Total phenolic compounds, flavonoids, and radical scavenging activity of 21 selected tropical plants.

PubMed

Mustafa, R A; Abdul Hamid, A; Mohamed, S; Bakar, F Abu

2010-01-01

Free radical scavenging activity of 21 tropical plant extracts was evaluated using 1,1-diphenyl-2-picrylhydrazyl assay (DPPH). Total phenolic compounds and flavonoids were determined using Folin-Ciocalteu and HPLC, respectively. Results of the study revealed that all the plants tested exhibited excellent antioxidant activity with IC(50) in the range of 21.3 to 89.6 microg/mL. The most potent activity was demonstrated by Cosmos caudatus (21.3 microg/mL) and Piper betle (23.0 microg/mL) that are not significantly different than that of -tocopherol or BHA. L. inermis extract was found to consist of the highest concentration of phenolics, catechin, epicatechin, and naringenin. High content of quercetin, myricetin, and kaempferol were identified in Vitex negundo, Centella asiatica, and Sesbania grandiflora extracts, respectively. Luteolin and apigenin, on the other hand, were found in Premna cordifolia and Kaempferia galanga extracts. Strong correlation (R = 0.8613) between total phenolic compounds and total flavonoids (R = 0.8430) and that of antioxidant activity of the extracts were observed. The study revealed that phenolic, in particular flavonoids, may be the main contributors to the antioxidant activity exhibited by the plants. Potent antioxidant from natural sources is of great interest to replace the use of synthetic antioxidants. In addition, some of the plants have great potential to be used in the development of functional ingredients/foods that are currently in demand for the health benefits associated with their use.

Plant delta 15N correlates with the transpiration efficiency of nitrogen acquisition in tropical trees.

PubMed

Cernusak, Lucas A; Winter, Klaus; Turner, Benjamin L

2009-11-01

Based upon considerations of a theoretical model of (15)N/(14)N fractionation during steady-state nitrate uptake from soil, we hypothesized that, for plants grown in a common soil environment, whole-plant delta(15)N (deltaP) should vary as a function of the transpiration efficiency of nitrogen acquisition (F(N)/v) and the difference between deltaP and root delta(15)N (deltaP - deltaR). We tested these hypotheses with measurements of several tropical tree and liana species. Consistent with theoretical expectations, both F(N)/v and deltaP - deltaR were significant sources of variation in deltaP, and the relationship between deltaP and F(N)/v differed between non-N(2)-fixing and N(2)-fixing species. We interpret the correlation between deltaP and F(N)/v as resulting from variation in mineral nitrogen efflux-to-influx ratios across plasma membranes of root cells. These results provide a simple explanation of variation in delta(15)N of terrestrial plants and have implications for understanding nitrogen cycling in ecosystems.

Plant Diversity in Live Fences and Pastures, Two Examples from the Mexican Humid Tropics

NASA Astrophysics Data System (ADS)

Ruiz-Guerra, Betsabé; Rosas, Noé Velázquez; López-Acosta, Juan Carlos

2014-09-01

This study analyzes the potential uses of live fences and pastures as reservoirs of plant diversity for two regions with different management histories, Los Tuxtlas (LT) and Uxpanapa (UX), Veracruz, México. We studied two habitats, live fences and pastures, analyzed their species richness, diversity, structure and plant composition and classified species according to plant regeneration modes (light-demanding and shade tolerant), seed dispersal syndrome and their local uses. We recorded 62 species of trees at LT and 48 at UX. Live fences were more diverse than pastures in both regions. The LT site showed to analyze the relationship a higher diversity of plants in regeneration stages than the one at UX. However, UX had higher diversity of adult plants in the pastures than LT. Composition and structure of live fences were different between regions, as well as within live fences and pastures, 53 % of species were light-demanding and 40 % were shade tolerant; 70 % of the species were dispersed by birds. Differences between sites are associated with the modifications in live fences structure, which changed according to managerial practices and the use of local species; this may influence plant regeneration modes as well as the visits of avian dispersal agents. In LT, all species found in live fences were useful to humans, whereas in UX, less than half were used by the local population. Our results underline the importance of live fences and isolated trees in pasture habitats as potential sites to host native and useful species from tropical rain forests in livestock landscapes.

An AFLP estimation of the outcrossing rate of Spondias tuberosa (Anacardiaceae), an endemic species to the Brazilian semiarid region.

PubMed

Fernandes Santos, Carlos Antonio; de Souza Gama, Renata Natália Cândido

2013-06-01

The umbu tree (Spondias tuberosa) is one of the most important endemic species to the Brazilian tropical semiarid region. The umbu tree has edible fruits with a peculiar flavor that are consumed in natura or in a semi-industrialized form, such as jams, candies and juices. The majority of endemic species to Brazilian semiarid region have not been studied or sampled to form germ-plasm collections, which increases the risk of losing genetic variability of the adapted species to xerophytic conditions. The aim of this study was to estimate outcrossing rates in S. tuberosa using a multilocus mixed model in order to guide genetic resources and breeding programs of this species. DNA samples were extracted from 92 progenies of umbu trees, which were distributed among 12 families. These trees were planted by seed in 1991 in Petrolina, PE, Brazil. The experimental design was a randomized block, with a total of 42 progenies sampled in three regions. The experimental units were composed by five plants and five replications. The outcrossing rate was estimated by the multilocus model, which is available in the MLTR software, and was based on 17 polymorphic AFLP bands obtained from AAA_CTG and AAA_CTC primer combinations. The observed heterozygotes ranged from 0.147 to 0.499, with a maximum frequency estimated for the AAA_CTC 10 amplicon. The multilocus outcrossing estimation (t(m)) was 0.804 +/- 0.072, while the single-locus (t(s)) was 0.841 +/- 0.079, which suggests that S. tuberosa is predominantly an outcrossing species. The difference between t(m) and t(s) was -0.037 +/- 0.029, which indicates that biparental inbreeding was nearly absent. The mean inbreeding coefficient or fixation index (F) among maternal plants was--0.103 +/- 0.045, and the expected F was 0.108, which indicates that there was no excess of heterozygotes in the maternal population. The outcrossing estimates obtained in the present study indicate that S. tuberosa is an open-pollinated species. Biometrical

Soil nutrients influence spatial distributions of tropical trees species

USGS Publications Warehouse

John, R.; Dalling, J.W.; Harms, K.E.; Yavitt, J.B.; Stallard, R.F.; Mirabello, M.; Hubbell, S.P.; Valencia, R.; Navarrete, H.; Vallejo, M.; Foster, R.B.

2007-01-01

The importance of niche vs. neutral assembly mechanisms in structuring tropical tree communities remains an important unsettled question in community ecology [Bell G (2005) Ecology 86:1757-1770]. There is ample evidence that species distributions are determined by soils and habitat factors at landscape (0.5 million individual trees of 1,400 species and 10 essential plant nutrients, we used Monte Carlo simulations of species distributions to test plant-soil associations against null expectations based on dispersal assembly. We found that the spatial distributions of 36-51% of tree species at these sites show strong associations to soil nutrient distributions. Neutral dispersal assembly cannot account for these plant-soil associations or the observed niche breadths of these species. These results indicate that belowground resource availability plays an important role in the assembly of tropical tree communities at local scales and provide the basis for future investigations on the mechanisms of resource competition among tropical tree species. ?? 2007 by The National Academy of Sciences of the USA.

Ranching modernization in tropical Brazil: foreign investment and environment in Mato Grosso, 1900-1950.

PubMed

Wilcox, Robert W

2008-01-01

Accompanying the expansion of modern beef production in the nineteenth and twentieth centuries were technologies and methods that proponents assumed were applicable to all ecosystems. successes in Europe, the United States, and Argentina convinced ranchers, investors, and animal scientists that these could be applied in the tropical Americas with ease. This assumption contributed to a wave of foreign ranching investment in semi-tropical Mato Grosso, Brazil, beginning in the early twentieth century. However, such a view failed to consider the specific characteristics of such environments and led to difficulties for several ventures and a re-evaluation of the relationship between ecosystems and the type of ranching appropriate to them. Ultimately, local Brazilian practice and experimentation proved more successful in tropical and semi-tropical Brazil, forcing foreign ranching concerns to adapt their techniques. Following the logic of earlier decades, more recently cattle-raising practices developed in Mato Grosso and similar regions have been applied in the tropical Amazon, resulting in widespread ecological devastation. The uneven experiences of foreign entrepreneurs in Mato Grosso offer valuable lessons for understanding the application of modernization technologies to diverse ecosystems; such knowledge can lead to a more sustainable approach to meat production.

Anthropogenic disturbance in tropical forests can double biodiversity loss from deforestation.

PubMed

Barlow, Jos; Lennox, Gareth D; Ferreira, Joice; Berenguer, Erika; Lees, Alexander C; Mac Nally, Ralph; Thomson, James R; Ferraz, Silvio Frosini de Barros; Louzada, Julio; Oliveira, Victor Hugo Fonseca; Parry, Luke; Solar, Ricardo Ribeiro de Castro; Vieira, Ima C G; Aragão, Luiz E O C; Begotti, Rodrigo Anzolin; Braga, Rodrigo F; Cardoso, Thiago Moreira; de Oliveira, Raimundo Cosme; Souza, Carlos M; Moura, Nárgila G; Nunes, Sâmia Serra; Siqueira, João Victor; Pardini, Renata; Silveira, Juliana M; Vaz-de-Mello, Fernando Z; Veiga, Ruan Carlo Stulpen; Venturieri, Adriano; Gardner, Toby A

2016-07-07

Concerted political attention has focused on reducing deforestation, and this remains the cornerstone of most biodiversity conservation strategies. However, maintaining forest cover may not reduce anthropogenic forest disturbances, which are rarely considered in conservation programmes. These disturbances occur both within forests, including selective logging and wildfires, and at the landscape level, through edge, area and isolation effects. Until now, the combined effect of anthropogenic disturbance on the conservation value of remnant primary forests has remained unknown, making it impossible to assess the relative importance of forest disturbance and forest loss. Here we address these knowledge gaps using a large data set of plants, birds and dung beetles (1,538, 460 and 156 species, respectively) sampled in 36 catchments in the Brazilian state of Pará. Catchments retaining more than 69–80% forest cover lost more conservation value from disturbance than from forest loss. For example, a 20% loss of primary forest, the maximum level of deforestation allowed on Amazonian properties under Brazil’s Forest Code, resulted in a 39–54% loss of conservation value: 96–171% more than expected without considering disturbance effects. We extrapolated the disturbance-mediated loss of conservation value throughout Pará, which covers 25% of the Brazilian Amazon. Although disturbed forests retained considerable conservation value compared with deforested areas, the toll of disturbance outside Pará’s strictly protected areas is equivalent to the loss of 92,000–139,000 km2 of primary forest. Even this lowest estimate is greater than the area deforested across the entire Brazilian Amazon between 2006 and 2015 (ref. 10). Species distribution models showed that both landscape and within-forest disturbances contributed to biodiversity loss, with the greatest negative effects on species of high conservation and functional value. These results demonstrate an urgent need

Natural biological control of pest mites in Brazilian sun coffee agroecosystems.

PubMed

Teodoro, Adenir V; Sarmento, Renato A; Rêgo, Adriano S; da Graça S Maciel, Anilde

2010-06-01

Coffee is one of the leading commodities in tropical America. Although plantations are usually established under a canopy of trees in most producing countries in the region, Brazilian coffee is mostly produced under full sun conditions. Such simple, single-crop agroecosystems with intensive agrochemical inputs often suffer with pests like mites. Predatory mites of the family Phytoseiidae are the main natural enemies associated with pest mites in the field. However, these beneficial arthropods struggle to survive in intensive agroecosystems such as coffee monocultures due to unfavorable microclimatic conditions, widespread pesticide use, and lack of alternative food (pollen, nectar). Conservation biological control uses a range of management strategies to sustain and enhance populations of indigenous natural enemies such as predatory mites. We discuss here conservation biological control as a strategy to improve biological control of pest mites by native predatory mites in Brazilian coffee monocultures as well as some related patents.

Testing the stress-gradient hypothesis during the restoration of tropical degraded land using the shrub Rhodomyrtus tomentosa as a nurse plant

Treesearch

Nan Liu; Hai Ren; Sufen Yuan; Qinfeng Guo; Long Yang

2013-01-01

The relative importance of facilitation and competition between pairwise plants across abiotic stress gradients as predicted by the stress-gradient hypothesis has been confirmed in arid and temperate ecosystems, but the hypothesis has rarely been tested in tropical systems, particularly across nutrient gradients. The current research examines the interactions between a...

Tropical rain forest biogeochemistry in a warmer world: initial results from a novel warming experiment in a Puerto Rico tropical forest

NASA Astrophysics Data System (ADS)

Reed, S.; Cavaleri, M. A.; Alonso-Rodríguez, A. M.; Kimball, B. A.; Wood, T. E.

2016-12-01

Tropical forests represent one of the planet's most active biogeochemical engines. They account for the dominant proportion of Earth's live terrestrial plant biomass, nearly one-third of all soil carbon, and exchange more CO2 with the atmosphere than any other biome. In the coming decades, the tropics will experience extraordinary changes in temperature, and our understanding of how this warming will affect biogeochemical cycling remains notably poor. Given the large amounts of carbon tropical forests store and cycle, it is no surprise that our limited ability to characterize tropical forest responses to climate change may represent the largest hurdle in accurately predicting Earth's future climate. Here we describe initial results from the world's first tropical forest field warming experiment, where forest understory plants and soils are being warmed 4 °C above ambient temperatures. This Tropical Responses to Altered Climate Experiment (TRACE) was established in a rain forest in Puerto Rico to investigate the effects of increased temperature on key biological processes that control tropical forest carbon cycling, and to establish the steps that need to be taken to resolve the uncertainties surrounding tropical forest responses to warming. In this talk we will describe the experimental design, as well as the wide range of measurements being conducted. We will also present results from the initial phase of warming, including data on how increased temperatures from infrared lamp warming affected soil moisture, soil respiration rates, a suite of carbon pools, soil microbial biomass, nutrient availability, and the exchange of elements between leaf litter and soil. These data represent a first look into tropical rain forest responses to an experimentally-warmed climate in the field, and provide exciting insight into the non-linear ways tropical biogeochemical cycles respond to change. Overall, we strive to improve Earth System Model parameterization of the pools and

Western Tropical Atlantic Hydrologic change during the last 130,000 years

NASA Astrophysics Data System (ADS)

McGrath, S. M.; Lavoie, N.; Oppo, D.

2016-12-01

Abrupt climate changes in the North Atlantic during the last 130,000 years are associated with hydrologic changes in the western tropical Atlantic Ocean. Previous studies on marine sediment cores from between 4°S and the equator have documented pulses of terrigenous sediment recording increased precipitation and weathering on the Brazilian Nordeste associated with Heinrich events. We worked on cores KNR197-3-11CDH (7°40'N, 53°49'W, water depth 550 m) and KNR 197-3-46CDH (7°50.1621'N, 53°39.8051'W, 947m water depth) located farther north along the South American continental slope, where sediment derives from the Amazon river basin and is transported by the North Brazilian Current. Preliminary stratigraphy based on magnetic susceptibility shows a possible correlation with the Greenland ice core δ18O stratigraphy. We use sediment elemental composition, determined by x-ray fluorescence (XRF) to evaluate variations in terrigenous sediment runoff and δ18O of the planktonic foraminifers Globierinoides ruber to evaluate variations in western tropical North Atlantic surface hydrography across North Atlantic abrupt climate events. Similarities and differences among our records and the records from the more southerly cores will help understand the mechanisms of hydrologic changes in the regions on abrupt climate time scales.

The six-eyed sand spiders of the genus Sicarius (Araneae: Haplogynae: Sicariidae) from the Brazilian Caatinga.

PubMed

Magalhães, Ivan L F; Brescovit, Antonio D; Santos, Adalberto J

2013-01-04

In this paper we revise the species of Sicarius (Araneae: Sicariidae) from the Brazilian Caatinga, the largest tropical dry forest nucleus in the world. We redescribe, designate a neotype and provide new records for Sicarius tropicus (Mello- Leitão, 1936), the only species previously known from the region, and describe three new species: S. cariri n. sp., S. diadorim n. sp. and S. ornatus n. sp. We report high intraspecific variation in the genitalic morphology of these species, especially in females. We also provide anecdotal observations on natural history and behavior of these species, including diet, mating behavior and clutch size. We include an identification key for Brazilian Caatinga species of Sicarius.

The biogeochemical heterogeneity of tropical forests.

PubMed

Townsend, Alan R; Asner, Gregory P; Cleveland, Cory C

2008-08-01

Tropical forests are renowned for their biological diversity, but also harbor variable combinations of soil age, chemistry and susceptibility to erosion or tectonic uplift. Here we contend that the combined effects of this biotic and abiotic diversity promote exceptional biogeochemical heterogeneity at multiple scales. At local levels, high plant diversity creates variation in chemical and structural traits that affect plant production, decomposition and nutrient cycling. At regional levels, myriad combinations of soil age, soil chemistry and landscape dynamics create variation and uncertainty in limiting nutrients that do not exist at higher latitudes. The effects of such heterogeneity are not well captured in large-scale estimates of tropical ecosystem function, but we suggest new developments in remote sensing can help bridge the gap.

Plant competition and the implications for tropical forest carbon dynamics

NASA Astrophysics Data System (ADS)

Schnitzer, Stefan

2016-04-01

Tropical forests store more than one third of all terrestrial carbon and account for over one third of terrestrial net primary productivity, and thus they are a critical component of the global carbon cycle. Nearly all of the aboveground carbon in tropical forests is held in tree biomass, and long-term carbon fluxes are balanced largely by tree growth and tree death. Therefore, the vast majority of research on tropical forest carbon dynamics has focused on the growth and mortality of canopy trees. By contrast, lianas (woody vines) contribute little biomass relative to trees. However, competition between lianas (woody vines) and trees may result in forest-wide carbon loss if lianas fail to accumulate the carbon that they displace in trees. We tested this hypotheses using a series of large-scale liana-removal studies in the Republic of Panama. We found that lianas limited tree growth and increased tree mortality, thus significantly reducing carbon accumulation in trees. Lianas themselves, however, did not compensate for the carbon that they displaced in trees. Lianas lower the capacity of tropical forests to uptake and store carbon, and the recently observed increases in liana abundance in neotropical forests will likely result in further reductions of carbon uptake.

Water hyacinth as indicator of heavy metal pollution the tropics

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

Gonzalez, H.; Otero, M.; Lodenius, M.

1989-12-01

The water hyacinth (Eichhornia crassipes) is a common aquatic plant in many tropical countries. Its ability absorb nutrients and other elements from the water has made it possible to use it for water purification purposes. Eichhornia, especially stems and leaves, have been successfully used as indicators of heavy metal pollution in tropical countries. The uptake of heavy metals in this plant is stronger in the roots than in the floating shoots. Metallothionein-like compounds have been found from roots of this species after cadmium exposure. The purpose of this investigation was to study the possibilities of using roots of water hyacinthmore » as a biological indicator of metal pollution in tropical aquatic ecosystems.« less

[Edema and the tropics].

PubMed

Holzer, B R

2004-11-01

People visiting or living in tropical or subtropical regions are exposed to various factors, which can lead to edema. Tourists staying for only a short time in the tropics are exposed to different risks, with other disease patterns, than people living in the tropics or immigrants from tropical regions. The differential diagnosis of edema and swelling is extensive and it can sometimes be difficult to distinguish classical edema with fluid retention in the extravascular interstitial space, from lymphedema or swelling due to other aetiologies. The patients often connect the edema to their stay in the tropics although it may have been pre-existing with no obvious relation to their travels. Already the long trip in the plane can lead to an "economy class syndrome" due to deep venous thrombosis. Contacts with animal or plant toxins, parasites or parasitic larvae can produce peripheral edema. The diagnosis can often only be made by taking a meticulous history, checking for eosinophilia and with the help of serological investigations. Chronic lymphedema or elephantiasis of the limbs is often due to blocked lymph vessels by filarial worms. It has to be distinguished from other forms as e.g. podoconiosis due to blockage by mineral particles in barefoot walking people. The trend to book adventure and trekking holidays at high altitude leads to high altitude peripheral edema or non-freezing cold injuries such as frostbites and trench foot. Edema can be an unwanted side effect of a range of drugs e.g. nifedipine, which is used to prevent and treat high altitude pulmonary edema. Protein malnutrition, (Kwashiorkor), and vitamin B6 deficiency, (Beri-Beri) are very rarely observed in immigrants and almost never in tourists. A very painful swelling of fingers and hands in children and young adults of African origin can be observed during a sickle cell crisis. Many protein loosing nephropathies connected with plant and animal toxins but also bacterial, viral or parasitic agents, can

A biogeographical study on tropical flora of southern China.

PubMed

Zhu, Hua

2017-12-01

The tropical climate in China exists in southeastern Xizang (Tibet), southwestern to southeastern Yunnan, southwestern Guangxi, southern Guangdon, southern Taiwan, and Hainan, and these southern Chinese areas contain tropical floras. I checked and synonymized native seed plants from these tropical areas in China and recognized 12,844 species of seed plants included in 2,181 genera and 227 families. In the tropical flora of southern China, the families are mainly distributed in tropical areas and extend into temperate zones and contribute to the majority of the taxa present. The genera with tropical distributions also make up the most of the total flora. In terms of geographical elements, the genera with tropical Asian distribution constitute the highest proportion, which implies tropical Asian or Indo-Malaysia affinity. Floristic composition and geographical elements are conspicuous from region to region due to different geological history and ecological environments, although floristic similarities from these regions are more than 90% and 64% at the family and generic levels, respectively, but lower than 50% at specific level. These differences in the regional floras could be influenced by historical events associated with the uplift of the Himalayas, such as the southeastward extrusion of the Indochina geoblock, clockwise rotation and southeastward movement of Lanping-Simao geoblock, and southeastward movement of Hainan Island. The similarity coefficients between the flora of southern China and those of Indochina countries are more than 96% and 80% at family and generic levels, indicating their close floristic affinity and inclusion in the same biogeographically floristic unit.

Loss of soil (macro)fauna due to the expansion of Brazilian sugarcane acreage.

PubMed

Franco, André L C; Bartz, Marie L C; Cherubin, Maurício R; Baretta, Dilmar; Cerri, Carlos E P; Feigl, Brigitte J; Wall, Diana H; Davies, Christian A; Cerri, Carlos C

2016-09-01

Land use changes (LUC) from pasture to sugarcane (Saccharum spp.) crop are expected to add 6.4Mha of new sugarcane land by 2021 in the Brazilian Cerrado and Atlantic Forest biomes. We assessed the effects of these LUC on the abundance and community structure of animals that inhabit soils belowground through a field survey using chronosequences of land uses comprising native vegetation, pasture, and sugarcane along a 1000-km-long transect across these two major tropical biomes in Brazil. Macrofauna community composition differed among land uses. While most groups were associated with samples taken in native vegetation, high abundance of termites and earthworms appeared associated with pasture soils. Linear mixed effects analysis showed that LUC affected total abundance (X(2)(1)=6.79, p=0.03) and taxa richness (X(2)(1)=6.08, p=0.04) of soil macrofauna. Abundance increased from 411±70individualsm(-2) in native vegetation to 1111±202individualsm(-2) in pasture, but decreased sharply to 106±24individualsm(-2) in sugarcane soils. Diversity decreased 24% from native vegetation to pasture, and 39% from pasture to sugarcane. Thus, a reduction of ~90% in soil macrofauna abundance, besides a loss of ~40% in the diversity of macrofauna groups, can be expected when sugarcane crops replace pasture in Brazilian tropical soils. In general, higher abundances of major macrofauna groups (ants, coleopterans, earthworms, and termites) were associated with higher acidity and low contents of macronutrients and organic matter in soil. This study draws attention for a significant biodiversity loss belowground due to tropical LUC in sugarcane expansion areas. Given that many groups of soil macrofauna are recognized as key mediators of ecosystem processes such as soil aggregation, nutrients cycling and soil carbon storage, our results warrant further efforts to understand the impacts of altering belowground biodiversity and composition on soil functioning and agriculture performance

Functional strategies of tropical dry forest plants in relation to growth form and isotopic composition

NASA Astrophysics Data System (ADS)

Santiago, L. S.; Silvera, K.; Andrade, J. L.; Dawson, T. E.

2017-11-01

Tropical dry forests (TDFs) undergo a substantial dry season in which plant species must endure several months of drought. Although TDFs support a diverse array of plant growth forms, it is not clear how they vary in mechanisms for coping with seasonal drought. We measured organic tissue stable isotopic composition of carbon (δ13C) and nitrogen (δ15N) across six plant growth forms including epiphytes, terrestrial succulents, trees, shrubs, herbs, and vines, and oxygen (δ18O) of four growth forms, to distinguish among patterns of resource acquisition and evaluate mechanisms for surviving annual drought in a lowland tropical dry forest in Yucatan, Mexico. Terrestrial succulent and epiphyte δ13C was around -14‰, indicating photosynthesis through the Crassulacean acid metabolism pathway, and along with one C4 herb were distinct from mean values of all other growth forms, which were between -26 and -29‰ indicating C3 photosynthesis. Mean tissue δ15N across epiphytes was -4.95‰ and was significantly lower than all other growth forms, which had values around +3‰. Tissue N concentration varied significantly among growth forms with epiphytes and terrestrial succulents having significantly lower values of about 1% compared to trees, shrubs, herbs and vines, which were around 3%. Tissue C concentration was highest in trees, shrubs and vines, intermediate in herbs and epiphytes and lowest in terrestrial succulents. δ18O did not vary among growth forms. Overall, our results suggest several water-saving aspects of resource acquisition, including the absolute occurrence of CAM photosynthesis in terrestrial succulents and epiphytes, high concentrations of leaf N in some species, which may facilitate CO2 drawdown by photosynthetic enzymes for a given stomatal conductance, and potentially diverse N sources ranging from atmospheric N in epiphytes with extremely depleted δ15N values, and a large range of δ15N values among trees, many of which are legumes and dry season

Large-scale patterns of benthic marine communities in the Brazilian Province.

PubMed

Aued, Anaide W; Smith, Franz; Quimbayo, Juan P; Cândido, Davi V; Longo, Guilherme O; Ferreira, Carlos E L; Witman, Jon D; Floeter, Sergio R; Segal, Bárbara

2018-01-01

As marine ecosystems are influenced by global and regional processes, standardized information on community structure has become crucial for assessing broad-scale responses to natural and anthropogenic disturbances. Extensive biogeographic provinces, such as the Brazilian Province in the southwest Atlantic, present numerous theoretical and methodological challenges for understanding community patterns on a macroecological scale. In particular, the Brazilian Province is composed of a complex system of heterogeneous reefs and a few offshore islands, with contrasting histories and geophysical-chemical environments. Despite the large extent of the Brazilian Province (almost 8,000 kilometers), most studies of shallow benthic communities are qualitative surveys and/or have been geographically restricted. We quantified community structure of shallow reef habitats from 0° to 27°S latitude using a standard photographic quadrat technique. Percent cover data indicated that benthic communities of Brazilian reefs were dominated by algal turfs and frondose macroalgae, with low percent cover of reef-building corals. Community composition differed significantly among localities, mostly because of their macroalgal abundance, despite reef type or geographic region, with no evident latitudinal pattern. Benthic diversity was lower in the tropics, contrary to the general latitudinal diversity gradient pattern. Richness peaked at mid-latitudes, between 20°S to 23°S, where it was ~3.5-fold higher than localities with the lowest richness. This study provides the first large-scale description of benthic communities along the southwestern Atlantic, providing a baseline for macroecological comparisons and evaluation of future impacts. Moreover, the new understanding of richness distribution along Brazilian reefs will contribute to conservation planning efforts, such as management strategies and the spatial prioritization for the creation of new marine protected areas.

Large-scale patterns of benthic marine communities in the Brazilian Province

PubMed Central

Smith, Franz; Quimbayo, Juan P.; Cândido, Davi V.; Longo, Guilherme O.; Ferreira, Carlos E. L.; Witman, Jon D.; Floeter, Sergio R.; Segal, Bárbara

2018-01-01

As marine ecosystems are influenced by global and regional processes, standardized information on community structure has become crucial for assessing broad-scale responses to natural and anthropogenic disturbances. Extensive biogeographic provinces, such as the Brazilian Province in the southwest Atlantic, present numerous theoretical and methodological challenges for understanding community patterns on a macroecological scale. In particular, the Brazilian Province is composed of a complex system of heterogeneous reefs and a few offshore islands, with contrasting histories and geophysical-chemical environments. Despite the large extent of the Brazilian Province (almost 8,000 kilometers), most studies of shallow benthic communities are qualitative surveys and/or have been geographically restricted. We quantified community structure of shallow reef habitats from 0° to 27°S latitude using a standard photographic quadrat technique. Percent cover data indicated that benthic communities of Brazilian reefs were dominated by algal turfs and frondose macroalgae, with low percent cover of reef-building corals. Community composition differed significantly among localities, mostly because of their macroalgal abundance, despite reef type or geographic region, with no evident latitudinal pattern. Benthic diversity was lower in the tropics, contrary to the general latitudinal diversity gradient pattern. Richness peaked at mid-latitudes, between 20°S to 23°S, where it was ~3.5-fold higher than localities with the lowest richness. This study provides the first large-scale description of benthic communities along the southwestern Atlantic, providing a baseline for macroecological comparisons and evaluation of future impacts. Moreover, the new understanding of richness distribution along Brazilian reefs will contribute to conservation planning efforts, such as management strategies and the spatial prioritization for the creation of new marine protected areas. PMID:29883496

Inhibitory activity of α-amylase and α-glucosidase by plant extracts from the Brazilian cerrado.

PubMed

Souza, Paula Monteiro de; Sales, Paloma Michelle de; Simeoni, Luiz Alberto; Silva, Elton Clementino; Silveira, Dâmaris; Magalhães, Pérola de Oliveira

2012-03-01

Diabetes mellitus is the most common disease in the world. One therapeutic approach for treating diabetes is inhibition of α-amylase and α-glucosidase activities to reduce postprandial blood glucose levels. In vitro tests showed that several plant extracts from Brazilian cerrado species can inhibit the activity of α-amylase and α-glucosidase. The extracts of Eugenia dysenterica, Stryphnodendron adstringens, Pouteria caimito, Pouteria ramiflora, and Pouteria torta showed strong α-amylase and α-glucosidase inhibitory activity. Eugenia dysenterica, P. caimito, P. ramiflora, and P. torta aqueous extracts exerted the highest activity against α-amylase (IC₅₀) values of 14.93, 13.6, 7.08, and 5.67 µg/mL, respectively) and α-glucosidase (IC₅₀ values of 0.46, 2.58, 0.35, and 0.22 µg/mL, respectively). Stryphnodendron adstringens ethanol extract also exhibited inhibitory activity against both enzymes (IC₅₀) 1.86 µg/mL against α-amylase and 0.61 µg/mL against α-glucosidase). The results suggest that the activity of these cerrado plants on α-amylase and α-glucosidase represents a potential tool for development of new strategies for treatment of diabetes. © Georg Thieme Verlag KG Stuttgart · New York.

Effects of plants containing secondary compounds and plant oils on rumen fermentation and ecology.

PubMed

Wanapat, Metha; Kongmun, Pongthon; Poungchompu, Onanong; Cherdthong, Anusorn; Khejornsart, Pichad; Pilajun, Ruangyote; Kaenpakdee, Sujittra

2012-03-01

A number of experiments have been conducted to investigate effects of tropical plants containing condensed tannins and/or saponins present in tropical plants and some plant oils on rumen fermentation and ecology in ruminants. Based on both in vitro and in vivo trials, the results revealed important effects on rumen microorganisms and fermentation including methane production. Incorporation and/or supplementation of these plants containing secondary metabolites have potential for improving rumen ecology and subsequently productivity in ruminants.

Contribution of seagrass plants to CO2 capture in a tropical seagrass meadow under experimental disturbance.

PubMed

Deyanova, Diana; Gullström, Martin; Lyimo, Liberatus D; Dahl, Martin; Hamisi, Mariam I; Mtolera, Matern S P; Björk, Mats

2017-01-01

Coastal vegetative habitats are known to be highly productive environments with a high ability to capture and store carbon. During disturbance this important function could be compromised as plant photosynthetic capacity, biomass, and/or growth are reduced. To evaluate effects of disturbance on CO2 capture in plants we performed a five-month manipulative experiment in a tropical seagrass (Thalassia hemprichii) meadow exposed to two intensity levels of shading and simulated grazing. We assessed CO2 capture potential (as net CO2 fixation) using areal productivity calculated from continuous measurements of diel photosynthetic rates, and estimates of plant morphology, biomass and productivity/respiration (P/R) ratios (from the literature). To better understand the plant capacity to coping with level of disturbance we also measured plant growth and resource allocation. We observed substantial reductions in seagrass areal productivity, biomass, and leaf area that together resulted in a negative daily carbon balance in the two shading treatments as well as in the high-intensity simulated grazing treatment. Additionally, based on the concentrations of soluble carbohydrates and starch in the rhizomes, we found that the main reserve sources for plant growth were reduced in all treatments except for the low-intensity simulated grazing treatment. If permanent, these combined adverse effects will reduce the plants' resilience and capacity to recover after disturbance. This might in turn have long-lasting and devastating effects on important ecosystem functions, including the carbon sequestration capacity of the seagrass system.

Stranding Events of Kogia Whales along the Brazilian Coast.

PubMed

Moura, Jailson F; Acevedo-Trejos, Esteban; Tavares, Davi C; Meirelles, Ana C O; Silva, Cristine P N; Oliveira, Larissa R; Santos, Roberta A; Wickert, Janaína C; Machado, Rodrigo; Siciliano, Salvatore; Merico, Agostino

2016-01-01

The genus Kogia, which comprises only two extant species, Kogia sima and Kogia breviceps, represents one of the least known groups of cetaceans in the global ocean. In some coastal regions, however, stranding events of these species have been relatively common over the last decades. Stranding provides the opportunity to investigate the biology of these cetaceans and to explore the epidemiological aspects associated with the mortality of the organisms found on the beach. A number of disturbances (including pelagic fisheries, chemical pollution, boat strikes, and noise pollution) have been confirmed to pose a particular threat to the Kogia species. However, no study has yet investigated potential relationships between environmental conditions and stranding events. Here we analyse how a collection of environmental, physical, and biological variables, such as wind, sea surface temperature (SST), water depth, and chlorophyll-a, correlate to Kogia stranding events along the Brazilian coast. The results of our statistical analyses suggest that K. sima is more likely found in warm tropical waters, which provide an explanation for the high frequency of stranding in northeastern Brazilian coast. In contrast, K. breviceps appears to have a preference for temperate and productive waters. Wind speed results to be also an important factor for predicting Kogia strandings in Brazilian coast. Additionally, literature information in combination with our own data and analyses of stomach contents confirms that oceanic cephalopods constitute the primary nutritional source of both Kogia species. By using the available information as a qualitative proxy for habitat preference and feeding ecology, our study provides a novel and comprehensive assessment of Kogia stranding data in relation to environmental conditions along the Brazilian coast.

Neglected tropical diseases in Brazil.

PubMed

Lindoso, José Angelo L; Lindoso, Ana Angélica B P

2009-01-01

Poverty is intrinsically related to the incidence of Neglected Tropical Diseases (NTDs). The main countries that have the lowest human development indices (HDI) and the highest burdens of NTDs are located in tropical and subtropical regions of the world. Among these countries is Brazil, which is ranked 70th in HDI. Nine out of the ten NTDs established by the World Health Organization (WHO) are present in Brazil. Leishmaniasis, tuberculosis, dengue fever and leprosy are present over almost the entire Brazilian territory. More than 90% of malaria cases occur in the Northern region of the country, and lymphatic filariasis and onchocerciasis occur in outbreaks in a particular region. The North and Northeast regions of Brazil have the lowest HDIs and the highest rates of NTDs. These diseases are considered neglected because there is not important investment in projects for the development of new drugs and vaccines and existing programs to control these diseases are not sufficient. Another problem related to NTDs is co-infection with HIV, which favors the occurrence of severe clinical manifestations and therapeutic failure. In this article, we describe the status of the main NTDs currently occurring in Brazil and relate them to the HDI and poverty.

Mosquitoes of the Caatinga: 2. Species from periodic sampling of bromeliads and tree holes in a dry Brazilian forest.

PubMed

Marteis, Letícia Silva; Natal, Delsio; Sallum, Maria Anice Mureb; Medeiros-Sousa, Antônio Ralph; Corte, Roseli La

2017-07-01

The Caatinga is a dry tropical forest, located in the Brazilian semiarid region and rich in phytotelmata. This study investigated the culicid fauna of phytotelmata of the caatinga by sampling for 19 consecutive months aquatic immatures from tree holes and bromeliads. A total of 127L of water was taken from the plants, containing 6764 immature culicids of 16 species, of which 11 (69%) are undescribed and respond to 90% of the total abundance of the specimens collected. Epiphytic bromeliads harbor a large number of immature Culicidae, although terrestrial bromeliads are the most abundant and widely distributed in the region. The richness of culicid species was similar between terrestrial and epiphytic bromeliads and lower in habitats represented by tree hole phytotelmata. There was no similarity in the composition of culicid species that developed in bromeliads or tree holes. Temperature and humidity were the environmental parameters most strongly associated with the proportion of positive plants. The Caatinga has a great number of endemic species that remain unknown to science and many additional culicid species may await discovery from there. Copyright © 2017 Elsevier B.V. All rights reserved.

The role of frugivorous bats in tropical forest succession.

PubMed

Muscarella, Robert; Fleming, Theodore H

2007-11-01

Discussion of successional change has traditionally focused on plants. The role of animals in producing and responding to successional change has received far less attention. Dispersal of plant propagules by animals is a fundamental part of successional change in the tropics. Here we review the role played by frugivorous bats in successional change in tropical forests. We explore the similarities and differences of this ecological service provided by New and Old World seed-dispersing bats and conclude with a discussion of their current economic and conservation implications. Our review suggests that frugivorous New World phyllostomid bats play a more important role in early plant succession than their Old World pteropodid counterparts. We propose that phyllostomid bats have shared a long evolutionary history with small-seeded early successional shrubs and treelets while pteropodid bats are principally dispersers of the seeds of later successional canopy fruits. When species of figs (Ficus) are involved in the early stages of primary succession (e.g. in the river meander system in Amazonia and on Krakatau, Indonesia), both groups of bats are important contributors of propagules. Because they disperse and sometimes pollinate canopy trees, pteropodid bats have a considerable impact on the economic value of Old World tropical forests; phyllostomid bats appear to make a more modest direct contribution to the economic value of New World tropical forests. Nonetheless, because they critically influence forest regeneration, phyllostomid bats make an important indirect contribution to the economic value of these forests. Overall, fruit-eating bats play important roles in forest regeneration throughout the tropics, making their conservation highly desirable.

CARBON SEQUESTRATION AND PLANT COMMUNITY DYNAMICS FOLLOWING REFORESTATION OF TROPICAL PASTURE.

Treesearch

WHENDEE L. SILVER; LARA M. KUEPPERS; ARIEL E. LUGO; REBECCA OSTERTAG; VIRGINIA MATZEK

2004-01-01

Conversion of abandoned cattle pastures to secondary forests and plantations in the tropics has been proposed as a means to increase rates of carbon (C) sequestration from the atmosphere and enhance local biodiversity. We used a long-term tropical reforestation project (55–61 yr) to estimate rates of above- and belowground C sequestration and to investigate the impact...

Congruent biogeographical disjunctions at a continent-wide scale: Quantifying and clarifying the role of biogeographic barriers in the Australian tropics.

PubMed

Edwards, Robert D; Crisp, Michael D; Cook, Dianne H; Cook, Lyn G

2017-01-01

To test whether novel and previously hypothesized biogeogaphic barriers in the Australian Tropics represent significant disjunction points or hard barriers, or both, to the distribution of plants. Australian tropics: Australian Monsoon Tropics and Australian Wet Tropics. The presence or absence of 6,861 plant species was scored across 13 putative biogeographic barriers in the Australian Tropics, including two that have not previously been recognised. Randomizations of these data were used to test whether more species showed disjunctions (gaps in distribution) or likely barriers (range limits) at these points than expected by chance. Two novel disjunctions in the Australian Tropics flora are identified in addition to eleven putative barriers previously recognized for animals. Of these, eleven disjunction points (all within the Australian Monsoon Tropics) were found to correspond to range-ending barriers to a significant number of species, while neither of the two disjunctions found within the Australian Wet Tropics limited a significant number of species' ranges. Biogeographic barriers present significant distributional limits to native plant species in the Australian Monsoon Tropics but not in the Australian Wet Tropics.

Coupled nutrient cycling determines tropical forest trajectory under elevated CO2.

NASA Astrophysics Data System (ADS)

Bouskill, N.; Zhu, Q.; Riley, W. J.

2017-12-01

Tropical forests have a disproportionate capacity to affect Earth's climate relative to their areal extent. Despite covering just 12 % of land surface, tropical forests account for 35 % of global net primary productivity and are among the most significant of terrestrial carbon stores. As atmospheric CO2 concentrations increase over the next century, the capacity of tropical forests to assimilate and sequester anthropogenic CO2 depends on limitation by multiple factors, including the availability of soil nutrients. Phosphorus availability has been considered to be the primary factor limiting metabolic processes within tropical forests. However, recent evidence points towards strong spatial and temporal co-limitation of tropical forests by both nitrogen and phosphorus. Here, we use the Accelerated Climate Modeling for Energy (ACME) Land Model (ALMv1-ECA-CNP) to examine how nutrient cycles interact and affect the trajectory of the tropical forest carbon sink under, (i) external nutrient input, (ii) climate (iii) elevated CO2, and (iv) a combination of 1-3. ALMv1 includes recent theoretical advances in representing belowground competition between roots, microbes and minerals for N and P uptake, explicit interactions between the nitrogen and phosphorus cycles (e.g., phosphatase production and nitrogen fixation), the dynamic internal allocation of plant N and P resources, and the integration of global datasets of plant physiological traits. We report nutrient fertilization (N, P, N+P) predictions for four sites in the tropics (El Verde, Puerto Rico, Barro Colorado Island, Panama, Manaus, Brazil and the Osa Peninsula, Coast Rica) to short-term nutrient fertilization (N, P, N+P), and benchmarking of the model against a meta-analysis of forest fertilization experiments. Subsequent simulations focus on the interaction of the carbon, nitrogen, and phosphorus cycles across the tropics with a focus on the implications of coupled nutrient cycling and the fate of the tropical

Contribution of seagrass plants to CO2 capture in a tropical seagrass meadow under experimental disturbance

PubMed Central

Gullström, Martin; Lyimo, Liberatus D.; Dahl, Martin; Hamisi, Mariam I.; Mtolera, Matern S. P.; Björk, Mats

2017-01-01

Coastal vegetative habitats are known to be highly productive environments with a high ability to capture and store carbon. During disturbance this important function could be compromised as plant photosynthetic capacity, biomass, and/or growth are reduced. To evaluate effects of disturbance on CO2 capture in plants we performed a five-month manipulative experiment in a tropical seagrass (Thalassia hemprichii) meadow exposed to two intensity levels of shading and simulated grazing. We assessed CO2 capture potential (as net CO2 fixation) using areal productivity calculated from continuous measurements of diel photosynthetic rates, and estimates of plant morphology, biomass and productivity/respiration (P/R) ratios (from the literature). To better understand the plant capacity to coping with level of disturbance we also measured plant growth and resource allocation. We observed substantial reductions in seagrass areal productivity, biomass, and leaf area that together resulted in a negative daily carbon balance in the two shading treatments as well as in the high-intensity simulated grazing treatment. Additionally, based on the concentrations of soluble carbohydrates and starch in the rhizomes, we found that the main reserve sources for plant growth were reduced in all treatments except for the low-intensity simulated grazing treatment. If permanent, these combined adverse effects will reduce the plants’ resilience and capacity to recover after disturbance. This might in turn have long-lasting and devastating effects on important ecosystem functions, including the carbon sequestration capacity of the seagrass system. PMID:28704565

No evidence that boron influences tree species distributions in lowland tropical forests of Panama.

PubMed

Turner, Benjamin L; Zalamea, Paul-Camilo; Condit, Richard; Winter, Klaus; Wright, S Joseph; Dalling, James W

2017-04-01

It was recently proposed that boron might be the most important nutrient structuring tree species distributions in tropical forests. Here we combine observational and experimental studies to test this hypothesis for lowland tropical forests of Panama. Plant-available boron is uniformly low in tropical forest soils of Panama and is not significantly associated with any of the > 500 species in a regional network of forest dynamics plots. Experimental manipulation of boron supply to seedlings of three tropical tree species revealed no evidence of boron deficiency or toxicity at concentrations likely to occur in tropical forest soils. Foliar boron did not correlate with soil boron along a local scale gradient of boron availability. Fifteen years of boron addition to a tropical forest increased plant-available boron by 70% but did not significantly change tree productivity or boron concentrations in live leaves, wood or leaf litter. The annual input of boron in rainfall accounts for a considerable proportion of the boron in annual litterfall and is similar to the pool of plant-available boron in the soil, and is therefore sufficient to preclude boron deficiency. We conclude that boron does not influence tree species distributions in Panama and presumably elsewhere in the lowland tropics. No claim to original US government works New Phytologist © 2016 New Phytologist Trust.

Rethinking plant functional types in Earth System Models: pan-tropical analysis of tree survival across environmental gradients

NASA Astrophysics Data System (ADS)

Johnson, D. J.; Needham, J.; Xu, C.; Davies, S. J.; Bunyavejchewin, S.; Giardina, C. P.; Condit, R.; Cordell, S.; Litton, C. M.; Hubbell, S.; Kassim, A. R. B.; Shawn, L. K. Y.; Nasardin, M. B.; Ong, P.; Ostertag, R.; Sack, L.; Tan, S. K. S.; Yap, S.; McDowell, N. G.; McMahon, S.

2016-12-01

Terrestrial carbon cycling is a function of the growth and survival of trees. Current model representations of tree growth and survival at a global scale rely on coarse plant functional traits that are parameterized very generally. In view of the large biodiversity in the tropical forests, it is important that we account for the functional diversity in order to better predict tropical forest responses to future climate changes. Several next generation Earth System Models are moving towards a size-structured, trait-based approach to modelling vegetation globally, but the challenge of which and how many traits are necessary to capture forest complexity remains. Additionally, the challenge of collecting sufficient trait data to describe the vast species richness of tropical forests is enormous. We propose a more fundamental approach to these problems by characterizing forests by their patterns of survival. We expect our approach to distill real-world tree survival into a reasonable number of functional types. Using 10 large-area tropical forest plots that span geographic, edaphic and climatic gradients, we model tree survival as a function of tree size for hundreds of species. We found surprisingly few categories of size-survival functions emerge. This indicates some fundamental strategies at play across diverse forests to constrain the range of possible size-survival functions. Initial cluster analysis indicates that four to eight functional forms are necessary to describe variation in size-survival relations. Temporal variation in size-survival functions can be related to local environmental variation, allowing us to parameterize how demographically similar groups of species respond to perturbations in the ecosystem. We believe this methodology will yield a synthetic approach to classifying forest systems that will greatly reduce uncertainty and complexity in global vegetation models.

Selection of sugar cane families by using BLUP and multi-diverse analyses for planting in the Brazilian savannah.

PubMed

Barbosa, M H P; Ferreira, A; Peixoto, L A; Resende, M D V; Nascimento, M; Silva, F F

2014-03-12

This study evaluated different strategies to select sugar cane families and obtain clones adapted to the conditions of the Brazilian savannah. Specifically, 7 experiments were conducted, with 10 full sib families, and 2 witnesses in common to all experiments, in each experiment. The plants were grown in random blocks, with witnesses in common (incomplete blocks), and 6 repetitions of each experiment. The data were analyzed through the methodology of mixed patterns, in which the matrices of kinship between the families were identified by the method of restricted maximum likelihood. The characteristics that were evaluated included soluble solids content (BRIX), BRIX ton/ha, average mass of a culm, number of culms/m, and tons of culms/ha. A multi-diverse alternative based on the analysis of groupings by using the UPGMA method was used to identify the most viable families for selection, when considering the genotypic effects on all characteristics. This method appeared suitable for the selection of families, with 5 family groups being formed. The families that formed Group 2 appeared superior to all other families for all the evaluated characteristics. It is recommended that the families in Group 2 are preferentially used in sugar cane improvement programs to obtain varieties optimally adapted to the conditions of the Brazilian savannah.

Germination, survival and growth of three vascular plants on biological soil crusts from a Mexican tropical desert.

PubMed

Godínez-Alvarez, H; Morín, C; Rivera-Aguilar, V

2012-01-01

Information about the effects of biological soil crusts (BSC) on germination, seedling survival and growth of vascular plants is controversial because they can have positive, neutral or negative effects. This controversy may be because most studies conducted until now have just analysed one or two recruitment stages independently. To understand the BSC effects on vascular plants, it is necessary to consider each stage of the recruitment process and synthesise all this information. The goal of this study was twofold. First, we analyse germination, seedling survival and growth of three vascular plants (Agave marmorata, Prosopis laevigata and Neobuxbaumia tetetzo) on BSC (cyanobacteria and mixed crust) from a tropical desert region of south-central México. Second, we synthesise the information to determine the total effect of BSC on plant species performance. We conducted experiments under controlled conditions to evaluate the proportion of germinated seeds, proportion of surviving seedlings and seedling dry weight in BSC and bare soil. Results showed that BSC have different effects on germination, seedling survival and growth of plant species. Plant species performance was qualitatively higher on BSC than bare soil. The highest performance of A. marmorata and P. laevigata was observed on cyanobacteria and mixed crusts, respectively. The highest performance of N. tetetzo was on both crust types. © 2011 German Botanical Society and The Royal Botanical Society of the Netherlands.

Soil Organic Matter Quality of an Oxisol Affected by Plant Residues and Crop Sequence under No-Tillage

NASA Astrophysics Data System (ADS)

Cora, Jose; Marcelo, Adolfo

2013-04-01

Plant residues are considered the primarily resource for soil organic matter (SOM) formation and the amounts and properties of plant litter are important controlling factors for the SOM quality. We determined the amounts, quality and decomposition rate of plant residues and the effects of summer and winter crop sequences on soil organic C (TOC) content, both particulate organic C (POC) and mineral-associated organic C (MOC) pools and humic substances in a Brazilian Rhodic Eutrudox soil under a no-tillage system. The organic C analysis in specifics pools used in this study was effective and should be adopted in tropical climates to evaluate the soil quality and the sustainability of various cropping systems. Continuous growth of soybean (Glycine max L. Merrill) on summer provided higher contents of soil POC and continuous growth of maize (Zea mays L.) provided higher soil humic acid and MOC contents. Summer soybean-maize rotation provided the higher plant diversity, which likely improved the soil microbial activity and the soil organic C consumption. The winter sunn hemp (Crotalaria juncea L.), pigeon pea (Cajanus cajan (L.) Millsp), oilseed radish (Raphanus sativus L.) and pearl millet (Pennisetum americanum (L.) Leeke) enhanced the soil MOC, a finding that is attributable to the higher N content of the crop residue. Sunn hemp and pigeon pea provided the higher soil POC content. Sunn hemp showed better performance and positive effects on the SOM quality, making it a suitable winter crop choice for tropical conditions with a warm and dry winter.

Tick fauna from two locations in the Brazilian savannah.

PubMed

Szabó, Matias Pablo Juan; Olegário, Maria Marlene Martins; Santos, André Luiz Quagliatto

2007-01-01

The Cerrado is Brazil's tropical savannah, which is arguably under greater threat than the Amazon rainforest. The Cerrado Biome of tropical South America covers about 2 million km(2) and is considered a biodiversity hot spot which means that it is especially rich in endemic species and particularly threatened by human activities. The Cerrado is increasingly exposed to agricultural activities which enhance the likelihood of mixing parasites from rural, urban and wildlife areas. Information about ticks from the Cerrado biome is scarce. In this report tick species free-living, on domestic animals and on a few wild animals in two farms in the Cerrado biome (Nova Crixás and Araguapaz municipalities, Goiás State, Brazil) are described. Amblyomma cajennense was the first and Amblyomma parvum the second host-seeking tick species found. Only two other tick species were found free-living: one Amblyomma nodosum and three Amblyomma naponense nymphs. Cattle were infested with Boophilus microplus and A. cajennense. Buffalos were infested with B. microplus and A. parvum. Dogs were infested with A. cajennense, Amblyomma ovale, A. parvum and Rhipicephalus sanguineus ticks. Anocentor nitens, B. microplus, A. cajennense, and A. parvum were found on horses. Amblyomma auricularium were found attached to nine-banded armadillos and Amblyomma rotundatum to red-footed tortoise, cururu toads and a rattlesnake. The latter was also infested with an adult A. cajennense. No tick was found on a goat, a tropical rat snake and a yellow armadillo. Among the observations the infestation of several domestic animals with A. parvum seems be the main feature. It suggests that this species might become a pest. However, the life cycle of A. parvum in nature, as well as its disease vectoring capacity, are largely unknown. It would be important to determine if it is a species expanding its geographic range by adaptation to new hosts or if it has been maintained in high numbers at definite locations by

Heavy-metal-contaminated industrial soil: Uptake assessment in native plant species from Brazilian Cerrado.

PubMed

Meyer, Sylvia Therese; Castro, Samuel Rodrigues; Fernandes, Marcus Manoel; Soares, Aylton Carlos; de Souza Freitas, Guilherme Augusto; Ribeiro, Edvan

2016-08-02

Plants of the Cerrado have shown some potential for restoration and/or phytoremediation projects due to their ability to grow in and tolerate acidic soils rich in metals. The aim of this study is to evaluate the tolerance and accumulation of metals (Cd, Cu, Pb, and Zn) in five native tree species of the Brazilian Cerrado (Copaifera langsdorffii, Eugenia dysenterica, Inga laurina, Cedrela fissilis, Handroanthus impetiginosus) subjected to three experiments with contaminated soils obtained from a zinc processing industry (S1, S2, S3) and control soil (S0). The experimental design was completely randomized (factorial 5 × 4 × 3) and conducted in a greenhouse environment during a 90-day experimentation time. The plant species behavior was assessed by visual symptoms of toxicity, tolerance index (TI), translocation factor (TF), and bioaccumulation factor (BF). C. fissilis has performed as a Zn accumulator by the higher BFs obtained in the experiments, equal to 3.72, 0.88, and 0.41 for S1, S2, and S3 respectively. This species had some ability of uptake control as a defense mechanism in high stress conditions with the best behavior for phytoremediation and high tolerance to contamination. With economical and technical benefits, this study may support a preliminary analysis necessary for using native tree species in environmental projects.

Do different degrees of human activity affect the diet of Brazilian silverside Atherinella brasiliensis?

PubMed

Alves, V E N; Patrício, J; Dolbeth, M; Pessanha, A; Palma, A R T; Dantas, E W; Vendel, A L

2016-08-01

The aim of the present study was to test whether different degrees of human activity affect the diet of the Brazilian silverside Atherinella brasiliensis in two tropical estuaries. Fish were collected along the salinity gradient of two Brazilian estuaries, the heavily impacted Paraiba Estuary and the less impacted Mamanguape Estuary, in the dry and wet seasons. The findings confirm that A. brasiliensis has generalist feeding habits and is able to change its diet under different environmental conditions. The results indicate clear spatial (i.e. along the estuarine gradient) changes in diet composition in both estuaries, but diet was also influenced by the degree of anthropogenic disturbance. During the wet season in the nutrient enriched Paraiba Estuary, when human activity was higher, the diet of A. brasiliensis was poorer and dominated by few dietary items, reflecting the potential impoverishment of prey items in this heavily disturbed system. The specimens collected in the most affected estuary also had a greater frequency of micro-plastics and parasites in their stomachs, reflecting the greater degree of human disturbance in the estuary. The present findings suggest that the diet of A. brasiliensis could be a useful indicator of changes in the ecological quality of these and other tropical estuaries of the western Atlantic Ocean. © 2016 The Fisheries Society of the British Isles.

Unexprected Changes in Soil Phosphorus Dynamics Following Tropical Deforestation to Cattle Pasture

NASA Technical Reports Server (NTRS)

Townsend, Alan R.; Asner, Gregory P.; Cleveland, Cory C.; Lefer, Margaret E.; Bustamante, Mercedes M. C.

2001-01-01

Phosphorus (P) is widely believed to limit plant growth and organic matter storage in a large fraction of the world's lowland tropical rainforests. We investigated how the most common land use change in such forests, conversion to cattle pasture, affects soil P fractions along forest to pasture chronosequences in the central Brazilian Amazon and in southwestern Costa Rica. Our sites represent a broad range in rainfall, soil type, management strategies, and total soil P (45.2 - 1228.0 microng P / g soil), yet we found some unexpected and at times strikingly similar changes in soil P in all sites. In the Brazilian sites, where rainfall is relatively low and pasture management is more intense than in the Costa Rican sites, significant losses in total soil P and soil organic carbon (SOC) were seen with pasture age on both fine-textured oxisol and highly sandy entisol soils. However, P losses were largely from occluded, inorganic soil P fractions, while organic forms of soil P remained constant or increased with pasture age, despite the declines in SOC. In Costa Rica, SOC remained constant across the oxisol sites and increased from forest to pasture on the mollisols, while total soil P increased with pasture age in both sequences. The increases in total soil P were largely due to changes in organic P; occluded soil P increased only slightly in the mollisols, and remained unchanged in the older oxisols. We suggest that changes in the composition and/or the primary limiting resources of the soil microbial community may drive the changes in organic P. We also present a new conceptual model for changes in soil P following deforestation to cattle pasture.

Polychlorinated biphenyls and polybrominated diphenylethers in soils from planted forests and adjacent natural forests on a tropical island.

PubMed

Liu, Xin; Wang, Shuai; Jiang, Yishan; Sun, Yingtao; Li, Jun; Zhang, Gan

2017-08-01

Transformation from natural forests to planted forests in tropical regions is an expanding global phenomenon causing major modifications of land cover and soil properties, e.g. soil organic carbon (SOC). This study investigated accumulations of POPs in soils under eucalyptus and rubber forests as compared with adjacent natural forests on Hainan Island, China. Results showed that due to the greater forest filter effect and the higher SOC, the natural forest have accumulated larger amounts of POPs in the top 20 cm soil. Based on correlation and air-soil equilibrium analysis, we highlighted the importance of SOC in the distribution of POPs. It is assumed that the elevated mobility of POPs in the planted forests was caused by greater loss of SOC and extensive leaching in the soil profile. This suggests that a better understanding of global POPs fate should take into consideration the role of planted forests. Copyright © 2017 Elsevier Ltd. All rights reserved.

Phosphorus migration analysis using synchrotron radiation in soil treated with Brazilian granular fertilizers.

PubMed

de Castro, Robson C; de Melo Benites, Vinícius; César Teixeira, Paulo; Dos Anjos, Marcelino José; de Oliveira, Luis Fernando

2015-11-01

The aim of this study was to evaluate the phosphorus (P) mobility in a tropical Brazilian soil type red Oxisol treated with three different forms of granular fertilizer. Total Reflection X-Ray Fluorescence (TXRF) was applied to determine the concentration of P at different distances from granular fertilizer application point. The results showed that most of the P from fertilizers tends to concentrate in a region of up to 10mm around the place of the fertilizer deposition. Copyright © 2015. Published by Elsevier Ltd.

Towards restoration of Hawaiian tropical dry forests: the Kaupulehu outplanting programme

Treesearch

Susan Cordell; Moana McClellan; Yvonne Yarber Carter; Lisa J. Hadway

2008-01-01

Hawaiian tropical dry forests contain diverse assemblages of woody canopy species, including many endemic and endangered species that warrant conservation attention before completely disappearing. Today, tropical dry forests in Hawaii are not viable ecosystems. Poor land use practices, fragmentation, non-native plant invasions, and inadequate native vegetation...

Congruent biogeographical disjunctions at a continent-wide scale: Quantifying and clarifying the role of biogeographic barriers in the Australian tropics

PubMed Central

Crisp, Michael D.; Cook, Dianne H.; Cook, Lyn G.

2017-01-01

Aim To test whether novel and previously hypothesized biogeogaphic barriers in the Australian Tropics represent significant disjunction points or hard barriers, or both, to the distribution of plants. Location Australian tropics: Australian Monsoon Tropics and Australian Wet Tropics. Methods The presence or absence of 6,861 plant species was scored across 13 putative biogeographic barriers in the Australian Tropics, including two that have not previously been recognised. Randomizations of these data were used to test whether more species showed disjunctions (gaps in distribution) or likely barriers (range limits) at these points than expected by chance. Results Two novel disjunctions in the Australian Tropics flora are identified in addition to eleven putative barriers previously recognized for animals. Of these, eleven disjunction points (all within the Australian Monsoon Tropics) were found to correspond to range-ending barriers to a significant number of species, while neither of the two disjunctions found within the Australian Wet Tropics limited a significant number of species’ ranges. Main conclusions Biogeographic barriers present significant distributional limits to native plant species in the Australian Monsoon Tropics but not in the Australian Wet Tropics. PMID:28376094

Engineered ecosystem for on-site wastewater treatment in tropical areas.

PubMed

de Sá Salomão, André Luis; Marques, Marcia; Severo, Raul Gonçalves; da Cruz Roque, Odir Clécio

2012-01-01

There is a worldwide demand for decentralized wastewater treatment options. An on-site engineered ecosystem (EE) treatment plant was designed with a multistage approach for small wastewater generators in tropical areas. The array of treatment units included a septic tank, a submersed aerated filter, and a secondary decanter followed by three vegetated tanks containing aquatic macrophytes intercalated with one tank of algae. During 11 months of operation with a flow rate of 52 L h(-1), the system removed on average 93.2% and 92.9% of the chemical oxygen demand (COD) and volatile suspended solids (VSS) reaching final concentrations of 36.3 ± 12.7 and 13.7 ± 4.2 mg L(-1), respectively. Regarding ammonia-N (NH(4)-N) and total phosphorus (TP), the system removed on average 69.8% and 54.5% with final concentrations of 18.8 ± 9.3 and 14.0 ± 2.5 mg L(-1), respectively. The tanks with algae and macrophytes together contributed to the overall nutrient removal with 33.6% for NH(4)-N and 26.4% for TP. The final concentrations for all parameters except TP met the discharge threshold limits established by Brazilian and EU legislation. The EE was considered appropriate for the purpose for which it was created.

Sorption of thiabendazole in sub-tropical Brazilian soils.

PubMed

de Oliveira Neto, Odilon França; Arenas, Alejandro Yopasa; Fostier, Anne Hélène

2017-07-01

Thiabendazole (TBZ) is an ionizable anthelmintic agent that belongs to the class of benzimidazoles. It is widely used in veterinary medicine and as a fungicide in agriculture. Sorption and desorption are important processes influencing transport, transformation, and bioavailability of xenobiotic compounds in soils; data related to sorption capacity are therefore needed for environmental risk assessments. The aim of this work was to assess the sorption potential of TBZ in four Brazilians soils (sandy, sandy-clay, and clay soils), using batch equilibrium experiments at three pH ranges (2.3-3.0, 3.8-4.2, and 5.5-5.7). The Freundlich sorption coefficient (K F ) ranged from 9.0 to 58 μg 1-1/n  (mL) 1/n  g -1 , with higher values generally observed at the lower pH ranges (2.3-3.0 and 3.8-4.2) and for clay soils. The highest organic carbon-normalized sorption coefficients (K OC ) obtained at pH 3.8-5.7 (around the natural pH range of 4.1-5.0) for both clay soils and sandy-clay soil were 3255 and 2015 mL g -1 , respectively. The highest correlations K F vs SOM (r = 0.70) and K F vs clay content (r = 0.91) were observed at pH 3.8-4.2. Our results suggest that TBZ sorption/desorption is strongly pH dependent and that its mobility could be higher in the studied soils than previously reported in soils from temperate regions.

Alien and endangered plants in the Brazilian Cerrado exhibit contrasting relationships with vegetation biomass and N : P stoichiometry.

PubMed

Lannes, Luciola S; Bustamante, Mercedes M C; Edwards, Peter J; Venterink, Harry Olde

2012-11-01

Although endangered and alien invasive plants are commonly assumed to persist under different environmental conditions, surprisingly few studies have investigated whether this is the case. We examined how endangered and alien species are distributed in relation to community biomass and N : P ratio in the above-ground community biomass in savanna vegetation in the Brazilian Cerrado. For 60 plots, we related the occurrence of endangered (Red List) and alien invasive species to plant species richness, vegetation biomass and N : P ratio, and soil variables. Endangered plants occurred mainly in plots with relatively low above-ground biomass and high N : P ratios, whereas alien invasive species occurred in plots with intermediate to high biomass and low N : P ratios. Occurrences of endangered or alien plants were unrelated to extractable N and P concentrations in the soil. These contrasting distributions in the Cerrado imply that alien species only pose a threat to endangered species if they are able to invade sites occupied by these species and increase the above-ground biomass and/or decrease the N : P ratio of the vegetation. We found some evidence that alien species do increase above-ground community biomass in the Cerrado, but their possible effect on N : P stoichiometry requires further study. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

Diversity in plant hydraulic traits explains seasonal and inter-annual variations of vegetation dynamics in seasonally dry tropical forests.

PubMed

Xu, Xiangtao; Medvigy, David; Powers, Jennifer S; Becknell, Justin M; Guan, Kaiyu

2016-10-01

We assessed whether diversity in plant hydraulic traits can explain the observed diversity in plant responses to water stress in seasonally dry tropical forests (SDTFs). The Ecosystem Demography model 2 (ED2) was updated with a trait-driven mechanistic plant hydraulic module, as well as novel drought-phenology and plant water stress schemes. Four plant functional types were parameterized on the basis of meta-analysis of plant hydraulic traits. Simulations from both the original and the updated ED2 were evaluated against 5 yr of field data from a Costa Rican SDTF site and remote-sensing data over Central America. The updated model generated realistic plant hydraulic dynamics, such as leaf water potential and stem sap flow. Compared with the original ED2, predictions from our novel trait-driven model matched better with observed growth, phenology and their variations among functional groups. Most notably, the original ED2 produced unrealistically small leaf area index (LAI) and underestimated cumulative leaf litter. Both of these biases were corrected by the updated model. The updated model was also better able to simulate spatial patterns of LAI dynamics in Central America. Plant hydraulic traits are intercorrelated in SDTFs. Mechanistic incorporation of plant hydraulic traits is necessary for the simulation of spatiotemporal patterns of vegetation dynamics in SDTFs in vegetation models. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Lidar-based multinomial classification algorithms for tropical forest degradation status: Implications for biomass estimation

NASA Astrophysics Data System (ADS)

Duffy, P.; Keller, M.; Longo, M.; Morton, D. C.; dos-Santos, M. N.; Pinagé, E. R.

2017-12-01

There is an urgent need to quantify the effects of land use and land cover change on carbon stocks in tropical forests to support REDD+ policies and improve characterization of global carbon budgets. This need is underscored by the fact that the variability in forest biomass estimates from global forest carbon maps is artificially low relative to estimates generated from forest inventory and high-resolution airborne lidar data. Both deforestation and degradation processes (e.g. logging, fire, and fragmentation) affect carbon fluxes at varying spatial and temporal scales. While the spatial extent and impact of deforestation has been relatively well characterized, the quantification of degradation processes is still poorly constrained. In the Brazilian Amazon, the largest source of uncertainty in CO2 emissions estimates is data on changes in tropical forest carbon stocks through time, followed closely by incomplete information on the carbon losses from forest degradation. In this work, we present a method for classifying the degradation status of tropical forests using higher order moments (skewness and kurtosis) of lidar return distributions aggregated at grids with resolution ranging from 50 m to 250 m. Across multiple spatial resolutions, we quantify the strength of the functional relationship between the lidar returns and the classification based on historical time series of Landsat imagery. Our results show that the higher order moments of the lidar return distributions provide sufficient information to build multinomial models that accurately classify the landscape into intact, logged, and burned forests. Model fit improved with coarser spatial resolution with Kappa statistics of 0.70 at 50 m, and 0.77 at 250 m. In addition, multi-class AUC was estimated as 0.87 at 50 m, and 0.95 at 250 m. This classification provides important information regarding the applicability of the use of lidar data for regional monitoring of recent logging, as well as the trajectory

Plant available nitrogen from anaerobically digested sludge and septic tank sludge applied to crops grown in the tropics.

PubMed

Sripanomtanakorn, S; Polprasert, C

2002-04-01

Agricultural land is an attractive alternative for the disposal of biosolids since it utilises the recyclable nutrients in the production of crops. In Thailand and other tropical regions, limited field-study information exists on the effect of biosolids management strategies on crop N utilisation and plant available N (PAN) of biosolids. A field study was conducted to quantify the PAN of the applied biosolids, and to evaluate the N uptake rates of some tropical crops. Sunflower (Helianthus annuus) and tomato (Lycopersicon esculentum) were chosen in this study. Two types of biosolids used were: anaerobically digested sludge and septic tank sludge. The soil is acid sulfate and is classified as Sulfic Tropaquepts with heavy clay in texture. The anaerobically digested sludge applied rates were: 0, 156 and 312 kg N ha(-1) for the sunflower plots, and 0, 586, and 1172 kg N ha(-1) for the tomato plots. The septic tank sludge applied rates were: 0, 95 and 190 kg N ha(-1) for the sunflower plots, and 0, 354 and 708 kg N ha(-1) for the tomato plots, respectively. The results indicated the feasibility of applying biosolids to grow tropical crops. The applications of the anaerobically digested sludge and the septic tank sludge resulted in the yields of sunflower seeds and tomato fruits and the plant N uptakes comparable or better than that applied with only the chemical fertiliser. The estimated PAN of the anaerobically digested sludge was about 27-42% of the sludge organic N during the growing season. For the septic tank sludge, the PAN was about 15-58% of the sludge organic N. It is interesting to observe that an increase of the rate of septic tank sludge incorporated into this heavy clay soil under the cropping system resulted in the decrease of N mineralisation rate. This situation could cause the reduction of yield and N uptake of crops.

Terrestrial Plant Biomarkers Preserved in Cariaco Basin Sediments: Records of Abrupt Tropical Vegetation Response to Rapid Climate Changes

NASA Astrophysics Data System (ADS)

Hughen, K. A.; Eglinton, T. I.; Makou, M.; Xu, L.; Sylva, S.

2004-12-01

Organic-rich sediments from the anoxic Cariaco Basin, Venezuela, preserve high concentrations of biomarkers for reconstruction of terrestrial environmental conditions. Molecular-level investigations of organic compounds provide a valuable tool for extracting terrestrial signals from these annually laminated marine sediments. Differences in hydrogen isotopic fractionation between C16-18 and C24-30 n-alkanoic acids suggest a marine source for the shorter chain lengths and a terrestrial source for the longer chains. Records of carbon and hydrogen isotopes, as well as average carbon chain length (ACL), from long-chain n-alkanoic acids parallel millennial-scale changes in vegetation and climate between the late Glacial and Preboreal periods, 15,000 to 10,000 years ago. Data from all terrestrial chain lengths were combined to produce single δ D and δ 13C indices through deglaciation, exhibiting enrichment during the late Glacial and Younger Dryas and depletion during the Bolling-Allerod and Preboreal periods. δ D reflects the hydrogen isotopic composition of environmental water used for plant growth, combined with evaporative enrichment within leaf spaces, and as such may act as a proxy for local aridity. Leaf wax δ 13C, which is a proxy for C3 versus C4 metabolic pathways, indicates that C3 plants predominated in the Cariaco watershed during warm/wet Bolling-Allerod and Holocene periods, and C4 plant biomass proliferated during cool/dry Glacial and Younger Dryas intervals. Coupled carbon and hydrogen isotopic measurements together clearly distinguish deglacial climatic periods as wetter with C3 vegetation versus drier with C4 vegetation. High resolution biomarker records reveal the rapidity of vegetation changes in northern South America during the last deglaciation. The leaf wax data reveal that local vegetation biomass, although not necessarily entire assemblages, shifted between arid grassland and wetter forest taxa on timescales of decades. Comparison of ACL

Pests vs. drought as determinants of plant distribution along a tropical rainfall gradient.

PubMed

Brenes-Arguedas, Tania; Coley, Phyllis D; Kursar, Thomas A

2009-07-01

Understanding the mechanisms that shape the distribution of organisms can help explain patterns of local and regional biodiversity and predict the susceptibility of communities to environmental change. In the species-rich tropics, a gradient in rainfall between wet evergreen and dry seasonal forests correlates with turnover of plant species. The strength of the dry season has previously been shown to correlate with species composition. Herbivores and pathogens (pests) have also been hypothesized to be important drivers of plant distribution, although empirical evidence is lacking. In this study we experimentally tested the existence of a gradient in pest pressure across a rainfall gradient in the Isthmus of Panama and measured the influence of pests relative to drought on species turnover. We established two common gardens on the dry and wet sides of the Isthmus using seedlings from 24 plant species with contrasting distributions along the Isthmus. By experimentally manipulating water availability and insect herbivore access, we showed that pests are not as strong a determinant of plant distributions as is seasonal drought. Seasonal drought in the dry site excluded wet-distribution species by significantly increasing their seedling mortality. Pathogen mortality and insect herbivore damage were both higher in the wet site, supporting the existence of a gradient in pest pressure. However, contrary to predictions, we found little evidence that dry-distribution species suffered significantly more pest attack than wet-distribution species. Instead, we hypothesize that dry-distribution species are limited from colonizing wetter forests by their inherently slower growth rates imposed by drought adaptations. We conclude that mechanisms limiting the recruitment of dry-distribution species in wet forests are not nearly as strong as those limiting wet-distribution species from dry forests.

Simplicity and Innovation Make This "Green" Brazilian City Work.

ERIC Educational Resources Information Center

Goodstein, Carol

1993-01-01

Describes how a Brazilian city, Curitiba, is successfully curbing environmental degradation through recycling efforts, transportation, housing, and land use changes. These projects include tree planting, decreased automobile use, a simple technology that enables buses to run as quickly and efficiently as subways, and increasing city open space…

Ethnomedicinal and ecological status of plants in Garhwal Himalaya, India

PubMed Central

2011-01-01

Background The northern part of India harbours a great diversity of medicinal plants due to its distinct geography and ecological marginal conditions. The traditional medical systems of northern India are part of a time tested culture and honored still by people today. These traditional systems have been curing complex disease for more than 3,000 years. With rapidly growing demand for these medicinal plants, most of the plant populations have been depleted, indicating a lack of ecological knowledge among communities using the plants. Thus, an attempt was made in this study to focus on the ecological status of ethnomedicinal plants, to determine their availability in the growing sites, and to inform the communities about the sustainable exploitation of medicinal plants in the wild. Methods The ecological information regarding ethnomedicinal plants was collected in three different climatic regions (tropical, sub-tropical and temperate) for species composition in different forest layers. The ecological information was assessed using the quadrate sampling method. A total of 25 quadrats, 10 × 10 m were laid out at random in order to sample trees and shrubs, and 40 quadrats of 1 × 1 m for herbaceous plants. In each climatic region, three vegetation sites were selected for ecological information; the mean values of density, basal cover, and the importance value index from all sites of each region were used to interpret the final data. Ethnomedicinal uses were collected from informants of adjacent villages. About 10% of inhabitants (older, experienced men and women) were interviewed about their use of medicinal plants. A consensus analysis of medicinal plant use between the different populations was conducted. Results Across the different climatic regions a total of 57 species of plants were reported: 14 tree species, 10 shrub species, and 33 herb species. In the tropical and sub-tropical regions, Acacia catechu was the dominant tree while Ougeinia oojeinensis in the

New species and new behavioral data of Phlugiola Karny, 1907 (Orthoptera: Tettigoniidae: Meconematinae) from the Brazilian Amazonian Rainforest.

PubMed

Mendes, Diego Matheus DE Mello; Oliveira, Jomara Cavalcante DE; Alves-Oliveira, João Rafael; Rafael, José Albertino

2017-03-16

Phlugiola Karny, 1907 is a genus of small predatory katydids with six included species distributed in Brazil, Bolivia, Colombia, Peru and Suriname. In this paper two new Brazilian species are described, Phlugiola longipedes sp. nov. (type locality: Amazonas, Tefé) and Phlugiola igarape sp. nov., (type locality: Acre, Bujari) both from tropical rainforests. Behavioral data and natural history notes are provided.

Ant diversity in Brazilian tropical dry forests across multiple vegetation domains

NASA Astrophysics Data System (ADS)

Figueiredo Silva, Luciana; Mello Souza, Rayana; Solar, Ricardo R. C.; de Siqueira Neves, Frederico

2017-03-01

Understanding the environmental drivers of biodiversity persistence and community organization in natural ecosystems is of great importance for planning the conservation of those ecosystems. This comprehension is even more important in severely threatened ecosystems. In this context, we analyzed ant communities in tropical dry forests (TDFs) in Brazil. These forests are embedded within other biomes, such as Cerrado and Caatinga. In this study, we asked whether (i) ant species richness and composition changes between TDFs within different vegetation domains; (ii) whether ant species richness and β-diversity increase north-to-south, possibly related to changes in tree richness and tree density; and (iii) species replacement contributes relatively more to β-diversity than does nestedness. We found that species composition is unique to each TDF within different biomes, and that species richness and β-diversity differ among the vegetation domains, being smaller in the Caatinga. We also found that replacement contributes most to β-diversity, although this contribution is lower in Caatinga than in Cerrado. We show that regional context is the main driver of species diversity, which is likely to be driven by both historical and ecological mechanisms. By analyzing large spatial scale variation in TDF environmental characteristics, we were able to evaluate how ant diversity changes along an environmental gradient. The high levels of species replacement and unique species composition of each region indicates that, to fully conserve TDFs, we need to have various conservation areas distributed across the entire range of vegetation domains in which these forests can be found. Thus, we demonstrate that a landscape-wise planning is urgent and necessary in order to preserve tropical dry forests.

Nitrogen to phosphorus ratio of plant biomass versus soil solution in a tropical pioneer tree, Ficus insipida.

PubMed

Garrish, Valerie; Cernusak, Lucas A; Winter, Klaus; Turner, Benjamin L

2010-08-01

It is commonly assumed that the nitrogen to phosphorus (N:P) ratio of a terrestrial plant reflects the relative availability of N and P in the soil in which the plant grows. Here, this was assessed for a tropical pioneer tree, Ficus insipida. Seedlings were grown in sand and irrigated with nutrient solutions containing N:P ratios ranging from <1 to >100. The experimental design further allowed investigation of physiological responses to N and P availability. Homeostatic control over N:P ratios was stronger in leaves than in stems or roots, suggesting that N:P ratios of stems and roots are more sensitive indicators of the relative availability of N and P at a site than N:P ratios of leaves. The leaf N:P ratio at which the largest plant dry mass and highest photosynthetic rates were achieved was approximately 11, whereas the corresponding whole-plant N:P ratio was approximately 6. Plant P concentration varied as a function of transpiration rate at constant nutrient solution P concentration, possibly due to transpiration-induced variation in the mass flow of P to root surfaces. The transpiration rate varied in response to nutrient solution N concentration, but not to nutrient solution P concentration, demonstrating nutritional control over transpiration by N but not P. Water-use efficiency varied as a function of N availability, but not as a function of P availability.

New strategies for drug discovery in tropical forests based on ethnobotanical and chemical ecological studies.

PubMed

Albuquerque, Ulysses Paulino; Ramos, Marcelo Alves; Melo, Joabe Gomes

2012-03-06

Hypotheses from ethnobotany and chemical ecology can increase our ability to predict the pharmaceutical potential of tropical flora. In order to illustrate how bioprospecting studies can benefit from the incorporation of these hypotheses, especially in tropical dry forests, we discuss evidence from ethnobotanical studies that examine hypotheses about the ecology of plant defense against herbivory. We focus on two hypotheses regarding defense patterns in plants-the plant apparency hypothesis and the resource availability hypothesis-and analyze how these can help us understand the use of medicinal plants by traditional communities. The evidence suggests that medicinal plants in the dry forest are a rich source of drugs in which phenolic compounds, especially tannins, are directly responsible for the therapeutic activity. Phenolic compounds and their potential therapeutic activity are likely good candidates for bioprospecting efforts. We believe that following strategies to link ethnobotanical and chemical ecological approaches will increase the efficiency of bioprospecting studies in tropical forests. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Tropical flowering phenologies

NASA Astrophysics Data System (ADS)

Wright, S. J.

2016-12-01

Most tropical plants flower synchronously at species-specific times. This holds at the geographic equator where day length is constant and at the meteorological equator where temperature is virtually aseasonal. Thus, the well-studied environmental cues for flowering at higher latitudes can be irrelevant in the tropics where they are replaced by an abundance of hypotheses. Low and high temperatures, drought and rain, day length, daily solar irradiance, and seasonal changes in solar insolation at the forest canopy or at the top of the atmosphere have all been hypothesized to act as environmental cues for tropical flowering. This abundance of hypotheses has been confronted by a paucity of data, precluding rejection of even one hypothesis. I will use new long-term data sets from Barro Colorado Island (BCI), Panama (9°N, 79°W) and a model selection framework to begin the winnowing. The data extend from 1987 to the present and include more than 250,000 flower records obtained in 1,515 weekly censuses of 200 passive traps and standard meteorological variables obtained just above the forest canopy. The model selection framework was used to evaluate every proximate cue hypothesized to control tropical flowering times for the 55 tree and liana species best represented in the data. Hypotheses concerning seasonal variation in day length, temperature, rainfall and photosynthetically active radiation (PAR) best matched the data for five, zero, seven and 32 species, respectively. Many species previously believed to respond to seasonal changes in moisture availability are actually sensitive to seasonal variation in cloud cover and PAR. BCI lies on the meteorological equator, thus it is unsurprising that temperature variation is not a viable proximate cue. The flowering phenology of the remaining 11 species could not be explained by any of the hypothesized proximate cues. Solutions to the environmental control of tropical flowering times remain to be discovered.

CO2 and fire influence tropical ecosystem stability in response to climate change.

PubMed

Shanahan, Timothy M; Hughen, Konrad A; McKay, Nicholas P; Overpeck, Jonathan T; Scholz, Christopher A; Gosling, William D; Miller, Charlotte S; Peck, John A; King, John W; Heil, Clifford W

2016-07-18

Interactions between climate, fire and CO2 are believed to play a crucial role in controlling the distributions of tropical woodlands and savannas, but our understanding of these processes is limited by the paucity of data from undisturbed tropical ecosystems. Here we use a 28,000-year integrated record of vegetation, climate and fire from West Africa to examine the role of these interactions on tropical ecosystem stability. We find that increased aridity between 28-15 kyr B.P. led to the widespread expansion of tropical grasslands, but that frequent fires and low CO2 played a crucial role in stabilizing these ecosystems, even as humidity changed. This resulted in an unstable ecosystem state, which transitioned abruptly from grassland to woodlands as gradual changes in CO2 and fire shifted the balance in favor of woody plants. Since then, high atmospheric CO2 has stabilized tropical forests by promoting woody plant growth, despite increased aridity. Our results indicate that the interactions between climate, CO2 and fire can make tropical ecosystems more resilient to change, but that these systems are dynamically unstable and potentially susceptible to abrupt shifts between woodland and grassland dominated states in the future.

CO2 and fire influence tropical ecosystem stability in response to climate change

NASA Astrophysics Data System (ADS)

Shanahan, Timothy M.; Hughen, Konrad A.; McKay, Nicholas P.; Overpeck, Jonathan T.; Scholz, Christopher A.; Gosling, William D.; Miller, Charlotte S.; Peck, John A.; King, John W.; Heil, Clifford W.

2016-07-01

Interactions between climate, fire and CO2 are believed to play a crucial role in controlling the distributions of tropical woodlands and savannas, but our understanding of these processes is limited by the paucity of data from undisturbed tropical ecosystems. Here we use a 28,000-year integrated record of vegetation, climate and fire from West Africa to examine the role of these interactions on tropical ecosystem stability. We find that increased aridity between 28-15 kyr B.P. led to the widespread expansion of tropical grasslands, but that frequent fires and low CO2 played a crucial role in stabilizing these ecosystems, even as humidity changed. This resulted in an unstable ecosystem state, which transitioned abruptly from grassland to woodlands as gradual changes in CO2 and fire shifted the balance in favor of woody plants. Since then, high atmospheric CO2 has stabilized tropical forests by promoting woody plant growth, despite increased aridity. Our results indicate that the interactions between climate, CO2 and fire can make tropical ecosystems more resilient to change, but that these systems are dynamically unstable and potentially susceptible to abrupt shifts between woodland and grassland dominated states in the future.

Leaf surface traits and water storage retention affect photosynthetic responses to leaf surface wetness among wet tropical forest and semiarid savanna plants.

PubMed

Aparecido, Luiza M T; Miller, Gretchen R; Cahill, Anthony T; Moore, Georgianne W

2017-10-01

While it is reasonable to predict that photosynthetic rates are inhibited while leaves are wet, leaf gas exchange measurements during wet conditions are challenging to obtain due to equipment limitations and the complexity of canopy-atmosphere interactions in forested environments. Thus, the objective of this study was to evaluate responses of seven tropical and three semiarid savanna plant species to simulated leaf wetness and test the hypotheses that (i) leaf wetness reduces photosynthetic rates (Anet), (ii) leaf traits explain different responses among species and (iii) leaves from wet environments are better adapted for wet leaf conditions than those from drier environments. The two sites were a tropical rainforest in northern Costa Rica with ~4200 mm annual rainfall and a savanna in central Texas with ~1100 mm. Gas exchange measurements were collected under dry and wet conditions on five sun-exposed leaf replicates from each species. Additional measurements included leaf wetness duration and stomatal density. We found that Anet responses varied greatly among species, but all plants maintained a baseline of activity under wet leaf conditions, suggesting that abaxial leaf Anet was a significant percentage of total leaf Anet for amphistomatous species. Among tropical species, Anet responses immediately after wetting ranged from -31% (Senna alata (L.) Roxb.) to +21% (Zamia skinneri Warsz. Ex. A. Dietr.), while all savanna species declined (up to -48%). After 10 min of drying, most species recovered Anet towards the observed status prior to wetting or surpassed it, with the exception of Quercus stellata Wangenh., a savanna species, which remained 13% below Anet dry. The combination of leaf wetness duration and leaf traits, such as stomatal density, trichomes or wax, most likely influenced Anet responses positively or negatively. There was also overlap between leaf traits and Anet responses of savanna and tropical plants. It is possible that these species converge

Fusarium-induced diseases of tropical, perennial crops.

PubMed

Ploetz, Randy C

2006-06-01

ABSTRACT The world's oldest ecosystems are found in the tropics. They are diverse, highly evolved, but barely understood. This and subsequent papers describe diseases of tropical, perennial plants that are caused by Fusarium spp. Many of these are economically significant, difficult to manage, and of scientific interest. Some represent coevolved patho-systems (e.g., Panama disease, tracheomycosis of coffee, fusariosis of pineapple, and Fusarium wilt of oil palm), whereas others may be new-encounter diseases or are caused by generalist pathogens (cushion gall of cacao). New vector relationships are evident in other pathosystems (e.g., mango malformation), and two or more pathogens have been shown to cause some of the diseases (Panama disease and tracheomycosis of coffee). More work on these pathosystems is warranted as they could reveal much about the evolution of plant pathogens and the important diseases they cause.

Microbial Food-Web Drivers in Tropical Reservoirs.

PubMed

Domingues, Carolina Davila; da Silva, Lucia Helena Sampaio; Rangel, Luciana Machado; de Magalhães, Leonardo; de Melo Rocha, Adriana; Lobão, Lúcia Meirelles; Paiva, Rafael; Roland, Fábio; Sarmento, Hugo

2017-04-01

Element cycling in aquatic systems is driven chiefly by planktonic processes, and the structure of the planktonic food web determines the efficiency of carbon transfer through trophic levels. However, few studies have comprehensively evaluated all planktonic food-web components in tropical regions. The aim of this study was to unravel the top-down controls (metazooplankton community structure), bottom-up controls (resource availability), and hydrologic (water residence time) and physical (temperature) variables that affect different components of the microbial food web (MFW) carbon stock in tropical reservoirs, through structural equation models (SEM). We conducted a field study in four deep Brazilian reservoirs (Balbina, Tucuruí, Três Marias, and Funil) with different trophic states (oligo-, meso-, and eutrophic). We found evidence of a high contribution of the MFW (up to 50% of total planktonic carbon), especially in the less-eutrophic reservoirs (Balbina and Tucuruí). Bottom-up and top-down effects assessed through SEM indicated negative interactions between soluble reactive phosphorus and phototrophic picoplankton (PPP), dissolved inorganic nitrogen, and heterotrophic nanoflagellates (HNF). Copepods positively affected ciliates, and cladocerans positively affected heterotrophic bacteria (HB) and PPP. Higher copepod/cladoceran ratios and an indirect positive effect of copepods on HB might strengthen HB-HNF coupling. We also found low values for the degree of uncoupling (D) and a low HNF/HB ratio compared with literature data (mostly from temperate regions). This study demonstrates the importance of evaluating the whole size spectrum (including microbial compartments) of the different planktonic compartments, in order to capture the complex carbon dynamics of tropical aquatic ecosystems.

Phylogenetic impoverishment of plant communities following chronic human disturbances in the Brazilian Caatinga.

PubMed

Ribeiro, Elâine M S; Santos, Bráulio A; Arroyo-Rodríguez, Víctor; Tabarelli, Marcelo; Souza, Gustavo; Leal, Inara R

2016-06-01

Chronic disturbances, such as selective logging, firewood extraction and extensive grazing, may lead to the taxonomic and phylogenetic impoverishment of remaining old-growth forest communities worldwide; however, the empirical evidence on this topic is limited. We tested this hypothesis in the Caatinga vegetation--a seasonally dry tropical forest restricted to northeast Brazil. We sampled 11,653 individuals (adults, saplings, and seedlings) from 51 species in 29 plots distributed along a gradient of chronic disturbance. The gradient was assessed using a chronic disturbance index (CDI) based on five recognized indicators of chronic disturbances: proximity to urban center, houses and roads and the density of both people and livestock. We used linear models to test if mean effective number of lineages, mean phylogenetic distance and phylogenetic dispersion decreased with CDI and if such relationships differed among ontogenetic stages. As expected, the mean effective number of lineages and the mean phylogenetic distance were negatively related to CDI, and such diversity losses occurred irrespective of ontogeny. Yet the increase in phylogenetic clustering in more disturbed plots was only evident in seedlings and saplings, mostly because clades with more descendent taxa than expected by chance (e.g., Euphorbiaceae) thrived in more disturbed plots. This novel study indicates that chronic human disturbances are promoting the phylogenetic impoverishment of the irreplaceable woody flora of the Brazilian Caatinga forest. The highest impoverishment was observed in seedlings and saplings, indicating that if current chronic disturbances remain, they will result in increasingly poorer phylogenetically forests. This loss of evolutionary history will potentially limit the capacity of this ecosystem to respond to human disturbances (i.e., lower ecological resilience) and particularly their ability to adapt to rapid climatic changes in the region.

Batch Isolation of Microsatellites for Tropical Plant Species Pyrosequencing

USDA-ARS?s Scientific Manuscript database

Microsatellites were developed for ten tropical species using a method recently developed in our laboratory that involves a combination of two adapters at the SSR-enrichment stage and allows for cost saving and simultaneous loading of samples. The species for which microsatellites were isolated are...

Plant phylogeny as a window on the evolution of hyperdiversity in the tropical rainforest biome.

PubMed

Eiserhardt, Wolf L; Couvreur, Thomas L P; Baker, William J

2017-06-01

I. II. III. IV. V. VI. VII. VIII. IX. References SUMMARY: Tropical rainforest (TRF) is the most species-rich terrestrial biome on Earth, harbouring just under half of the world's plant species in c. 7% of the land surface. Phylogenetic trees provide important insights into mechanisms underpinning TRF hyperdiversity that are complementary to those obtained from the fossil record. Phylogenetic studies of TRF plant diversity have mainly focused on whether this biome is an evolutionary 'cradle' or 'museum', emphasizing speciation and extinction rates. However, other explanations, such as biome age, immigration and ecological limits, must also be considered. We present a conceptual framework for addressing the drivers of TRF diversity, and review plant studies that have tested them with phylogenetic data. Although surprisingly few in number, these studies point to old age of TRF, low extinction and high speciation rates as credible drivers of TRF hyperdiversity. There is less evidence for immigration and ecological limits, but these cannot be dismissed owing to the limited number of studies. Rapid methodological developments in DNA sequencing, macroevolutionary analysis and the integration of phylogenetics with other disciplines may improve our grasp of TRF hyperdiversity in the future. However, such advances are critically dependent on fundamental systematic research, yielding numerous, additional, well-sampled phylogenies of TRF lineages. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Optimal use of land surface temperature data to detect changes in tropical forest cover

NASA Astrophysics Data System (ADS)

Van Leeuwen, T. T.; Frank, A. J.; Jin, Y.; Smyth, P.; Goulden, M.; van der Werf, G.; Randerson, J. T.

2011-12-01

Rapid and accurate assessment of global forest cover change is needed to focus conservation efforts and to better understand how deforestation is contributing to the build up of atmospheric CO2. Here we examined different ways to use remotely sensed land surface temperature (LST) to detect changes in tropical forest cover. In our analysis we used monthly 0.05×0.05 degree Terra MODerate Resolution Imaging Spectroradiometer (MODIS) observations of LST and PRODES (Program for the Estimation of Deforestation in the Brazilian Amazon) estimates of forest cover change. We also compared MODIS LST observations with an independent estimate of forest cover loss derived from MODIS and Landsat observations. Our study domain of approximately 10×10 degree included most of the Brazilian state of Mato Grosso. For optimal use of LST data to detect changes in tropical forest cover in our study area, we found that using data sampled during the end of the dry season (~1-2 months after minimum monthly precipitation) had the greatest predictive skill. During this part of the year, precipitation was low, surface humidity was at a minimum, and the difference between day and night LST was the largest. We used this information to develop a simple temporal sampling algorithm appropriate for use in pan-tropical deforestation classifiers. Combined with the normalized difference vegetation index (NDVI), a logistic regression model using day-night LST did moderately well at predicting forest cover change. Annual changes in day-night LST difference decreased during 2006-2009 relative to 2001-2005 in many regions within the Amazon, providing independent confirmation of lower deforestation levels during the latter part of this decade as reported by PRODES. The use of day-night LST differences may be particularly valuable for use with satellites that do not have spectral bands that allow for the estimation of NDVI or other vegetation indices.

The Origins of Tropical Rainforest Hyperdiversity.

PubMed

Pennington, R Toby; Hughes, Mark; Moonlight, Peter W

2015-11-01

Traditional models for tropical species richness contrast rainforests as "museums" of old species or "cradles" of recent speciation. High plant species diversity in rainforests may be more likely to reflect high episodic evolutionary turnover of species--a scenario implicating high rates of both speciation and extinction through geological time.

Diversity and host range of foliar fungal endophytes: are tropical leaves biodiversity hotspots?

PubMed

Arnold, A Elizabeth; Lutzoni, F

2007-03-01

Fungal endophytes are found in asymptomatic photosynthetic tissues of all major lineages of land plants. The ubiquity of these cryptic symbionts is clear, but the scale of their diversity, host range, and geographic distributions are unknown. To explore the putative hyperdiversity of tropical leaf endophytes, we compared endophyte communities along a broad latitudinal gradient from the Canadian arctic to the lowland tropical forest of central Panama. Here, we use molecular sequence data from 1403 endophyte strains to show that endophytes increase in incidence, diversity, and host breadth from arctic to tropical sites. Endophyte communities from higher latitudes are characterized by relatively few species from many different classes of Ascomycota, whereas tropical endophyte assemblages are dominated by a small number of classes with a very large number of endophytic species. The most easily cultivated endophytes from tropical plants have wide host ranges, but communities are dominated by a large number of rare species whose host range is unclear. Even when only the most easily cultured species are considered, leaves of tropical trees represent hotspots of fungal species diversity, containing numerous species not yet recovered from other biomes. The challenge remains to recover and identify those elusive and rarely cultured taxa with narrower host ranges, and to elucidate the ecological roles of these little-known symbionts in tropical forests.

Taxonomic and phylogenetic diversity of vascular plants at Ma'anling volcano urban park in tropical Haikou, China: Reponses to soil properties.

PubMed

Cheng, Xia-Lan; Yuan, Lang-Xing; Nizamani, Mir Mohammad; Zhu, Zhi-Xin; Friedman, Cynthia Ross; Wang, Hua-Feng

2018-01-01

Anthropogenic processes and socio-economic factors play important roles in shaping plant diversity in urban parks. To investigate how plant diversity of Ma' anling urban volcano park in Hainan Province, China respond to these factors, we carried out a field investigation on the taxonomic and phylogenetic diversity of vascular plants and soil properties in this area. We found 284 species of vascular plants belonging to 88 families and 241 genera, which included 194 native species, 23 invasive species, 31 naturalized species, 40 cultivars, and 4 rare / endangered plant species. Tree composition and richness significantly varied between different vegetation formations (plantation, secondary forest, and abandoned land). Plant species richness and community composition were significantly affected by elevation (El), soil water content (WC), total soil nitrogen (TN) and soil organic matter (SOM). There were significant diversity differences between plantations and abandoned lands, but not between the plantations and secondary forests. The flora in the study site was tropical in nature, characterized by pantropic distributions. Compared to adjacent areas, floristic composition in the study site was most similar to that of Guangdong, followed by that of Vietnam. Our study revealed the diversity patterns of volcanic plants and provided the basis for future planning of plant conservation, such as preserving plant species, maintaining plant habitats, and coordinating plant management in this region.

Trichuris trichiura in a post-Colonial Brazilian mummy.

PubMed

Bianucci, Rafaella; Torres, Eduardo J Lopes; Santiago, Juliana M F Dutra; Ferreira, Luis F; Nerlich, Andreas G; Souza, Sheila Maria Mendonça de; Giuffra, Valentina; Chieffi, Pedro Paulo; Bastos, Otilio Maria; Travassos, Renata; Souza, Wanderley de; Araújo, Adauto

2015-02-01

Trichuris trichiura is a soil-transmitted helminth which is prevalent in warm, moist, tropical and subtropical regions of the world with poor sanitation. Heavy whipworm can result either in Trichuris dysenteric syndrome - especially in children - or in a chronic colitis. In heavy infections, worms can spread proximally and may cause ileitis. Here we provide first microscopic evidence for a T. trichiura adult worm embedded in the rectum of a post-Colonial Brazilian adult mummy. During Colonial and post-Colonial times, many European chroniclers described a parasitic disease named Maculo whose symptomatology coincides with heavy helminthiasis. Based on our findings and on comparison of ancient textual evidence with modern description of heavy whipworm, we feel confident in considering that the two syndromes are expressions of the same pathological condition.

Trichuris trichiura in a post-Colonial Brazilian mummy

PubMed Central

Bianucci, Rafaella; Torres, Eduardo J Lopes; Santiago, Juliana MF Dutra; Ferreira, Luis F; Nerlich, Andreas G; de Souza, Sheila Maria Mendonça; Giuffra, Valentina; Chieffi, Pedro Paulo; Bastos, Otilio Machado; Travassos, Renata; de Souza, Wanderley; Araújo, Adauto

2015-01-01

Trichuris trichiura is a soil-transmitted helminth which is prevalent in warm, moist, tropical and subtropical regions of the world with poor sanitation. Heavy whipworm can result either in Trichuris dysenteric syndrome - especially in children - or in a chronic colitis. In heavy infections, worms can spread proximally and may cause ileitis. Here we provide first microscopic evidence for a T. trichiura adult worm embedded in the rectum of a post-Colonial Brazilian adult mummy. During Colonial and post-Colonial times, many European chroniclers described a parasitic disease named Maculo whose symptomatology coincides with heavy helminthiasis. Based on our findings and on comparison of ancient textual evidence with modern description of heavy whipworm, we feel confident in considering that the two syndromes are expressions of the same pathological condition. PMID:25742276

Edge fires drive the shape and stability of tropical forests.

PubMed

Hébert-Dufresne, Laurent; Pellegrini, Adam F A; Bhat, Uttam; Redner, Sidney; Pacala, Stephen W; Berdahl, Andrew M

2018-06-01

In tropical regions, fires propagate readily in grasslands but typically consume only edges of forest patches. Thus, forest patches grow due to tree propagation and shrink by fires in surrounding grasslands. The interplay between these competing edge effects is unknown, but critical in determining the shape and stability of individual forest patches, as well the landscape-level spatial distribution and stability of forests. We analyze high-resolution remote-sensing data from protected Brazilian Cerrado areas and find that forest shapes obey a robust perimeter-area scaling relation across climatic zones. We explain this scaling by introducing a heterogeneous fire propagation model of tropical forest-grassland ecotones. Deviations from this perimeter-area relation determine the stability of individual forest patches. At a larger scale, our model predicts that the relative rates of tree growth due to propagative expansion and long-distance seed dispersal determine whether collapse of regional-scale tree cover is continuous or discontinuous as fire frequency changes. © 2018 The Authors. Ecology Letters published by CNRS and John Wiley & Sons Ltd.

Estimating forest biomass and identifying low-intensity logging areas using airborne scanning lidar in Antimary State Forest, Acre State, Western Brazilian Amazon

Treesearch

Marcus V.N. d' Oliveira; Stephen E. Reutebuch; Robert J. McGaughey; Hans-Erik. Andersen

2012-01-01

The objectives of this study were to estimate above ground forest biomass and identify areas disturbed by selective logging in a 1000 ha Brazilian tropical forest in the Antimary State Forest using airborne lidar data. The study area consisted of three management units, two of which were unlogged, while the third unit was selectively logged at a low intensity. A...

Vasorelaxation induced by common edible tropical plant extracts in isolated rat aorta and mesenteric vascular bed.

PubMed

Runnie, I; Salleh, M N; Mohamed, S; Head, R J; Abeywardena, M Y

2004-06-01

In this study, the vasodilatory actions of nine edible tropical plant extracts were investigated. Ipomoea batatas (sweet potato leaf), Piper betle (betel leaf), Anacardium occidentale (cashew leaf), Gynandropsis gynandra (maman leaf), Carica papaya (papaya leaf), and Mentha arvensis (mint leaf) extracts exhibited more than 50% relaxing effect on aortic ring preparations, while Piper betle and Cymbopogon citratus (lemongrass stalk) showed comparable vasorelaxation on isolated perfused mesenteric artery preparation. The vascular effect on the aortic ring preparations were mainly endothelium-dependent, and mediated by nitric oxide (NO) as supported by the inhibition of action in the presence of N(omega)-nitro-L-arginine (NOLA), an nitric oxide synthase (NOS) inhibitor, or by the removal of endothelium. In contrast, vasodilatory actions in resistance vessels (perfused mesenteric vascular beds) appear to involve several biochemical mediators, including NO, prostanoids, and endothelium-dependent hyperpolarizing factors (EDHFs). Total phenolic contents and antioxidant capacities varied among different extracts and found to be independent of vascular relaxation effects. This study demonstrates that many edible plants common in Asian diets to possess potential health benefits, affording protection at the vascular endothelium level.

Brazilian medicinal plants to treat upper respiratory tract and bronchial illness: systematic review and meta-analyses-study protocol.

PubMed

Lopes, Luciane C; Silva, Maria Carolina O; Motta, Cristiane Bergamashi; Macho Quirós, Antonio; Biavatti, Maique Weber; de Oliveira, Jardel Corrêa; Guyatt, Gordon

2014-07-23

Respiratory illness, often associated with cough and sputum, is frequent. In Brazil, herbal medicines are often recommended as a first-line treatment for respiratory illness. There exists uncertainty regarding the effectiveness of these treatments. No systematic review has evaluated Brazilian medicinal plants (BMP) to treat upper respiratory tract and bronchial illness (URTI). We will conduct a systematic review and, if appropriate, a series of meta-analyses evaluating the safety and effectiveness of BMP for URTI. Eligible randomised controlled trials and observational studies will enrol adult or paediatric patients presenting with URTI treated by BMP approved by the Brazilian Health Surveillance Agency compared with placebo, no treatment or an alternative therapy. Our search will include the Cochrane Central Register of Controlled Trials (CENTRAL), which contains the Cochrane Acute Respiratory Illness Group's Specialized Register; MEDLINE; EMBASE; CINAHL (Cumulative Index to Nursing and Allied Health Literature); Web of Science; AMED; LILACS; CAB abstracts; clinical trial.gov; the WHO Trial Register and the Brazilian thesis database (CAPES) without any language restrictions. Outcomes of interest are time to resolution of clinical symptoms and/or signs (cough, sputum production or activity limitations), severity of symptoms prior to resolution and major/minor adverse events. Teams of reviewers will, independently and in duplicate, screen titles and abstracts and the complete full text to determine eligibility. For eligible studies, reviewers will perform data abstraction and assess risk of bias of eligible trials. When appropriate, we will conduct meta-analyses. We will also assess the quality of body of evidence (confidence in estimates of effect) for each of the outcomes using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. The systematic review will be published in a peer-reviewed journal. Brief reports of review findings

Brazilian medicinal plants to treat upper respiratory tract and bronchial illness: systematic review and meta-analyses—study protocol

PubMed Central

Lopes, Luciane C; Silva, Maria Carolina O; Motta, Cristiane Bergamashi; Macho Quirós, Antonio; Biavatti, Maique Weber; de Oliveira, Jardel Corrêa; Guyatt, Gordon

2014-01-01

Introduction Respiratory illness, often associated with cough and sputum, is frequent. In Brazil, herbal medicines are often recommended as a first-line treatment for respiratory illness. There exists uncertainty regarding the effectiveness of these treatments. No systematic review has evaluated Brazilian medicinal plants (BMP) to treat upper respiratory tract and bronchial illness (URTI). Methods and analysis We will conduct a systematic review and, if appropriate, a series of meta-analyses evaluating the safety and effectiveness of BMP for URTI. Eligible randomised controlled trials and observational studies will enrol adult or paediatric patients presenting with URTI treated by BMP approved by the Brazilian Health Surveillance Agency compared with placebo, no treatment or an alternative therapy. Our search will include the Cochrane Central Register of Controlled Trials (CENTRAL), which contains the Cochrane Acute Respiratory Illness Group's Specialized Register; MEDLINE; EMBASE; CINAHL (Cumulative Index to Nursing and Allied Health Literature); Web of Science; AMED; LILACS; CAB abstracts; clinical trial.gov; the WHO Trial Register and the Brazilian thesis database (CAPES) without any language restrictions. Outcomes of interest are time to resolution of clinical symptoms and/or signs (cough, sputum production or activity limitations), severity of symptoms prior to resolution and major/minor adverse events. Teams of reviewers will, independently and in duplicate, screen titles and abstracts and the complete full text to determine eligibility. For eligible studies, reviewers will perform data abstraction and assess risk of bias of eligible trials. When appropriate, we will conduct meta-analyses. We will also assess the quality of body of evidence (confidence in estimates of effect) for each of the outcomes using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Ethics and dissemination The systematic review will be published in

Are community-based forest enterprises in the tropics financially viable? Case studies from the Brazilian Amazon

Treesearch

Shoana Humphries; Thomas P. Holmes; Karen Kainer; Carlos Gabriel Goncalves Koury; Edson Cruz; Rosana de Miranda Rocha

2012-01-01

Community-based forest management is an integral component of sustainable forest management and conservation in the Brazilian Amazon, where it has been heavily subsidized for the last ten years. Yet knowledge of the financial viability and impact of community-based forest enterprises (CFEs) is lacking. This study evaluates the profitability of three CFEs in the...

Publication in a Brazilian journal by Brazilian scientists whose papers have international impact.

PubMed

Meneghini, R

2010-09-01

Nine Brazilian scientists with an outstanding profile of international publications were invited to publish an original article in the same issue of a Brazilian Journal (Anais da Academia Brasileira de Ciências). The objective was to measure the impact of the papers on the number of citations to the articles, the assumption being that these authors would carry their international prestige to the Brazilian periodical. In a 2-year period there was a larger number of citations of these articles compared to others published in the same journal. Nevertheless, the number of citations in Brazilian journals did not equal the number of citations obtained by the other papers by the same authors in their international publications within the same 2-year period. The reasons for this difference in the number of citations could be either that less significant invited articles were submitted or that it was due to the intrinsic lack of visibility of the Brazilian journals, but this could not be fully determined with the present data. Also relevant was a comparison between the citations of Brazilian journals and the publication in Brazilian journals by these selected authors. A clear imbalance due to a remarkable under-citation of Brazilian authors by authors publishing in Brazilian journals raises the possibility that psychological factors may affect the decision of citing Brazilian journals.

Species differences in nitrogen cycling in a humid sub-tropical forest inferred from 15N natural abundance

NASA Astrophysics Data System (ADS)

Abdisa Gurmesa, Geshere; Lu, Xiankai; Gundersen, Per; Mao, Qinggong; Zhou, Kaijun; Mo, Jiangming

2017-04-01

Studies of natural abundance of stable nitrogen isotope (δ15N) of ecosystems can provide integrated information about N status and N cycling rates within the ecosystems. Plant species with different N cycling traits can affect ecosystem δ15N, but such differences are poorly explored in tropical forests. This study evaluates the extent of variation in plant δ15N among co-occurring sub-tropical tropical tree species in old-growth mixed broadleaved forest in southern China. We compared leaf δ15N values among five co-occurring tree species under ambient deposition (control plots), and variation in plant δ15N response to a decade of N addition (N-plots) and to a one-year enriched 15N addition to both treatments in the study forest. We found significant differences in leaf δ15N values among tree species (up to 3‰) both in control and N-plots. Responses of leaf δ15N to N and 15N addition also differ among the tree species. These differences are explained by differences in N acquisition strategies (dependence on soil N and/or deposition N among the plant species) that is partly related to differences in mycorrhizal association among the studied plants. Our results indicate that plant species in N-rich tropical forests could have distinct N cycling traits as observed in many predominantly N-limited temperate and boreal forests. The finding, therefore, highlights the importance of considering tree species variation in studying N cycling in N-rich tropical forests.

The underestimated biodiversity of tropical grassy biomes.

PubMed

Murphy, Brett P; Andersen, Alan N; Parr, Catherine L

2016-09-19

For decades, there has been enormous scientific interest in tropical savannahs and grasslands, fuelled by the recognition that they are a dynamic and potentially unstable biome, requiring periodic disturbance for their maintenance. However, that scientific interest has not translated into widespread appreciation of, and concern about threats to, their biodiversity. In terms of biodiversity, grassy biomes are considered poor cousins of the other dominant biome of the tropics-forests. Simple notions of grassy biomes being species-poor cannot be supported; for some key taxa, such as vascular plants, this may be valid, but for others it is not. Here, we use an analysis of existing data to demonstrate that high-rainfall tropical grassy biomes (TGBs) have vertebrate species richness comparable with that of forests, despite having lower plant diversity. The Neotropics stand out in terms of both overall vertebrate species richness and number of range-restricted vertebrate species in TGBs. Given high rates of land-cover conversion in Neotropical grassy biomes, they should be a high priority for conservation and greater inclusion in protected areas. Fire needs to be actively maintained in these systems, and in many cases re-introduced after decades of inappropriate fire exclusion. The relative intactness of TGBs in Africa and Australia make them the least vulnerable to biodiversity loss in the immediate future. We argue that, like forests, TGBs should be recognized as a critical-but increasingly threatened-store of global biodiversity.This article is part of the themed issue 'Tropical grassy biomes: linking ecology, human use and conservation'. © 2016 The Author(s).

Vegetation and floristics of a lowland tropical rainforest in northeast Australia

PubMed Central

Apgaua, Deborah M. G.; Campbell, Mason J; Cox, Casey J; Crayn, Darren M; Ishida, Françoise Y; Laidlaw, Melinda J; Liddell, Michael J; Seager, Michael; Laurance, Susan G. W.

2016-01-01

Abstract Background Full floristic data, tree demography, and biomass estimates incorporating non-tree lifeforms are seldom collected and reported for forest plots in the tropics. Established research stations serve as important repositories of such biodiversity and ecological data. With a canopy crane setup within a tropical lowland rainforest estate, the 42-ha Daintree Rainforest Observatory (DRO) in Cape Tribulation, northern Australia is a research facility of international significance. We obtained an estimate of the vascular plant species richness for the site, by surveying all vascular plant species from various mature-phase, remnant and open vegetation patches within the site. We also integrate and report the demography and basal areas of trees ≥ 10 cm diameter at breast height (dbh) in a new 1-ha core plot, an extension to the pre-existing forest 1-ha plot under the canopy crane. In addition, we report for the canopy crane plot new demography and basal areas for smaller-size shrubs and treelets subsampled from nine 20 m2 quadrats, and liana basal area and abundance from the whole plot. The DRO site has an estimated total vascular plant species richness of 441 species, of which 172 species (39%) are endemic to Australia, and 4 species are endemics to the Daintree region. The 2 x 1-ha plots contains a total of 262 vascular plant species of which 116 (1531 individuals) are tree species ≥ 10 cm dbh. We estimate a stem basal area of 34.9 m2 ha-1, of which small stems (tree saplings and shrubs <10cm dbh) and lianas collectively contribute c.4.2%. Comparing the stem density-diversity patterns of the DRO forest with other tropical rainforests globally, our meta-analysis shows that DRO forests has a comparatively high stem density and moderate species diversity, due to the influence of cyclones. These data will provide an important foundation for ecological and conservation studies in lowland tropical forest. New information We present a floristic checklist, a

Tritium behavior pattern in some soil-plant systems in a tropical environment

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

Soma, S.D.; Iyengar, T.S.; Sadarangani, S.H.

1975-01-01

A study of the distribution pattern of tritium in the soil/plant environment gives a valuable ecological information on the natural water balance. The results of such a study for the conditions obtaining in India are given in this paper. Field studies are carried out by injection of tritium into some soil/ plant systems and following the transfer pathways. The method of extraction for tissue-free-water-tritium (TFWT) is based on the vacuum freeze-drying technique while the tissue-bound-tritium (TBT) is estimated by a modified version of the Shoniger method. The determination of residence time of tritium in aqueous and organic phase in amore » number of tropical trees has been carried out both for stem- injection as well as intake from the soil. From the results of this study the tree biomass and transpiration rates have been determined. The tritium profile over time, for an acute exposure in certain trees such as Morinda Tinetoria, Achras Sapota etc. shows significantly different patterns compared to the normal pattern shown by Mangifera Indica, Terminalia Catappa, Ficus Glomerata etc. The period of investigation in each case varied from 400 to 1000 h. In most of the cases, the TBT fractions were very low compared to TFWT fractions in the initial stages. The tritium behaviour in the tree reflects significant characteristics of the tritium behaviour in the soil system. The authors have found that the leaf sampling can be used as an indicator of total environmental tritium behaviour. (auth)« less

The transparency, reliability and utility of tropical rainforest land-use and land-cover change models.

PubMed

Rosa, Isabel M D; Ahmed, Sadia E; Ewers, Robert M

2014-06-01

Land-use and land-cover (LULC) change is one of the largest drivers of biodiversity loss and carbon emissions globally. We use the tropical rainforests of the Amazon, the Congo basin and South-East Asia as a case study to investigate spatial predictive models of LULC change. Current predictions differ in their modelling approaches, are highly variable and often poorly validated. We carried out a quantitative review of 48 modelling methodologies, considering model spatio-temporal scales, inputs, calibration and validation methods. In addition, we requested model outputs from each of the models reviewed and carried out a quantitative assessment of model performance for tropical LULC predictions in the Brazilian Amazon. We highlight existing shortfalls in the discipline and uncover three key points that need addressing to improve the transparency, reliability and utility of tropical LULC change models: (1) a lack of openness with regard to describing and making available the model inputs and model code; (2) the difficulties of conducting appropriate model validations; and (3) the difficulty that users of tropical LULC models face in obtaining the model predictions to help inform their own analyses and policy decisions. We further draw comparisons between tropical LULC change models in the tropics and the modelling approaches and paradigms in other disciplines, and suggest that recent changes in the climate change and species distribution modelling communities may provide a pathway that tropical LULC change modellers may emulate to further improve the discipline. Climate change models have exerted considerable influence over public perceptions of climate change and now impact policy decisions at all political levels. We suggest that tropical LULC change models have an equally high potential to influence public opinion and impact the development of land-use policies based on plausible future scenarios, but, to do that reliably may require further improvements in the

Ecological study of the effects of power plants on benthic macroplant microcosms in subtropical and tropical estuaries. Annual progress report, 1977-1978

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

Thorhaug, A.; Schroeder, P.

1978-01-01

The major efforts have been to examine the effects of energy-related problems on nearshore environments in the subtropics and tropics of the Atlantic and Gulf of Mexico regions of the United States and the Caribbean. Two fossil fuel and two nuclear plants were examined as the their effects on a nearshore seagrass community at Turkey Point in south Biscayne Bay, Dade County, Florida. The effects of heat toxicity, trace (heavy) metals and high salinities, the community processes and dynamics of nearshore subtropical and tropical seagrass ecosystems, and primary productivity and physiology of the dominant food chain organisms in these ecosystemsmore » have been studied in detail in both field and laboratory studies. A model for future prediction of pollutants emanating from energy-related resources and their effect on seagrass ecosystems has been included.« less

Evaluation of Antileishmanial Activity of Selected Brazilian Plants and Identification of the Active Principles

PubMed Central

Filho, Valdir Cechinel; Meyre-Silva, Christiane; Niero, Rivaldo; Bolda Mariano, Luisa Nathália; Gomes do Nascimento, Fabiana; Vicente Farias, Ingrid; Gazoni, Vanessa Fátima; dos Santos Silva, Bruna; Giménez, Alberto; Gutierrez-Yapu, David; Salamanca, Efrain; Malheiros, Angela

2013-01-01

This study evaluated extracts, fractions, and isolated compounds from some selected Brazilian medicinal plants against strains of promastigotes of Leishmania amazonensis and L. brasiliensis in vitro. The cell viability was determined, comparing the results with reference standards. The dichloromethane fractions of the roots, stems, and leaves of Allamanda schottii showed IC50 values between 14.0 and 2.0 μg/mL. Plumericin was the main active compound, with IC50 of 0.3 and 0.04 μg/mL against the two species of Leishmania analyzed. The hexane extract of Eugenia umbelliflora fruits showed IC50 of 14.3 and 5.7 μg/mL against L. amazonensis and L. brasiliensis, respectively. The methanolic extracts of the seeds of Garcinia achachairu and guttiferone A presented IC50 values of 35.9 and 10.4 μg/mL, against L. amazonensis, respectively. The ethanolic extracts of the stem barks of Rapanea ferruginea and the isolated compound, myrsinoic acid B, presented activity against L. brasiliensis with IC50 of 24.1 and 6.1 μg/mL. Chloroform fraction of Solanum sisymbriifolium exhibited IC50 of 33.8 and 20.5 μg/mL, and cilistol A was the main active principle, with IC50 of 6.6 and 3.1 μg/mL against L. amazonensis and L. brasiliensis, respectively. It is concluded that the analyzed plants are promising as new and effective antiparasitic agents. PMID:23840252

Interactions Between the Thermohaline Circulation and Tropical Atlantic SST in a Coupled General Circulation Model

NASA Technical Reports Server (NTRS)

Miller, Ron; Jiang, Xing-Jian; Travis, Larry (Technical Monitor)

2001-01-01

Tropical Atlantic SST shows a (statistically well-defined) decadal time scale in a 104-year simulation of unforced variability by a coupled general circulation model (CGCM). The SST anomalies superficially resemble observed Tropical Atlantic variability (TAV), and are associated with changes in the atmospheric circulation. Brazilian rainfall is modulated with a decadal time scale, along with the strength of the Atlantic trade winds, which are associated with variations in evaporation and the net surface heat flux. However, in contrast to observed tropical Atlantic variability, the trade winds damp the associated anomalies in ocean temperature, indicating a negative feedback. Tropical SST anomalies in the CGCM, though opposed by the surface heat flux, are advected in from the Southern Hemisphere mid-latitudes. These variations modulate the strength of the thermohaline circulation (THC): warm, salty anomalies at the equator sink drawing cold, fresh mid-latitude water. Upon reaching the equator, the latter inhibit vertical overturning and advection from higher latitudes, which allows warm, salty anomalies to reform, returning the cycle to its original state. Thus, the cycle results from advection of density anomalies and the effect of these anomalies upon the rate of vertical overturning and surface advection. This decadal modulation of Tropical Atlantic SST and the thermohaline circulation is correlated with ocean heat transport to the Northern Hemisphere high latitudes and Norwegian Sea SST. Because of the central role of equatorial convection, we question whether this mechanism is present in the current climate, although we speculate that it may have operated in palaeo times, depending upon the stability of the tropical water column.

Training and Operations Integrated Calendar Scheduler - TROPICS

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

J.E. Oppenlander; A.J. Levy; V.A. Arbige

2003-01-27

TROPICS is a rule-based scheduling system that optimizes the training experience for students in a power (note this change should be everywhere, i.e. Not reactor) plant environment. The problem is complicated by the condition that plant resources and users' time must be simultaneously scheduled to make best use of both. The training facility is highly constrained in how it is used, and, as in many similar environments, subject to dynamic change with little or no advance notice. The flexibility required extends to changes resulting from students' actions such as absences. Even though the problem is highly constrained by plant usagemore » and student objectives, the large number of possible schedules is a concern. TROPICS employs a control strategy for rule firing to prune the possibility tree and avoid combinatorial explosion. The application has been in use since 1996, first as a prototype for testing and then in production. Training Coordinators have a philosophical aspect to teaching students that has made the rule-based approach much more verifiable and satisfying to the domain experts than other forms of capturing expertise.« less

Ecology of Nitrogen Fixing, Nitrifying, and Denitrifying Microorganisms in Tropical Forest Soils

PubMed Central

Pajares, Silvia; Bohannan, Brendan J. M.

2016-01-01

Soil microorganisms play important roles in nitrogen cycling within forest ecosystems. Current research has revealed that a wider variety of microorganisms, with unexpected diversity in their functions and phylogenies, are involved in the nitrogen cycle than previously thought, including nitrogen-fixing bacteria, ammonia-oxidizing bacteria and archaea, heterotrophic nitrifying microorganisms, and anammox bacteria, as well as denitrifying bacteria, archaea, and fungi. However, the vast majority of this research has been focused in temperate regions, and relatively little is known regarding the ecology of nitrogen-cycling microorganisms within tropical and subtropical ecosystems. Tropical forests are characterized by relatively high precipitation, low annual temperature fluctuation, high heterogeneity in plant diversity, large amounts of plant litter, and unique soil chemistry. For these reasons, regulation of the nitrogen cycle in tropical forests may be very different from that of temperate ecosystems. This is of great importance because of growing concerns regarding the effect of land use change and chronic-elevated nitrogen deposition on nitrogen-cycling processes in tropical forests. In the context of global change, it is crucial to understand how environmental factors and land use changes in tropical ecosystems influence the composition, abundance and activity of key players in the nitrogen cycle. In this review, we synthesize the limited currently available information regarding the microbial communities involved in nitrogen fixation, nitrification and denitrification, to provide deeper insight into the mechanisms regulating nitrogen cycling in tropical forest ecosystems. We also highlight the large gaps in our understanding of microbially mediated nitrogen processes in tropical forest soils and identify important areas for future research. PMID:27468277

The Use of Proteomic Tools to Address Challenges Faced in Clonal Propagation of Tropical Crops through Somatic Embryogenesis.

PubMed

Chin, Chiew Foan; Tan, Hooi Sin

2018-05-04

In many tropical countries with agriculture as the mainstay of the economy, tropical crops are commonly cultivated at the plantation scale. The successful establishment of crop plantations depends on the availability of a large quantity of elite seedling plants. Many plantation companies establish plant tissue culture laboratories to supply planting materials for their plantations and one of the most common applications of plant tissue culture is the mass propagation of true-to-type elite seedlings. However, problems encountered in tissue culture technology prevent its applications being widely adopted. Proteomics can be a powerful tool for use in the analysis of cultures, and to understand the biological processes that takes place at the cellular and molecular levels in order to address these problems. This mini review presents the tissue culture technologies commonly used in the propagation of tropical crops. It provides an outline of some the genes and proteins isolated that are associated with somatic embryogenesis and the use of proteomic technology in analysing tissue culture samples and processes in tropical crops.

THE TROPICAL AND SUBTROPICAL GERMPLASM COLLECTIONS AT THE NATIONAL GERMPLASM REPOSITORY IN MIAMI, FL

USDA-ARS?s Scientific Manuscript database

The Subtropical and Tropical USDA, ARS, National Germplasm Repositories (NGR) in Miami, FL; Mayaguez, PR; and Hilo, HI are responsible for the collections of subtropical and tropical fruits, nuts, grasses, and ornamentals for the USDA, ARS, National Plant Germplasm System (NPGS). The NPGS is respons...

Variation in life-history traits and their plasticities to elevational transplantation among seed families suggests potential for adaptative evolution of 15 tropical plant species to climate change.

PubMed

Ensslin, Andreas; Fischer, Markus

2015-08-01

• Because not all plant species will be able to move in response to global warming, adaptive evolution matters largely for plant persistence. As prerequisites for adaptive evolution, genetic variation in and selection on phenotypic traits are needed, but these aspects have not been studied in tropical species. We studied how plants respond to transplantation to different elevations on Mt. Kilimanjaro, Tanzania, and whether there is quantitative genetic (among-seed family) variation in and selection on life-history traits and their phenotypic plasticity to the different environments.• We reciprocally transplanted seed families of 15 common tropical, herbaceous species of the montane and savanna vegetation zone at Mt. Kilimanjaro to a watered experimental garden in the montane (1450 m) and in the savanna (880 m) zone at the mountain's slope and measured performance, reproductive, and phenological traits.• Plants generally performed worse in the savanna garden, indicating that the savanna climate was more stressful and thus that plants may suffer from future climate warming. We found significant quantitative genetic variation in all measured performance and reproductive traits in both gardens and for several measures of phenotypic plasticity in response to elevational transplantation. Moreover, we found positive selection on traits at low and intermediate trait values levelling to neutral or negative selection at high values.• We conclude that common plants at Mt. Kilimanjaro express quantitative genetic variation in fitness-relevant traits and in their plasticities, suggesting potential to adapt evolutionarily to future climate warming and increased temperature variability. © 2015 Botanical Society of America, Inc.

Plant phenological water cycle and implications for using δ2H-alkanes as paleo proxy in a semi-arid tropical climate

NASA Astrophysics Data System (ADS)

De Wispelaere, Lien; Bodé, Samuel; Hervé-Fernández, Pedro; Hemp, Andreas; Verschuren, Dirk; Boeckx, Pascal

2017-04-01

Lake Challa is a steep-sided crater lake situated in equatorial East Africa, a tropical semi-arid area with bimodal rainfall pattern. The δ2H and δ18O of precipitation, lake water, groundwater, plant xylem water and plant leaf water were measured across different plant species, seasons and plant habitats in the vicinity of Lake Challa, as well as the hydrogen-isotopic composition of leaf wax n-alkanes (δ2Hwax). Long chain n-alkanes of terrestrial plant leaf waxes provide information on plant-water relations and have been widely used as proxy in paleoclimate and paleovegetation reconstructions. In our study, we found that plants rely mostly on water from the 'short rains' falling from October till December (northeast monsoon), as these recharge the soil pores after the long dry season. This plant-available, static, water pool is only slightly replenished by the 'long rains' falling from February to May (southeast monsoon), in agreement with the 'two water world' hypothesis according to which plants rely on a static water pool separated from a more mobile water pool that recharges the groundwater. Spatial variability in water resource use exists in the study region with plants at the lakeshore relying on water of different isotopic composition, i.e isotopically evaporated lake water at the lakeshore vs. non- or slightly evaporated precipitation in the savannah and on the crater rim. This spatial resource partitioning is recorded by elevated δ2H values in the leaf wax lipids of plants at the lakeshore. The distribution of n-alkanes in the fresh leaves shows a unimodal distribution pattern reaching a maximum at n-C29 and n-C31 for both shrubs and trees, while C4 grasses are dominated by n-C31. However, the relative abundance of n-C31 was higher at the lakeshore compared to the savannah and crater rim (when grasses were not included). According to our results, plant species and their associated leaf phenology are the primary factors influencing the enrichment in

Inorganic profile of some Brazilian medicinal plants obtained from ethanolic extract and ''in natura'' samples

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

Ferreira, M.O.M.; de Sousa, P.T.; Salvador, V.L.R.

The Anadenathera macrocarpa, Schinus molle, Hymenaea courbaril, Cariniana legalis, Solidago microglossa and Stryphnodendron barbatiman, were collected ''in natura'' samples (leaves, flowers, barks and seeds) from different commercial suppliers. The pharmaco-active compounds in ethanolic extracts had been made by the Mato Grosso Federal University (UFMT). The energy-dispersive x-ray fluorescence (ED-XRF) spectrometry was used for the elemental analysis in different parts of the plants and respective ethanolic extracts. The Ca, Cl, Cu, Fe, K, Mg, Mn, Na, Ni, P, Rb, S, Sr and Zn concentrations were determined by the fundamental parameters method. Some specimens showed a similar inorganic profile for ''in natura''more » and ethanolic extract samples and some ones showed a distinct inorganic profile. For example, the Anadenathera macrocarpa showed a similar concentration in Mg, P, Cu, Zn and Rb elements in ''in natura'' and ethanolic extract samples; however very different concentration in Na, S, Cl, K , Ca, Mn, Fe and Sr was observed in distinctive samples. The Solidago microglossa showed the K, Ca, Cl, S, Mg, P and Fe elements as major constituents in both samples, suggesting that the extraction process did not affect in a considerable way the ''in natura'' inorganic composition. The elemental composition of the different parts of the plants (leaves, flowers, barks and seeds) has been also determined. For example, the Schinus molle specimen showed P, K, Cl and Ca elements as major constituents in the seeds, Mg, K and Sr in the barks and Mg, S, Cl and Mn in the leaves, demonstrating a differentiated elementary distribution. These inorganic profiles will contribute to evaluate the quality control of the Brazilian herbaceous trade and also will assist to identify which parts of the medicinal plants has greater therapeutic effect.« less

Paleohydrology Reconstruction of the Tropical South America for the Past 1.6 Million Years.

NASA Astrophysics Data System (ADS)

Oliveira, A. S.; Baker, P. A.; Silva, C. G.; Dwyer, G. S.; Rigsby, C. A.; Chiessi, C. M.

2016-12-01

The western Atlantic equatorial margin has been recognized as an important part of global climate change. It is responsible for the transfer of moisture to South America and, heat and fresh water to the northern hemisphere. It might hold answers to past and present global climate. We reconstructed the last 1.6 million years of the paleoclimatic record of the Tropical South American to assess a long period of oceanic and atmospheric variability, which still remains unknown to science. Paleoclimate reconstructions of the Tropical South American are determined on a sediment core located on the Brazilian continental slope. High-resolution XRF analyses of Fe, Ti, K and Ca are used to define the paleohydrologic evolution. Here we present elemental ratios of Ti/Ca and Fe/K, to determine variability in Tropical South America. Differences in sediment input observed on Fe/K and Ti/Ca ratios suggest periods of increased chemical weathering and precipitation. Comparison of our data with the Cariaco basin Molybdenum (Mo) records, suggests that the Intertropical Convergence Zone (ITCZ) is triggering wet periods on Tropical South America, distinguishing a clear North-South anti-phase over the last 600 ka. Southward displacement of the ITCZ in the Mid-Pleistocene Transition, indicates changes in the variability mode of the ITCZ N-S excursion, modulating the precipitation over Tropical South America. We also show that extensive northward migration of Antarctic Polar Front induces a drastic change in the Tropical South America hydrological system, triggering long periods of drought, potentially driven by cooler sea surface temperature of the South Atlantic. This study is funded by Capes- IODP 38/2014 and the Duke University.

Antioxidant Properties of Brazilian Tropical Fruits by Correlation between Different Assays

PubMed Central

Pereira Lima, Giuseppina Pace; Fabris, Sabrina

2013-01-01

Four different assays (the Folin-Ciocalteu, DPPH, enzymatic method, and inhibitory activity on lipid peroxidation) based on radically different physicochemical principles and normally used to determine the antioxidant activity of food have been confronted and utilized to investigate the antioxidant activity of fruits originated from Brazil, with particular attention to more exotic and less-studied species (jurubeba, Solanum paniculatum; pequi, Caryocar brasiliense; pitaya, Hylocereus undatus; siriguela, Spondias purpurea; umbu, Spondias tuberosa) in order to (i) verify the correlations between results obtained by the different assays, with the final purpose to obtain more reliable results avoiding possible measuring-method linked mistakes and (ii) individuate the more active fruit species. As expected, the different methods give different responses, depending on the specific assay reaction. Anyhow all results indicate high antioxidant properties for siriguela and jurubeba and poor values for pitaya, umbu, and pequi. Considering that no marked difference of ascorbic acid content has been detected among the different fruits, experimental data suggest that antioxidant activities of the investigated Brazilian fruits are poorly correlated with this molecule, principally depending on their total polyphenolic content. PMID:24106692

Seagrass-Mediated Phosphorus and Iron Solubilization in Tropical Sediments

PubMed Central

2017-01-01

Tropical seagrasses are nutrient-limited owing to the strong phosphorus fixation capacity of carbonate-rich sediments, yet they form densely vegetated, multispecies meadows in oligotrophic tropical waters. Using a novel combination of high-resolution, two-dimensional chemical imaging of O2, pH, iron, sulfide, calcium, and phosphorus, we found that tropical seagrasses are able to mobilize the essential nutrients iron and phosphorus in their rhizosphere via multiple biogeochemical pathways. We show that tropical seagrasses mobilize phosphorus and iron within their rhizosphere via plant-induced local acidification, leading to dissolution of carbonates and release of phosphate, and via local stimulation of microbial sulfide production, causing reduction of insoluble Fe(III) oxyhydroxides to dissolved Fe(II) with concomitant phosphate release into the rhizosphere porewater. These nutrient mobilization mechanisms have a direct link to seagrass-derived radial O2 loss and secretion of dissolved organic carbon from the below-ground tissue into the rhizosphere. Our demonstration of seagrass-derived rhizospheric phosphorus and iron mobilization explains why seagrasses are widely distributed in oligotrophic tropical waters. PMID:29149570

Tropical rainforest response to marine sky brightening climate engineering

NASA Astrophysics Data System (ADS)

Muri, Helene; Niemeier, Ulrike; Kristjánsson, Jón Egill

2015-04-01

Tropical forests represent a major atmospheric carbon dioxide sink. Here the gross primary productivity (GPP) response of tropical rainforests to climate engineering via marine sky brightening under a future scenario is investigated in three Earth system models. The model response is diverse, and in two of the three models, the tropical GPP shows a decrease from the marine sky brightening climate engineering. Partial correlation analysis indicates precipitation to be important in one of those models, while precipitation and temperature are limiting factors in the other. One model experiences a reversal of its Amazon dieback under marine sky brightening. There, the strongest partial correlation of GPP is to temperature and incoming solar radiation at the surface. Carbon fertilization provides a higher future tropical rainforest GPP overall, both with and without climate engineering. Salt damage to plants and soils could be an important aspect of marine sky brightening.

Genotoxic and mutagenic properties of Bauhinia platypetala extract, a traditional Brazilian medicinal plant.

PubMed

Santos, Francisco José Borges Dos; Moura, Dinara Jaqueline; Péres, Valéria Flores; Sperotto, Angelo Regis de Moura; Caramão, Elina Bastos; Cavalcante, Ana Amélia de Carvalho Melo; Saffi, Jenifer

2012-12-18

Bauhinia platypetala Burch. is a traditionally used Brazilian medicinal plant, although no evidence in the literature substantiates the safety of its use. The aim of this study was to investigate the safety of the ethanolic extract and the ethereal fraction of B. platypetala leaves. The identification of chemical compounds from the B. platypetala ethanolic extract and its ethereal fraction was performed by GC/MS and ESI-MS/MS. The plant's toxicological, cytotoxic, mutagenic and genotoxic properties were determined in Saccharomyces cerevisiae strains and V79 cell culture by survival assays and comet assay. The major compound identified in the B. platypetala ethanolic extract is palmitic acid, kaempferitirin and quercitrin, while the B. platypetala ethereal fraction was found to be rich in phytol, gamma-sitosterol and vitamin E. Moreover, the results indicated that the B. platypetala ethanolic extract has an anti-oxidative effect against H(2)O(2) in yeast. In addition, the B. platypetala ethanolic extract did not induce mutagenic effects on the S. cerevisiae N123 strain, but the ethereal fraction of B. platypetala at higher concentrations (250-500 μg/mL) induced cytotoxicity and mutagenicity. A slight cytotoxic effect was observed in mammalian V79 cells; however, both the B. platypetala ethanolic extract and its ethereal fraction were able to induce DNA strand breaks in V79 cells, as detected by the alkaline comet assay. The B. platypetala ethanolic extract has antioxidant action and showed absence of mutagenic effects in yeast S. cerevisiae. On the other hand B. platypetala ethereal fraction is mutagenic and does not show antioxidant activity in yeast. In mammalian cells B. platypetala ethanolic extract and it's ethereal fraction induce cyotoxic and genotoxic action. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Tropical savannas and dry forests.

PubMed

Pennington, R Toby; Lehmann, Caroline E R; Rowland, Lucy M

2018-05-07

In the tropics, research, conservation and public attention focus on rain forests, but this neglects that half of the global tropics have a seasonally dry climate. These regions are home to dry forests and savannas (Figures 1 and 2), and are the focus of this Primer. The attention given to rain forests is understandable. Their high species diversity, sheer stature and luxuriance thrill biologists today as much as they did the first explorers in the Age of Discovery. Although dry forest and savanna may make less of a first impression, they support a fascinating diversity of plant strategies to cope with stress and disturbance including fire, drought and herbivory. Savannas played a fundamental role in human evolution, and across Africa and India they support iconic megafauna. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effects of three pesticides on the avoidance behavior of earthworms in laboratory tests performed under temperate and tropical conditions.

PubMed

Garcia, Marcos; Römbke, Jörg; de Brito, Marcus Torres; Scheffczyk, Adam

2008-05-01

Little research has been performed on the impact of pesticides on earthworms under tropical conditions. Taking into consideration the often-limited resources in tropical countries, simple screening tests are needed. Therefore, it was investigated whether three pesticides relevant for the Brazilian Amazon (benomyl, carbendazim, lambda-cyhalothrin) affect the avoidance behavior of the earthworm Eisenia fetida. The tests were performed for two days according to ISO guideline 17512 but were adapted to tropical conditions (i.e. test substrate, test organism and temperature). The results indicate that this test gives reproducible and reliable results. Toxicity values (NOEC, EC50) are lower than those determined in 14 day-acute mortality tests and are approximately in the same range such as those found in 56 day-chronic reproduction tests with the same earthworm species, which were performed in parallel. Therefore, the use of the earthworm avoidance tests is recommended as a screening tool for the risk assessment of pesticides.

Parasitoid Wasps in Flower Heads of Asteraceae in the Brazilian Cerrado: Taxonomical Composition and Determinants of Diversity.

PubMed

Nascimento, A R; Almeida-Neto, M; Almeida, A M; Fonseca, C R; Lewinsohn, T M; Penteado-Dias, A M

2014-08-01

This study provides the first survey of the parasitoid fauna reared in flower heads of Asteraceae in the Brazilian cerrado. We investigated the relative importance of herbivore richness and plant species commonness to differences in parasitoid species richness among the plant species. A total of 15,372 specimens from 192 morphospecies belonging to 103 genera of Hymenoptera were reared from the flower heads of 74 Asteraceae species. Chalcidoidea and Ichneumonoidea were the most common superfamilies, with Eulophidae and Braconidae as the main families of parasitoid wasps. Singletons and doubletons accounted for 45% of total parasitoid species richness. The number of parasitoid species per plant species ranged from 1 to 67, and the variation in parasitoid species richness among plants was mainly explained by the number of sites in which the plants were recorded. This study shows that there is a highly diversified fauna of Hymenoptera parasitoids associated with flower heads of Asteraceae in the Brazilian cerrado. Our findings suggest that the accumulation of parasitoid species on plants is mainly determined by the regional commonness of plant species rather than the number of herbivore species associated with the plants.

Sensitivity of tropical carbon to climate change constrained by carbon dioxide variability.

PubMed

Cox, Peter M; Pearson, David; Booth, Ben B; Friedlingstein, Pierre; Huntingford, Chris; Jones, Chris D; Luke, Catherine M

2013-02-21

The release of carbon from tropical forests may exacerbate future climate change, but the magnitude of the effect in climate models remains uncertain. Coupled climate-carbon-cycle models generally agree that carbon storage on land will increase as a result of the simultaneous enhancement of plant photosynthesis and water use efficiency under higher atmospheric CO(2) concentrations, but will decrease owing to higher soil and plant respiration rates associated with warming temperatures. At present, the balance between these effects varies markedly among coupled climate-carbon-cycle models, leading to a range of 330 gigatonnes in the projected change in the amount of carbon stored on tropical land by 2100. Explanations for this large uncertainty include differences in the predicted change in rainfall in Amazonia and variations in the responses of alternative vegetation models to warming. Here we identify an emergent linear relationship, across an ensemble of models, between the sensitivity of tropical land carbon storage to warming and the sensitivity of the annual growth rate of atmospheric CO(2) to tropical temperature anomalies. Combined with contemporary observations of atmospheric CO(2) concentration and tropical temperature, this relationship provides a tight constraint on the sensitivity of tropical land carbon to climate change. We estimate that over tropical land from latitude 30° north to 30° south, warming alone will release 53 ± 17 gigatonnes of carbon per kelvin. Compared with the unconstrained ensemble of climate-carbon-cycle projections, this indicates a much lower risk of Amazon forest dieback under CO(2)-induced climate change if CO(2) fertilization effects are as large as suggested by current models. Our study, however, also implies greater certainty that carbon will be lost from tropical land if warming arises from reductions in aerosols or increases in other greenhouse gases.

Plants with possible psychoactive effects used by the Krahô Indians, Brazil.

PubMed

Rodrigues, Eliana; Carlini, E A

2006-12-01

In spite of the richness of the Brazilian biodiversity, no phytomedicines have been developed from this flora with the purpose of being used in psychiatric treatments. The objective of the present study was to document the use of plants with possible psychoactive effects in rituals performed by the Krahô Indians, who live in the cerrado savannahs biome in the central region of Brazil. Also, the present data were compared with the data obtained during a review of the literature on the use of psychoactive plants by 25 Brazilian indigenous groups. The study was carried out during two years of fieldwork during which anthropological and botanical methods were employed. Seven local shamans were interviewed and they indicated 98 formulas, consisting of 45 plant species that appear to have psychoactive properties and were used in 25 different treatments. Some of the psychoactive properties were "prevention of madness", "stimulant effect", "tranquilizing effect", "prevention of tremors", "longer sleeping period", "open mind" and "induction of sleep". This article also describes the review of literature, which recorded 58 plants that may have psychoactive effects used by 25 Brazilian Indian cultures. The treatment of psychological/psychiatric disorders based on the plants used by the Krahô Indians is very rich. It is also observed among other Brazilian indigenous groups. Future phytochemical and pharmacological studies on these plants may develop new medicines to treat psychiatric disorders.

Arbuscular mycorrhizal fungi in Mimosa tenuiflora (Willd.) Poir from Brazilian semi-arid.

PubMed

de Souza, Tancredo Augusto Feitosa; Rodriguez-Echeverría, Susana; de Andrade, Leonaldo Alves; Freitas, Helena

2016-01-01

Many plant species from Brazilian semi-arid present arbuscular mycorrhizal fungi (AMF) in their rhizosphere. These microorganisms play a key role in the establishment, growth, survival of plants and protection against drought, pathogenic fungi and nematodes. This study presents a quantitative analysis of the AMF species associated with Mimosa tenuiflora, an important native plant of the Caatinga flora. AMF diversity, spore abundance and root colonization were estimated in seven sampling locations in the Ceará and Paraíba States, during September of 2012. There were significant differences in soil properties, spore abundance, percentage of root colonization, and AMF diversity among sites. Altogether, 18 AMF species were identified, and spores of the genera Acaulospora, Claroideoglomus, Dentiscutata, Entrophospora, Funneliformis, Gigaspora, Glomus, Racocetra, Rhizoglomus and Scutellospora were observed. AMF species diversity and their spore abundance found in M. tenuiflora rhizosphere shown that this native plant species is an important host plant to AMF communities from Brazilian semi-arid region. We concluded that: (a) during the dry period and in semi-arid conditions, there is a high spore production in M. tenuiflora root zone; and (b) soil properties, as soil pH and available phosphorous, affect AMF species diversity, thus constituting key factors for the similarity/dissimilarity of AMF communities in the M. tenuiflora root zone among sites. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Seasonal Variation of Ozone in the Tropical Lower Stratosphere: Southern Tropics are Different from Northern Tropics

NASA Technical Reports Server (NTRS)

Stolarski, Richard S.; Waugh, Darryn W.; Wang, Lei,; Oman, Luke D.; Douglass, Anne R.; Newman, Paul A.

2014-01-01

We examine the seasonal behavior of ozone by using measurements from various instruments including ozonesondes, Aura Microwave Limb Sounder, and Stratospheric Aerosol and Gas Experiment II. We find that the magnitude of the annual variation in ozone, as a percentage of the mean ozone, exhibits a maximum at or slightly above the tropical tropopause. The maximum is larger in the northern tropics than in the southern tropics, and the annual maximum of ozone in the southern tropics occurs 2 months later than that in the northern tropics, in contrast to usual assumption that the tropics can be treated as a horizontally homogeneous region. The seasonal cycles of ozone and other species in this part of the lower stratosphere result from a combination of the seasonal variation of the Brewer-Dobson circulation and the seasonal variation of tropical and midlatitude mixing. In the Northern Hemisphere, the impacts of upwelling and mixing between the tropics and midlatitudes on ozone are in phase and additive. In the Southern Hemisphere, they are not in phase. We apply a tropical leaky pipe model independently to each hemisphere to examine the relative roles of upwelling and mixing in the northern and southern tropical regions. Reasonable assumptions of the seasonal variation of upwelling and mixing yield a good description of the seasonal magnitude and phase in both the southern and northern tropics. The differences in the tracers and transport between the northern and southern tropical stratospheres suggest that the paradigm of well-mixed tropics needs to be revised to consider latitudinal variations within the tropics.

Tropical Convection's Roles in Tropical Tropopause Cirrus

NASA Technical Reports Server (NTRS)

Boehm, Matthew T.; Starr, David OC.; Verlinde, Johannes; Lee, Sukyoung

2002-01-01

The results presented here show that tropical convection plays a role in each of the three primary processes involved in the in situ formation of tropopause cirrus. First, tropical convection transports moisture from the surface into the upper troposphere. Second, tropical convection excites Rossby waves that transport zonal momentum toward the ITCZ, thereby generating rising motion near the equator. This rising motion helps transport moisture from where it is detrained from convection to the cold-point tropopause. Finally, tropical convection excites vertically propagating tropical waves (e.g. Kelvin waves) that provide one source of large-scale cooling near the cold-point tropopause, leading to tropopause cirrus formation.

Wood CO2 efflux in a primary tropical rain forest

Treesearch

Molly A. Cavaleri; Steven F. Oberbauer; Michael G. Ryan

2006-01-01

The balance between photosynthesis and plant respiration in tropical forests may substantially affect the global carbon cycle. Woody tissue CO2 efflux is a major component of total plant respiration, but estimates of ecosystem-scale rates are uncertain because of poor sampling in the upper canopy and across landscapes. To overcome these problems, we used a portable...

Tropical forests: present status and future outlook.

PubMed

Myers, N

1991-09-01

Tropical forests still cover almost 8 million km squared of the humid tropics but they are being destroyed at ever-more rapid rates. In 1989, the area deforested amounted to 142,200 km squared, or nearly 90% more than in 1979. Thus, whereas the 1989 amounted total to 1.8% of the remaining biome, the proportion could well continue to rise for the foreseeable future, until there is little forest in just a few decades. Deforestati on patterns are far from even throughout the biome. In much of the Southeast and Southern Asia, East and West Africa, and Central America, there is likely to be little forest left by the year 2000 or shortly thereafter. But in the Zaire basin, western Brazilian Amazonia, and the Guyana highlands, sizeable expanses of forest could persist a good while longer. The main agent of deforestation in the 'shifted cultivator' or displaced peasant, who, responding to land hunger and general lack of rural development in traditional farming areas of countries concerned, feels there is no alternative but to adopt a slash-and-burn lifestyle in forestlands. This person is now accounting for at least 60% of deforestation, a rapidly expanding proportion. However, he receives far less policy attention than the commercial logger, the cattle rancher, and other agents of deforestation.

Urgent need for warming experiments in tropical forests

USGS Publications Warehouse

Calaveri, Molly A.; Reed, Sasha C.; Smith, W. Kolby; Wood, Tana E.

2015-01-01

Although tropical forests account for only a fraction of the planet's terrestrial surface, they exchange more carbon dioxide with the atmosphere than any other biome on Earth, and thus play a disproportionate role in the global climate. In the next 20 years, the tropics will experience unprecedented warming, yet there is exceedingly high uncertainty about their potential responses to this imminent climatic change. Here, we prioritize research approaches given both funding and logistical constraints in order to resolve major uncertainties about how tropical forests function and also to improve predictive capacity of earth system models. We investigate overall model uncertainty of tropical latitudes and explore the scientific benefits and inevitable trade-offs inherent in large-scale manipulative field experiments. With a Coupled Model Intercomparison Project Phase 5 analysis, we found that model variability in projected net ecosystem production was nearly 3 times greater in the tropics than for any other latitude. Through a review of the most current literature, we concluded that manipulative warming experiments are vital to accurately predict future tropical forest carbon balance, and we further recommend the establishment of a network of comparable studies spanning gradients of precipitation, edaphic qualities, plant types, and/or land use change. We provide arguments for long-term, single-factor warming experiments that incorporate warming of the most biogeochemically active ecosystem components (i.e. leaves, roots, soil microbes). Hypothesis testing of underlying mechanisms should be a priority, along with improving model parameterization and constraints. No single tropical forest is representative of all tropical forests; therefore logistical feasibility should be the most important consideration for locating large-scale manipulative experiments. Above all, we advocate for multi-faceted research programs, and we offer arguments for what we consider the most

Urgent need for warming experiments in tropical forests.

PubMed

Cavaleri, Molly A; Reed, Sasha C; Smith, W Kolby; Wood, Tana E

2015-06-01

Although tropical forests account for only a fraction of the planet's terrestrial surface, they exchange more carbon dioxide with the atmosphere than any other biome on Earth, and thus play a disproportionate role in the global climate. In the next 20 years, the tropics will experience unprecedented warming, yet there is exceedingly high uncertainty about their potential responses to this imminent climatic change. Here, we prioritize research approaches given both funding and logistical constraints in order to resolve major uncertainties about how tropical forests function and also to improve predictive capacity of earth system models. We investigate overall model uncertainty of tropical latitudes and explore the scientific benefits and inevitable trade-offs inherent in large-scale manipulative field experiments. With a Coupled Model Intercomparison Project Phase 5 analysis, we found that model variability in projected net ecosystem production was nearly 3 times greater in the tropics than for any other latitude. Through a review of the most current literature, we concluded that manipulative warming experiments are vital to accurately predict future tropical forest carbon balance, and we further recommend the establishment of a network of comparable studies spanning gradients of precipitation, edaphic qualities, plant types, and/or land use change. We provide arguments for long-term, single-factor warming experiments that incorporate warming of the most biogeochemically active ecosystem components (i.e. leaves, roots, soil microbes). Hypothesis testing of underlying mechanisms should be a priority, along with improving model parameterization and constraints. No single tropical forest is representative of all tropical forests; therefore logistical feasibility should be the most important consideration for locating large-scale manipulative experiments. Above all, we advocate for multi-faceted research programs, and we offer arguments for what we consider the most

In vitro propagation of tropical hardwood tree species — A review (2001-2011)

Treesearch

Paula M. Pijut; Rochelle R. Beasley; Shaneka S. Lawson; Kaitlin J. Palla; Micah E. Stevens; Ying Wang

2012-01-01

Tropical hardwood tree species are important economically and ecologically, and play a significant role in the biodiversity of plant and animal species within an ecosystem. There are over 600 species of tropical timbers in the world, many of which are commercially valuable in the international trade of plywood, roundwood, sawnwood, and veneer. Many of these tree...

Death from drought in tropical forests is triggered by hydraulics not carbon starvation

NASA Astrophysics Data System (ADS)

Rowland, L.; da Costa, A. C. L.; Galbraith, D. R.; Oliveira, R. S.; Binks, O. J.; Oliveira, A. A. R.; Pullen, A. M.; Doughty, C. E.; Metcalfe, D. B.; Vasconcelos, S. S.; Ferreira, L. V.; Malhi, Y.; Grace, J.; Mencuccini, M.; Meir, P.

2015-12-01

Drought threatens tropical rainforests over seasonal to decadal timescales, but the drivers of tree mortality following drought remain poorly understood. It has been suggested that reduced availability of non-structural carbohydrates (NSC) critically increases mortality risk through insufficient carbon supply to metabolism (‘carbon starvation’). However, little is known about how NSC stores are affected by drought, especially over the long term, and whether they are more important than hydraulic processes in determining drought-induced mortality. Using data from the world’s longest-running experimental drought study in tropical rainforest (in the Brazilian Amazon), we test whether carbon starvation or deterioration of the water-conducting pathways from soil to leaf trigger tree mortality. Biomass loss from mortality in the experimentally droughted forest increased substantially after >10 years of reduced soil moisture availability. The mortality signal was dominated by the death of large trees, which were at a much greater risk of hydraulic deterioration than smaller trees. However, we find no evidence that the droughted trees suffered carbon starvation, as their NSC concentrations were similar to those of non-droughted trees, and growth rates did not decline in either living or dying trees. Our results indicate that hydraulics, rather than carbon starvation, triggers tree death from drought in tropical rainforest.

Death from drought in tropical forests is triggered by hydraulics not carbon starvation.

PubMed

Rowland, L; da Costa, A C L; Galbraith, D R; Oliveira, R S; Binks, O J; Oliveira, A A R; Pullen, A M; Doughty, C E; Metcalfe, D B; Vasconcelos, S S; Ferreira, L V; Malhi, Y; Grace, J; Mencuccini, M; Meir, P

2015-12-03

Drought threatens tropical rainforests over seasonal to decadal timescales, but the drivers of tree mortality following drought remain poorly understood. It has been suggested that reduced availability of non-structural carbohydrates (NSC) critically increases mortality risk through insufficient carbon supply to metabolism ('carbon starvation'). However, little is known about how NSC stores are affected by drought, especially over the long term, and whether they are more important than hydraulic processes in determining drought-induced mortality. Using data from the world's longest-running experimental drought study in tropical rainforest (in the Brazilian Amazon), we test whether carbon starvation or deterioration of the water-conducting pathways from soil to leaf trigger tree mortality. Biomass loss from mortality in the experimentally droughted forest increased substantially after >10 years of reduced soil moisture availability. The mortality signal was dominated by the death of large trees, which were at a much greater risk of hydraulic deterioration than smaller trees. However, we find no evidence that the droughted trees suffered carbon starvation, as their NSC concentrations were similar to those of non-droughted trees, and growth rates did not decline in either living or dying trees. Our results indicate that hydraulics, rather than carbon starvation, triggers tree death from drought in tropical rainforest.

Emissions of biogenic volatile organic compounds and subsequent photochemical production of secondary organic aerosol in mesocosm studies of temperate and tropical plant species

NASA Astrophysics Data System (ADS)

Wyche, K. P.; Ryan, A. C.; Hewitt, C. N.; Alfarra, M. R.; McFiggans, G.; Carr, T.; Monks, P. S.; Smallbone, K. L.; Capes, G.; Hamilton, J. F.; Pugh, T. A. M.; MacKenzie, A. R.

2014-06-01

Silver birch (Betula pendula) and three Southeast Asian tropical plant species (Ficus cyathistipula, Ficus benjamina and Caryota millis) from the pantropical fig and palm genera were grown in a purpose-built and environment-controlled whole-tree chamber. The volatile organic compounds emitted from these trees were characterised and fed into a linked photochemical reaction chamber where they underwent photooxidation under a range of controlled conditions (RH ∼65-89%, VOC/NOx ∼3-9 and NOx ∼2 ppbV). Both the gas phase and the aerosol phase of the reaction chamber were monitored in detail using a comprehensive suite of on-line and off-line, chemical and physical measurement techniques. Silver birch was found to be a high monoterpene and sesquiterpene, but low isoprene emitter, and its emissions were observed to produce measureable amounts of SOA via both nucleation and condensation onto pre-existing seed aerosol (YSOA 26-39%). In contrast, all three tropical species were found to be high isoprene emitters with trace emissions of monoterpenes and sesquiterpenes. In tropical plant experiments without seed aerosol there was no measurable SOA nucleation, but aerosol mass was shown to increase when seed aerosol was present. Although principally isoprene emitting, the aerosol mass produced from tropical fig was mostly consistent (i.e., in 78 out of 120 aerosol mass calculations using plausible parameter sets of various precursor specific yields) with condensation of photooxidation products of the minor VOCs co-emitted; no significant aerosol yield from condensation of isoprene oxidation products was required in the interpretations of the experimental results. This finding is in line with previous reports of organic aerosol loadings consistent with production from minor biogenic VOCs co-emitted with isoprene in principally-isoprene emitting landscapes in Southeast Asia. Moreover, in general the amount of aerosol mass produced from the emissions of the principally

Emissions of biogenic volatile organic compounds and subsequent photochemical production of secondary organic aerosol in mesocosm studies of temperate and tropical plant species

NASA Astrophysics Data System (ADS)

Wyche, K. P.; Ryan, A. C.; Hewitt, C. N.; Alfarra, M. R.; McFiggans, G.; Carr, T.; Monks, P. S.; Smallbone, K. L.; Capes, G.; Hamilton, J. F.; Pugh, T. A. M.; MacKenzie, A. R.

2014-12-01

Silver birch (Betula pendula) and three Southeast Asian tropical plant species (Ficus cyathistipula, Ficus benjamina and Caryota millis) from the pantropical fig and palm genera were grown in a purpose-built and environment-controlled whole-tree chamber. The volatile organic compounds emitted from these trees were characterised and fed into a linked photochemical reaction chamber where they underwent photo-oxidation under a range of controlled conditions (relative humidity or RH ~65-89%, volatile organic compound-to-NOx or VOC / NOx ~3-9 and NOx ~2 ppbV). Both the gas phase and the aerosol phase of the reaction chamber were monitored in detail using a comprehensive suite of on-line and off-line chemical and physical measurement techniques. Silver birch was found to be a high monoterpene and sesquiterpene but low isoprene emitter, and its emissions were observed to produce measurable amounts of secondary organic aerosol (SOA) via both nucleation and condensation onto pre-existing seed aerosol (YSOA 26-39%). In contrast, all three tropical species were found to be high isoprene emitters with trace emissions of monoterpenes and sesquiterpenes. In tropical plant experiments without seed aerosol there was no measurable SOA nucleation, but aerosol mass was shown to increase when seed aerosol was present. Although principally isoprene emitting, the aerosol mass produced from tropical fig was mostly consistent (i.e. in 78 out of 120 aerosol mass calculations using plausible parameter sets of various precursor specific yields) with condensation of photo-oxidation products of the minor volatile organic compounds (VOCs) co-emitted; no significant aerosol yield from condensation of isoprene oxidation products was required in the interpretations of the experimental results. This finding is in line with previous reports of organic aerosol loadings consistent with production from minor biogenic VOCs co-emitted with isoprene in principally isoprene-emitting landscapes in Southeast

Soil nutrients influence spatial distributions of tropical tree species.

PubMed

John, Robert; Dalling, James W; Harms, Kyle E; Yavitt, Joseph B; Stallard, Robert F; Mirabello, Matthew; Hubbell, Stephen P; Valencia, Renato; Navarrete, Hugo; Vallejo, Martha; Foster, Robin B

2007-01-16

The importance of niche vs. neutral assembly mechanisms in structuring tropical tree communities remains an important unsettled question in community ecology [Bell G (2005) Ecology 86:1757-1770]. There is ample evidence that species distributions are determined by soils and habitat factors at landscape (<10(4) km(2)) and regional scales. At local scales (<1 km(2)), however, habitat factors and species distributions show comparable spatial aggregation, making it difficult to disentangle the importance of niche and dispersal processes. In this article, we test soil resource-based niche assembly at a local scale, using species and soil nutrient distributions obtained at high spatial resolution in three diverse neotropical forest plots in Colombia (La Planada), Ecuador (Yasuni), and Panama (Barro Colorado Island). Using spatial distribution maps of >0.5 million individual trees of 1,400 species and 10 essential plant nutrients, we used Monte Carlo simulations of species distributions to test plant-soil associations against null expectations based on dispersal assembly. We found that the spatial distributions of 36-51% of tree species at these sites show strong associations to soil nutrient distributions. Neutral dispersal assembly cannot account for these plant-soil associations or the observed niche breadths of these species. These results indicate that belowground resource availability plays an important role in the assembly of tropical tree communities at local scales and provide the basis for future investigations on the mechanisms of resource competition among tropical tree species.

Role of Brazilian Amazon protected areas in climate change mitigation

PubMed Central

Soares-Filho, Britaldo; Moutinho, Paulo; Nepstad, Daniel; Anderson, Anthony; Rodrigues, Hermann; Garcia, Ricardo; Dietzsch, Laura; Merry, Frank; Bowman, Maria; Hissa, Letícia; Silvestrini, Rafaella; Maretti, Cláudio

2010-01-01

Protected areas (PAs) now shelter 54% of the remaining forests of the Brazilian Amazon and contain 56% of its forest carbon. However, the role of these PAs in reducing carbon fluxes to the atmosphere from deforestation and their associated costs are still uncertain. To fill this gap, we analyzed the effect of each of 595 Brazilian Amazon PAs on deforestation using a metric that accounts for differences in probability of deforestation in areas of pairwise comparison. We found that the three major categories of PA (indigenous land, strictly protected, and sustainable use) showed an inhibitory effect, on average, between 1997 and 2008. Of 206 PAs created after the year 1999, 115 showed increased effectiveness after their designation as protected. The recent expansion of PAs in the Brazilian Amazon was responsible for 37% of the region's total reduction in deforestation between 2004 and 2006 without provoking leakage. All PAs, if fully implemented, have the potential to avoid 8.0 ± 2.8 Pg of carbon emissions by 2050. Effectively implementing PAs in zones under high current or future anthropogenic threat offers high payoffs for reducing carbon emissions, and as a result should receive special attention in planning investments for regional conservation. Nevertheless, this strategy demands prompt and predictable resource streams. The Amazon PA network represents a cost of US$147 ± 53 billion (net present value) for Brazil in terms of forgone profits and investments needed for their consolidation. These costs could be partially compensated by an international climate accord that includes economic incentives for tropical countries that reduce their carbon emissions from deforestation and forest degradation. PMID:20505122

Role of Brazilian Amazon protected areas in climate change mitigation.

PubMed

Soares-Filho, Britaldo; Moutinho, Paulo; Nepstad, Daniel; Anderson, Anthony; Rodrigues, Hermann; Garcia, Ricardo; Dietzsch, Laura; Merry, Frank; Bowman, Maria; Hissa, Letícia; Silvestrini, Rafaella; Maretti, Cláudio

2010-06-15

Protected areas (PAs) now shelter 54% of the remaining forests of the Brazilian Amazon and contain 56% of its forest carbon. However, the role of these PAs in reducing carbon fluxes to the atmosphere from deforestation and their associated costs are still uncertain. To fill this gap, we analyzed the effect of each of 595 Brazilian Amazon PAs on deforestation using a metric that accounts for differences in probability of deforestation in areas of pairwise comparison. We found that the three major categories of PA (indigenous land, strictly protected, and sustainable use) showed an inhibitory effect, on average, between 1997 and 2008. Of 206 PAs created after the year 1999, 115 showed increased effectiveness after their designation as protected. The recent expansion of PAs in the Brazilian Amazon was responsible for 37% of the region's total reduction in deforestation between 2004 and 2006 without provoking leakage. All PAs, if fully implemented, have the potential to avoid 8.0 +/- 2.8 Pg of carbon emissions by 2050. Effectively implementing PAs in zones under high current or future anthropogenic threat offers high payoffs for reducing carbon emissions, and as a result should receive special attention in planning investments for regional conservation. Nevertheless, this strategy demands prompt and predictable resource streams. The Amazon PA network represents a cost of US$147 +/- 53 billion (net present value) for Brazil in terms of forgone profits and investments needed for their consolidation. These costs could be partially compensated by an international climate accord that includes economic incentives for tropical countries that reduce their carbon emissions from deforestation and forest degradation.

Five thousand years of tropical lake sediment DNA records from Benin

NASA Astrophysics Data System (ADS)

Bremond, L.; Favier, C.; Ficetola, G. F.; Tossou, M. G.; Akouégninou, A.; Gielly, L.; Giguet-Covex, C.; Oslisly, R.; Salzmann, U.

2017-08-01

Until now, sedimentary DNA (sedDNA) studies have only focused on cold and temperate regions were DNA is relatively well preserved. Consequently, the tropics, where vegetation is hyperdiverse and natural archives are rare, have been neglected and deserve attention. In this study, we used next-generation sequencing to barcode sedDNA from Lake Sele, localized in the tropical lowlands of Benin (Africa), and compared the taxonomic diversity detected by DNA analyses with pollen assemblages. Plant sedDNA was successfully amplified from 33 of the 34 successfully extracted samples. In total, 43 taxa were identified along the 5000 years spanned by the sediment: 22 taxa were identified at the family level and 21 at the genus level. The plant diversity recovered through sedDNA from Lake Sele showed a specific local signal and limited overlapping with pollen. Introduced plants, grown and cultivated close to the water, such as sweet potato, were also well recorded by sedDNA. It appears, therefore, to be a promising approach to studying past diversity in tropical regions, and could help in tracking the introduction and history of agriculture. This is the first time this method has been used in the field of domestication and dissemination of several specific crops, and the results are very encouraging.

Predicting of biomass in Brazilian tropical dry forest: a statistical evaluation of generic equations.

PubMed

Lima, Robson B DE; Alves, Francisco T; Oliveira, Cinthia P DE; Silva, José A A DA; Ferreira, Rinaldo L C

2017-01-01

Dry tropical forests are a key component in the global carbon cycle and their biomass estimates depend almost exclusively of fitted equations for multi-species or individual species data. Therefore, a systematic evaluation of statistical models through validation of estimates of aboveground biomass stocks is justifiable. In this study was analyzed the capacity of generic and specific equations obtained from different locations in Mexico and Brazil, to estimate aboveground biomass at multi-species levels and for four different species. Generic equations developed in Mexico and Brazil performed better in estimating tree biomass for multi-species data. For Poincianella bracteosa and Mimosa ophthalmocentra, only the Sampaio and Silva (2005) generic equation was the most recommended. These equations indicate lower tendency and lower bias, and biomass estimates for these equations are similar. For the species Mimosa tenuiflora, Aspidosperma pyrifolium and for the genus Croton the specific regional equations are more recommended, although the generic equation of Sampaio and Silva (2005) is not discarded for biomass estimates. Models considering gender, families, successional groups, climatic variables and wood specific gravity should be adjusted, tested and the resulting equations should be validated at both local and regional levels as well as on the scales of tropics with dry forest dominance.

Warfarin Safety: A Cross-Sectional Study of the Factors Associated with the Consumption of Medicinal Plants in a Brazilian Anticoagulation Clinic.

PubMed

Leite, Paula Mendonça; de Freitas, Aline A; Mourão, Aline de O Magalhães; Martins, Maria A P; Castilho, Rachel O

2018-06-01

The aim of this study was to analyze factors associated with the consumption of medicinal plants by patients being treated with warfarin in a Brazilian anticoagulation clinic and to study the safety of medicinal plant use in patients on warfarin therapy. The study was performed as an observational cross-sectional analysis. Study participants were outpatients on long-term warfarin therapy for at least 2 months for atrial fibrillation or prosthetic cardiac valves. Interviews were carried out concerning information about the habits of medicinal herb consumption, and logistic regression analysis was performed to identify factors associated with the consumption of herbs. The scientific names of the medicinal plants were identified to search for information on the effects on the hemostasis of the interactions between the medicinal herbs reported and warfarin. The mean age of the 273 patients included was 60.8 years; 58.7% were women. Medicinal plants were used by 67% of the participants. No association between demographic and clinical data and the use of medicinal plants was identified. Patients reported a total of 64 different plants, primarily consumed in the form of tea. The plants were mainly used to treat respiratory tract and central nervous system disorders. About 40% of the plants cited have been reported to potentially interfere with the anticoagulation therapy, principally by potentiating the effects of warfarin, which could, increase the risk of bleeding. The use of medicinal plants was highly common and widespread in patients receiving warfarin as an anticoagulation therapy. Univariate analysis of variables associated with the consumption of herbs showed no statistically significant difference in the consumption of medicinal plants for any of the sociodemographic and clinical data. The medicinal plants that were reportedly consumed by the patients could affect hemostasis. This study reinforces the need for further studies evaluating the habits of patients

The Brazilian developments on the Regional Atmospheric Modeling System (BRAMS 5.2): an integrated environmental model tuned for tropical areas

NASA Astrophysics Data System (ADS)

Freitas, Saulo R.; Panetta, Jairo; Longo, Karla M.; Rodrigues, Luiz F.; Moreira, Demerval S.; Rosário, Nilton E.; Silva Dias, Pedro L.; Silva Dias, Maria A. F.; Souza, Enio P.; Freitas, Edmilson D.; Longo, Marcos; Frassoni, Ariane; Fazenda, Alvaro L.; Silva, Cláudio M. Santos e.; Pavani, Cláudio A. B.; Eiras, Denis; França, Daniela A.; Massaru, Daniel; Silva, Fernanda B.; Santos, Fernando C.; Pereira, Gabriel; Camponogara, Gláuber; Ferrada, Gonzalo A.; Campos Velho, Haroldo F.; Menezes, Isilda; Freire, Julliana L.; Alonso, Marcelo F.; Gácita, Madeleine S.; Zarzur, Maurício; Fonseca, Rafael M.; Lima, Rafael S.; Siqueira, Ricardo A.; Braz, Rodrigo; Tomita, Simone; Oliveira, Valter; Martins, Leila D.

2017-01-01

We present a new version of the Brazilian developments on the Regional Atmospheric Modeling System (BRAMS), in which different previous versions for weather, chemistry, and carbon cycle were unified in a single integrated modeling system software. This new version also has a new set of state-of-the-art physical parameterizations and greater computational parallel and memory usage efficiency. The description of the main model features includes several examples illustrating the quality of the transport scheme for scalars, radiative fluxes on surface, and model simulation of rainfall systems over South America at different spatial resolutions using a scale aware convective parameterization. Additionally, the simulation of the diurnal cycle of the convection and carbon dioxide concentration over the Amazon Basin, as well as carbon dioxide fluxes from biogenic processes over a large portion of South America, are shown. Atmospheric chemistry examples show the model performance in simulating near-surface carbon monoxide and ozone in the Amazon Basin and the megacity of Rio de Janeiro. For tracer transport and dispersion, the model capabilities to simulate the volcanic ash 3-D redistribution associated with the eruption of a Chilean volcano are demonstrated. The gain of computational efficiency is described in some detail. BRAMS has been applied for research and operational forecasting mainly in South America. Model results from the operational weather forecast of BRAMS on 5 km grid spacing in the Center for Weather Forecasting and Climate Studies, INPE/Brazil, since 2013 are used to quantify the model skill of near-surface variables and rainfall. The scores show the reliability of BRAMS for the tropical and subtropical areas of South America. Requirements for keeping this modeling system competitive regarding both its functionalities and skills are discussed. Finally, we highlight the relevant contribution of this work to building a South American community of model

The Brazilian Developments on the Regional Atmospheric Modeling System (BRAMS 5.2): An Integrated Environmental Model Tuned for Tropical Areas

NASA Technical Reports Server (NTRS)

Freitas, Saulo R.; Panetta, Jairo; Longo, Karla M.; Rodrigues, Luiz F.; Moreira, Demerval S.; Rosario, Nilton E.; Silva Dias, Pedro L.; Silva Dias, Maria A. F.; Souza, Enio P.; Freitas, Edmilson D.;

β-Diversity of Functional Groups of Woody Plants in a Tropical Dry Forest in Yucatan

PubMed Central

López-Martínez, Jorge Omar; Sanaphre-Villanueva, Lucía; Dupuy, Juan Manuel; Hernández-Stefanoni, José Luis; Meave, Jorge Arturo; Gallardo-Cruz, José Alberto

2013-01-01

Two main theories have attempted to explain variation in plant species composition (β-diversity). Niche theory proposes that most of the variation is related to environment (environmental filtering), whereas neutral theory posits that dispersal limitation is the main driver of β-diversity. In this study, we first explored how α- and β-diversity of plant functional groups defined by growth form (trees, shrubs and lianas, which represent different strategies of resource partitioning), and dispersal syndrome (autochory, anemochory and zoochory, which represent differences in dispersal limitation) vary with successional age and topographic position in a tropical dry forest. Second, we examined the effects of environmental, spatial, and spatially-structured environmental factors on β-diversity of functional groups; we used the spatial structure of sampling sites as a proxy for dispersal limitation, and elevation, soil properties and forest stand age as indicators of environmental filtering. We recorded 200 species and 22,245 individuals in 276 plots; 120 species were trees, 41 shrubs and 39 lianas. We found that β-diversity was highest for shrubs, intermediate for lianas and lowest for trees, and was slightly higher for zoochorous than for autochorous and anemochorous species. All three dispersal syndromes, trees and shrubs varied in composition among vegetation classes (successional age and topographic position), whilst lianas did not. β-diversity was influenced mostly by proxies of environmental filtering, except for shrubs, for which the influence of dispersal limitation was more important. Stand age and topography significantly influenced α-diversity across functional groups, but showed a low influence on β-diversity –possibly due to the counterbalancing effect of resprouting on plant distribution and composition. Our results show that considering different plant functional groups reveals important differences in both α- and β-diversity patterns and

Implementation of the Brazilian National Repository - RBMN Project - 13008

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

Cassia Oliveira de Tello, Cledola

2013-07-01

Ionizing radiation in Brazil is used in electricity generation, medicine, industry, agriculture and for research and development purposes. All these activities can generate radioactive waste. At this point, in Brazil, the use of nuclear energy and radioisotopes justifies the construction of a national repository for radioactive wastes of low and intermediate-level. According to Federal Law No. 10308, Brazilian National Commission for Nuclear Energy (CNEN) is responsible for designing and constructing the intermediate and final storages for radioactive wastes. Additionally, a restriction on the construction of Angra 3 is that the repository is under construction until its operation start, attaining somemore » requirements of the Brazilian Environmental Regulator (IBAMA). Besides this NPP, in the National Energy Program is previewed the installation of four more plants, by 2030. In November 2008, CNEN launched the Project RBMN (Repository for Low and Intermediate-Level Radioactive Wastes), which aims at the implantation of a National Repository for disposal of low and intermediate-level of radiation wastes. This Project has some aspects that are unique in the Brazilian context, especially referring to the time between its construction and the end of its institutional period. This time is about 360 years, when the area will be released for unrestricted uses. It means that the Repository must be safe and secure for more than three hundred years, which is longer than half of the whole of Brazilian history. This aspect is very new for the Brazilian people, bringing a new dimension to public acceptance. Another point is this will be the first repository in South America, bringing a real challenge for the continent. The current status of the Project is summarized. (authors)« less

Transcriptome profiling of low temperature-treated cassava apical shoots showed dynamic responses of tropical plant to cold stress

PubMed Central

2012-01-01

Background Cassava is an important tropical root crop adapted to a wide range of environmental stimuli such as drought and acid soils. Nevertheless, it is an extremely cold-sensitive tropical species. Thus far, there is limited information about gene regulation and signalling pathways related to the cold stress response in cassava. The development of microarray technology has accelerated the study of global transcription profiling under certain conditions. Results A 60-mer oligonucleotide microarray representing 20,840 genes was used to perform transcriptome profiling in apical shoots of cassava subjected to cold at 7°C for 0, 4 and 9 h. A total of 508 transcripts were identified as early cold-responsive genes in which 319 sequences had functional descriptions when aligned with Arabidopsis proteins. Gene ontology annotation analysis identified many cold-relevant categories, including 'Response to abiotic and biotic stimulus', 'Response to stress', 'Transcription factor activity', and 'Chloroplast'. Various stress-associated genes with a wide range of biological functions were found, such as signal transduction components (e.g., MAP kinase 4), transcription factors (TFs, e.g., RAP2.11), and reactive oxygen species (ROS) scavenging enzymes (e.g., catalase 2), as well as photosynthesis-related genes (e.g., PsaL). Seventeen major TF families including many well-studied members (e.g., AP2-EREBP) were also involved in the early response to cold stress. Meanwhile, KEGG pathway analysis uncovered many important pathways, such as 'Plant hormone signal transduction' and 'Starch and sucrose metabolism'. Furthermore, the expression changes of 32 genes under cold and other abiotic stress conditions were validated by real-time RT-PCR. Importantly, most of the tested stress-responsive genes were primarily expressed in mature leaves, stem cambia, and fibrous roots rather than apical buds and young leaves. As a response to cold stress in cassava, an increase in transcripts and

Starch grains reveal early root crop horticulture in the Panamanian tropical forest.

PubMed

Piperno, D R; Ranere, A J; Holst, I; Hansell, P

2000-10-19

Native American populations are known to have cultivated a large number of plants and domesticated them for their starch-rich underground organs. Suggestions that the likely source of many of these crops, the tropical forest, was an early and influential centre of plant husbandry have long been controversial because the organic remains of roots and tubers are poorly preserved in archaeological sediments from the humid tropics. Here we report the occurrence of starch grains identifiable as manioc (Manihot esculenta Crantz), yams (Dioscorea sp.) and arrowroot (Maranta arundinacea L.) on assemblages of plant milling stones from preceramic horizons at the Aguadulce Shelter, Panama, dated between 7,000 and 5,000 years before present (BP). The artefacts also contain maize starch (Zea mays L.), indicating that early horticultural systems in this region were mixtures of root and seed crops. The data provide the earliest direct evidence for root crop cultivation in the Americas, and support an ancient and independent emergence of plant domestication in the lowland Neotropical forest.

Micro-organisms behind the pollination scenes: microbial imprint on floral nectar sugar variation in a tropical plant community.

PubMed

Canto, A; Herrera, C M

2012-11-01

Variation in the composition of floral nectar reflects intrinsic plant characteristics as well as the action of extrinsic factors. Micro-organisms, particularly yeasts, represent one extrinsic factor that inhabit the nectar of animal-pollinated flowers worldwide. In this study a 'microbial imprint hypothesis' is formulated and tested, in which it is proposed that natural community-wide variation in nectar sugar composition will partly depend on the presence of yeasts in flowers. Occurrence and density of yeasts were studied microscopically in single-flower nectar samples of 22 animal-pollinated species from coastal xeric and sub-humid tropical habitats of the Yucatán Peninsula, Mexico. Nectar sugar concentration and composition were concurrently determined on the same samples using high-performance liquid chromatography (HPLC) methods. Microscopical examination of nectar samples revealed the presence of yeasts in nearly all plant species (21 out of 22 species) and in about half of the samples examined (51·8 % of total, all species combined). Plant species and individuals differed significantly in nectar sugar concentration and composition, and also in the incidence of nectar yeasts. After statistically controlling for differences between plant species and individuals, nectar yeasts still accounted for a significant fraction of community-wide variance in all nectar sugar parameters considered. Significant yeast × species interactions on sugar parameters revealed that plant species differed in the nectar sugar correlates of variation in yeast incidence. The results support the hypothesis that nectar yeasts impose a detectable imprint on community-wide variation in nectar sugar composition and concentration. Since nectar sugar features influence pollinator attraction and plant reproduction, future nectar studies should control for yeast presence and examine the extent to which microbial signatures on nectar characteristics ultimately have some influence on

Micro-organisms behind the pollination scenes: microbial imprint on floral nectar sugar variation in a tropical plant community

PubMed Central

Canto, A.; Herrera, C. M.

2012-01-01

Background and Aims Variation in the composition of floral nectar reflects intrinsic plant characteristics as well as the action of extrinsic factors. Micro-organisms, particularly yeasts, represent one extrinsic factor that inhabit the nectar of animal-pollinated flowers worldwide. In this study a ‘microbial imprint hypothesis’ is formulated and tested, in which it is proposed that natural community-wide variation in nectar sugar composition will partly depend on the presence of yeasts in flowers. Methods Occurrence and density of yeasts were studied microscopically in single-flower nectar samples of 22 animal-pollinated species from coastal xeric and sub-humid tropical habitats of the Yucatán Peninsula, Mexico. Nectar sugar concentration and composition were concurrently determined on the same samples using high-performance liquid chromatography (HPLC) methods. Key Results Microscopical examination of nectar samples revealed the presence of yeasts in nearly all plant species (21 out of 22 species) and in about half of the samples examined (51·8 % of total, all species combined). Plant species and individuals differed significantly in nectar sugar concentration and composition, and also in the incidence of nectar yeasts. After statistically controlling for differences between plant species and individuals, nectar yeasts still accounted for a significant fraction of community-wide variance in all nectar sugar parameters considered. Significant yeast × species interactions on sugar parameters revealed that plant species differed in the nectar sugar correlates of variation in yeast incidence. Conclusions The results support the hypothesis that nectar yeasts impose a detectable imprint on community-wide variation in nectar sugar composition and concentration. Since nectar sugar features influence pollinator attraction and plant reproduction, future nectar studies should control for yeast presence and examine the extent to which microbial signatures on nectar

[Regenerative morphological traits in a woody species community in Tumbesian tropical dry forest].

PubMed

Romero-Saritama, José Miguel; Pérez-Rúuz, César

2016-06-01

The study of functional morphological traits enables us to know fundamental aspects of the dynamics of plant communities in local and global habitats. Regenerative morphological traits play an important role in defining plant history and ecological behavior. Seed and fruit characteristics determine to a large extent the patterns for dispersal, germination, establishment and seedling recruitment a given species exhibits on its natural habitat. Despite their prominent role, seed and fruit traits have been poorly studied at the community level of woody plant species in neo-tropical dry forests. In the present study we aimed at i) evaluate the functional role of morphological traits of seeds, fruits and embryo in woody plant species; ii) determine which are the morphological patterns present in seeds collected from the community of woody species that occur in neo-tropical dry forests; and iii) compare woody plant species seed mass values comparatively between neo-tropical dry and tropical forests. To do so, mature seeds were collected from 79 plant species that occur in the Tumbesian forest of Southwest Ecuador. The studied species included the 42 and 37 most representative tree and shrubbery species of the Tumbesian forest respectively. A total of 18 morphological traits (seven quantitative and 11 qualitative) were measured and evaluated in the seeds, fruits and embryos of the selected species, and we compared the seeds mass with other forest types. Our results showed a huge heterogeneity among traits values in the studied species. Seed mass, volume and number were the traits that vary the most at the community level, i.e. seed length ranged from 1.3 to 39 mm, and seed width from 0.6 to 25 mm. Only six embryo types were found among the 79 plant species. In 40 % of the cases, fully developed inverted embryos with large and thick cotyledons to store considerable amount of nutrients were recorded. We concluded that highly variable and functionally complementary

Antibacterial, antioxidant, and anticholinesterase activities of plant seed extracts from Brazilian semiarid region.

PubMed

Farias, Davi Felipe; Souza, Terezinha Maria; Viana, Martônio Ponte; Soares, Bruno Marques; Cunha, Arcelina Pacheco; Vasconcelos, Ilka Maria; Ricardo, Nágila Maria Pontes Silva; Ferreira, Paulo Michel Pinheiro; Melo, Vânia Maria Maciel; Carvalho, Ana Fontenele Urano

2013-01-01

The antimicrobial, antioxidant, and anticholinesterase activities of ethanolic seed extracts of twenty-one plant species from Brazilian semiarid region were investigated. The extracts were tested for antimicrobial activity against six bacteria strains and three yeasts. Six extracts presented activity against the Gram (-) organism Salmonella choleraesuis and the Gram (+) organisms Staphylococcus aureus and Bacillus subtilis. The MIC values ranged from 4.96 to 37.32 mg/mL. The Triplaris gardneriana extract presented activity against the three species, with MIC values 18.8, 13.76, and 11.15 mg/mL, respectively. Five extracts presented antioxidant activity, with EC50 values ranging from 69.73 μ g/mL (T. gardneriana) to 487.51 μ g/mL (Licania rigida). For the anticholinesterase activity, eleven extracts were capable of inhibiting the enzyme activity. From those, T. gardneriana, Parkia platycephala and Connarus detersus presented the best activities, with inhibition values of 76.7, 71.5, and 91.9%, respectively. The extracts that presented antimicrobial activity were tested for hemolytic assay against human A, B, and O blood types and rabbit blood. From those, only the Myracrodruon urundeuva extract presented activity (about 20% of hemolysis at the lowest tested concentration, 1.9 µg/mL). Infrared spectroscopy of six representative extracts attested the presence of tannins, polyphenols, and flavonoids, which was confirmed by a qualitative phytochemical assay.

Employing airborne multispectral digital imagery to map Brazilian pepper infestation in south Texas.

USDA-ARS?s Scientific Manuscript database

A study was conducted in south Texas to determine the feasibility of using airborne multispectral digital imagery for differentiating the invasive plant Brazilian pepper (Schinus terebinthifolius) from other cover types. Imagery obtained in the visible, near infrared, and mid infrared regions of th...

High yielding tropical energy crops for bioenergy production: Effects of plant components, harvest years and locations on biomass composition.

PubMed

Surendra, K C; Ogoshi, Richard; Zaleski, Halina M; Hashimoto, Andrew G; Khanal, Samir Kumar

2018-03-01

The composition of lignocellulosic feedstock, which depends on crop type, crop management, locations and plant parts, significantly affects the conversion efficiency of biomass into biofuels and biobased products. Thus, this study examined the composition of different parts of two high yielding tropical energy crops, Energycane and Napier grass, collected across three locations and years. Significantly higher fiber content was found in the leaves of Energycane than stems, while fiber content was significantly higher in the stems than the leaves of Napier grass. Similarly, fiber content was higher in Napier grass than Energycane. Due to significant differences in biomass composition between the plant parts within a crop type, neither biological conversion, including anaerobic digestion, nor thermochemical pretreatment alone is likely to efficiently convert biomass components into biofuels and biobased products. However, combination of anaerobic digestion with thermochemical conversion technologies could efficiently utilize biomass components in generating biofuels and biobased products. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biogenic VOC Emissions from Tropical Landscapes

NASA Astrophysics Data System (ADS)

Guenther, A.; Greenberg, J.; Harley, P.; Otter, L.; Vanni Gatti, L.; Baker, B.

2003-04-01

Biogenic VOC have an important role in determining the chemical composition of atmosphere. As a result, these compounds are important for visibility, biogeochemical cycling, climate and radiative forcing, and the health of the biosphere. Tropical landscapes are estimated to release about 80% of total global biogenic VOC emissions but have been investigated to lesser extent than temperate regions. Tropical VOC emissions are particularly important due to the strong vertical transport and the rapid landuse change that is occurring there. This presentation will provide an overview of field measurements of biogenic VOC emissions from tropical landscapes in Amazonia (Large-scale Biosphere-atmosphere experiment in Amazonia, LBA) Central (EXPRESSO) and Southern (SAFARI 2000) Africa, Asia and Central America. Flux measurement methods include leaf-scale (enclosure measurements), canopy-scale (above canopy tower measurements), landscape-scale (tethered balloon), and regional-scale (aircraft measurements) observations. Typical midday isoprene emission rates for different landscapes vary by more than a factor of 20 with the lowest emissions observed from degraded forests. Emissions of alpha-pinene vary by a similar amount with the highest emissions associated with landscapes dominated by light dependent monoterpene emitting plants. Isoprene emissions tend to be higher for neotropical forests (Amazon and Costa Rica) in comparison to Africa and Asian tropical forests but considerable differences are observed within regions. Strong seasonal variations were observed in both the Congo and the Amazon rainforests with peak emissions during the dry seasons. Substantial emissions of light dependent monoterpenes, methanol and acetone are characteristic of at least some tropical landscapes.

The Brazilian Honeybee

ERIC Educational Resources Information Center

Michener, Charles D.

1973-01-01

Discusses the unusually aggressive Brazilian honeybee, which exhibits many of the attributes of its African antecedants. Describes its abundance and distribution, behaviorial characteristics, future spread, and the potential impact of the Brazilian bee in North America. (JR)

Effect of the environment on the secondary metabolic profile of Tithonia diversifolia: a model for environmental metabolomics of plants.

PubMed

Sampaio, Bruno Leite; Edrada-Ebel, RuAngelie; Da Costa, Fernando Batista

2016-07-07

Tithonia diversifolia is an invasive weed commonly found in tropical ecosystems. In this work, we investigate the influence of different abiotic environmental factors on the plant's metabolite profile by multivariate statistical analyses of spectral data deduced by UHPLC-DAD-ESI-HRMS and NMR methods. Different plant part samples of T. diversifolia which included leaves, stems, roots, and inflorescences were collected from two Brazilian states throughout a 24-month period, along with the corresponding monthly environmental data. A metabolomic approach employing concatenated LC-MS and NMR data was utilised for the first time to study the relationships between environment and plant metabolism. A seasonal pattern was observed for the occurrence of metabolites that included sugars, sesquiterpenes lactones and phenolics in the leaf and stem parts, which can be correlated to the amount of rainfall and changes in temperature. The distribution of the metabolites in the inflorescence and root parts were mainly affected by variation of some soil nutrients such as Ca, Mg, P, K and Cu. We highlight the environment-metabolism relationship for T. diversifolia and the combined analytical approach to obtain reliable data that contributed to a holistic understanding of the influence of abiotic environmental factors on the production of metabolites in various plant parts.

Seasonal leaf dynamics across a tree density gradient in a Brazilian savanna.

Treesearch

William A. Hoffmann; Edson Rangel da Silva; Gustavo C. Machado; Sandra Bucci; Fabian G. Scholz; Guillermo Goldstein; Frederick C. Meinzer

2005-01-01

Interactions between trees and grasses that influence leaf area index (LAI) have important consequences for savanna ecosystem processes through their controls on water, carbon, and energy fluxes as well as fire regimes. We measured LAI, of the groundlayer (herbaceous and woody plants 1-m tall), in the Brazilian...

Isolation and enzyme bioprospection of endophytic bacteria associated with plants of Brazilian mangrove ecosystem.

PubMed

Castro, Renata A; Quecine, Maria Carolina; Lacava, Paulo T; Batista, Bruna D; Luvizotto, Danice M; Marcon, Joelma; Ferreira, Anderson; Melo, Itamar S; Azevedo, João L

2014-01-01

The mangrove ecosystem is a coastal tropical biome located in the transition zone between land and sea that is characterized by periodic flooding, which confers unique and specific environmental conditions on this biome. In these ecosystems, the vegetation is dominated by a particular group of plant species that provide a unique environment harboring diverse groups of microorganisms, including the endophytic microorganisms that are the focus of this study. Because of their intimate association with plants, endophytic microorganisms could be explored for biotechnologically significant products, such as enzymes, proteins, antibiotics and others. Here, we isolated endophytic microorganisms from two mangrove species, Rhizophora mangle and Avicennia nitida, that are found in streams in two mangrove systems in Bertioga and Cananéia, Brazil. Bacillus was the most frequently isolated genus, comprising 42% of the species isolated from Cananéia and 28% of the species from Bertioga. However, other common endophytic genera such as Pantoea, Curtobacterium and Enterobacter were also found. After identifying the isolates, the bacterial communities were evaluated for enzyme production. Protease activity was observed in 75% of the isolates, while endoglucanase activity occurred in 62% of the isolates. Bacillus showed the highest activity rates for amylase and esterase and endoglucanase. To our knowledge, this is the first reported diversity analysis performed on endophytic bacteria obtained from the branches of mangrove trees and the first overview of the specific enzymes produced by different bacterial genera. This work contributes to our knowledge of the microorganisms and enzymes present in mangrove ecosystems.

Chronic human disturbance affects plant trait distribution in a seasonally dry tropical forest

NASA Astrophysics Data System (ADS)

Sfair, Julia C.; de Bello, Francesco; de França, Thaysa Q.; Baldauf, Cristina; Tabarelli, Marcelo

2018-02-01

The effects of human disturbance on biodiversity can be mediated by environmental conditions, such as water availability, climate and nutrients. In general, disturbed, dry or nutrient-depleted soils areas tend to have lower taxonomic diversity. However, little is known about how these environmental conditions affect functional composition and intraspecific variability in tropical dry forests. We studied a seasonally dry tropical forest (SDTF) under chronic anthropogenic disturbance (CAD) along rainfall and soil nutrient gradients to understand how these factors influence the taxonomic and functional composition. Specifically we evaluated two aspects of CAD, wood extraction and livestock pressure (goat and cattle grazing), along soil fertility and rainfall gradients on shrub and tree traits, considering species turnover and intraspecific variability. In addition, we also tested how the traits of eight populations of the most frequent species are affected by wood extraction, livestock pressure, rainfall and soil fertility. In general, although CAD and environmental gradients affected each trait of the most widespread species differently, the most abundant species also had a greater variation of traits. Considering species turnover, wood extraction is associated with species with a smaller leaf area and lower investment in leaf mass, probably due to the indirect effects of this disturbance type on the vegetation, i.e. the removal of branches and woody debris clears the vegetation, favouring species that minimize water loss. Livestock pressure, on the other hand, affected intraspecific variation: the herbivory caused by goats and cattle promoted individuals which invest more in wood density and leaf mass. In this case, the change of functional composition observed is a direct effect of the disturbance, such as the decrease of palatable plant abundance by goat and cattle herbivory. In synthesis, CAD, rainfall and soil fertility can affect trait distribution at community

SRTM-DEM and Landsat ETM+ data for mapping tropical dry forest cover and biodiversity assessment in Nicaragua

Treesearch

S.E. Sesnie; S.E. Hagell; S.M. Otterstrom; C.L. Chambers; B.G. Dickson

2008-01-01

Tropical dry and deciduous forest comprises as much as 42% of the world’s tropical forests, but has received far less attention than forest in wet tropical areas. Land use change threatens to greatly reduce the extent of dry forest that is known to contain high levels of plant and animal diversity. Forest fragmentation may further endanger arboreal mammals that play...

Oligarchic forests of economic plants in amazonia: utilization and conservation of an important tropical resource.

PubMed

Peters, C M; Balick, M J; Kahn, F; Anderson, A B

1989-12-01

Tropical forests dominated by only one or two tree species occupy tens of millions of hectares in Ammonia In many cases, the dominant species produce fruits, seeds, or oils of economic importance. Oligarchic (Gr. oligo = few, archic = dominated or ruled by) forests of six economic species, i. e., Euterpe oleracea, Grias peruviana, Jessenia bataua, Mauritia flexuosa, Myrciaria dubia, and Orbignya phalerata, were studied in Brazil and Peru Natural populations of these species contain from 100 to 3,000 conspecific adult trees/ha and produce up to 11.1 metric tons of fruit/hd/yr. These plant populations are utilized and occasionally managed, by rural inhabitants in the region. Periodic fruit harvests, if properly controlled have only a minimal impact on forest structure and function, yet can generate substantial economic returns Market-oriented extraction of the fruits produced by oligarchic forests appears to represent a promising alternative for reconciling the development and conservation of Amazonian forests.

Defaunation affects carbon storage in tropical forests

PubMed Central

Bello, Carolina; Galetti, Mauro; Pizo, Marco A.; Magnago, Luiz Fernando S.; Rocha, Mariana F.; Lima, Renato A. F.; Peres, Carlos A.; Ovaskainen, Otso; Jordano, Pedro

2015-01-01

Carbon storage is widely acknowledged as one of the most valuable forest ecosystem services. Deforestation, logging, fragmentation, fire, and climate change have significant effects on tropical carbon stocks; however, an elusive and yet undetected decrease in carbon storage may be due to defaunation of large seed dispersers. Many large tropical trees with sizeable contributions to carbon stock rely on large vertebrates for seed dispersal and regeneration, however many of these frugivores are threatened by hunting, illegal trade, and habitat loss. We used a large data set on tree species composition and abundance, seed, fruit, and carbon-related traits, and plant-animal interactions to estimate the loss of carbon storage capacity of tropical forests in defaunated scenarios. By simulating the local extinction of trees that depend on large frugivores in 31 Atlantic Forest communities, we found that defaunation has the potential to significantly erode carbon storage even when only a small proportion of large-seeded trees are extirpated. Although intergovernmental policies to reduce carbon emissions and reforestation programs have been mostly focused on deforestation, our results demonstrate that defaunation, and the loss of key ecological interactions, also poses a serious risk for the maintenance of tropical forest carbon storage. PMID:26824067

[Neotropical plant morphology].

PubMed

Pérez-García, Blanca; Mendoza, Aniceto

2002-01-01

An analysis on plant morphology and the sources that are important to the morphologic interpretations is done. An additional analysis is presented on all published papers in this subject by the Revista de Biología Tropical since its foundation, as well as its contribution to the plant morphology development in the neotropics.

A gradient of auxin and auxin-dependent transcription precedes tropic growth responses.

PubMed

Esmon, C Alex; Tinsley, Amanda G; Ljung, Karin; Sandberg, Goran; Hearne, Leonard B; Liscum, Emmanuel

2006-01-03

Plants, although sessile, can reorient growth axes in response to changing environmental conditions. Phototropism and gravitropism represent adaptive growth responses induced by changes in light direction and growth axis orientation relative to gravitational direction, respectively. The nearly 80-year-old Cholodny-Went theory [Went, F. W. & Thimann, K. V. (1937) Phytohormones (Macmillan, New York)] predicts that formation of a gradient of the plant morphogen auxin is central to the establishment of tropic curvature. Loss of tropic responses in seedling stems of Arabidopsis thaliana mutants lacking the auxin-regulated transcriptional activator NPH4/ARF7 has further suggested that a gradient of gene expression represents an essential output from the auxin gradient. Yet the molecular identities of such output components, which are likely to encode proteins directly involved in growth control, have remained elusive. Here we report the discovery of a suite of tropic stimulus-induced genes in Brassica oleracea that are responsive to an auxin gradient and exhibit morphologically graded expression concomitant with, or before, observable curvature responses. These results provide compelling molecular support for the Cholodny-Went theory and suggest that morphologically graded transcription represents an important mechanism for interpreting tropically stimulated gradients of auxin. Intriguingly, two of the tropic stimulus-induced genes, EXPA1 and EXPA8, encode enzymes involved in cell wall extension, a response prerequisite for differential growth leading to curvatures, and are up-regulated before curvature in the flank that will elongate. This observation suggests that morphologically graded transcription likely leads to the graded expression of proteins whose activities can directly regulate the establishment and modulation of tropic curvatures.

Community patterns of tropical tree phenology derived from Unmanned Aerial Vehicle images: intra- and interspecific variation, association with species plant traits, and response to interannual climate variation

NASA Astrophysics Data System (ADS)

Bohlman, Stephanie; Rifai, Sami; Park, John; Dandois, Jonathan; Muller-Landau, Helene

2017-04-01

Phenology is a key life history trait of plant species and critical driver of ecosystem processes. There is strong evidence that phenology is shifting in temperate ecosystems in response to climate change, but tropical forest phenology remains poorly quantified and understood. A key challenge is that tropical forests contain hundreds of plant species with a wide variety of phenological patterns, which makes it difficult to collect sufficient ground-based field data to characterize individual tropical tree species phenologies. Satellite-based observations, an important source of phenology data in northern latitudes, are hindered by frequent cloud cover in the tropics. To quantify phenology over a large number of individuals and species, we collected bi-weekly images from unmanned aerial vehicles (UAVs) in the well-studied 50-ha forest inventory plot on Barro Colorado Island, Panama. The objective of this study is to quantify inter- and intra-specific responses of tropical tree leaf phenology to environmental variation over large spatial scales and identify key environmental variables and physiological mechanisms underpinning phenological variation. Between October 2014 and December 2015 and again in May 2015, we collected a total of 35 sets of UAV images, each with continuous coverage of the 50-ha plot, where every tree ≥ 1 cm DBH is mapped. UAV imagery was corrected for exposure, orthorectified, and then processed to extract spectral, texture, and image information for individual tree crowns, which was then used as inputs for a machine learning algorithm that successfully predicted the percentages of leaf, branch, and flower cover for each tree crown (r2=0.76 between observed and predicted percent branch cover for individual tree crowns). We then quantified cumulative annual deciduousness for each crown by fitting a non-parametric curve of flexible shape to its predicted percent branch time series and calculated the area under the curve. We obtained the species

Plant tropisms: providing the power of movement to a sessile organism.

PubMed

Esmon, C Alex; Pedmale, Ullas V; Liscum, Emmanuel

2005-01-01

In an attempt to compensate for their sessile nature, plants have developed growth responses to deal with the copious and rapid changes in their environment. These responses are known as tropisms and they are marked by a directional growth response that is the result of differential cellular growth and development in response to an external stimulation such as light, gravity or touch. While the mechanics of tropic growth and subsequent development have been the topic of debate for more than a hundred years, only recently have researchers been able to make strides in understanding how plants perceive and respond to tropic stimulations, thanks in large part to mutant analysis and recent advances in genomics. This paper focuses on the recent advances in four of the best-understood tropic responses and how each affects plant growth and development: phototropism, gravitropism, thigmotropism and hydrotropism. While progress has been made in deciphering the events between tropic stimulation signal perception and each characteristic growth response, there are many areas that remain unclear, some of which will be discussed herein. As has become evident, each tropic response pathway exhibits distinguishing characteristics. However, these pathways of tropic perception and response also have overlapping components - a fact that is certainly related to the necessity for pathway integration given the ever-changing environment that surrounds every plant.

Phylobetadiversity among forest types in the Brazilian Atlantic Forest complex.

PubMed

Duarte, Leandro Da Silva; Bergamin, Rodrigo Scarton; Marcilio-Silva, Vinícius; Seger, Guilherme Dubal Dos Santos; Marques, Márcia Cristina Mendes

2014-01-01

Phylobetadiversity is defined as the phylogenetic resemblance between communities or biomes. Analyzing phylobetadiversity patterns among different vegetation physiognomies within a single biome is crucial to understand the historical affinities between them. Based on the widely accepted idea that different forest physiognomies within the Southern Brazilian Atlantic Forest constitute different facies of a single biome, we hypothesize that more recent phylogenetic nodes should drive phylobetadiversity gradients between the different forest types within the Atlantic Forest, as the phylogenetic divergence among those forest types is biogeographically recent. We compiled information from 206 checklists describing the occurrence of shrub/tree species across three different forest physiognomies within the Southern Brazilian Atlantic Forest (Dense, Mixed and Seasonal forests). We analyzed intra-site phylogenetic structure (phylogenetic diversity, net relatedness index and nearest taxon index) and phylobetadiversity between plots located at different forest types, using five different methods differing in sensitivity to either basal or terminal nodes (phylogenetic fuzzy weighting, COMDIST, COMDISTNT, UniFrac and Rao's H). Mixed forests showed higher phylogenetic diversity and overdispersion than the other forest types. Furthermore, all forest types differed from each other in relation phylobetadiversity patterns, particularly when phylobetadiversity methods more sensitive to terminal nodes were employed. Mixed forests tended to show higher phylogenetic differentiation to Dense and Seasonal forests than these latter from each other. The higher phylogenetic diversity and phylobetadiversity levels found in Mixed forests when compared to the others likely result from the biogeographical origin of several taxa occurring in these forests. On one hand, Mixed forests shelter several temperate taxa, like the conifers Araucaria and Podocarpus. On the other hand, tropical groups, like

Phylobetadiversity among Forest Types in the Brazilian Atlantic Forest Complex

PubMed Central

Duarte, Leandro Da Silva; Bergamin, Rodrigo Scarton; Marcilio-Silva, Vinícius; Seger, Guilherme Dubal Dos Santos; Marques, Márcia Cristina Mendes

2014-01-01

Phylobetadiversity is defined as the phylogenetic resemblance between communities or biomes. Analyzing phylobetadiversity patterns among different vegetation physiognomies within a single biome is crucial to understand the historical affinities between them. Based on the widely accepted idea that different forest physiognomies within the Southern Brazilian Atlantic Forest constitute different facies of a single biome, we hypothesize that more recent phylogenetic nodes should drive phylobetadiversity gradients between the different forest types within the Atlantic Forest, as the phylogenetic divergence among those forest types is biogeographically recent. We compiled information from 206 checklists describing the occurrence of shrub/tree species across three different forest physiognomies within the Southern Brazilian Atlantic Forest (Dense, Mixed and Seasonal forests). We analyzed intra-site phylogenetic structure (phylogenetic diversity, net relatedness index and nearest taxon index) and phylobetadiversity between plots located at different forest types, using five different methods differing in sensitivity to either basal or terminal nodes (phylogenetic fuzzy weighting, COMDIST, COMDISTNT, UniFrac and Rao’s H). Mixed forests showed higher phylogenetic diversity and overdispersion than the other forest types. Furthermore, all forest types differed from each other in relation phylobetadiversity patterns, particularly when phylobetadiversity methods more sensitive to terminal nodes were employed. Mixed forests tended to show higher phylogenetic differentiation to Dense and Seasonal forests than these latter from each other. The higher phylogenetic diversity and phylobetadiversity levels found in Mixed forests when compared to the others likely result from the biogeographical origin of several taxa occurring in these forests. On one hand, Mixed forests shelter several temperate taxa, like the conifers Araucaria and Podocarpus. On the other hand, tropical groups

Global change effects on humid tropical forests: Evidence for biogeochemical and biodiversity shifts at an ecosystem scale

NASA Astrophysics Data System (ADS)

Cusack, Daniela F.; Karpman, Jason; Ashdown, Daniel; Cao, Qian; Ciochina, Mark; Halterman, Sarah; Lydon, Scott; Neupane, Avishesh

2016-09-01

Government and international agencies have highlighted the need to focus global change research efforts on tropical ecosystems. However, no recent comprehensive review exists synthesizing humid tropical forest responses across global change factors, including warming, decreased precipitation, carbon dioxide fertilization, nitrogen deposition, and land use/land cover changes. This paper assesses research across spatial and temporal scales for the tropics, including modeling, field, and controlled laboratory studies. The review aims to (1) provide a broad understanding of how a suite of global change factors are altering humid tropical forest ecosystem properties and biogeochemical processes; (2) assess spatial variability in responses to global change factors among humid tropical regions; (3) synthesize results from across humid tropical regions to identify emergent trends in ecosystem responses; (4) identify research and management priorities for the humid tropics in the context of global change. Ecosystem responses covered here include plant growth, carbon storage, nutrient cycling, biodiversity, and disturbance regime shifts. The review demonstrates overall negative effects of global change on all ecosystem properties, with the greatest uncertainty and variability in nutrient cycling responses. Generally, all global change factors reviewed, except for carbon dioxide fertilization, demonstrate great potential to trigger positive feedbacks to global warming via greenhouse gas emissions and biogeophysical changes that cause regional warming. This assessment demonstrates that effects of decreased rainfall and deforestation on tropical forests are relatively well understood, whereas the potential effects of warming, carbon dioxide fertilization, nitrogen deposition, and plant species invasions require more cross-site, mechanistic research to predict tropical forest responses at regional and global scales.

Bioquality Hotspots in the Tropical African Flora.

PubMed

Marshall, Cicely A M; Wieringa, Jan J; Hawthorne, William D

2016-12-05

Identifying areas of high biodiversity is an established way to prioritize areas for conservation [1-3], but global approaches have been criticized for failing to render global biodiversity value at a scale suitable for local management [4-6]. We assembled 3.1 million species distribution records for 40,401 vascular plant species of tropical Africa from sources including plot data, herbarium databases, checklists, and the Global Biodiversity Information Facility (GBIF) and cleaned the records for geographic accuracy and taxonomic consistency. We summarized the global ranges of tropical African plant species into four weighted categories of global rarity called Stars. We applied the Star weights to summaries of species distribution data at fine resolutions to map the bioquality (range-restricted global endemism) of areas [7]. We generated confidence intervals around bioquality scores to account for the remaining uncertainty in the species inventory. We confirm the broad significance of the Horn of Africa, Guinean forests, coastal forests of East Africa, and Afromontane regions for plant biodiversity but also reveal the variation in bioquality within these broad regions and others, particularly at local scales. Our framework offers practitioners a quantitative, scalable, and replicable approach for measuring the irreplaceability of particular local areas for global biodiversity conservation and comparing those areas within their global and regional context. Copyright © 2016 Elsevier Ltd. All rights reserved.

Forest-climate interactions in fragmented tropical landscapes.

PubMed

Laurance, William F

2004-03-29

In the tropics, habitat fragmentation alters forest-climate interactions in diverse ways. On a local scale (less than 1 km), elevated desiccation and wind disturbance near fragment margins lead to sharply increased tree mortality, thus altering canopy-gap dynamics, plant community composition, biomass dynamics and carbon storage. Fragmented forests are also highly vulnerable to edge-related fires, especially in regions with periodic droughts or strong dry seasons. At landscape to regional scales (10-1000 km), habitat fragmentation may have complex effects on forest-climate interactions, with important consequences for atmospheric circulation, water cycling and precipitation. Positive feedbacks among deforestation, regional climate change and fire could pose a serious threat for some tropical forests, but the details of such interactions are poorly understood.

A physiologically-based plant hydraulics scheme for ESMs: impacts of hydraulic trait variability for tropical forests under drought

NASA Astrophysics Data System (ADS)

Christoffersen, B. O.; Xu, C.; Fisher, R.; Fyllas, N.; Gloor, M.; Fauset, S.; Galbraith, D.; Koven, C.; Knox, R. G.; Kueppers, L. M.; Chambers, J. Q.; Meir, P.; McDowell, N. G.

2016-12-01

A major challenge of Earth System Models (ESMs) is to capture the diversity of individual-level responses to changes in water availability. Yet, decades of research in plant physiological ecology have given us a means to quantify central tendencies and variances of plant hydraulic traits. If ESMs possessed the relevant hydrodynamic process structure, these traits could be incorporated into improved predictions of community- and ecosystem-level processes such as tree mortality. We present a model of plant hydraulics in which all parameters are biologically-interpretable and measurable traits, such as turgor loss point πtlp, bulk elastic modulus ɛ, hydraulic capacitance Cft, xylem hydraulic conductivity ks,max, water potential at 50 % loss of conductivity for both xylem (P50,x) and stomata (P50,gs). We applied this scheme to tropical forests by incorporating it into both an individual-based model `Trait Forest Simulator' (TFS) and the `Functionally Assembled Terrestrial Ecosystem Simulator' (FATES; derived from CLM(ED)), and explore the consequences of variability in plant hydraulic traits on simulated leaf water potential, a potentially powerful predictor of tree mortality. We show that, independent of the difference between P50,gs and P50,x, or the hydraulic safety margin (HSM), diversity in hydraulic traits can increase or decrease whole-ecosystem resistance to hydraulic failure, and thus ecosystem-level responses to drought. Key uncertainties remaining concern how coordination and trade-offs in hydraulic traits are parameterized. We conclude that inclusion of such a physiologically-based plant hydraulics scheme in ESMs will greatly improve the capability of ESMs to predict functional trait filtering within ecosystems in responding to environmental change.

Export-oriented deforestation in Mato Grosso: harbinger or exception for other tropical forests?

PubMed

DeFries, Ruth; Herold, Martin; Verchot, Louis; Macedo, Marcia N; Shimabukuro, Yosio

2013-06-05

The Brazilian state of Mato Grosso was a global deforestation hotspot in the early 2000s. Deforested land is used predominantly to produce meat for distal consumption either through cattle ranching or soya bean for livestock feed. Deforestation declined dramatically in the latter part of the decade through a combination of market forces, policies, enforcement and improved monitoring. This study assesses how representative the national-level drivers underlying Mato Grosso's export-oriented deforestation are in other tropical forest countries based on agricultural exports, commercial agriculture and urbanization. We also assess how pervasive the governance and technical monitoring capacity that enabled Mato Grosso's decline in deforestation is in other countries. We find that between 41 and 54 per cent of 2000-2005 deforestation in tropical forest countries (other than Brazil) occurred in countries with drivers similar to Brazil. Very few countries had national-level governance and capacity similar to Brazil. Results suggest that the ecological, hydrological and social consequences of land-use change for export-oriented agriculture as discussed in this Theme Issue were applicable in about one-third of all tropical forest countries in 2000-2005. However, the feasibility of replicating Mato Grosso's success with controlling deforestation is more limited. Production landscapes to support distal consumption similar to Mato Grosso are likely to become more prevalent and are unlikely to follow a land-use transition model with increasing forest cover.

Soil nitrogen levels are linked to decomposition enzyme activities along an urban-remote tropical forest gradient

Treesearch

D. F. Cusack

2013-01-01

Urban areas in tropical regions are expanding rapidly, with significant potential to affect local ecosystem dynamics. In particular, nitrogen (N) availability may increase in urban-proximate forests because of atmospheric N deposition. Unlike temperate forests, many tropical forests on highly weathered soils have high background N availability, so plant growth is...

Leaf litter decomposition rates increase with rising mean annual temperature in Hawaiian tropical montane wet forests

Treesearch

Lori D. Bothwell; Paul C. Selmants; Christian P. Giardina; Creighton M. Litton

2014-01-01

Decomposing litter in forest ecosystems supplies nutrients to plants, carbon to heterotrophic soil microorganisms and is a large source of CO2 to the atmosphere. Despite its essential role in carbon and nutrient cycling, the temperature sensitivityof leaf litter decay in tropical forest ecosystems remains poorly resolved, especially in tropical...

Evaluation of Brazilian biotechnology patent activity from 1975 to 2010.

PubMed

Dias, F; Delfim, F; Drummond, I; Carmo, A O; Barroca, T M; Horta, C C; Kalapothakis, E

2012-08-01

The analysis of patent activity is one methodology used for technological monitoring. In this paper, the activity of biotechnology-related patents in Brazil were analyzed through 30 International Patent Classification (IPC) codes published by the Organization for Economic Cooperation and Development (OECD). We developed a program to analyse the dynamics of the major patent applicants, countries and IPC codes extracted from the Brazilian Patent Office (INPI) database. We also identified Brazilian patent applicants who tried to expand protection abroad via the Patent Cooperation Treaty (PCT). We had access to all patents published online at the INPI from 1975 to July 2010, including 9,791 biotechnology patent applications in Brazil, and 163 PCTs published online at World Intellectual Property Organization (WIPO) from 1997 to December 2010. To our knowledge, there are no other online reports of biotechnology patents previous to the years analyzed here. Most of the biotechnology patents filed in the INPI (10.9%) concerned measuring or testing processes involving nucleic acids. The second and third places belonged to patents involving agro-technologies (recombinant DNA technology for plant cells and new flowering plants, i.e. angiosperms, or processes for obtaining them, and reproduction of flowering plants by tissue culture techniques). The majority of patents (87.2%) were filed by nonresidents, with USA being responsible for 51.7% of all biotechnology patents deposited in Brazil. Analyzing the resident applicants per region, we found a hub in the southeast region of Brazil. Among the resident applicants for biotechnology patents filed in the INPI, 43.5% were from São Paulo, 18.3% were from Rio de Janeiro, and 9.7% were from Minas Gerais. Pfizer, Novartis, and Sanofi were the largest applicants in Brazil, with 339, 288, and 245 biotechnology patents filed, respectively. For residents, the largest applicant was the governmental institution FIOCRUZ (Oswaldo Cruz

Measurement of deforestation in the Brazilian Amazon using satellite remote sensing

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

Skole, D.L.

1992-01-01

Understanding of the role of the biota in the global carbon cycle is limited by an absence of accurate measurements of deforestation rates in the tropics. This study measures the rate and extent of deforestation in the Brazilian Amazon, the largest extant tropical forest biome in the world. The study uses remote sensing measurements of deforestation rates, the area of secondary vegetation, and tabular data to document deforestation. The analysis concludes: (1) AVHRR will greatly overestimate deforestation and be highly variable; the use of a brightness temperature threshold is highly sensitive and unreliable. The upward bias of AVHRR is amore » function of the density of deforestation. (2) Accurate measurement of deforestation requires Landsat TM data, and can be accomplished using low cost visual interpretation of photographic products at 1:250,000 scales. (3) Secondary growth in the Brazilian Amazon represents a large fraction of the total deforested area, and the abandonment of agricultural land is an important land cover transition. Abandonment rates were 70--83% of clearing rates from primary forests. At any one point in time, approximately 30% of the deforested area is in some stage of abandonment, and quite likely nearly all deforested land becomes abandoned after approximately 5 years. (4) Previous estimates of the total area deforested in the Amazon, as well as deforestation rates, have been too high by as much as 4-fold. A complete assessment of the entire Legal Amazon using over 200 Landsat images measures 251 [times] 10[sup 3] km[sup 2] deforestation as of 1988, or approximately 6% of the closed forests of the region. The average annual rate of deforestation between 1978 and 1988 was 18 [times] 10[sup 3] km[sup 2] yr[sup [minus]1]. These findings suggest the estimates of carbon emissions from the Amazon for the late 1980s have been too high, since the area of regrowth is large and rates of deforestation are lower than previously believed.« less

Soil carbon stocks across tropical forests of Panama regulated by base cation effects on fine roots

DOE PAGES

Cusack, Daniela F.; Markesteijn, Lars; Condit, Richard; ...

2018-01-02

We report that tropical forests are the most carbon (C)- rich ecosystems on Earth, containing 25–40% of global terrestrial C stocks. While large-scale quantifi- cation of aboveground biomass in tropical forests has improved recently, soil C dynamics remain one of the largest sources of uncertainty in Earth system models, which inhibits our ability to predict future climate. Globally, soil texture and climate predict B 30% of the variation in soil C stocks, so ecosystem models often predict soil C using measures of aboveground plant growth. However, this approach can underestimate tropical soil C stocks, and has proven inaccurate when comparedmore » with data for soil C in data-rich northern ecosystems. By quantifying soil organic C stocks to 1 m depth for 48 humid tropical forest plots across gradients of rainfall and soil fertility in Panama, we show that soil C does not correlate with common predictors used in models, such as plant biomass or litter production. Instead, a structural equation model including base cations, soil clay content, and rainfall as exogenous factors and root biomass as an endogenous factor predicted nearly 50% of the variation in tropical soil C stocks, indicating a strong indirect effect of base cation availability on tropical soil C storage. Including soil base cations in C cycle models, and thus emphasizing mechanistic links among nutrients, root biomass, and soil C stocks, will improve prediction of climate-soil feedbacks in tropical forests.« less

Soil carbon stocks across tropical forests of Panama regulated by base cation effects on fine roots

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

Cusack, Daniela F.; Markesteijn, Lars; Condit, Richard

We report that tropical forests are the most carbon (C)- rich ecosystems on Earth, containing 25–40% of global terrestrial C stocks. While large-scale quantifi- cation of aboveground biomass in tropical forests has improved recently, soil C dynamics remain one of the largest sources of uncertainty in Earth system models, which inhibits our ability to predict future climate. Globally, soil texture and climate predict B 30% of the variation in soil C stocks, so ecosystem models often predict soil C using measures of aboveground plant growth. However, this approach can underestimate tropical soil C stocks, and has proven inaccurate when comparedmore » with data for soil C in data-rich northern ecosystems. By quantifying soil organic C stocks to 1 m depth for 48 humid tropical forest plots across gradients of rainfall and soil fertility in Panama, we show that soil C does not correlate with common predictors used in models, such as plant biomass or litter production. Instead, a structural equation model including base cations, soil clay content, and rainfall as exogenous factors and root biomass as an endogenous factor predicted nearly 50% of the variation in tropical soil C stocks, indicating a strong indirect effect of base cation availability on tropical soil C storage. Including soil base cations in C cycle models, and thus emphasizing mechanistic links among nutrients, root biomass, and soil C stocks, will improve prediction of climate-soil feedbacks in tropical forests.« less

Utilization of geothermal heat in tropical fruit-drying process

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

Chen, B.H.; Lopez, L.P.; King, R.

1982-10-01

The power plant utilizes only the steam portion of the HGP-A well production. There are approximately 50,000 pounds per hour of 360/sup 0/F water produced (approximately 10 million Btu per hour) and the water is currently not used and is considered a waste. This tremendous resource could very well be used in applications such as food processing, food dehydration and other industrial processing that requires low-grade heat. One of the applications is examined, namely the drying of tropical fruits particularly the papaya. The papaya was chosen for the obvious reason that it is the biggest crop of all fruits producedmore » on the Big Island. A conceptual design of a pilot plant facility capable of processing 1000 pounds of raw papaya per day is included. This facility is designed to provide a geothermally heated dryer to dehydrate papayas or other tropical fruits available on an experimental basis to obtain data such as drying time, optimum drying temperature, etc.« less

The draft genome of tropical fruit durian (Durio zibethinus).

PubMed

Teh, Bin Tean; Lim, Kevin; Yong, Chern Han; Ng, Cedric Chuan Young; Rao, Sushma Ramesh; Rajasegaran, Vikneswari; Lim, Weng Khong; Ong, Choon Kiat; Chan, Ki; Cheng, Vincent Kin Yuen; Soh, Poh Sheng; Swarup, Sanjay; Rozen, Steven G; Nagarajan, Niranjan; Tan, Patrick

2017-11-01

Durian (Durio zibethinus) is a Southeast Asian tropical plant known for its hefty, spine-covered fruit and sulfury and onion-like odor. Here we present a draft genome assembly of D. zibethinus, representing the third plant genus in the Malvales order and first in the Helicteroideae subfamily to be sequenced. Single-molecule sequencing and chromosome contact maps enabled assembly of the highly heterozygous durian genome at chromosome-scale resolution. Transcriptomic analysis showed upregulation of sulfur-, ethylene-, and lipid-related pathways in durian fruits. We observed paleopolyploidization events shared by durian and cotton and durian-specific gene expansions in MGL (methionine γ-lyase), associated with production of volatile sulfur compounds (VSCs). MGL and the ethylene-related gene ACS (aminocyclopropane-1-carboxylic acid synthase) were upregulated in fruits concomitantly with their downstream metabolites (VSCs and ethylene), suggesting a potential association between ethylene biosynthesis and methionine regeneration via the Yang cycle. The durian genome provides a resource for tropical fruit biology and agronomy.

Antibacterial, Antioxidant, and Anticholinesterase Activities of Plant Seed Extracts from Brazilian Semiarid Region

PubMed Central

Farias, Davi Felipe; Souza, Terezinha Maria; Viana, Martônio Ponte; Soares, Bruno Marques; Cunha, Arcelina Pacheco; Vasconcelos, Ilka Maria; Ricardo, Nágila Maria Pontes Silva; Ferreira, Paulo Michel Pinheiro; Melo, Vânia Maria Maciel; Carvalho, Ana Fontenele Urano

2013-01-01

The antimicrobial, antioxidant, and anticholinesterase activities of ethanolic seed extracts of twenty-one plant species from Brazilian semiarid region were investigated. The extracts were tested for antimicrobial activity against six bacteria strains and three yeasts. Six extracts presented activity against the Gram (−) organism Salmonella choleraesuis and the Gram (+) organisms Staphylococcus aureus and Bacillus subtilis. The MIC values ranged from 4.96 to 37.32 mg/mL. The Triplaris gardneriana extract presented activity against the three species, with MIC values 18.8, 13.76, and 11.15 mg/mL, respectively. Five extracts presented antioxidant activity, with EC50 values ranging from 69.73 μg/mL (T. gardneriana) to 487.51 μg/mL (Licania rigida). For the anticholinesterase activity, eleven extracts were capable of inhibiting the enzyme activity. From those, T. gardneriana, Parkia platycephala and Connarus detersus presented the best activities, with inhibition values of 76.7, 71.5, and 91.9%, respectively. The extracts that presented antimicrobial activity were tested for hemolytic assay against human A, B, and O blood types and rabbit blood. From those, only the Myracrodruon urundeuva extract presented activity (about 20% of hemolysis at the lowest tested concentration, 1.9 µg/mL). Infrared spectroscopy of six representative extracts attested the presence of tannins, polyphenols, and flavonoids, which was confirmed by a qualitative phytochemical assay. PMID:24386637

Sorption of fluoroquinolones and sulfonamides in 13 Brazilian soils.

PubMed

Leal, Rafael Marques Pereira; Alleoni, Luis Reynaldo Ferracciú; Tornisielo, Valdemar Luiz; Regitano, Jussara Borges

2013-08-01

Animal production is a leading economic activity in Brazil and antibiotics are widely used. However, the occurrence, behavior, and impacts of antibiotics in Brazilian soils are still poorly known. We evaluated the sorption behavior of four fluoroquinolones (norfloxacin, ciprofloxacin, danofloxacin, and enrofloxacin) and five sulfonamides (sulfadiazine, sulfachloropyridazine, sulfamethoxazole, sulfadimidine, and sulfathiazole) in 13 Brazilian soils with contrasting physical, chemical, and mineralogical properties. Fluoroquinolone sorption was very high (Kd≥544 L kg(-1)) whereas sulfonamide sorption ranged from low to high (Kd=0.7-70.1 L kg(-1)), consistent with previous reports in the literature. Soil texture and cation exchange capacity were the soil attributes that most affected sorption. Cation exchange was the most important sorption mechanism for the fluoroquinolones in highly weathered tropical soils, although cation bridging and ion pairing could not be ruled out. Hydrophobic partition played an important role in the sorption of the sulfonamides, but sorption was also affected by non-hydrophobic interactions with organic and/or mineral surfaces. Sorption for both compound classes tended to be higher in soils with high Al and Fe oxihydroxide contents, but they were not correlated with Kd values. No direct effect of soil pH was seen. The fluoroquinolones are not expected to leach even in worst-case scenarios (soils rich in sand and poor in organic carbon), whereas soil attributes dictate leaching potential for the sulfonamides. Copyright © 2013 Elsevier Ltd. All rights reserved.

The underestimated biodiversity of tropical grassy biomes

PubMed Central

Andersen, Alan N.; Parr, Catherine L.

2016-01-01

For decades, there has been enormous scientific interest in tropical savannahs and grasslands, fuelled by the recognition that they are a dynamic and potentially unstable biome, requiring periodic disturbance for their maintenance. However, that scientific interest has not translated into widespread appreciation of, and concern about threats to, their biodiversity. In terms of biodiversity, grassy biomes are considered poor cousins of the other dominant biome of the tropics—forests. Simple notions of grassy biomes being species-poor cannot be supported; for some key taxa, such as vascular plants, this may be valid, but for others it is not. Here, we use an analysis of existing data to demonstrate that high-rainfall tropical grassy biomes (TGBs) have vertebrate species richness comparable with that of forests, despite having lower plant diversity. The Neotropics stand out in terms of both overall vertebrate species richness and number of range-restricted vertebrate species in TGBs. Given high rates of land-cover conversion in Neotropical grassy biomes, they should be a high priority for conservation and greater inclusion in protected areas. Fire needs to be actively maintained in these systems, and in many cases re-introduced after decades of inappropriate fire exclusion. The relative intactness of TGBs in Africa and Australia make them the least vulnerable to biodiversity loss in the immediate future. We argue that, like forests, TGBs should be recognized as a critical—but increasingly threatened—store of global biodiversity. This article is part of the themed issue ‘Tropical grassy biomes: linking ecology, human use and conservation’. PMID:27502382

Optimal use of land surface temperature data to detect changes in tropical forest cover

NASA Astrophysics Data System (ADS)

van Leeuwen, Thijs T.; Frank, Andrew J.; Jin, Yufang; Smyth, Padhraic; Goulden, Michael L.; van der Werf, Guido R.; Randerson, James T.

2011-06-01

Rapid and accurate assessment of global forest cover change is needed to focus conservation efforts and to better understand how deforestation is contributing to the buildup of atmospheric CO2. Here we examined different ways to use land surface temperature (LST) to detect changes in tropical forest cover. In our analysis we used monthly 0.05° × 0.05° Terra Moderate Resolution Imaging Spectroradiometer (MODIS) observations of LST and Program for the Estimation of Deforestation in the Brazilian Amazon (PRODES) estimates of forest cover change. We also compared MODIS LST observations with an independent estimate of forest cover loss derived from MODIS and Landsat observations. Our study domain of approximately 10° × 10° included the Brazilian state of Mato Grosso. For optimal use of LST data to detect changes in tropical forest cover in our study area, we found that using data sampled during the end of the dry season (˜1-2 months after minimum monthly precipitation) had the greatest predictive skill. During this part of the year, precipitation was low, surface humidity was at a minimum, and the difference between day and night LST was the largest. We used this information to develop a simple temporal sampling algorithm appropriate for use in pantropical deforestation classifiers. Combined with the normalized difference vegetation index, a logistic regression model using day-night LST did moderately well at predicting forest cover change. Annual changes in day-night LST decreased during 2006-2009 relative to 2001-2005 in many regions within the Amazon, providing independent confirmation of lower deforestation levels during the latter part of this decade as reported by PRODES.

Topology of Plant - Flower-Visitor Networks in a Tropical Mountain Forest: Insights on the Role of Altitudinal and Temporal Variation.

PubMed

Cuartas-Hernández, Sandra; Medel, Rodrigo

2015-01-01

Understanding the factors determining the spatial and temporal variation of ecological networks is fundamental to the knowledge of their dynamics and functioning. In this study, we evaluate the effect of elevation and time on the structure of plant-flower-visitor networks in a Colombian mountain forest. We examine the level of generalization of plant and animal species and the identity of interactions in 44 bipartite matrices obtained from eight altitudinal levels, from 2200 to 2900 m during eight consecutive months. The contribution of altitude and time to the overall variation in the number of plant (P) and pollinator (A) species, network size (M), number of interactions (I), connectance (C), and nestedness was evaluated. In general, networks were small, showed high connectance values and non-nested patterns of organization. Variation in P, M, I and C was better accounted by time than elevation, seemingly related to temporal variation in precipitation. Most plant and insect species were specialists and the identity of links showed a high turnover over months and at every 100 m elevation. The partition of the whole system into smaller network units allowed us to detect small-scale patterns of interaction that contrasted with patterns commonly described in cumulative networks. The specialized but erratic pattern of network organization observed in this tropical mountain suggests that high connectance coupled with opportunistic attachment may confer robustness to plant-flower-visitor networks occurring at small spatial and temporal units.

Overstory structure and soil nutrients effect on plant diversity in unmanaged moist tropical forest

NASA Astrophysics Data System (ADS)

Gautam, Mukesh Kumar; Manhas, Rajesh Kumar; Tripathi, Ashutosh Kumar

2016-08-01

Forests with intensive management past are kept unmanaged to restore diversity and ecosystem functioning. Before perpetuating abandonment after protracted restitution, understanding its effect on forest vegetation is desirable. We studied plant diversity and its relation with environmental variables and stand structure in northern Indian unmanaged tropical moist deciduous forest. We hypothesized that post-abandonment species richness would have increased, and the structure of contemporary forest would be heterogeneous. Vegetation structure, composition, and diversity were recorded, in forty 0.1 ha plots selected randomly in four forest ranges. Three soil samples per 0.1 ha were assessed for physicochemistry, fine sand, and clay mineralogy. Contemporary forest had less species richness than pre-abandonment reference period. Fourteen species were recorded as either seedling or sapling, suggesting reappearance or immigration. For most species, regeneration was either absent or impaired. Ordination and multiple regression results showed that exchangeable base cations and phosphorous affected maximum tree diversity and structure variables. Significant correlations between soil moisture and temperature, and shrub layer was observed, besides tree layer correspondence with shrub richness, suggesting that dense overstory resulting from abandonment through its effect on soil conditions, is responsible for dense shrub layer. Herb layer diversity was negatively associated with tree layer and shrub overgrowth (i.e. Mallotus spp.). Protracted abandonment may not reinforce species richness and heterogeneity; perhaps result in high tree and shrub density in moist deciduous forests, which can impede immigrating or reappearing plant species establishment. This can be overcome by density/basal area reduction strategies, albeit for both tree and shrub layer.

Proposal for MSW contaminant classification applied to a tropical aquifer.

PubMed

de Faria, Gabriel Messias Moura; Mondelli, Giulliana

2018-04-01

Groundwater is a natural resource exploited worldwide causing danger due to the lixiviation of waste deposited, which presents high potential degradation. Internationally, regulation aims for the maintenance of the quality of this resource. But the local lithology, mainly in countries with tropical weather, was not considered. This paper has an objective to propose two methodologies of contaminant identification of municipal solid waste (MSW) considering the Brazilian regulation, the local lithology and the temporal aspect. The study site is located in the midwest of São Paulo, at the Marília Formation, Bauru Aquifer, which presents sandstone rich in calcite. At first, the historic monitoring data accumulated between 2002 and 2015 were statistically organized. Then, methodologies of classification of major constituents and contamination method were developed. After these analyses, the compounds that possibly cause anomaly in the local environment are Al, As, Ba, Ca, Cd, Co, Cr, Cu, phosphatic, nitrogenous, and sulfated compounds, Fe, K, Mn, Ni, and Pb. Some of these have lithogenic genesis typical of tropical environment, and others come from the disposed waste. Despite different approaches, both methods demonstrate efficiency in identifying the pollutants presenting distinctions among themselves in conjunction with actual local regulation and the lithogenic source of certain compounds.

Seed-deposition and recruitment patterns of Clusia species in a disturbed tropical montane forest in Bolivia

NASA Astrophysics Data System (ADS)

Saavedra, Francisco; Hensen, Isabell; Apaza Quevedo, Amira; Neuschulz, Eike Lena; Schleuning, Matthias

2017-11-01

Spatial patterns of seed dispersal and recruitment of fleshy-fruited plants in tropical forests are supposed to be driven by the activity of animal seed dispersers, but the spatial patterns of seed dispersal, seedlings and saplings have rarely been analyzed simultaneously. We studied seed deposition and recruitment patterns of three Clusia species in a tropical montane forest of the Bolivian Andes and tested whether these patterns changed between habitat types (forest edge vs. forest interior), distance to the fruiting tree and consecutive recruitment stages of the seedlings. We recorded the number of seeds deposited in seed traps to assess the local seed-deposition pattern and the abundance and distribution of seedlings and saplings to evaluate the spatial pattern of recruitment. More seeds were removed and deposited at the forest edge than in the interior. The number of deposited seeds decreased with distance from the fruiting tree and was spatially clustered in both habitat types. The density of 1-yr-old seedlings and saplings was higher at forest edges, whereas the density of 2-yr-old seedlings was similar in both habitat types. While seedlings were almost randomly distributed, seeds and saplings were spatially clustered in both habitat types. Our findings demonstrate systematic changes in spatial patterns of recruits across the plant regeneration cycle and suggest that the differential effects of biotic and abiotic factors determine plant recruitment at the edges and in the interior of tropical montane forests. These differences in the spatial distribution of individuals across recruitment stages may have strong effects on plant community dynamics and influence plant species coexistence in disturbed tropical forests.

An ethnobotanical study of anti-malarial plants among indigenous people on the upper Negro River in the Brazilian Amazon.

PubMed

Frausin, Gina; Hidalgo, Ari de Freitas; Lima, Renata Braga Souza; Kinupp, Valdely Ferreira; Ming, Lin Chau; Pohlit, Adrian Martin; Milliken, William

2015-11-04

In this article we present the plants used for the treatment of malaria and associated symptoms in Santa Isabel do Rio Negro in the Brazilian Amazon. The region has important biological and cultural diversities including more than twenty indigenous ethnic groups and a strong history in traditional medicine. The aims of this study are to survey information in the Baniwa, Baré, Desana, Piratapuia, Tariana, Tukano, Tuyuca and Yanomami ethnic communities and among caboclos (mixed-ethnicity) on (a) plant species used for the treatment of malaria and associated symptoms, (b) dosage forms and (c) distribution of these anti-malarial plants in the Amazon. Information was obtained through classical ethnobotanical and ethnopharmacological methods from interviews with 146 informants in Santa Isabel municipality on the upper Negro River, Brazil. Fifty-five mainly native neotropical plant species from 34 families were in use. The detailed uses of these plants were documented. The result was 187 records (64.5%) of plants for the specific treatment of malaria, 51 records (17.6%) of plants used in the treatment of liver problems and 29 records (10.0%) of plants used in the control of fevers associated with malaria. Other uses described were blood fortification ('dar sangue'), headache and prophylaxis. Most of the therapeutic preparations were decoctions and infusions based on stem bark, root bark and leaves. These were administered by mouth. In some cases, remedies were prepared with up to three different plant species. Also, plants were used together with other ingredients such as insects, mammals, gunpowder and milk. This is the first study on the anti-malarial plants from this region of the Amazon. Aspidosperma spp. and Ampelozizyphus amazonicus Ducke were the most cited species in the communities surveyed. These species have experimental proof supporting their anti-malarial efficacy. The dosage of the therapeutic preparations depends on the kind of plant, quantity of plant

Patterns in understory woody diversity and soil nitrogen across native- and non-native-urban tropical forests

Treesearch

D.F. Cusack; T.L. McCleery; NO-VALUE

2014-01-01

Urban expansion is accelerating in the tropics, and may promote the spread of introduced plant species into urban-proximate forests. For example, soil disturbance can deplete the naturally high soil nitrogen pools in wet tropical soils, favoring introduced species with nitrogen-fixing capabilities. Also, forest fragmentation and canopy disturbance are likely to favor...

Flood Frequency Analysis Under Non-stationarity Conditions: the Case of Southern Brazilian Hydroelectric Power Plants

NASA Astrophysics Data System (ADS)

Bartiko, Daniel; Chaffe, Pedro; Bonumá, Nadia

2017-04-01

Floods may be strongly affected by climate, land-use, land-cover and water infrastructure changes. However, it is common to model this process as stationary. This approach has been questioned, especially when it involves estimate of the frequency and magnitude of extreme events for designing and maintaining hydraulic structures, as those responsible for flood control and dams safety. Brazil is the third largest producer of hydroelectricity in the world and many of the country's dams are located in the Southern Region. So, it seems appropriate to investigate the presence of non-stationarity in the affluence in these plants. In our study, we used historical flood data from the Brazilian National Grid Operator (ONS) to explore trends in annual maxima in river flow of the 38 main rivers flowing to Southern Brazilian reservoirs (records range from 43 to 84 years). In the analysis, we assumed a two-parameter log-normal distribution a linear regression model was applied in order to allow for the mean to vary with time. We computed recurrence reduction factors to characterize changes in the return period of an initially estimated 100 year-flood by a log-normal stationary model. To evaluate whether or not a particular site exhibits positive trend, we only considered data series with linear regression slope coefficients that exhibit significance levels (p<0,05). The significance level was calculated using the one-sided Student's test. The trend model residuals were analyzed using the Anderson-Darling normality test, the Durbin-Watson test for the independence and the Breusch-Pagan test for heteroscedasticity. Our results showed that 22 of the 38 data series analyzed have a significant positive trend. The trends were mainly in three large basins: Iguazu, Uruguay and Paranapanema, which suffered changes in land use and flow regularization in the last years. The calculated return period for the series that presented positive trend varied from 50 to 77 years for a 100 year

Assessing diversity and phytoremediation potential of seagrass in tropical region

USDA-ARS?s Scientific Manuscript database

Seagrass ecosystem is one of the most important resources in the coastal areas. Seagrasses support and provide habitats for many coastal organisms in tropical region. Seagrasses are specialized marine flowering plants that have adapted to the nearshore environment with heterogeneous landscape struct...

Airborne observations reveal elevational gradient in tropical forest isoprene emissions

DOE PAGES

Gu, Dasa; Guenther, Alex B.; Shilling, John E.; ...

2017-05-23

Terrestrial vegetation emits vast quantities of volatile organic compounds (VOCs) to he atmosphere1-3, which influence oxidants and aerosols leading to complex feedbacks on air quality and climate4-6. Isoprene dominates global non-methane VOC emissions with tropical regions contributing ~80% of global isoprene emissions2. Isoprene emission rates vary over several orders of magnitude for different plant species, and characterizing this immense biological chemodiversity is a challenge for estimating isoprene emission from tropical forests. Here we present the isoprene emission estimates from aircraft direct eddy covariance measurements over the pristine Amazon forest. We report isoprene emission rates that are 3 times higher thanmore » satellite top-down estimates and 35% higher than model predictions based on satellite land cover and vegetation specific emission factors (EFs). The results reveal strong correlations between observed isoprene emission rates and terrain elevations which are confirmed by similar correlations between satellite-derived isoprene emissions and terrain elevations. We propose that the elevational gradient in the Amazonian forest isoprene emission capacity is determined by plant species distributions and can explain a substantial degree of isoprene emission variability in tropical forests. Finally, we apply this approach over the central Amazon and use a model to demonstrate the impacts on regional air quality.« less

Near-continuous thermal monitoring of a diverse tropical forest canopy

NASA Astrophysics Data System (ADS)

Pau, S.; Still, C. J.; Kim, Y.; Detto, M.

2015-12-01

Tropical species may be highly sensitive to temperature increases associated with climate change because of their narrow thermal tolerances. Recent work has highlighted the importance of temperature in tropical forest function, however most studies use air temperature measurements from sparse meteorological stations even though surface temperatures are known to deviate from air temperatures. Tropical organisms exist in microclimates that are highly variable in space and time and not easily measured in natural environments. This is in part because of the complex structure of tropical forests and the potential for organisms themselves to modify their own environment. In the case of plants, leaf temperature is linked to the water and surface energy balance of their microenvironment. Here we present results from near-continuous thermal camera monitoring of the forest canopy in Barro Colorado Island, Panama (5-minute intervals for approximately 9 months). We compare daytime (maximum) vs. nighttime (minimum) differences between canopy temperature and air temperature, relative humidity, solar radiation, and precipitation. On average, canopy temperatures are consistently ~2 degrees Celsius higher than air temperatures. These data can paired with flux tower data on-site and used to advance understanding of temperature controls on the structure and function of tropical forests, such as carbon assimilation, phenology, and habitat monitoring, and can be integrated into models to improve predictions of tropical forest response to future climate change.

Pharmacogenetics in the Brazilian Population

PubMed Central

Suarez-Kurtz, Guilherme

2010-01-01

Brazil is the fifth largest country in the world and its present population, in excess of 190;million, is highly heterogeneous, as a result of centuries of admixture between Amerindians, Europeans, and Sub-Saharan Africans. The estimated individual proportions of biogeographical ancestry vary widely and continuously among Brazilians: most individuals, irrespective of self-identification as White, Brown or Black – the major categories of the Brazilian Census “race/color” system – have significant degrees of European and African ancestry, while a sizeable number display also Amerindian ancestry. These features have important pharmacogenetic (PGx) implications: first, extrapolation of PGx data from relatively well-defined ethnic groups is clearly not applicable to the majority of Brazilians; second, the frequency distribution of polymorphisms in pharmacogenes (e.g., CYP3A5, CYP2C9, GSTM1, ABCB1, GSTM3, VKORC, etc) varies continuously among Brazilians and is not captured by race/color self-identification; third, the intrinsic heterogeneity of the Brazilian population must be acknowledged in the design and interpretation of PGx studies in order to avoid spurious conclusions based on improper matching of study cohorts. The peculiarities of PGx in Brazilians are illustrated with data for different therapeutic groups, such as anticoagulants, HIV protease inhibitors and non-steroidal antinflammatory drugs, and the challenges and advantages created by population admixture for the study and implementation of PGx are discussed. PGx data for Amerindian groups and Brazilian-born, first-generation Japanese are presented to illustrate the rich diversity of the Brazilian population. Finally, I introduce the reader to the Brazilian Pharmacogenetic Network or Refargen1, a nation-wide consortium of research groups, with the mission to provide leadership in PGx research and education in Brazil, with a population health impact. PMID:21833165

Hot and Bothered: Changes in Microclimate Alter Chlorophyll Fluorescence Measures and Increase Stress Levels in Tropical Epiphytic Orchids

Treesearch

Benjamin J. Crain; Raymond L. Tremblay

2017-01-01

Premise of research. Tropical epiphytes are susceptible to climatic changes, as evidenced by documented population declines, range contractions, and range shifts; however, physiological changes in individual plants may also be indicative of deteriorating climate conditions. Consequently, physiological analyses of tropical epiphytes whose natural habitats are...

Estimating Mesophyll Conductance in the Tropical Rainforest

NASA Astrophysics Data System (ADS)

Coughlin, I.

2015-12-01

In the current research modeling the carbon cycle, some of the biggest setbacks are methodological barriers to calculating the gross primary production (GPP) in the terrestrial biosphere. However, recent developments in high precision gas measurements now allow the use of COS as a potential tracer for determination of GPP, independently of CO2 .Since the tropics are implicated as being the source of the most significant reduction of carbon uptake by the majority of models, making accurate GPP measurements in the tropics is particularly important for carbon modeling. In order to constrain measurements of GPP in the tropics, carbonyl sulfide fluxes on a leaf chamber scale and a canopy-wide scale will be analyzed in a field site in the central Amazon. Accompanying this experiment, I am measuring the resistance of CO2 passing through the intercellular airspaces in the leaf to the sites of carboxylation, known as mesophyll conductance. Mesophyll conductance is poorly documented in the tropics, and remains a centrally limiting factor in plant uptake of COS and CO2 - with upward estimates of 40% of the CO2 diffusional limitation of photosynthesis hinging on mesophyll conductance (Warren, 2008). This makes mesophyll conductance comparable in magnitude to that of the stomatal conductance, suggesting that mesophyll conductance is one of the most fundamental measurements necessary for developing the predictive capacity of plants' response to ecosystem changes. Accurate measurements of the mesophyll conductance also lead to better informed models that can upscale assimilation measurements from leaf chambers, by providing quantitative constraints for modeling the uptake of carbonyl sulfide and carbon dioxide by the leaf. Additionally, since mesophyll conductance reacts to environmental variation, it can be used as an indicator for leaf stress. Measurements are taken using the 'variable J' technique, involving the use of combined fluorescence measurements and gas exchange data

The preconditioning role of Tropical Atlantic Variability in the development of the ENSO teleconnection: implications for the prediction of Nordeste rainfall

NASA Astrophysics Data System (ADS)

Giannini, A.; Saravanan, R.; Chang, P.

A comparison of rainfall variability in the semi-arid Brazilian Nordeste in observations and in two sets of model simulations leads to the conclusion that the evolving interaction between Tropical Atlantic Variability (TAV) and the El Niño-Southern Oscillation (ENSO) phenomenon can explain two puzzling features of ENSO's impact on the Nordeste: (1) the event-to-event unpredictability of ENSO's impact; (2) the greater impact of cold rather than warm ENSO events during the past 50 years. The explanation is in the `preconditioning' role of Tropical Atlantic Variability. When, in seasons prior to the mature phase of ENSO, the tropical Atlantic happens to be evolving consistently with the development expected of the ENSO teleconnection, ENSO and TAV add up to force large anomalies in Nordeste rainfall. When it happens to be evolving in opposition to the canonical development of ENSO, then the net outcome is less obvious, but also less anomalous. The more frequent occurrence of tropical Atlantic conditions consistent with those that develop during a cold ENSO event, i.e. of a negative meridional sea surface temperature gradient, explains the weaker warm ENSO and stronger cold ENSO anomalies in Nordeste rainfall of the latter part of the twentieth century. Close monitoring of the evolution of the tropical Atlantic in seasons prior to the mature phase of ENSO should lead to an enhanced forecast potential.

Afforestation by natural regeneration or by tree planting: examples of opposite hydrological impacts evidenced by long-term field monitoring in the humid tropics

NASA Astrophysics Data System (ADS)

Lacombe, G.; Ribolzi, O.; de Rouw, A.; Pierret, A.; Latsachak, K.; Silvera, N.; Pham Dinh, R.; Orange, D.; Janeau, J.-L.; Soulileuth, B.; Robain, H.; Taccoen, A.; Sengphaathith, P.; Mouche, E.; Sengtaheuanghoung, O.; Tran Duc, T.; Valentin, C.

2015-12-01

The humid tropics are exposed to an unprecedented modernization of agriculture involving rapid and highly-mixed land-use changes with contrasted environmental impacts. Afforestation is often mentioned as an unambiguous solution for restoring ecosystem services and enhancing biodiversity. One consequence of afforestation is the alteration of streamflow variability controlling habitats, water resources and flood risks. We demonstrate that afforestation by tree planting or by natural forest regeneration can induce opposite hydrological changes. An observatory including long-term field measurements of fine-scale land-use mosaics and of hydro-meteorological variables has been operating in several headwater catchments in tropical Southeast Asia since 2001. The GR2M water balance model repeatedly calibrated over successive 1 year periods, and used in simulation mode with specific rainfall input, allowed the hydrological effect of land-use change to be isolated from that of rainfall variability in two of these catchments in Laos and Vietnam. Visual inspection of hydrographs, correlation analyses and trend detection tests allowed causality between land-use changes and changes in seasonal flows to be ascertained. In Laos, the combination of shifting cultivation system (alternation of rice and fallow) and the gradual increase of teak tree plantations replacing fallow, led to intricate flow patterns: pluri-annual flow cycles induced by the shifting system, on top of a gradual flow increase over years caused by the spread of the plantation. In Vietnam, the abandonment of continuously cropped areas mixed with patches of tree plantations led to the natural re-growth of forest communities followed by a gradual drop in streamflow. Soil infiltrability controlled by surface crusting is the predominant process explaining why two modes of afforestation (natural regeneration or planting) led to opposite changes in flow regime. Given that commercial tree plantations will continue to

Land crabs as key drivers in tropical coastal forest recruitment

USGS Publications Warehouse

Lindquist, E.S.; Krauss, K.W.; Green, P.T.; O'Dowd, D. J.; Sherman, P.M.; Smith, T. J.

2009-01-01

Plant populations are regulated by a diverse assortment of abiotic and biotic factors that influence seed dispersal and viability, and seedling establishment and growth at the microsite. Rarely does one animal guild exert as significant an influence on different plant assemblages as land crabs. We review three tropical coastal ecosystems-mangroves, island maritime forests, and mainland coastal terrestrial forests-where land crabs directly influence forest composition by limiting tree establishment and recruitment. Land crabs differentially prey on seeds, propagules and seedlings along nutrient, chemical and physical environmental gradients. In all of these ecosystems, but especially mangroves, abiotic gradients are well studied, strong and influence plant species distributions. However, we suggest that crab predation has primacy over many of these environmental factors by acting as the first limiting factor of tropical tree recruitment to drive the potential structural and compositional organisation of coastal forests. We show that the influence of crabs varies relative to tidal gradient, shoreline distance, canopy position, time, season, tree species and fruiting periodicity. Crabs also facilitate forest growth and development through such activities as excavation of burrows, creation of soil mounds, aeration of soils, removal of leaf litter into burrows and creation of carbon-rich soil microhabitats. For all three systems, land crabs influence the distribution, density and size-class structure of tree populations. Indeed, crabs are among the major drivers of tree recruitment in tropical coastal forest ecosystems, and their conservation should be included in management plans of these forests. ?? 2009 Cambridge Philosophical Society.

Resource partitioning by evergreen and deciduous species in a tropical dry forest.

PubMed

Álvarez-Yépiz, Juan C; Búrquez, Alberto; Martínez-Yrízar, Angelina; Teece, Mark; Yépez, Enrico A; Dovciak, Martin

2017-02-01

Niche differentiation can lead to coexistence of plant species by partitioning limiting resources. Light partitioning promotes niche differentiation in tropical humid forests, but it is unclear how niche partitioning occurs in tropical dry forests where both light and soil resources can be limiting. We studied the adult niche of four dominant evergreen (cycad, palm) and drought-deciduous (legume, oak) species co-occurring along environmental gradients. We analyzed light intensity and soil fertility effects on key functional traits related to plant carbon and water economy, how these traits determine species' functional strategies, and how these strategies relate to relative species abundance and spatial patterns. Light intensity was negatively associated with a key trait linked to plant water economy (leaf δ 13 C, a proxy for long-term water-use efficiency-WUE), while soil fertility was negatively associated with a key trait for plant carbon economy (LNC, leaf nitrogen content). Evergreens were highly sclerophyllous and displayed an efficient water economy but poor carbon economy, in agreement with a conservative resource-use strategy (i.e., high WUE but low LNC, photosynthetic rates and stature). Conversely, deciduous species, with an efficient carbon economy but poor water economy, exhibited an exploitative resource-use strategy (i.e., high LNC, photosynthetic rates and stature, but low WUE). Evergreen and deciduous species segregated spatially, particularly at fine-scales, as expected for species with different resource-use strategies. The efficient water economy of evergreens was related to their higher relative abundance, suggesting a functional advantage against drought-deciduous species in water-limited environments within seasonally dry tropical forests.

Biosynthetic Potential of Phylogenetically Unique Endophytic Actinomycetes from Tropical Plants▿ †

PubMed Central

Janso, Jeffrey E.; Carter, Guy T.

2010-01-01

The culturable diversity of endophytic actinomycetes associated with tropical, native plants is essentially unexplored. In this study, 123 endophytic actinomycetes were isolated from tropical plants collected from several locations in Papua New Guinea and Mborokua Island, Solomon Islands. Isolates were found to be prevalent in roots but uncommon in leaves. Initially, isolates were dereplicated to the strain level by ribotyping. Subsequent characterization of 105 unique strains by 16S rRNA gene sequence analysis revealed that 17 different genera were represented, and rare genera, such as Sphaerisporangium and Planotetraspora, which have never been previously reported to be endophytic, were quite prevalent. Phylogenetic analyses grouped many of the strains into clades distinct from known genera within Thermomonosporaceae and Micromonosporaceae, indicating that they may be unique genera. Bioactivity testing and liquid chromatography-mass spectrometry (LC-MS) profiling of crude fermentation extracts were performed on 91 strains. About 60% of the extracts exhibited bioactivity or displayed LC-MS profiles with spectra indicative of secondary metabolites. The biosynthetic potential of 29 nonproductive strains was further investigated by the detection of putative polyketide synthase (PKS) and nonribosomal peptide synthetase (NRPS) genes. Despite their lack of detectable secondary metabolite production in fermentation, most were positive for type I (66%) and type II (79%) PKS genes, and all were positive for NRPS genes. These results suggest that tropical plants from New Guinea and the adjacent archipelago are hosts to unique endophytic actinomycetes that possess significant biosynthetic potential. PMID:20472734

Potentially Extreme Population Displacement and Concentration in the Tropics Under Non-Extreme Warming

NASA Astrophysics Data System (ADS)

Hsiang, Solomon M.; Sobel, Adam H.

2016-06-01

Evidence increasingly suggests that as climate warms, some plant, animal, and human populations may move to preserve their environmental temperature. The distances they must travel to do this depends on how much cooler nearby surfaces temperatures are. Because large-scale atmospheric dynamics constrain surface temperatures to be nearly uniform near the equator, these displacements can grow to extreme distances in the tropics, even under relatively mild warming scenarios. Here we show that in order to preserve their annual mean temperatures, tropical populations would have to travel distances greater than 1000 km over less than a century if global mean temperature rises by 2 °C over the same period. The disproportionately rapid evacuation of the tropics under such a scenario would cause migrants to concentrate in tropical margins and the subtropics, where population densities would increase 300% or more. These results may have critical consequences for ecosystem and human wellbeing in tropical contexts where alternatives to geographic displacement are limited.

Scatter Hoarding of Seeds Confers Survival Advantages and Disadvantages to Large-Seeded Tropical Plants at Different Life Stages

PubMed Central

Kuprewicz, Erin K.

2015-01-01

Scatter hoarding of seeds by animals contributes significantly to forest-level processes, including plant recruitment and forest community composition. However, the potential positive and negative effects of caching on seed survival, germination success, and seedling survival have rarely been assessed through experimental studies. Here, I tested the hypothesis that seed burial mimicking caches made by scatter hoarding Central American agoutis (Dasyprocta punctate) enhances seed survival, germination, and growth by protecting seeds from seed predators and providing favorable microhabitats for germination. In a series of experiments, I used simulated agouti seed caches to assess how hoarding affects seed predation by ground-dwelling invertebrates and vertebrates for four plant species. I tracked germination and seedling growth of intact and beetle-infested seeds and, using exclosures, monitored the effects of mammals on seedling survival through time. All experiments were conducted over three years in a lowland wet forest in Costa Rica. The majority of hoarded palm seeds escaped predation by both invertebrates and vertebrates while exposed seeds suffered high levels of infestation and removal. Hoarding had no effect on infestation rates of D. panamensis, but burial negatively affected germination success by preventing endocarp dehiscence. Non-infested palm seeds had higher germination success and produced larger seedlings than infested seeds. Seedlings of A. alatum and I. deltoidea suffered high mortality by seed-eating mammals. Hoarding protected most seeds from predators and enhanced germination success (except for D. panamensis) and seedling growth, although mammals killed many seedlings of two plant species; all seedling deaths were due to seed removal from the plant base. Using experimental caches, this study shows that scatter hoarding is beneficial to most seeds and may positively affect plant propagation in tropical forests, although tradeoffs in seed

Life Expectancy of Brazilian Neurosurgeons.

PubMed

Botelho, Ricardo Vieira; Jardim Miranda, Bárbara Cristina; Nishikuni, Koshiro; Waisberg, Jaques

2018-06-01

Life expectancy (LE) refers to the number of years that an individual is expected to survive. Emphasis is frequently placed on the relationship between LE and the conditions under which a population lives, but fewer studies have investigated the relationship between stress factors associated with specific professions and their effects on LE. The aim of this study is to evaluate Brazilian neurosurgeons' life expectancies (BNLEs) and compare them with those of physicians (both Brazilian and foreign) from other fields, as well as with Brazilian nondoctors. The Brazilian Society of Neurosurgery death registry was used to obtain data that compared LEs from non-neurosurgeon physicians, as described in the national and international literature. BNLEs were also compared with the LEs of Brazilian citizens. Fifty-one neurosurgeons died between 2009 and 2016. All were males. The mean age at death was 68.31 ± 17.71 years. Among all-cause mortality, the breakdown was 20% cardiovascular diseases, 39% malignancies, 10% external factors, 6% gastrointestinal disorders, 12% neurologic illnesses, and 14% unknown causes. BNLE was shorter than LE of male Brazilian citizens. LE was similar among neurosurgeons and other doctors but shorter compared with Brazilian citizens. Further research is needed to provide data that can add to and confirm these results. Copyright © 2018 Elsevier Inc. All rights reserved.

Sustaining the productivity of planted forests

Treesearch

R.F. Powers; A.E. Tiarks; J.A. Burger; M.C. Carter

1996-01-01

Conversion of natural forests to plantations, particularly in the tropics, has drawn global attention and concern. Moreover, plantation forestry is on the rise, especially in tropical and subtropical regions where growth rates are rapid. Even in the United States, where even-age silviculture is being deemphasized on public land (only about 15 percent of all plantings...

Two mycoheterotrophic orchids from Thailand tropical dipterocarpacean forests associate with a broad diversity of ectomycorrhizal fungi

PubMed Central

Roy, Mélanie; Watthana, Santi; Stier, Anna; Richard, Franck; Vessabutr, Suyanee; Selosse, Marc-André

2009-01-01

Background Mycoheterotrophic plants are considered to associate very specifically with fungi. Mycoheterotrophic orchids are mostly associated with ectomycorrhizal fungi in temperate regions, or with saprobes or parasites in tropical regions. Although most mycoheterotrophic orchids occur in the tropics, few studies have been devoted to them, and the main conclusions about their specificity have hitherto been drawn from their association with ectomycorrhizal fungi in temperate regions. Results We investigated three Asiatic Neottieae species from ectomycorrhizal forests in Thailand. We found that all were associated with ectomycorrhizal fungi, such as Thelephoraceae, Russulaceae and Sebacinales. Based on 13C enrichment of their biomass, they probably received their organic carbon from these fungi, as do mycoheterotrophic Neottieae from temperate regions. Moreover, 13C enrichment suggested that some nearby green orchids received part of their carbon from fungi too. Nevertheless, two of the three orchids presented a unique feature for mycoheterotrophic plants: they were not specifically associated with a narrow clade of fungi. Some orchid individuals were even associated with up to nine different fungi. Conclusion Our results demonstrate that some green and mycoheterotrophic orchids in tropical regions can receive carbon from ectomycorrhizal fungi, and thus from trees. Our results reveal the absence of specificity in two mycoheterotrophic orchid-fungus associations in tropical regions, in contrast to most previous studies of mycoheterotrophic plants, which have been mainly focused on temperate orchids. PMID:19682351

Two mycoheterotrophic orchids from Thailand tropical dipterocarpacean forests associate with a broad diversity of ectomycorrhizal fungi.

PubMed

Roy, Mélanie; Watthana, Santi; Stier, Anna; Richard, Franck; Vessabutr, Suyanee; Selosse, Marc-André

2009-08-14

Mycoheterotrophic plants are considered to associate very specifically with fungi. Mycoheterotrophic orchids are mostly associated with ectomycorrhizal fungi in temperate regions, or with saprobes or parasites in tropical regions. Although most mycoheterotrophic orchids occur in the tropics, few studies have been devoted to them, and the main conclusions about their specificity have hitherto been drawn from their association with ectomycorrhizal fungi in temperate regions. We investigated three Asiatic Neottieae species from ectomycorrhizal forests in Thailand. We found that all were associated with ectomycorrhizal fungi, such as Thelephoraceae, Russulaceae and Sebacinales. Based on 13C enrichment of their biomass, they probably received their organic carbon from these fungi, as do mycoheterotrophic Neottieae from temperate regions. Moreover, 13C enrichment suggested that some nearby green orchids received part of their carbon from fungi too. Nevertheless, two of the three orchids presented a unique feature for mycoheterotrophic plants: they were not specifically associated with a narrow clade of fungi. Some orchid individuals were even associated with up to nine different fungi. Our results demonstrate that some green and mycoheterotrophic orchids in tropical regions can receive carbon from ectomycorrhizal fungi, and thus from trees. Our results reveal the absence of specificity in two mycoheterotrophic orchid-fungus associations in tropical regions, in contrast to most previous studies of mycoheterotrophic plants, which have been mainly focused on temperate orchids.

Analyzing the edge effects in a Brazilian seasonally dry tropical forest.

PubMed

Arruda, D M; Eisenlohr, P V

2016-02-01

Due to the deciduous nature of dry forests (widely known as seasonally dry tropical forests) they are subject to microclimatic conditions not experienced in other forest formations. Close examinations of the theory of edge effects in dry forests are still rare and a number of questions arise in terms of this topic. In light of this situation we examined a fragment of the dry forest to respond to the following questions: (I) Are there differences in canopy cover along the edge-interior gradient during the dry season? (II) How does the microclimate (air temperature, soil temperature, and relative humidity) vary along that gradient? (III) How does the microclimate influence tree species richness, evenness and abundance along that gradient? (IV) Are certain tree species more dominant closer to the forest edges? Regressions were performed to address these questions. Their coefficients did not significantly vary from zero. Apparently, the uniform openness of the forest canopy caused a homogeneous internal microclimate, without significant differentiation in habitats that would allow modifications in biotic variables tested. We conclude that the processes of edge effect commonly seen in humid forests, not was shared with the dry forest assessed.

Effect of the environment on the secondary metabolic profile of Tithonia diversifolia: a model for environmental metabolomics of plants

NASA Astrophysics Data System (ADS)

Sampaio, Bruno Leite; Edrada-Ebel, Ruangelie; da Costa, Fernando Batista

2016-07-01

Tithonia diversifolia is an invasive weed commonly found in tropical ecosystems. In this work, we investigate the influence of different abiotic environmental factors on the plant’s metabolite profile by multivariate statistical analyses of spectral data deduced by UHPLC-DAD-ESI-HRMS and NMR methods. Different plant part samples of T. diversifolia which included leaves, stems, roots, and inflorescences were collected from two Brazilian states throughout a 24-month period, along with the corresponding monthly environmental data. A metabolomic approach employing concatenated LC-MS and NMR data was utilised for the first time to study the relationships between environment and plant metabolism. A seasonal pattern was observed for the occurrence of metabolites that included sugars, sesquiterpenes lactones and phenolics in the leaf and stem parts, which can be correlated to the amount of rainfall and changes in temperature. The distribution of the metabolites in the inflorescence and root parts were mainly affected by variation of some soil nutrients such as Ca, Mg, P, K and Cu. We highlight the environment-metabolism relationship for T. diversifolia and the combined analytical approach to obtain reliable data that contributed to a holistic understanding of the influence of abiotic environmental factors on the production of metabolites in various plant parts.

Effect of the environment on the secondary metabolic profile of Tithonia diversifolia: a model for environmental metabolomics of plants

PubMed Central

Sampaio, Bruno Leite; Edrada-Ebel, RuAngelie; Da Costa, Fernando Batista

2016-01-01

Tithonia diversifolia is an invasive weed commonly found in tropical ecosystems. In this work, we investigate the influence of different abiotic environmental factors on the plant’s metabolite profile by multivariate statistical analyses of spectral data deduced by UHPLC-DAD-ESI-HRMS and NMR methods. Different plant part samples of T. diversifolia which included leaves, stems, roots, and inflorescences were collected from two Brazilian states throughout a 24-month period, along with the corresponding monthly environmental data. A metabolomic approach employing concatenated LC-MS and NMR data was utilised for the first time to study the relationships between environment and plant metabolism. A seasonal pattern was observed for the occurrence of metabolites that included sugars, sesquiterpenes lactones and phenolics in the leaf and stem parts, which can be correlated to the amount of rainfall and changes in temperature. The distribution of the metabolites in the inflorescence and root parts were mainly affected by variation of some soil nutrients such as Ca, Mg, P, K and Cu. We highlight the environment-metabolism relationship for T. diversifolia and the combined analytical approach to obtain reliable data that contributed to a holistic understanding of the influence of abiotic environmental factors on the production of metabolites in various plant parts. PMID:27383265

The herb community of a tropical forest in central Panamá: dynamics and impact of mammalian herbivores.

PubMed

Royo, Alejandro A; Carson, Walter P

2005-08-01

Mammals are hypothesized to either promote plant diversity by preventing competitive exclusion or limit diversity by reducing the abundance of sensitive plant species through their activities as browsers or disturbance agents. Previous studies of herbivore impacts in plant communities have focused on tree species and ignored the herbaceous community. In an experiment in mature-phase, tropical moist forest sites in central Panamá, we studied the impact of excluding ground-dwelling mammals on the richness and abundance of herbs in 16, 30x45-m plots. Within each plot, we censused the herbaceous community in 28, 2x2-m subplots (1,792 m2 total area sampled). We identified over 54 species of herbs averaging 1.21 ramets m-2 and covering approximately 4.25% of the forest floor. Excluding mammals for 5 years had no impact on overall species richness. Within exclosures, however, there was a significant two-fold increase in the density of rare species. Overall herbaceous density and percent cover did not differ between exclosures and adjacent control plots, although cover did increase over time. Mammalian exclusion significantly increased the total cover of three-dominant herb species, Pharus latifolius, Calathea inocephala, and Adiantum lucidum, but did not affect their density. This study represents one of the most extensive herbaceous community censuses conducted in tropical forests and is among a few that quantify herbaceous distribution and abundance in terms of both density and cover. Additionally, this work represents the first community level test of mammalian impacts on the herbaceous community in a tropical forest to date. Our results suggest that ground dwelling mammals do not play a key role in altering the relative abundance patterns of tropical herbs in the short term. Furthermore, our results contrast sharply with prior studies on similar temporal and spatial scales that demonstrate mammals strongly alter tree seedling composition and reduce seedling density

Is the fluoride intake by diet and toothpaste in children living in tropical semi-arid city safe?

PubMed

Oliveira, Priscila Ferreira Torres de; Cury, Jaime Aparecido; Lima, Carolina Veloso; Vale, Glauber Campos; Lima, Marina de Deus Moura de; Moura, Lúcia de Fátima Almeida de Deus; Moura, Marcoeli Silva de

2018-01-01

Data about total fluoride intake in children living in a tropical semi-arid climate city is scarce, thus we conducted this study. Fifty-eight children aged two to five years, living in a Brazilian tropical city with optimally fluoridated water were selected. Dietary samples were collected using the duplicate diet method on two non-consecutive days in the children's home toothpaste was determined by subtracting the amount of fluoride recovered after brushing from the amount placed on the toothbrush. The mean total dose (SD) of fluoride intake was 0.043(0.016) mg F·kg-1·d-1, with the major (60.6%) contribution from water. The factors associated with the ingestion of fluoride from toothpaste were fluoride concentration of the toothpaste (p = 0.03) and the use of kids toothpaste (p = 0.02). The findings suggest that children have a low fluoride intake, measured by at-home meals and use of fluoride toothpaste; drinking water is the main source of fluoride ingestion.

Automated classification of tropical shrub species: a hybrid of leaf shape and machine learning approach

PubMed Central

Murat, Miraemiliana; Abu, Arpah; Yap, Hwa Jen; Yong, Kien-Thai

2017-01-01

Plants play a crucial role in foodstuff, medicine, industry, and environmental protection. The skill of recognising plants is very important in some applications, including conservation of endangered species and rehabilitation of lands after mining activities. However, it is a difficult task to identify plant species because it requires specialized knowledge. Developing an automated classification system for plant species is necessary and valuable since it can help specialists as well as the public in identifying plant species easily. Shape descriptors were applied on the myDAUN dataset that contains 45 tropical shrub species collected from the University of Malaya (UM), Malaysia. Based on literature review, this is the first study in the development of tropical shrub species image dataset and classification using a hybrid of leaf shape and machine learning approach. Four types of shape descriptors were used in this study namely morphological shape descriptors (MSD), Histogram of Oriented Gradients (HOG), Hu invariant moments (Hu) and Zernike moments (ZM). Single descriptor, as well as the combination of hybrid descriptors were tested and compared. The tropical shrub species are classified using six different classifiers, which are artificial neural network (ANN), random forest (RF), support vector machine (SVM), k-nearest neighbour (k-NN), linear discriminant analysis (LDA) and directed acyclic graph multiclass least squares twin support vector machine (DAG MLSTSVM). In addition, three types of feature selection methods were tested in the myDAUN dataset, Relief, Correlation-based feature selection (CFS) and Pearson’s coefficient correlation (PCC). The well-known Flavia dataset and Swedish Leaf dataset were used as the validation dataset on the proposed methods. The results showed that the hybrid of all descriptors of ANN outperformed the other classifiers with an average classification accuracy of 98.23% for the myDAUN dataset, 95.25% for the Flavia dataset and

Automated classification of tropical shrub species: a hybrid of leaf shape and machine learning approach.

PubMed

Murat, Miraemiliana; Chang, Siow-Wee; Abu, Arpah; Yap, Hwa Jen; Yong, Kien-Thai

2017-01-01

Plants play a crucial role in foodstuff, medicine, industry, and environmental protection. The skill of recognising plants is very important in some applications, including conservation of endangered species and rehabilitation of lands after mining activities. However, it is a difficult task to identify plant species because it requires specialized knowledge. Developing an automated classification system for plant species is necessary and valuable since it can help specialists as well as the public in identifying plant species easily. Shape descriptors were applied on the myDAUN dataset that contains 45 tropical shrub species collected from the University of Malaya (UM), Malaysia. Based on literature review, this is the first study in the development of tropical shrub species image dataset and classification using a hybrid of leaf shape and machine learning approach. Four types of shape descriptors were used in this study namely morphological shape descriptors (MSD), Histogram of Oriented Gradients (HOG), Hu invariant moments (Hu) and Zernike moments (ZM). Single descriptor, as well as the combination of hybrid descriptors were tested and compared. The tropical shrub species are classified using six different classifiers, which are artificial neural network (ANN), random forest (RF), support vector machine (SVM), k-nearest neighbour (k-NN), linear discriminant analysis (LDA) and directed acyclic graph multiclass least squares twin support vector machine (DAG MLSTSVM). In addition, three types of feature selection methods were tested in the myDAUN dataset, Relief, Correlation-based feature selection (CFS) and Pearson's coefficient correlation (PCC). The well-known Flavia dataset and Swedish Leaf dataset were used as the validation dataset on the proposed methods. The results showed that the hybrid of all descriptors of ANN outperformed the other classifiers with an average classification accuracy of 98.23% for the myDAUN dataset, 95.25% for the Flavia dataset and 99

Plant functional types are more efficient than climate in predicting spectrums of trait variation in evergreen angiosperm trees of tropical Australia and China

NASA Astrophysics Data System (ADS)

Togashi, H. F.; Prentice, I. C. C.; Atkin, O. K.; Bloomfield, K. J.; Bradford, M.; Weerasinghe, L. K.; Harrison, S. P.; Evans, B. J.; Liddell, M. J.; Wang, H.; Cao, K. F.; Fan, Z.

2015-12-01

The representation of Plant Functional Types (PFTs) in current generation of Dynamic Global Vegetation Models (DGVMs) is excessively simplistically. Key ecophysiological properties, such as photosynthesis biochemistry, are most times merely averaged and trade-off with other plant traits is often neglected. Validation of a PFT framework based in photosynthetic process is crucial to improve reliability of DGVMs. We present 431 leaf-biochemical and wood level measurements in evergreen angiosperm trees of tropical forests in Australia and China that were divided in four spectrums of plant trait variation: metabolic, structural, hydraulic and height dimensions. Plant traits divided in each of these dimensions adopt survival strategies reflected more clearly by trade-off within each spectrum, and in some extent across spectrums. Co-ordination theory (that Rubisco- and electron-transport limited rates of photosynthesis are co-limiting) and least-coast theory (that intercellular to ambient CO2 concentration minimizes the combined costs per unit carbon assimilation, regulating maximum height and wood density) expectations matched PFT (which takes in account canopy position and light access, and life spam) variation. Our findings suggest that climate (air moisture, air temperature, light) has lower power representing these dimensions, in comparison to the PFT framework.

Distinctive bacterial communities in the rhizoplane of four tropical tree species.

PubMed

Oh, Yoon Myung; Kim, Mincheol; Lee-Cruz, Larisa; Lai-Hoe, Ang; Go, Rusea; Ainuddin, N; Rahim, Raha Abdul; Shukor, Noraini; Adams, Jonathan M

2012-11-01

It is known that the microbial community of the rhizosphere is not only influenced by factors such as root exudates, phenology, and nutrient uptake but also by the plant species. However, studies of bacterial communities associated with tropical rainforest tree root surfaces, or rhizoplane, are lacking. Here, we analyzed the bacterial community of root surfaces of four species of native trees, Agathis borneensis, Dipterocarpus kerrii, Dyera costulata, and Gnetum gnemon, and nearby bulk soils, in a rainforest arboretum in Malaysia, using 454 pyrosequencing of the 16S rRNA gene. The rhizoplane bacterial communities for each of the four tree species sampled clustered separately from one another on an ordination, suggesting that these assemblages are linked to chemical and biological characteristics of the host or possibly to the mycorrhizal fungi present. Bacterial communities of the rhizoplane had various similarities to surrounding bulk soils. Acidobacteria, Alphaproteobacteria, and Betaproteobacteria were dominant in rhizoplane communities and in bulk soils from the same depth (0-10 cm). In contrast, the relative abundance of certain bacterial lineages on the rhizoplane was different from that in bulk soils: Bacteroidetes and Betaproteobacteria, which are known as copiotrophs, were much more abundant in the rhizoplane in comparison to bulk soil. At the genus level, Burkholderia, Acidobacterium, Dyella, and Edaphobacter were more abundant in the rhizoplane. Burkholderia, which are known as both pathogens and mutualists of plants, were especially abundant on the rhizoplane of all tree species sampled. The Burkholderia species present included known mutualists of tropical crops and also known N fixers. The host-specific character of tropical tree rhizoplane bacterial communities may have implications for understanding nutrient cycling, recruitment, and structuring of tree species diversity in tropical forests. Such understanding may prove to be useful in both

Effect of initial soil properties on six-year growth of 15 tree species in tropical restoration plantings.

PubMed

Martínez-Garza, Cristina; Campo, Julio; Ricker, Martin; Tobón, Wolke

2016-12-01

In restoration plantings in degraded pastures, initial soil nutrient status may lead to differential growth of tropical tree species with diverse life history attributes and capacity for N 2 fixation. In 2006, we planted 1,440 seedlings of 15 native tree species in 16 fenced plots (30 × 30 m) in a 60-year-old pasture in Los Tuxtlas, Veracruz, Mexico, in two planting combinations. In the first year, we evaluated bulk density, pH, the concentration of organic carbon (C), total nitrogen (N), ammonia (NO3-), nitrate (NH4+), and total phosphorus (P) in the upper soil profile (0-20 cm in depth) of all plots. The first two axes of two principal component analyses explained more than 60% of the variation in soil variables: The axes were related to increasing bulk density, NO3-, NH4+, total N concentration, and pH. Average relative growth rates in diameter at the stem base of the juvenile trees after 6 years were higher for pioneer (45.7%) and N 2 -fixing species (47.6%) than for nonpioneer (34.7%) and nonfixing species (36.2%). Most N 2 -fixing species and those with the slowest growth rates did not respond to soil attributes. Tree species benefited from higher pH levels and existing litter biomass. The pioneers Ficus yoponensis , Cecropia obtusifolia , and Heliocarpus appendiculatus , and the N 2 -fixing nonpioneers Cojoba arborea , Inga sinacae , and Platymiscium dimorphandrum were promising for forest restoration on our site, given their high growth rates.

Analytical methods applied to diverse types of Brazilian propolis

PubMed Central

2011-01-01

Propolis is a bee product, composed mainly of plant resins and beeswax, therefore its chemical composition varies due to the geographic and plant origins of these resins, as well as the species of bee. Brazil is an important supplier of propolis on the world market and, although green colored propolis from the southeast is the most known and studied, several other types of propolis from Apis mellifera and native stingless bees (also called cerumen) can be found. Propolis is usually consumed as an extract, so the type of solvent and extractive procedures employed further affect its composition. Methods used for the extraction; analysis the percentage of resins, wax and insoluble material in crude propolis; determination of phenolic, flavonoid, amino acid and heavy metal contents are reviewed herein. Different chromatographic methods applied to the separation, identification and quantification of Brazilian propolis components and their relative strengths are discussed; as well as direct insertion mass spectrometry fingerprinting. Propolis has been used as a popular remedy for several centuries for a wide array of ailments. Its antimicrobial properties, present in propolis from different origins, have been extensively studied. But, more recently, anti-parasitic, anti-viral/immune stimulating, healing, anti-tumor, anti-inflammatory, antioxidant and analgesic activities of diverse types of Brazilian propolis have been evaluated. The most common methods employed and overviews of their relative results are presented. PMID:21631940

Biodiversity Can Help Prevent Malaria Outbreaks in Tropical Forests

PubMed Central

Laporta, Gabriel Zorello; de Prado, Paulo Inácio Knegt Lopez; Kraenkel, Roberto André; Coutinho, Renato Mendes; Sallum, Maria Anice Mureb

2013-01-01

Background Plasmodium vivax is a widely distributed, neglected parasite that can cause malaria and death in tropical areas. It is associated with an estimated 80–300 million cases of malaria worldwide. Brazilian tropical rain forests encompass host- and vector-rich communities, in which two hypothetical mechanisms could play a role in the dynamics of malaria transmission. The first mechanism is the dilution effect caused by presence of wild warm-blooded animals, which can act as dead-end hosts to Plasmodium parasites. The second is diffuse mosquito vector competition, in which vector and non-vector mosquito species compete for blood feeding upon a defensive host. Considering that the World Health Organization Malaria Eradication Research Agenda calls for novel strategies to eliminate malaria transmission locally, we used mathematical modeling to assess those two mechanisms in a pristine tropical rain forest, where the primary vector is present but malaria is absent. Methodology/Principal Findings The Ross–Macdonald model and a biodiversity-oriented model were parameterized using newly collected data and data from the literature. The basic reproduction number () estimated employing Ross–Macdonald model indicated that malaria cases occur in the study location. However, no malaria cases have been reported since 1980. In contrast, the biodiversity-oriented model corroborated the absence of malaria transmission. In addition, the diffuse competition mechanism was negatively correlated with the risk of malaria transmission, which suggests a protective effect provided by the forest ecosystem. There is a non-linear, unimodal correlation between the mechanism of dead-end transmission of parasites and the risk of malaria transmission, suggesting a protective effect only under certain circumstances (e.g., a high abundance of wild warm-blooded animals). Conclusions/Significance To achieve biological conservation and to eliminate Plasmodium parasites in human populations

Biodiversity can help prevent malaria outbreaks in tropical forests.

PubMed

Laporta, Gabriel Zorello; Lopez de Prado, Paulo Inácio Knegt; Kraenkel, Roberto André; Coutinho, Renato Mendes; Sallum, Maria Anice Mureb

2013-01-01

Plasmodium vivax is a widely distributed, neglected parasite that can cause malaria and death in tropical areas. It is associated with an estimated 80-300 million cases of malaria worldwide. Brazilian tropical rain forests encompass host- and vector-rich communities, in which two hypothetical mechanisms could play a role in the dynamics of malaria transmission. The first mechanism is the dilution effect caused by presence of wild warm-blooded animals, which can act as dead-end hosts to Plasmodium parasites. The second is diffuse mosquito vector competition, in which vector and non-vector mosquito species compete for blood feeding upon a defensive host. Considering that the World Health Organization Malaria Eradication Research Agenda calls for novel strategies to eliminate malaria transmission locally, we used mathematical modeling to assess those two mechanisms in a pristine tropical rain forest, where the primary vector is present but malaria is absent. The Ross-Macdonald model and a biodiversity-oriented model were parameterized using newly collected data and data from the literature. The basic reproduction number ([Formula: see text]) estimated employing Ross-Macdonald model indicated that malaria cases occur in the study location. However, no malaria cases have been reported since 1980. In contrast, the biodiversity-oriented model corroborated the absence of malaria transmission. In addition, the diffuse competition mechanism was negatively correlated with the risk of malaria transmission, which suggests a protective effect provided by the forest ecosystem. There is a non-linear, unimodal correlation between the mechanism of dead-end transmission of parasites and the risk of malaria transmission, suggesting a protective effect only under certain circumstances (e.g., a high abundance of wild warm-blooded animals). To achieve biological conservation and to eliminate Plasmodium parasites in human populations, the World Health Organization Malaria Eradication

Floating plant dominance as a stable state

PubMed Central

Scheffer, Marten; Szabó, Sándor; Gragnani, Alessandra; van Nes, Egbert H.; Rinaldi, Sergio; Kautsky, Nils; Norberg, Jon; Roijackers, Rudi M. M.; Franken, Rob J. M.

2003-01-01

Invasion by mats of free-floating plants is among the most important threats to the functioning and biodiversity of freshwater ecosystems ranging from temperate ponds and ditches to tropical lakes. Dark, anoxic conditions under thick floating-plant cover leave little opportunity for animal or plant life, and they can have large negative impacts on fisheries and navigation in tropical lakes. Here, we demonstrate that floating-plant dominance can be a self-stabilizing ecosystem state, which may explain its notorious persistence in many situations. Our results, based on experiments, field data, and models, represent evidence for alternative domains of attraction in ecosystems. An implication of our findings is that nutrient enrichment reduces the resilience of freshwater systems against a shift to floating-plant dominance. On the other hand, our results also suggest that a single drastic harvest of floating plants can induce a permanent shift to an alternative state dominated by rooted, submerged growth forms. PMID:12634429

Assessment of Air Pollution Tolerance Index of some plants to develop vertical gardens near street canyons of a polluted tropical city.

PubMed

Pandey, Ashutosh Kumar; Pandey, Mayank; Tripathi, B D

2016-12-01

The aim of the present study was to examine Air Pollution Tolerance Index (APTI) of some climber plant species to develop vertical gardens in Varanasi city which has characteristics of tall building and narrow roads. This condition results in street canyon like structure and hinders the vertical dispersal of air pollutants. We have selected 24 climber plant species which are commonly found in of Varanasi city. Chosen plants can be easily grown either in planter boxes or directly in the ground, with a vertical support they can climb on walls to form green walls or vertical garden. Air Pollution Tolerance Index (APTI) of the selected plant species was calculated and plants with higher APTI are recommended for the development of Vertical garden. Highest APTI was noted for Ipomoea palmata (25.39) followed by Aristolochia elegans (23.28), Thunbergia grandiflora (23.14), Quisqualis indica (22.42), and Clerodendrum splendens (22.36). However, lowest APTI value (8.75) was recorded for the species Hemidesmus indicus. Moreover, the linear regression analysis has revealed a high positive correlation between APTI and ascorbic acid content (R 2 =0.8837) and positive correlation between APTI and Chlorophyll content (R 2 =0.6687). On the basis of higher APTI values (greater than 17), nine species of climber plants viz. I. palmata, T. grandiflora, C. splendens, A. elegans, Q. indica, Petria volubilis, Antigonon leptopus, Cryptolepis buchuanni and Tinospora cordifolia have been recommended to develop vertical greenery systems in a compact tropical city. Copyright © 2015 Elsevier Inc. All rights reserved.

Airborne observations reveal elevational gradient in tropical forest isoprene emissions.

PubMed

Gu, Dasa; Guenther, Alex B; Shilling, John E; Yu, Haofei; Huang, Maoyi; Zhao, Chun; Yang, Qing; Martin, Scot T; Artaxo, Paulo; Kim, Saewung; Seco, Roger; Stavrakou, Trissevgeni; Longo, Karla M; Tóta, Julio; de Souza, Rodrigo Augusto Ferreira; Vega, Oscar; Liu, Ying; Shrivastava, Manish; Alves, Eliane G; Santos, Fernando C; Leng, Guoyong; Hu, Zhiyuan

2017-05-23

Isoprene dominates global non-methane volatile organic compound emissions, and impacts tropospheric chemistry by influencing oxidants and aerosols. Isoprene emission rates vary over several orders of magnitude for different plants, and characterizing this immense biological chemodiversity is a challenge for estimating isoprene emission from tropical forests. Here we present the isoprene emission estimates from aircraft eddy covariance measurements over the Amazonian forest. We report isoprene emission rates that are three times higher than satellite top-down estimates and 35% higher than model predictions. The results reveal strong correlations between observed isoprene emission rates and terrain elevations, which are confirmed by similar correlations between satellite-derived isoprene emissions and terrain elevations. We propose that the elevational gradient in the Amazonian forest isoprene emission capacity is determined by plant species distributions and can substantially explain isoprene emission variability in tropical forests, and use a model to demonstrate the resulting impacts on regional air quality.

Current trends of tropical fruit waste utilization.

PubMed

Cheok, Choon Yoong; Mohd Adzahan, Noranizan; Abdul Rahman, Russly; Zainal Abedin, Nur Hanani; Hussain, Norhayati; Sulaiman, Rabiha; Chong, Gun Hean

2018-02-11

Recent rapid growth of the world's population has increased food demands. This phenomenon poses a great challenge for food manufacturers in maximizing the existing food or plant resources. Nowadays, the recovery of health benefit bioactive compounds from fruit wastes is a research trend not only to help minimize the waste burden, but also to meet the intensive demand from the public for phenolic compounds which are believed to have protective effects against chronic diseases. This review is focused on polyphenolic compounds recovery from tropical fruit wastes and its current trend of utilization. The tropical fruit wastes include in discussion are durian (Durio zibethinus), mangosteen (Garcinia mangostana L.), rambutan (Nephelium lappaceum), mango (Mangifera indica L.), jackfruit (Artocarpus heterophyllus), papaya (Carica papaya), passion fruit (Passiflora edulis), dragon fruit (Hylocereus spp), and pineapple (Ananas comosus). Highlights of bioactive compounds in different parts of a tropical fruit are targeted primarily for food industries as pragmatic references to create novel innovative health enhancement food products. This information is intended to inspire further research ideas in areas that are still under-explored and for food processing manufacturers who would like to minimize wastes as the norm of present day industry (design) objective.

Anthropogenic disturbance reduces seed-dispersal services for myrmecochorous plants in the Brazilian Caatinga.

PubMed

Leal, Laura C; Andersen, Alan N; Leal, Inara R

2014-01-01

Anthropogenic disturbance can have important indirect effects on ecosystems by disrupting species interactions. Here we examine the effects of anthropogenic disturbance on distance dispersal by ants for the diaspores of myrmecochorous Euphorbiaceae in Brazilian Caatinga. Rates of diaspore removal and distances removed of Croton sonderianus and Jatropha mollissima were observed at 24 sites ranging from low to very high disturbance (primarily grazing by livestock, hunting and firewood collection). Despite a large number of seed-disperser ant species, there were only two species providing high-quality distance-dispersal services, Dinoponera quadriceps (40% of all observed seed removals) and Ectatomma muticum (33%). D. quadriceps was responsible for 97% of all removals >2 m, and 100% of all removals >5 m. Removal rates did not vary with disturbance for C. sonderianus (small elaiosome), but declined with increasing disturbance for J. mollissima (large elaiosome). The number of removals by Ectatomma was highest at intermediate levels of disturbance, whereas those by Dinoponera decreased systematically with increasing levels of disturbance. Mean dispersal distance was four times higher at sites experiencing low disturbance, where removals >5 m represented a third of all removal events, compared with very highly disturbed sites, where no removals >5 m were observed. Despite high overall diversity there is very limited functional redundancy in disperser ant species, resulting in low disperser resilience in relation to disturbance. This is likely to have important implications for recruitment by myrmecochorous plants, and therefore on vegetation composition and structure, at sites subject to high anthropogenic disturbance.

Dengue endemic and its impact on the gross national product of BRAZILIAN'S economy.

PubMed

Montibeler, Everlam Elias; Oliveira, Daniel Ribeiro de

2018-02-01

In history disease has caused social and economic damage. Dengue is an illness typically found in the tropics that has affected more and more people. In Brazil, according to the Brazilian Institute of Geography and Statistics (IBGE), in 2013 at least 12.9% of the population (25.8 million) reported already having had dengue in their life. So, how wide are the economic impacts that dengue's contagion has on the gross national product? Using Leontief's method, it became possible to estimate the direct and indirect impact on the workforce and output by one country. Workforce absenteeism reduced the national productiveness and welfare state where we found maximum inoperability of 0.027% and a minimum of 0.002%. This paper develops a methodology for estimation of the impact dengue has incurred in each sector of an economy; designing a ranking with sectors that have been more affected and forecasting the propagation of the endemic throughout a region. This research measures the impact of dengue on economy, the result was that the total loss of the Brazilian economy in 2013 was around BRL 1,023,174,876.83; the importance of 0.02% of the Gross Domestic Product. Copyright © 2017 Elsevier B.V. All rights reserved.

Leaf litter arthropod responses to tropical forest restoration.

PubMed

Cole, Rebecca J; Holl, Karen D; Zahawi, Rakan A; Wickey, Philipp; Townsend, Alan R

2016-08-01

Soil and litter arthropods represent a large proportion of tropical biodiversity and perform important ecosystem functions, but little is known about the efficacy of different tropical forest restoration strategies in facilitating their recovery in degraded habitats. We sampled arthropods in four 7- to 8-year-old restoration treatments and in nearby reference forests. Sampling was conducted during the wet and dry seasons using extractions from litter and pitfall samples. Restoration treatments were replicated in 50 × 50-m plots in four former pasture sites in southern Costa Rica: plantation - trees planted throughout the plot; applied nucleation/islands - trees planted in patches of different sizes; and natural regeneration - no tree planting. Arthropod abundance, measures of richness and diversity, and a number of functional groups were greater in the island treatment than in natural regeneration or plantation treatments and, in many cases, were similar to reference forest. Litter and pitfall morphospecies and functional group composition in all three restoration treatments were significantly different than reference sites, but island and plantation treatments showed more recovery than natural regeneration. Abundance and functional group diversity showed a much greater degree of recovery than community composition. Synthesis and applications: The less resource-intensive restoration strategy of planting tree islands was more effective than tree plantations in restoring arthropod abundance, richness, and functional diversity. None of the restoration strategies, however, resulted in similar community composition as reference forest after 8 years of recovery, highlighting the slow rate of recovery of arthropod communities after disturbance, and underscoring the importance of conservation of remnant forests in fragmented landscapes.

Nitrogen mass balance in the Brazilian Amazon: an update.

PubMed

Martinelli, L A; Pinto, A S; Nardoto, G B; Ometto, J P H B; Filoso, S; Coletta, L D; Ravagnani, E C

2012-08-01

The main purpose of this study is to perform a nitrogen budget survey for the entire Brazilian Amazon region. The main inputs of nitrogen to the region are biological nitrogen fixation occurring in tropical forests (7.7 Tg.yr(-1)), and biological nitrogen fixation in agricultural lands mainly due to the cultivation of a large area with soybean, which is an important nitrogen-fixing crop (1.68 Tg.yr(-1)). The input due to the use of N fertilizers (0.48 Tg.yr(-1)) is still incipient compared to the other two inputs mentioned above. The major output flux is the riverine flux, equal to 2.80 Tg.yr(-1) and export related to foodstuff, mainly the transport of soybean and beef to other parts of the country. The continuous population growth and high rate of urbanization may pose new threats to the nitrogen cycle of the region through the burning of fossil fuel and dumping of raw domestic sewage in rivers and streams of the region.

Brazilian Cerrado soil Actinobacteria ecology.

PubMed

Suela Silva, Monique; Naves Sales, Alenir; Teixeira Magalhães-Guedes, Karina; Ribeiro Dias, Disney; Schwan, Rosane Freitas

2013-01-01

A total of 2152 Actinobacteria strains were isolated from native Cerrado (Brazilian Savannah) soils located in Passos, Luminárias, and Arcos municipalities (Minas Gerais State, Brazil). The soils were characterised for chemical and microbiological analysis. The microbial analysis led to the identification of nine genera (Streptomyces, Arthrobacter, Rhodococcus, Amycolatopsis, Microbacterium, Frankia, Leifsonia, Nakamurella, and Kitasatospora) and 92 distinct species in both seasons studied (rainy and dry). The rainy season produced a high microbial population of all the aforementioned genera. The pH values of the soil samples from the Passos, Luminárias, and Arcos regions varied from 4.1 to 5.5. There were no significant differences in the concentrations of phosphorus, magnesium, and organic matter in the soils among the studied areas. Samples from the Arcos area contained large amounts of aluminium in the rainy season and both hydrogen and aluminium in the rainy and dry seasons. The Actinobacteria population seemed to be unaffected by the high levels of aluminium in the soil. Studies are being conducted to produce bioactive compounds from Actinobacteria fermentations on different substrates. The present data suggest that the number and diversity of Actinobacteria spp. in tropical soils represent a vast unexplored resource for the biotechnology of bioactives production.

Brazilian Cerrado Soil Actinobacteria Ecology

PubMed Central

Suela Silva, Monique; Naves Sales, Alenir; Teixeira Magalhães-Guedes, Karina; Ribeiro Dias, Disney; Schwan, Rosane Freitas

2013-01-01

A total of 2152 Actinobacteria strains were isolated from native Cerrado (Brazilian Savannah) soils located in Passos, Luminárias, and Arcos municipalities (Minas Gerais State, Brazil). The soils were characterised for chemical and microbiological analysis. The microbial analysis led to the identification of nine genera (Streptomyces, Arthrobacter, Rhodococcus, Amycolatopsis, Microbacterium, Frankia, Leifsonia, Nakamurella, and Kitasatospora) and 92 distinct species in both seasons studied (rainy and dry). The rainy season produced a high microbial population of all the aforementioned genera. The pH values of the soil samples from the Passos, Luminárias, and Arcos regions varied from 4.1 to 5.5. There were no significant differences in the concentrations of phosphorus, magnesium, and organic matter in the soils among the studied areas. Samples from the Arcos area contained large amounts of aluminium in the rainy season and both hydrogen and aluminium in the rainy and dry seasons. The Actinobacteria population seemed to be unaffected by the high levels of aluminium in the soil. Studies are being conducted to produce bioactive compounds from Actinobacteria fermentations on different substrates. The present data suggest that the number and diversity of Actinobacteria spp. in tropical soils represent a vast unexplored resource for the biotechnology of bioactives production. PMID:23555089

Tropical vegetation evidence for rapid sea level changes associated with Heinrich Events

NASA Astrophysics Data System (ADS)

González, Catalina; Dupont, Lydie M.

2010-03-01

A Cariaco Basin pollen record shows the development of tropical salt marshes during marine isotope stage 3. Rapid and abrupt expansions of salt marsh vegetation in tropical South America are associated with north Atlantic Heinrich Events stadials (HE-stadials). Intervals of salt marsh expansion have an internal structure, which consists of a recurrent alternation of species that starts with pollen increments of Chenopodiaceae, that are followed by increments of grasses, and subsequently by increments of Cyperaceae. This pattern suggests a successional process that is determined by the close relationship between sea-level and plant community dynamics. The salt tolerant Chenopodiaceae, indicate hypersaline intertidal environments, which were most likely promoted by extremely dry atmospheric conditions. Rapid sea-level rise characterizes the onset of HE-stadials, causing the continued recruitment of pioneer species, which are the only ones tolerating rapid rates of disturbance. Once sea-level rise decelerates, marsh plants are able to trap and stabilize sediments, favouring the establishment of more competitive species. These results add to the scarce knowledge on the dynamics of tropical salt marsh ecosystems, and provide independent paleoclimatic evidence on sea-level changes following Antarctic climate variability.

Soil macrofauna and litter nutrients in three tropical tree plantations on a disturbed site in Puerto Rico.

Treesearch

Matthew W. Warren; Xiaoming Zou

2002-01-01

Tree plantations are increasingly common in tropical landscapes due to their multiple uses. Plantations vary in structure and composition, and these variations may alter soil fauna communities. Recent studies have demonstrated the important role of soil fauna in the regulation of plant litter decomposition in the tropics. However, little is known about how plantation...

Export-oriented deforestation in Mato Grosso: harbinger or exception for other tropical forests?

PubMed Central

DeFries, Ruth; Herold, Martin; Verchot, Louis; Macedo, Marcia N.; Shimabukuro, Yosio

2013-01-01

The Brazilian state of Mato Grosso was a global deforestation hotspot in the early 2000s. Deforested land is used predominantly to produce meat for distal consumption either through cattle ranching or soya bean for livestock feed. Deforestation declined dramatically in the latter part of the decade through a combination of market forces, policies, enforcement and improved monitoring. This study assesses how representative the national-level drivers underlying Mato Grosso's export-oriented deforestation are in other tropical forest countries based on agricultural exports, commercial agriculture and urbanization. We also assess how pervasive the governance and technical monitoring capacity that enabled Mato Grosso's decline in deforestation is in other countries. We find that between 41 and 54 per cent of 2000–2005 deforestation in tropical forest countries (other than Brazil) occurred in countries with drivers similar to Brazil. Very few countries had national-level governance and capacity similar to Brazil. Results suggest that the ecological, hydrological and social consequences of land-use change for export-oriented agriculture as discussed in this Theme Issue were applicable in about one-third of all tropical forest countries in 2000–2005. However, the feasibility of replicating Mato Grosso's success with controlling deforestation is more limited. Production landscapes to support distal consumption similar to Mato Grosso are likely to become more prevalent and are unlikely to follow a land-use transition model with increasing forest cover. PMID:23610176

[Railroads, disease, and tropical medicine in Brazil under the First Republic].

PubMed

Benchimol, Jaime Larry; da Silva, André Felipe Cândido

2008-01-01

The article explores the impact of malaria on infrastructure works--above all, railroads--under the republican drive towards modernization. Railways helped tie the territory together and foster the symbolic and material expansion of the Brazilian nation. The scientists entrusted with vanquishing such epidemic outbreaks did not just conduct campaigns; they also undertook painstaking observations of aspects of the disease, including its relations to hosts and the environment, thus contributing to the production of new knowledge of malaria and to the institutionalization of a new field in Brazil, then taking root in Europe's colonies: "tropical medicine." The article shows the ties between these innovations (especially the theory of domiciliary infection) and the sanitary campaigns that helped the railways, which in the 1920s were followed by a new phase in Brazil's anti-malaria efforts.

Staying cool: preadaptation to temperate climates required for colonising tropical alpine-like environments.

PubMed

Gehrke, Berit

2018-01-01

Plant species tend to retain their ancestral ecology, responding to temporal, geographic and climatic changes by tracking suitable habitats rather than adapting to novel conditions. Nevertheless, transitions into different environments or biomes still seem to be common. Especially intriguing are the tropical alpine-like areas found on only the highest mountainous regions surrounded by tropical environments. Tropical mountains are hotspots of biodiversity, often with striking degrees of endemism at higher elevations. On these mountains, steep environmental gradients and high habitat heterogeneity within small spaces coincide with astounding species diversity of great conservation value. The analysis presented here shows that the importance of in situ speciation in tropical alpine-like areas has been underestimated. Additionally and contrary to widely held opinion, the impact of dispersal from other regions with alpine-like environments is relatively minor compared to that of immigration from other biomes with a temperate (but not alpine-like) climate. This suggests that establishment in tropical alpine-like regions is favoured by preadaptation to a temperate, especially aseasonal, freezing regime such as the cool temperate climate regions in the Tropics. Furthermore, emigration out of an alpine-like environment is generally rare, suggesting that alpine-like environments - at least tropical ones - are species sinks.

Road-networks, a practical indicator of human impacts on biodiversity in Tropical forests

NASA Astrophysics Data System (ADS)

Hosaka, T.; Yamada, T.; Okuda, T.

2014-02-01

Tropical forests sustain the most diverse plants and animals in the world, but are also being lost most rapidly. Rapid assessment and monitoring using remote sensing on biodiversity of tropical forests is needed to predict and evaluate biodiversity loss by human activities. Identification of reliable indicators of forest biodiversity and/or its loss is an urgent issue. In the present paper, we propose the density of road networks in tropical forests can be a good and practical indicator of human impacts on biodiversity in tropical forests through reviewing papers and introducing our preliminary survey in peninsular Malaysia. Many previous studies suggest a strong negative impact of forest roads on biodiversity in tropical rainforests since they changes microclimate, soil properties, drainage patterns, canopy openness and forest accessibility. Moreover, our preliminary survey also showed that even a narrow logging road (6 m wide) significantly lowered abundance of dung beetles (well-known bio-indicator in biodiversity survey in tropical forests) near the road. Since these road networks are readily to be detected with remote sensing approach such as aerial photographs and Lider, regulation and monitoring of the road networks using remote sensing techniques is a key to slow down the rate of biodiversity loss due to forest degradation in tropical forests.

Staying cool: preadaptation to temperate climates required for colonising tropical alpine-like environments

PubMed Central

Gehrke, Berit

2018-01-01

Abstract Plant species tend to retain their ancestral ecology, responding to temporal, geographic and climatic changes by tracking suitable habitats rather than adapting to novel conditions. Nevertheless, transitions into different environments or biomes still seem to be common. Especially intriguing are the tropical alpine-like areas found on only the highest mountainous regions surrounded by tropical environments. Tropical mountains are hotspots of biodiversity, often with striking degrees of endemism at higher elevations. On these mountains, steep environmental gradients and high habitat heterogeneity within small spaces coincide with astounding species diversity of great conservation value. The analysis presented here shows that the importance of in situ speciation in tropical alpine-like areas has been underestimated. Additionally and contrary to widely held opinion, the impact of dispersal from other regions with alpine-like environments is relatively minor compared to that of immigration from other biomes with a temperate (but not alpine-like) climate. This suggests that establishment in tropical alpine-like regions is favoured by preadaptation to a temperate, especially aseasonal, freezing regime such as the cool temperate climate regions in the Tropics. Furthermore, emigration out of an alpine-like environment is generally rare, suggesting that alpine-like environments – at least tropical ones – are species sinks. PMID:29706788

Anti-Streptococcal activity of Brazilian Amazon Rain Forest plant extracts presents potential for preventive strategies against dental caries

PubMed Central

da SILVA, Juliana Paola Corrêa; de CASTILHO, Adriana Lígia; SARACENI, Cíntia Helena Couri; DÍAZ, Ingrit Elida Collantes; PACIÊNCIA, Mateus Luís Barradas; SUFFREDINI, Ivana Barbosa

2014-01-01

Caries is a global public health problem, whose control requires the introduction of low-cost treatments, such as strong prevention strategies, minimally invasive techniques and chemical prevention agents. Nature plays an important role as a source of new antibacterial substances that can be used in the prevention of caries, and Brazil is the richest country in terms of biodiversity. Objective In this study, the disk diffusion method (DDM) was used to screen over 2,000 Brazilian Amazon plant extracts against Streptococcus mutans. Material and Methods Seventeen active plant extracts were identified and fractionated. Extracts and their fractions, obtained by liquid-liquid partition, were tested in the DDM assay and in the microdilution broth assay (MBA) to determine their minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs). The extracts were also subjected to antioxidant analysis by thin layer chromatography. Results EB271, obtained from Casearia spruceana, showed significant activity against the bacterium in the DDM assay (20.67±0.52 mm), as did EB1129, obtained from Psychotria sp. (Rubiaceae) (15.04±2.29 mm). EB1493, obtained from Ipomoea alba, was the only extract to show strong activity against Streptococcus mutans (0.08 mg/mL

Molecular marker-based genetic diversity analysis of scantly studied Brazilian accessions of a medicinal plant, Morinda citrifolia L. (noni).

PubMed

Bordallo, P N; Monteiro, A M R; Sousa, J A; Aragão, F A S

2017-02-23

Morinda citrifolia L., commonly known as noni, has been used for the treatment of various diseases for over two centuries. It was introduced and widely disseminated in Brazil because of its high market value and ease of adaptation to the soil and climatic conditions of the country. The aim of this study was to estimate the genetic variability of noni accessions from the collection of Embrapa Agroindústria Tropical in Brazil. We evaluated 36 plants of the 13 accessions of noni from the germplasm collection of M. citrifolia. Several methods of DNA extraction were tested. After definition of the method, the DNA of each sample was subjected to polymerase chain reactions using 20 random amplified polymorphic DNA primers. The band patterns on agarose gel were converted into a binary data matrix, which was used to estimate the genetic distances between the plants and to perform the cluster analyses. Of the total number of markers used in this study, 125 (81.1%) were polymorphic. The genetic distances between the genotypes ranged from 0.04 to 0.49. Regardless of the high number of polymorphic bands, the genetic variability of the noni plants evaluated was low since most of the genotypes belonged to the same cluster as shown by the dendrogram and Tocher's cluster analysis. The low genetic diversity among the studied noni individuals indicates that additional variability should be introduced in the germplasm collection of noni by gathering new individuals and/or by hybridizing contrasting individuals.

Thermal acclimation of leaf respiration of tropical trees and lianas: response to experimental canopy warming, and consequences for tropical forest carbon balance.

PubMed

Slot, Martijn; Rey-Sánchez, Camilo; Gerber, Stefan; Lichstein, Jeremy W; Winter, Klaus; Kitajima, Kaoru

2014-09-01

Climate warming is expected to increase respiration rates of tropical forest trees and lianas, which may negatively affect the carbon balance of tropical forests. Thermal acclimation could mitigate the expected respiration increase, but the thermal acclimation potential of tropical forests remains largely unknown. In a tropical forest in Panama, we experimentally increased nighttime temperatures of upper canopy leaves of three tree and two liana species by on average 3 °C for 1 week, and quantified temperature responses of leaf dark respiration. Respiration at 25 °C (R25 ) decreased with increasing leaf temperature, but acclimation did not result in perfect homeostasis of respiration across temperatures. In contrast, Q10 of treatment and control leaves exhibited similarly high values (range 2.5-3.0) without evidence of acclimation. The decrease in R25 was not caused by respiratory substrate depletion, as warming did not reduce leaf carbohydrate concentration. To evaluate the wider implications of our experimental results, we simulated the carbon cycle of tropical latitudes (24°S-24°N) from 2000 to 2100 using a dynamic global vegetation model (LM3VN) modified to account for acclimation. Acclimation reduced the degree to which respiration increases with climate warming in the model relative to a no-acclimation scenario, leading to 21% greater increase in net primary productivity and 18% greater increase in biomass carbon storage over the 21st century. We conclude that leaf respiration of tropical forest plants can acclimate to nighttime warming, thereby reducing the magnitude of the positive feedback between climate change and the carbon cycle. © 2014 John Wiley & Sons Ltd.

Governance in managing public health resources in Brazilian municipalities.

PubMed

Avelino, George; Barberia, Lorena G; Biderman, Ciro

2014-09-01

This study contributes to the health governance discussion by presenting a new data set that allows for comparisons of the management of health resources among Brazilian municipalities. Research on Brazil is particularly important as the provision of health services was decentralized in 1988 and since then municipalities have been given greater responsibilities for the management of fiscal resources for public health service provision. Based on detailed information on corruption practices (such as over-invoicing, illegal procurement and fake receipts) from audit reports of health programmes in 980 randomly selected Brazilian municipalities, this study deepens understanding of the relationship between health governance institutions and the incidence of corruption at the local level by exploring the extent to which horizontal and vertical accountabilities contribute to reducing the propensity of municipal government officials to divert public health resources for private gain. The results of our multiple regression analysis suggest that the experience of health municipal councils is correlated with reductions in the incidence of corruption in public health programmes. This impact is significant over time, with each additional year of health council experience reducing corruption incidence levels by 2.1% from baseline values. The findings reported in this study do not rely on the subjectivity of corruption measures which usually conflate the actual incidence of corruption with its perception by informants. Based on our results, we provide recommendations that can assist policy makers to reduce corruption. Published by Oxford University Press in association with The London School of Hygiene and Tropical Medicine © The Author 2013; all rights reserved.

Malaria and other febrile diseases among travellers: the experience of a reference centre located outside the Brazilian Amazon Region.

PubMed

Dotrário, Andréa Beltrami; Menon, Lucas José Bazzo; Bollela, Valdes Roberto; Martinez, Roberto; de Almeida E Araújo, Daniel Cardoso; da Fonseca, Benedito Antônio Lopes; Santana, Rodrigo de C

2016-05-26

Malaria is endemic in countries located in tropical and sub-tropical regions. The increasing flow of domestic and international travellers has made malaria a relevant health problem even in non-endemic regions. Malaria has been described as the main diagnosis among travellers presenting febrile diseases after returning from tropical countries. In Brazil, malaria transmission occurs mainly in the Amazon region. Outside this area, malaria transmission is of low magnitude. This cross-sectional study aimed to describe the experience in the diagnosis of malaria in a reference centre located outside the Brazilian Amazon Region, emphasizing the differences in clinical and laboratory markers between cases of malaria and those of other febrile diseases (OFD). Medical charts from adult patients (≥18 years) who underwent a thick smear test (TST) for malaria, between January 2001 and December 2014, were retrospectively reviewed. A total of 458 cases referred to perform the TST were included. Malaria was diagnosed in 193 (42 %) episodes. The remaining 265 episodes (58 %) were grouped as OFD. The majority of malaria episodes were acquired in the Brazilian Amazon Region. The median time between the onset of symptoms and the TST was 7 days. Only 53 (11.5 %) episodes were tested within the first 48 h after symptom onset. Comparing malaria with OFD, jaundice, nausea, vomiting, and reports of fever were more prevalent in the malaria group. Low platelet count and elevated bilirubin levels were also related to the diagnosis of malaria. The results indicate that outside the endemic area travellers presenting febrile disease suspected of being malaria underwent diagnostic test after considerable delay. The reporting of fever combined with a recent visit to an endemic area should promptly evoke the hypothesis of malaria. In these cases, specific diagnostic tests for malaria should be a priority. For cases that jump this step, the presence of elevated bilirubin or thrombocytopaenia

Pervasive phosphorus limitation of tree species but not communities in tropical forests

NASA Astrophysics Data System (ADS)

Turner, Benjamin L.; Brenes-Arguedas, Tania; Condit, Richard

2018-03-01

Phosphorus availability is widely assumed to limit primary productivity in tropical forests, but support for this paradigm is equivocal. Although biogeochemical theory predicts that phosphorus limitation should be prevalent on old, strongly weathered soils, experimental manipulations have failed to detect a consistent response to phosphorus addition in species-rich lowland tropical forests. Here we show, by quantifying the growth of 541 tropical tree species across a steep natural phosphorus gradient in Panama, that phosphorus limitation is widespread at the level of individual species and strengthens markedly below a threshold of two parts per million exchangeable soil phosphate. However, this pervasive species-specific phosphorus limitation does not translate into a community-wide response, because some species grow rapidly on infertile soils despite extremely low phosphorus availability. These results redefine our understanding of nutrient limitation in diverse plant communities and have important implications for attempts to predict the response of tropical forests to environmental change.

Altitude affects the reproductive performance in monoicous and dioicous bryophytes: examples from a Brazilian Atlantic rainforest

PubMed Central

Maciel-Silva, Adaíses S.; Marques Valio, Ivany F.; Rydin, Håkan

2012-01-01

Background and aims Short life cycles and trade-offs linked to breeding systems make bryophytes good models for the study of plant reproductive strategies. Our aim was to test if differences in sexual reproductive performance of bryophytes in tropical rainforests are driven by the breeding system of the species (monoicous or dioicous) or are mainly affected by the habitat. Methodology The reproductive performance (sexual branches, gametangia (sex organs), fertilization and sporophyte production) of 11 species was repeatedly monitored and analysed from populations at sea-level and montane sites of a Brazilian Atlantic rainforest over 15 months. Principal results Monoicous species had the highest reproductive performance, particularly for sexual branches, fertilized gametangia and sporophyte production. Species at the sea-level site produced more sexual branches and had more female-biased sex ratios of gametangia than species in the montane site. Fertilizations were more frequent at the montane site, but sporophyte frequency was similar between the two sites. Fertilization tended to occur mostly in the periods of heavy rain (October to December). Conclusions Breeding system is not the only major influence on the reproductive performance of bryophytes. We show that habitat is also an important factor determining life-history differentiation. Female-biased sex ratios and low rates of fertilization are seen to be compensated for by high production of reproductive structures at the initial phases of the reproductive cycle. PMID:22822422

The value of trophic interactions for ecosystem function: dung beetle communities influence seed burial and seedling recruitment in tropical forests

PubMed Central

Bardgett, Richard D.; Louzada, Julio; Barlow, Jos

2016-01-01

Anthropogenic activities are causing species extinctions, raising concerns about the consequences of changing biological communities for ecosystem functioning. To address this, we investigated how dung beetle communities influence seed burial and seedling recruitment in the Brazilian Amazon. First, we conducted a burial and retrieval experiment using seed mimics. We found that dung beetle biomass had a stronger positive effect on the burial of large than small beads, suggesting that anthropogenic reductions in large-bodied beetles will have the greatest effect on the secondary dispersal of large-seeded plant species. Second, we established mesocosm experiments in which dung beetle communities buried Myrciaria dubia seeds to examine plant emergence and survival. Contrary to expectations, we found that beetle diversity and biomass negatively influenced seedling emergence, but positively affected the survival of seedlings that emerged. Finally, we conducted germination trials to establish the optimum burial depth of experimental seeds, revealing a negative relationship between burial depth and seedling emergence success. Our results provide novel evidence that seed burial by dung beetles may be detrimental for the emergence of some seed species. However, we also detected positive impacts of beetle activity on seedling recruitment, which are probably because of their influence on soil properties. Overall, this study provides new evidence that anthropogenic impacts on dung beetle communities could influence the structure of tropical forests; in particular, their capacity to regenerate and continue to provide valuable functions and services. PMID:27928036

The value of trophic interactions for ecosystem function: dung beetle communities influence seed burial and seedling recruitment in tropical forests.

PubMed

Griffiths, Hannah M; Bardgett, Richard D; Louzada, Julio; Barlow, Jos

2016-12-14

Anthropogenic activities are causing species extinctions, raising concerns about the consequences of changing biological communities for ecosystem functioning. To address this, we investigated how dung beetle communities influence seed burial and seedling recruitment in the Brazilian Amazon. First, we conducted a burial and retrieval experiment using seed mimics. We found that dung beetle biomass had a stronger positive effect on the burial of large than small beads, suggesting that anthropogenic reductions in large-bodied beetles will have the greatest effect on the secondary dispersal of large-seeded plant species. Second, we established mesocosm experiments in which dung beetle communities buried Myrciaria dubia seeds to examine plant emergence and survival. Contrary to expectations, we found that beetle diversity and biomass negatively influenced seedling emergence, but positively affected the survival of seedlings that emerged. Finally, we conducted germination trials to establish the optimum burial depth of experimental seeds, revealing a negative relationship between burial depth and seedling emergence success. Our results provide novel evidence that seed burial by dung beetles may be detrimental for the emergence of some seed species. However, we also detected positive impacts of beetle activity on seedling recruitment, which are probably because of their influence on soil properties. Overall, this study provides new evidence that anthropogenic impacts on dung beetle communities could influence the structure of tropical forests; in particular, their capacity to regenerate and continue to provide valuable functions and services. © 2016 The Author(s).

Factors Controlling Fluxes of Nitrous Oxide (N-N2O) in AN Upland Tropical Forest (atlantic Forest) - Brazil, Rio de Janeiro

NASA Astrophysics Data System (ADS)

Perry, I.; de Mello, W. Z.; McDowell, W. H.

2010-12-01

Atlantic Forest is located along the Brazilian coast and inland to Paraguay and Argentina. It has been largely devastated years ago by anthropogenic activities, such as agriculture and urbanization. Only ten percent of its original area remains (100.000 km2), which is concentrated on high lands. Atlantic Forest is a biodiversity hotspot that receives high nitrogen (N) input through atmospheric deposition in forests of Rio de Janeiro; however, not much is known about the consequences of this N addition. This study has been conducted in the Serra dos Orgaos National Park (SONP - 22.782 km2) located a few kilometers Northeast of Rio de Janeiro Metropolitan Region, Sea Mountain. The forest, characterized as Tropical Moist Forest, is rigorously protected. Vegetation varies along the altitudinal gradient, where the highest peak is at 2,200m asl. Previous studies reported that N atmospheric deposition in SONP varies from 14 to 24 kg ha-1 year-1. The high N deposition on tropical forests increases emission to the atmosphere of N-N2O, a greenhouse gas. There is a lack of N-N2O measurements in tropical forests, mainly in upland tropical forests. We present fluxes of N-N2O from a Brazilian upland tropical forest, and assess the factors controlling N-N2O fluxes. Samples were collected from eight grids (48m2), between 330-451m asl (Subtropical vegetation) and eight grids between 1137-1251m (Montane vegetation), during the dry (July 2008) and wet (Jan-Feb 2009) seasons. Daily, N-N2O (N=372) and soil (N=185) were collected. Nitrous oxide emission was 0,7 (lower altitude) and 0,3 kgN ha-1 year-1 (higher altitude), which is lower than in other upland tropical forests, such as Luquillo Experimental Forest, Puerto Rico, where atmospheric N input (4 kg ha-1 year-1) is not as high as in SONP. Water filled pore space, soil temperature, phosphorus and C:N are the main factors controlling N-N2O fluxes. Manganese was not a good indicator for presence or absence of N-N2O. Higher N-N2O

CHANGES IN EARTHWORM DENSITY AND COMMUNITY STRUCTURE DURING SECONDARY SUCCESSION IN ABANDONED TROPICAL PASTURES

Treesearch

Xiaoming Zou; Grizelle Gonzalez

1997-01-01

Plant community succession alters the quantity and chemistry of organic inputs to soils. These differences in organic input may trigger changes in soil fertility and fauna1 activity. We examined earthworm density and community structure along a successional sequence of plant communities in abandoned tropical pastures in Puerto Rico. The chronological sequence of these...

Anthelmintic efficacy of five tropical native Australian plants against Haemonchus contortus and Trichostrongylus colubriformis in experimentally infected goats (Capra hircus).

PubMed

Moreno, F C; Gordon, I J; Knox, M R; Summer, P M; Skerrat, L F; Benvenutti, M A; Saumell, C A

2012-06-08

The study of the anthelmintic properties of plants rich in plant secondary metabolites can provide ecologically sound methods for the treatment of parasites on grazing animals. The purpose of the present study was to evaluate the anthelmintic effect of five tropical native Australian plant species rich in plant secondary metabolites on adult Haemonchus contortus and Trichostrongylus colubriformis in experimentally infected goats. Thirty young, nematode-free goats were infected with 2500 H. contortus and 5000 T. colubriformis infective larvae thrice weekly for a week (day 1-7 of the experiment). On day 27 after first infection, the goats were allocated into six groups of five animals per group. From day 28 to day 35, fresh leaves from Acacia salicina, Acacia nilotica, Eucalyptus corymbia, Casuarina cunninghamiana and Eucalyptus drepanophylla were included in the goats diet. Five groups were offered leaves from one of these plant species and one group, the untreated control, received only the basal diet formulated with 20% Medicago sativa and 80% Avena sativa. Following plant material administration, the goats were monitored daily until day 40 and then slaughtered on day 41. Total faecal worm egg output, total production of larvae recovered from faecal cultures, total post-mortem worm burdens and the per capita fecundity of female worms were estimated. The toxicity of the plant species for the goats was measured by histopathological analyses of liver and kidney samples. Results showed that goats feeding on the plant material rich in plant secondary metabolites had significantly lower egg output compared to the control goats (P<0.05). A similar response was found for larval production in both H. contortus and T. colubriformis supporting that egg output was affected in both species. Although the total worm burdens were not affected by the plant material (P>0.05), the per capita fecundity was significantly reduced by E. corymbia, A. nilotica and A. salicina (P<0.05). No

Antitrypanosomal, antileishmanial and cytotoxic activities of Brazilian red propolis and plant resin of Dalbergia ecastaphyllum (L) Taub.

PubMed

Regueira-Neto, Marcos da Silveira; Tintino, Saulo Relison; Rolón, Miriam; Coronal, Cathia; Vega, Maria C; de Queiroz Balbino, Valdir; de Melo Coutinho, Henrique Douglas

2018-04-14

The treatment for leishmaniasis and Chagas disease can be hard and painful, such that many patients give up on the treatment. In order to find an alternative path for the treatment of these diseases, researchers are using natural products to fight these parasites. The aim of this study was to evaluate the antiprotozoan and cytotoxic activities of red propolis samples collected from different Brazilian states and seasons whilst searching for possible activity differences. We also compared the red propolis results with the ones obtained for the plant resin extract collected from Dalbergia ecastaphyllum trees. The hydroethanolic red propolis extracts from Pernambuco and Alagoas, and the D. ecastaphyllum resin were evaluated regarding their antileishmanial, antitrypanosomal and cytotoxic activity. All extracts showed antiprotozoan and cytotoxic activity. RP-PER showed to be more cytotoxic against protozoan parasites and fibroblast cells. All propolis extracts showed a higher cytotoxic activity when compared to resin extracts. The propolis sample collected in Pernambuco during the rainy season killed the parasites with lower concentrations than the sample collected in the dry season. The IC 50 observed against the parasites could be used without high fibroblast cell damage. Copyright © 2018 Elsevier Ltd. All rights reserved.

Incised channel fills containing conifers indicate that seasonally dry vegetation dominated Pennsylvanian tropical lowlands

USGS Publications Warehouse

Falcon-Lang, H. J.; Nelson, W.J.; Elrick, S.; Looy, C.V.; Ames, P.R.; DiMichele, W.A.

2009-01-01

The idea that the Pennsylvanian tropical lowlands were temporally dominated by rainforest (i.e., the Coal Forest) is deeply ingrained in the literature. Here we challenge two centuries of research by suggesting that this concept is based on a taphonomic artifact, and that seasonally dry vegetation dominated instead. This controversial finding arises from the discovery of a new middle Pennsylvanian (Moscovian) fossil plant assemblage in southeast Illinois, United States. The assemblage, which contains xerophytic walchian conifers, occurs in channels incised into a calcic Vertisol below the Baker Coal. These plants grew on seasonally dry tropical lowlands inferred to have developed during a glacial phase. This xerophytic flora differs markedly from that of the typical clubmoss-dominated Coal Forest developed during deglaciation events. Although preserved only very rarely, we argue that such xerophytic floras were temporally as dominant, and perhaps more dominant, than the iconic Coal Forests, which are overrepresented in the fossil record due to taphonomic megabias. These findings require the iconography of Pennsylvanian tropical lowlands to be redrawn. ?? 2009 Geological Society of America.

Phytoremediation potential and ecological and phenological changes of native pioneer plants from weathered oil spill-impacted sites at tropical wetlands.

PubMed

Palma-Cruz, Felipe de J; Pérez-Vargas, Josefina; Rivera Casado, Noemí Araceli; Gómez Guzmán, Octavio; Calva-Calva, Graciano

2016-08-01

Pioneer native plant species from weathered oil spill-affected sites were selected to study their potential for phytoremediation on the basis of their ecological and phenological changes during the phytoremediation process. Experiments were conducted in field and in greenhouse. In field, native plants from aged oil spill-impacted sites with up 400 g of weathered petroleum hydrocarbons per kilogram soil were selected. In the impacted sites, the principal dominant plant species with potential for hydrocarbons removal were Cyperus laxus, Cyperus esculentus, and Ludwigia peploides. In greenhouse, the phenology of the selected plant species was drastically affected by the hydrocarbons level above 325 g total petroleum hydrocarbons (TPH) per kilogram soil after 2 years of phytoremediation of soils from the aged oil spill-impacted sites. From the phytoremediation treatments, a mix-culture of C. laxus, C. esculentus, and L. peploides in soil containing 325 g TPH/kg soil, from which 20.3 % were polyaromatic hydrocarbons (PAH) and 34.2 % were asphaltenes (ASF), was able to remove up 93 % of the TPH, while in unvegetated soil the TPH removal was 12.6 %. Furthermore, evaluation of the biodiversity and life forms of plant species in the impacted sites showed that phytoremediation with C. esculentus, alone or in a mix-culture with C. laxus and L. peploides, reduces the TPH to such extent that the native plant community was progressively reestablished by replacing the cultivated species resulting in the ecological recovery of the affected soil. These results demonstrate that native Cyperus species from weathered oil spill-affected sites, specifically C. esculentus and C. laxus, alone or in a mix-culture, have particular potential for phytoremediation of soils from tropical wetlands contaminated with weathered oil hydrocarbons.

Accumulation and long-term decline of radiocaesium contamination in tropical fruit trees

NASA Astrophysics Data System (ADS)

Anjos, R. M.; Mosquera, B.; Carvalho, C.; Sanches, N.; Bastos, J.; Gomes, P. R. S.; Macario, K.

2007-09-01

The accumulation of 137Cs, 40K and NH 4+ in several organs of tropical plants species were studied through measurements of its concentrations from mango, avocado, guava, papaya, banana and chili pepper trees. Our goal was to infer their differences in the uptake and translocation of such ions to the aboveground plant parts and to establish the suitability of using radiocaesium as a tracer for the plant uptake of nutrients. The results indicate Cs + is better tracer for K + as it is for NH 4+.

Draft genome sequence of bitter gourd (Momordica charantia), a vegetable and medicinal plant in tropical and subtropical regions.

PubMed

Urasaki, Naoya; Takagi, Hiroki; Natsume, Satoshi; Uemura, Aiko; Taniai, Naoki; Miyagi, Norimichi; Fukushima, Mai; Suzuki, Shouta; Tarora, Kazuhiko; Tamaki, Moritoshi; Sakamoto, Moriaki; Terauchi, Ryohei; Matsumura, Hideo

2017-02-01

Bitter gourd (Momordica charantia) is an important vegetable and medicinal plant in tropical and subtropical regions globally. In this study, the draft genome sequence of a monoecious bitter gourd inbred line, OHB3-1, was analyzed. Through Illumina sequencing and de novo assembly, scaffolds of 285.5 Mb in length were generated, corresponding to ∼84% of the estimated genome size of bitter gourd (339 Mb). In this draft genome sequence, 45,859 protein-coding gene loci were identified, and transposable elements accounted for 15.3% of the whole genome. According to synteny mapping and phylogenetic analysis of conserved genes, bitter gourd was more related to watermelon (Citrullus lanatus) than to cucumber (Cucumis sativus) or melon (C. melo). Using RAD-seq analysis, 1507 marker loci were genotyped in an F2 progeny of two bitter gourd lines, resulting in an improved linkage map, comprising 11 linkage groups. By anchoring RAD tag markers, 255 scaffolds were assigned to the linkage map. Comparative analysis of genome sequences and predicted genes determined that putative trypsin-inhibitor and ribosome-inactivating genes were distinctive in the bitter gourd genome. These genes could characterize the bitter gourd as a medicinal plant. © The Author 2016. Published by Oxford University Press on behalf of Kazusa DNA Research Institute.

[Native plant resources to optimize the performances of forest rehabilitation in Mediterranean and tropical environment: some examples of nursing plant species that improve the soil mycorrhizal potential].

PubMed

Duponnois, Robin; Ramanankierana, Heriniaina; Hafidi, Mohamed; Baohanta, Rondro; Baudoin, Ezékiel; Thioulouse, Jean; Sanguin, Hervé; Bâ, Amadou; Galiana, Antoine; Bally, René; Lebrun, Michel; Prin, Yves

2013-01-01

The overexploitation of natural resources, resulting in an increased need for arable lands by local populations, causes a serious dysfunction in the soil's biological functioning (mineral deficiency, salt stress, etc.). This dysfunction, worsened by the climatic conditions (drought), requires the implementation of ecological engineering strategies allowing the rehabilitation of degraded areas through the restoration of essential ecological services. The first symptoms of weathering processes of soil quality in tropical and Mediterranean environments result in an alteration of the plant cover structure with, in particular, the pauperization of plant species diversity and abundance. This degradation is accompanied by a weakening of soils and an increase of the impact of erosion on the surface layer resulting in reduced fertility of soils in terms of their physicochemical characteristics as well as their biological ones (e.g., soil microbes). Among the microbial components particularly sensitive to erosion, symbiotic microorganisms (rhizobia, Frankia, mycorrhizal fungi) are known to be key components in the main terrestrial biogeochemical cycles (C, N and P). Many studies have shown the importance of the management of these symbiotic microorganisms in rehabilitation and revegetation strategies of degraded environments, but also in improving the productivity of agrosystems. In particular, the selection of symbionts and their inoculation into the soil were strongly encouraged in recent decades. These inoculants were selected not only for their impact on the plant, but also for their ability to persist in the soil at the expense of the residual native microflora. The performance of this technique was thus evaluated on the plant cover, but its impact on soil microbial characteristics was totally ignored. The role of microbial diversity on productivity and stability (resistance, resilience, etc.) of eco- and agrosystems has been identified relatively recently and has led

Clinical and laboratory features of HTLV-I asymptomatic carriers and patients with HTLV-I-associated myelopathy/tropical spastic paraparesis from the Brazilian Amazon

PubMed Central

Takatani, Massanobu; Crispim, Myuki Esashika; Fraiji, Nelson; Stefani, Mariane Martins Araujo; Kiesslich, Dagmar

2017-01-01

ABSTRACT Clinical and laboratory parameters including blood and cerebrospinal fluid (CSF) neopterin were investigated in human-T-lymphotropic-virus-type-I associated-myelopathy/tropical-spastic-paraparesis-HAM/TSP and in HTLV-I carriers. HAM/TSP (n = 11, 2 males/9 females, median age = 48 years), recently diagnosed HTLV-I carriers (n = 21, 15 females/6 males, median age = 44 years), healthy individuals (n = 20, 10 males/10 females, median age = 34.6 years) from the Brazilian Amazon (Manaus, Amazonas State) were investigated. Neopterin was measured (IBL ELISA Neopterin, Germany) in serum samples of all the participants, in CSF of 9 HAM/TSP patients as well as in 6 carriers. In HAM/TSP patients, CSF cell counts, protein and glucose were measured, the Osame’s motor-disability-score/OMDS was determined, and brain/spinal cord magnetic-resonance-imaging (MRI) was performed. HAM/TSP patients had normal CSF glucose, leukocyte counts; and normal protein levels predominated. Brain-MRI showed white-matter lesions in 7 out of 11 HAM/TSP patients. OMDS varied from 2-8: 9 were able to walk, 2 were wheel-chair-users. The median serum neopterin concentration in HAM/TSP patients was 6.6 nmol/ L; min. 2.8- max. 12.5 nmol/ L); was lower in carriers (4.3 nmol/L; min. 2.7- max. 7.2 nmol/ L) as well as in healthy participants (4.7 nmol/ L; min. 2.7- max. 8.0 nmol/ L) (p < 0.05). CSF neopterin concentrations in HAM/TSP patients were higher than in serum samples, and higher compared to carriers (p < 0.05). Carriers had similar serum-CSF neopterin concentrations compared to healthy participants. Variable clinical and laboratory profiles were seen in HAM/TSP patients, however our results support the neopterin measurement as a potential biomarker of disease activity. PMID:28380116

Physical analyses of compost from composting plants in Brazil.

PubMed

Barreira, L P; Philippi Junior, A; Rodrigues, M S; Tenório, J A S

2008-01-01

Nowadays the composting process has shown itself to be an alternative in the treatment of municipal solid wastes by composting plants. However, although more than 50% of the waste generated by the Brazilian population is composed of matter susceptible to organic composting, this process is, still today, insufficiently developed in Brazil, due to low compost quality and lack of investments in the sector. The objective of this work was to use physical analyses to evaluate the quality of the compost produced at 14 operative composting plants in the Sao Paulo State in Brazil. For this purpose, size distribution and total inert content tests were done. The results were analyzed by grouping the plants according to their productive processes: plants with a rotating drum, plants with shredders or mills, and plants without treatment after the sorting conveyor belt. Compost quality was analyzed considering the limits imposed by the Brazilian Legislation and the European standards for inert contents. The size distribution tests showed the influence of the machinery after the sorting conveyer on the granule sizes as well as the inert content, which contributes to the presence of materials that reduce the quality of the final product.

Characterization of an extracellular endopolygalacturonase from the saprobe Mucor ramosissimus Samutsevitsch and its action as trigger of defensive response in tropical plants.

PubMed

Marques, Maria Rita; Buckeridge, Marcos S; Braga, Marcia R; Dietrich, Sonia M C

2006-11-01

In recent years, interest in the ability of non-pathogenic microorganisms to induce resistance in plants has grown, particularly with respect to their use as environmentally safe controllers of plant disease. In this study, we investigated the capacity of Mucor ramosissimus Samutsevitsch to release pectinases able to degrade cell walls of Palicourea marcgravii St. Hil., a tropical forest native Rubiaceae on which the spores of this saprobic fungus have been found. The fungus was grown in liquid culture medium containing pectin as the sole carbon source and filtrates were analyzed for pectinase activity. An endopolygalacturonase was partially purified by ion exchange chromatography, gel filtration, and preparative isoelectrofocusing, and characterized. This enzyme was more active upon pectic substrates with a low degree of methyl esterification. The products of hydrolysis of different pectic substrates (including pectin from P. marcgravii) by the action of this endopolygalacturonase elicited to different extents the phytoalexin production in soybean cotyledons. Also, the enzyme itself and the products of its action on the pectic fraction of P. marcgravii elicited the production of defensive compounds in the leaves of the plant. These results suggest that, besides the role in recycling organic matter, saprobes may also play an important role in the induction of defensive mechanisms in wild plants by enhancing their non-specific resistance against pathogens. Furthermore, they set the stage for future studies on the role of saprobic fungi in inducing resistance of host plants to pathogens.

Partitioning of soil phosphorus among arbuscular and ectomycorrhizal trees in tropical and subtropical forests.

PubMed

Liu, Xubing; Burslem, David F R P; Taylor, Joe D; Taylor, Andy F S; Khoo, Eyen; Majalap-Lee, Noreen; Helgason, Thorunn; Johnson, David

2018-05-01

Partitioning of soil phosphorus (P) pools has been proposed as a key mechanism maintaining plant diversity, but experimental support is lacking. Here, we provided different chemical forms of P to 15 tree species with contrasting root symbiotic relationships to investigate plant P acquisition in both tropical and subtropical forests. Both ectomycorrhizal (ECM) and arbuscular mycorrhizal (AM) trees responded positively to addition of inorganic P, but strikingly, ECM trees acquired more P from a complex organic form (phytic acid). Most ECM tree species and all AM tree species also showed some capacity to take up simple organic P (monophosphate). Mycorrhizal colonisation was negatively correlated with soil extractable P concentration, suggesting that mycorrhizal fungi may regulate organic P acquisition among tree species. Our results support the hypothesis that ECM and AM plants partition soil P sources, which may play an ecologically important role in promoting species coexistence in tropical and subtropical forests. © 2018 John Wiley & Sons Ltd/CNRS.

Life history and host range of Oxydia vesulia transpeneus, an unsuitable biological control agent of Brazilian peppertree

USDA-ARS?s Scientific Manuscript database

The suitability of Oxydia vesulia (Cramer) (Lepidoptera: Geometridae) was assessed as a potential biological control agent of the invasive weed Brazilian Peppertree Schinus terebinthifolia. Larvae were collected in Brazil feeding on the plant in its native range and colonized in quarantine where lif...

Talking about Plants and People

ERIC Educational Resources Information Center

Peacock, Alan

2004-01-01

The Eden Project in Cornwall sets out to educate about the interdependence of plants and people. Its tropical and Mediterranean biomes are housed in the largest "greenhouses" in the world, which serve as a backdrop to plants that grow in the temperate zones of the world, grown in Eden's outdoor landscape. Eden has aroused worldwide…

Global warming, elevational range shifts, and lowland biotic attrition in the wet tropics.

PubMed

Colwell, Robert K; Brehm, Gunnar; Cardelús, Catherine L; Gilman, Alex C; Longino, John T

2008-10-10

Many studies suggest that global warming is driving species ranges poleward and toward higher elevations at temperate latitudes, but evidence for range shifts is scarce for the tropics, where the shallow latitudinal temperature gradient makes upslope shifts more likely than poleward shifts. Based on new data for plants and insects on an elevational transect in Costa Rica, we assess the potential for lowland biotic attrition, range-shift gaps, and mountaintop extinctions under projected warming. We conclude that tropical lowland biotas may face a level of net lowland biotic attrition without parallel at higher latitudes (where range shifts may be compensated for by species from lower latitudes) and that a high proportion of tropical species soon faces gaps between current and projected elevational ranges.

Assessing the impacts of canopy openness and flight parameters on detecting a sub-canopy tropical invasive plant using a small unmanned aerial system

NASA Astrophysics Data System (ADS)

Perroy, Ryan L.; Sullivan, Timo; Stephenson, Nathan

2017-03-01

Small unmanned aerial systems (sUAS) have great potential to facilitate the early detection and management of invasive plants. Here we show how very high-resolution optical imagery, collected from small consumer-grade multirotor UAS platform at altitudes of 30-120 m above ground level (agl), can be used to detect individual miconia (Miconia calvescens) plants in a highly invaded tropical rainforest environment on the island of Hawai'i. The central aim of this research was to determine how overstory vegetation cover, imagery resolution, and camera look-angle impact the aerial detection of known individual miconia plants. For our finest resolution imagery (1.37 cm ground sampling distance collected at 30 m agl), we obtained a 100% detection rate for sub-canopy plants with above-crown openness values >40% and a 69% detection rate for those with >20% openness. We were unable to detect any plants with <10% above crown openness. Detection rates progressively declined with coarser spatial resolution imagery, ending in a 0% detection rate for the 120 m agl flights (ground sampling distance of 5.31 cm). The addition of forward-looking oblique imagery improved detection rates for plants below overstory vegetation, though this effect decreased with increasing flight altitude. While dense overstory canopy cover, limited flight times, and visual line of sight regulations present formidable obstacles for detecting miconia and other invasive plant species, we show that sUAS platforms carrying optical sensors can be an effective component of an integrated management plan within challenging subcanopy forest environments.

Military tropical medicine.

PubMed

Bailey, M S; Ellis, C J

2009-03-01

Tropical diseases remain a significant threat to deployed military personnel as demonstrated by recent outbreaks amongst troops in Sierra Leone, Iraq and Afghanistan. Five cases are presented from military deployments in tropical or sub-tropical areas, which illustrate important diseases and diagnostic principles for military physicians.

Phenotypic and molecular fingerprinting of fast growing rhizobia of field-grown pigeonpea from the eastern edge of the Brazilian Pantanal.

PubMed

Costa, F M; Schiavo, J A; Brasil, M S; Leite, J; Xavier, G R; Fernandes, P I

2014-01-21

The aim of this study was to evaluate the diversity of rhizobial isolates obtained from root nodules of pigeonpea plants grown at the eastern edge of the Brazilian Pantanal. The bacterial isolates were isolated from root nodules from field-growing pigeonpea grown in two rural settlements of the Aquidauana municipality. The bacterial isolates were characterized phenotypically by means of cultural characterization, intrinsic antibiotic resistance (IAR), salt and high incubation temperature tolerance, and amylolytic and cellulolytic activities. The molecular characterization of the bacterial isolates was carried out using amplified ribosomal DNA restriction analysis (ARDRA) and Box-polymerase chain reaction (PCR) techniques. In addition, the symbiotic performance of selected rhizobial isolates was evaluated in a greenhouse experiment using sterile substrate. The phenotypic characterization revealed that the bacterial strains obtained from pigeonpea root nodules presented characteristics that are uncommon among rhizobial isolates, indicating the presence of new species nodulating the pigeonpea plants in the Brazilian Pantanal. The molecular fingerprinting of these bacterial isolates also showed a highly diverse collection, with both techniques revealing less than 25% similarity among bacterial isolates. The evaluation of symbiotic performance also indicated the presence of microorganisms with high potential to increase the growth and nitrogen content at the shoots of pigeonpea plants. The results obtained in this study indicate the presence of a highly diversified rhizobial community nodulating the pigeonpea at the eastern edge of the Brazilian Pantanal.

Links between tree species, symbiotic fungal diversity and ecosystem functioning in simplified tropical ecosystems.

PubMed

Lovelock, Catherine E; Ewel, John J

2005-07-01

We studied the relationships among plant and arbuscular mycorrhizal (AM) fungal diversity, and their effects on ecosystem function, in a series of replicate tropical forestry plots in the La Selva Biological Station, Costa Rica. Forestry plots were 12 yr old and were either monocultures of three tree species, or polycultures of the tree species with two additional understory species. Relationships among the AM fungal spore community, host species, plant community diversity and ecosystem phosphorus-use efficiency (PUE) and net primary productivity (NPP) were assessed. Analysis of the relative abundance of AM fungal spores found that host tree species had a significant effect on the AM fungal community, as did host plant community diversity (monocultures vs polycultures). The Shannon diversity index of the AM fungal spore community differed significantly among the three host tree species, but was not significantly different between monoculture and polyculture plots. Over all the plots, significant positive relationships were found between AM fungal diversity and ecosystem NPP, and between AM fungal community evenness and PUE. Relative abundance of two of the dominant AM fungal species also showed significant correlations with NPP and PUE. We conclude that the AM fungal community composition in tropical forests is sensitive to host species, and provide evidence supporting the hypothesis that the diversity of AM fungi in tropical forests and ecosystem NPP covaries.

Structure and genetic diversity of natural Brazilian pepper populations (Schinus terebinthifolius Raddi).

PubMed

Álvares-Carvalho, S V; Duarte, J F; Santos, T C; Santos, R M; Silva-Mann, R; Carvalho, D

2016-06-17

In the face of a possible loss of genetic diversity in plants due the environmental changes, actions to ensure the genetic variability are an urgent necessity. The extraction of Brazilian pepper fruits is a cause of concern because it results in the lack of seeds in soil, hindering its distribution in space and time. It is important to address this concern and explore the species, used by riparian communities and agro-factories without considering the need for keeping the seeds for natural seed banks and for species sustainability. The objective of this study was to evaluate the structure and the genetic diversity in natural Brazilian pepper populations (Schinus terebinthifolius Raddi). Twenty-two alleles in 223 individuals were identified from eight forest remnants located in the states of Minas Gerais, Espírito Santo, and Sergipe. All populations presented loci in Hardy-Weinberg equilibrium deviation. Four populations presented six combinations of loci in linkage disequilibrium. Six exclusive alleles were detected in four populations. Analysis of molecular variance showed the absence of diversity between regions and that between the populations (GST) was 41%. Genetic diversity was structured in seven clusters (ΔK7). Brazilian pepper populations were not structured in a pattern of isolation by distance and present genetic bottleneck. The populations São Mateus, Canastra, Barbacena, and Ilha das Flores were identified as management units and may support conservation projects, ecological restoration and in implementation of management plans for Brazilian pepper in the State of Sergipe.

Competition from below for light and nutrients shifts productivity among tropical species.

PubMed

Ewel, John J; Mazzarino, María Julia

2008-12-02

Chance events such as seed dispersal determine the potential composition of plant communities, but the eventual assemblage is determined in large part by subsequent interactions among species. Postcolonization sorting also affects the ultimate composition of communities assembled by people for restoration, horticulture, or conservation. Thus, knowledge of the mechanisms controlling interspecific interactions in plant communities is important for explaining patterns observed in nature and predicting success or failure of utilitarian combinations. Relationships among species, especially those from studies of biological diversity and ecosystem functioning, are largely based on studies of short-lived, temperate-zone plants. Extrapolation to perennial plants in the humid tropics is risky because functional relationships among large-stature species change with time. Shifts in competitive relationships among 3 life forms--trees, palms, and perennial herbs--occurred during 13 yr in experimental tropical ecosystems. In 2 cases the novel competitive mechanism responsible for the shift was reduction in crown volume, and therefore light-capturing capability, of overtopping deciduous trees by intrusive growth from below a palm. In a third case, complementary resource use developed between 2 evergreen life forms (overstory tree and palm), probably because of differential nutrient acquisition. Species-level traits and adequate time for shifts in interspecific relationships to emerge are crucial for predicting community trajectories.

Arbuscular and Ectomycorrhizal Fungi Associated with the Invasive Brazilian Pepper Tree (Schinus terebinthifolius) and Two Native Plants in South Florida

PubMed Central

Dawkins, Karim; Esiobu, Nwadiuto

2017-01-01

The potential role of soil fungi in the invasion of the Brazilian pepper tree (Schinus terebinthifolius—BP) in Florida is not known; although the low biotic resistance of Florida soils is often invoked to explain the prevalence of many invasive species. To gain an initial insight into BP's mycorrhizal associations, this study examined the rhizobiome of BP and two native plants (Hamelia patens and Bidens alba) across six locations. Arbuscular mycorrhizal fungi (AMF) associated with the roots of the target plants and bulk soil was characterized by spore morphotyping. Sequence analysis of metagenomic DNA from lateral roots/rhizosphere of BP (n = 52) and a native shrub H. patens (n = 37) on the same parcel yielded other fungal associates. Overall, the total population of AMF associated with BP was about two folds greater than that of the two native plants (p = 0.0001) growing on the same site. The dominant AMF under Schinus were members of the common Glomus and Rhizophagus spp. By contrast, the most prevalent AMF in the bulk soil and rhizosphere of the two Florida native plants, Acaulospora spp (29%) was sharply diminished (9%) under BP rhizosphere. Analysis of the ITS2 sequences also showed that Schinus rhizosphere had a high relative abundance of ectomycorrhizal fungi (76.5%) compared to the native H. patens (2.6%), with the species Lactifluus hygrophoroides (Basidiomycota) being the most prevalent at 61.5% (p < 0.05). Unlike the native plants where pathogenic fungi like Phyllosticta sp., Phoma sp., and Neofusicoccum andium were present (8.1% for H. patens), only one potentially pathogenic fungal taxon was detected (3.9%) under BP. The striking disparity in the relative abundance of AMF and other fungal types between BP and the native species is quite significant. Fungal symbionts could aide plant invasion via resource-use efficiency and other poorly defined mechanisms of protection from pathogens in their invaded range. This report exposes a potentially

A spacing trial in tropical ash ... an interim report

Treesearch

Robert E. Burgan

1971-01-01

The optimum interval at which to plant tropical ash (Fraxinus uhdei) is being studied on the Waiakea Forest Reserve, island of Hawaii. Four spacing intervals are being tried: 6,8, 10, and 12 feet. Measurements of trial plots in 1969-8 years after plots were set up-suggest that (a) interval had not affected survival rate; (b) spacing had not affected...

Impact of livestock on a mosquito community (Diptera: Culicidae) in a Brazilian tropical dry forest.

PubMed

Santos, Cleandson Ferreira; Borges, Magno

2015-01-01

This study evaluated the effects of cattle removal on the Culicidae mosquito community structure in a tropical dry forest in Brazil. Culicidae were collected during dry and wet seasons in cattle presence and absence between August 2008 and October 2010 and assessed using multivariate statistical models. Cattle removal did not significantly alter Culicidae species richness and abundance. However, alterations were noted in Culicidae community composition. This is the first study to evaluate the impact of cattle removal on Culicidae community structure in Brazil and demonstrates the importance of assessing ecological parameters such as community species composition.

Evolution and Biogeography of the Slipper Orchids: Eocene Vicariance of the Conduplicate Genera in the Old and New World Tropics

PubMed Central

Guo, Yan-Yan; Luo, Yi-Bo; Liu, Zhong-Jian; Wang, Xiao-Quan

2012-01-01

Intercontinental disjunctions between tropical regions, which harbor two-thirds of the flowering plants, have drawn great interest from biologists and biogeographers. Most previous studies on these distribution patterns focused on woody plants, and paid little attention to herbs. The Orchidaceae is one of the largest families of angiosperms, with a herbaceous habit and a high species diversity in the Tropics. Here we investigate the evolutionary and biogeographical history of the slipper orchids, which represents a monophyletic subfamily (Cypripedioideae) of the orchid family and comprises five genera that are disjunctly distributed in tropical to temperate regions. A relatively well-resolved and highly supported phylogeny of slipper orchids was reconstructed based on sequence analyses of six maternally inherited chloroplast and two low-copy nuclear genes (LFY and ACO). We found that the genus Cypripedium with a wide distribution in the northern temperate and subtropical zones diverged first, followed by Selenipedium endemic to South America, and finally conduplicate-leaved genera in the Tropics. Mexipedium and Phragmipedium from the neotropics are most closely related, and form a clade sister to Paphiopedilum from tropical Asia. According to molecular clock estimates, the genus Selenipedium originated in Palaeocene, while the most recent common ancestor of conduplicate-leaved slipper orchids could be dated back to the Eocene. Ancestral area reconstruction indicates that vicariance is responsible for the disjunct distribution of conduplicate slipper orchids in palaeotropical and neotropical regions. Our study sheds some light on mechanisms underlying generic and species diversification in the orchid family and tropical disjunctions of herbaceous plant groups. In addition, we suggest that the biogeographical study should sample both regional endemics and their widespread relatives. PMID:22685605

Evolution and biogeography of the slipper orchids: Eocene vicariance of the conduplicate genera in the Old and New World Tropics.

PubMed

Guo, Yan-Yan; Luo, Yi-Bo; Liu, Zhong-Jian; Wang, Xiao-Quan

2012-01-01

Intercontinental disjunctions between tropical regions, which harbor two-thirds of the flowering plants, have drawn great interest from biologists and biogeographers. Most previous studies on these distribution patterns focused on woody plants, and paid little attention to herbs. The Orchidaceae is one of the largest families of angiosperms, with a herbaceous habit and a high species diversity in the Tropics. Here we investigate the evolutionary and biogeographical history of the slipper orchids, which represents a monophyletic subfamily (Cypripedioideae) of the orchid family and comprises five genera that are disjunctly distributed in tropical to temperate regions. A relatively well-resolved and highly supported phylogeny of slipper orchids was reconstructed based on sequence analyses of six maternally inherited chloroplast and two low-copy nuclear genes (LFY and ACO). We found that the genus Cypripedium with a wide distribution in the northern temperate and subtropical zones diverged first, followed by Selenipedium endemic to South America, and finally conduplicate-leaved genera in the Tropics. Mexipedium and Phragmipedium from the neotropics are most closely related, and form a clade sister to Paphiopedilum from tropical Asia. According to molecular clock estimates, the genus Selenipedium originated in Palaeocene, while the most recent common ancestor of conduplicate-leaved slipper orchids could be dated back to the Eocene. Ancestral area reconstruction indicates that vicariance is responsible for the disjunct distribution of conduplicate slipper orchids in palaeotropical and neotropical regions. Our study sheds some light on mechanisms underlying generic and species diversification in the orchid family and tropical disjunctions of herbaceous plant groups. In addition, we suggest that the biogeographical study should sample both regional endemics and their widespread relatives.

Tropical sprue

MedlinePlus

... than avoiding living in or traveling to tropical climates, there is no known prevention for tropical sprue. ... Clinical Professor of Medicine, The George Washington University School of Medicine, Washington, DC. Also reviewed by David ...

Experimental defaunation of terrestrial mammalian herbivores alters tropical rainforest understorey diversity