Ntusi, N; Stead, P; Mayosi, B; Mendelson, M

2013-07-29

Human fascioliasis has the widest latitudinal, longitudinal and altitudinal distribution of any vector-borne disease, yet only 3 cases have been reported from South Africa, the last in 1964. We report 2 cases from the same geographic area associated with local consumption of watercress, suggesting an endemic focus. 

INFILTRATION ON MOUNTAIN SLOPES: A COMPARISON OF THREE ENVIRONMENTS. (R825157)

EPA Science Inventory

Water is well established as a major driver of the geomorphic change that eventually reduces mountains to lower relief landscapes. Nonetheless, within the altitudinal limits of continuous vegetation in humid climates, water is also an essential factor in slope stability. In th...

Soils evolution and treeline fluctuations under late Holocene climatic changes: an integrated approach from Valle d'Aosta (Western European Alps, Italy)

NASA Astrophysics Data System (ADS)

Masseroli, Anna; Leonelli, Giovanni; Verrecchia, Eric P.; Sebag, David; Pozzi, Emanuele D.; Pelfini, Manuela; Maggi, Valter; Trombino, Luca

2017-04-01

The treeline ecotone, defined as the transition belt in mountain vegetation between the closed forest (timberline) and the alpine grasslands, is one of the most distinctive features of mountain environments and it is widely considered as a climatic boundary. Treeline altitudinal fluctuations may be considered to assess past and ongoing climatic and environmental changes. Although the ecological dynamics of the alpine treeline ecotone is mainly influenced by climate, especially by soil temperature, climatic parameters are not the only factors that influence the treeline position. In fact, the treeline altitude may be locally influenced by environmental factors, geomorphological processes, soil development, and human activities. This study aims at the reconstruction of late Holocene soil evolution and environmental changes at the treeline on the SW slope of the Becca di Viou Mountain in Valle d'Aosta (Western Italian Alps). First, we performed a detailed reconstruction of the treeline altitudinal dynamics. In addition, field (including air and soil temperatures) and laboratory (of both mineral and organic compounds) characterizations have been performed along two transects of seven soil profiles developing at an altitude ranging from 2100 m a.s.l. (closed forest) to 2400 m a.s.l. (treeline ecotone), in order to understand the relationships between colonization by trees and soil development under the ongoing climate change. The upward shift of the treeline was assessed analyzing tree age distribution along the slope by means of a tree-ring based approach. The reconstruction of the treeline altitudinal dynamics (based on years at which the trees reached 2 m in height) at the study site reveals an upward shift of 115 m over the period 1901-2000, reaching the altitude of 2515 m a.s.l. in 2008. The recent treeline shift and the acceleration of tree colonization rates in the alpine belt can be mainly attributed to a climatic input, and particularly to an increasing temperature. The investigated soils show a decreasing development with increasing altitude. Indeed, in the forest area (about 2100 m a.s.l.) soils are well developed (i.e. Podzol), but at higher altitude, they are less developed (i.e. Ranker). In the treeline ecotone, possible traces of Paleosols are also observed. However, future treeline upward shifts in the study area might be severely limited by the geomorphic processes: even if temperature will continue to increase, at higher altitudes, the treeline will meet harsher geomorphic environments characterized by high-energy gravity processes and rock faces that impede soil evolution and tree colonization. The integrated analysis of geopedological, dendrochronological and climate data will provide high resolution information about the responses of high-altitude biological and abiological systems through the Holocene and to the ongoing climate change.

Factors Determining Forest Diversity and Biomass on a Tropical Volcano, Mt. Rinjani, Lombok, Indonesia

PubMed Central

Dossa, Gbadamassi G. O.; Paudel, Ekananda; Fujinuma, Junichi; Yu, Haiying; Chutipong, Wanlop; Zhang, Yuan; Paz, Sherryl; Harrison, Rhett D.

2013-01-01

Tropical volcanoes are an important but understudied ecosystem, and the relationships between plant species diversity and compositional change and elevation may differ from mountains created by uplift, because of their younger and more homogeneous soils. We sampled vegetation over an altitudinal gradient on Mt. Rinjani, Lombok, Indonesia. We modeled alpha- (plot) and beta- (among plot) diversity (Fisher's alpha), compositional change, and biomass against elevation and selected covariates. We also examined community phylogenetic structure across the elevational gradient. We recorded 902 trees and shrubs among 92 species, and 67 species of ground-cover plants. For understorey, subcanopy and canopy plants, an increase in elevation was associated with a decline in alpha-diversity, whereas data for ground-cover plants suggested a hump-shaped pattern. Elevation was consistently the most important factor in determining alpha-diversity for all components. The alpha-diversity of ground-cover vegetation was also negatively correlated with leaf area index, which suggests low light conditions in the understorey may limit diversity at lower elevations. Beta-diversity increased with elevation for ground-cover plants and declined at higher elevations for other components of the vegetation. However, statistical power was low and we could not resolve the relative importance to beta-diversity of different factors. Multivariate GLMs of variation in community composition among plots explained 67.05%, 27.63%, 18.24%, and 19.80% of the variation (deviance) for ground-cover, understorey, subcanopy and canopy plants, respectively, and demonstrated that elevation was a consistently important factor in determining community composition. Above-ground biomass showed no significant pattern with elevation and was also not significantly associated with alpha-diversity. At lower elevations communities had a random phylogenetic structure, but from 1600 m communities were phylogenetically clustered. This suggests a greater role of environmental filtering at higher elevations, and thus provides a possible explanation for the observed decline in diversity with elevation. PMID:23935842

Glacial influence and stream macroinvertebrate biodiversity under climate change: Lessons from the Southern Alps.

PubMed

Lencioni, Valeria

2018-05-01

The aim of this work was to highlight the main ecological predictors driving invertebrate distribution in eight glacier-fed streams in the Southern Alps. Thirty-five sites belonging to four stream types were sampled monthly during the ablation season of one, two or three years between 1996 and 2014. Taxa from glacial (kryal and glacio-rhithral) and non-glacial (kreno-rhithral and lake outlet) sites were separated by canonical correspondence analysis (CCA) along a glacial influence gradient and a hydrological-altitudinal gradient. High glacial influence was associated mainly with low maximum water temperature (Tmax), high Glacial Index (calculated as a function of glacier area and distance from the glacier), and the abundance of Diamesa species (D. steinboecki, D. goetghebueri, D. zernyi, and D. latitarsis). Change-point analysis and Threshold Indicator Taxa Analysis confirmed the CCA results in identifying these Diamesa species as the taxa with the strongest preference for high percent glacier cover in the catchment (change point~30%) and low Tmax (change point~6°C). Temporal changes in community structure were highlighted in seven sites fed by glaciers under different retreat rates. Where the rate was faster and the remaining glacier smaller (≪1km 2 ), the most cold-stenothermal kryal inhabitant, D. steinboecki, almost disappeared or survived only as brachypterous populations, whereas other Diamesinae (Pseudokiefferiella parva), Orthocladiinae (e.g. Eukiefferiella, Orthocladius), Limoniidae, Baetidae, Nemouridae, and non-insect taxa (e.g. Oligochaeta, Hydracarina) became more abundant. Upstream migration was observed in Diamesa spp. which conquered new stream reaches left free by the retreating glacier, and euriecious taxa which colonized reaches with ameliorated environmental conditions, no longer the exclusive habitat of Diamesa spp. Co-occurrence of stochastic and deterministic assembly processes seem to drive spatio-temporal changes in these invertebrate communities. Long-term ecological studies on the adaptive biology of kryal species will be useful to predict the fate of Alpine biodiversity. Copyright © 2017 Elsevier B.V. All rights reserved.

Controls on soil solution nitrogen along an altitudinal gradient in the Scottish uplands.

PubMed

Jackson-Blake, L; Helliwell, R C; Britton, A J; Gibbs, S; Coull, M C; Dawson, L

2012-08-01

Nitrogen (N) deposition continues to threaten upland ecosystems, contributing to acidification, eutrophication and biodiversity loss. We present results from a monitoring study aimed at investigating the fate of this deposited N within a pristine catchment in the Cairngorm Mountains (Scotland). Six sites were established along an elevation gradient (486-908 m) spanning the key habitats of temperate maritime uplands. Bulk deposition chemistry, soil carbon content, soil solution chemistry, soil temperature and soil moisture content were monitored over a 5 year period. Results were used to assess spatial variability in soil solution N and to investigate the factors and processes driving this variability. Highest soil solution inorganic N concentrations were found in the alpine soils at the top of the hillslope. Soil carbon stock, soil solution dissolved organic carbon (DOC) and factors representing site hydrology were the best predictors of NO(3)(-) concentration, with highest concentrations at low productivity sites with low DOC and freely-draining soils. These factors act as proxies for changing net biological uptake and soil/water contact time, and therefore support the hypothesis that spatial variations in soil solution NO(3)(-) are controlled by habitat N retention capacity. Soil percent carbon was a better predictor of soil solution inorganic N concentration than mass of soil carbon. NH(4)(+) was less affected by soil hydrology than NO(3)(-) and showed the effects of net mineralization inputs, particularly at Racomitrium heath and peaty sites. Soil solution dissolved organic N concentration was strongly related to both DOC and temperature, with a stronger temperature effect at more productive sites. Due to the spatial heterogeneity in N leaching potential, a fine-scale approach to assessing surface water vulnerability to N leaching is recommended over the broad scale, critical loads approach currently in use, particularly for sensitive areas. Copyright © 2012 Elsevier B.V. All rights reserved.

Analysis of selected fungi variation and its dependence on season and mountain range in southern Poland-key factors in drawing up trial guidelines for aeromycological monitoring.

PubMed

Pusz, Wojciech; Weber, Ryszard; Dancewicz, Andrzej; Kita, Włodzimierz

2017-09-27

The aim of the study was to identify fungal spores, in particular plant pathogenic fungi, occurring in the air in selected mountain ranges. The results revealed not only the array of fungal species migrating with air currents from the Czech Republic and Slovakia but also how the season of the year affects the distribution of spores. Such studies may lay a foundation for future aeromycological monitoring, in accordance with the requirements for integrated plant protection. Aeromycological research was carried out between 2013 and 2016 at 3-month intervals in mountainous areas along the southern borders of Poland: the Bieszczady, the Pieniny, the Giant Mountains (Karkonosze) and the Babia Góra Massif. The research relied on impact method employing Air Ideal 3P sampler, which, by drawing in atmospheric air, also collects fungal spores. Regardless of altitudinal zonation, the changing weather conditions appeared to be the main reason for the variations in the number of the fungal spores under study in those years.

Performance of the herb Verbascum thapsus along environmental gradients in its native and non-native ranges

Treesearch

Tim Seipel; Jake M. Alexander; Curtis C. Daehler; Lisa J. Rew; Peter J. Edwards; Pervaiz A. Dar; Keith McDougall; Bridgett Naylor; Catherine Parks; Fredric W. Pollnac; Zafar A. Reshi; Mel Schroder; Christoph Kueffer; Peter Pearman

2014-01-01

Aim We evaluated whether the performance of individuals and populations of the invasive plant Verbascum thapsus differs between its native and non-native ranges, across climate gradients, and in response to its position in a global- scaled niche model.Location India (Kashmir) and Switzerland (native range) and Australia and USA (Hawaii,...

Bats aloft: Variation in echolocation call structure at high altitudes

USDA-ARS?s Scientific Manuscript database

Bats alter their echolocation calls in response to changes in ecological and behavioral conditions, but little is known about how they adjust their call structure in response to changes in altitude. This study examines altitudinal variation in the echolocation calls of Brazilian free-tailed bats, T...

Large polarization gradients and temperature-stable responses in compositionally-graded ferroelectrics

DOE PAGES

Damodaran, Anoop R.; Pandya, Shishir; Qi, Yubo; ...

2017-05-10

A range of modern applications require large and tunable dielectric, piezoelectric or pyroelectric response of ferroelectrics. Such effects are intimately connected to the nature of polarization and how it responds to externally applied stimuli. Ferroelectric susceptibilities are, in general, strongly temperature dependent, diminishing rapidly as one transitions away from the ferroelectric phase transition (T C). In turn, researchers seek new routes to manipulate polarization to simultaneously enhance susceptibilities and broaden operational temperature ranges. Here, we demonstrate such a capability by creating composition and strain gradients in Ba 1-xSr xTiO 3 films which result in spatial polarization gradients as large asmore » 35 μC cm -2 across a 150 nm thick film. These polarization gradients allow for large dielectric permittivity with low loss (ε r≈775, tan δ<0.05), negligible temperature-dependence (13% deviation over 500 °C) and high-dielectric tunability (greater than 70% across a 300 °C range). The role of space charges in stabilizing polarization gradients is also discussed.« less

Large polarization gradients and temperature-stable responses in compositionally-graded ferroelectrics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Damodaran, Anoop R.; Pandya, Shishir; Qi, Yubo

A range of modern applications require large and tunable dielectric, piezoelectric or pyroelectric response of ferroelectrics. Such effects are intimately connected to the nature of polarization and how it responds to externally applied stimuli. Ferroelectric susceptibilities are, in general, strongly temperature dependent, diminishing rapidly as one transitions away from the ferroelectric phase transition (T C). In turn, researchers seek new routes to manipulate polarization to simultaneously enhance susceptibilities and broaden operational temperature ranges. Here, we demonstrate such a capability by creating composition and strain gradients in Ba 1-xSr xTiO 3 films which result in spatial polarization gradients as large asmore » 35 μC cm -2 across a 150 nm thick film. These polarization gradients allow for large dielectric permittivity with low loss (ε r≈775, tan δ<0.05), negligible temperature-dependence (13% deviation over 500 °C) and high-dielectric tunability (greater than 70% across a 300 °C range). The role of space charges in stabilizing polarization gradients is also discussed.« less

Extrapolating from local ecological processes to genus-wide patterns in colour polymorphism in South African Protea.

PubMed

Carlson, Jane E; Holsinger, Kent E

2015-05-07

Polymorphic traits are central to many fundamental discoveries in evolution, yet why they are found in some species and not others remains poorly understood. We use the African genus Protea-within which more than 40% of species have co-occurring pink and white floral colour morphs-to ask whether convergent evolution and ecological similarity could explain the genus-wide pattern of polymorphism. First, we identified environmental correlates of pink morph frequency across 28 populations of four species. Second, we determined whether the same correlates could predict species-level polymorphism and monomorphism across 31 species. We found that pink morph frequency increased with elevation in Protea repens and three section Exsertae species, increased eastward in P. repens, and increased with seed predation intensity in section Exsertae. For cross-species comparisons, populations of monomorphic pink species occurred at higher elevations than populations of monomorphic white species, and 18 polymorphic species spanned broader elevational gradients than 13 monomorphic species. These results suggest that divergent selection along elevational clines has repeatedly favoured polymorphism, and that more uniform selection in altitudinally restricted species may promote colour monomorphism. Our findings are, to our knowledge, the first to link selection acting within species to the presence and absence of colour polymorphism at broader phylogenetic scales. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Taxonomic and Functional Diversity of a Quercus pyrenaica Willd. Rhizospheric Microbiome in the Mediterranean Mountains

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cobo-Díaz, Jose F.; Fernández-González, Antonio J.; Villadas, Pablo J.

Altitude significantly affects vegetation growth and distribution, including the developmental stages of a forest. We used shotgun Illumina sequencing to analyze microbial community composition and functional potential in melojo-oak ( Quercus pyrenaica Willd.) rhizospheric soil for three different development stages along an altitudinal gradient: (a) a low altitude, non-optimal site for forest maintenance; (b) an intermediate altitude, optimal site for a forest; and (c) a high altitude, expansion site with isolated trees but without a real forest canopy. We observed that, at each altitude, the same microbial taxa appear both in the taxonomic analysis of the whole metagenome and inmore » the functional analysis of the methane, sulfur and nitrogen metabolisms. Although there were no major differences at the functional level, there were significant differences in the abundance of each taxon at the phylogenetic level between the rhizospheres of the forest (low and intermediate altitudes) and the expansion site. Proteobacteria and Actinobacteria were the most differentially abundant phyla in forest soils compared to the expansion site rhizosphere. Moreover, Verrucomicrobia, Bacteroidetes and Nitrospirae phyla were more highly represented in the non-forest rhizosphere. Our study suggests that rhizospheric microbial communities of the same tree species may be affected by development stage and forest canopy cover via changes in soil pH and the C/N ratio.« less

Contribution of arbuscular mycorrhizal fungi of sedges to soil aggregation along an altitudinal alpine grassland gradient on the Tibetan Plateau.

PubMed

Li, Xiaoliang; Zhang, Junling; Gai, Jingping; Cai, Xiaobu; Christie, Peter; Li, Xiaolin

2015-08-01

The diversity of arbuscular mycorrhizal fungi (AMF) in sedges on the Tibetan Plateau remains largely unexplored, and their contribution to soil aggregation can be important in understanding the ecological function of AMF in alpine ecosystems. Roots of Kobresia pygmaea C.B. Clarke and Carex pseudofoetida Kük. in alpine Kobresia pastures along an elevational transect (4149-5033 m) on Mount Mila were analysed for AMF diversity. A structural equation model was built to explore the contribution of biotic factors to soil aggregation. Sedges harboured abundant AMF communities covering seven families and some operational taxonomic units are habitat specific. The two plant species hosted similar AMF communities at most altitudes. The relative abundance of the two sedges contributed largely to soil macroaggregates, followed by extraradical mycorrhizal hyphae (EMH) and total glomalin-related soil protein (T-GRSP). The influence of plant richness was mainly due to its indirect influence on T-GRSP and EMH. There was a strong positive correlation between GRSP and soil total carbon and nitrogen. Our results indicate that mycorrhization might not be a major trait leading to niche differentiation of the two co-occurring sedge species. However, AMF contribute to soil aggregation and thus may have the potential to greatly influence C and N cycling in alpine grasslands. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

Geographic patterns and dynamics of Alaskan climate interpolated from a sparse station record

USGS Publications Warehouse

Fleming, Michael D.; Chapin, F. Stuart; Cramer, W.; Hufford, Gary L.; Serreze, Mark C.

2000-01-01

Data from a sparse network of climate stations in Alaska were interpolated to provide 1-km resolution maps of mean monthly temperature and precipitation-variables that are required at high spatial resolution for input into regional models of ecological processes and resource management. The interpolation model is based on thin-plate smoothing splines, which uses the spatial data along with a digital elevation model to incorporate local topography. The model provides maps that are consistent with regional climatology and with patterns recognized by experienced weather forecasters. The broad patterns of Alaskan climate are well represented and include latitudinal and altitudinal trends in temperature and precipitation and gradients in continentality. Variations within these broad patterns reflect both the weakening and reduction in frequency of low-pressure centres in their eastward movement across southern Alaska during the summer, and the shift of the storm tracks into central and northern Alaska in late summer. Not surprisingly, apparent artifacts of the interpolated climate occur primarily in regions with few or no stations. The interpolation model did not accurately represent low-level winter temperature inversions that occur within large valleys and basins. Along with well-recognized climate patterns, the model captures local topographic effects that would not be depicted using standard interpolation techniques. This suggests that similar procedures could be used to generate high-resolution maps for other high-latitude regions with a sparse density of data.

[Dung beetles (Coleoptera: Scarabaeinae) of the northwestern slope of the Sierra Nevada of Santa Marta, Colombia].

PubMed

Martínez, Neis J; García, Héctor; Pulido, Luz A; Ospino, Deibi; Harváez, Juan C

2009-01-01

The community structure of dung beetles in the middle and lower river basin of the Gaira river, Sierra Nevada de Santa Marta, Colombia, is described. Four sites were selected along an altitudinal gradient of 50-940 m for sampling from June to October, 2004. Dung beetles were captured using modified pitfall traps and manual recollections. We captured 7,872 individuals belonging to 29 species, distributed in 15 genera and five tribes of Scarabaeinae. Canthon and Onthophagus were the most diverse genera, each represented by six species. The sampled sites shared the following species: Onthophagus acuminatus Harold, O. clypeatus Blanchard, O. marginicollis Harold. Bocatoma was the most diverse site with 23 species; whereas Port Mosquito presented the highest abundance, with 3,262 individuals. Seven species represented 89% of all captures: Canthidium sp., Dichotomius sp., Uroxys sp. 1, Uroxys sp. 2, O. marginicollis, O. clypeatus and O. acuminatus. Of the 29 captured species, 17 belonged to the functional group of diggers and 10 were ball-rollers. We did not observe significant among-site differences in community structure. Abiotic factors such as altitude, temperature and humidity cannot explain observed variation in community structure across sites, indicating other variables such as vegetation cover, density of the vegetation and soil type may play a role in the community structure of these insects.

Taxonomic and Functional Diversity of a Quercus pyrenaica Willd. Rhizospheric Microbiome in the Mediterranean Mountains

DOE PAGES

Cobo-Díaz, Jose F.; Fernández-González, Antonio J.; Villadas, Pablo J.; ...

2017-10-12

Altitude significantly affects vegetation growth and distribution, including the developmental stages of a forest. We used shotgun Illumina sequencing to analyze microbial community composition and functional potential in melojo-oak ( Quercus pyrenaica Willd.) rhizospheric soil for three different development stages along an altitudinal gradient: (a) a low altitude, non-optimal site for forest maintenance; (b) an intermediate altitude, optimal site for a forest; and (c) a high altitude, expansion site with isolated trees but without a real forest canopy. We observed that, at each altitude, the same microbial taxa appear both in the taxonomic analysis of the whole metagenome and inmore » the functional analysis of the methane, sulfur and nitrogen metabolisms. Although there were no major differences at the functional level, there were significant differences in the abundance of each taxon at the phylogenetic level between the rhizospheres of the forest (low and intermediate altitudes) and the expansion site. Proteobacteria and Actinobacteria were the most differentially abundant phyla in forest soils compared to the expansion site rhizosphere. Moreover, Verrucomicrobia, Bacteroidetes and Nitrospirae phyla were more highly represented in the non-forest rhizosphere. Our study suggests that rhizospheric microbial communities of the same tree species may be affected by development stage and forest canopy cover via changes in soil pH and the C/N ratio.« less

Linking the Composition of Bacterial and Archaeal Communities to Characteristics of Soil and Flora Composition in the Atlantic Rainforest.

PubMed

Lima-Perim, Julia Elidia; Romagnoli, Emiliana Manesco; Dini-Andreote, Francisco; Durrer, Ademir; Dias, Armando Cavalcante Franco; Andreote, Fernando Dini

2016-01-01

The description of microbiomes as intrinsic fractions of any given ecosystem is an important issue, for instance, by linking their compositions and functions with other biotic and abiotic components of natural systems and hosts. Here we describe the archaeal and bacterial communities from soils of the Atlantic Rainforest in Brazil. Based on the comparison of three areas located along an altitudinal gradient-namely, Santa Virginia, Picinguaba and Restinga-we detected the most abundant groups of Bacteria (Acidobacteria and Proteobacteria) and Archaea (Thaumarchaeota, Crenarchaeota and Euryarchaeota). The particular composition of such communities in each of these areas was first evidenced by PCR-DGGE patterns [determined for Bacteria, Archaea and ammonia-oxidizing organisms-ammonia-oxidizing archaea (AOA) and bacteria (AOB)]. Moreover, sequence-based analysis provided a better resolution of communities, which indicated distinct frequencies of archaeal phyla and bacterial OTUs across areas. We found, as indicated by the Mantel test and multivariate analyses, a potential effect of the flora composition that outpaces the effect of soil characteristics (either physical and chemical) influencing the assembly of these microbial communities in soils. Our results indicate a collective role of the ecosystem underlying observed differences in microbial communities in these soils. Particularly, we posit that rainforest preservation also needs to take into account the maintenance of the soil biodiversity, as this is prompted to influence major processes that affect ecosystem functioning.

Intraspecific trait variation and covariation in a widespread tree species (Nothofagus pumilio) in southern Chile.

PubMed

Fajardo, Alex; Piper, Frida I

2011-01-01

• The focus of the trait-based approach to study community ecology has mostly been on trait comparisons at the interspecific level. Here we quantified intraspecific variation and covariation of leaf mass per area (LMA) and wood density (WD) in monospecific forests of the widespread tree species Nothofagus pumilio to determine its magnitude and whether it is related to environmental conditions and ontogeny. We also discuss probable mechanisms controlling the trait variation found. • We collected leaf and stem woody tissues from 30-50 trees of different ages (ontogeny) from each of four populations at differing elevations (i.e. temperatures) and placed at each of three locations differing in soil moisture. • The total variation in LMA (coefficient of variation (CV) = 21.14%) was twice that of WD (CV = 10.52%). The total variation in traits was never less than 23% when compared with interspecific studies. Differences in elevation (temperature) for the most part explained variation in LMA, while differences in soil moisture and ontogeny explained the variation in WD. Traits covaried similarly in the altitudinal gradient only. • Functional traits of N. pumilio exhibited nonnegligible variation; LMA varied for the most part with temperature, while WD mostly varied with moisture and ontogeny. We demonstrate that environmental variation can cause important trait variation without species turnover. © The Authors (2010). Journal compilation © New Phytologist Trust (2010).

Combining Step Gradients and Linear Gradients in Density.

PubMed

Kumar, Ashok A; Walz, Jenna A; Gonidec, Mathieu; Mace, Charles R; Whitesides, George M

2015-06-16

Combining aqueous multiphase systems (AMPS) and magnetic levitation (MagLev) provides a method to produce hybrid gradients in apparent density. AMPS—solutions of different polymers, salts, or surfactants that spontaneously separate into immiscible but predominantly aqueous phases—offer thermodynamically stable steps in density that can be tuned by the concentration of solutes. MagLev—the levitation of diamagnetic objects in a paramagnetic fluid within a magnetic field gradient—can be arranged to provide a near-linear gradient in effective density where the height of a levitating object above the surface of the magnet corresponds to its density; the strength of the gradient in effective density can be tuned by the choice of paramagnetic salt and its concentrations and by the strength and gradient in the magnetic field. Including paramagnetic salts (e.g., MnSO4 or MnCl2) in AMPS, and placing them in a magnetic field gradient, enables their use as media for MagLev. The potential to create large steps in density with AMPS allows separations of objects across a range of densities. The gradients produced by MagLev provide resolution over a continuous range of densities. By combining these approaches, mixtures of objects with large differences in density can be separated and analyzed simultaneously. Using MagLev to add an effective gradient in density also enables tuning the range of densities captured at an interface of an AMPS by simply changing the position of the container in the magnetic field. Further, by creating AMPS in which phases have different concentrations of paramagnetic ions, the phases can provide different resolutions in density. These results suggest that combining steps in density with gradients in density can enable new classes of separations based on density.

Mitochondrial phylogeography and population structure of the cattle tick Rhipicephalus appendiculatus in the African Great Lakes region.

PubMed

Amzati, Gaston S; Pelle, Roger; Muhigwa, Jean-Berckmans B; Kanduma, Esther G; Djikeng, Appolinaire; Madder, Maxime; Kirschvink, Nathalie; Marcotty, Tanguy

2018-05-31

The ixodid tick Rhipicephalus appendiculatus is the main vector of Theileria parva, wich causes the highly fatal cattle disease East Coast fever (ECF) in sub-Saharan Africa. Rhipicephalus appendiculatus populations differ in their ecology, diapause behaviour and vector competence. Thus, their expansion in new areas may change the genetic structure and consequently affect the vector-pathogen system and disease outcomes. In this study we investigated the genetic distribution of R. appendiculatus across agro-ecological zones (AEZs) in the African Great Lakes region to better understand the epidemiology of ECF and elucidate R. appendiculatus evolutionary history and biogeographical colonization in Africa. Sequencing was performed on two mitochondrial genes (cox1 and 12S rRNA) of 218 ticks collected from cattle across six AEZs along an altitudinal gradient in the Democratic Republic of Congo, Rwanda, Burundi and Tanzania. Phylogenetic relationships between tick populations were determined and evolutionary population dynamics models were assessed by mismach distribution. Population genetic analysis yielded 22 cox1 and 9 12S haplotypes in a total of 209 and 126 nucleotide sequences, respectively. Phylogenetic algorithms grouped these haplotypes for both genes into two major clades (lineages A and B). We observed significant genetic variation segregating the two lineages and low structure among populations with high degree of migration. The observed high gene flow indicates population admixture between AEZs. However, reduced number of migrants was observed between lowlands and highlands. Mismatch analysis detected a signature of rapid demographic and range expansion of lineage A. The star-like pattern of isolated and published haplotypes indicates that the two lineages evolve independently and have been subjected to expansion across Africa. Two sympatric R. appendiculatus lineages occur in the Great Lakes region. Lineage A, the most diverse and ubiquitous, has experienced rapid population growth and range expansion in all AEZs probably through cattle movement, whereas lineage B, the less abundant, has probably established a founder population from recent colonization events and its occurrence decreases with altitude. These two lineages are sympatric in central and eastern Africa and allopatric in southern Africa. The observed colonization pattern may strongly affect the transmission system and may explain ECF endemic instability in the tick distribution fringes.

Using age of colonizing douglas-fir for the dating of young geomorphic surfaces: a case study

USGS Publications Warehouse

Pierson, Thomas C.

2013-01-01

Dating of many types of young (<500 year), dynamic, geomorphic landforms (e.g. mass-movement erosional tracks and deposits, alluvial terraces, flood plains, etc.) for purposes of hazard assessment and mitigation commonly requires greater dating precision than is available through radiocarbon dating or other methods. Ages of trees growing on landform surfaces have been used in a number of studies to estimate the time of landform creation or surface clearing, but the time lag between surface formation or disturbance and the reestablishment of trees can vary from 1 to more than 200 years (Desloges and Ryder 1990; Frenzen et al. 1988, 2005; Larsen and Bliss 1998; McCarthy and Luckman 1993; Sigafoos and Hendricks 1969; Winter et al. 2002). Appropriate lag times for selected tree species and for particular climatic and altitudinal ranges must be determined for the method to be useful.

Strong upslope shifts in Chimborazo's vegetation over two centuries since Humboldt.

PubMed

Morueta-Holme, Naia; Engemann, Kristine; Sandoval-Acuña, Pablo; Jonas, Jeremy D; Segnitz, R Max; Svenning, Jens-Christian

2015-10-13

Global climate change is driving species poleward and upward in high-latitude regions, but the extent to which the biodiverse tropics are similarly affected is poorly known due to a scarcity of historical records. In 1802, Alexander von Humboldt ascended the Chimborazo volcano in Ecuador. He recorded the distribution of plant species and vegetation zones along its slopes and in surrounding parts of the Andes. We revisited Chimborazo in 2012, precisely 210 y after Humboldt's expedition. We documented upward shifts in the distribution of vegetation zones as well as increases in maximum elevation limits of individual plant taxa of >500 m on average. These range shifts are consistent with increased temperatures and glacier retreat on Chimborazo since Humboldt's study. Our findings provide evidence that global warming is strongly reshaping tropical plant distributions, consistent with Humboldt's proposal that climate is the primary control on the altitudinal distribution of vegetation.

Strong upslope shifts in Chimborazo's vegetation over two centuries since Humboldt

PubMed Central

Morueta-Holme, Naia; Engemann, Kristine; Sandoval-Acuña, Pablo; Jonas, Jeremy D.; Segnitz, R. Max; Svenning, Jens-Christian

2015-01-01

Global climate change is driving species poleward and upward in high-latitude regions, but the extent to which the biodiverse tropics are similarly affected is poorly known due to a scarcity of historical records. In 1802, Alexander von Humboldt ascended the Chimborazo volcano in Ecuador. He recorded the distribution of plant species and vegetation zones along its slopes and in surrounding parts of the Andes. We revisited Chimborazo in 2012, precisely 210 y after Humboldt’s expedition. We documented upward shifts in the distribution of vegetation zones as well as increases in maximum elevation limits of individual plant taxa of >500 m on average. These range shifts are consistent with increased temperatures and glacier retreat on Chimborazo since Humboldt’s study. Our findings provide evidence that global warming is strongly reshaping tropical plant distributions, consistent with Humboldt’s proposal that climate is the primary control on the altitudinal distribution of vegetation. PMID:26371298

Micro- and macro-geographic scale effect on the molecular imprint of selection and adaptation in Norway spruce.

PubMed

Scalfi, Marta; Mosca, Elena; Di Pierro, Erica Adele; Troggio, Michela; Vendramin, Giovanni Giuseppe; Sperisen, Christoph; La Porta, Nicola; Neale, David B

2014-01-01

Forest tree species of temperate and boreal regions have undergone a long history of demographic changes and evolutionary adaptations. The main objective of this study was to detect signals of selection in Norway spruce (Picea abies [L.] Karst), at different sampling-scales and to investigate, accounting for population structure, the effect of environment on species genetic diversity. A total of 384 single nucleotide polymorphisms (SNPs) representing 290 genes were genotyped at two geographic scales: across 12 populations distributed along two altitudinal-transects in the Alps (micro-geographic scale), and across 27 populations belonging to the range of Norway spruce in central and south-east Europe (macro-geographic scale). At the macrogeographic scale, principal component analysis combined with Bayesian clustering revealed three major clusters, corresponding to the main areas of southern spruce occurrence, i.e. the Alps, Carpathians, and Hercynia. The populations along the altitudinal transects were not differentiated. To assess the role of selection in structuring genetic variation, we applied a Bayesian and coalescent-based F(ST)-outlier method and tested for correlations between allele frequencies and climatic variables using regression analyses. At the macro-geographic scale, the F(ST)-outlier methods detected together 11 F(ST)-outliers. Six outliers were detected when the same analyses were carried out taking into account the genetic structure. Regression analyses with population structure correction resulted in the identification of two (micro-geographic scale) and 38 SNPs (macro-geographic scale) significantly correlated with temperature and/or precipitation. Six of these loci overlapped with F(ST)-outliers, among them two loci encoding an enzyme involved in riboflavin biosynthesis and a sucrose synthase. The results of this study indicate a strong relationship between genetic and environmental variation at both geographic scales. It also suggests that an integrative approach combining different outlier detection methods and population sampling at different geographic scales is useful to identify loci potentially involved in adaptation.

Micro- and Macro-Geographic Scale Effect on the Molecular Imprint of Selection and Adaptation in Norway Spruce

PubMed Central

Scalfi, Marta; Mosca, Elena; Di Pierro, Erica Adele; Troggio, Michela; Vendramin, Giovanni Giuseppe; Sperisen, Christoph; La Porta, Nicola; Neale, David B.

2014-01-01

Forest tree species of temperate and boreal regions have undergone a long history of demographic changes and evolutionary adaptations. The main objective of this study was to detect signals of selection in Norway spruce (Picea abies [L.] Karst), at different sampling-scales and to investigate, accounting for population structure, the effect of environment on species genetic diversity. A total of 384 single nucleotide polymorphisms (SNPs) representing 290 genes were genotyped at two geographic scales: across 12 populations distributed along two altitudinal-transects in the Alps (micro-geographic scale), and across 27 populations belonging to the range of Norway spruce in central and south-east Europe (macro-geographic scale). At the macrogeographic scale, principal component analysis combined with Bayesian clustering revealed three major clusters, corresponding to the main areas of southern spruce occurrence, i.e. the Alps, Carpathians, and Hercynia. The populations along the altitudinal transects were not differentiated. To assess the role of selection in structuring genetic variation, we applied a Bayesian and coalescent-based F ST-outlier method and tested for correlations between allele frequencies and climatic variables using regression analyses. At the macro-geographic scale, the F ST-outlier methods detected together 11 F ST-outliers. Six outliers were detected when the same analyses were carried out taking into account the genetic structure. Regression analyses with population structure correction resulted in the identification of two (micro-geographic scale) and 38 SNPs (macro-geographic scale) significantly correlated with temperature and/or precipitation. Six of these loci overlapped with F ST-outliers, among them two loci encoding an enzyme involved in riboflavin biosynthesis and a sucrose synthase. The results of this study indicate a strong relationship between genetic and environmental variation at both geographic scales. It also suggests that an integrative approach combining different outlier detection methods and population sampling at different geographic scales is useful to identify loci potentially involved in adaptation. PMID:25551624

Characterizing Betula litwinowii seedling microsites at the alpine-treeline ecotone, central Greater Caucasus Mountains, Georgia

Treesearch

Nicole M Hughes; Daniel M. Johnson; Maia Akhalkatsi; Otar Abdaladze

2009-01-01

Seedling establishment is an important factor dictating the altitudinal limits of treeline species. Factors that affect seedling mortality and survival, however, have yet to be fully characterized, especially for deciduous treeline species. Here we describe microsite characteristics of successfully established Betula litwinowii seedlings at the...

Infiltration on mountain slopes: a comparison of three environments.

Treesearch

Carol P. Harden*; P. Delmas Scruggs

2003-01-01

Water is well established as a major driver of the geomorphic change that eventually reduces mountains to lower relief landscapes. Nonetheless, within the altitudinal limits of continuous vegetation in humid climates, water is also an essential factor in slope stability. In this paper, we present results from field experiments to determine infiltration rates at...

Right up There: Hemispatial and Hand Asymmetries of Altitudinal Pseudoneglect

ERIC Educational Resources Information Center

Suavansri, Ketchai; Falchook, Adam D.; Williamson, John B.; Heilman, Kenneth M.

2012-01-01

Background: Pseudoneglect is a normal left sided spatial bias observed with attempted bisections of horizontal lines and a normal upward bias observed with attempted bisections of vertical lines. Horizontal pseudoneglect has been attributed to right hemispheric dominance for the allocation of attention. The goal of this study was to test the…

Altitudinal variation of secondary metabolite profiles in flowering heads of Arnica montana cv. ARBO.

PubMed

Spitaler, Renate; Schlorhaufer, P Daniel; Ellmerer, Ernst P; Merfort, Irmgard; Bortenschlager, Sigmar; Stuppner, Hermann; Zidorn, Christian

2006-02-01

The altitudinal variation on the contents of secondary metabolites in flowering heads of Arnica montana was assessed. Plants of A. montana cultivar ARBO were grown in nine experimental plots at altitudes between 590 and 2230m at Mount Patscherkofel near Innsbruck/Austria. The total contents of sesquiterpene lactones and flavonoids were not positively correlated with the altitude of the growing site. However, the proportion of flavonoids with vicinal free hydroxy groups in ring B to flavonoids lacking this feature significantly increased with elevation. Additionally, the level of caffeic acid derivatives also positively correlated with the altitude of the growing site. In particular amounts of 1-methoxyoxaloyl-3,5-dicaffeoylquinic acid significantly increased in higher sites and samples from the summit region contained 85% more of this compound than samples from valley sites. These results are discussed with regards to chemosystematic studies comparing samples collected in different altitudes as well as in the light of a UV-B protective and radical scavenging function of phenolics and their significance for plant life in environments with elevated UV-B radiation.

Restoration of movement patterns of the Hawaiian Goose

USGS Publications Warehouse

Hess, Steven C.; Leopold, Christina R.; Misajon, Kathleen; Hu, Darcy; Jeffrey, John J.

2012-01-01

We used visual observations of banded individuals and satellite telemetry from 2007 to 2011 on Hawai′i Island to document movement patterns of the Hawaiian Goose (Branta sandvicensis), commonly known as Nene. Visual observations of numbered leg bands identified >19% and ≤10% of 323 geese at one of two breeding sites and one of two distant non-breeding areas during 2007-2011. We used satellite telemetry to document movement patterns of 10 male Nene from 2009 to 2011, and log-linear models to quantify the magnitude and individual differences in altitudinal migration. Two subpopulations of Nene moved 974.4 m (95% CI ± 22.0) and 226.4 m (95% CI ± 40.7) in elevation between seasons on average, from high-elevation shrublands during the non-breeding season of May-August, to lower-elevation breeding and molting areas in September-April. Traditional movement patterns were thought to be lost until recently, but the movement pattern we documented with satellite telemetry was similar to altitudinal migration described by early naturalists in Hawai′i prior to the severe population decline of Nene in the 20th century.

Influence of altitudinal variation on the content of phenolic compounds in wild populations of Calluna vulgaris, Sambucus nigra, and Vaccinium myrtillus.

PubMed

Rieger, Gudrun; Müller, Maria; Guttenberger, Helmut; Bucar, Franz

2008-10-08

This study deals with the effect of altitudinal variation on the content of phenolic compounds in three traditional herbal plants, which are also consumed as food in Central Europe. Herbs of Calluna vulgaris (L.) HULL, flowers and fruits of Sambucus nigra L., and berries of Vaccinium myrtillus L. collected in the Naturpark Solktaler (Austria) were extracted using accelerated solvent extraction (ASE). Identification and quantification of the constituents in the polar extracts (methanol 80%, v/v) were achieved by means of RP-HPLC-PDA and/or LC-PDA-MS analysis with external standards. 3,5- O-Dicaffeoylquinic acid was identified in flowers of S. nigra for the first time. Rising concentrations of flavonoids and especially flavonol-3- O-glycosides with adjacent hydroxyl groups in ring B in C. vulgaris and S. nigra with increasing altitude were observed. Anthocyanins from the berries of both S. nigra and V. myrtillus occurred in decreasing amounts with rising altitude. C. vulgaris showed the best radical scavenging capacity based on the DPPH assay.

A microfluidic multi-injector for gradient generation.

PubMed

Chung, Bong Geun; Lin, Francis; Jeon, Noo Li

2006-06-01

This paper describes a microfluidic multi-injector (MMI) that can generate temporal and spatial concentration gradients of soluble molecules. Compared to conventional glass micropipette-based methods that generate a single gradient, the MMI exploits microfluidic integration and actuation of multiple pulsatile injectors to generate arbitrary overlapping gradients that have not previously been possible. The MMI device is fabricated in poly(dimethylsiloxane) (PDMS) using multi-layer soft lithography and consists of fluidic channels and control channels with pneumatically actuated on-chip barrier valves. Repetitive actuation of on-chip valves control pulsatile release of solution that establishes microscopic chemical gradients around the orifice. The volume of solution released per actuation cycle ranged from 30 picolitres to several hundred picolitres and increased linearly with the duration of valve opening. The shape of the measured gradient profile agreed closely with the simulated diffusion profile from a point source. Steady state gradient profiles could be attained within 10 minutes, or less with an optimized pulse sequence. Overlapping gradients from 2 injectors were generated and characterized to highlight the advantages of MMI over conventional micropipette assays. The MMI platform should be useful for a wide range of basic and applied studies on chemotaxis and axon guidance.

Systematic generation of buffer systems for pH gradient ion exchange chromatography and their application.

PubMed

Kröner, Frieder; Hubbuch, Jürgen

2013-04-12

pH gradient protein separations are widely used techniques in the field of protein analytics, of which isoelectric focusing is the most well known application. The chromatographic variant, based on the formation of pH gradients in ion exchange columns is only rarely applied due to the difficulties to form controllable, linear pH gradients over a broad pH range. This work describes a method for the systematic generation of buffer compositions with linear titration curves, resulting in well controllable pH gradients. To generate buffer compositions with linear titration curves an in silico method was successfully developed. With this tool, buffer compositions for pH gradient ion exchange chromatography with pH ranges spanning up to 7.5 pH units were established and successfully validated. Subsequently, the buffer systems were used to characterize the elution behavior of 22 different model proteins in cation and anion exchange pH gradient chromatography. The results of both chromatographic modes as well as isoelectric focusing were compared to describe differences in between the methods. Copyright © 2013 Elsevier B.V. All rights reserved.

Characterization of thermotropism in primary roots of maize: dependence on temperature and temperature gradient, and interaction with gravitropism

NASA Technical Reports Server (NTRS)

Poff, K. L.

1991-01-01

Thermotropism in primary roots of Zea mays L. was studied with respect to gradient strength (degrees C cm-1), temperature of exposure within a gradient, pre-treatment temperature, and gravitropic stimulation. The magnitude of the response decreased with gradient strength. Maximum thermotropism was independent of gradient strength and pre-treatment temperature. The range of temperature for positive and negative thermotropism did not change with pre-treatment temperature. However, the exact range of temperatures for positive and negative thermotropism varied with gradient strengths. In general, temperatures of exposure lower than 25 degrees C resulted in positive tropic responses while temperatures of exposure of 39 degrees C or more resulted in negative tropic responses. Thermotropism was shown to modify and reverse the normal gravitropic curvature of a horizontal root when thermal gradients were applied opposite the 1 g vector. It is concluded that root thermotropism is a consequence of thermal sensing and that the curvature of the primary root results from the interaction of the thermal and gravitational sensing systems.

Altitudinal characteristics of atmospheric deposition of aerosols in mountainous regions: Lessons from the Fukushima Daiichi Nuclear Power Station accident.

PubMed

Sanada, Yukihisa; Katata, Genki; Kaneyasu, Naoki; Nakanishi, Chika; Urabe, Yoshimi; Nishizawa, Yukiyasu

2018-03-15

To understand the formation process of radiologically contaminated areas in eastern Japan caused by the Fukushima Daiichi Nuclear Power Station (FDNPS) accident, the deposition mechanisms over complex topography are the key factors to be investigated. To characterize the atmospheric deposition processes of radionuclides over complex mountainous topography, we investigated the altitudinal distributions of the radiocesium deposited during the accident. In five selected areas, altitudinal characteristics of the air dose rates observed using airborne surveys were analyzed. To examine the deposition mechanisms, we supplementarily used vertical profiles of radiocesium deposition in each area calculated in the latest atmospheric dispersion model. In southern Iwate, the vertical profile of the observed air dose rate was uniform regardless of altitude. In western Tochigi, the areas with the highest levels of contamination were characteristically distributed in the middle of the mountains, while in southern Fukushima, the areas with the highest contamination levels were enhanced near the summits of mountains. In central Fukushima, high air dose rates were limited to the bottoms of basin-like valley. In the region northwest of FDNPS, the air dose rate was the highest at the bottom of valley topography and decreased gradually with altitude. The simulation results showed that calculated wet deposition and observed vertical profiles of total deposition were similar in areas of southern Iwate and northwest of FDNPS qualitatively, suggesting that the dominant deposition mechanism was wet deposition. In contrast, the atmospheric dispersion model failed to reproduce either the timing of precipitation events or vertical profiles of radiocesium deposition in three other areas. Although it was difficult to elucidate the deposition mechanisms in these areas due to uncertainties of the present model results, potential mechanisms such as cloud water deposition were still proposed based on circumstantial evidences of limited meteorological data during the early stage of the accident. Copyright © 2017 Elsevier B.V. All rights reserved.

Size exclusion chromatography-gradients, an alternative approach to polymer gradient chromatography: 2. Separation of poly(meth)acrylates using a size exclusion chromatography-solvent/non-solvent gradient.

PubMed

Schollenberger, Martin; Radke, Wolfgang

2011-10-28

A gradient ranging from methanol to tetrahydrofuran (THF) was applied to a series of poly(methyl methacrylate) (PMMA) standards, using the recently developed concept of SEC-gradients. Contrasting to conventional gradients the samples eluted before the solvent, i.e. within the elution range typical for separations by SEC, however, the high molar mass PMMAs were retarded as compared to experiments on the same column using pure THF as the eluent. The molar mass dependence on retention volume showed a complex behaviour with a nearly molar mass independent elution for high molar masses. This molar mass dependence was explained in terms of solubility and size exclusion effects. The solubility based SEC-gradient was proven to be useful to separate PMMA and poly(n-butyl crylate) (PnBuA) from a poly(t-butyl crylate) (PtBuA) sample. These samples could be separated neither by SEC in THF, due to their very similar hydrodynamic volumes, nor by an SEC-gradient at adsorbing conditions, due to a too low selectivity. The example shows that SEC-gradients can be applied not only in adsorption/desorption mode, but also in precipitation/dissolution mode without risking blocking capillaries or breakthrough peaks. Thus, the new approach is a valuable alternative to conventional gradient chromatography. Copyright © 2011 Elsevier B.V. All rights reserved.

Avian disease and mosquito vectors in the Kahuku unit of Hawai`i Volcanoes National Park and Ka`u Forest Reserve

USGS Publications Warehouse

Gaudioso, Jacqueline; Lapointe, Dennis; Atkinson, Carter T.; Egan, Ariel N.

2015-01-01

While avian disease has been well-studied in windward forests of Hawai‘i Island, there have been few studies in leeward Ka‘u. We surveyed four altitudinal sites ranging from 1,200 to 2,200 m asl in the Kahuku Unit of Hawai‘i Volcanoes National Park (Kahuku) and three altitudinal sites ranging from 1,200 to 1,500 m asl in the Ka‘u Forest Reserve (Ka‘u) for the prevalence of avian disease and presence of mosquitoes. We collected blood samples from native and non-native forest birds and screened for avian malaria (Plasmodium relictum) using PCR diagnostics. We examined birds for signs of avian pox (Avipoxvirus sp.), knemidokoptic mange (Knemidokoptes jamaicensis) and feather ectoparasites. We also trapped adult mosquitoes (Culex quinquefasciatus and Aedes japonicus japonicus) and surveyed for available larval habitat. Between September, 2012 and October, 2014, we completed 3,219 hours of mist-netting in Kahuku capturing 515 forest birds and 3,103 hours of mist-netting in Ka‘u capturing 270 forest birds. We screened 750 blood samples for avian malaria. Prevalence of avian malaria in all species was higher in Ka‘u than Kahuku when all sites were combined for each tract. Prevalence of avian malaria in resident Hawai‘i ‘amakihi (Chlorodrepanis virens) was greatest at the lowest elevation sites in Kahuku (26%; 1,201 m asl) and Ka‘u (42%; 1,178 m asl) and in general, prevalence decreased with increasing elevation and geographically from east to west. Significantly higher prevalence was seen in Ka‘u at comparable low and mid elevation sites but not at comparable high elevation sites. The overall presumptive pox prevalence was 1.7% (13/785) for both tracts, and it was higher in native birds than non-native birds, but it was not significant. Presumptive knemidokoptic mange was detected at two sites in lower elevation Kahuku, with prevalence ranging from 2‒4%. The overall prevalence of ectoparasites (Analges and Proctophyllodes spp.) was 6.7% (53/785). The site with the highest prevalence was Lower Glover in Kahuku (7.2%; 10/138) and Maka‘alia in Ka‘u. In general, mosquito larval habitat was more prevalent at lower elevation sites than higher elevation sites within the Kahuku—Ka‘u landscape, and more prevalent in Ka‘u than Kahuku. We observed significantly more available larval mosquito habitat in total belt transect plots in Ka‘u than Kahuku for both hapu‘u cavities (Χ2 = 47.06, df = 1, p < 0.01) and other habitat types combined (i.e., ground pools, rock holes, tree holes) (Χ2 = 104.35, df = 1, p < 0.01). Mosquitoes were most abundant at low elevation Kahuku, but were captured at all sites up to 1,532 m asl in Kahuku. The malarial infection rate of live mosquitoes was 21% (39/186) at Kahuku and 25% (2/8) at Ka‘u. There were 19 times more larval habitats available in Ka‘u than Kahuku on survey transects, yet we captured 53 times more C. quinquefasciatus mosquitoes in Kahuku. We captured very few adult A. j. japonicus across the landscape (Ntotal = 6) and no Aedes albopictus were detected in this study. Larval surveys along ranch roads and infrastructure revealed that ground pools along rutted, overgrown ranch roads were the likely source of Kahuku mosquitoes. We did not find mosquito larvae associated with ranching infrastructure. Unlike the low elevation forests on windward Hawai‘i Island, avian malaria prevalence, mosquito abundance, and the density of available larval habitat in Kahuku and Ka‘u were relatively low. Although altitudinal variations in climate appear to be the primary factors limiting the distribution of avian disease, habitat type, avian movements, human activity, and feral pig (Sus scrofa) management all may play important roles in determining the prevalence of avian malaria across the Kahuku—Ka‘u landscape.

Disentangling climatic versus biotic drivers of tree range constraints: Broad scale tradeoffs between climate and competion rarely explain local range boundaries

NASA Astrophysics Data System (ADS)

Anderegg, L. D. L.; Hillerislambers, J.

2016-12-01

Accurate prediction of climatically-driven range shifts requires knowledge of the dominant forces constraining species ranges, because climatically controlled range boundaries will likely behave differently from biotically controlled range boundaries in a changing climate. Yet the roles of climatic constraints (due to species physiological tolerance) versus biotic constraints (caused by species interactions) on geographic ranges are largely unknown, infusing large uncertainty into projections of future range shifts. Plant species ranges across strong climatic gradients such as elevation gradients are often assumed to represent a tradeoff between climatic constraints on the harsh side of the range and biotic constraints (often competitive constraints) on the climatically benign side. To test this assumption, we collected tree cores from across the elevational range of the three dominant tree species inhabiting each of three climatically disparate mountain slopes and assessed climatic versus competitive constraints on growth at each species' range margins. Across all species and mountains, we found evidence for a tradeoff between climatic and competitve growth constraints. We also found that some individual species did show an apparent trade-off between a climatic constraint at one range margin and a competitive constraint at the other. However, even these simple elevation gradients resulted in complex interactions between temperature, moisture, and competitive constraints such that a climate-competition tradeoff did not explain range constraints for many species. Our results suggest that tree species can be constrained by a simple trade-off between climate and competition, but that the intricacies of real world climate gradients complicate the application of this theory even in apparently harsh environments, such as near high elevation tree line.

Escaping to the summits: phylogeography and predicted range dynamics of Cerastium dinaricum, an endangered high mountain plant endemic to the western Balkan Peninsula.

PubMed

Kutnjak, Denis; Kuttner, Michael; Niketić, Marjan; Dullinger, Stefan; Schönswetter, Peter; Frajman, Božo

2014-09-01

The Balkans are a major European biodiversity hotspot, however, almost nothing is known about processes of intraspecific diversification of the region's high-altitude biota and their reaction to the predicted global warming. To fill this gap, genome size measurements, AFLP fingerprints, plastid and nuclear sequences were employed to explore the phylogeography of Cerastium dinaricum. Range size changes under future climatic conditions were predicted by niche-based modeling. Likely the most cold-adapted plant endemic to the Dinaric Mountains in the western Balkan Peninsula, the species has conservation priority in the European Union as its highly fragmented distribution range includes only few small populations. A deep phylogeographic split paralleled by divergent genome size separates the populations into two vicariant groups. Substructure is pronounced within the southeastern group, corresponding to the area's higher geographic complexity. Cerastium dinaricum likely responded to past climatic oscillations with altitudinal range shifts, which, coupled with high topographic complexity of the region and warmer climate in the Holocene, sculptured its present fragmented distribution. Field observations revealed that the species is rarer than previously assumed and, as shown by modeling, severely endangered by global warming as viable habitat was predicted to be reduced by more than 70% by the year 2080. Copyright © 2014 Elsevier Inc. All rights reserved.

Effects of horizontal refractivity gradients on the accuracy of laser ranging to satellites

NASA Technical Reports Server (NTRS)

Gardner, C. S.

1976-01-01

Numerous formulas have been developed to partially correct laser ranging data for the effects of atmospheric refraction. All the formulas assume the atmospheric refractivity profile is spherically symmetric. The effects of horizontal refractivity gradients are investigated by ray tracing through spherically symmetric and three-dimensional refractivity profiles. The profiles are constructed from radiosonde data. The results indicate that the horizontal gradients introduce an rms error of approximately 3 cm when the satellite is near 10 deg elevation. The error decreases to a few millimeters near zenith.

Aircraft symmetric flight optimization. [gradient techniques for supersonic aircraft control

NASA Technical Reports Server (NTRS)

Falco, M.; Kelley, H. J.

1973-01-01

Review of the development of gradient techniques and their application to aircraft optimal performance computations in the vertical plane of flight. Results obtained using the method of gradients are presented for attitude- and throttle-control programs which extremize the fuel, range, and time performance indices subject to various trajectory and control constraints, including boundedness of engine throttle control. A penalty function treatment of state inequality constraints which generally appear in aircraft performance problems is outlined. Numerical results for maximum-range, minimum-fuel, and minimum-time climb paths for a hypothetical supersonic turbojet interceptor are presented and discussed. In addition, minimum-fuel climb paths subject to various levels of ground overpressure intensity constraint are indicated for a representative supersonic transport. A variant of the Gel'fand-Tsetlin 'method of ravines' is reviewed, and two possibilities for further development of continuous gradient processes are cited - namely, a projection version of conjugate gradients and a curvilinear search.

Postbreeding elevational movements of western songbirds in Northern California and Southern Oregon

Treesearch

Andrew Wiegardt; Jared Wolfe; C. John Ralph; Jaime L. Stephens; John Alexander

2017-01-01

Migratory species employ a variety of strategies to meet energetic demands of postbreeding molt. As such, at least a few species of western Neotropical migrants are known to undergo short-distance upslope movements to locations where adults molt body and flight feathers (altitudinal molt migration). Given inherent difficulties in measuring subtle movements of...

Altitudinal genetic variation among Pinus oocarpa populations in Michoacan, Mexico: implications for seed zoning, conservation, tree breeding and global warming

Treesearch

Cuauhtemoc Saenz-Romero; R. Ricardo Guzman-Reyna; Gerald E. Rehfeldt

2006-01-01

Pinus oocarpa has a large natural distribution in the sub-tropical forests of Mexico. Populations, however, are rapidly disappearing particularly in the Michoacan State as native forests are converted to avocado (Persea sp.) orchards.We investigated the patterning of genetic variation among P. oocarpa populations...

Species abundances, guild dominance patterns, and community structure of breeding riparian birds

Treesearch

Deborah M. Finch

1989-01-01

I investigated trends in bird species populations, guild structure, and bird communities along a riparian altitudinal cline in the Medicine Bow National Forest of southeastern Wyoming. Streamside habitats were divided into three elevational zones: low-elevation (2050 to 2260 m) cottonwood zone, mid-elevation (2290 to 2530 m) mixed shrub willow zone, and high elevation...

Provisional tree seed zones and transfer guidelines for Alaska.

Treesearch

John N. Alden

1991-01-01

Four hundred and eighty-six provisional tree seed zones were delineated within 24 physiographic and climatic regions of Alaska and western Yukon Territory Estimated forest and potential forest land within altitudinal limits of tree species in Alaska was 51,853,000 hectares (128,130,000 acres) Seed transfer guidelines and standard labeling of seed collections are...

Influence of altitude and aspect on daily variations in factors of forest fire danger

Treesearch

G. Lloyd. Hayes

1941-01-01

Altitude, in broad subdivisions, exerts recognized and well-understood effects on climate. Aspect further modifies the altitudinal influence. Many publications have dealt with the interrelations of these geographic factors with climate and life zones or have discussed variations of individual weather elements as influenced by local altitude and aspect differences and...

Present heat flow and paleo-geothermal regime in the Canadian Arctic margin: analysis of industrial thermal data and coalification gradients

NASA Astrophysics Data System (ADS)

Majorowicz, Jacek A.; Embry, Ashton F.

1998-06-01

Calculations of the present geothermal gradient and terrestrial heat flow were made on 156 deep wells of the Canadian Arctic Archipelago. Corrected bottom hole temperature (BHT) data and drill stem test (DST) temperatures were used to determine the thermal gradients for sites for which the quality of data was sufficient. Thermal gradients evaluated for depths below the base of permafrost for the onshore wells and below sea bottom for the offshore wells were combined with the estimates of effective thermal conductivity to approximate heat flow for these sites. The present geothermal gradient is in the 15-50 mK/m range (mean = 31 ± 7 mK/m). Present heat flow is mainly in the 35-90 mW/m 2 range (mean = 53 ± 12 mW/m 2). Maps of the present geothermal gradient and present heat flow have been constructed for the basin. The analysis of vitrinite reflectance profiles and the calculation of logarithmic coalification gradients for 101 boreholes in the Sverdrup Basin showed large variations related in many cases to regional variations of present terrestrial heat flow. Paleo-geothermal gradients estimated from these data are mostly in the range of 15-50 mK/m (mean = 28 ± 9 mK/m) and paleo-heat flow is in the 40-90 mW/m 2 range (mean = 57 ± 18 mW/m 2) related to the time of maximum burial in the Early Tertiary. Mean values of the present heat flow and paleo-heat flow for the Sverdrup Basin are almost identical considering the uncertainties of the methods used (53 ± 12 versus 57 ± 18 mW/m 2, respectively). Present geothermal gradients and paleo-geothermal gradients are also close when means are compared (31 ± 7 versus 28 ± 9 mK/m respectively). A zone of high present heat flow and a paleo-heat flow zone coincide in places with the northeastern-southwestern incipient rift landward of the Arctic margin first described by Balkwill and Fox (1982). Correlation between present heat flow and paleo-heat flow for the time of maximum burial in the earliest Tertiary suggests that the high heat flow zone has prevailed since that time.

The evolution of conditional dispersal and reproductive isolation along environmental gradients

PubMed Central

Payne, Joshua L.; Mazzucco, Rupert; Dieckmann, Ulf

2011-01-01

Dispersal modulates gene flow throughout a population’s spatial range. Gene flow affects adaptation at local spatial scales, and consequently impacts the evolution of reproductive isolation. A recent theoretical investigation has demonstrated that local adaptation along an environmental gradient, facilitated by the evolution of limited dispersal, can lead to parapatric speciation even in the absence of assortative mating. This and other studies assumed unconditional dispersal, so individuals start dispersing without regard to local environmental conditions. However, many species disperse conditionally; their propensity to disperse is contingent upon environmental cues, such as the degree of local crowding or the availability of suitable mates. Here, we use an individual-based model in continuous space to investigate by numerical simulation the relationship between the evolution of threshold-based conditional dispersal and parapatric speciation driven by frequency-dependent competition along environmental gradients. We find that, as with unconditional dispersal, parapatric speciation occurs under a broad range of conditions when reproduction is asexual, and under a more restricted range of conditions when reproduction is sexual. In both the asexual and sexual cases, the evolution of conditional dispersal is strongly influenced by the slope of the environmental gradient: shallow environmental gradients result in low dispersal thresholds and high dispersal distances, while steep environmental gradients result in high dispersal thresholds and low dispersal distances. The latter, however, remain higher than under unconditional dispersal, thus undermining isolation by distance, and hindering speciation in sexual populations. Consequently, the speciation of sexual populations under conditional dispersal is triggered by a steeper gradient than under unconditional dispersal. Enhancing the disruptiveness of frequency-dependent selection, more box-shaped competition kernels dramatically lower the speciation-enabling slope of the environmental gradient. PMID:21194533

The evolution of conditional dispersal and reproductive isolation along environmental gradients.

PubMed

Payne, Joshua L; Mazzucco, Rupert; Dieckmann, Ulf

2011-03-21

Dispersal modulates gene flow throughout a population's spatial range. Gene flow affects adaptation at local spatial scales, and consequently impacts the evolution of reproductive isolation. A recent theoretical investigation has demonstrated that local adaptation along an environmental gradient, facilitated by the evolution of limited dispersal, can lead to parapatric speciation even in the absence of assortative mating. This and other studies assumed unconditional dispersal, so individuals start dispersing without regard to local environmental conditions. However, many species disperse conditionally; their propensity to disperse is contingent upon environmental cues, such as the degree of local crowding or the availability of suitable mates. Here, we use an individual-based model in continuous space to investigate by numerical simulation the relationship between the evolution of threshold-based conditional dispersal and parapatric speciation driven by frequency-dependent competition along environmental gradients. We find that, as with unconditional dispersal, parapatric speciation occurs under a broad range of conditions when reproduction is asexual, and under a more restricted range of conditions when reproduction is sexual. In both the asexual and sexual cases, the evolution of conditional dispersal is strongly influenced by the slope of the environmental gradient: shallow environmental gradients result in low dispersal thresholds and high dispersal distances, while steep environmental gradients result in high dispersal thresholds and low dispersal distances. The latter, however, remain higher than under unconditional dispersal, thus undermining isolation by distance, and hindering speciation in sexual populations. Consequently, the speciation of sexual populations under conditional dispersal is triggered by a steeper gradient than under unconditional dispersal. Enhancing the disruptiveness of frequency-dependent selection, more box-shaped competition kernels dramatically lower the speciation-enabling slope of the environmental gradient. Copyright © 2010 Elsevier Ltd. All rights reserved.

Reducing the gradient artefact in simultaneous EEG-fMRI by adjusting the subject's axial position.

PubMed

Mullinger, Karen J; Yan, Winston X; Bowtell, Richard

2011-02-01

Large artefacts that compromise EEG data quality are generated when electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) are carried out concurrently. The gradient artefact produced by the time-varying magnetic field gradients is the largest of these artefacts. Although average artefact correction (AAS) and related techniques can remove the majority of this artefact, the need to avoid amplifier saturation necessitates the use of a large dynamic range and strong low-pass filtering in EEG recording. Any intrinsic reduction in the gradient artefact amplitude would allow data with a higher bandwidth to be acquired without amplifier saturation, thus increasing the frequency range of neuronal activity that can be investigated using combined EEG-fMRI. Furthermore, gradient artefact correction methods assume a constant artefact morphology over time, so their performance is compromised by subject movement. Since the resulting, residual gradient artefacts can easily swamp signals from brain activity, any reduction in their amplitude would be highly advantageous for simultaneous EEG-fMRI studies. The aim of this work was to investigate whether adjustment of the subject's axial position in the MRI scanner can reduce the amplitude of the induced gradient artefact, before and after artefact correction using AAS. The variation in gradient artefact amplitude as a function of the subject's axial position was first investigated in six subjects by applying gradient pulses along the three Cartesian axes. The results of this study showed that a significant reduction in the gradient artefact magnitude can be achieved by shifting the subject axially by 4 cm towards the feet relative to the standard subject position (nasion at iso-centre). In a further study, the 4-cm shift was shown to produce a 40% reduction in the RMS amplitude (and a 31% reduction in the range) of the gradient artefact generated during the execution of a standard multi-slice, EPI sequence. By picking out signals occurring at harmonics of the slice acquisition frequency, it was also shown that the 4-cm shift led to a 36% reduction in the residual gradient artefact after AAS. Functional and anatomical MR data quality is not affected by the 4-cm shift, as the head remains in the homogeneous region of the static magnet field and gradients. Copyright © 2010 Elsevier Inc. All rights reserved.

Principal processes within the estuarine salinity gradient: a review.

PubMed

Telesh, Irena V; Khlebovich, Vladislav V

2010-01-01

The salinity gradient is one of the main features characteristic of any estuarine ecosystem. Within this gradient in a critical salinity range of 5-8 PSU the major biotic and abiotic processes demonstrate non-linear dynamics of change in rates and directions. In estuaries, this salinity range acts as both external ecological factor and physiological characteristics of internal environment of aquatic organisms; it divides living conditions appropriate for freshwater and marine faunas, separates invertebrate communities with different osmotic regulation types, and defines the distribution range of high taxa. In this paper, the non-linearity of biotic processes within the estuarine salinity gradient is illustrated by the data on zooplankton from the Baltic estuaries. The non-tidal Baltic Sea provides a good demonstration of the above phenomena due to gradual changes of environmental factors and relatively stable isohalines. The non-linearity concept coupled with the ecosystem approach served the basis for a new definition of an estuary proposed by the authors. Copyright 2010 Elsevier Ltd. All rights reserved.

Morphology, Molecular Genetics, and Bioacoustics Support Two New Sympatric Xenophrys Toads (Amphibia: Anura: Megophryidae) in Southeast China

PubMed Central

Wang, Yingyong; Zhao, Jian; Yang, Jianhuan; Zhou, Zhixin; Chen, Guoling; Liu, Yang

2014-01-01

Given their recent worldwide declines and extinctions, characterization of species-level diversity is of critical importance for large-scale biodiversity assessments and conservation of amphibians. This task is made difficult by the existence of cryptic species complexes, species groups comprising closely related and morphologically analogous species. The combination of morphology, genetic, and bioacoustic analyses permits robust and accurate species identification. Using these methods, we discovered two undescribed Xenophrys species, namely Xenophrys lini sp. nov. and Xenophrys cheni sp. nov. from the middle range of Luoxiao Mountains, southeast China. These two new species can be reliably distinguished from other known congeners by morphological and morphometric differences, distinctness in male advertisement calls, and substantial genetic distances (>3.6%) based on the mitochondrial 16s and 12s rRNA genes. The two new species, together with X. jinggangensis, are sympatric in the middle range of Luoxiao Mountains but may be isolated altitudinally and ecologically. Our study provides a first step to help resolve previously unrecognized cryptic biodiversity and provides insights into the understanding of Xenophrys diversification in the mountain complexes of southeast China. PMID:24714161

Addressing uncertainty in adaptation planning for agriculture.

PubMed

Vermeulen, Sonja J; Challinor, Andrew J; Thornton, Philip K; Campbell, Bruce M; Eriyagama, Nishadi; Vervoort, Joost M; Kinyangi, James; Jarvis, Andy; Läderach, Peter; Ramirez-Villegas, Julian; Nicklin, Kathryn J; Hawkins, Ed; Smith, Daniel R

2013-05-21

We present a framework for prioritizing adaptation approaches at a range of timeframes. The framework is illustrated by four case studies from developing countries, each with associated characterization of uncertainty. Two cases on near-term adaptation planning in Sri Lanka and on stakeholder scenario exercises in East Africa show how the relative utility of capacity vs. impact approaches to adaptation planning differ with level of uncertainty and associated lead time. An additional two cases demonstrate that it is possible to identify uncertainties that are relevant to decision making in specific timeframes and circumstances. The case on coffee in Latin America identifies altitudinal thresholds at which incremental vs. transformative adaptation pathways are robust options. The final case uses three crop-climate simulation studies to demonstrate how uncertainty can be characterized at different time horizons to discriminate where robust adaptation options are possible. We find that impact approaches, which use predictive models, are increasingly useful over longer lead times and at higher levels of greenhouse gas emissions. We also find that extreme events are important in determining predictability across a broad range of timescales. The results demonstrate the potential for robust knowledge and actions in the face of uncertainty.

Addressing uncertainty in adaptation planning for agriculture

PubMed Central

Vermeulen, Sonja J.; Challinor, Andrew J.; Thornton, Philip K.; Campbell, Bruce M.; Eriyagama, Nishadi; Vervoort, Joost M.; Kinyangi, James; Jarvis, Andy; Läderach, Peter; Ramirez-Villegas, Julian; Nicklin, Kathryn J.; Hawkins, Ed; Smith, Daniel R.

2013-01-01

We present a framework for prioritizing adaptation approaches at a range of timeframes. The framework is illustrated by four case studies from developing countries, each with associated characterization of uncertainty. Two cases on near-term adaptation planning in Sri Lanka and on stakeholder scenario exercises in East Africa show how the relative utility of capacity vs. impact approaches to adaptation planning differ with level of uncertainty and associated lead time. An additional two cases demonstrate that it is possible to identify uncertainties that are relevant to decision making in specific timeframes and circumstances. The case on coffee in Latin America identifies altitudinal thresholds at which incremental vs. transformative adaptation pathways are robust options. The final case uses three crop–climate simulation studies to demonstrate how uncertainty can be characterized at different time horizons to discriminate where robust adaptation options are possible. We find that impact approaches, which use predictive models, are increasingly useful over longer lead times and at higher levels of greenhouse gas emissions. We also find that extreme events are important in determining predictability across a broad range of timescales. The results demonstrate the potential for robust knowledge and actions in the face of uncertainty. PMID:23674681

Impacts of urbanization on surface sediment quality: evidence from polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) contaminations in the Grand Canal of China.

PubMed

Hong, Youwei; Yu, Shen; Yu, Guangbin; Liu, Yi; Li, Guilin; Wang, Min

2012-06-01

Organic pollutants, especially synthetic organic compounds, can indicate paces of anthropogenic activities. Effects of urbanization on polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) distributions in surface sediment were conducted in urban sections of the Grand Canal, China, consisting of a four-level urbanization gradient. The four-level urbanization gradients include three countryside towns, two small-size cities, three medium-size cities, and a large-size city. Diagnostic ratio analysis and factor analysis-multiple linear regression model were used for source apportionment of PAHs. Sediment quality guidelines (SQGs) of USA and Canada were employed to assess ecological risks of PAHs and PCBs in surface sediments of the Canal. Ranges of PAH and PCB concentrations in surface sediments were 0.66-22 mg/kg and 0.5-93 μg/kg, respectively. Coal-related sources were primary PAH sources and followed by vehicular emission. Total concentration, composition, and source apportionment of PAHs exhibited urbanization gradient effects. Total PCB concentrations increased with the urbanization gradient, while total PAHs concentration in surface sediments presented an inverted U Kuznets curve with the urbanization gradient. Elevated concentrations of both PAHs and PCBs ranged at effect range low levels or interim SQG, assessed by USA and Canadian SQGs. PAHs and PCBs in surface sediments of the Grand Canal showed urbanization gradient effects and low ecological risks.

Simulated projection of ISMR over Indian Himalayan region: assessment from CSIRO-CORDEX South Asia experiments

NASA Astrophysics Data System (ADS)

Mukherjee, Sandipan; Hazra, Anupam; Kumar, Kireet; Nandi, Shyamal K.; Dhyani, Pitamber P.

2017-09-01

In view of a significant lacuna in the Himalaya-specific knowledge of forthcoming expected changes in the rainfall climatology, this study attempts to assess the expected changes in the Indian summer monsoon rainfall (ISMR) pattern exclusively over the Indian Himalayan Region (IHR) during 2020-2070 in comparison to a baseline period of 1970-2005 under two different warming scenarios, i.e., representative concentration pathways 4.5 and 8.5 (RCP 4.5 and RCP 8.5). Five climate model products from the Commonwealth Scientific and Industrial Research Organization initiated Coordinated Regional Climate Downscaling Experiment of World Climate Research Programme over south Asia region are used for this purpose. Among the several different features of ISMR, this study attempts to investigate expected changes in the average summer monsoon rainfall and percent monthly rainfall to the total monsoon seasonal rainfall using multimodel averages. Furthermore, this study attempts to identify the topographical ranges which are expected to be mostly affected by the changing average monsoon seasonal rainfall over IHR. Results from the multimodel average analysis indicate that the rainfall climatology is expected to increase by >0.75 mm/day over the foothills of northwest Himalaya during 2020-2070, whereas the rainfall climatology is expected to decrease for the flood plains of Brahmaputra under a warmer climate. The monthly percent rainfall of June is expected to rise by more than 1% over the northwestern Himalaya during 2020-2040 (although insignificant at p value <0.05), whereas the same for August and September is expected to decrease over the eastern Himalaya under a warmer climate. In terms of rainfall changes along the altitudinal gradient, this study indicates that the two significant rainfall regions, one at around 900 m and the other around 2000 m of the northwestern Himalaya are expected to see positive changes (>1%) in rainfall climatology during 2020-2070, whereas regions more than 1500 m in eastern Himalaya are expected to experience inconsistent variation in rainfall climatology under a warmer climate scenario.

Taxonomic Revision of Hispaniola Tiger Beetles in the Genus Brasiella Rivalier 1954 (Coleoptera, Carabidae, Cicindelinae)

PubMed Central

Acciavatti, Robert E.

2011-01-01

Abstract The Brasiella tiger beetle fauna on Hispaniola, the second largest island of the Greater Antilles, has more species diversity than currently recognized as all populations previously have been assigned to the insular endemic Brasiella dominicana (Mandl). A comparative study of adult morphology, particularly male genitalic and female abdominal characters, for available Brasiella specimens from populations on Hispaniola, proposes eight additional new species also endemic to this island. Except for three sympatric species in the Sierra de Baoruco in southern Dominican Republic occurring in different habitats, all the Brasiella on Hispaniola appear to be allopatric. Most species occur in the major mountainous regions of Hispaniola. Two species, however, are known only from river floodplains in the southern coastal plain of the Dominican Republic. Brasiella dominicana (Mandl) and Brasiella ocoa, new species, occur along river floodplains emanating from the eastern end of the Cordillera Central in the Dominican Republic. Two new Brasiella species, Brasiella bellorum, and Brasiella philipi, occur in the Cordillera Central, Dominican Republic, the former species from central portions, and the latter species from north slopes of this mountain range, respectively. Three new Brasiella species, Brasiella rawlinsi, Brasiella iviei, and Brasiella youngi, are isolated in the Sierra de Baoruco, Dominican Republic, where each occupies a different habitat along an altitudinal gradient. The two new Brasiella species in Haiti are Brasiella darlingtoniana, in the Massif de la Selle, and Brasiella davidsoni, in the Massif de la Hotte. All nine Brasiella species on Hispaniola, along with Brasiella viridicollis (Dejean) and its two subspecies on Cuba, belong to the viridicollis species group of the genus Brasiella based on criteria presented in earlier published phylogenetic studies of Brazilian and West Indian tiger beetles. The subspecies Brasiella viridicollis fernandozayasi (Kippenhan, Ivie and Hopp) may represent a distinct species within this species group, whereas removal of Brasiella wickhami (W. Horn) from this species group seems warranted based on evidence presented. A general overview of species relationships for the Brasiella on Hispaniola are discussed, along with the current and ancestral geographic distributions of the Brasiella viridicollis species group in the West Indies. PMID:22371664

Slow life histories in lizards living in the highlands of the Andes Mountains.

PubMed

Boretto, Jorgelina M; Cabezas-Cartes, Facundo; Ibargüengoytía, Nora R

2018-05-01

In the highlands of the Andes, lizards must balance precisely the allocation of energy for growth and reproduction to ensure their survival. We studied the individuals' age, growth rates, age at sexual maturity, and maximum life span of the viviparous lizard Phymaturus antofagastensis, endemic of cold and harsh environments at high altitudes in the Andes Mountains of Catamarca province, Argentina. We also estimated key life history parameters like reproductive effort, lifetime reproductive effort, net reproductive rate, and relative reproductive time in P. antofagastensis as well as in other Phymaturus to compare the interplay among growth, maintenance, and reproduction in species that live across a latitudinal and altitudinal gradient. We found that females and males of P. antofagastensis mature late in life, at 6-7 years old, respectively, and some individuals reached 20 years of age. Adult females showed higher specific growth rates than males and an adult life span of 9 years which, due to their biennial reproduction, results in an estimated production of only four litters in life. This species exhibits one of the highest lifetime reproductive efforts described for lizards. Our results indicate the existence of a tradeoff between the number of reproductive events throughout life and reproductive effort devoted to each event in Phymaturus, related to the phylogenetic group. The palluma group shows low reproductive effort but high number of reproductive events throughout their lives, whereas the patagonicus group shows high reproductive efforts in low number of reproductive events.

Temperature and population density determine reservoir regions of seasonal persistence in highland malaria.

PubMed

Siraj, Amir S; Bouma, Menno J; Santos-Vega, Mauricio; Yeshiwondim, Asnakew K; Rothman, Dale S; Yadeta, Damtew; Sutton, Paul C; Pascual, Mercedes

2015-12-07

A better understanding of malaria persistence in highly seasonal environments such as highlands and desert fringes requires identifying the factors behind the spatial reservoir of the pathogen in the low season. In these 'unstable' malaria regions, such reservoirs play a critical role by allowing persistence during the low transmission season and therefore, between seasonal outbreaks. In the highlands of East Africa, the most populated epidemic regions in Africa, temperature is expected to be intimately connected to where in space the disease is able to persist because of pronounced altitudinal gradients. Here, we explore other environmental and demographic factors that may contribute to malaria's highland reservoir. We use an extensive spatio-temporal dataset of confirmed monthly Plasmodium falciparum cases from 1995 to 2005 that finely resolves space in an Ethiopian highland. With a Bayesian approach for parameter estimation and a generalized linear mixed model that includes a spatially structured random effect, we demonstrate that population density is important to disease persistence during the low transmission season. This population effect is not accounted for in typical models for the transmission dynamics of the disease, but is consistent in part with a more complex functional form of the force of infection proposed by theory for vector-borne infections, only during the low season as we discuss. As malaria risk usually decreases in more urban environments with increased human densities, the opposite counterintuitive finding identifies novel control targets during the low transmission season in African highlands. © 2015 The Author(s).

Temperature and population density determine reservoir regions of seasonal persistence in highland malaria

PubMed Central

Siraj, Amir S.; Bouma, Menno J.; Santos-Vega, Mauricio; Yeshiwondim, Asnakew K.; Rothman, Dale S.; Yadeta, Damtew; Sutton, Paul C.; Pascual, Mercedes

2015-01-01

A better understanding of malaria persistence in highly seasonal environments such as highlands and desert fringes requires identifying the factors behind the spatial reservoir of the pathogen in the low season. In these ‘unstable’ malaria regions, such reservoirs play a critical role by allowing persistence during the low transmission season and therefore, between seasonal outbreaks. In the highlands of East Africa, the most populated epidemic regions in Africa, temperature is expected to be intimately connected to where in space the disease is able to persist because of pronounced altitudinal gradients. Here, we explore other environmental and demographic factors that may contribute to malaria's highland reservoir. We use an extensive spatio-temporal dataset of confirmed monthly Plasmodium falciparum cases from 1995 to 2005 that finely resolves space in an Ethiopian highland. With a Bayesian approach for parameter estimation and a generalized linear mixed model that includes a spatially structured random effect, we demonstrate that population density is important to disease persistence during the low transmission season. This population effect is not accounted for in typical models for the transmission dynamics of the disease, but is consistent in part with a more complex functional form of the force of infection proposed by theory for vector-borne infections, only during the low season as we discuss. As malaria risk usually decreases in more urban environments with increased human densities, the opposite counterintuitive finding identifies novel control targets during the low transmission season in African highlands. PMID:26631558

Numerical modeling of the destruction of steel plates with a gradient substrate

NASA Astrophysics Data System (ADS)

Orlov, M. Yu.; Glazyrin, V. P.; Orlov, Yu. N.

2017-10-01

The paper presents the results of numerical simulation of the shock loading process of steel barriers with a gradient substrate. In an elastic plastic axisymmetric statement, a shock is simulated along the normal in the range of initial velocities up to 300 m / s. A range of initial velocities was revealed, in which the presence of a substrate "saved" the obstacle from spallation. New tasks were announced to deepen scientific knowledge about the behavior of unidirectional gradient barriers at impact. The results of calculations are obtained in the form of graphs, calculated configurations of the "impact - barrier" and tables.

Ray tracing evaluation of a technique for correcting the refraction errors in satellite tracking data

NASA Technical Reports Server (NTRS)

Gardner, C. S.; Rowlett, J. R.; Hendrickson, B. E.

1978-01-01

Errors may be introduced in satellite laser ranging data by atmospheric refractivity. Ray tracing data have indicated that horizontal refractivity gradients may introduce nearly 3-cm rms error when satellites are near 10-degree elevation. A correction formula to compensate for the horizontal gradients has been developed. Its accuracy is evaluated by comparing it to refractivity profiles. It is found that if both spherical and gradient correction formulas are employed in conjunction with meteorological measurements, a range resolution of one cm or less is feasible for satellite elevation angles above 10 degrees.

Fluvial signatures of modern and paleo orographic rainfall gradients

NASA Astrophysics Data System (ADS)

Schildgen, Taylor; Strecker, Manfred

2016-04-01

The morphology of river profiles is intimately linked to both climate and tectonic forcing. While much interest recently has focused on how river profiles can be inverted to derive uplift histories, here we show how in regions of strong orographic rainfall gradients, rivers may primarily record spatial patterns of precipitation. As a case study, we examine the eastern margin of the Andean plateau in NW Argentina, where the outward (eastward) growth of a broken foreland has led to a eastward shift in the main orographic rainfall gradient over the last several million years. Rivers influenced by the modern rainfall gradient are characterized by normalized river steepness values in tributary valleys that closely track spatial variations in rainfall, with higher steepness values in drier areas and lower steepness values in wetter areas. The same river steepness pattern has been predicted in landscape evolution models that apply a spatial gradient in rainfall to a region of uniform erosivity and uplift rate (e.g., Han et al., 2015). Also, chi plots from river networks on individual ranges affected by the modern orographic rainfall reveal patterns consistent with assymmetric precipitation across the range: the largest channels on the windward slopes are characterized by capture, while the longest channels on the leeward slopes are dominated by beheadings. Because basins on the windward side both lengthen and widen, tributary channels in the lengthening basins are characterized by capture, while tributary channels from neighboring basins on the windward side are dominated by beheadings. These patterns from the rivers influenced by the modern orographic rainfall gradient provide a guide for identifying river morphometric signatures of paleo orographic rainfall gradients. Mountain ranges to the west of the modern orographic rainfall have been interpreted to mark the location of orographic rainfall in the past, but these ranges are now in spatially near-uniform semi-arid to arid precipitation regimes. Indeed, despite uniform lithology and uplift history, we see patterns in river steepness values and in chi plots that are consistest a rainfall gradient on the (former) windward side of the range and asymmetric precipitation across the range. We suggest that morphological aspects of the river networks in such regions are dominated by their history of changing climate. These morphologic signatures appear to persist for millions of years in NW Argentina, most likely because the transition from a wetter to a drier climate has prevented a rapid readjustment to new forcing conditions. Reference: Han, J., Gasparini, N.M., and Johnson, J.P., 2015, Measuring the imprint of orographic rainfall gradients on the morphology of steady-state numerical fluvial landscapes. Earth Surf. Process. Landforms, 40(10), 1334-1350.

Signatures of local adaptation along environmental gradients in a range-expanding damselfly (Ischnura elegans).

PubMed

Dudaniec, Rachael Y; Yong, Chuan Ji; Lancaster, Lesley T; Svensson, Erik I; Hansson, Bengt

2018-06-01

Insect distributions are shifting rapidly in response to climate change and are undergoing rapid evolutionary change. We investigate the molecular signatures underlying local adaptation in the range-expanding damselfly, Ischnura elegans. Using a landscape genomic approach combined with generalized dissimilarity modelling (GDM), we detect selection signatures on loci via allelic frequency change along environmental gradients. We analyse 13,612 single nucleotide polymorphisms (SNPs), derived from restriction site-associated DNA sequencing (RADseq), in 426 individuals from 25 sites spanning the I. elegans distribution in Sweden, including its expanding northern range edge. Environmental association analysis (EAA) and the magnitude of allele frequency change along the range expansion gradient revealed significant signatures of selection in relation to high maximum summer temperature, high mean annual precipitation and low wind speeds at the range edge. SNP annotations with significant signatures of selection revealed gene functions associated with ongoing range expansion, including heat shock proteins (HSP40 and HSP70), ion transport (V-ATPase) and visual processes (long-wavelength-sensitive opsin), which have implications for thermal stress response, salinity tolerance and mate discrimination, respectively. We also identified environmental thresholds where climate-mediated selection is likely to be strong, and indicate that I. elegans is rapidly adapting to the climatic environment during its ongoing range expansion. Our findings empirically validate an integrative approach for detecting spatially explicit signatures of local adaptation along environmental gradients. © 2018 John Wiley & Sons Ltd.

Elevational Gradient in Species Richness Pattern of Epigaeic Beetles and Underlying Mechanisms at East Slope of Balang Mountain in Southwestern China

PubMed Central

Yu, Xiao-Dong; Lü, Liang; Luo, Tian-Hong; Zhou, Hong-Zhang

2013-01-01

We report on the species richness patterns of epigaeic beetles (Coleoptera: Carabidae and Staphylinidae) along a subtropical elevational gradient of Balang Mountain, southwestern China. We tested the roles of environmental factors (e.g. temperature, area and litter cover) and direct biotic interactions (e.g. foods and antagonists) that shape elevational diversity gradients. Beetles were sampled at 19 sites using pitfall traps along the studied elevational gradient ranging from 1500 m–4000 m during the 2004 growing season. A total of 74416 specimens representing 260 species were recorded. Species richness of epigaeic beetles and two families showed unimodal patterns along the elevational gradient, peaking at mid-elevations (c. 2535 m), and the ranges of most beetle species were narrow along the gradient. The potential correlates of both species richness and environmental variables were examined using linear and second order polynomial regressions. The results showed that temperature, area and litter cover had strong explanatory power of beetle species richness for nearly all richness patterns, of beetles as a whole and of Carabidae and Staphylinidae, but the density of antagonists was associated with species richness of Carabidae only. Multiple regression analyses suggested that the three environmental factors combined contributed most to richness patterns for most taxa. The results suggest that environmental factors associated with temperature, area and habitat heterogeneity could account for most variation in richness pattern of epigaeic beetles. Additionally, the mid-elevation peaks and the small range size of most species indicate that conservation efforts should give attention to the entire gradient rather than just mid-elevations. PMID:23874906

The effect of shear flow and the density gradient on the Weibel instability growth rate in the dense plasma

NASA Astrophysics Data System (ADS)

Amininasab, S.; Sadighi-Bonabi, R.; Khodadadi Azadboni, F.

2018-02-01

Shear stress effect has been often neglected in calculation of the Weibel instability growth rate in laser-plasma interactions. In the present work, the role of the shear stress in the Weibel instability growth rate in the dense plasma with density gradient is explored. By increasing the density gradient, the shear stress threshold is increasing and the range of the propagation angles of growing modes is limited. Therefore, by increasing steps of the density gradient plasma near the relativistic electron beam-emitting region, the Weibel instability occurs at a higher stress flow. Calculations show that the minimum value of the stress rate threshold for linear polarization is greater than that of circular polarization. The Wiebel instability growth rate for linear polarization is 18.3 times circular polarization. One sees that for increasing stress and density gradient effects, there are smaller maximal growth rates for the range of the propagation angles of growing modes /π 2 < θ m i n < π and /3 π 2 < θ m i n < 2 π in circular polarized plasma and for /k c ω p < 4 in linear polarized plasma. Therefore, the shear stress and density gradient tend to stabilize the Weibel instability for /k c ω p < 4 in linear polarized plasma. Also, the shear stress and density gradient tend to stabilize the Weibel instability for the range of the propagation angles of growing modes /π 2 < θ m i n < π and /3 π 2 < θ m i n < 2 π in circular polarized plasma.

Altitudinal variation in growth, bud break and susceptibility to balsam twig aphid damage of balsam fir from 6 Vermont seed sources

Treesearch

Ronald C. Wilkinson; Paul G. Schaberg

1992-01-01

Differences in 10-year heights, 4-year growth from 1987 through 1990, relative timing of budbreak and damage by the balsam twig aphid (Mindarus abietinus Koch.) among balsam fir (Abies balsamea (L.) Mill.) from 6 Vermont seed sources originating from different elevations were examined. Height differences among seed sources were...

Holocene vegetation and fire history of the Coast Range, western Oregon, USA

Treesearch

Colin J. Long; Cathy Whitlock; Patrick J. Bartlein

2007-01-01

Pollen and high-resolution charcoal records from three lakes were examined to reconstruct the vegetation and fire history of the Oregon Coast Range for the last 9000 years. The sites are located along a north to- south effective precipitation gradient and changes in vegetation and fire activity provided information on the nature of this gradient in the past. The...

Implementing quantum logic gates with gradient ascent pulse engineering: principles and practicalities.

PubMed

Rowland, Benjamin; Jones, Jonathan A

2012-10-13

We briefly describe the use of gradient ascent pulse engineering (GRAPE) pulses to implement quantum logic gates in nuclear magnetic resonance quantum computers, and discuss a range of simple extensions to the core technique. We then consider a range of difficulties that can arise in practical implementations of GRAPE sequences, reflecting non-idealities in the experimental systems used.

Protein gradient films of fibroin and gelatine.

PubMed

Claussen, Kai U; Lintz, Eileen S; Giesa, Reiner; Schmidt, Hans-Werner; Scheibel, Thomas

2013-10-01

Gradients are a natural design principle in biological systems that are used to diminish stress concentration where materials of differing mechanical properties connect. An interesting example of a natural gradient material is byssus, which anchors mussels to rocks and other hard substrata. Building upon previous work with synthetic polymers and inspired by byssal threads, protein gradient films are cast using glycerine-plasticized gelatine and fibroin exhibiting a highly reproducible and smooth mechanical gradient, which encompasses a large range of modulus from 160 to 550 MPa. The reproducible production of biocompatible gradient films represents a first step towards medical applications. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A comparative assessment of the biological properties of soils in the cultural and native cenoses of the Central Caucasus (using the example of the Terskii variant of altitudinal zonality in Kabardino-Balkaria)

NASA Astrophysics Data System (ADS)

Gorobtsova, O. N.; Gedgafova, F. V.; Uligova, T. S.; Tembotov, R. Kh.

2016-01-01

The biological properties of the most widespread automorphic and hydromorphic soils of cultural and native cenoses in the Terskii variant of the altitudinal zonality (Kabardino-Balkaria) are compared. The data on the humus reserves in the 0- to 20-cm soil layer and those on the carbon content in the microbial biomass calculated on the basis of the results of substrate-induced respiration measurements are presented. The share of carbon in the microbial biomass of the total organic carbon in the soils was determined. Long-term (more than 70 years) farming on the studied soils significantly changed their biological properties. The humus content and its reserves became lower by 25-40%. The physiological activity of the microbial biomass in the cultural soils decreased by more than 60%. Presently, the soils of the cultural cenoses function as an entire natural system, but at a lower level of fertility; the loss of more than 30% of the bioorganic potential (the critical threshold of soil system stability) indicates the disturbance of soil ecological functions, their stability, and the capability of self-restoration.

Altitudinal and chiral signature of persistent organochlorine pesticides in air, soil, and spruce needles (Picea abies) of the Alps.

PubMed

Shen, Heqing; Henkelmann, Bernhard; Levy, Walkiria; Zsolnay, Adam; Weiss, Peter; Jakobi, Gert; Kirchner, Manfred; Moche, Wolfgang; Braun, Katharina; Schramm, Karl-Werner

2009-04-01

The present study investigated the distribution, transportation, and biodegradation of the selected chiral persistent organochlorine pesticides (OCP) in the Alps. In the complex environment, we found the movement and fate of OCP could be defined by many factors. Taking HCE as an example, below the timberline its accumulation from air into SPMD increased with altitude and seasonally changed, but the trends reversed above the timberline. In soil, the tendency of HCE concentrations vs organic materials followed a sigmoid curve, and HCE concentration-altitude correlations are positive in central Alps but negative in southern Alps. The HCE enantiomeric ratios (ERs) in soil correlated to HCE isomers concentrations, the humus pH values, and the sampling site altitudes. HCE shift from humus to mineral soil can also be traced by ERs. The altitudinal and longitudinal trends in needles suggested that alpha-HCH has a more complex movementthan HCE in Alps. In conclusion, altitude conducted condensation, plant canopies, organic material in soil, and geographic specific precipitations may affect OCP distributions and transportation, whereas altitude conducted temperature and soil pH could dictate their fate in the environment.

Strong Altitudinal Control on Local Glacier's Response to Holocene Climate Change in Southwest Greenland

NASA Astrophysics Data System (ADS)

Larsen, N. K.; Levy, L.; Strunk, A.; Bjork, A. A.; Olsen, J.; Jeppesen, E.; Lauridsen, T.; Davidson, T. A.

2017-12-01

The sensitivity of glaciers and ice caps (GICs) in Greenland to prolonged warm periods is poorly constrained and geological records documenting the long-term glacial history are needed to put recent observations into a broader perspective. Here we report the results from three proglacial lakes where fluctuations in local glaciers located at different altitudes in Kobbefjord, southwest Greenland have been recorded. Our results show that the lakes received meltwater from the initial deglaciation of the area 9.2 cal. ka BP until 8.7-7.9 cal. ka BP when the meltwater input ceased as the glaciers most likely disappeared. Regrowth of glaciers began again at 5.5 cal. ka BP at 1,370 m a.s.l., 3.6 cal. ka at 1,170 m a.s.l., and 1.6 cal. ka BP at 1,000 m a.s.l., clearly reflecting strong altitudinal control of the GIC response to Neoglacial cooling. Our results highlight that GICs in Kobbefjord, southwest Greenland are primarily influenced by changes in summer air temperatures and winter precipitation and that they are facing a rapid decay that most likely will result in their disappearance within the next centuries as a consequence of global warming.

Assessing the accuracy of using oscillating gradient spin echo sequences with AxCaliber to infer micron-sized axon diameters.

PubMed

Mercredi, Morgan; Vincent, Trevor J; Bidinosti, Christopher P; Martin, Melanie

2017-02-01

Current magnetic resonance imaging (MRI) axon diameter measurements rely on the pulsed gradient spin-echo sequence, which is unable to provide diffusion times short enough to measure small axon diameters. This study combines the AxCaliber axon diameter fitting method with data generated from Monte Carlo simulations of oscillating gradient spin-echo sequences (OGSE) to infer micron-sized axon diameters, in order to determine the feasibility of using MRI to infer smaller axon diameters in brain tissue. Monte Carlo computer simulation data were synthesized from tissue geometries of cylinders of different diameters using a range of gradient frequencies in the cosine OGSE sequence . Data were fitted to the AxCaliber method modified to allow the new pulse sequence. Intra- and extra-axonal water were studied separately and together. The simulations revealed the extra-axonal model to be problematic. Rather than change the model, we found that restricting the range of gradient frequencies such that the measured apparent diffusion coefficient was constant over that range resulted in more accurate fitted diameters. Thus a careful selection of frequency ranges is needed for the AxCaliber method to correctly model extra-axonal water, or adaptations to the method are needed. This restriction helped reduce the necessary gradient strengths for measurements that could be performed with parameters feasible for a Bruker BG6 gradient set. For these experiments, the simulations inferred diameters as small as 0.5 μm on square-packed and randomly packed cylinders. The accuracy of the inferred diameters was found to be dependent on the signal-to-noise ratio (SNR), with smaller diameters more affected by noise, although all diameter distributions were distinguishable from one another for all SNRs tested. The results of this study indicate the feasibility of using MRI with OGSE on preclinical scanners to infer small axon diameters.

Colloidal attraction induced by a temperature gradient.

PubMed

Di Leonardo, R; Ianni, F; Ruocco, G

2009-04-21

Colloidal crystals are of extreme importance for applied research and for fundamental studies in statistical mechanics. Long-range attractive interactions, such as capillary forces, can drive the spontaneous assembly of such mesoscopic ordered structures. However, long-range attractive forces are very rare in the colloidal realm. Here we report a novel strong, long-ranged attraction induced by a thermal gradient in the presence of a wall. By switching the thermal gradient on and off, we can rapidly and reversibly form stable hexagonal 2D crystals. We show that the observed attraction is hydrodynamic in nature and arises from thermally induced slip flow on particle surfaces. We used optical tweezers to measure the force law directly and compare it to an analytical prediction based on Stokes flow driven by Marangoni-like forces.

The composite TTG series: evidence for a non-unique tectonic setting for Archaean crustal growth.

NASA Astrophysics Data System (ADS)

Moyen, Jean-François

2010-05-01

The geodynamic context of formation of the Archaean TTG (tonalite-trondhjemite-granodiorite) series, the dominant component of the Archaean continental crust, is a matter of debate. The two end-member models for TTG formation are melting of the basaltic slab in a "hot subduction"; and intra-plate melting of basaltic rocks at the base of thick crust (oceanic plateau?). Both models do however predict strikingly different geothermal gradients, as in the modern Earth a typical subduction gradient is less than 10 °C/km compared to > 25-30 °C/km in the case of plateau melting. Using a large database of published TTG compositions, and filtering it to remove rocks that do not match the definition of TTG, it is possible to show that the TTG series is actually composite and made of a range of geochemically identifiable components that can be referred to as low-, medium- and high-pressure groups. The geochemistry of the low-pressure group (low Al, Na, Sr, relatively high Y and Nb) is consistent with derivation from a plagioclase and garnet- amphibolite; the medium-pressure group was formed in equilibrium with a garnet-rich, plagioclase-poor amphibolite, whereas the high pressure group derived from a rutile bearing eclogite. As the temperature of melting of metamafic rocks is largely independent from pressure, this corresponds to melting along a range of contrasting geothermal gradients. The low pressure group requires gradients of 10-12 °C/km, whereas the gradient required for the low pressure group can be as high as 25—30 °C/km. Regardless of the preferred tectonic model for the Archaean, such a range of gradients requires an equally large range of tectonic sites for the formation of the Archaean continental crust.

Establishing Functional Relationships between Abiotic Environment, Macrophyte Coverage, Resource Gradients and the Distribution of Mytilus trossulus in a Brackish Non-Tidal Environment.

PubMed

Kotta, Jonne; Oganjan, Katarina; Lauringson, Velda; Pärnoja, Merli; Kaasik, Ants; Rohtla, Liisa; Kotta, Ilmar; Orav-Kotta, Helen

2015-01-01

Benthic suspension feeding mussels are an important functional guild in coastal and estuarine ecosystems. To date we lack information on how various environmental gradients and biotic interactions separately and interactively shape the distribution patterns of mussels in non-tidal environments. Opposing to tidal environments, mussels inhabit solely subtidal zone in non-tidal waterbodies and, thereby, driving factors for mussel populations are expected to differ from the tidal areas. In the present study, we used the boosted regression tree modelling (BRT), an ensemble method for statistical techniques and machine learning, in order to explain the distribution and biomass of the suspension feeding mussel Mytilus trossulus in the non-tidal Baltic Sea. BRT models suggested that (1) distribution patterns of M. trossulus are largely driven by separate effects of direct environmental gradients and partly by interactive effects of resource gradients with direct environmental gradients. (2) Within its suitable habitat range, however, resource gradients had an important role in shaping the biomass distribution of M. trossulus. (3) Contrary to tidal areas, mussels were not competitively superior over macrophytes with patterns indicating either facilitative interactions between mussels and macrophytes or co-variance due to common stressor. To conclude, direct environmental gradients seem to define the distribution pattern of M. trossulus, and within the favourable distribution range, resource gradients in interaction with direct environmental gradients are expected to set the biomass level of mussels.

Establishing Functional Relationships between Abiotic Environment, Macrophyte Coverage, Resource Gradients and the Distribution of Mytilus trossulus in a Brackish Non-Tidal Environment

PubMed Central

Kotta, Jonne; Oganjan, Katarina; Lauringson, Velda; Pärnoja, Merli; Kaasik, Ants; Rohtla, Liisa; Kotta, Ilmar; Orav-Kotta, Helen

2015-01-01

Benthic suspension feeding mussels are an important functional guild in coastal and estuarine ecosystems. To date we lack information on how various environmental gradients and biotic interactions separately and interactively shape the distribution patterns of mussels in non-tidal environments. Opposing to tidal environments, mussels inhabit solely subtidal zone in non-tidal waterbodies and, thereby, driving factors for mussel populations are expected to differ from the tidal areas. In the present study, we used the boosted regression tree modelling (BRT), an ensemble method for statistical techniques and machine learning, in order to explain the distribution and biomass of the suspension feeding mussel Mytilus trossulus in the non-tidal Baltic Sea. BRT models suggested that (1) distribution patterns of M. trossulus are largely driven by separate effects of direct environmental gradients and partly by interactive effects of resource gradients with direct environmental gradients. (2) Within its suitable habitat range, however, resource gradients had an important role in shaping the biomass distribution of M. trossulus. (3) Contrary to tidal areas, mussels were not competitively superior over macrophytes with patterns indicating either facilitative interactions between mussels and macrophytes or co-variance due to common stressor. To conclude, direct environmental gradients seem to define the distribution pattern of M. trossulus, and within the favourable distribution range, resource gradients in interaction with direct environmental gradients are expected to set the biomass level of mussels. PMID:26317668

High-elevation amplification of warming since the Last Glacial Maximum in East Africa: New perspectives from biomarker paleotemperature reconstructions

NASA Astrophysics Data System (ADS)

Loomis, S. E.; Russell, J. M.; Kelly, M. A.; Eggermont, H.; Verschuren, D.

2013-12-01

Tropical lapse rate variability on glacial/interglacial time scales has been hotly debated since the publication of CLIMAP in 1976. Low-elevation paleotemperature reconstructions from the tropics have repeatedly shown less warming from the Last Glacial Maximum (LGM) to present than reconstructions from high elevations, leading to widespread difficulty in estimating the true LGM-present temperature change in the tropics. This debate is further complicated by the fact that most paleotemperature estimates from high elevations in the tropics are derived from pollen- and moraine-based reconstructions of altitudinal shifts in vegetation belts and glacial equilibrium line altitudes (ELAs). These traditional approaches rely on the assumption that lapse rates have remained constant through time. However, this assumption is problematic in the case of the LGM, when pervasive tropical aridity most likely led to substantial changes in lapse rates. Glycerol dialkyl glycerol tetraethers (GDGTs) can be used to reconstruct paleotemperatures independent of hydrological changes, making them the ideal proxy to reconstruct high elevation temperature change and assess lapse rate variability through time. Here we present two new equatorial paleotemperature records from high elevations in East Africa (Lake Rutundu, Mt. Kenya and Lake Mahoma, Rwenzori Mountains, Uganda) based on branched GDGTs. Our record from Lake Rutundu shows deglacial warming starting near 17 ka and a mid-Holocene thermal maximum near 5 ka. The overall amplitude of warming in the Lake Rutundu record is 6.8×1.0°C from the LGM to the present, with mid-Holocene temperatures 1.6×0.9°C warmer than modern. Our record from Lake Mahoma extends back to 7 ka and shows similar temperature trends to our record from Lake Rutundu, indicating similar temporal resolution of high-elevation temperature change throughout the region. Combining these new records with three previously published GDGT temperature records from different elevations in East Africa (Sacred Lake, Lake Tanganyika, and Lake Malawi), we are able to reconstruct a continuous record of lapse rates and freezing level heights (FLHs) back to the LGM. We find that tropical lapse rates have varied widely over the last 22 ky, with the largest (lowest) lapse rate (FLH) around the LGM, while the smallest (highest) lapse rate (FLH) occurs during the mid-Holocene, confirming the amplification of warming at high altitudes between the LGM and present. These lapse rate and FLH reconstructions match records of regional hydrological variability, confirming the importance of glacial/interglacial humidity variations on altitudinal temperature gradients in the tropics. Furthermore, the FLH record largely matches records of tropical glacier ELA changes, indicating that warming from LGM-present was likely amplified at high altitudes throughout the tropics.

Hydrogen isotope ratios of terrestrial leaf wax n-alkanes from the Tibetan Plateau: Controls on apparent enrichment factors, effect of vapor sources and implication for altimetry

NASA Astrophysics Data System (ADS)

Zhang, Xiaolong; Xu, Baiqing; Günther, Franziska; Mügler, Ines; Lange, Markus; Zhao, Huabiao; Li, Jiule; Gleixner, Gerd

2017-08-01

Empirical evidence suggested that the altitudinal dependence of hydrogen isotope ratios of leaf wax n-alkanes (δDwax) can be used to estimate paleoaltitudinal changes. However, the application of δDwax-based paleoaltimetry remains difficult, as the impacts of evaporative, transpirative and biosynthetic processes on hydrogen isotope fractionations in changing environments and the influence of likely changing water vapor sources are not well explored. For this study, we sampled stream waters, soils and plant leaves along two transects spanning large gradients of altitude, precipitation amount, vapor source, temperature and vegetation type on the Tibetan Plateau (TP). δD values of stream water (as an approximation for δDp), soil water (δDsw) and plant leaf water (δDlw) as well as leaf wax n-alkanes were measured in order to quantify isotopic fractionations in the formation of leaf waxes. Most interestingly, we found a strong negative correlation between the evapotranspirative enrichment of leaf water against precipitation (εlw-p), which combines the effects of soil evaporation and leaf transpiration, and the biosynthetic hydrogen isotope fractionation (εwax-lw), which describes isotopic enrichment between leaf wax and leaf water. The relationship yields a steady apparent isotopic enrichment factor (εwax-p) between leaf wax and precipitation, which is independent from climatic parameters and has an average value of -107 ± 26‰ for grasses (monocotyledons) and -77 ± 22‰ for trees (dicotyledons). Since the terrestrial n-alkanes, especially n-C27 and n-C29, in sediments are derived from trees and grasses, the likely change of the vegetation type in the uplift of mountains can change the isotopic estimates by about ±30‰, which corresponds to an altitudinal change of ∼1600 m. We, therefore, suggest that hydrogen isotope ratio of sedimentary n-C31 alkane, which is mainly derived from grasses might be better proxies to reconstruct paleoaltitudes. Our large dataset of δDwax from trees and grasses that aimed to mirror the variability of environmental factors over geological time frames showed the lapse rates were significant, but much smaller than in previous studies. Most importantly our result demonstrated that the lapse rate significantly differed for both transects (p = 0.0068), i.e. 0.87 ± 0.71‰/100 m (R2 = 0.28, p = 0.2841, n = 6) and 2.28 ± 0.82‰/100 m (R2 = 0.34, p = 0.0135, n = 17) for Indian monsoon and Westerly dominated areas, respectively. This suggests that different moisture sources might strongly affected the observed lapse rates. In consequences altitude reconstructions are strongly complicated in areas with likely changing air masses like the Tibetan Plateau.

Early Pliocene vegetation distribution in Europe

NASA Astrophysics Data System (ADS)

Popescu, S.; Warny, S.; Suc, J.

2010-12-01

The Early Pliocene corresponds to a global warm climate documented by marine & terrestrial records. Reconstruction of climatic parameters, based on terrestrial proxies, indicate at European mid-latitudes a MAT higher of about 1-5°C than today and MAP higher of about 400-1000 mm. This global warm situation was interrupted between 4.7 - 4.5 Ma by a cooling event related to small fluctuations of the Antarctic ice-sheet that modify the floristic assemblages. according to pollen recors, the Northern Mediterranean area is characterized by dominance of arboreal pollen, suggesting a dense forest cover, on contrary to the Southern Mediterranean where herbs were prevalent, signifying a widespread development of open vegetation during the early Pliocene. Such a contrast in landscape between the North and the South of the Mediterranean is to be related to the latitudinal gradient in humidity. In the North Mediterranean area, the vegetation organization was also closely linked to the relief. Coastal plains were inhabited by Taxodiaceae swamps replaced in some places by marshes. With respect to the geographic position, several plant ecosystems can distinguished: (1) salt marshes, along the Atlantic coastline (zone A); (2) marshes mostly made of Cyperaceae evidenced on the Mediterranean coastline. Such juxtaposed assemblages resemble the modern vegetation of the Mississippi Delta and Florida. Peculiar vegetation assemblages characterize the Mediterranean coastal plains. In the southeastern Mediterranean region (Zone B), the open vegetation was composed by herbs including subdesertic elements. Mediterranean xerophytes are only numerically represented in the area of Tarragona and Sicily, their assemblage resemble the modern thermo-mediterranean formation. Close to the mountains (Zone C) vegetation is organized according to an altitudinal gradient. The low altitude vegetation was composed by Taxodiaceae (Sequoia) while Cathaya and Cedrus dominated the mid-altitude belt. Abies and Picea developed in higher altitude. The Eastern Europe vegetation (zone D) was characterized by coexistent warm-temperate forests and open ecosystems. Some megathermic and mega-mesothermic elements were persisting. Mediterranean xerophytes were indentified in few amounts in the Eastern Europe, showing a slight increase according to the latitudinal gradient. Site 380A (Black Sea) provides relatively high percentages of Artemisia growing in Anatolia, which increased again during the cooler periods. Anatolia probably represents the origin of the repeated steppe expansions which occurred in Europe at each glacial phase. Finally, the Nile region (zone E) documents the presence of savannah (composed mainly by Poaceae and Cyperaceae) including some subdesertic taxa. Nile riparian forests preserved several tropical-subtropical elements.

Tectonic uplift, threshold hillslopes, and denudation rates in a developing mountain range

USGS Publications Warehouse

Binnie, S.A.; Phillips, W.M.; Summerfield, M.A.; Fifield, L.K.

2007-01-01

Studies across a broad range of drainage basins have established a positive correlation between mean slope gradient and denudation rates. It has been suggested, however, that this relationship breaks down for catchments where slopes are at their threshold angle of stability because, in such cases, denudation is controlled by the rate of tectonic uplift through the rate of channel incision and frequency of slope failure. This mechanism is evaluated for the San Bernardino Mountains, California, a nascent range that incorporates both threshold hill-slopes and remnants of pre-uplift topography. Concentrations of in situ-produced cosmogenic 10Be in alluvial sediments are used to quantify catchment-wide denudation rates and show a broadly linear relationship with mean slope gradient up to ???30??: above this value denudation rates vary substantially for similar mean slope gradients. We propose that this decoupling in the slope gradient-denudation rate relationship marks the emergence of threshold topography and coincides with the transition from transport-limited to detachment-limited denudation. The survival in the San Bernardino Mountains of surfaces formed prior to uplift provides information on the topographic evolution of the range, in particular the transition from slope-gradient-dependent rates of denudation to a regime where denudation rates are controlled by rates of tectonic uplift. This type of transition may represent a general model for the denudational response to orogenic uplift and topographic evolution during the early stages of mountain building. ?? 2007 The Geological Society of America.

Comparison of various second-dimension gradient types in comprehensive two-dimensional liquid chromatography.

PubMed

Jandera, Pavel; Hájek, Tomás; Cesla, Petr

2010-06-01

Gradient elution provides significant improvement in peak capacity with respect to isocratic conditions. In the second dimension, gradients are limited to a short-time period available for separation. Various types of second-dimension gradients in comprehensive LC x LC are compared: (i) "full in fraction", (ii) "segment in fraction" and (iii) "continuously shifting" gradients, applied in orthogonal LC x LC separations of phenolic acids and flavones on a polyethylene glycol column in the first dimension and two types of porous shell fused-core C18 columns in the second dimension (Ascentis Express and Kinetex). The porous shell columns provide narrow bandwidths and fast second-dimension separations at moderate operating pressure that allows important savings of the overall separation time in comprehensive LC x LC separations. The effects of the gradient type on the bandwidths, theoretical peak capacity, separation time and column pressure in the second dimension were investigated. The type of gradient program controls the range of lipophilicity of sample compounds that can be separated in the second-dimension reversed-phase time period. This range can be calibrated using alkylbenzene standards, to design the separation conditions for complete sample separation, avoiding harmful wrap around of non-eluted compounds to the subsequent second-dimension fractions.

Subsurface temperatures and geothermal gradients on the north slope of Alaska

USGS Publications Warehouse

Collett, T.S.; Bird, K.J.; Magoon, L.B.

1993-01-01

On the North Slope of Alaska, geothermal gradient data are available from high-resolution, equilibrated well-bore surveys and from estimates based on well-log identification of the base of ice-bearing permafrost. A total of 46 North Slope wells, considered to be in or near thermal equilibrium, have been surveyed with high-resolution temperatures devices and geothermal gradients can be interpreted directly from these recorded temperature profiles. To augment the limited North Slope temperature data base, a new method of evaluating local geothermal gradients has been developed. In this method, a series of well-log picks for the base of the ice-bearing permafrost from 102 wells have been used, along with regional temperature constants derived from the high-resolution stabilized well-bore temperature surveys, to project geothermal gradients. Geothermal gradients calculated from the high-resolution temperature surveys generally agree with those projected from known ice-bearing permafrost depths over most of the North Slope. Values in the ice-bearing permafrost range from ??? 1.5??C 100 m in the Prudhoe Bay area to ??? 4.5??C 100 m in the east-central portion of the National Petroleum Reserve in Alaska. Geothermal gradients below the ice-bearing permafrost sequence range from ??? 1.6??C 100 m to ??? 5.2??C 100 m. ?? 1993.

Distribution, diversity patterns and faunogenesis of the millipedes (Diplopoda) of the Himalayas

PubMed Central

Golovatch, Sergei I.; Martens, Jochen

2018-01-01

Abstract The Himalayas support a highly rich, diverse, multi-layered, mostly endemic diplopod fauna which presently contains >270 species, 53 genera, 23 families and 13 orders. This is the result of mixing the ancient, apparently Tertiary and younger, Plio-Pleistocene elements of various origins, as well as the most recent anthropochore (= man-mediated) introductions. At the species and, partly, generic levels, the fauna is largely autochthonous and sylvicolous, formed through abounding in situ radiation and vicariance events. In general, the species from large genera and families tend to occupy a wide range of altitudes, but nearly each of the constituent species shows a distribution highly localized both horizontally and altitudinally, yet quite often with sympatry or even syntopy involved. The bulk of the fauna is Indo-Malayan in origin, with individual genera or families shared with those of SE Asia (mostly) and/or S India (few). Sino-Himalayan and, especially, Palaearctic components are subordinate, but also clearly distinguishable. PMID:29706770

Diversity of Carabidae (Insecta, Coleoptera) in epiphytic Bromeliaceae in central Veracruz, Mexico.

PubMed

Montes de Oca, E; Ball, G E; Spence, J R

2007-06-01

This paper documents the existence of carabid assemblages associated with bromeliads on the Cofre de Perote, Veracruz, Mexico. Based on bromeliads sampled over three altitudinal ranges, the assemblages included at least 26 species with an arboreal lifestyle and another 11 species that are not strictly arboreal. Seven species are new to science, urging us to pay attention to the arboreal fauna in forest conservation studies. Composition of carabid assemblages associated with bromeliads changes with altitude. In lowlands, it is comprised almost entirely of species of Lebiini, with the Platynini dominating assemblages found in bromeliads >1,000 m above sea level. Our data suggest that carabids use bromeliads to reduce stresses associated with drought periods, the exact timing of which depends on altitude. The unexpected low diversity of the carabid fauna associated with bromeliads at middle altitude is explained in terms of anthropogenic conversion of the original forest to pastureland. Given the importance of arboreal elements, further fragmentation of subtropical and tropical mountain forest significantly threatens overall carabid diversity.

Effects of CO[sub 2] and climate change on forest trees: Soil biology and enzymology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moldenke, A.R.; Baumeister, N.; Caldwell, B.A.

1994-06-01

Samples of Teracosm soils were analyzed shortly after initial setup to determine whether initial conditions were equivalent and matched expected values for local soils. Total and active fungal biomass, active bacterial biomass and protozoan numbers were reduced, with greatest decreases occurring in the A horizon. No effect was observed on total bacterial biomass, nematode or anthropod densities, but changes in nematode and arthropod species composition occurred. Significant differences in total density and species composition occurred between the enclosed Teracosms and the open controls. Arthropod and nematode community structure in the three altitudinal field sites had significantly diverged. No significant differencesmore » in activities of key soil enzymes in C- and N-cycling (acid phosphatase, protease, B-glucosidase, phenol oxidase and peroxidase) were found between initial samples relative to treatment, but all levels were significantly difference relative to depth in soil profile. Activities were within ranges previously observed in forests of the Pacific Northwest.« less

Mountain pastures of Qilian Shan: plant communities, grazing impact and degradation status (Gansu province, NW China)

NASA Astrophysics Data System (ADS)

Baranova, Alina; Schickhoff, Udo; Shunli, Wang; Ming, Jin

2015-04-01

Qilian Mountains are the water source region for the low arid reaches of HeiHe river basin (Gansu province, NW China). Due to overstocking and overgrazing during the last decades adverse ecological ef¬fects, in particular on soil properties and hydrological cycle, are to be expected in growing land areas. Vegetation cover is very important to prevent erosion process and to sustain stable subsurface runoff and ground water flow. The aim of this research is to identify plant communities, detecting grazing-induced and spatially differentiated changes in vegetation patterns, and to evaluate status of pasture land degradation.The study area is located in the spring/autumn pasture area of South Qilian Mountains between 2600-3600 m a.s.l., covering five main vegetation types: spruce forest, alpine shrubland, shrubby grassland, mountain grassland, degraded mountain grassland. In order to analyze gradual changes in vegetation patterns along altitudinal and grazing gradients and to classify related plant communities, quantitative and qualitative relevé data were collected (coverage, species composition, abundance of unpalatable plants, plant functional types, etc.). Vegetation was classified using hierarchical cluster analyses. Indirect Detrended Correspondence Analysis (DCA) was used to analyze variation in relationships between vegetation, environmental factors, and grazing impact. According to DCA results, distribution of the plant communities was strongly affected by altitude and exposition. Grassland floristic gradients showed greater dependence on grazing impact, which correlated contrarily with soil organic content, soil moisture and pH. Highest numbers of species richness and alpha diversity were detected in alpine shrubland vegetation type. Comparing the monitoring data for the recent nine years, a trend of deterioration, species successions and shift in dominant species becomes obvious. Species indicating degrading site environmental conditions were identified. Most of the grasslands have become secondary vegetation, with a considerable percentage of unpalatable, toxic and often thorny or spiny shrub and herb species that have a lower grazing value and rarely form a closed vegetation cover, at least in loess slopes. To prevent further degradation of the grassland and to sustain the diversity of the plant species (affecting the carrying capacity pastureland) appropriate pasture management strategy should be implemented.

Factors driving mortality and growth at treeline: a 30-year experiment of 92 000 conifers.

PubMed

Barbeito, Ignacio; Dawes, Melissa A; Rixen, Christian; Senn, Josef; Bebi, Peter

2012-02-01

Understanding the interplay between environmental factors contributing to treeline formation and how these factors influence different life stages remains a major research challenge. We used an afforestation experiment including 92 000 trees to investigate the spatial and temporal dynamics of tree mortality and growth at treeline in the Swiss Alps. Seedlings of three high-elevation conifer species (Larix decidua, Pinus mugo ssp. uncinata, and Pinus cembra) were systematically planted along an altitudinal gradient at and above the current treeline (2075 to 2230 m above sea level [a.s.l.]) in 1975 and closely monitored during the following 30 years. We used decision-tree models and generalized additive models to identify patterns in mortality and growth along gradients in elevation, snow duration, wind speed, and solar radiation, and to quantify interactions between the different variables. For all three species, snowmelt date was always the most important environmental factor influencing mortality, and elevation was always the most important factor for growth over the entire period studied. Individuals of all species survived at the highest point of the afforestation for more than 30 years, although mortality was greater above 2160 m a.s.l., 50-100 m above the current treeline. Optimal conditions for height growth differed from those for survival in all three species: early snowmelt (ca. day of year 125-140 [where day 1 is 1 January]) yielded lowest mortality rates, but relatively later snowmelt (ca. day 145-150) yielded highest growth rates. Although snowmelt and elevation were important throughout all life stages of the trees, the importance of radiation decreased over time and that of wind speed increased. Our findings provide experimental evidence that tree survival and height growth require different environmental conditions and that even small changes in the duration of snow cover, in addition to changes in temperature, can strongly impact tree survival and growth patterns at treeline. Further, our results show that the relative importance of different environmental variables for tree seedlings changes during the juvenile phase as they grow taller.

Diversity and feeding strategies of soil microfauna along elevation gradients in Himalayan cold deserts

PubMed Central

Háněl, Ladislav; Řeháková, Klára; Doležal, Jiří

2017-01-01

High-elevation cold deserts in Tibet and Himalaya are one of the most extreme environments. One consequence is that the diversity of macrofauna in this environment is often limited, and soil microorganisms have a more influential role in governing key surface and subsurface bioprocesses. High-elevation soil microfauna represent important components of cold ecosystems and dominant consumers of microbial communities. Still little is known about their diversity and distribution on the edge of their reproductive and metabolic abilities. In this study, we disentangle the impact of elevation and soil chemistry on diversity and distribution of rotifers, nematodes and tardigrades and their most frequent feeding strategies (microbial filter-feeders, bacterivores, fungivores, root-fungal feeders, omnivores) along two contrasting altitudinal gradients in Indian NW Himalaya (Zanskar transect from 3805 to 4714 m a.s.l.) and southwestern Tibet (Tso Moriri transect from 4477 to 6176 m a.s.l.), using a combination of multivariate analysis, variation partitioning and generalized additive models. Zanskar transect had higher precipitation, soil moisture, organic matter and available nutrients than dry Tso Moriri transect. In total, 40 species of nematodes, 19 rotifers and 1 tardigrade were discovered. Species richness and total abundance of rotifers and nematodes showed mid-elevation peaks in both investigated transects. The optimum for rotifers was found at higher elevation than for nematodes. Diversity and distribution of soil microfauna was best explained by soil nitrogen, phosphorus and organic matter. More fertile soils hosted more diverse and abundant faunal communities. In Tso Moriri, bacterivores represented 60% of all nematodes, fungivores 35%, root-fungal feeders 1% and omnivores 3%. For Zanskar the respective proportions were 21%, 13%, 56% and 9%. Elevational optima of different feeding strategies occurred in Zanskar in one elevation zone (4400–4500 m), while in Tso Moriri each feeding strategy had their unique optima with fungivores at 5300 m (steppes), bacterivores at 5500 m (alpine grassland), filter-feeders at 5600 m and predators and omnivores above 5700 m (subnival zone). Our results shed light on the diversity of microfauna in the high-elevation cold deserts and disentangle the role of different ecological filters in structuring microfaunal communities in the rapidly-warming Himalayas. PMID:29131839

Methods for Fabricating Gradient Alloy Articles with Multi-Functional Properties

NASA Technical Reports Server (NTRS)

Hofmann, Douglas C. (Inventor); Suh, Eric J. (Inventor); Borgonia, John Paul C. (Inventor); Dillon, Robert P. (Inventor); Mulder, Jerry L. (Inventor); Gardner, Paul B. (Inventor)

2015-01-01

Systems and methods for fabricating multi-functional articles comprised of additively formed gradient materials are provided. The fabrication of multi-functional articles using the additive deposition of gradient alloys represents a paradigm shift from the traditional way that metal alloys and metal/metal alloy parts are fabricated. Since a gradient alloy that transitions from one metal to a different metal cannot be fabricated through any conventional metallurgy techniques, the technique presents many applications. Moreover, the embodiments described identify a broad range of properties and applications.

The adaptation rate of a quantitative trait in an environmental gradient

NASA Astrophysics Data System (ADS)

Hermsen, R.

2016-12-01

The spatial range of a species habitat is generally determined by the ability of the species to cope with biotic and abiotic variables that vary in space. Therefore, the species range is itself an evolvable property. Indeed, environmental gradients permit a mode of evolution in which range expansion and adaptation go hand in hand. This process can contribute to rapid evolution of drug resistant bacteria and viruses, because drug concentrations in humans and livestock treated with antibiotics are far from uniform. Here, we use a minimal stochastic model of discrete, interacting organisms evolving in continuous space to study how the rate of adaptation of a quantitative trait depends on the steepness of the gradient and various population parameters. We discuss analytical results for the mean-field limit as well as extensive stochastic simulations. These simulations were performed using an exact, event-driven simulation scheme that can deal with continuous time-, density- and coordinate-dependent reaction rates and could be used for a wide variety of stochastic systems. The results reveal two qualitative regimes. If the gradient is shallow, the rate of adaptation is limited by dispersion and increases linearly with the gradient slope. If the gradient is steep, the adaptation rate is limited by mutation. In this regime, the mean-field result is highly misleading: it predicts that the adaptation rate continues to increase with the gradient slope, whereas stochastic simulations show that it in fact decreases with the square root of the slope. This discrepancy underscores the importance of discreteness and stochasticity even at high population densities; mean-field results, including those routinely used in quantitative genetics, should be interpreted with care.

The adaptation rate of a quantitative trait in an environmental gradient.

PubMed

Hermsen, R

2016-11-30

The spatial range of a species habitat is generally determined by the ability of the species to cope with biotic and abiotic variables that vary in space. Therefore, the species range is itself an evolvable property. Indeed, environmental gradients permit a mode of evolution in which range expansion and adaptation go hand in hand. This process can contribute to rapid evolution of drug resistant bacteria and viruses, because drug concentrations in humans and livestock treated with antibiotics are far from uniform. Here, we use a minimal stochastic model of discrete, interacting organisms evolving in continuous space to study how the rate of adaptation of a quantitative trait depends on the steepness of the gradient and various population parameters. We discuss analytical results for the mean-field limit as well as extensive stochastic simulations. These simulations were performed using an exact, event-driven simulation scheme that can deal with continuous time-, density- and coordinate-dependent reaction rates and could be used for a wide variety of stochastic systems. The results reveal two qualitative regimes. If the gradient is shallow, the rate of adaptation is limited by dispersion and increases linearly with the gradient slope. If the gradient is steep, the adaptation rate is limited by mutation. In this regime, the mean-field result is highly misleading: it predicts that the adaptation rate continues to increase with the gradient slope, whereas stochastic simulations show that it in fact decreases with the square root of the slope. This discrepancy underscores the importance of discreteness and stochasticity even at high population densities; mean-field results, including those routinely used in quantitative genetics, should be interpreted with care.

Active thermal fine laser tuning in a broad spectral range and optical properties of cholesteric liquid crystal.

PubMed

Jeong, Mi-Yun; Kwak, Keumcheol

2016-11-20

In this study, we achieved active fine laser tuning in a broad spectral range with dye-doped cholesteric liquid crystal wedge-type cells through temperature control. The spatial pitch gradient of each position of the wedge cell at room temperature was almost maintained after developing a temperature gradient. To achieve the maximum tuning range, the chiral dopant concentration, thickness, thickness gradient, and temperature gradient on the wedge cell should be matched properly. In order to understand the laser tuning mechanism for temperature change, we studied the temperature dependence of optical properties of the photonic bandgap of cholesteric liquid crystals. In our cholesteric liquid crystal samples, when temperature was increased, photonic bandgaps were shifted toward blue, while the width of the photonic bandgap was decreased, regardless of whether the helicity was left-handed or right-handed. This is mainly due to the combination of decreased refractive indices, higher molecular anisotropy of chiral molecules, and increased chiral molecular solubility. We envisage that this kind of study will prove useful in the development of practical active tunable CLC laser devices.

Plant responses to extreme climatic events: a field test of resilience capacity at the southern range edge.

PubMed

Herrero, Asier; Zamora, Regino

2014-01-01

The expected and already observed increment in frequency of extreme climatic events may result in severe vegetation shifts. However, stabilizing mechanisms promoting community resilience can buffer the lasting impact of extreme events. The present work analyzes the resilience of a Mediterranean mountain ecosystem after an extreme drought in 2005, examining shoot-growth and needle-length resistance and resilience of dominant tree and shrub species (Pinus sylvestris vs Juniperus communis, and P. nigra vs J. oxycedrus) in two contrasting altitudinal ranges. Recorded high vegetative-resilience values indicate great tolerance to extreme droughts for the dominant species of pine-juniper woodlands. Observed tolerance could act as a stabilizing mechanism in rear range edges, such as the Mediterranean basin, where extreme events are predicted to be more detrimental and recurrent. However, resistance and resilience components vary across species, sites, and ontogenetic states: adult Pinus showed higher growth resistance than did adult Juniperus; saplings displayed higher recovery rates than did conspecific adults; and P. nigra saplings displayed higher resilience than did P. sylvestris saplings where the two species coexist. P. nigra and J. oxycedrus saplings at high and low elevations, respectively, were the most resilient at all the locations studied. Under recurrent extreme droughts, these species-specific differences in resistance and resilience could promote changes in vegetation structure and composition, even in areas with high tolerance to dry conditions.

Plant Responses to Extreme Climatic Events: A Field Test of Resilience Capacity at the Southern Range Edge

PubMed Central

Herrero, Asier; Zamora, Regino

2014-01-01

The expected and already observed increment in frequency of extreme climatic events may result in severe vegetation shifts. However, stabilizing mechanisms promoting community resilience can buffer the lasting impact of extreme events. The present work analyzes the resilience of a Mediterranean mountain ecosystem after an extreme drought in 2005, examining shoot-growth and needle-length resistance and resilience of dominant tree and shrub species (Pinus sylvestris vs Juniperus communis, and P. nigra vs J. oxycedrus) in two contrasting altitudinal ranges. Recorded high vegetative-resilience values indicate great tolerance to extreme droughts for the dominant species of pine-juniper woodlands. Observed tolerance could act as a stabilizing mechanism in rear range edges, such as the Mediterranean basin, where extreme events are predicted to be more detrimental and recurrent. However, resistance and resilience components vary across species, sites, and ontogenetic states: adult Pinus showed higher growth resistance than did adult Juniperus; saplings displayed higher recovery rates than did conspecific adults; and P. nigra saplings displayed higher resilience than did P. sylvestris saplings where the two species coexist. P. nigra and J. oxycedrus saplings at high and low elevations, respectively, were the most resilient at all the locations studied. Under recurrent extreme droughts, these species-specific differences in resistance and resilience could promote changes in vegetation structure and composition, even in areas with high tolerance to dry conditions. PMID:24489971

Shifts in Postdiscrimination Gradients within a Stimulus Dimension Based on Bilateral Facial Symmetry

ERIC Educational Resources Information Center

Derenne, Adam

2010-01-01

A shift in generalization gradients away from S+ and towards stimuli on the opposite end of the stimulus dimension from S- is a well established phenomenon in the laboratory, occurring with humans and nonhumans and with a wide range of stimuli. The phenomenon of gradient shifts has also been observed to have an analogous relationship to a variety…

Systemic lupus erythematosus patients in the low-latitude plateau of China: altitudinal influences.

PubMed

Qian, G; Ran, X; Zhou, C X; Deng, D Q; Zhang, P L; Guo, Y; Luo, J H; Zhou, X H; Xie, H; Cai, M

2014-12-01

The current study was to investigate the features of hospitalized patients with systemic lupus erythematosus (SLE) at different altitudes. The correlation between SLE activity and altitudinal variations was also explored. Medical records of 1029 patients were retrospectively reviewed. Activity of SLE in each organ system was recorded using the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). There was no significant correlation between SLE activity and altitudes (r = 0.003, p = 0.159). Age at onset for SLE patients at high altitudes was significantly younger than that at low and moderate altitudes (p = 0.022 and p = 0.004, respectively). Age at SLE admission at low altitudes was significant older than those at moderate and high altitudes (p = 0.011 and p < 0.001, respectively). Patients at high altitudes had shorter duration from disease onset to admission than those at moderate altitudes (p = 0.009). Incidence of Sm antibodies-positive for resident patients at high altitudes was 36.4%, which were higher than that at moderate altitudes (p = 0.003). We found increasing trends of CNS activity in active patients; immunological and renal activities in inactive patients were correlated with elevated altitudes (p = 0.024, p = 0.004, p = 0.005), while arthritis scores in active patients showed the tendency of decreasing with the rise of elevation (p = 0.002). Hemoglobin level, red blood cell and platelet counts at high altitudes were significantly lower than those at low altitudes (p < 0.05, respectively). There was no significant difference in hemoglobin level between moderate- and low-altitude groups (p > 0.05). No significant difference in platelet counts between moderate- and high-altitude groups was observed (p > 0.05). Our findings suggest that some clinical features, laboratory tests and activity of main organs in SLE are influenced by altitudes. Furthermore, organ activities of active and inactive SLE patients have different patterns of altitudinal variations. These distinctive variations likely reveal that peculiar environmental factors at high altitudes can affect the development of SLE. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.