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Sample records for alien tree species

  1. ALIEN SPECIES: THEIR ROLE IN AMPHIBIAN POPULATION DECLINES AND RESTORATION

    EPA Science Inventory

    Alien species (also referred to as exotic, invasive, introduced, or normative species) have been implicated as causal agents in population declines of many amphibian species. Herein, we evaluate the relative contributions of alien species and other factors in adversely affecting ...

  2. Index of Alien Impact: A method for evaluating potential ecological impact of alien plant species

    EPA Science Inventory

    Alien plant species are stressors to ecosystems and indicators of reduced ecosystem integrity. The magnitude of the stress reflects not only the quantity of aliens present, but also the quality of their interactions with native ecosystems. We develop an Index of Alien Impact (IAI...

  3. Species integrity in trees.

    PubMed

    Ortiz-Barrientos, Daniel; Baack, Eric J

    2014-09-01

    From California sequoia, to Australian eucalyptus, to the outstanding diversity of Amazonian forests, trees are fundamental to many processes in ecology and evolution. Trees define the communities that they inhabit, are host to a multiplicity of other organisms and can determine the ecological dynamics of other plants and animals. Trees are also at the heart of major patterns of biodiversity such as the latitudinal gradient of species diversity and thus are important systems for studying the origin of new plant species. Although the role of trees in community assembly and ecological succession is partially understood, the origin of tree diversity remains largely opaque. For instance, the relative importance of differing habitats and phenologies as barriers to hybridization between closely related species is still largely uncharacterized in trees. Consequently, we know very little about the origin of trees species and their integrity. Similarly, studies on the interplay between speciation and tree community assembly are in their infancy and so are studies on how processes like forest maturation modifies the context in which reproductive isolation evolves. In this issue of Molecular Ecology, Lindtke et al. (2014) and Lagache et al. (2014) overcome some traditional difficulties in studying mating systems and sexual isolation in the iconic oaks and poplars, providing novel insights about the integrity of tree species and on how ecology leads to variation in selection on reproductive isolation over time and space. PMID:25155715

  4. Alien species as a driver of recent extinctions.

    PubMed

    Bellard, Céline; Cassey, Phillip; Blackburn, Tim M

    2016-02-01

    We assessed the prevalence of alien species as a driver of recent extinctions in five major taxa (plants, amphibians, reptiles, birds and mammals), using data from the IUCN Red List. Our results show that alien species are the second most common threat associated with species that have gone completely extinct from these taxa since AD 1500. Aliens are the most common threat associated with extinctions in three of the five taxa analysed, and for vertebrate extinctions overall. PMID:26888913

  5. Widespread plant species: natives vs. aliens in our changing world

    USGS Publications Warehouse

    Stohlgren, Thomas J.; Pyšek, Petr; Kartesz, John; Nishino, Misako; Pauchard, Aníbal; Winter, Marten; Pino, Joan; Richardson, David M.; Wilson, John R.U.; Murray, Brad R.; Phillips, Megan L.; Ming-yang, Li; Celesti-Grapow, Laura; Font, Xavier

    2011-01-01

    Estimates of the level of invasion for a region are traditionally based on relative numbers of native and alien species. However, alien species differ dramatically in the size of their invasive ranges. Here we present the first study to quantify the level of invasion for several regions of the world in terms of the most widely distributed plant species (natives vs. aliens). Aliens accounted for 51.3% of the 120 most widely distributed plant species in North America, 43.3% in New South Wales (Australia), 34.2% in Chile, 29.7% in Argentina, and 22.5% in the Republic of South Africa. However, Europe had only 1% of alien species among the most widespread species of the flora. Across regions, alien species relative to native species were either as well-distributed (10 comparisons) or more widely distributed (5 comparisons). These striking patterns highlight the profound contribution that widespread invasive alien plants make to floristic dominance patterns across different regions. Many of the most widespread species are alien plants, and, in particular, Europe and Asia appear as major contributors to the homogenization of the floras in the Americas. We recommend that spatial extent of invasion should be explicitly incorporated in assessments of invasibility, globalization, and risk assessments.

  6. Widespread plant species: Natives versus aliens in our changing world

    USGS Publications Warehouse

    Stohlgren, T.J.; Pysek, P.; Kartesz, J.; Nishino, M.; Pauchard, A.; Winter, M.; Pino, J.; Richardson, D.M.; Wilson, J.R.U.; Murray, B.R.; Phillips, M.L.; Ming-yang, L.; Celesti-Grapow, L.; Font, X.

    2011-01-01

    Estimates of the level of invasion for a region are traditionally based on relative numbers of native and alien species. However, alien species differ dramatically in the size of their invasive ranges. Here we present the first study to quantify the level of invasion for several regions of the world in terms of the most widely distributed plant species (natives vs. aliens). Aliens accounted for 51.3% of the 120 most widely distributed plant species in North America, 43.3% in New South Wales (Australia), 34.2% in Chile, 29.7% in Argentina, and 22.5% in the Republic of South Africa. However, Europe had only 1% of alien species among the most widespread species of the flora. Across regions, alien species relative to native species were either as well-distributed (10 comparisons) or more widely distributed (5 comparisons). These striking patterns highlight the profound contribution that widespread invasive alien plants make to floristic dominance patterns across different regions. Many of the most widespread species are alien plants, and, in particular, Europe and Asia appear as major contributors to the homogenization of the floras in the Americas. We recommend that spatial extent of invasion should be explicitly incorporated in assessments of invasibility, globalization, and risk assessments. ?? 2011 Springer Science+Business Media B.V.

  7. Sentinel Trees as a Tool to Forecast Invasions of Alien Plant Pathogens

    PubMed Central

    Vettraino, AnnaMaria; Roques, Alain; Yart, Annie; Fan, Jian-ting; Sun, Jiang-hua; Vannini, Andrea

    2015-01-01

    Recent disease outbreaks caused by alien invasive pathogens into European forests posed a serious threat to forest sustainability with relevant environmental and economic effects. Many of the alien tree pathogens recently introduced into Europe were not previously included on any quarantine lists, thus they were not subject to phytosanitary inspections. The identification and description of alien fungi potentially pathogenic to native European flora before their introduction in Europe, is a paramount need in order to limit the risk of invasion and the impact to forest ecosystems. To determine the potential invasive fungi, a sentinel trees plot was established in Fuyang, China, using healthy seedlings of European tree species including Quercus petreae, Q. suber, and Q. ilex. The fungal assemblage associated with symptomatic specimens was studied using the tag-encoded 454 pyrosequencing of the nuclear ribosomal internal transcribed spacer-1 (ITS 1). Taxa with probable Asiatic origin were identified and included plant pathogenic genera. These results indicate that sentinel plants may be a strategic tool to improve the prevention of bioinvasions. PMID:25826684

  8. Index of Alien Impact: A Method for Evaluating Potential Ecological Impact of Alien Plant Species

    NASA Astrophysics Data System (ADS)

    Magee, Teresa K.; Ringold, Paul L.; Bollman, Michael A.; Ernst, Ted L.

    2010-04-01

    Alien plant species are stressors to ecosystems and indicators of reduced ecosystem integrity. The magnitude of the stress reflects not only the quantity of aliens present, but also the quality of their interactions with native ecosystems. We develop an Index of Alien Impact ( IAI) to estimate the collective ecological impact of in situ alien species. IAI summarizes the frequency of occurrence and potential ecological impact ( Invasiveness-Impact Score ( I i )) of individual alien species for all aliens present in a particular location or community type. A component metric, I i , is based on ecological species traits (life history, ecological amplitude, and ability to alter ecosystem processes) that reflect mechanisms, which can increase impact to ecosystem structure and function. While I i is less complex than some other multi-metric rankings of alien impact, it compares well to these metrics and to qualitative judgments. IAI can be adapted for different ecological settings by modifying the set of species traits incorporated in I i to reflect properties likely to breach biotic and abiotic barriers or alter ecosystem function in a particular region or community type of interest. To demonstrate our approach, we created versions of IAI and I i , applicable to the diverse streamside vegetation of a river basin (19,631 km2) spanning low-elevation arid to mesic montane habitats in eastern Oregon, USA. In this demonstration effort, we (1) evaluate relationships of IAI to metrics describing invasion level, and (2) illustrate the potential utility of IAI for prioritizing alien species management activities and informing restoration goals.

  9. Impact of an Alien Invasive Shrub on Ecology of Native and Alien Invasive Mosquito Species (Diptera: Culicidae).

    PubMed

    Muturi, Ephantus J; Gardner, Allison M; Bara, Jeffrey J

    2015-10-01

    We examined how leaf litter of alien invasive honeysuckle (Lonicera maackii Rupr.) either alone or in combination with leaf litter of one of two native tree species, sugar maple (Acer saccharum Marshall) and northern red oak (Quercus rubra L.), affects the ecology of Culex restuans Theobald, Ochlerotatus triseriatus Say, and Ochlerotatus japonicus Theobald. Experimental mesocosms containing single species litter or a mixture of honeysuckle and one of two native tree species litter were established at South Farms and Trelease Woods study sites in Urbana, IL, and examined for their effect on 1) oviposition site selection by the three mosquito species, and 2) adult production and body size of Oc. triseriatus and Oc. japonicus. There were no significant effects of study site and leaf treatment on Oc. japonicus and Oc. triseriatus oviposition preference and adult production. In contrast, significantly more Cx. restuans eggs rafts were collected at South Farms relative to Trelease Woods and in honeysuckle litter relative to native tree species litter. Significantly larger adult females of Oc. japonicus and Oc. triseriatus were collected at South Farms relative to Trelease Woods and in honeysuckle litter relative to native tree species litter. Combining honeysuckle litter with native tree species litter had additive effects on Cx. restuans oviposition preference and Oc. japonicus and Oc. triseriatus body size, with the exception of honeysuckle and northern red oak litter combination, which had antagonistic effects on Oc. triseriatus body size. We conclude that input of honeysuckle litter into container aquatic habitats may alter the life history traits of vector mosquito species. PMID:26314023

  10. Alien molluscan species established along the Italian shores: an update, with discussions on some Mediterranean "alien species" categories.

    PubMed

    Crocetta, Fabio; Macali, Armando; Furfaro, Giulia; Cooke, Samantha; Guido Villani; Valdés, Angel

    2013-01-01

    The state of knowledge of the alien marine Mollusca in Italy is reviewed and updated. Littorina saxatilis (Olivi, 1792), Polycera hedgpethi Er. Marcus, 1964 and Haminoea japonica Pilsbry, 1895are here considered as established on the basis of published and unpublished data, and recent records of the latter considerably expand its known Mediterranean range to the Tyrrhenian Sea. COI sequences obtained indicate that a comprehensive survey of additional European localities is needed to elucidate the dispersal pathways of Haminoea japonica.Recent records and interpretation of several molluscan taxa as alien are discussed both in light of new Mediterranean (published and unpublished) records and of four categories previously excluded from alien species lists. Within this framework, ten taxa are no longer considered as alien species, or their records from Italy are refuted. Furthermore, Trochocochlea castriotae Bellini, 1903 is considered a new synonym for Gibbula albida (Gmelin, 1791). Data provided here leave unchanged as 35 the number of alien molluscan taxa recorded from Italy as well as the percentage of the most plausible vectors of introduction, but raise to 22 the number of established species along the Italian shores during the 2005-2010 period, and backdate to 1792 the first introduction of an alien molluscan species (Littorina saxatilis) to the Italian shores. PMID:23794825

  11. RELATIONSHIPS OF ALIEN PLANT SPECIES ABUNDANCE TO RIPARIAN VEGETATION, ENVIRONMENT, AND DISTURBANCE

    EPA Science Inventory

    Riparian ecosystems are often invaded by alien species. We evaluated vegetation, environment, and disturbance conditions and their interrelationships with alien species abundance along reaches of 29 streams in eastern Oregon, USA. Using flexible-BETA clustering, indicator species...

  12. Alien species in a warmer world: risks and opportunities.

    PubMed

    Walther, Gian-Reto; Roques, Alain; Hulme, Philip E; Sykes, Martin T; Pysek, Petr; Kühn, Ingolf; Zobel, Martin; Bacher, Sven; Botta-Dukát, Zoltán; Bugmann, Harald; Czúcz, Bálint; Dauber, Jens; Hickler, Thomas; Jarosík, Vojtech; Kenis, Marc; Klotz, Stefan; Minchin, Dan; Moora, Mari; Nentwig, Wolfgang; Ott, Jürgen; Panov, Vadim E; Reineking, Björn; Robinet, Christelle; Semenchenko, Vitaliy; Solarz, Wojciech; Thuiller, Wilfried; Vilà, Montserrat; Vohland, Katrin; Settele, Josef

    2009-12-01

    Climate change and biological invasions are key processes affecting global biodiversity, yet their effects have usually been considered separately. Here, we emphasise that global warming has enabled alien species to expand into regions in which they previously could not survive and reproduce. Based on a review of climate-mediated biological invasions of plants, invertebrates, fishes and birds, we discuss the ways in which climate change influences biological invasions. We emphasise the role of alien species in a more dynamic context of shifting species' ranges and changing communities. Under these circumstances, management practices regarding the occurrence of 'new' species could range from complete eradication to tolerance and even consideration of the 'new' species as an enrichment of local biodiversity and key elements to maintain ecosystem services. PMID:19712994

  13. Impacts of Alien Tree Invasion on Evapotranspiration in Tropical Montane Cloud Forest in Hawai'i

    NASA Astrophysics Data System (ADS)

    Giambelluca, T. W.; Asner, G. P.; Martin, R. E.; Nullet, M. M.; Huang, M.; Delay, J. K.; Mudd, R. G.; Takahashi, M.

    2007-12-01

    Hawaiian tropical montane cloud forests (TMCFs) are ecologically and hydrologically valuable zones. TMCFs in Hawai'i serve as refugia for the remaining intact native terrestrial plant and animal ecosystems, and are major sources of hydrologic input to surface water and groundwater systems. Invasion of alien tree species, with obvious effects on the ecological integrity of TMCFs, also threatens to impact the hydrological services these forests provide. Much speculation has been made about the hydrological effects of replacing native forest tree species with alien trees in Hawai'i, but until now no measurements have been made to test these assertions. We established two study sites, each equipped with eddy covariance and other micrometeorological instrumentation, one within native Metrosideros polymorpha forest and the other at a site heavily invaded by Psidium cattleianum, in the cloud forest zone of Hawai'i Volcanoes National Park. We are conducting measurements of stand-level evapotranspiration, transpiration (using sapflow techniques), energy balance, throughfall, stemflow, and soil moisture at each site. Preliminary analysis of these measurements shows that the fraction of available energy used for evapotranspiration (ET Fraction) at the native site is much higher for wet canopy conditions. The ET Fraction at the native site has an annual cycle corresponding to the annual cycle in leaf area. Deviations from the annual cycle are more closely related to variations in canopy wetness than to variations in soil moisture. Overall, ET as a function of available energy is 27% higher at the invaded site than the native site. The difference in ET between the two sites is especially pronounced during dry canopy periods, during which the ET Fraction is 53% higher at the invaded site than the native site. Sapflow measurements using heat balance collars show that leaf-area-specific transpiration is much greater in invasive P. cattleianum trees than in remnant native M

  14. Alien invasive species and international trade

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Emergency control measures for invasive species often rely on use of pesticides and other destructive practices. Public concern about pesticide contamination of the ground water and the environment has lead to increased restrictions on the use of pesticides for control of many destructive invasive ...

  15. Effects of invasive alien kahili ginger (Hedychium gardnerianum) on native plant species regeneration in a Hawaiian rainforest

    USGS Publications Warehouse

    Minden, V.; Jacobi, J.D.; Porembski, S.; Boehmer, H.J.

    2010-01-01

    Questions: Does the invasive alien Hedychium gardnerianum (1) replace native understory species, (2) suppress natural regeneration of native plant species, (3) increase the invasiveness of other non-native plants and (4) are native forests are able to recover after removal of H. gardnerianum. Location: A mature rainforest in Hawai'i Volcanoes National Park on the island of Hawai'i (about 1200 m. a.s.l.; precipitation approximately 2770mm yr-1). Study sites included natural plots without effects of alien plants, ginger plots with a H. gardnerianum-domimted herb layer and cleared plots treated with herbicide to remove alien plants. Methods: Counting mature trees, saplings and seedlings of native and alien plant species. Using nonparametric H-tests to compare impact of H. gardnerianum on the structure of different sites. Results: Results confirmed the hypothesis that H. gardnerianum has negative effects on natural forest dynamics. Lower numbers of native tree seedlings and saplings were found on ginger-dominated plots. Furthermore, H. gardnerianum did not show negative effects on the invasive alien tree species Psidium cattleianum. Conclusions: This study reveals that where dominance of H. gardnerianum persists, regeneration of the forest by native species will be inhibited. Furthermore, these areas might experience invasion by P. cattleianum, resulting in displacement of native canopy species in the future, leading to a change in forest structure and loss of other species dependent on natural rainforest, such as endemic birds. However, if H. gardnerianum is removed the native Hawaiian forest is likely to regenerate and regain its natural structure. ?? 2009 International Association for Vegetation Science.

  16. Long-term ecology resolves the timing, region of origin and process of establishment for a disputed alien tree.

    PubMed

    Wilmshurst, Janet M; McGlone, Matt S; Turney, Chris S M

    2015-01-01

    Alien plants are a pervasive environmental problem, particularly on islands where they can rapidly transform unique indigenous ecosystems. However, often it is difficult to confidently determine whether a species is native or alien, especially if establishment occurred before historical records. This can present a management challenge: for example, should such taxa be eradicated or left alone until their region of origin and status are clarified? Here we show how combining palaeoecological and historical records can help resolve such dilemmas, using the tree daisy Olearia lyallii on the remote New Zealand subantarctic Auckland Islands as a case study. The status of this tree as native or introduced has remained uncertain for the 175 years since it was first discovered on the Auckland Islands, and its appropriate management is debated. Elsewhere, O. lyallii has a highly restricted distribution on small sea bird-rich islands within a 2° latitudinal band south of mainland New Zealand. Analysis of palaeoecological and historical records from the Auckland Islands suggest that O. lyallii established there c. 1807 when these islands were first exploited by European sealers. Establishment was facilitated by anthropogenic burning and clearing and its subsequent spread has been slow, limited in distribution and probably human-assisted. Olearia lyallii has succeeded mostly in highly disturbed sites which are also nutrient enriched from nesting sea birds, seals and sea spray. This marine subsidy has fuelled the rapid growth of O. lyallii and allowed this tree to be competitive against the maritime communities it has replaced. Although endemic to the New Zealand region, our evidence suggests that O. lyallii is alien to the Auckland Islands. Although such 'native' aliens can pose unique management challenges on islands, in this instance we suggest that ongoing monitoring with no control is an appropriate management action, as O. lyallii appears to pose minimal risk to

  17. Long-term ecology resolves the timing, region of origin and process of establishment for a disputed alien tree

    PubMed Central

    Wilmshurst, Janet M.; McGlone, Matt S.; Turney, Chris S.M.

    2015-01-01

    Alien plants are a pervasive environmental problem, particularly on islands where they can rapidly transform unique indigenous ecosystems. However, often it is difficult to confidently determine whether a species is native or alien, especially if establishment occurred before historical records. This can present a management challenge: for example, should such taxa be eradicated or left alone until their region of origin and status are clarified? Here we show how combining palaeoecological and historical records can help resolve such dilemmas, using the tree daisy Olearia lyallii on the remote New Zealand subantarctic Auckland Islands as a case study. The status of this tree as native or introduced has remained uncertain for the 175 years since it was first discovered on the Auckland Islands, and its appropriate management is debated. Elsewhere, O. lyallii has a highly restricted distribution on small sea bird-rich islands within a 2° latitudinal band south of mainland New Zealand. Analysis of palaeoecological and historical records from the Auckland Islands suggest that O. lyallii established there c. 1807 when these islands were first exploited by European sealers. Establishment was facilitated by anthropogenic burning and clearing and its subsequent spread has been slow, limited in distribution and probably human-assisted. Olearia lyallii has succeeded mostly in highly disturbed sites which are also nutrient enriched from nesting sea birds, seals and sea spray. This marine subsidy has fuelled the rapid growth of O. lyallii and allowed this tree to be competitive against the maritime communities it has replaced. Although endemic to the New Zealand region, our evidence suggests that O. lyallii is alien to the Auckland Islands. Although such ‘native’ aliens can pose unique management challenges on islands, in this instance we suggest that ongoing monitoring with no control is an appropriate management action, as O. lyallii appears to pose minimal risk to

  18. STRAW: Species TRee Analysis Web server

    PubMed Central

    Shaw, Timothy I.; Ruan, Zheng; Glenn, Travis C.; Liu, Liang

    2013-01-01

    The coalescent methods for species tree reconstruction are increasingly popular because they can accommodate coalescence and multilocus data sets. Herein, we present STRAW, a web server that offers workflows for reconstruction of phylogenies of species using three species tree methods—MP-EST, STAR and NJst. The input data are a collection of rooted gene trees (for STAR and MP-EST methods) or unrooted gene trees (for NJst). The output includes the estimated species tree, modified Robinson-Foulds distances between gene trees and the estimated species tree and visualization of trees to compare gene trees with the estimated species tree. The web sever is available at http://bioinformatics.publichealth.uga.edu/SpeciesTreeAnalysis/. PMID:23661681

  19. The Inference of Gene Trees with Species Trees

    PubMed Central

    Szöllősi, Gergely J.; Tannier, Eric; Daubin, Vincent; Boussau, Bastien

    2015-01-01

    This article reviews the various models that have been used to describe the relationships between gene trees and species trees. Molecular phylogeny has focused mainly on improving models for the reconstruction of gene trees based on sequence alignments. Yet, most phylogeneticists seek to reveal the history of species. Although the histories of genes and species are tightly linked, they are seldom identical, because genes duplicate, are lost or horizontally transferred, and because alleles can coexist in populations for periods that may span several speciation events. Building models describing the relationship between gene and species trees can thus improve the reconstruction of gene trees when a species tree is known, and vice versa. Several approaches have been proposed to solve the problem in one direction or the other, but in general neither gene trees nor species trees are known. Only a few studies have attempted to jointly infer gene trees and species trees. These models account for gene duplication and loss, transfer or incomplete lineage sorting. Some of them consider several types of events together, but none exists currently that considers the full repertoire of processes that generate gene trees along the species tree. Simulations as well as empirical studies on genomic data show that combining gene tree–species tree models with models of sequence evolution improves gene tree reconstruction. In turn, these better gene trees provide a more reliable basis for studying genome evolution or reconstructing ancestral chromosomes and ancestral gene sequences. We predict that gene tree–species tree methods that can deal with genomic data sets will be instrumental to advancing our understanding of genomic evolution. PMID:25070970

  20. DEVELOPMENT OF AN INDEX OF ALIEN SPECIES INVASIVENESS: AN AID TO ASSESSING RIPARIAN VEGETATION CONDITION

    EPA Science Inventory

    Many riparian areas are invaded by alien plant species that negatively affect native species composition, community dynamics and ecosystem properties. We sampled vegetation along reaches of 31 low order streams in eastern Oregon, and characterized species assemblages at patch an...

  1. Which Factors Affect the Success or Failure of Eradication Campaigns against Alien Species?

    PubMed Central

    Pluess, Therese; Jarošík, Vojtěch; Pyšek, Petr; Cannon, Ray; Pergl, Jan; Breukers, Annemarie; Bacher, Sven

    2012-01-01

    Although issues related to the management of invasive alien species are receiving increasing attention, little is known about which factors affect the likelihood of success of management measures. We applied two data mining techniques, classification trees and boosted trees, to identify factors that relate to the success of management campaigns aimed at eradicating invasive alien invertebrates, plants and plant pathogens. We assembled a dataset of 173 different eradication campaigns against 94 species worldwide, about a half of which (50.9%) were successful. Eradications in man-made habitats, greenhouses in particular, were more likely to succeed than those in (semi-)natural habitats. In man-made habitats the probability of success was generally high in Australasia, while in Europe and the Americas it was higher for local infestations that are easier to deal with, and for international campaigns that are likely to profit from cross-border cooperation. In (semi-) natural habitats, eradication campaigns were more likely to succeed for plants introduced as an ornamental and escaped from cultivation prior to invasion. Averaging out all other factors in boosted trees, pathogens, bacteria and viruses were most, and fungi the least likely to be eradicated; for plants and invertebrates the probability was intermediate. Our analysis indicates that initiating the campaign before the extent of infestation reaches the critical threshold, starting to eradicate within the first four years since the problem has been noticed, paying special attention to species introduced by the cultivation pathway, and applying sanitary measures can substantially increase the probability of eradication success. Our investigations also revealed that information on socioeconomic factors, which are often considered to be crucial for eradication success, is rarely available, and thus their relative importance cannot be evaluated. Future campaigns should carefully document socioeconomic factors to

  2. Recommendations on standardizing lists of marine alien species: Lessons from the Mediterranean Sea.

    PubMed

    Marchini, Agnese; Galil, Bella S; Occhipinti-Ambrogi, Anna

    2015-12-15

    Analyses of marine alien species based on national/regional datasets are of paramount importance for the success of regulation on the prevention and management of invasive alien species. Yet in the extant data systems the criteria for the inclusion of records are seldom explicit, and frequently inconsistent in their definitions, spatial and temporal frames and comprehensiveness. Agreed-upon uniform guiding principles, based on solid and transparent scientific criteria, are therefore required in order to provide policy makers with validated and comparable data. Following a meta-analysis on the records of marine alien species in the Mediterranean Sea, we recommend a judicious approach to compiling the data. Here, three categories of uncertainty were identified: species' taxonomic identification, species' actual occurrence in the area, and its status as an alien. In proposing guiding principles to standardize such datasets, we aim to encourage discourse on logical, standardized and transparent criteria to substantiate records of alien species. PMID:26471066

  3. Coalescent Histories for Lodgepole Species Trees.

    PubMed

    Disanto, Filippo; Rosenberg, Noah A

    2015-10-01

    Coalescent histories are combinatorial structures that describe for a given gene tree and species tree the possible lists of branches of the species tree on which the gene tree coalescences take place. Properties of the number of coalescent histories for gene trees and species trees affect a variety of probabilistic calculations in mathematical phylogenetics. Exact and asymptotic evaluations of the number of coalescent histories, however, are known only in a limited number of cases. Here we introduce a particular family of species trees, the lodgepole species trees (λn)n ≥ 0, in which tree λn has m = 2n+1 taxa. We determine the number of coalescent histories for the lodgepole species trees, in the case that the gene tree matches the species tree, showing that this number grows with m!! in the number of taxa m. This computation demonstrates the existence of tree families in which the growth in the number of coalescent histories is faster than exponential. Further, it provides a substantial improvement on the lower bound for the ratio of the largest number of matching coalescent histories to the smallest number of matching coalescent histories for trees with m taxa, increasing a previous bound of [Formula: see text] to [Formula: see text]. We discuss the implications of our enumerative results for phylogenetic computations. PMID:25973633

  4. Canopy and knowledge gaps when invasive alien insects remove foundation species

    PubMed Central

    Marler, Thomas E.; Lawrence, John H.

    2013-01-01

    The armored scale Aulacaspis yasumatsui invaded the northern range of the cycad Cycas micronesica in 2003, and epidemic tree mortality ensued due to a lack of natural enemies of the insect. We quantified cycad demographic responses to the invasion, but the ecological responses to the selective removal of this foundation species have not been addressed. We use this case to highlight information gaps in our understanding of how alien invasive phytophagous insects force cascading adverse ecosystem changes. The mechanistic role of unique canopy gaps, oceanic island examples and threatened foundation species with distinctive traits are three issues that deserve research efforts in a quest to understand this facet of ecosystem change occurring across multiple settings globally. PMID:23847712

  5. Exact solutions for species tree inference from discordant gene trees.

    PubMed

    Chang, Wen-Chieh; Górecki, Paweł; Eulenstein, Oliver

    2013-10-01

    Phylogenetic analysis has to overcome the grant challenge of inferring accurate species trees from evolutionary histories of gene families (gene trees) that are discordant with the species tree along whose branches they have evolved. Two well studied approaches to cope with this challenge are to solve either biologically informed gene tree parsimony (GTP) problems under gene duplication, gene loss, and deep coalescence, or the classic RF supertree problem that does not rely on any biological model. Despite the potential of these problems to infer credible species trees, they are NP-hard. Therefore, these problems are addressed by heuristics that typically lack any provable accuracy and precision. We describe fast dynamic programming algorithms that solve the GTP problems and the RF supertree problem exactly, and demonstrate that our algorithms can solve instances with data sets consisting of as many as 22 taxa. Extensions of our algorithms can also report the number of all optimal species trees, as well as the trees themselves. To better asses the quality of the resulting species trees that best fit the given gene trees, we also compute the worst case species trees, their numbers, and optimization score for each of the computational problems. Finally, we demonstrate the performance of our exact algorithms using empirical and simulated data sets, and analyze the quality of heuristic solutions for the studied problems by contrasting them with our exact solutions. PMID:24131054

  6. Essential elements of online information networks on invasive alien species

    USGS Publications Warehouse

    Simpson, A.; Sellers, E.; Grosse, A.; Xie, Y.

    2006-01-01

    In order to be effective, information must be placed in the proper context and organized in a manner that is logical and (preferably) standardized. Recently, invasive alien species (IAS) scientists have begun to create online networks to share their information concerning IAS prevention and control. At a special networking session at the Beijing International Symposium on Biological Invasions, an online Eastern Asia-North American IAS Information Network (EA-NA Network) was proposed. To prepare for the development of this network, and to provide models for other regional collaborations, we compare four examples of global, regional, and national online IAS information networks: the Global Invasive Species Information Network, the Invasives Information Network of the Inter-American Biodiversity Information Network, the Chinese Species Information System, and the Invasive Species Information Node of the US National Biological Information Infrastructure. We conclude that IAS networks require a common goal, dedicated leaders, effective communication, and broad endorsement, in order to obtain sustainable, long-term funding and long-term stability. They need to start small, use the experience of other networks, partner with others, and showcase benefits. Global integration and synergy among invasive species networks will succeed with contributions from both the top-down and the bottom-up. ?? 2006 Springer.

  7. Origin matters: diversity affects the performance of alien invasive species but not of native species.

    PubMed

    Sun, Yan; Müller-Schärer, Heinz; Maron, John L; Schaffner, Urs

    2015-06-01

    At local scales, it has often been found that invasibility decreases with increasing resident plant diversity. However, whether resident community diversity similarly resists invasion by alien versus native species is seldom studied. We examined this issue by invading constructed native plant assemblages that varied in species and functional richness with invasive alien or native Asteraceae species. Assemblages were also invaded with spotted knapweed, Centaurea stoebe, a native European aster that has been previously used in diversity-invasibility experiments in North America. We also conducted a field survey to explore the generality of the patterns generated from our experimental study. Both experimental and observational work revealed that increasing diversity reduced the performance of alien but not native invaders. Centaurea stoebe invading its native community performed poorly regardless of resident diversity, whereas in a parallel, previously published study conducted in North America, C. stoebe easily invaded low-diversity but not high-diversity assemblages. Our results suggest that diversity is an attribute of resident communities that makes them more or less susceptible to invasion by novel invasive alien but not native plant species. PMID:25996858

  8. Impacts of invading alien plant species on water flows at stand and catchment scales.

    PubMed

    Le Maitre, D C; Gush, M B; Dzikiti, S

    2015-01-01

    There have been many studies of the diverse impacts of invasions by alien plants but few have assessed impacts on water resources. We reviewed the information on the impacts of invasions on surface runoff and groundwater resources at stand to catchment scales and covering a full annual cycle. Most of the research is South African so the emphasis is on South Africa's major invaders with data from commercial forest plantations where relevant. Catchment studies worldwide have shown that changes in vegetation structure and the physiology of the dominant plant species result in changes in surface runoff and groundwater discharge, whether they involve native or alien plant species. Where there is little change in vegetation structure [e.g. leaf area (index), height, rooting depth and seasonality] the effects of invasions generally are small or undetectable. In South Africa, the most important woody invaders typically are taller and deeper rooted than the native species. The impacts of changes in evaporation (and thus runoff) in dryland settings are constrained by water availability to the plants and, thus, by rainfall. Where the dryland invaders are evergreen and the native vegetation (grass) is seasonal, the increases can reach 300-400 mm/year. Where the native vegetation is evergreen (shrublands) the increases are ∼200-300 mm/year. Where water availability is greater (riparian settings or shallow water tables), invading tree water-use can reach 1.5-2.0 times that of the same species in a dryland setting. So, riparian invasions have a much greater impact per unit area invaded than dryland invasions. The available data are scattered and incomplete, and there are many gaps and issues that must be addressed before a thorough understanding of the impacts at the site scale can be gained and used in extrapolating to watershed scales, and in converting changes in flows to water supply system yields. PMID:25935861

  9. Impacts of invading alien plant species on water flows at stand and catchment scales

    PubMed Central

    Le Maitre, D. C.; Gush, M. B.; Dzikiti, S.

    2015-01-01

    There have been many studies of the diverse impacts of invasions by alien plants but few have assessed impacts on water resources. We reviewed the information on the impacts of invasions on surface runoff and groundwater resources at stand to catchment scales and covering a full annual cycle. Most of the research is South African so the emphasis is on South Africa's major invaders with data from commercial forest plantations where relevant. Catchment studies worldwide have shown that changes in vegetation structure and the physiology of the dominant plant species result in changes in surface runoff and groundwater discharge, whether they involve native or alien plant species. Where there is little change in vegetation structure [e.g. leaf area (index), height, rooting depth and seasonality] the effects of invasions generally are small or undetectable. In South Africa, the most important woody invaders typically are taller and deeper rooted than the native species. The impacts of changes in evaporation (and thus runoff) in dryland settings are constrained by water availability to the plants and, thus, by rainfall. Where the dryland invaders are evergreen and the native vegetation (grass) is seasonal, the increases can reach 300–400 mm/year. Where the native vegetation is evergreen (shrublands) the increases are ∼200–300 mm/year. Where water availability is greater (riparian settings or shallow water tables), invading tree water-use can reach 1.5–2.0 times that of the same species in a dryland setting. So, riparian invasions have a much greater impact per unit area invaded than dryland invasions. The available data are scattered and incomplete, and there are many gaps and issues that must be addressed before a thorough understanding of the impacts at the site scale can be gained and used in extrapolating to watershed scales, and in converting changes in flows to water supply system yields. PMID:25935861

  10. Invasion trajectory of alien trees: the role of introduction pathway and planting history.

    PubMed

    Donaldson, Jason E; Hui, Cang; Richardson, David M; Robertson, Mark P; Webber, Bruce L; Wilson, John R U

    2014-05-01

    Global change is driving a massive rearrangement of the world's biota. Trajectories of distributional shifts are shaped by species traits, the recipient environment and driving forces with many of the driving forces directly due to human activities. The relative importance of each in determining the distributions of introduced species is poorly understood. We consider 11 Australian Acacia species introduced to South Africa for different reasons (commercial forestry, dune stabilization and ornamentation) to determine how features of the introduction pathway have shaped their invasion history. Projections from species distribution models (SDMs) were developed to assess how the reason for introduction influences the similarity between climatic envelopes in native and alien ranges. A lattice model for an idealized invasion was developed to assess the relative contribution of intrinsic traits and introduction dynamics on the abundance and extent over the course of simulated invasions. SDMs show that alien populations of ornamental species in South Africa occupy substantially different climate space from their native ranges, whereas species introduced for forestry occupy a similar climate space in native and introduced ranges. This may partly explain the slow spread rates observed for some alien ornamental plants. Such mismatches are likely to become less pronounced with the current drive towards 'eco gardens' resulting in more introductions of ornamental species with a close climate match between native and newly introduced regions. The results from the lattice model showed that the conditions associated with the introduction pathway (especially introduction pressure) dominate early invasion dynamics. The placement of introduction foci in urban areas limited the extent and abundance of invasive populations. Features of introduction events appear to initially mask the influence of intrinsic species traits on invasions and help to explain the relative success of species

  11. Reconciliation with Non-Binary Species Trees

    PubMed Central

    Vernot, Benjamin; Stolzer, Maureen; Goldman, Aiton

    2008-01-01

    Abstract Reconciliation extracts information from the topological incongruence between gene and species trees to infer duplications and losses in the history of a gene family. The inferred duplication-loss histories provide valuable information for a broad range of biological applications, including ortholog identification, estimating gene duplication times, and rooting and correcting gene trees. While reconciliation for binary trees is a tractable and well studied problem, there are no algorithms for reconciliation with non-binary species trees. Yet a striking proportion of species trees are non-binary. For example, 64% of branch points in the NCBI taxonomy have three or more children. When applied to non-binary species trees, current algorithms overestimate the number of duplications because they cannot distinguish between duplication and incomplete lineage sorting. We present the first algorithms for reconciling binary gene trees with non-binary species trees under a duplication-loss parsimony model. Our algorithms utilize an efficient mapping from gene to species trees to infer the minimum number of duplications in O(|VG| · (kS + hS)) time, where |VG| is the number of nodes in the gene tree, hS is the height of the species tree and kS is the size of its largest polytomy. We present a dynamic programming algorithm which also minimizes the total number of losses. Although this algorithm is exponential in the size of the largest polytomy, it performs well in practice for polytomies with outdegree of 12 or less. We also present a heuristic which estimates the minimal number of losses in polynomial time. In empirical tests, this algorithm finds an optimal loss history 99% of the time. Our algorithms have been implemented in Notung, a robust, production quality, tree-fitting program, which provides a graphical user interface for exploratory analysis and also supports automated, high-throughput analysis of large data sets. PMID:18808330

  12. Modeling potential habitats for alien species Dreissena polymorpha in continental USA

    USGS Publications Warehouse

    Mingyang, Li; Yunwei, Ju; Kumar, Sunil; Stohlgren, Thomas J.

    2008-01-01

    The effective measure to minimize the damage of invasive species is to block the potential invasive species to enter into suitable areas. 1864 occurrence points with GPS coordinates and 34 environmental variables from Daymet datasets were gathered, and 4 modeling methods, i.e., Logistic Regression (LR), Classification and Regression Trees (CART), Genetic Algorithm for Rule-Set Prediction (GARP), and maximum entropy method (Maxent), were introduced to generate potential geographic distributions for invasive species Dreissena polymorpha in Continental USA. Then 3 statistical criteria of the area under the Receiver Operating Characteristic curve (AUC), Pearson correlation (COR) and Kappa value were calculated to evaluate the performance of the models, followed by analyses on major contribution variables. Results showed that in terms of the 3 statistical criteria, the prediction results of the 4 ecological niche models were either excellent or outstanding, in which Maxent outperformed the others in 3 aspects of predicting current distribution habitats, selecting major contribution factors, and quantifying the influence of environmental variables on habitats. Distance to water, elevation, frequency of precipitation and solar radiation were 4 environmental forcing factors. The method suggested in the paper can have some reference meaning for modeling habitats of alien species in China and provide a direction to prevent Mytilopsis sallei on the Chinese coast line.

  13. Species Tree Inference Using a Mixture Model.

    PubMed

    Ullah, Ikram; Parviainen, Pekka; Lagergren, Jens

    2015-09-01

    Species tree reconstruction has been a subject of substantial research due to its central role across biology and medicine. A species tree is often reconstructed using a set of gene trees or by directly using sequence data. In either of these cases, one of the main confounding phenomena is the discordance between a species tree and a gene tree due to evolutionary events such as duplications and losses. Probabilistic methods can resolve the discordance by coestimating gene trees and the species tree but this approach poses a scalability problem for larger data sets. We present MixTreEM-DLRS: A two-phase approach for reconstructing a species tree in the presence of gene duplications and losses. In the first phase, MixTreEM, a novel structural expectation maximization algorithm based on a mixture model is used to reconstruct a set of candidate species trees, given sequence data for monocopy gene families from the genomes under study. In the second phase, PrIME-DLRS, a method based on the DLRS model (Åkerborg O, Sennblad B, Arvestad L, Lagergren J. 2009. Simultaneous Bayesian gene tree reconstruction and reconciliation analysis. Proc Natl Acad Sci U S A. 106(14):5714-5719), is used for selecting the best species tree. PrIME-DLRS can handle multicopy gene families since DLRS, apart from modeling sequence evolution, models gene duplication and loss using a gene evolution model (Arvestad L, Lagergren J, Sennblad B. 2009. The gene evolution model and computing its associated probabilities. J ACM. 56(2):1-44). We evaluate MixTreEM-DLRS using synthetic and biological data, and compare its performance with a recent genome-scale species tree reconstruction method PHYLDOG (Boussau B, Szöllősi GJ, Duret L, Gouy M, Tannier E, Daubin V. 2013. Genome-scale coestimation of species and gene trees. Genome Res. 23(2):323-330) as well as with a fast parsimony-based algorithm Duptree (Wehe A, Bansal MS, Burleigh JG, Eulenstein O. 2008. Duptree: a program for large-scale phylogenetic

  14. Unmanned Aerial Vehicles for Alien Plant Species Detection and Monitoring

    NASA Astrophysics Data System (ADS)

    Dvořák, P.; Müllerová, J.; Bartaloš, T.; Brůna, J.

    2015-08-01

    Invasive species spread rapidly and their eradication is difficult. New methods enabling fast and efficient monitoring are urgently needed for their successful control. Remote sensing can improve early detection of invading plants and make their management more efficient and less expensive. In an ongoing project in the Czech Republic, we aim at developing innovative methods of mapping invasive plant species (semi-automatic detection algorithms) by using purposely designed unmanned aircraft (UAV). We examine possibilities for detection of two tree and two herb invasive species. Our aim is to establish fast, repeatable and efficient computer-assisted method of timely monitoring, reducing the costs of extensive field campaigns. For finding the best detection algorithm we test various classification approaches (object-, pixel-based and hybrid). Thanks to its flexibility and low cost, UAV enables assessing the effect of phenological stage and spatial resolution, and is most suitable for monitoring the efficiency of eradication efforts. However, several challenges exist in UAV application, such as geometrical and radiometric distortions, high amount of data to be processed and legal constrains for the UAV flight missions over urban areas (often highly invaded). The newly proposed UAV approach shall serve invasive species researchers, management practitioners and policy makers.

  15. Effect of the Internet Commerce on Dispersal Modes of Invasive Alien Species

    PubMed Central

    Lenda, Magdalena; Skórka, Piotr; Knops, Johannes M. H.; Moroń, Dawid; Sutherland, William J.; Kuszewska, Karolina; Woyciechowski, Michał

    2014-01-01

    The spread of invasive alien plants has considerable environmental and economic consequences, and is one of the most challenging ecological problems. The spread of invasive alien plant species depends largely on long-distance dispersal, which is typically linked with human activity. The increasing domination of the internet will have impacts upon almost all components of our lives, including potential consequences for the spread of invasive species. To determine whether the rise of Internet commerce has any consequences for the spread of invasive alien plant species, we studied the sale of thirteen of some of the most harmful Europe invasive alien plant species sold as decorative plants from twenty-eight large, well known gardening shops in Poland that sold both via the Internet and through traditional customer sales. We also analyzed temporal changes in the number of invasive plants sold in the largest Polish internet auction portal. When sold through the Internet invasive alien plant species were transported considerably longer distances than for traditional sales. For internet sales, seeds of invasive alien plant species were transported further than were live plants saplings; this was not the case for traditional sales. Also, with e-commerce the shape of distance distribution were flattened with low skewness comparing with traditional sale where the distributions were peaked and right-skewed. Thus, e-commerce created novel modes of long-distance dispersal, while traditional sale resembled more natural dispersal modes. Moreover, analysis of sale in the biggest Polish internet auction portal showed that the number of alien specimens sold via the internet has increased markedly over recent years. Therefore internet commerce is likely to increase the rate at which ecological communities become homogenized and increase spread of invasive species by increasing the rate of long distance dispersal. PMID:24932498

  16. Effect of the internet commerce on dispersal modes of invasive alien species.

    PubMed

    Lenda, Magdalena; Skórka, Piotr; Knops, Johannes M H; Moroń, Dawid; Sutherland, William J; Kuszewska, Karolina; Woyciechowski, Michał

    2014-01-01

    The spread of invasive alien plants has considerable environmental and economic consequences, and is one of the most challenging ecological problems. The spread of invasive alien plant species depends largely on long-distance dispersal, which is typically linked with human activity. The increasing domination of the internet will have impacts upon almost all components of our lives, including potential consequences for the spread of invasive species. To determine whether the rise of Internet commerce has any consequences for the spread of invasive alien plant species, we studied the sale of thirteen of some of the most harmful Europe invasive alien plant species sold as decorative plants from twenty-eight large, well known gardening shops in Poland that sold both via the Internet and through traditional customer sales. We also analyzed temporal changes in the number of invasive plants sold in the largest Polish internet auction portal. When sold through the Internet invasive alien plant species were transported considerably longer distances than for traditional sales. For internet sales, seeds of invasive alien plant species were transported further than were live plants saplings; this was not the case for traditional sales. Also, with e-commerce the shape of distance distribution were flattened with low skewness comparing with traditional sale where the distributions were peaked and right-skewed. Thus, e-commerce created novel modes of long-distance dispersal, while traditional sale resembled more natural dispersal modes. Moreover, analysis of sale in the biggest Polish internet auction portal showed that the number of alien specimens sold via the internet has increased markedly over recent years. Therefore internet commerce is likely to increase the rate at which ecological communities become homogenized and increase spread of invasive species by increasing the rate of long distance dispersal. PMID:24932498

  17. Antagonistic interactions between an invasive alien and a native coccinellid species may promote coexistence.

    PubMed

    Hentley, William T; Vanbergen, Adam J; Beckerman, Andrew P; Brien, Melanie N; Hails, Rosemary S; Jones, T Hefin; Johnson, Scott N

    2016-07-01

    Despite the capacity of invasive alien species to alter ecosystems, the mechanisms underlying their impact remain only partly understood. Invasive alien predators, for example, can significantly disrupt recipient communities by consuming prey species or acting as an intraguild predator (IGP). Behavioural interactions are key components of interspecific competition between predators, yet these are often overlooked invasion processes. Here, we show how behavioural, non-lethal IGP interactions might facilitate the establishment success of an invading alien species. We experimentally assessed changes in feeding behaviour (prey preference and consumption rate) of native UK coccinellid species (Adalia bipunctata and Coccinella septempunctata), whose populations are, respectively, declining and stable, when exposed to the invasive intraguild predator, Harmonia axyridis. Using a population dynamics model parameterized with these experimental data, we predicted how intraguild predation, accommodating interspecific behavioural interactions, might impact the abundance of the native and invasive alien species over time. When competing for the same aphid resource, the feeding rate of A. bipunctata significantly increased compared to the feeding in isolation, while the feeding rate of H. axyridis significantly decreased. This suggests that despite significant declines in the UK, A. bipunctata is a superior competitor to the intraguild predator H. axyridis. In contrast, the behaviour of non-declining C. septempunctata was unaltered by the presence of H. axyridis. Our experimental data show the differential behavioural plasticity of competing native and invasive alien predators, but do not explain A. bipunctata declines observed in the UK. Using behavioural plasticity as a parameter in a population dynamic model for A. bipunctata and H. axyridis, coexistence is predicted between the native and invasive alien following an initial period of decline in the native species. We

  18. Reconciliation of Gene and Species Trees

    PubMed Central

    Rusin, L. Y.; Lyubetskaya, E. V.; Gorbunov, K. Y.; Lyubetsky, V. A.

    2014-01-01

    The first part of the paper briefly overviews the problem of gene and species trees reconciliation with the focus on defining and algorithmic construction of the evolutionary scenario. Basic ideas are discussed for the aspects of mapping definitions, costs of the mapping and evolutionary scenario, imposing time scales on a scenario, incorporating horizontal gene transfers, binarization and reconciliation of polytomous trees, and construction of species trees and scenarios. The review does not intend to cover the vast diversity of literature published on these subjects. Instead, the authors strived to overview the problem of the evolutionary scenario as a central concept in many areas of evolutionary research. The second part provides detailed mathematical proofs for the solutions of two problems: (i) inferring a gene evolution along a species tree accounting for various types of evolutionary events and (ii) trees reconciliation into a single species tree when only gene duplications and losses are allowed. All proposed algorithms have a cubic time complexity and are mathematically proved to find exact solutions. Solving algorithms for problem (ii) can be naturally extended to incorporate horizontal transfers, other evolutionary events, and time scales on the species tree. PMID:24800245

  19. The generic impact scoring system (GISS): a standardized tool to quantify the impacts of alien species.

    PubMed

    Nentwig, Wolfgang; Bacher, Sven; Pyšek, Petr; Vilà, Montserrat; Kumschick, Sabrina

    2016-05-01

    Alien species can exert negative environmental and socio-economic impacts. Therefore, administrations from different sectors are trying to prevent further introductions, stop the spread of established species, and apply or develop programs to mitigate their impact, to contain the most harmful species, or to eradicate them if possible. Often it is not clear which of the numerous alien species are most important in terms of damage, and therefore, impact scoring systems have been developed to allow a comparison and thus prioritization of species. Here, we present the generic impact scoring system (GISS), which relies on published evidence of environmental and socio-economic impact of alien species. We developed a system of 12 impact categories, for environmental and socio-economic impact, comprising all kinds of impacts that an alien species may exert. In each category, the intensity of impact is quantified by a six-level scale ranging from 0 (no impact detectable) to 5 (the highest impact possible). Such an approach, where impacts are grouped based on mechanisms for environmental impacts and receiving sectors for socio-economy, allows for cross-taxa comparisons and prioritization of the most damaging species. The GISS is simple and transparent, can be conducted with limited funds, and can be applied to a large number of alien species across taxa and environments. Meanwhile, the system was applied to 349 alien animal and plant species. In a comparison with 22 other impact assessment methods, the combination of environmental and socio-economic impact, as well as the possibility of weighting and ranking of the scoring results make GISS the most broadly applicable system. PMID:27129597

  20. Evaluation of online information sources on alien species in Europe: the need of harmonization and integration.

    PubMed

    Gatto, Francesca; Katsanevakis, Stelios; Vandekerkhove, Jochen; Zenetos, Argyro; Cardoso, Ana Cristina

    2013-06-01

    Europe is severely affected by alien invasions, which impact biodiversity, ecosystem services, economy, and human health. A large number of national, regional, and global online databases provide information on the distribution, pathways of introduction, and impacts of alien species. The sufficiency and efficiency of the current online information systems to assist the European policy on alien species was investigated by a comparative analysis of occurrence data across 43 online databases. Large differences among databases were found which are partially explained by variations in their taxonomical, environmental, and geographical scopes but also by the variable efforts for continuous updates and by inconsistencies on the definition of "alien" or "invasive" species. No single database covered all European environments, countries, and taxonomic groups. In many European countries national databases do not exist, which greatly affects the quality of reported information. To be operational and useful to scientists, managers, and policy makers, online information systems need to be regularly updated through continuous monitoring on a country or regional level. We propose the creation of a network of online interoperable web services through which information in distributed resources can be accessed, aggregated and then used for reporting and further analysis at different geographical and political scales, as an efficient approach to increase the accessibility of information. Harmonization, standardization, conformity on international standards for nomenclature, and agreement on common definitions of alien and invasive species are among the necessary prerequisites. PMID:23609303

  1. Evaluation of Online Information Sources on Alien Species in Europe: The Need of Harmonization and Integration

    NASA Astrophysics Data System (ADS)

    Gatto, Francesca; Katsanevakis, Stelios; Vandekerkhove, Jochen; Zenetos, Argyro; Cardoso, Ana Cristina

    2013-06-01

    Europe is severely affected by alien invasions, which impact biodiversity, ecosystem services, economy, and human health. A large number of national, regional, and global online databases provide information on the distribution, pathways of introduction, and impacts of alien species. The sufficiency and efficiency of the current online information systems to assist the European policy on alien species was investigated by a comparative analysis of occurrence data across 43 online databases. Large differences among databases were found which are partially explained by variations in their taxonomical, environmental, and geographical scopes but also by the variable efforts for continuous updates and by inconsistencies on the definition of "alien" or "invasive" species. No single database covered all European environments, countries, and taxonomic groups. In many European countries national databases do not exist, which greatly affects the quality of reported information. To be operational and useful to scientists, managers, and policy makers, online information systems need to be regularly updated through continuous monitoring on a country or regional level. We propose the creation of a network of online interoperable web services through which information in distributed resources can be accessed, aggregated and then used for reporting and further analysis at different geographical and political scales, as an efficient approach to increase the accessibility of information. Harmonization, standardization, conformity on international standards for nomenclature, and agreement on common definitions of alien and invasive species are among the necessary prerequisites.

  2. Alien molluscan species established along the Italian shores: an update, with discussions on some Mediterranean “alien species” categories

    PubMed Central

    Crocetta, Fabio; Macali, Armando; Furfaro, Giulia; Cooke, Samantha; Guido Villani; Valdés, Ángel

    2013-01-01

    Abstract The state of knowledge of the alien marine Mollusca in Italy is reviewed and updated. Littorina saxatilis (Olivi, 1792), Polycera hedgpethi Er. Marcus, 1964 and Haminoea japonica Pilsbry, 1895are here considered as established on the basis of published and unpublished data, and recent records of the latter considerably expand its known Mediterranean range to the Tyrrhenian Sea. COI sequences obtained indicate that a comprehensive survey of additional European localities is needed to elucidate the dispersal pathways of Haminoea japonica.Recent records and interpretation of several molluscan taxa as alien are discussed both in light of new Mediterranean (published and unpublished) records and of four categories previously excluded from alien species lists. Within this framework, ten taxa are no longer considered as alien species, or their records from Italy are refuted. Furthermore, Trochocochlea castriotae Bellini, 1903 is considered a new synonym for Gibbula albida (Gmelin, 1791). Data provided here leave unchanged as 35 the number of alien molluscan taxa recorded from Italy as well as the percentage of the most plausible vectors of introduction, but raise to 22 the number of established species along the Italian shores during the 2005–2010 period, and backdate to 1792 the first introduction of an alien molluscan species (Littorina saxatilis) to the Italian shores. PMID:23794825

  3. Preventing, controlling, and managing alien species introduction for the health of aquatic and marine ecosystems

    USGS Publications Warehouse

    Short, C.I.; Gross, S.K.; Wilkinson, D.

    2004-01-01

    The introduction and spread of invasive species is an emerging global problem. As economic and ecological impacts continue to grow, there will be an increasing need to develop innovative solutions and global partnerships to combat the increasing rate of invasions and their accompanying impacts. Threats to sustainable fisheries in North America associated with alien species come from many global directions and sources and can be deliberate or the unintended consequence of other actions. Decisions about the role of sustainable fisheries in protecting and restoring the health of aquatic ecosystems become even more complex when economic and social factors are considered along with environmental impacts, because many intentionally introduced species also have associated economic and community costs and benefits. Actions designed to prevent or control alien species in an aquatic ecosystem are often complicated by these nonenvironmental factors as well as public perception and opinion. Aquatic ecosystems are disturbed to varying degrees by alien species, including disease organisms. Prevention is the first and best line of defense. Determining likely pathways and effective countermeasures is more cost-effective than either eradication or control. Our ability to quickly identify new species and their associated risk to ecosystems is critical in designing and implementing effective control and management actions. Lack of infrastructure and necessary resources, clear-cut authority for regulation and action, and scientific information about the biology of alien species and effective control techniques are often limiting factors that prevent the needed action to protect aquatic ecosystems.

  4. Pushing the pace of tree species migration.

    PubMed

    Lazarus, Eli D; McGill, Brian J

    2014-01-01

    Plants and animals have responded to past climate changes by migrating with habitable environments, sometimes shifting the boundaries of their geographic ranges by tens of kilometers per year or more. Species migrating in response to present climate conditions, however, must contend with landscapes fragmented by anthropogenic disturbance. We consider this problem in the context of wind-dispersed tree species. Mechanisms of long-distance seed dispersal make these species capable of rapid migration rates. Models of species-front migration suggest that even tree species with the capacity for long-distance dispersal will be unable to keep pace with future spatial changes in temperature gradients, exclusive of habitat fragmentation effects. Here we present a numerical model that captures the salient dynamics of migration by long-distance dispersal for a generic tree species. We then use the model to explore the possible effects of assisted colonization within a fragmented landscape under a simulated tree-planting scheme. Our results suggest that an assisted-colonization program could accelerate species-front migration rates enough to match the speed of climate change, but such a program would involve an environmental-sustainability intervention at a massive scale. PMID:25162663

  5. Pushing the Pace of Tree Species Migration

    PubMed Central

    Lazarus, Eli D.; McGill, Brian J.

    2014-01-01

    Plants and animals have responded to past climate changes by migrating with habitable environments, sometimes shifting the boundaries of their geographic ranges by tens of kilometers per year or more. Species migrating in response to present climate conditions, however, must contend with landscapes fragmented by anthropogenic disturbance. We consider this problem in the context of wind-dispersed tree species. Mechanisms of long-distance seed dispersal make these species capable of rapid migration rates. Models of species-front migration suggest that even tree species with the capacity for long-distance dispersal will be unable to keep pace with future spatial changes in temperature gradients, exclusive of habitat fragmentation effects. Here we present a numerical model that captures the salient dynamics of migration by long-distance dispersal for a generic tree species. We then use the model to explore the possible effects of assisted colonization within a fragmented landscape under a simulated tree-planting scheme. Our results suggest that an assisted-colonization program could accelerate species-front migration rates enough to match the speed of climate change, but such a program would involve an environmental-sustainability intervention at a massive scale. PMID:25162663

  6. Region effects influence local tree species diversity

    PubMed Central

    Ricklefs, Robert E.; He, Fangliang

    2016-01-01

    Global patterns of biodiversity reflect both regional and local processes, but the relative importance of local ecological limits to species coexistence, as influenced by the physical environment, in contrast to regional processes including species production, dispersal, and extinction, is poorly understood. Failure to distinguish regional influences from local effects has been due, in part, to sampling limitations at small scales, environmental heterogeneity within local or regional samples, and incomplete geographic sampling of species. Here, we use a global dataset comprising 47 forest plots to demonstrate significant region effects on diversity, beyond the influence of local climate, which together explain more than 92% of the global variation in local forest tree species richness. Significant region effects imply that large-scale processes shaping the regional diversity of forest trees exert influence down to the local scale, where they interact with local processes to determine the number of coexisting species. PMID:26733680

  7. Region effects influence local tree species diversity.

    PubMed

    Ricklefs, Robert E; He, Fangliang

    2016-01-19

    Global patterns of biodiversity reflect both regional and local processes, but the relative importance of local ecological limits to species coexistence, as influenced by the physical environment, in contrast to regional processes including species production, dispersal, and extinction, is poorly understood. Failure to distinguish regional influences from local effects has been due, in part, to sampling limitations at small scales, environmental heterogeneity within local or regional samples, and incomplete geographic sampling of species. Here, we use a global dataset comprising 47 forest plots to demonstrate significant region effects on diversity, beyond the influence of local climate, which together explain more than 92% of the global variation in local forest tree species richness. Significant region effects imply that large-scale processes shaping the regional diversity of forest trees exert influence down to the local scale, where they interact with local processes to determine the number of coexisting species. PMID:26733680

  8. Life-history traits of alien and native senecio species in the Mediterranean region

    NASA Astrophysics Data System (ADS)

    Sans, F. X.; Garcia-Serrano, H.; Afán, I.

    2004-12-01

    Two related shrubs, Senecio inaequidens and S. pterophorus, both introduced to western Mediterranean Europe from South Africa, were compared with a native Mediterranean shrub, S. malacitanus, to identify life-history traits that confer invasive ability. We examined ecological interactions that affect seedling emergence and establishment, flowering time, growth and reproduction and competitive ability in these three closely related species. Seeds were planted, the seedlings were then transplanted and individual performance was evaluated with respect to: (1) competition with plant neighbours and (2) resource addition. Senecio inaequidens had higher rates of seedling establishment and a shorter pre-reproductive period. Competition with neighbours had a considerable impact on S. malacitanus, delaying flowering time and reducing growth and reproduction. S. pterophorus showed inefficient seedling establishment compared to the other two species, but performed better in terms of growth and reproduction. The two alien species were markedly more competitive than the native one. However, differences in competitiveness among S. malacitanus and the two aliens varied depending on resource availability. Thus, Senecio inaequidens and S. pterophorus were more affected by competition in subplots with resource addition and by competition in those without addition, respectively. The latter showed a greater capacity to respond to additional resources in competitive environments and, in addition, its reproductive effort was unrelated to habitat conditions. The invasive potential of the alien species was higher than that of the native. This was a result of various biological characteristics and specific interactions between invader and environment, which made the invasiveness of alien species unpredictable.

  9. Strategy to control the invasive alien tree Miconia calvescens in Pacific islands: Eradication, containment or something else?

    USGS Publications Warehouse

    Meyer, Jean-Yves; Loope, Lloyd; Goarant, Anne-Claire

    2011-01-01

    Miconia calvescens (Melastomataceae) is a notorious plant invader in the tropical islands of French Polynesia, Hawaii and New Caledonia. A small tree native to Central and South America, it was first introduced as an ornamental in private botanic gardens in Tahiti (1937), Honolulu (1961), and Nouméa (1970s) where it escaped, became naturalised, and formed dense monospecific stands. More than 80,000 ha are currently invaded in French Polynesia, 10,000 ha in the Hawaiian Islands and 140 ha in New Caledonia. Control programmes have been under way in the Hawaiian Islands (Oahu, Maui, Hawaii, Kauai) and French Polynesia (Raiatea, Tahaa, Nuku Hiva, Fatu Hiva) since the early 1990s, and in New Caledonia (Province Sud) since 2006. Despite more than 15 years of intensive control efforts and millions of plants destroyed, eradication has not been achieved in any of these islands, mainly because the species has multiple features that thwart its elimination (e.g., prolific seed production, active dispersal by alien and native frugivorous birds, large and persistent soil seed bank, shade-tolerance), combined with the difficulty of detecting and destroying plants on rough terrain and steep slopes, insufficient control frequency, and limited financial and human resources. Miconia’s life cycle requires at least four years growth from seedling to fruiting. Consequently, prevention of fruit production may be an effective management strategy for small populations. This “juvenilization” process may allow the eradication of small populations when carefully conducted over a quarter century. 

  10. Missing the Boat on Invasive Alien Species: A Review of Post-Secondary Curricula in Canada

    ERIC Educational Resources Information Center

    Smith, Andrea L.; Bazely, Dawn R.; Yan, Norman D.

    2011-01-01

    Invasive alien species (IAS) cause major environmental and economic damage worldwide, and also threaten human food security and health. The impacts of IAS are expected to rise with continued globalization, land use modification, and climate change. Developing effective strategies to deal with IAS requires a collaborative, interdisciplinary…

  11. ALIEN SPECIES IMPORTANTANCE IN NATIVE VEGETATION ALONG WADEABLE STREAMS, JOHN DAY RIVER BASIN, OREGON, USA

    EPA Science Inventory

    We evaluated the importance of alien species in existing vegetation along wadeable streams of a large, topographically diverse river basin in eastern Oregon, USA; sampling 165 plots (30 × 30 m) across 29 randomly selected 1-km stream reaches. Plots represented eight streamside co...

  12. Flowering phenology of invasive alien plant species compared with native species in three Mediterranean-type ecosystems

    PubMed Central

    Godoy, Oscar; Richardson, David M.; Valladares, Fernando; Castro-Díez, Pilar

    2009-01-01

    Background and Aims Flowering phenology is a potentially important component of success of alien species, since elevated fecundity may enhance invasiveness. The flowering patterns of invasive alien plant species and related natives were studied in three regions with Mediterranean-type climate: California, Spain and South Africa's Cape region. Methods A total of 227 invasive–native pairs were compared for seven character types across the regions, with each pair selected on the basis that they shared the same habitat type within a region, had a common growth form and pollination type, and belonged to the same family or genus. Key Results Invasive alien plant species have different patterns of flowering phenology from native species in the three regions. Whether the alien species flower earlier, later or at the same time as natives depends on the climatic regime in the native range of the aliens and the proportion of species in the invasive floras originating from different regions. Species invading at least two of the regions displayed the same flowering pattern, showing that flowering phenology is a conservative trait. Invasive species with native ranges in temperate climates flower earlier than natives, those from Mediterranean-type climates at the same time, and species from tropical climates flower later. In California, where the proportion of invaders from the Mediterranean Basin is high, the flowering pattern did not differ between invasive and native species, whereas in Spain the high proportion of tropical species results in a later flowering than natives, and in the Cape region early flowering than natives was the result of a high proportion of temperate invaders. Conclusions Observed patterns are due to the human-induced sympatry of species with different evolutionary histories whose flowering phenology evolved under different climatic regimes. The severity of the main abiotic filters imposed by the invaded regions (e.g. summer drought) has not been

  13. Are Photosynthetic Characteristics and Energetic Cost Important Invasive Traits for Alien Sonneratia Species in South China?

    PubMed Central

    Li, Feng-Lan; Zan, Qi-Jie; Hu, Zheng-Yu; Shin, Paul-K. S.; Cheung, Siu-Gin; Wong, Yuk-Shan; Tam, Nora Fung-Yee; Lei, An-Ping

    2016-01-01

    A higher photosynthesis and lower energetic cost are recognized as important characteristics for invasive species, but whether these traits are also important for the ability of alien mangrove species to become invasive has seldom been reported. A microcosm study was conducted to compare the photosynthetic characteristics, energetic cost indices and other growth traits between two alien species (Sonneratia apetala and S. caseolaris) and four native mangrove species over four seasons in a subtropical mangrove nature reserve in Shenzhen, South China. The aim of the study was to evaluate the invasive potential of Sonneratia based on these physiological responses. The annual average net photosynthetic rate (Pn), stomatal conductance (Gs) and total carbon assimilation per unit leaf area (Atotal) of the two alien Sonneratia species were significantly higher than the values of the native mangroves. In contrast, the opposite results were obtained for the leaf construction cost (CC) per unit dry mass (CCM) and CC per unit area (CCA) values. The higher Atotal and lower CC values resulted in a 72% higher photosynthetic energy-use efficiency (PEUE) for Sonneratia compared to native mangroves, leading to a higher relative growth rate (RGR) of the biomass and height of Sonneratia with the respective values being 51% and 119% higher than those of the native species. Higher photosynthetic indices for Sonneratia compared to native species were found in all seasons except winter, whereas lower CC values were found in all four seasons. The present findings reveal that alien Sonneratia species may adapt well and become invasive in subtropical mangrove wetlands in Shenzhen due to their higher photosynthetic characteristics coupled with lower costs in energy use, leading to a higher PEUE. The comparison of these physiological responses between S. apetala and S. caseolaris reveal that the former species is more invasive than the latter one, thus requiring more attention in future. PMID

  14. Alien Roadside Species More Easily Invade Alpine than Lowland Plant Communities in a Subarctic Mountain Ecosystem

    PubMed Central

    Lembrechts, Jonas J.; Milbau, Ann; Nijs, Ivan

    2014-01-01

    Effects of roads on plant communities are not well known in cold-climate mountain ecosystems, where road building and development are expected to increase in future decades. Knowledge of the sensitivity of mountain plant communities to disturbance by roads is however important for future conservation purposes. We investigate the effects of roads on species richness and composition, including the plant strategies that are most affected, along three elevational gradients in a subarctic mountain ecosystem. We also examine whether mountain roads promote the introduction and invasion of alien plant species from the lowlands to the alpine zone. Observations of plant community composition were made together with abiotic, biotic and anthropogenic factors in 60 T-shaped transects. Alpine plant communities reacted differently to road disturbances than their lowland counterparts. On high elevations, the roadside species composition was more similar to that of the local natural communities. Less competitive and ruderal species were present at high compared with lower elevation roadsides. While the effects of roads thus seem to be mitigated in the alpine environment for plant species in general, mountain plant communities are more invasible than lowland communities. More precisely, relatively more alien species present in the roadside were found to invade into the surrounding natural community at high compared to low elevations. We conclude that effects of roads and introduction of alien species in lowlands cannot simply be extrapolated to the alpine and subarctic environment. PMID:24586947

  15. Does Global Warming Increase Establishment Rates of Invasive Alien Species? A Centurial Time Series Analysis

    PubMed Central

    Huang, Dingcheng; Haack, Robert A.; Zhang, Runzhi

    2011-01-01

    Background The establishment rate of invasive alien insect species has been increasing worldwide during the past century. This trend has been widely attributed to increased rates of international trade and associated species introductions, but rarely linked to environmental change. To better understand and manage the bioinvasion process, it is crucial to understand the relationship between global warming and establishment rate of invasive alien species, especially for poikilothermic invaders such as insects. Methodology/Principal Findings We present data that demonstrate a significant positive relationship between the change in average annual surface air temperature and the establishment rate of invasive alien insects in mainland China during 1900–2005. This relationship was modeled by regression analysis, and indicated that a 1°C increase in average annual surface temperature in mainland China was associated with an increase in the establishment rate of invasive alien insects of about 0.5 species year−1. The relationship between rising surface air temperature and increasing establishment rate remained significant even after accounting for increases in international trade during the period 1950–2005. Moreover, similar relationships were detected using additional data from the United Kingdom and the contiguous United States. Conclusions/Significance These findings suggest that the perceived increase in establishments of invasive alien insects can be explained only in part by an increase in introduction rate or propagule pressure. Besides increasing propagule pressure, global warming is another driver that could favor worldwide bioinvasions. Our study highlights the need to consider global warming when designing strategies and policies to deal with bioinvasions. PMID:21931837

  16. Urban Power Line Corridors as Novel Habitats for Grassland and Alien Plant Species in South-Western Finland.

    PubMed

    Lampinen, Jussi; Ruokolainen, Kalle; Huhta, Ari-Pekka

    2015-01-01

    Regularly managed electric power line corridors may provide habitats for both early-successional grassland plant species and disturbance-dependent alien plant species. These habitats are especially important in urban areas, where they can help conserve native grassland species and communities in urban greenspace. However, they can also provide further footholds for potentially invasive alien species that already characterize urban areas. In order to implement power line corridors into urban conservation, it is important to understand which environmental conditions in the corridors favor grassland species and which alien species. Likewise it is important to know whether similar environmental factors in the corridors control the species composition of the two groups. We conducted a vegetation study in a 43 kilometer long urban power line corridor network in south-western Finland, and used generalized linear models and distance-based redundancy analysis to determine which environmental factors best predict the occurrence and composition of grassland and alien plant species in the corridors. The results imply that old corridors on dry soils and steep slopes characterized by a history as open areas and pastures are especially suitable for grassland species. Corridors suitable for alien species, in turn, are characterized by productive soils and abundant light and are surrounded by a dense urban fabric. Factors controlling species composition in the two groups are somewhat correlated, with the most important factors including light abundance, soil moisture, soil calcium concentration and soil productivity. The results have implications for grassland conservation and invasive alien species control in urban areas. PMID:26565700

  17. Urban Power Line Corridors as Novel Habitats for Grassland and Alien Plant Species in South-Western Finland

    PubMed Central

    Lampinen, Jussi; Ruokolainen, Kalle; Huhta, Ari-Pekka

    2015-01-01

    Regularly managed electric power line corridors may provide habitats for both early-successional grassland plant species and disturbance-dependent alien plant species. These habitats are especially important in urban areas, where they can help conserve native grassland species and communities in urban greenspace. However, they can also provide further footholds for potentially invasive alien species that already characterize urban areas. In order to implement power line corridors into urban conservation, it is important to understand which environmental conditions in the corridors favor grassland species and which alien species. Likewise it is important to know whether similar environmental factors in the corridors control the species composition of the two groups. We conducted a vegetation study in a 43 kilometer long urban power line corridor network in south-western Finland, and used generalized linear models and distance-based redundancy analysis to determine which environmental factors best predict the occurrence and composition of grassland and alien plant species in the corridors. The results imply that old corridors on dry soils and steep slopes characterized by a history as open areas and pastures are especially suitable for grassland species. Corridors suitable for alien species, in turn, are characterized by productive soils and abundant light and are surrounded by a dense urban fabric. Factors controlling species composition in the two groups are somewhat correlated, with the most important factors including light abundance, soil moisture, soil calcium concentration and soil productivity. The results have implications for grassland conservation and invasive alien species control in urban areas. PMID:26565700

  18. TEASIng apart alien species risk assessments: a framework for best practices.

    PubMed

    Leung, Brian; Roura-Pascual, Nuria; Bacher, Sven; Heikkilä, Jaakko; Brotons, Lluis; Burgman, Mark A; Dehnen-Schmutz, Katharina; Essl, Franz; Hulme, Philip E; Richardson, David M; Sol, Daniel; Vilà, Montserrat; Rejmanek, Marcel

    2012-12-01

    Some alien species cause substantial impacts, yet most are innocuous. Given limited resources, forecasting risks from alien species will help prioritise management. Given that risk assessment (RA) approaches vary widely, a synthesis is timely to highlight best practices. We reviewed quantitative and scoring RAs, integrating > 300 publications into arguably the most rigorous quantitative RA framework currently existing, and mapping each study onto our framework, which combines Transport, Establishment, Abundance, Spread and Impact (TEASI). Quantitative models generally measured single risk components (78% of studies), often focusing on Establishment alone (79%). Although dominant in academia, quantitative RAs are underused in policy, and should be made more accessible. Accommodating heterogeneous limited data, combining across risk components, and developing generalised RAs across species, space and time without requiring new models for each species may increase attractiveness for policy applications. Comparatively, scoring approaches covered more risk components (50% examined > 3 components), with Impact being the most common component (87%), and have been widely applied in policy (> 57%), but primarily employed expert opinion. Our framework provides guidance for questions asked, combining scores and other improvements. Our risk framework need not be completely parameterised to be informative, but instead identifies opportunities for improvement in alien species RA. PMID:23020170

  19. A tree species inventory over Europe

    NASA Astrophysics Data System (ADS)

    Ambelas Skjøth, C.; Geels, C.; Hvidberg, M.; Hertel, O.; Brandt, J.; Frohn, L. M.; Hansen, K. M.; Hedegaard, G. B.; Christensen, J. H.; Moseholm, L.

    2009-04-01

    Atmospheric transport models are used in studies of atmospheric chemistry as well as aerobiology. Atmospheric transport models in general needs accurate emissions inventories, which includes biogenic emissions such as Volatile Organic Compounds (VOCs) and pollen. Trees are important VOC and pollen sources and a needed requirement is specie distribution which takes into account important species such as Betula and Alnus. We present here a detailed tree species inventory covering Europe, parts of Africa and parts of Asia. Forest inventories have been obtained for each European country, parts of Asia and parts of Africa. The national inventories vary with respect to number of species as well as the number of sub-regions each nation is divided into. The inventories are therefore harmonised within a GIS system and afterwards gridded to the model grid defined by the EMEP model: 50 km x 50 km. The inventory is designed to be used with existing land-use data, which separates forest cover into broad leaved, mixed and conifer forests. This will be exemplified by using two different remote sensing products with different grid resolution such as GLC2000 and CLC2000 in selected areas. The final inventory includes 16 conifer species and 23 broadleaved species that are important for biogenic VOCs or pollen emission calculations. For example: Oak (Quercus), poplar (Populus), pines (Pinus), spruce (Picea), birch (Betula) and alder (Alnus). 774 regions with forest inventories are included, mainly on sub-national level. The coverage of each specie ranges from national to European scale, where the latter includes VOC and allergy relevant species such as Quercus, Alnus and Betula. The inventory is gridded to the model grid defined by the EMEP model, which is also the basis for many emissions inventories throughout Europe. The inventory is therefore prepared for easy implementation into atmospheric transport models by providing an extension to already applied land use data such as the

  20. Screening Allelochemical-Resistant Species of the Alien Invasive Mikania micrantha for Restoration in South China

    PubMed Central

    Wu, Ai-Ping; Li, Zi-Li; He, Fei-Fei; Wang, Yan-Hong; Dong, Ming

    2015-01-01

    To screen allelochemical-resistant species of the alien invasive weed Mikania micrantha, we studied the allelopathic inhibition effects of the leaf aqueous extract (LAE) of Mikania on seed germination and seedling growth of the 26 species native or naturalized in the invaded region in South China. Seed germination was more strongly negatively affected by LAE than seedling growth. Responses of seed germination and seed growth to LAE differed differently among the target species. LAE more strongly negatively affected seed germination, but less strongly negatively affected seedling growth, in non-legume species than in legume species. LAE more strongly negatively affected seed germination and seedling growth in native species than naturalized exotic species. Therefore, naturalized exotic non-legume seedlings are more suitable than seeds of native legume species for restoration of Mikania-invaded habitats. PMID:26177031

  1. Insect Eradication and Containment of Invasive Alien Species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Insect eradication programs are nearly always targeted at recently arrived invasive species with significant pest potential. They attempt to contain a pest to a defined area and then completely eliminate the pest from that area. From a Federal regulatory standpoint, eradication programs are undert...

  2. Dispersal limitation does not control high elevational distribution of alien plant species in the southern Sierra Nevada, California

    USGS Publications Warehouse

    Rundel, Philip W.; Keeley, Jon E.

    2016-01-01

    Patterns of elevational distribution of alien plant species in the southern Sierra Nevada of California were used to test the hypothesis that alien plant species invading high elevations around the world are typically climate generalists capable of growing across a wide elevational range. The Sierra Nevada has been heavily impacted for more than a century and a half, first by heavy grazing up into high elevation meadows, followed by major logging, and finally, by impacts associated with recreational use. The comparative elevational patterns of distribution and growth form were compared for native and alien plant species in the four families (Asteraceae, Brassicaceae, Fabaceae, and Poaceae) that contribute the majority of naturalized aliens in the study area. The distribution of realized climatic niche breadth, as measured by elevational range of occurrence, was virtually identical for alien and native species, with both groups showing a roughly Gaussian distribution peaking with species whose range covers a span of 1500–1999 m. In contrast to alien species, which only rarely occurred at higher elevations, native species showed a distribution of upper elevation limits peaking at 3000–3499 m, an elevation that corresponds to the zone of upper montane and subalpine forests. Consistent with a hypothesis of abiotic limitations, only a few alien species have been ecologically successful invaders at subalpine and alpine elevations above 2500 m. The low diversity of aliens able to become established in these habitats is unlikely due to dispersal limitations, given the long history of heavy grazing pressure at high elevations across this region. Instead, this low diversity is hypothesized to be a function of life history traits and multiple abiotic stresses that include extremes of cold air and soil temperature, heavy snowfall, short growing seasons, and low resource availability. These findings have significant implications for resource managers.

  3. A unified classification of alien species based on the magnitude of their environmental impacts.

    PubMed

    Blackburn, Tim M; Essl, Franz; Evans, Thomas; Hulme, Philip E; Jeschke, Jonathan M; Kühn, Ingolf; Kumschick, Sabrina; Marková, Zuzana; Mrugała, Agata; Nentwig, Wolfgang; Pergl, Jan; Pyšek, Petr; Rabitsch, Wolfgang; Ricciardi, Anthony; Richardson, David M; Sendek, Agnieszka; Vilà, Montserrat; Wilson, John R U; Winter, Marten; Genovesi, Piero; Bacher, Sven

    2014-05-01

    Species moved by human activities beyond the limits of their native geographic ranges into areas in which they do not naturally occur (termed aliens) can cause a broad range of significant changes to recipient ecosystems; however, their impacts vary greatly across species and the ecosystems into which they are introduced. There is therefore a critical need for a standardised method to evaluate, compare, and eventually predict the magnitudes of these different impacts. Here, we propose a straightforward system for classifying alien species according to the magnitude of their environmental impacts, based on the mechanisms of impact used to code species in the International Union for Conservation of Nature (IUCN) Global Invasive Species Database, which are presented here for the first time. The classification system uses five semi-quantitative scenarios describing impacts under each mechanism to assign species to different levels of impact-ranging from Minimal to Massive-with assignment corresponding to the highest level of deleterious impact associated with any of the mechanisms. The scheme also includes categories for species that are Not Evaluated, have No Alien Population, or are Data Deficient, and a method for assigning uncertainty to all the classifications. We show how this classification system is applicable at different levels of ecological complexity and different spatial and temporal scales, and embraces existing impact metrics. In fact, the scheme is analogous to the already widely adopted and accepted Red List approach to categorising extinction risk, and so could conceivably be readily integrated with existing practices and policies in many regions. PMID:24802715

  4. A Unified Classification of Alien Species Based on the Magnitude of their Environmental Impacts

    PubMed Central

    Blackburn, Tim M.; Essl, Franz; Evans, Thomas; Hulme, Philip E.; Jeschke, Jonathan M.; Kühn, Ingolf; Kumschick, Sabrina; Marková, Zuzana; Mrugała, Agata; Nentwig, Wolfgang; Pergl, Jan; Pyšek, Petr; Rabitsch, Wolfgang; Ricciardi, Anthony; Richardson, David M.; Sendek, Agnieszka; Vilà, Montserrat; Wilson, John R. U.; Winter, Marten; Genovesi, Piero; Bacher, Sven

    2014-01-01

    Species moved by human activities beyond the limits of their native geographic ranges into areas in which they do not naturally occur (termed aliens) can cause a broad range of significant changes to recipient ecosystems; however, their impacts vary greatly across species and the ecosystems into which they are introduced. There is therefore a critical need for a standardised method to evaluate, compare, and eventually predict the magnitudes of these different impacts. Here, we propose a straightforward system for classifying alien species according to the magnitude of their environmental impacts, based on the mechanisms of impact used to code species in the International Union for Conservation of Nature (IUCN) Global Invasive Species Database, which are presented here for the first time. The classification system uses five semi-quantitative scenarios describing impacts under each mechanism to assign species to different levels of impact—ranging from Minimal to Massive—with assignment corresponding to the highest level of deleterious impact associated with any of the mechanisms. The scheme also includes categories for species that are Not Evaluated, have No Alien Population, or are Data Deficient, and a method for assigning uncertainty to all the classifications. We show how this classification system is applicable at different levels of ecological complexity and different spatial and temporal scales, and embraces existing impact metrics. In fact, the scheme is analogous to the already widely adopted and accepted Red List approach to categorising extinction risk, and so could conceivably be readily integrated with existing practices and policies in many regions. PMID:24802715

  5. Niche dynamics of alien species do not differ among sexual and apomictic flowering plants.

    PubMed

    Dellinger, Agnes S; Essl, Franz; Hojsgaard, Diego; Kirchheimer, Bernhard; Klatt, Simone; Dawson, Wayne; Pergl, Jan; Pyšek, Petr; van Kleunen, Mark; Weber, Ewald; Winter, Marten; Hörandl, Elvira; Dullinger, Stefan

    2016-02-01

    Biological invasions can be associated with shifts of the species' climatic niches but the incidence of such shifts is under debate. The reproductive system might be a key factor controlling such shifts because it influences a species' evolutionary flexibility. However, the link between reproductive systems and niche dynamics in plant invasions has been little studied so far. We compiled global occurrence data sets of 13 congeneric sexual and apomictic species pairs, and used principal components analysis (PCA) and kernel smoothers to compare changes in climatic niche optima, breadths and unfilling/expansion between native and alien ranges. Niche change metrics were compared between sexual and apomictic species. All 26 species showed changes in niche optima and/or breadth and 14 species significantly expanded their climatic niches. However, we found no effect of the reproductive system on niche dynamics. Instead, species with narrower native niches showed higher rates of niche expansion in the alien ranges. Our results suggest that niche shifts are frequent in plant invasions but evolutionary potential may not be of major importance for such shifts. Niche dynamics rather appear to be driven by changes of the realized niche without adaptive change of the fundamental climatic niche. PMID:26508329

  6. Microbiological accumulation by the Mediterranean invasive alien species Branchiomma bairdi (Annelida, Sabellidae): potential tool for bioremediation.

    PubMed

    Stabili, Loredana; Licciano, Margherita; Lezzi, Marco; Giangrande, Adriana

    2014-09-15

    We examined the bacterial accumulation and digestion in the alien polychaete Branchiomma bairdi. Microbiological analyses were performed on worm homogenates from "unstarved" and "starved" individuals and on seawater from the same sampling site (Ionian Sea, Italy). Densities of culturable heterotrophic bacteria (22 °C), total culturable bacteria (37 °C) and vibrios were measured on Marine Agar 2216, Plate Count Agar and TCBS Agar, respectively. Microbial pollution indicators were determined by the most probable number method. B. bairdi was able to accumulate all the six considered microbiological groups which, however, differ in their resistance to digestion. B. bairdi results more efficient than the other two co-occurring sabellids in removing bacteria suggesting that it may counteract the effects of microbial pollution playing a potential role for in situ bioremediation. Thus a potential risk, such as the invasion of an alien species, could be transformed into a benefit with high potential commercial gain and economic feasibility. PMID:25070411

  7. Liana competition with tropical trees varies seasonally but not with tree species identity.

    PubMed

    Leonor, Alvarez-Cansino; Schnitzer, Stefan A; Reid, Joseph P; Powers, Jennifer S

    2015-01-01

    Lianas in tropical forests compete intensely with trees for above- and belowground resources and limit tree growth and regeneration. Liana competition with adult canopy trees may be particularly strong, and, if lianas compete more intensely with some tree species than others, they may influence tree species composition. We performed the first systematic, large-scale liana removal experiment to assess the competitive effects of lianas on multiple tropical tree species by measuring sap velocity and growth in a lowland tropical forest in Panama. Tree sap velocity increased 60% soon after liana removal compared to control trees, and tree diameter growth increased 25% after one year. Although tree species varied in their response to lianas, this variation was not significant, suggesting that lianas competed similarly with all tree species examined. The effect of lianas on tree sap velocity was particularly strong during the dry season, when soil moisture was low, suggesting that lianas compete intensely with trees for water. Under the predicted global change scenario of increased temperature and drought intensity, competition from lianas may become more prevalent in seasonal tropical forests, which, according to our data, should have a negative effect on most tropical tree species. PMID:26236888

  8. The probability of topological concordance of gene trees and species trees.

    PubMed

    Rosenberg, Noah A

    2002-03-01

    The concordance of gene trees and species trees is reconsidered in detail, allowing for samples of arbitrary size to be taken from the species. A sense of concordance for gene tree and species tree topologies is clarified, such that if the "collapsed gene tree" produced by a gene tree has the same topology as the species tree, the gene tree is said to be topologically concordant with the species tree. The term speciodendric is introduced to refer to genes whose trees are topologically concordant with species trees. For a given three-species topology, probabilities of each of the three possible collapsed gene tree topologies are given, as are probabilities of monophyletic concordance and concordance in the sense of N. Takahata (1989), Genetics 122, 957-966. Increasing the sample size is found to increase the probability of topological concordance, but a limit exists on how much the topological concordance probability can be increased. Suggested sample sizes beyond which this probability can be increased only minimally are given. The results are discussed in terms of implications for molecular studies of phylogenetics and speciation. PMID:11969392

  9. Invasive species information networks: Collaboration at multiple scales for prevention, early detection, and rapid response to invasive alien species

    USGS Publications Warehouse

    Simpson, A.; Jarnevich, C.; Madsen, J.; Westbrooks, R.; Fournier, C.; Mehrhoff, L.; Browne, M.; Graham, J.; Sellers, E.

    2009-01-01

    Accurate analysis of present distributions and effective modeling of future distributions of invasive alien species (IAS) are both highly dependent on the availability and accessibility of occurrence data and natural history information about the species. Invasive alien species monitoring and detection networks (such as the Invasive Plant Atlas of New England and the Invasive Plant Atlas of the MidSouth) generate occurrence data at local and regional levels within the United States, which are shared through the US National Institute of Invasive Species Science. The Inter-American Biodiversity Information Network's Invasives Information Network (I3N), facilitates cooperation on sharing invasive species occurrence data throughout the Western Hemisphere. The I3N and other national and regional networks expose their data globally via the Global Invasive Species Information Network (GISIN). International and interdisciplinary cooperation on data sharing strengthens cooperation on strategies and responses to invasions. However, limitations to effective collaboration among invasive species networks leading to successful early detection and rapid response to invasive species include: lack of interoperability; data accessibility; funding; and technical expertise. This paper proposes various solutions to these obstacles at different geographic levels and briefly describes success stories from the invasive species information networks mentioned above. Using biological informatics to facilitate global information sharing is especially critical in invasive species science, as research has shown that one of the best indicators of the invasiveness of a species is whether it has been invasive elsewhere. Data must also be shared across disciplines because natural history information (e.g. diet, predators, habitat requirements, etc.) about a species in its native range is vital for effective prevention, detection, and rapid response to an invasion. Finally, it has been our

  10. Hybridization between alien species Rumex obtusifolius and closely related native vulnerable species R. longifolius in a mountain tourist destination

    PubMed Central

    Takahashi, Koichi; Hanyu, Masaaki

    2015-01-01

    Alien species expand their distribution by transportation network development. Hybridization between alien species Rumex obtusifolius and closely related native vulnerable species R. longifolius was examined in a mountain tourist destination in central Japan. The three taxa were morphologically identified in the field. Stem height and leaf area were greater in R. longifolius than R. obtusifolius; hybrids were intermediate between the two Rumex species. R. longifolius and the hybrids grew mainly in wet land and the river tributary; R. obtusifolius grew mainly at the roadside and in meadows. Hybrid germination rates of pollen and seeds were much lower than for the two Rumex species. Clustering analysis showed the three taxa each formed a cluster. Most hybrids were F1 generation; the possibility was low of introgression into the two Rumex species by backcross. This study clarified that (1) hybridization occurred between R. obtusifolius and R. longifolius because they occurred together in a small area, but grew in different water habitat conditions, and (2) hybridization was mostly F1 generation because hybrid pollen and seed fertility was low. However, we need caution about introgression into R. longifolius by R. obtusifolius in this area because of the slight possibility of F2 generation and backcrosses. PMID:26354180

  11. Hybridization between alien species Rumex obtusifolius and closely related native vulnerable species R. longifolius in a mountain tourist destination.

    PubMed

    Takahashi, Koichi; Hanyu, Masaaki

    2015-01-01

    Alien species expand their distribution by transportation network development. Hybridization between alien species Rumex obtusifolius and closely related native vulnerable species R. longifolius was examined in a mountain tourist destination in central Japan. The three taxa were morphologically identified in the field. Stem height and leaf area were greater in R. longifolius than R. obtusifolius; hybrids were intermediate between the two Rumex species. R. longifolius and the hybrids grew mainly in wet land and the river tributary; R. obtusifolius grew mainly at the roadside and in meadows. Hybrid germination rates of pollen and seeds were much lower than for the two Rumex species. Clustering analysis showed the three taxa each formed a cluster. Most hybrids were F1 generation; the possibility was low of introgression into the two Rumex species by backcross. This study clarified that (1) hybridization occurred between R. obtusifolius and R. longifolius because they occurred together in a small area, but grew in different water habitat conditions, and (2) hybridization was mostly F1 generation because hybrid pollen and seed fertility was low. However, we need caution about introgression into R. longifolius by R. obtusifolius in this area because of the slight possibility of F2 generation and backcrosses. PMID:26354180

  12. Exploring tree species signature using waveform LiDAR data

    NASA Astrophysics Data System (ADS)

    Zhou, T.; Popescu, S. C.; Krause, K.

    2015-12-01

    Successful classification of tree species with waveform LiDAR data would be of considerable value to estimate the biomass stocks and changes in forests. Current approaches emphasize converting the full waveform data into discrete points to get larger amount of parameters and identify tree species using several discrete-points variables. However, ignores intensity values and waveform shapes which convey important structural characteristics. The overall goal of this study was to employ the intensity and waveform shape of individual tree as the waveform signature to detect tree species. The data was acquired by the National Ecological Observatory Network (NEON) within 250*250 m study area located in San Joaquin Experimental Range. Specific objectives were to: (1) segment individual trees using the smoothed canopy height model (CHM) derived from discrete LiDAR points; (2) link waveform LiDAR with above individual tree boundaries to derive sample signatures of three tree species and use these signatures to discriminate tree species in a large area; and (3) compare tree species detection results from discrete LiDAR data and waveform LiDAR data. An overall accuracy of the segmented individual tree of more than 80% was obtained. The preliminary results show that compared with the discrete LiDAR data, the waveform LiDAR signature has a higher potential for accurate tree species classification.

  13. When does an alien become a native species? A vulnerable native mammal recognizes and responds to its long-term alien predator.

    PubMed

    Carthey, Alexandra J R; Banks, Peter B

    2012-01-01

    The impact of alien predators on native prey populations is often attributed to prey naiveté towards a novel threat. Yet evolutionary theory predicts that alien predators cannot remain eternally novel; prey species must either become extinct or learn and adapt to the new threat. As local enemies lose their naiveté and coexistence becomes possible, an introduced species must eventually become 'native'. But when exactly does an alien become a native species? The dingo (Canis lupus dingo) was introduced to Australia about 4000 years ago, yet its native status remains disputed. To determine whether a vulnerable native mammal (Perameles nasuta) recognizes the close relative of the dingo, the domestic dog (Canis lupus familiaris), we surveyed local residents to determine levels of bandicoot visitation to yards with and without resident dogs. Bandicoots in this area regularly emerge from bushland to forage in residential yards at night, leaving behind tell-tale deep, conical diggings in lawns and garden beds. These diggings were less likely to appear at all, and appeared less frequently and in smaller quantities in yards with dogs than in yards with either resident cats (Felis catus) or no pets. Most dogs were kept indoors at night, meaning that bandicoots were not simply chased out of the yards or killed before they could leave diggings, but rather they recognized the threat posed by dogs and avoided those yards. Native Australian mammals have had thousands of years experience with wild dingoes, which are very closely related to domestic dogs. Our study suggests that these bandicoots may no longer be naïve towards dogs. We argue that the logical criterion for determining native status of a long-term alien species must be once its native enemies are no longer naïve. PMID:22355396

  14. An estimate of the number of tropical tree species

    PubMed Central

    Slik, J. W. Ferry; Arroyo-Rodríguez, Víctor; Aiba, Shin-Ichiro; Alvarez-Loayza, Patricia; Alves, Luciana F.; Ashton, Peter; Balvanera, Patricia; Bastian, Meredith L.; Bellingham, Peter J.; van den Berg, Eduardo; Bernacci, Luis; da Conceição Bispo, Polyanna; Blanc, Lilian; Böhning-Gaese, Katrin; Boeckx, Pascal; Bongers, Frans; Boyle, Brad; Bradford, Matt; Brearley, Francis Q.; Breuer-Ndoundou Hockemba, Mireille; Bunyavejchewin, Sarayudh; Calderado Leal Matos, Darley; Castillo-Santiago, Miguel; Catharino, Eduardo L. M.; Chai, Shauna-Lee; Chen, Yukai; Colwell, Robert K.; Chazdon, Robin L.; Clark, Connie; Clark, David B.; Clark, Deborah A.; Culmsee, Heike; Damas, Kipiro; Dattaraja, Handanakere S.; Dauby, Gilles; Davidar, Priya; DeWalt, Saara J.; Doucet, Jean-Louis; Duque, Alvaro; Durigan, Giselda; Eichhorn, Karl A. O.; Eisenlohr, Pedro V.; Eler, Eduardo; Ewango, Corneille; Farwig, Nina; Feeley, Kenneth J.; Ferreira, Leandro; Field, Richard; de Oliveira Filho, Ary T.; Fletcher, Christine; Forshed, Olle; Franco, Geraldo; Fredriksson, Gabriella; Gillespie, Thomas; Gillet, Jean-François; Amarnath, Giriraj; Griffith, Daniel M.; Grogan, James; Gunatilleke, Nimal; Harris, David; Harrison, Rhett; Hector, Andy; Homeier, Jürgen; Imai, Nobuo; Itoh, Akira; Jansen, Patrick A.; Joly, Carlos A.; de Jong, Bernardus H. J.; Kartawinata, Kuswata; Kearsley, Elizabeth; Kelly, Daniel L.; Kenfack, David; Kessler, Michael; Kitayama, Kanehiro; Kooyman, Robert; Larney, Eileen; Laumonier, Yves; Laurance, Susan; Laurance, William F.; Lawes, Michael J.; do Amaral, Ieda Leao; Letcher, Susan G.; Lindsell, Jeremy; Lu, Xinghui; Mansor, Asyraf; Marjokorpi, Antti; Martin, Emanuel H.; Meilby, Henrik; Melo, Felipe P. L.; Metcalfe, Daniel J.; Medjibe, Vincent P.; Metzger, Jean Paul; Millet, Jerome; Mohandass, D.; Montero, Juan C.; de Morisson Valeriano, Márcio; Mugerwa, Badru; Nagamasu, Hidetoshi; Nilus, Reuben; Ochoa-Gaona, Susana; Onrizal; Page, Navendu; Parolin, Pia; Parren, Marc; Parthasarathy, Narayanaswamy; Paudel, Ekananda; Permana, Andrea; Piedade, Maria T. F.; Pitman, Nigel C. A.; Poorter, Lourens; Poulsen, Axel D.; Poulsen, John; Powers, Jennifer; Prasad, Rama C.; Puyravaud, Jean-Philippe; Razafimahaimodison, Jean-Claude; Reitsma, Jan; dos Santos, João Roberto; Roberto Spironello, Wilson; Romero-Saltos, Hugo; Rovero, Francesco; Rozak, Andes Hamuraby; Ruokolainen, Kalle; Rutishauser, Ervan; Saiter, Felipe; Saner, Philippe; Santos, Braulio A.; Santos, Fernanda; Sarker, Swapan K.; Satdichanh, Manichanh; Schmitt, Christine B.; Schöngart, Jochen; Schulze, Mark; Suganuma, Marcio S.; Sheil, Douglas; da Silva Pinheiro, Eduardo; Sist, Plinio; Stevart, Tariq; Sukumar, Raman; Sun, I.-Fang; Sunderland, Terry; Suresh, H. S.; Suzuki, Eizi; Tabarelli, Marcelo; Tang, Jangwei; Targhetta, Natália; Theilade, Ida; Thomas, Duncan W.; Tchouto, Peguy; Hurtado, Johanna; Valencia, Renato; van Valkenburg, Johan L. C. H.; Van Do, Tran; Vasquez, Rodolfo; Verbeeck, Hans; Adekunle, Victor; Vieira, Simone A.; Webb, Campbell O.; Whitfeld, Timothy; Wich, Serge A.; Williams, John; Wittmann, Florian; Wöll, Hannsjoerg; Yang, Xiaobo; Adou Yao, C. Yves; Yap, Sandra L.; Yoneda, Tsuyoshi; Zahawi, Rakan A.; Zakaria, Rahmad; Zang, Runguo; de Assis, Rafael L.; Garcia Luize, Bruno; Venticinque, Eduardo M.

    2015-01-01

    The high species richness of tropical forests has long been recognized, yet there remains substantial uncertainty regarding the actual number of tropical tree species. Using a pantropical tree inventory database from closed canopy forests, consisting of 657,630 trees belonging to 11,371 species, we use a fitted value of Fisher’s alpha and an approximate pantropical stem total to estimate the minimum number of tropical forest tree species to fall between ∼40,000 and ∼53,000, i.e., at the high end of previous estimates. Contrary to common assumption, the Indo-Pacific region was found to be as species-rich as the Neotropics, with both regions having a minimum of ∼19,000–25,000 tree species. Continental Africa is relatively depauperate with a minimum of ∼4,500–6,000 tree species. Very few species are shared among the African, American, and the Indo-Pacific regions. We provide a methodological framework for estimating species richness in trees that may help refine species richness estimates of tree-dependent taxa. PMID:26034279

  15. An estimate of the number of tropical tree species.

    PubMed

    Slik, J W Ferry; Arroyo-Rodríguez, Víctor; Aiba, Shin-Ichiro; Alvarez-Loayza, Patricia; Alves, Luciana F; Ashton, Peter; Balvanera, Patricia; Bastian, Meredith L; Bellingham, Peter J; van den Berg, Eduardo; Bernacci, Luis; da Conceição Bispo, Polyanna; Blanc, Lilian; Böhning-Gaese, Katrin; Boeckx, Pascal; Bongers, Frans; Boyle, Brad; Bradford, Matt; Brearley, Francis Q; Breuer-Ndoundou Hockemba, Mireille; Bunyavejchewin, Sarayudh; Calderado Leal Matos, Darley; Castillo-Santiago, Miguel; Catharino, Eduardo L M; Chai, Shauna-Lee; Chen, Yukai; Colwell, Robert K; Chazdon, Robin L; Robin, Chazdon L; Clark, Connie; Clark, David B; Clark, Deborah A; Culmsee, Heike; Damas, Kipiro; Dattaraja, Handanakere S; Dauby, Gilles; Davidar, Priya; DeWalt, Saara J; Doucet, Jean-Louis; Duque, Alvaro; Durigan, Giselda; Eichhorn, Karl A O; Eisenlohr, Pedro V; Eler, Eduardo; Ewango, Corneille; Farwig, Nina; Feeley, Kenneth J; Ferreira, Leandro; Field, Richard; de Oliveira Filho, Ary T; Fletcher, Christine; Forshed, Olle; Franco, Geraldo; Fredriksson, Gabriella; Gillespie, Thomas; Gillet, Jean-François; Amarnath, Giriraj; Griffith, Daniel M; Grogan, James; Gunatilleke, Nimal; Harris, David; Harrison, Rhett; Hector, Andy; Homeier, Jürgen; Imai, Nobuo; Itoh, Akira; Jansen, Patrick A; Joly, Carlos A; de Jong, Bernardus H J; Kartawinata, Kuswata; Kearsley, Elizabeth; Kelly, Daniel L; Kenfack, David; Kessler, Michael; Kitayama, Kanehiro; Kooyman, Robert; Larney, Eileen; Laumonier, Yves; Laurance, Susan; Laurance, William F; Lawes, Michael J; Amaral, Ieda Leao do; Letcher, Susan G; Lindsell, Jeremy; Lu, Xinghui; Mansor, Asyraf; Marjokorpi, Antti; Martin, Emanuel H; Meilby, Henrik; Melo, Felipe P L; Metcalfe, Daniel J; Medjibe, Vincent P; Metzger, Jean Paul; Millet, Jerome; Mohandass, D; Montero, Juan C; de Morisson Valeriano, Márcio; Mugerwa, Badru; Nagamasu, Hidetoshi; Nilus, Reuben; Ochoa-Gaona, Susana; Onrizal; Page, Navendu; Parolin, Pia; Parren, Marc; Parthasarathy, Narayanaswamy; Paudel, Ekananda; Permana, Andrea; Piedade, Maria T F; Pitman, Nigel C A; Poorter, Lourens; Poulsen, Axel D; Poulsen, John; Powers, Jennifer; Prasad, Rama C; Puyravaud, Jean-Philippe; Razafimahaimodison, Jean-Claude; Reitsma, Jan; Dos Santos, João Roberto; Roberto Spironello, Wilson; Romero-Saltos, Hugo; Rovero, Francesco; Rozak, Andes Hamuraby; Ruokolainen, Kalle; Rutishauser, Ervan; Saiter, Felipe; Saner, Philippe; Santos, Braulio A; Santos, Fernanda; Sarker, Swapan K; Satdichanh, Manichanh; Schmitt, Christine B; Schöngart, Jochen; Schulze, Mark; Suganuma, Marcio S; Sheil, Douglas; da Silva Pinheiro, Eduardo; Sist, Plinio; Stevart, Tariq; Sukumar, Raman; Sun, I-Fang; Sunderland, Terry; Sunderand, Terry; Suresh, H S; Suzuki, Eizi; Tabarelli, Marcelo; Tang, Jangwei; Targhetta, Natália; Theilade, Ida; Thomas, Duncan W; Tchouto, Peguy; Hurtado, Johanna; Valencia, Renato; van Valkenburg, Johan L C H; Van Do, Tran; Vasquez, Rodolfo; Verbeeck, Hans; Adekunle, Victor; Vieira, Simone A; Webb, Campbell O; Whitfeld, Timothy; Wich, Serge A; Williams, John; Wittmann, Florian; Wöll, Hannsjoerg; Yang, Xiaobo; Adou Yao, C Yves; Yap, Sandra L; Yoneda, Tsuyoshi; Zahawi, Rakan A; Zakaria, Rahmad; Zang, Runguo; de Assis, Rafael L; Garcia Luize, Bruno; Venticinque, Eduardo M

    2015-06-16

    The high species richness of tropical forests has long been recognized, yet there remains substantial uncertainty regarding the actual number of tropical tree species. Using a pantropical tree inventory database from closed canopy forests, consisting of 657,630 trees belonging to 11,371 species, we use a fitted value of Fisher's alpha and an approximate pantropical stem total to estimate the minimum number of tropical forest tree species to fall between ∼ 40,000 and ∼ 53,000, i.e., at the high end of previous estimates. Contrary to common assumption, the Indo-Pacific region was found to be as species-rich as the Neotropics, with both regions having a minimum of ∼ 19,000-25,000 tree species. Continental Africa is relatively depauperate with a minimum of ∼ 4,500-6,000 tree species. Very few species are shared among the African, American, and the Indo-Pacific regions. We provide a methodological framework for estimating species richness in trees that may help refine species richness estimates of tree-dependent taxa. PMID:26034279

  16. Tree species richness affecting fine root biomass in European forests

    NASA Astrophysics Data System (ADS)

    Finér, Leena; Domisch, Timo; Vesterdal, Lars; Dawud, Seid M.; Raulund-Rasmussen, Karsten

    2016-04-01

    Fine roots are an important factor in the forest carbon cycle, contributing significantly to below-ground biomass and soil carbon storage. Therefore it is essential to understand the role of the forest structure, indicated by tree species diversity in controlling below-ground biomass and managing the carbon pools of forest soils. We studied how tree species richness would affect fine root biomass and its distribution in the soil profile and biomass above- and below-ground allocation patterns of different tree species. Our main hypothesis was that increasing tree species richness would lead to below-ground niche differentiation and more efficient soil exploitation by the roots, resulting in a higher fine root biomass in the soil. We sampled fine roots of trees and understorey vegetation in six European forest types in Finland, Poland, Germany, Romania, Italy and Spain, representing boreal, temperate and Mediterranean forests, established within the FunDivEUROPE project for studying the effects of tree species diversity on forest functioning. After determining fine root biomasses, we identified the percentages of different tree species in the fine root samples using the near infrared reflectance spectroscopy (NIRS) method. Opposite to our hypothesis we did not find any general positive relationship between tree species richness and fine root biomass. A weak positive response found in Italy and Spain seemed to be related to dry environmental conditions during Mediterranean summers. At the Polish site where we could sample deeper soil layers (down to 40 cm), we found more tree fine roots in the deeper layers under species-rich forests, as compared to the monocultures, indicating the ability of trees to explore more resources and to increase soil carbon stocks. Tree species richness did not affect biomass allocation patterns between above- and below-ground parts of the trees.

  17. BIOGEOGRAPHY. The dispersal of alien species redefines biogeography in the Anthropocene.

    PubMed

    Capinha, César; Essl, Franz; Seebens, Hanno; Moser, Dietmar; Pereira, Henrique Miguel

    2015-06-12

    It has been argued that globalization in human-mediated dispersal of species breaks down biogeographic boundaries, yet empirical tests are still missing. We used data on native and alien ranges of terrestrial gastropods to analyze dissimilarities in species composition among 56 globally distributed regions. We found that native ranges confirm the traditional biogeographic realms, reflecting natural dispersal limitations. However, the distributions of gastropods after human transport are primarily explained by the prevailing climate and, to a smaller extent, by distance and trade relationships. Our findings show that human-mediated dispersal is causing a breakdown of biogeographic barriers, and that climate and to some extent socioeconomic relationships will define biogeography in an era of global change. PMID:26068851

  18. Global threats from invasive alien species in the twenty-first century and national response capacities.

    PubMed

    Early, Regan; Bradley, Bethany A; Dukes, Jeffrey S; Lawler, Joshua J; Olden, Julian D; Blumenthal, Dana M; Gonzalez, Patrick; Grosholz, Edwin D; Ibañez, Ines; Miller, Luke P; Sorte, Cascade J B; Tatem, Andrew J

    2016-01-01

    Invasive alien species (IAS) threaten human livelihoods and biodiversity globally. Increasing globalization facilitates IAS arrival, and environmental changes, including climate change, facilitate IAS establishment. Here we provide the first global, spatial analysis of the terrestrial threat from IAS in light of twenty-first century globalization and environmental change, and evaluate national capacities to prevent and manage species invasions. We find that one-sixth of the global land surface is highly vulnerable to invasion, including substantial areas in developing economies and biodiversity hotspots. The dominant invasion vectors differ between high-income countries (imports, particularly of plants and pets) and low-income countries (air travel). Uniting data on the causes of introduction and establishment can improve early-warning and eradication schemes. Most countries have limited capacity to act against invasions. In particular, we reveal a clear need for proactive invasion strategies in areas with high poverty levels, high biodiversity and low historical levels of invasion. PMID:27549569

  19. Global threats from invasive alien species in the twenty-first century and national response capacities

    PubMed Central

    Early, Regan; Bradley, Bethany A.; Dukes, Jeffrey S.; Lawler, Joshua J.; Olden, Julian D.; Blumenthal, Dana M.; Gonzalez, Patrick; Grosholz, Edwin D.; Ibañez, Ines; Miller, Luke P.; Sorte, Cascade J. B.; Tatem, Andrew J.

    2016-01-01

    Invasive alien species (IAS) threaten human livelihoods and biodiversity globally. Increasing globalization facilitates IAS arrival, and environmental changes, including climate change, facilitate IAS establishment. Here we provide the first global, spatial analysis of the terrestrial threat from IAS in light of twenty-first century globalization and environmental change, and evaluate national capacities to prevent and manage species invasions. We find that one-sixth of the global land surface is highly vulnerable to invasion, including substantial areas in developing economies and biodiversity hotspots. The dominant invasion vectors differ between high-income countries (imports, particularly of plants and pets) and low-income countries (air travel). Uniting data on the causes of introduction and establishment can improve early-warning and eradication schemes. Most countries have limited capacity to act against invasions. In particular, we reveal a clear need for proactive invasion strategies in areas with high poverty levels, high biodiversity and low historical levels of invasion. PMID:27549569

  20. Inferring optimal species trees under gene duplication and loss.

    PubMed

    Bayzid, M S; Mirarab, S; Warnow, T

    2013-01-01

    Species tree estimation from multiple markers is complicated by the fact that gene trees can differ from each other (and from the true species tree) due to several biological processes, one of which is gene duplication and loss. Local search heuristics for two NP-hard optimization problems - minimize gene duplications (MGD) and minimize gene duplications and losses (MGDL) - are popular techniques for estimating species trees in the presence of gene duplication and loss. In this paper, we present an alternative approach to solving MGD and MGDL from rooted gene trees. First, we characterize each tree in terms of its "subtree-bipartitions" (a concept we introduce). Then we show that the MGD species tree is defined by a maximum weight clique in a vertex-weighted graph that can be computed from the subtree-bipartitions of the input gene trees, and the MGDL species tree is defined by a minimum weight clique in a similarly constructed graph. We also show that these optimal cliques can be found in polynomial time in the number of vertices of the graph using a dynamic programming algorithm (similar to that of Hallett and Lagergren(1)), because of the special structure of the graphs. Finally, we show that a constrained version of these problems, where the subtree-bipartitions of the species tree are drawn from the subtree-bipartitions of the input gene trees, can be solved in time that is polynomial in the number of gene trees and taxa. We have implemented our dynamic programming algorithm in a publicly available software tool, available at http://www.cs.utexas.edu/users/phylo/software/dynadup/. PMID:23424130

  1. Inconsistency of Species Tree Methods under Gene Flow.

    PubMed

    Solís-Lemus, Claudia; Yang, Mengyao; Ané, Cécile

    2016-09-01

    Coalescent-based methods are now broadly used to infer evolutionary relationships between groups of organisms under the assumption that incomplete lineage sorting (ILS) is the only source of gene tree discordance. Many of these methods are known to consistently estimate the species tree when all their assumptions are met. Nonetheless, little work has been done to test the robustness of such methods to violations of their assumptions. Here, we study the performance of two of the most efficient coalescent-based methods, ASTRAL and NJst, in the presence of gene flow. Gene flow violates the assumption that ILS is the sole source of gene tree conflict. We find anomalous gene trees on three-taxon rooted trees and on four-taxon unrooted trees. These anomalous trees do not exist under ILS only, but appear because of gene flow. Our simulations show that species tree methods (and concatenation) may reconstruct the wrong evolutionary history, even from a very large number of well-reconstructed gene trees. In other words, species tree methods can be inconsistent under gene flow. Our results underline the need for methods like PhyloNet, to account simultaneously for ILS and gene flow in a unified framework. Although much slower, PhyloNet had better accuracy and remained consistent at high levels of gene flow. PMID:27151419

  2. Alien species and their zoonotic parasites in native and introduced ranges: The raccoon dog example.

    PubMed

    Laurimaa, Leidi; Süld, Karmen; Davison, John; Moks, Epp; Valdmann, Harri; Saarma, Urmas

    2016-03-30

    The raccoon dog (Nyctereutes procyonoides) is a canid that is indigenous in East Asia and alien in Europe, where it was introduced more than half a century ago. The aim of this study was to compare the parasite faunas associated with raccoon dogs in their native and introduced ranges, and to identify zoonotic parasite species. We examined 255 carcasses of hunted raccoon dogs from Estonia and recorded a total of 17 helminth species: 4 trematodes, 4 cestodes and 9 nematodes. The most prevalent parasite species were Uncinaria stenocephala (97.6%) and Alaria alata (68.3%). Average parasite species richness was 2.86 (the highest was 9) and only two animals were not parasitized at all. Although the infection intensity was determined by weight and not by sex, all animals infected with more than five helminth species were males. We also found that animals infected with higher numbers of helminth species fed significantly more on natural plants. Intentional consumption of grass may represent a self-medicating behaviour among raccoon dogs. We included the Estonian data into a wider comparison of raccoon dog parasite faunas and found a total of 54 helminth taxa, including 28 of zoonotic potential. In Europe, raccoon dogs are infected with a minimum of 32 helminth species of which 19 are zoonotic; in the native range they are infected with 26 species of which 17 are zoonotic. Most species were nematodes or trematodes, with fewer cestodes described. The recent increase in the number and range of raccoon dogs in Europe and the relatively high number of zoonotic parasite taxa that it harbours suggests that this species should be considered an important source of environmental contamination with zoonotic agents in Europe. PMID:26921035

  3. Jack-of-all-trades: phenotypic plasticity facilitates the invasion of an alien slug species

    PubMed Central

    Knop, Eva; Reusser, Nik

    2012-01-01

    Invasive alien species might benefit from phenotypic plasticity by being able to (i) maintain fitness in stressful environments (‘robust’), (ii) increase fitness in favourable environments (‘opportunistic’), or (iii) combine both abilities (‘robust and opportunistic’). Here, we applied this framework, for the first time, to an animal, the invasive slug, Arion lusitanicus, and tested (i) whether it has a more adaptive phenotypic plasticity compared with a congeneric native slug, Arion fuscus, and (ii) whether it is robust, opportunistic or both. During one year, we exposed specimens of both species to a range of temperatures along an altitudinal gradient (700–2400 m a.s.l.) and to high and low food levels, and we compared the responsiveness of two fitness traits: survival and egg production. During summer, the invasive species had a more adaptive phenotypic plasticity, and at high temperatures and low food levels, it survived better and produced more eggs than A. fuscus, representing the robust phenotype. During winter, A. lusitanicus displayed a less adaptive phenotype than A. fuscus. We show that the framework developed for plants is also very useful for a better mechanistic understanding of animal invasions. Warmer summers and milder winters might lead to an expansion of this invasive species to higher altitudes and enhance its spread in the lowlands, supporting the concern that global climate change will increase biological invasions. PMID:23015630

  4. Horizon scanning for invasive alien species with the potential to threaten biodiversity in Great Britain

    PubMed Central

    Roy, Helen E; Peyton, Jodey; Aldridge, David C; Bantock, Tristan; Blackburn, Tim M; Britton, Robert; Clark, Paul; Cook, Elizabeth; Dehnen-Schmutz, Katharina; Dines, Trevor; Dobson, Michael; Edwards, François; Harrower, Colin; Harvey, Martin C; Minchin, Dan; Noble, David G; Parrott, Dave; Pocock, Michael J O; Preston, Chris D; Roy, Sugoto; Salisbury, Andrew; Schönrogge, Karsten; Sewell, Jack; Shaw, Richard H; Stebbing, Paul; Stewart, Alan J A; Walker, Kevin J

    2014-01-01

    Invasive alien species (IAS) are considered one of the greatest threats to biodiversity, particularly through their interactions with other drivers of change. Horizon scanning, the systematic examination of future potential threats and opportunities, leading to prioritization of IAS threats is seen as an essential component of IAS management. Our aim was to consider IAS that were likely to impact on native biodiversity but were not yet established in the wild in Great Britain. To achieve this, we developed an approach which coupled consensus methods (which have previously been used for collaboratively identifying priorities in other contexts) with rapid risk assessment. The process involved two distinct phases: Preliminary consultation with experts within five groups (plants, terrestrial invertebrates, freshwater invertebrates, vertebrates and marine species) to derive ranked lists of potential IAS.Consensus-building across expert groups to compile and rank the entire list of potential IAS. Five hundred and ninety-one species not native to Great Britain were considered. Ninety-three of these species were agreed to constitute at least a medium risk (based on score and consensus) with respect to them arriving, establishing and posing a threat to native biodiversity. The quagga mussel, Dreissena rostriformis bugensis, received maximum scores for risk of arrival, establishment and impact; following discussions the unanimous consensus was to rank it in the top position. A further 29 species were considered to constitute a high risk and were grouped according to their ranked risk. The remaining 63 species were considered as medium risk, and included in an unranked long list. The information collated through this novel extension of the consensus method for horizon scanning provides evidence for underpinning and prioritizing management both for the species and, perhaps more importantly, their pathways of arrival. Although our study focused on Great Britain, we suggest that

  5. Indirect interactions among tropical tree species through shared rodent seed predators: a novel mechanism of tree species coexistence.

    PubMed

    Garzon-Lopez, Carol X; Ballesteros-Mejia, Liliana; Ordoñez, Alejandro; Bohlman, Stephanie A; Olff, Han; Jansen, Patrick A

    2015-08-01

    The coexistence of numerous tree species in tropical forests is commonly explained by negative dependence of recruitment on the conspecific seed and tree density due to specialist natural enemies that attack seeds and seedlings ('Janzen-Connell' effects). Less known is whether guilds of shared seed predators can induce a negative dependence of recruitment on the density of different species of the same plant functional group. We studied 54 plots in tropical forest on Barro Colorado Island, Panama, with contrasting mature tree densities of three coexisting large seeded tree species with shared seed predators. Levels of seed predation were far better explained by incorporating seed densities of all three focal species than by conspecific seed density alone. Both positive and negative density dependencies were observed for different species combinations. Thus, indirect interactions via shared seed predators can either promote or reduce the coexistence of different plant functional groups in tropical forest. PMID:25939379

  6. Exploring the Taxonomy of Oaks and Related Tree Species

    ERIC Educational Resources Information Center

    McMaster, Robert T.

    2004-01-01

    A lab in Eastern North America conducted a study to determine the taxonomic relationship between deciduous trees and several species of oaks by calculating the similarity index of all species to be studied. The study enabled students to classify the different species of oaks according to their distinct characteristics.

  7. Mapping urban forest tree species using IKONOS imagery: preliminary results.

    PubMed

    Pu, Ruiliang

    2011-01-01

    A stepwise masking system with high-resolution IKONOS imagery was developed to identify and map urban forest tree species/groups in the City of Tampa, Florida, USA. The eight species/groups consist of sand live oak (Quercus geminata), laurel oak (Quercus laurifolia), live oak (Quercus virginiana), magnolia (Magnolia grandiflora), pine (species group), palm (species group), camphor (Cinnamomum camphora), and red maple (Acer rubrum). The system was implemented with soil-adjusted vegetation index (SAVI) threshold, textural information after running a low-pass filter, and brightness threshold of NIR band to separate tree canopies from non-vegetated areas from other vegetation types (e.g., grass/lawn) and to separate the tree canopies into sunlit and shadow areas. A maximum likelihood classifier was used to identify and map forest type and species. After IKONOS imagery was preprocessed, a total of nine spectral features were generated, including four spectral bands, three hue-intensity-saturation indices, one SAVI, and one texture image. The identified and mapped results were examined with independent ground survey data. The experimental results indicate that when classifying all the eight tree species/ groups with the high-resolution IKONOS image data, the identifying accuracy was very low and could not satisfy a practical application level, and when merging the eight species/groups into four major species/groups, the average accuracy is still low (average accuracy = 73%, overall accuracy = 86%, and κ = 0.76 with sunlit test samples). Such a low accuracy of identifying and mapping the urban tree species/groups is attributable to low spatial resolution IKONOS image data relative to tree crown size, to complex and variable background spectrum impact on crown spectra, and to shadow/shaded impact. The preliminary results imply that to improve the tree species identification accuracy and achieve a practical application level in urban area, multi-temporal (multi

  8. Soil nutrients influence spatial distributions of tropical tree species

    PubMed Central

    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.

    2007-01-01

    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 (<104 km2) and regional scales. At local scales (<1 km2), 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. PMID:17215353

  9. Cross-scale modelling of alien and native vascular plant species richness in Great Britain: where is geodiversity information most relevant?

    NASA Astrophysics Data System (ADS)

    Bailey, Joseph; Field, Richard; Boyd, Doreen

    2016-04-01

    We assess the scale-dependency of the relationship between biodiversity and novel geodiversity information by studying spatial patterns of native and alien (archaeophytes and neophytes) vascular plant species richness at varying spatial scales across Great Britain. Instead of using a compound geodiversity metric, we study individual geodiversity components (GDCs) to advance our understanding of which aspects of 'geodiversity' are most important and at what scale. Terrestrial native (n = 1,490) and alien (n = 1,331) vascular plant species richness was modelled across the island of Great Britain at two grain sizes and several extent radii. Various GDCs (landforms, hydrology, geology) were compiled from existing national datasets and automatically extracted landform coverage information (e.g. hollows, valleys, peaks), the latter using a digital elevation model (DEM) and geomorphometric techniques. More traditional predictors of species richness (climate, widely-used topography metrics, land cover diversity, and human population) were also incorporated. Boosted Regression Tree (BRT) models were produced at all grain sizes and extents for each species group and the dominant predictors were assessed. Models with and without geodiversity data were compared. Overarching patterns indicated a clear dominance of geodiversity information at the smallest study extent (12.5km radius) and finest grain size (1x1km), which substantially decreased for each increase in extent as the contribution of climatic variables increased. The contribution of GDCs to biodiversity models was chiefly driven by landform information from geomorphometry, but hydrology (rivers and lakes), and to a lesser extent materials (soil, superficial deposits, and geology), were important, also. GDCs added significantly to vascular plant biodiversity models in Great Britain, independently of widely-used topographic metrics, particularly for native species. The wider consideration of geodiversity alongside

  10. Contrasting impacts of climate-driven flowering phenology on changes in alien and native plant species distributions.

    PubMed

    Hulme, Philip E

    2011-01-01

    • Plant phenology is particularly sensitive to climate and a key indicator of environmental change. Globally, first flowering dates (FFDs) have advanced by several days per decade in response to recent climate warming, but, while earlier flowering should allow plant distributions to increase, a link between FFD and range changes has not been observed. • Here I show for 347 species that the extent to which FFD has responded to climate warming is linked to the degree to which their relative distributions have changed over 30 yr across the British Isles. • Native plant species whose phenology did not track climate change declined in distribution, whereas species that became more widespread all exhibited earlier flowering. In contrast, alien neophytes showed both a stronger phenological response to warming and a more marked increase in distribution, but no link between the two. • These trends were consistent both for relative changes in the national distribution and for local abundance. At the national scale, the more recently an alien species became established in Britain, the more likely it was to increase in distribution irrespective of FFD, suggesting that recent changes in alien species distributions are decoupled from climate and driven by other factors. PMID:20807339

  11. Tree Species Classification By Multiseasonal High Resolution Satellite Data

    NASA Astrophysics Data System (ADS)

    Elatawneh, Alata; Wallner, Adelheid; Straub, Christoph; Schneider, Thomas; Knoke, Thomas

    2013-12-01

    Accurate forest tree species mapping is a fundamental issue for sustainable forest management and planning. Forest tree species mapping with the means of remote sensing data is still a topic to be investigated. The Bavaria state institute of forestry is investigating the potential of using digital aerial images for forest management purposes. However, using aerial images is still cost- and time-consuming, in addition to their acquisition restrictions. The new space-born sensor generations such as, RapidEye, with a very high temporal resolution, offering multiseasonal data have the potential to improve the forest tree species mapping. In this study, we investigated the potential of multiseasonal RapidEye data for mapping tree species in a Mid European forest in Southern Germany. The RapidEye data of level A3 were collected on ten different dates in the years 2009, 2010 and 2011. For data analysis, a model was developed, which combines the Spectral Angle Mapper technique with a 10-fold- cross-validation. The analysis succeeded to differentiate four tree species; Norway spruce (Picea abies L.), Silver Fir (Abies alba Mill.), European beech (Fagus sylvatica) and Maple (Acer pseudoplatanus). The model success was evaluated using digital aerial images acquired in the year 2009 and inventory point records from 2008/09 inventory. Model results of the multiseasonal RapidEye data analysis achieved an overall accuracy of 76%. However, the success of the model was evaluated only for all the identified species and not for the individual.

  12. 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.

  13. Widespread Discordance of Gene Trees with Species Tree in Drosophila: Evidence for Incomplete Lineage Sorting

    PubMed Central

    Pollard, Daniel A; Eisen, Michael B

    2006-01-01

    The phylogenetic relationship of the now fully sequenced species Drosophila erecta and D. yakuba with respect to the D. melanogaster species complex has been a subject of controversy. All three possible groupings of the species have been reported in the past, though recent multi-gene studies suggest that D. erecta and D. yakuba are sister species. Using the whole genomes of each of these species as well as the four other fully sequenced species in the subgenus Sophophora, we set out to investigate the placement of D. erecta and D. yakuba in the D. melanogaster species group and to understand the cause of the past incongruence. Though we find that the phylogeny grouping D. erecta and D. yakuba together is the best supported, we also find widespread incongruence in nucleotide and amino acid substitutions, insertions and deletions, and gene trees. The time inferred to span the two key speciation events is short enough that under the coalescent model, the incongruence could be the result of incomplete lineage sorting. Consistent with the lineage-sorting hypothesis, substitutions supporting the same tree were spatially clustered. Support for the different trees was found to be linked to recombination such that adjacent genes support the same tree most often in regions of low recombination and substitutions supporting the same tree are most enriched roughly on the same scale as linkage disequilibrium, also consistent with lineage sorting. The incongruence was found to be statistically significant and robust to model and species choice. No systematic biases were found. We conclude that phylogenetic incongruence in the D. melanogaster species complex is the result, at least in part, of incomplete lineage sorting. Incomplete lineage sorting will likely cause phylogenetic incongruence in many comparative genomics datasets. Methods to infer the correct species tree, the history of every base in the genome, and comparative methods that control for and/or utilize this

  14. Analyzing the Social Factors That Influence Willingness to Pay for Invasive Alien Species Management Under Two Different Strategies: Eradication and Prevention

    NASA Astrophysics Data System (ADS)

    García-Llorente, Marina; Martín-López, Berta; Nunes, Paulo A. L. D.; González, José A.; Alcorlo, Paloma; Montes, Carlos

    2011-09-01

    Biological invasions occur worldwide, and have been the object of ecological and socio-economic research for decades. However, the manner in which different stakeholder groups identify the problems associated with invasive species and confront invasive species management under different policies remains poorly understood. In this study, we conducted an econometric analysis of the social factors influencing willingness to pay for invasive alien species management under two different regimes: eradication and prevention in the Doñana Natural Protected Area (SW Spain). Controlling for the participation of local residents, tourists and conservationists, email and face-to-face questionnaires were conducted. Results indicated that respondents were more willing to pay for eradication than prevention; and public support for invasive alien species management was influenced by an individual's knowledge and perception of invasive alien species, active interest in nature, and socio-demographic attributes. We concluded that invasive alien species management research should confront the challenges to engage stakeholders and accept any tradeoffs necessary to modify different conservation policies to ensure effective management is implemented. Finally, our willingness to pay estimates suggest the Department of Environment of Andalusian Government has suitable social support to meet the budgetary expenditures required for invasive alien species plans and adequate resources to justify an increase in the invasive alien species management budget.

  15. Perception and Understanding of Invasive Alien Species Issues by Nature Conservation and Horticulture Professionals in Belgium

    NASA Astrophysics Data System (ADS)

    Vanderhoeven, Sonia; Piqueray, Julien; Halford, Mathieu; Nulens, Greet; Vincke, Jan; Mahy, Grégory

    2011-03-01

    We conducted a survey to determine how two professional sectors in Belgium, horticulture professionals and nature reserve managers (those directly involved in conservation), view the issues associated with invasive plant species. We developed and utilized a questionnaire that addressed the themes of awareness, concept and use of language, availability of information, impacts and, finally, control and available solutions. Using co-inertia analyses, we tested to what extent the perception of invasive alien species (IAS) was dependent upon the perception of Nature in general. Only forty-two percent of respondent horticulture professionals and eighty-two percent of nature reserve managers had a general knowledge of IAS. Many individuals in both target groups nonetheless had an accurate understanding of the scientific issues. Our results therefore suggest that the manner in which individuals within the two groups view, or perceive, the IAS issue was more the result of lack of information than simply biased perceptions of target groups. Though IAS perceptions by the two groups diverged, they were on par with how they viewed Nature in general. The descriptions of IAS by participants converged with the ideas and concepts frequently found in the scientific literature. Both managers and horticulture professionals expressed a strong willingness to participate in programs designed to prevent the spread of, and damage caused by, IAS. Despite this, the continued commercial availability of many invasive species highlighted the necessity to use both mandatory and voluntary approaches to reduce their re-introduction and spread. The results of this study provide stakeholders and conservation managers with practical information on which communication and management strategies can be based.

  16. Geographical Range and Local Abundance of Tree Species in China

    PubMed Central

    Ren, Haibao; Condit, Richard; Chen, Bin; Mi, Xiangcheng; Cao, Min; Ye, Wanhui; Hao, Zhanqing; Ma, Keping

    2013-01-01

    Most studies on the geographical distribution of species have utilized a few well-known taxa in Europe and North America, with little research in China and its wide range of climate and forest types. We assembled large datasets to quantify the geographic ranges of tree species in China and to test several biogeographic hypotheses: 1) whether locally abundant species tend to be geographically widespread; 2) whether species are more abundant towards their range-centers; and 3) how abundances are correlated between sites. Local abundances of 651 species were derived from four tree plots of 20–25 ha where all individuals ≥1 cm in stem diameter were mapped and identified taxonomically. Range sizes of these species across China were then estimated from over 460,000 geo-referenced records; a Bayesian approach was used, allowing careful measures of error of each range estimate. The log-transformed range sizes had a bell-shaped distribution with a median of 703,000 km2, and >90% of 651 species had ranges >105 km2. There was no relationship between local abundance and range size, and no evidence for species being more abundant towards their range-centers. Finally, species’ abundances were positively correlated between sites. The widespread nature of most tree species in China suggests few are vulnerable to global extinction, and there is no indication of the double-peril that would result if rare species also had narrow ranges. PMID:24130772

  17. Why abundant tropical tree species are phylogenetically old.

    PubMed

    Wang, Shaopeng; Chen, Anping; Fang, Jingyun; Pacala, Stephen W

    2013-10-01

    Neutral models of species diversity predict patterns of abundance for communities in which all individuals are ecologically equivalent. These models were originally developed for Panamanian trees and successfully reproduce observed distributions of abundance. Neutral models also make macroevolutionary predictions that have rarely been evaluated or tested. Here we show that neutral models predict a humped or flat relationship between species age and population size. In contrast, ages and abundances of tree species in the Panamanian Canal watershed are found to be positively correlated, which falsifies the models. Speciation rates vary among phylogenetic lineages and are partially heritable from mother to daughter species. Variable speciation rates in an otherwise neutral model lead to a demographic advantage for species with low speciation rate. This demographic advantage results in a positive correlation between species age and abundance, as found in the Panamanian tropical forest community. PMID:24043767

  18. Ecological impacts of invasive alien species along temperature gradients: testing the role of environmental matching.

    PubMed

    Iacarella, Josephine C; Dick, Jaimie T A; Alexander, Mhairi E; Ricciardi, Anthony

    2015-04-01

    Invasive alien species (IAS) can cause substantive ecological impacts, and the role of temperature in mediating these impacts may become increasingly significant in a changing climate. Habitat conditions and physiological optima offer predictive information for IAS impacts in novel environments. Here, using meta-analysis and laboratory experiments, we tested the hypothesis that the impacts of IAS in the field are inversely correlated with the difference in their ambient and optimal temperatures. A meta-analysis of 29 studies of consumptive impacts of IAS in inland waters revealed that the impacts of fishes and crustaceans are higher at temperatures that more closely match their thermal growth optima. In particular, the maximum impact potential was constrained by increased differences between ambient and optimal temperatures, as indicated by the steeper slope of a quantile regression on the upper 25th percentile of impact data compared to that of a weighted linear regression on all data with measured variances. We complemented this study with an experimental analysis of the functional response (the relationship between predation rate and prey supply) of two invasive predators (freshwater mysid shrimp, Hemimysis anomala and Mysis diluviana) across. relevant temperature gradients; both of these species have previously been found to exert strong community-level impacts that are corroborated by their functional responses to different prey items. The functional response experiments showed that maximum feeding rates of H. anomala and M. diluviana have distinct peaks near their respective thermal optima. Although variation in impacts may be caused by numerous abiotic or biotic habitat characteristics, both our analyses point to temperature as a key mediator of IAS impact levels in inland waters and suggest that IAS management should prioritize habitats in the invaded range that more closely match the thermal optima of targeted invaders. PMID:26214916

  19. Is tree species diversity or tree species identity the most important driver of European forest soil carbon stocks?

    NASA Astrophysics Data System (ADS)

    Vesterdal, Lars; Muhie Dawud, Seid; Raulund-Rasmussen, Karsten; Finér, Leena; Domisch, Timo

    2016-04-01

    Land management includes the selection of specific tree species and tree species mixtures for European forests. Studies of functional species diversity effects have reported positive effects for aboveground carbon (C) sequestration, but the question remains whether higher soil C stocks could also result from belowground niche differentiation including more efficient root exploitation of soils. We studied topsoil C stocks in tree species diversity gradients established within the FunDivEurope project to explore biodiversity-ecosystem functioning relationships in six European forest types in Finland, Poland, Germany, Romania, Spain and Italy. In the Polish forest type we extended the sampling to also include subsoils. We found consistent but modest effects of species diversity on total soil C stocks (forest floor and 0-20 cm) across the six European forest types. Carbon stocks in the forest floor alone and in the combined forest floor and mineral soil layers increased with increasing tree species diversity. In contrast, there was a strong effect of species identity (broadleaf vs. conifer) and its interaction with site-related factors. Within the Polish forest type we sampled soils down to 40 cm and found that species identity was again the main factor explaining total soil C stock. However, species diversity increased soil C stocks in deeper soil layers (20-40 cm), while species identity influenced C stocks significantly within forest floors and the 0-10 cm layer. Root biomass increased with diversity in 30-40 cm depth, and a positive relationship between C stocks and root biomass in the 30-40 cm layer suggested that belowground niche complementarity could be a driving mechanism for higher root carbon input and in turn a deeper distribution of C in diverse forests. We conclude that total C stocks are mainly driven by tree species identity. However, modest positive diversity effects were detected at the European scale, and stronger positive effects on subsoil C stocks

  20. Preliminary Genomic Characterization of Ten Hardwood Tree Species from Multiplexed Low Coverage Whole Genome Sequencing

    PubMed Central

    Staton, Margaret; Best, Teodora; Khodwekar, Sudhir; Owusu, Sandra; Xu, Tao; Xu, Yi; Jennings, Tara; Cronn, Richard; Arumuganathan, A. Kathiravetpilla; Coggeshall, Mark; Gailing, Oliver; Liang, Haiying; Romero-Severson, Jeanne; Schlarbaum, Scott; Carlson, John E.

    2015-01-01

    Forest health issues are on the rise in the United States, resulting from introduction of alien pests and diseases, coupled with abiotic stresses related to climate change. Increasingly, forest scientists are finding genetic/genomic resources valuable in addressing forest health issues. For a set of ten ecologically and economically important native hardwood tree species representing a broad phylogenetic spectrum, we used low coverage whole genome sequencing from multiplex Illumina paired ends to economically profile their genomic content. For six species, the genome content was further analyzed by flow cytometry in order to determine the nuclear genome size. Sequencing yielded a depth of 0.8X to 7.5X, from which in silico analysis yielded preliminary estimates of gene and repetitive sequence content in the genome for each species. Thousands of genomic SSRs were identified, with a clear predisposition toward dinucleotide repeats and AT-rich repeat motifs. Flanking primers were designed for SSR loci for all ten species, ranging from 891 loci in sugar maple to 18,167 in redbay. In summary, we have demonstrated that useful preliminary genome information including repeat content, gene content and useful SSR markers can be obtained at low cost and time input from a single lane of Illumina multiplex sequence. PMID:26698853

  1. Multilocus inference of species trees and DNA barcoding.

    PubMed

    Mallo, Diego; Posada, David

    2016-09-01

    The unprecedented amount of data resulting from next-generation sequencing has opened a new era in phylogenetic estimation. Although large datasets should, in theory, increase phylogenetic resolution, massive, multilocus datasets have uncovered a great deal of phylogenetic incongruence among different genomic regions, due both to stochastic error and to the action of different evolutionary process such as incomplete lineage sorting, gene duplication and loss and horizontal gene transfer. This incongruence violates one of the fundamental assumptions of the DNA barcoding approach, which assumes that gene history and species history are identical. In this review, we explain some of the most important challenges we will have to face to reconstruct the history of species, and the advantages and disadvantages of different strategies for the phylogenetic analysis of multilocus data. In particular, we describe the evolutionary events that can generate species tree-gene tree discordance, compare the most popular methods for species tree reconstruction, highlight the challenges we need to face when using them and discuss their potential utility in barcoding. Current barcoding methods sacrifice a great amount of statistical power by only considering one locus, and a transition to multilocus barcodes would not only improve current barcoding methods, but also facilitate an eventual transition to species-tree-based barcoding strategies, which could better accommodate scenarios where the barcode gap is too small or inexistent.This article is part of the themed issue 'From DNA barcodes to biomes'. PMID:27481787

  2. The amathiiform Ctenostomata (phylum Bryozoa) of New Zealand--including four new species, two of them of probable alien origin.

    PubMed

    Gordon, Dennis P; Spencer-Jones, Mary

    2013-01-01

    The status of the vesiculariid ctenostome genus Amathia in New Zealand has been evaluated on the basis of all known material, including historic specimens in museums and those newly collected during formal surveillance of ports, harbours and vessels for possible alien species. Eight species are recognised, four of them new to science. Amathia gracei n. sp. and Amathia zealandica n. sp. are the only apparently endemic species. Amathia chimonidesi n. sp. appears to be a previously unrecognised alien species and is known only from shipping harbours and/or yacht marinas and some nearby beaches. Amathia similis n. sp. has been known in the Auckland area since the 1960s but was confused with A. distans Busk. Amathia bicornis (Tenison-Woods), A. biseriata Krauss, A. lamourouxi Chimonides and A. wilsoni Kirkpatrick are Australasian species that occur naturally on both sides of the Tasman Sea. Of this latter group, A. bicornis was discovered only at a single locality on the southwest coast of North Island in 1983 on a fucoid seaweed and it may be relatively re-cently self-introduced. A specimen of A. lendigera (Linnaeus) in the Museum of New Zealand, purportedly from Napier, is considered to be based on a misunderstanding or a labelling error and does not represent a failed alien introduction. The Amathia-like vesiculariid Bowerbankia citrina (Hincks) sensu lato is newly recorded for New Zealand. Keys are provided to the amathiiform (i.e. Amathia and Amathia-like) Ctenostomata of New Zealand and to the worldwide species of Amathia and Bowerbankia with zooid clusters spiralled on stoloniform axes. PMID:26295099

  3. tropiTree: an NGS-based EST-SSR resource for 24 tropical tree species.

    PubMed

    Russell, Joanne R; Hedley, Peter E; Cardle, Linda; Dancey, Siobhan; Morris, Jenny; Booth, Allan; Odee, David; Mwaura, Lucy; Omondi, William; Angaine, Peter; Machua, Joseph; Muchugi, Alice; Milne, Iain; Kindt, Roeland; Jamnadass, Ramni; Dawson, Ian K

    2014-01-01

    The development of genetic tools for non-model organisms has been hampered by cost, but advances in next-generation sequencing (NGS) have created new opportunities. In ecological research, this raises the prospect for developing molecular markers to simultaneously study important genetic processes such as gene flow in multiple non-model plant species within complex natural and anthropogenic landscapes. Here, we report the use of bar-coded multiplexed paired-end Illumina NGS for the de novo development of expressed sequence tag-derived simple sequence repeat (EST-SSR) markers at low cost for a range of 24 tree species. Each chosen tree species is important in complex tropical agroforestry systems where little is currently known about many genetic processes. An average of more than 5,000 EST-SSRs was identified for each of the 24 sequenced species, whereas prior to analysis 20 of the species had fewer than 100 nucleotide sequence citations. To make results available to potential users in a suitable format, we have developed an open-access, interactive online database, tropiTree (http://bioinf.hutton.ac.uk/tropiTree), which has a range of visualisation and search facilities, and which is a model for the efficient presentation and application of NGS data. PMID:25025376

  4. tropiTree: An NGS-Based EST-SSR Resource for 24 Tropical Tree Species

    PubMed Central

    Russell, Joanne R.; Hedley, Peter E.; Cardle, Linda; Dancey, Siobhan; Morris, Jenny; Booth, Allan; Odee, David; Mwaura, Lucy; Omondi, William; Angaine, Peter; Machua, Joseph; Muchugi, Alice; Milne, Iain; Kindt, Roeland; Jamnadass, Ramni; Dawson, Ian K.

    2014-01-01

    The development of genetic tools for non-model organisms has been hampered by cost, but advances in next-generation sequencing (NGS) have created new opportunities. In ecological research, this raises the prospect for developing molecular markers to simultaneously study important genetic processes such as gene flow in multiple non-model plant species within complex natural and anthropogenic landscapes. Here, we report the use of bar-coded multiplexed paired-end Illumina NGS for the de novo development of expressed sequence tag-derived simple sequence repeat (EST-SSR) markers at low cost for a range of 24 tree species. Each chosen tree species is important in complex tropical agroforestry systems where little is currently known about many genetic processes. An average of more than 5,000 EST-SSRs was identified for each of the 24 sequenced species, whereas prior to analysis 20 of the species had fewer than 100 nucleotide sequence citations. To make results available to potential users in a suitable format, we have developed an open-access, interactive online database, tropiTree (http://bioinf.hutton.ac.uk/tropiTree), which has a range of visualisation and search facilities, and which is a model for the efficient presentation and application of NGS data. PMID:25025376

  5. Gene trees versus species trees: reassessing life-history evolution in a freshwater fish radiation.

    PubMed

    Waters, Jonathan M; Rowe, Diane L; Burridge, Christopher P; Wallis, Graham P

    2010-10-01

    Mechanisms of speciation are best understood in the context of phylogenetic relationships and as such have often been inferred from single gene trees, typically those derived from mitochondrial DNA (mtDNA) markers. Recent studies, however, have noted the potential for phylogenetic discordance between gene trees and underlying species trees (e.g., due to stochastic lineage sorting, introgression, or selection). Here, we employ a variety of nuclear DNA loci to reassess evolutionary relationships within a recent freshwater fish radiation to reappraise modes of speciation. New Zealand's freshwater-limited Galaxias vulgaris complex is thought to have evolved from G. brevipinnis, a widespread migratory species that retains a plesiomorphic marine juvenile phase. A well-resolved tree, based on four mtDNA regions, previously suggested that marine migratory ability has been lost on 3 independent occasions in the evolution of this species flock (assuming that loss of diadromy is irreversible). Here, we use pseudogene (galaxiid Numt: 1801 bp), intron (S: 903 bp), and exon (RAG-1: 1427 bp) markers, together with mtDNA, to reevaluate this hypothesis of parallel evolution. Interestingly, partitioned Bayesian analysis of concatenated nuclear sequences (3141 bp) and concatenated nuclear and mtDNA (4770 bp) both recover phylogenies implying a single loss of diadromy, not three parallel losses as previously inferred from mtDNA alone. This phylogenetic result is reinforced by a multilocus analysis performed using Bayesian estimation of species trees (BEST) software that estimates the posterior distribution of species trees under a coalescent model. We discuss factors that might explain the apparently misleading phylogenetic inferences generated by mtDNA. PMID:20603441

  6. Nitrogen Addition Enhances Drought Sensitivity of Young Deciduous Tree Species

    PubMed Central

    Dziedek, Christoph; Härdtle, Werner; von Oheimb, Goddert; Fichtner, Andreas

    2016-01-01

    Understanding how trees respond to global change drivers is central to predict changes in forest structure and functions. Although there is evidence on the mode of nitrogen (N) and drought (D) effects on tree growth, our understanding of the interplay of these factors is still limited. Simultaneously, as mixtures are expected to be less sensitive to global change as compared to monocultures, we aimed to investigate the combined effects of N addition and D on the productivity of three tree species (Fagus sylvatica, Quercus petraea, Pseudotsuga menziesii) in relation to functional diverse species mixtures using data from a 4-year field experiment in Northwest Germany. Here we show that species mixing can mitigate the negative effects of combined N fertilization and D events, but the community response is mainly driven by the combination of certain traits rather than the tree species richness of a community. For beech, we found that negative effects of D on growth rates were amplified by N fertilization (i.e., combined treatment effects were non-additive), while for oak and fir, the simultaneous effects of N and D were additive. Beech and oak were identified as most sensitive to combined N+D effects with a strong size-dependency observed for beech, suggesting that the negative impact of N+D becomes stronger with time as beech grows larger. As a consequence, the net biodiversity effect declined at the community level, which can be mainly assigned to a distinct loss of complementarity in beech-oak mixtures. This pattern, however, was not evident in the other species-mixtures, indicating that neighborhood composition (i.e., trait combination), but not tree species richness mediated the relationship between tree diversity and treatment effects on tree growth. Our findings point to the importance of the qualitative role (‘trait portfolio’) that biodiversity play in determining resistance of diverse tree communities to environmental changes. As such, they provide

  7. Nitrogen Addition Enhances Drought Sensitivity of Young Deciduous Tree Species.

    PubMed

    Dziedek, Christoph; Härdtle, Werner; von Oheimb, Goddert; Fichtner, Andreas

    2016-01-01

    Understanding how trees respond to global change drivers is central to predict changes in forest structure and functions. Although there is evidence on the mode of nitrogen (N) and drought (D) effects on tree growth, our understanding of the interplay of these factors is still limited. Simultaneously, as mixtures are expected to be less sensitive to global change as compared to monocultures, we aimed to investigate the combined effects of N addition and D on the productivity of three tree species (Fagus sylvatica, Quercus petraea, Pseudotsuga menziesii) in relation to functional diverse species mixtures using data from a 4-year field experiment in Northwest Germany. Here we show that species mixing can mitigate the negative effects of combined N fertilization and D events, but the community response is mainly driven by the combination of certain traits rather than the tree species richness of a community. For beech, we found that negative effects of D on growth rates were amplified by N fertilization (i.e., combined treatment effects were non-additive), while for oak and fir, the simultaneous effects of N and D were additive. Beech and oak were identified as most sensitive to combined N+D effects with a strong size-dependency observed for beech, suggesting that the negative impact of N+D becomes stronger with time as beech grows larger. As a consequence, the net biodiversity effect declined at the community level, which can be mainly assigned to a distinct loss of complementarity in beech-oak mixtures. This pattern, however, was not evident in the other species-mixtures, indicating that neighborhood composition (i.e., trait combination), but not tree species richness mediated the relationship between tree diversity and treatment effects on tree growth. Our findings point to the importance of the qualitative role ('trait portfolio') that biodiversity play in determining resistance of diverse tree communities to environmental changes. As such, they provide further

  8. Early positive effects of tree species richness on herbivory in a large-scale forest biodiversity experiment influence tree growth

    PubMed Central

    Schuldt, Andreas; Bruelheide, Helge; Härdtle, Werner; Assmann, Thorsten; Li, Ying; Ma, Keping; von Oheimb, Goddert; Zhang, Jiayong

    2015-01-01

    Despite the importance of herbivory for the structure and functioning of species-rich forests, little is known about how herbivory is affected by tree species richness, and more specifically by random vs. non-random species loss. We assessed herbivore damage and its effects on tree growth in the early stage of a large-scale forest biodiversity experiment in subtropical China that features random and non-random extinction scenarios of tree mixtures numbering between one and 24 species. In contrast to random species loss, the non-random extinction scenarios were based on the tree species’ local rarity and specific leaf area – traits that may strongly influence the way herbivory is affected by plant species richness. Herbivory increased with tree species richness across all scenarios and was unaffected by the different species compositions in the random and non-random extinction scenarios. Whereas tree growth rates were positively related to herbivory on plots with smaller trees, growth rates significantly declined with increasing herbivory on plots with larger trees. Our results suggest that the effects of herbivory on growth rates increase from monocultures to the most species-rich plant communities and that negative effects with increasing tree species richness become more pronounced with time as trees grow larger. Synthesis. Our results indicate that key trophic interactions can be quick to become established in forest plantations (i.e. already 2.5 years after tree planting). Stronger herbivory effects on tree growth with increasing tree species richness suggest a potentially important role of herbivory in regulating ecosystem functions and the structural development of species-rich forests from the very start of secondary forest succession. The lack of significant differences between the extinction scenarios, however, contrasts with findings from natural forests of higher successional age, where rarity had negative effects on herbivory. This indicates that

  9. Spatial distribution and temporal trends of soft-bottom marine benthic alien species collected during the period 1989-2008 in the Nervión estuary (southeastern Bay of Biscay)

    NASA Astrophysics Data System (ADS)

    Zorita, Izaskun; Solaun, Oihana; Borja, Angel; Franco, Javier; Muxika, Iñigo; Pascual, Marta

    2013-10-01

    As the introduction of alien species represents one of the most important causes of biodiversity loss, it is crucial to study the distribution of alien species in order to control or eradicate their introduction and spread. Thus, the present study aimed to analyse the spatial distribution and temporal trends of soft-bottom marine benthic alien species collected during 20 years in the Nervión estuary, southeastern Bay of Biscay. Results indicated that, from a total of 6688 species records, 117 corresponded to alien species. Likewise, from a total of 742 different species identified, 23 species were classified as alien species. The two most frequently recorded alien species, Pseudopolydora paucibranchiata and Monocorophium acherusicum, appeared mainly at the intermediate part of the estuary that suffered historically an intense pollution. The presence and abundance of soft-bottom alien species became more evident since the mid-nineties, when the widening of the Bilbao Harbour occurred, together with a water quality improvement and the industry decline. Finally, although the identified alien species are considered as not invasive, the spread of alien species in the estuary might be considered as a threat.

  10. Multilocus inference of species trees and DNA barcoding

    PubMed Central

    2016-01-01

    The unprecedented amount of data resulting from next-generation sequencing has opened a new era in phylogenetic estimation. Although large datasets should, in theory, increase phylogenetic resolution, massive, multilocus datasets have uncovered a great deal of phylogenetic incongruence among different genomic regions, due both to stochastic error and to the action of different evolutionary process such as incomplete lineage sorting, gene duplication and loss and horizontal gene transfer. This incongruence violates one of the fundamental assumptions of the DNA barcoding approach, which assumes that gene history and species history are identical. In this review, we explain some of the most important challenges we will have to face to reconstruct the history of species, and the advantages and disadvantages of different strategies for the phylogenetic analysis of multilocus data. In particular, we describe the evolutionary events that can generate species tree—gene tree discordance, compare the most popular methods for species tree reconstruction, highlight the challenges we need to face when using them and discuss their potential utility in barcoding. Current barcoding methods sacrifice a great amount of statistical power by only considering one locus, and a transition to multilocus barcodes would not only improve current barcoding methods, but also facilitate an eventual transition to species-tree-based barcoding strategies, which could better accommodate scenarios where the barcode gap is too small or inexistent. This article is part of the themed issue ‘From DNA barcodes to biomes’. PMID:27481787

  11. Impact of gene family evolutionary histories on phylogenetic species tree inference by gene tree parsimony.

    PubMed

    Shi, Tao

    2016-03-01

    Complicated history of gene duplication and loss brings challenge to molecular phylogenetic inference, especially in deep phylogenies. However, phylogenomic approaches, such as gene tree parsimony (GTP), show advantage over some other approaches in its ability to use gene families with duplications. GTP searches the 'optimal' species tree by minimizing the total cost of biological events such as duplications, but accuracy of GTP and phylogenetic signal in the context of different gene families with distinct histories of duplication and loss are unclear. To evaluate how different evolutionary properties of different gene families can impact on species tree inference, 3900 gene families from seven angiosperms encompassing a wide range of gene content, lineage-specific expansions and contractions were analyzed. It was found that the gene content and total duplication number in a gene family strongly influence species tree inference accuracy, with the highest accuracy achieved at either very low or very high gene content (or duplication number) and lowest accuracy centered in intermediate gene content (or duplication number), as the relationship can fit a binomial regression. Besides, for gene families of similar level of average gene content, those with relatively higher lineage-specific expansion or duplication rates tend to show lower accuracy. Additional correlation tests support that high accuracy for those gene families with large gene content may rely on abundant ancestral copies to provide many subtrees to resolve conflicts, whereas high accuracy for single or low copy gene families are just subject to sequence substitution per se. Very low accuracy reached by gene families of intermediate gene content or duplication number can be due to insufficient subtrees to resolve the conflicts from loss of alternative copies. As these evolutionary properties can significantly influence species tree accuracy, I discussed the potential weighting of the duplication cost by

  12. Widespread Discordance of Gene Trees with Species Tree inDrosophila: Evidence for Incomplete Lineage Sorting

    SciTech Connect

    Pollard, Daniel A.; Iyer, Venky N.; Moses, Alan M.; Eisen,Michael B.

    2006-08-28

    The phylogenetic relationship of the now fully sequencedspecies Drosophila erecta and D. yakuba with respect to the D.melanogaster species complex has been a subject of controversy. All threepossible groupings of the species have been reported in the past, thoughrecent multi-gene studies suggest that D. erecta and D. yakuba are sisterspecies. Using the whole genomes of each of these species as well as thefour other fully sequenced species in the subgenus Sophophora, we set outto investigate the placement of D. erecta and D. yakuba in the D.melanogaster species group and to understand the cause of the pastincongruence. Though we find that the phylogeny grouping D. erecta and D.yakuba together is the best supported, we also find widespreadincongruence in nucleotide and amino acid substitutions, insertions anddeletions, and gene trees. The time inferred to span the two keyspeciation events is short enough that under the coalescent model, theincongruence could be the result of incomplete lineage sorting.Consistent with the lineage-sorting hypothesis, substitutions supportingthe same tree were spatially clustered. Support for the different treeswas found to be linked to recombination such that adjacent genes supportthe same tree most often in regions of low recombination andsubstitutions supporting the same tree are most enriched roughly on thesame scale as linkage disequilibrium, also consistent with lineagesorting. The incongruence was found to be statistically significant androbust to model and species choice. No systematic biases were found. Weconclude that phylogenetic incongruence in the D. melanogaster speciescomplex is the result, at least in part, of incomplete lineage sorting.Incomplete lineage sorting will likely cause phylogenetic incongruence inmany comparative genomics datasets. Methods to infer the correct speciestree, the history of every base in the genome, and comparative methodsthat control for and/or utilize this information will be

  13. A multigene species tree for Western Mediterranean painted frogs (Discoglossus).

    PubMed

    Pabijan, Maciej; Crottini, Angelica; Reckwell, Dennis; Irisarri, Iker; Hauswaldt, J Susanne; Vences, Miguel

    2012-09-01

    Painted frogs (Discoglossus) are an anuran clade that originated in the Upper Miocene. Extant species are morphologically similar and have a circum-Mediterranean distribution. We assembled a multilocus dataset from seven nuclear and four mitochondrial genes for several individuals of all but one of the extant species and reconstructed a robust phylogeny by applying a coalescent-based species-tree method and a concatenation approach, both of which gave congruent results. The earliest phylogenetic split within Discoglossus separates D. montalentii from a clade comprising all other species. Discoglossus montalentii is monophyletic for haplotype variation at all loci and has distinct morphological, bioacoustic and karyotypic characters. We find moderate support for a sister-group relationship between the Iberian taxa and the Moroccan D. scovazzi, and high support for a D. pictus -D. sardus clade distributed around the Tyrrhenian basin. Topological discordance among gene trees during the speciation of D. galganoi, D. scovazzi, D. pictus and D. sardus is interpreted as the consequence of nearly simultaneous, vicariant diversification. The timing of these events is unclear, but possibly coincided with the final geotectonic rearrangement of the Western Mediterranean in the Middle Miocene or later during the Messinian salinity crisis. The Iberian taxa D. galganoi galganoi and D. g. jeanneae are reciprocally monophyletic in mitochondrial DNA but not in nuclear gene trees, and are therefore treated as subspecies of D. galganoi. PMID:22641173

  14. Diversification rates and species richness across the Tree of Life.

    PubMed

    Scholl, Joshua P; Wiens, John J

    2016-09-14

    Species richness varies dramatically among clades across the Tree of Life, by over a million-fold in some cases (e.g. placozoans versus arthropods). Two major explanations for differences in richness among clades are the clade-age hypothesis (i.e. species-rich clades are older) and the diversification-rate hypothesis (i.e. species-rich clades diversify more rapidly, where diversification rate is the net balance of speciation and extinction over time). Here, we examine patterns of variation in diversification rates across the Tree of Life. We address how rates vary across higher taxa, whether rates within higher taxa are related to the subclades within them, and how diversification rates of clades are related to their species richness. We find substantial variation in diversification rates, with rates in plants nearly twice as high as in animals, and rates in some eukaryotes approximately 10-fold faster than prokaryotes. Rates for each kingdom-level clade are then significantly related to the subclades within them. Although caution is needed when interpreting relationships between diversification rates and richness, a positive relationship between the two is not inevitable. We find that variation in diversification rates seems to explain most variation in richness among clades across the Tree of Life, in contrast to the conclusions of previous studies. PMID:27605507

  15. Climatic extremes improve predictions of spatial patterns of tree species

    USGS Publications Warehouse

    Zimmermann, N.E.; Yoccoz, N.G.; Edwards, T.C., Jr.; Meier, E.S.; Thuiller, W.; Guisan, A.; Schmatz, D.R.; Pearman, P.B.

    2009-01-01

    Understanding niche evolution, dynamics, and the response of species to climate change requires knowledge of the determinants of the environmental niche and species range limits. Mean values of climatic variables are often used in such analyses. In contrast, the increasing frequency of climate extremes suggests the importance of understanding their additional influence on range limits. Here, we assess how measures representing climate extremes (i.e., interannual variability in climate parameters) explain and predict spatial patterns of 11 tree species in Switzerland. We find clear, although comparably small, improvement (+20% in adjusted D2, +8% and +3% in cross-validated True Skill Statistic and area under the receiver operating characteristics curve values) in models that use measures of extremes in addition to means. The primary effect of including information on climate extremes is a correction of local overprediction and underprediction. Our results demonstrate that measures of climate extremes are important for understanding the climatic limits of tree species and assessing species niche characteristics. The inclusion of climate variability likely will improve models of species range limits under future conditions, where changes in mean climate and increased variability are expected.

  16. Thermal pollution and settlement of new tropical alien species: The case of Grateloupia yinggehaiensis (Rhodophyta) in the Venice Lagoon

    NASA Astrophysics Data System (ADS)

    Wolf, M. A.; Sfriso, A.; Moro, I.

    2014-06-01

    The Venice Lagoon has become increasingly affected by the introduction of allochthonous macroalgae mainly coming from the Indo-Pacific area. In consequence to the recent climate changes and temperature increase, such species could simply find numerous habitats suitable for their growth. One local process that contributes to water temperature changes is thermal pollution. In this study we used the DNA barcoding method to identify a new alien macroalgal species, Grateloupia yinggehaiensis Wang et Luan (Rhodophyta), found near the industrial area of Porto Marghera (Venice, Italy) hosting the Fusina thermoelectric power plant. The microclimate of this area has enabled the spread of this species native of the tropical area of the Hainan Province (China) and probably introduced in the Mediterranean Sea via shellfish transfers.

  17. Semi-supervised SVM for individual tree crown species classification

    NASA Astrophysics Data System (ADS)

    Dalponte, Michele; Ene, Liviu Theodor; Marconcini, Mattia; Gobakken, Terje; Næsset, Erik

    2015-12-01

    In this paper a novel semi-supervised SVM classifier is presented, specifically developed for tree species classification at individual tree crown (ITC) level. In ITC tree species classification, all the pixels belonging to an ITC should have the same label. This assumption is used in the learning of the proposed semi-supervised SVM classifier (ITC-S3VM). This method exploits the information contained in the unlabeled ITC samples in order to improve the classification accuracy of a standard SVM. The ITC-S3VM method can be easily implemented using freely available software libraries. The datasets used in this study include hyperspectral imagery and laser scanning data acquired over two boreal forest areas characterized by the presence of three information classes (Pine, Spruce, and Broadleaves). The experimental results quantify the effectiveness of the proposed approach, which provides classification accuracies significantly higher (from 2% to above 27%) than those obtained by the standard supervised SVM and by a state-of-the-art semi-supervised SVM (S3VM). Particularly, by reducing the number of training samples (i.e. from 100% to 25%, and from 100% to 5% for the two datasets, respectively) the proposed method still exhibits results comparable to the ones of a supervised SVM trained with the full available training set. This property of the method makes it particularly suitable for practical forest inventory applications in which collection of in situ information can be very expensive both in terms of cost and time.

  18. Inferring Species Trees from Gene Trees in a Radiation of California Trapdoor Spiders (Araneae, Antrodiaetidae, Aliatypus)

    PubMed Central

    Satler, Jordan D.; Starrett, James; Hayashi, Cheryl Y.; Hedin, Marshal

    2011-01-01

    Background The California Floristic Province is a biodiversity hotspot, reflecting a complex geologic history, strong selective gradients, and a heterogeneous landscape. These factors have led to high endemic diversity across many lifeforms within this region, including the richest diversity of mygalomorph spiders (tarantulas, trapdoor spiders, and kin) in North America. The trapdoor spider genus Aliatypus encompasses twelve described species, eleven of which are endemic to California. Several Aliatypus species show disjunct distributional patterns in California (some are found on both sides of the vast Central Valley), and the genus as a whole occupies an impressive variety of habitats. Methodology/Principal Findings We collected specimens from 89 populations representing all described species. DNA sequence data were collected from seven gene regions, including two newly developed for spider systematics. Bayesian inference (in individual gene tree and species tree approaches) recovered a general “3 clade” structure for the genus (A. gulosus, californicus group, erebus group), with three other phylogenetically isolated species differing slightly in position across different phylogenetic analyses. Because of extremely high intraspecific divergences in mitochondrial COI sequences, the relatively slowly evolving 28S rRNA gene was found to be more useful than mitochondrial data for identification of morphologically indistinguishable immatures. For multiple species spanning the Central Valley, explicit hypothesis testing suggests a lack of monophyly for regional populations (e.g., western Coast Range populations). Phylogenetic evidence clearly shows that syntopy is restricted to distant phylogenetic relatives, consistent with ecological niche conservatism. Conclusions/Significance This study provides fundamental insight into a radiation of trapdoor spiders found in the biodiversity hotspot of California. Species relationships are clarified and undescribed lineages

  19. Relating tree growth to rainfall in Bolivian rain forests: a test for six species using tree ring analysis.

    PubMed

    Brienen, Roel J W; Zuidema, Pieter A

    2005-11-01

    Many tropical regions show one distinct dry season. Often, this seasonality induces cambial dormancy of trees, particularly if these belong to deciduous species. This will often lead to the formation of annual rings. The aim of this study was to determine whether tree species in the Bolivian Amazon region form annual rings and to study the influence of the total amount and seasonal distribution of rainfall on diameter growth. Ring widths were measured on stem discs of a total of 154 trees belonging to six rain forest species. By correlating ring width and monthly rainfall data we proved the annual character of the tree rings for four of our study species. For two other species the annual character was proved by counting rings on trees of known age and by radiocarbon dating. The results of the climate-growth analysis show a positive relationship between tree growth and rainfall in certain periods of the year, indicating that rainfall plays a major role in tree growth. Three species showed a strong relationship with rainfall at the beginning of the rainy season, while one species is most sensitive to the rainfall at the end of the previous growing season. These results clearly demonstrate that tree ring analysis can be successfully applied in the tropics and that it is a promising method for various research disciplines. PMID:16012820

  20. Urban Tree Species Show the Same Hydraulic Response to Vapor Pressure Deficit across Varying Tree Size and Environmental Conditions

    PubMed Central

    Chen, Lixin; Zhang, Zhiqiang; Ewers, Brent E.

    2012-01-01

    Background The functional convergence of tree transpiration has rarely been tested for tree species growing under urban conditions even though it is of significance to elucidate the relationship between functional convergence and species differences of urban trees for establishing sustainable urban forests in the context of forest water relations. Methodology/Principal Findings We measured sap flux of four urban tree species including Cedrus deodara, Zelkova schneideriana, Euonymus bungeanus and Metasequoia glyptostroboides in an urban park by using thermal dissipation probes (TDP). The concurrent microclimate conditions and soil moisture content were also measured. Our objectives were to examine 1) the influence of tree species and size on transpiration, and 2) the hydraulic control of urban trees under different environmental conditions over the transpiration in response to VPD as represented by canopy conductance. The results showed that the functional convergence between tree diameter at breast height (DBH) and tree canopy transpiration amount (Ec) was not reliable to predict stand transpiration and there were species differences within same DBH class. Species differed in transpiration patterns to seasonal weather progression and soil water stress as a result of varied sensitivity to water availability. Species differences were also found in their potential maximum transpiration rate and reaction to light. However, a same theoretical hydraulic relationship between Gc at VPD = 1 kPa (Gcref) and the Gc sensitivity to VPD (−dGc/dlnVPD) across studied species as well as under contrasting soil water and Rs conditions in the urban area. Conclusions/Significance We concluded that urban trees show the same hydraulic regulation over response to VPD across varying tree size and environmental conditions and thus tree transpiration could be predicted with appropriate assessment of Gcref. PMID:23118904

  1. Does Mutualism Drive the Invasion of Two Alien Species? The Case of Solenopsis invicta and Phenacoccus solenopsis

    PubMed Central

    Zhou, Aiming; Lu, Yongyue; Zeng, Ling; Xu, Yijuan; Liang, Guangwen

    2012-01-01

    Although mutualism between ants and honeydew-producing hemipterans has been extensively recognized in ecosystem biology, however few attempts to test the hypothesis that mutualism between two alien species leads to the facilitation of the invasion process. To address this problem, we focus on the conditional mutualism between S. invicta and P. solenopsis by field investigations and indoor experiments. In the laboratory, ant colony growth increased significantly when ants had access to P. solenopsis and animal-based food. Honeydew produced by P. solenopsis also improved the survival of ant workers. In the field, colony density of P. solenopsis was significantly greater on plots with ants than on plots without ants. The number of mealybug mummies on plants without fire ants was almost three times that of plants with fire ants, indicating a strong effect of fire ants on mealybug survival. In addition, the presence of S. invicta successfully contributed to the spread of P. solenopsis. The quantity of honeydew consumption by S. invicta was significantly greater than that of a presumptive native ant, Tapinoma melanocephalum. When compared with the case without ant tending, mealybugs tended by ants matured earlier and their lifespan and reproduction increased. T. melanocephalum workers arrived at honeydew more quickly than S. invicta workers, while the number of foraging S. invicta workers on plants steadily increased, eventually exceeding that number of T. melanocephalum foragers. Overall, these results suggest that the conditional mutualism between S. invicta and P. solenopsis facilitates population growth and fitness of both species. S. invicta tends to acquire much more honeydew and drive away native ants, promoting their predominance. These results suggest that the higher foraging tempo of S. invicta may provide more effective protection of P. solenopsis than native ants. Thus mutualism between these two alien species may facilitate the invasion success of both

  2. Lianas suppress seedling growth and survival of 14 tree species in a Panamanian tropical forest.

    PubMed

    Martínez-Izquierdo, Laura; García, María M; Powers, Jennifer S; Schnitzer, Stefan A

    2016-01-01

    Lianas are a common plant growth form in tropical forests, where they compete intensely with trees, decreasing tree recruitment, growth, and survival. If the detrimental effects of lianas vary significantly with tree species identity, as is often assumed, then lianas may influence tree species diversity and community composition. Furthermore, recent studies have shown that liana abundance and biomass are increasing relative to trees in neotropical forests, which will likely magnify the detrimental effects of lianas and may ultimately alter tree species diversity, relative abundances, and community composition. Few studies, however, have tested the responses of multiple tree species to the presence of lianas in robust, well-replicated experiments. We tested the hypotheses that lianas reduce tree seedling growth and survival, and that the effect of lianas varies with tree species identity. We used a large-scale liana removal experiment in Central Panama in which we planted 14 replicate seedlings of 14 different tree species that varied in shade tolerance in each of 16 80 x 80 m plots (eight liana-removal and eight unmanipulated controls; 3136 total seedlings). Over a nearly two-yr period, we found that tree seedlings survived 75% more, grew 300% taller, and had twice the aboveground biomass in liana-removal plots than seedlings in control plots, consistent with strong competition between lianas and tree seedlings. There were no significant differences in the response of tree species to liana competition (i.e., there was no species by treatment interaction), indicating that lianas had a similar negative effect on all 14 tree species. Furthermore, the effect of lianas did not vary with tree species shade tolerance classification, suggesting that the liana effect was not solely based on light. Based on these findings, recently observed increases in liana abundance in neotropical forests will substantially reduce tree regeneration, but will not significantly alter

  3. Tree diversity and the role of non-host neighbour tree species in reducing fungal pathogen infestation

    PubMed Central

    Hantsch, Lydia; Bien, Steffen; Radatz, Stine; Braun, Uwe; Auge, Harald; Bruelheide, Helge

    2014-01-01

    The degree to which plant pathogen infestation occurs in a host plant is expected to be strongly influenced by the level of species diversity among neighbouring host and non-host plant species. Since pathogen infestation can negatively affect host plant performance, it can mediate the effects of local biodiversity on ecosystem functioning. We tested the effects of tree diversity and the proportion of neighbouring host and non-host species with respect to the foliar fungal pathogens of Tilia cordata and Quercus petraea in the Kreinitz tree diversity experiment in Germany. We hypothesized that fungal pathogen richness increases while infestation decreases with increasing local tree diversity. In addition, we tested whether fungal pathogen richness and infestation are dependent on the proportion of host plant species present or on the proportion of particular non-host neighbouring tree species. Leaves of the two target species were sampled across three consecutive years with visible foliar fungal pathogens on the leaf surface being identified macro- and microscopically. Effects of diversity among neighbouring trees were analysed: (i) for total fungal species richness and fungal infestation on host trees and (ii) for infestation by individual fungal species. We detected four and five fungal species on T. cordata and Q. petraea, respectively. High local tree diversity reduced (i) total fungal species richness and infestation of T. cordata and fungal infestation of Q. petraea and (ii) infestation by three host-specialized fungal pathogen species. These effects were brought about by local tree diversity and were independent of host species proportion. In general, host species proportion had almost no effect on fungal species richness and infestation. Strong effects associated with the proportion of particular non-host neighbouring tree species on fungal species richness and infestation were, however, recorded. Synthesis. For the first time, we experimentally

  4. The Impact of Missing Data on Species Tree Estimation.

    PubMed

    Xi, Zhenxiang; Liu, Liang; Davis, Charles C

    2016-03-01

    Phylogeneticists are increasingly assembling genome-scale data sets that include hundreds of genes to resolve their focal clades. Although these data sets commonly include a moderate to high amount of missing data, there remains no consensus on their impact to species tree estimation. Here, using several simulated and empirical data sets, we assess the effects of missing data on species tree estimation under varying degrees of incomplete lineage sorting (ILS) and gene rate heterogeneity. We demonstrate that concatenation (RAxML), gene-tree-based coalescent (ASTRAL, MP-EST, and STAR), and supertree (matrix representation with parsimony [MRP]) methods perform reliably, so long as missing data are randomly distributed (by gene and/or by species) and that a sufficiently large number of genes are sampled. When data sets are indecisive sensu Sanderson et al. (2010. Phylogenomics with incomplete taxon coverage: the limits to inference. BMC Evol Biol. 10:155) and/or ILS is high, however, high amounts of missing data that are randomly distributed require exhaustive levels of gene sampling, likely exceeding most empirical studies to date. Moreover, missing data become especially problematic when they are nonrandomly distributed. We demonstrate that STAR produces inconsistent results when the amount of nonrandom missing data is high, regardless of the degree of ILS and gene rate heterogeneity. Similarly, concatenation methods using maximum likelihood can be misled by nonrandom missing data in the presence of gene rate heterogeneity, which becomes further exacerbated when combined with high ILS. In contrast, ASTRAL, MP-EST, and MRP are more robust under all of these scenarios. These results underscore the importance of understanding the influence of missing data in the phylogenomics era. PMID:26589995

  5. Interannual Variation in Stand Transpiration is Dependent Upon Tree Species

    NASA Astrophysics Data System (ADS)

    Ewers, B. E.; Mackay, D. S.; Burrows, S. N.; Ahl, D. E.; Samanta, S.

    2003-12-01

    In order to successfully predict transpirational water fluxes from forested watersheds, interannual variability in transpiration must be quantified and understood. In a heterogeneous forested landscape in northern Wisconsin, we quantified stand transpiration across four forest cover types representing more than 80 percent of the land area in order to 1) quantify differences in stand transpiration and leaf area over two years and 2) determine the mechanisms governing the changes in transpiration over two years. We measured sap flux in eight trees of each tree species in the four cover types. We found that in northern hardwoods, the leaf area of sugar maple increased between the two measurement years with transpiration per unit ground area increasing even more than could be explained by leaf area. In an aspen stand, tent caterpillars completely defoliated the stand for approximately a month until a new set of leaves flushed out. The new set of leaves resulted in a lower leaf area but the same transpiration per unit leaf area indicating there was no physiological compensation for the lower leaf area. At the same time, balsam fir growing underneath the aspen increased their transpiration rate in response to greater light penetration through the dominant aspen canopy Red pine had a thirty percent change in leaf area within a growing season due to multiple cohorts of leaves and transpiration followed this leaf area dynamic. In a forested wetland, white cedar transpiration was proportional to surface water depth between the two years. Despite the specific tree species' effects on stand transpiration, all species displayed a minimum water potential regulation resulting in a saturating response of transpiration to vapor pressure deficit that did not vary across the two years. This physiological set point will allow future water flux models to explain mechanistically interannual variability in transpiration of this and similar forests.

  6. The invasion of five alien species in the Delta do Parnaíba Environmental Protection Area, Northeastern Brazil.

    PubMed

    Loebmann, Daniel; Mai, Ana Cecília G; Lee, James T

    2010-09-01

    Marine biological invasions have been regarded as one of the major causes of native biodiversity loss, with shipping and aquaculture being the leading contributors for the introductions of alien species in aquatic ecosystems. In the present study, five aquatic alien species (one mollusk, three crustaceans and one fish species) were detected during dives, shore searches and from the fisheries on the coast of the Delta do Parnaíba Environmental Protection Area, in the States of Piauí and Maranhão, Northeastern Brazil. The species were the bicolor purse-oyster Isognomon bicolor, the whiteleg shrimp Litopenaeus vannamei, the giant river prawn Macrobrachium rosenbergii, the Indo-Pacific swimming crab Charybdis hellerii and, the muzzled blenny Omobranchus punctatus. Ballast water (I. bicolor, C. hellerii, and O. punctatus) and aquaculture activities (L. vannamei and M. rosenbergii) in adjacent areas are the most likely vectors of introduction. All exotic species found have potential impact risks to the environment because they are able to compete against native species for resources (food and habitat). Isognomon bicolor share the same habitat and food items with the native bivalve species of mussels and barnacles. Litopenaeus vannamei share the same habitat and food items with the native penaeids such as the pinkspot shrimp Farfantepenaeus brasiliensis, the Southern brown shrimp Farfantepenaeus subtilis, and the Southern white shrimp Litopenaeus schmitti, and in the past few years L. vannamei was responsible for a viral epidemics in the cultivation tanks that could be transmitted to native penaeid shrimps. Charybdis hellerii is also able to cause impacts on the local fisheries as the species can decrease the populations of native portunid crabs which are commercialized in the studied region. Macrobrachium rosenbergii may be sharing natural resources with the Amazon River prawn Macrobrachium amazonicum. Omobranchus punctatus shares habit with the native redlip blenny

  7. Nitrogen and phosphorus additions negatively affect tree species diversity in tropical forest regrowth trajectories.

    PubMed

    Siddique, Ilyas; Vieira, Ima Célia Guimarães; Schmidt, Susanne; Lamb, David; Carvalho, Cláudio José Reis; Figueiredo, Ricardo de Oliveira; Blomberg, Simon; Davidson, Eric A

    2010-07-01

    Nutrient enrichment is increasingly affecting many tropical ecosystems, but there is no information on how this affects tree biodiversity. To examine dynamics in vegetation structure and tree species biomass and diversity, we annually remeasured tree species before and for six years after repeated additions of nitrogen (N) and phosphorus (P) in permanent plots of abandoned pasture in Amazonia. Nitrogen and, to a lesser extent, phosphorus addition shifted growth among woody species. Nitrogen stimulated growth of two common pioneer tree species and one common tree species adaptable to both high- and low-light environments, while P stimulated growth only of the dominant pioneer tree Rollinia exsucca (Annonaceae). Overall, N or P addition reduced tree assemblage evenness and delayed tree species accrual over time, likely due to competitive monopolization of other resources by the few tree species responding to nutrient enrichment with enhanced establishment and/or growth rates. Absolute tree growth rates were elevated for two years after nutrient addition. However, nutrient-induced shifts in relative tree species growth and reduced assemblage evenness persisted for more than three years after nutrient addition, favoring two nutrient-responsive pioneers and one early-secondary tree species. Surprisingly, N + P effects on tree biomass and species diversity were consistently weaker than N-only and P-only effects, because grass biomass increased dramatically in response to N + P addition. The resulting intensified competition probably prevented an expected positive N + P synergy in the tree assemblage. Thus, N or P enrichment may favor unknown tree functional response types, reduce the diversity of coexisting species, and delay species accrual during structurally and functionally complex tropical rainforest secondary succession. PMID:20715634

  8. Tree Species Specific Soil Moisture Patterns and Dynamics

    NASA Astrophysics Data System (ADS)

    Heidbuechel, I.; Dreibrodt, J.; Guntner, A.; Blume, T.

    2014-12-01

    Land use has a major influence on the hydrologic processes that take place in soils. Soil compaction on pastures for example leads to infiltration patterns that differ considerably from the ones observable in forests. It is not clear, however, how different forest stands influence soil infiltration and soil moisture distributions. Factors that that vary amongst different stands and potentially affect soil moisture processes in forests are, amongst others, canopy density, throughfall patterns, the intensity and frequency of stem flow, litter type, root distributions and rooting depth. To investigate how different tree species influence the way soils partition, store and conduct incoming precipitation we selected 15 locations under different tree stands within the TERENO observatory in north-east Germany. The forest stands under investigation were mature oak, young pine, mature pine, young beech and mature beech. At each location we installed 30 FDR soil moisture sensors grouped into five depth profiles (monitoring soil moisture from 10 cm to 200 cm) and 5 additional near surface sensors. The profile locations within each forest stand covered most of the anticipated variability by ranging from minimum to maximum distance to the trees including locations under more and less dense canopy. Supplementary to the FDR sensors, throughfall measurements, tensiometers and groundwater data were available to observe dynamics of tree water availability, water fluxes within the soils and percolation towards the groundwater. To identify patterns in space and time we referred to the statistical methods of wavelet analysis and temporal stability analysis. Finally, we tried to link the results from these analyses to specific hydrologic processes at the different locations.

  9. Consistency and inconsistency of consensus methods for inferring species trees from gene trees in the presence of ancestral population structure.

    PubMed

    DeGiorgio, Michael; Rosenberg, Noah A

    2016-08-01

    In the last few years, several statistically consistent consensus methods for species tree inference have been devised that are robust to the gene tree discordance caused by incomplete lineage sorting in unstructured ancestral populations. One source of gene tree discordance that has only recently been identified as a potential obstacle for phylogenetic inference is ancestral population structure. In this article, we describe a general model of ancestral population structure, and by relying on a single carefully constructed example scenario, we show that the consensus methods Democratic Vote, STEAC, STAR, R(∗) Consensus, Rooted Triple Consensus, Minimize Deep Coalescences, and Majority-Rule Consensus are statistically inconsistent under the model. We find that among the consensus methods evaluated, the only method that is statistically consistent in the presence of ancestral population structure is GLASS/Maximum Tree. We use simulations to evaluate the behavior of the various consensus methods in a model with ancestral population structure, showing that as the number of gene trees increases, estimates on the basis of GLASS/Maximum Tree approach the true species tree topology irrespective of the level of population structure, whereas estimates based on the remaining methods only approach the true species tree topology if the level of structure is low. However, through simulations using species trees both with and without ancestral population structure, we show that GLASS/Maximum Tree performs unusually poorly on gene trees inferred from alignments with little information. This practical limitation of GLASS/Maximum Tree together with the inconsistency of other methods prompts the need for both further testing of additional existing methods and development of novel methods under conditions that incorporate ancestral population structure. PMID:27086043

  10. Does Hawaiian native forest conserve water? Lower uptake rates at tree and stand scale by Metrosideros polymorpha relative to plantation species

    NASA Astrophysics Data System (ADS)

    Kagawa, A. K.; Sack, L.; Duarte, T. K.; James, S. A.

    2007-12-01

    Native plants are often claimed to be conservative water users that enhance groundwater recharge compared to faster-growing non-native species that tend to dominate watersheds. This argument would have implications for motivating conservation and restoration of native forest in Hawai'i. However, few studies have examined differences in native and non-native plant transpiration (water use) at species or at stand level. Our aim was determine whether species matter to stand-level water use. We measured plant transpiration in a continuous mosaic of native forest and non-native tree plantation in Honaunau, Hawaii, focusing on endemic dominant tree Metrosideros polymorpha, alien timber trees Eucalyptus saligna and Fraxinus uhdei, and dominant understory Cibotium tree ferns. We measured xylem sap flow for six individuals of each species continuously for over eight weeks, and we estimated stand water use by scaling up these measurements using stand sapwood area and tree fern leaf area values obtained through vegetation surveys. Native forest dominant Metrosideros had the lowest rates of whole-tree daily water use at 8 kg day-1 (200kg m-2sapwood day-1), less than half the daily rates for Eucalyptus or Fraxinus; Metrosideros also had the lowest maximum transpiration rates of the three tree species. At the stand level, Fraxinus-dominated stands had higher water use than Eucalyptus- and Metrosideros- dominated stands due to the species' high sap flow rates, five-fold greater sapwood allocation, and the stands' two-fold greater dominant tree density. In Metrosideros-dominated stands, high Cibotium tree fern leaf area contributed to nearly 60% of water use, indicating the fern's critical role in forest water balance. Stand water use was influenced by factors at various scales, including species composition, stem density, tree sizes, and tree species' sapwood allocation, and was affected significantly by understory contributions. These findings highlight the importance of

  11. Neogene origins and implied warmth tolerance of Amazon tree species

    PubMed Central

    Dick, Christopher W; Lewis, Simon L; Maslin, Mark; Bermingham, Eldredge

    2013-01-01

    Tropical rain forest has been a persistent feature in South America for at least 55 million years. The future of the contemporary Amazon forest is uncertain, however, as the region is entering conditions with no past analogue, combining rapidly increasing air temperatures, high atmospheric carbon dioxide concentrations, possible extreme droughts, and extensive removal and modification by humans. Given the long-term Cenozoic cooling trend, it is unknown whether Amazon forests can tolerate air temperature increases, with suggestions that lowland forests lack warm-adapted taxa, leading to inevitable species losses. In response to this uncertainty, we posit a simple hypothesis: the older the age of a species prior to the Pleistocene, the warmer the climate it has previously survived, with Pliocene (2.6–5 Ma) and late-Miocene (8–10 Ma) air temperature across Amazonia being similar to 2100 temperature projections under low and high carbon emission scenarios, respectively. Using comparative phylogeographic analyses, we show that 9 of 12 widespread Amazon tree species have Pliocene or earlier lineages (>2.6 Ma), with seven dating from the Miocene (>5.6 Ma) and three >8 Ma. The remarkably old age of these species suggest that Amazon forests passed through warmth similar to 2100 levels and that, in the absence of other major environmental changes, near-term high temperature-induced mass species extinction is unlikely. PMID:23404439

  12. Evaluating Summary Methods for Multilocus Species Tree Estimation in the Presence of Incomplete Lineage Sorting.

    PubMed

    Mirarab, Siavash; Bayzid, Md Shamsuzzoha; Warnow, Tandy

    2016-05-01

    Species tree estimation is complicated by processes, such as gene duplication and loss and incomplete lineage sorting (ILS), that cause discordance between gene trees and the species tree. Furthermore, while concatenation, a traditional approach to tree estimation, has excellent performance under many conditions, the expectation is that the best accuracy will be obtained through the use of species tree estimation methods that are specifically designed to address gene tree discordance. In this article, we report on a study to evaluate MP-EST-one of the most popular species tree estimation methods designed to address ILS-as well as concatenation under maximum likelihood, the greedy consensus, and two supertree methods (Matrix Representation with Parsimony and Matrix Representation with Likelihood). Our study shows that several factors impact the absolute and relative accuracy of methods, including the number of gene trees, the accuracy of the estimated gene trees, and the amount of ILS. Concatenation can be more accurate than the best summary methods in some cases (mostly when the gene trees have poor phylogenetic signal or when the level of ILS is low), but summary methods are generally more accurate than concatenation when there are an adequate number of sufficiently accurate gene trees. Our study suggests that coalescent-based species tree methods may be key to estimating highly accurate species trees from multiple loci. PMID:25164915

  13. The complex biogeographic history of a widespread tropical tree species.

    PubMed

    Dick, Christopher W; Heuertz, Myriam

    2008-11-01

    Many tropical forest tree species have broad geographic ranges, and fossil records indicate that population disjunctions in some species were established millions of years ago. Here we relate biogeographic history to patterns of population differentiation, mutational and demographic processes in the widespread rainforest tree Symphonia globulifera using ribosomal (ITS) and chloroplast DNA sequences and nuclear microsatellite (nSSR) loci. Fossil records document sweepstakes dispersal origins of Neotropical S. globulifera populations from Africa during the Miocene. Despite historical long-distance gene flow, nSSR differentiation across 13 populations from Costa Rica, Panama, Ecuador (east and west of Andes) and French Guiana was pronounced (F(ST)= 0.14, R(ST)= 0.39, P < 0.001) and allele-size mutations contributed significantly (R(ST) > F(ST)) to the divergences between cis- and trans-Andean populations. Both DNA sequence and nSSR data reflect contrasting demographic histories in lower Mesoamerica and Amazonia. Amazon populations show weak phylogeographic structure and deviation from drift-mutation equilibrium indicating recent population expansion. In Mesoamerica, genetic drift was strong and contributed to marked differentiation among populations. The genetic structure of S. globulifera contains fingerprints of drift-dispersal processes and phylogeographic footprints of geological uplifts and sweepstakes dispersal. PMID:18764917

  14. Impact of alien pines on local arbuscular mycorrhizal fungal communities-evidence from two continents.

    PubMed

    Gazol, Antonio; Zobel, Martin; Cantero, Juan José; Davison, John; Esler, Karen J; Jairus, Teele; Öpik, Maarja; Vasar, Martti; Moora, Mari

    2016-06-01

    The introduction of alien plants can influence biodiversity and ecosystems. However, its consequences for soil microbial communities remain poorly understood. We addressed the impact of alien ectomycorrhizal (EcM) pines on local arbuscular mycorrhizal (AM) fungal communities in two regions with contrasting biogeographic histories: in South Africa, where no native EcM plant species are present; and in Argentina, where EcM trees occur naturally. The effect of alien pines on AM fungal communities differed between these regions. In South Africa, plantations of alien EcM pines exhibited lower AM fungal richness and significantly altered community composition, compared with native fynbos. In Argentina, the richness and composition of local AM fungal communities were similar in plantations of alien EcM pines and native forest. However, the presence of alien pines resulted in slight changes to the phylogenetic structure of root AM fungal communities in both regions. In pine clearcut areas in South Africa, the richness and composition of AM fungal communities were intermediate between the native fynbos and the alien pine plantation, which is consistent with natural regeneration of former AM fungal communities following pine removal. We conclude that the response of local AM fungal communities to alien EcM pines differs between biogeographic regions with different histories of species coexistence. PMID:27056916

  15. Firewood crops: shrub and tree species for energy production

    SciTech Connect

    Not Available

    1980-01-01

    In the face of global concern over the dwindling supply of fuelwood, the rate of forest decimation to provide basic human necessities in developing countries is alarming. We must look upon woody plants as renewable resources that, if effectively managed, could alleviate the problem not only for the present,but for posterity. This report suggests potential significant fuelwood species for introduction to suitable environments, although it does not suggest a solution for the fuelwood crisis. The emphasis is on species suitable for individual crops, but species suited to plantation cultivation for fueling small industrial factories, electric generators, and crop driers are also considered. Most of the plants are little known in traditional forest production. Some are woody shrubs rather than trees, but all are aggressive and quick growing. They should be introduced with care in areas where the climate and soil conditions are not harsh. The substitution of well-designed stoves, kilns, or boilers could improve fuel efficiency. Each species is illustrated with photographs and diagrams. (Refs. 420).

  16. Regional climate model downscaling may improve the prediction of alien plant species distributions

    NASA Astrophysics Data System (ADS)

    Liu, Shuyan; Liang, Xin-Zhong; Gao, Wei; Stohlgren, Thomas J.

    2014-12-01

    Distributions of invasive species are commonly predicted with species distribution models that build upon the statistical relationships between observed species presence data and climate data. We used field observations, climate station data, and Maximum Entropy species distribution models for 13 invasive plant species in the United States, and then compared the models with inputs from a General Circulation Model (hereafter GCM-based models) and a downscaled Regional Climate Model (hereafter, RCM-based models).We also compared species distributions based on either GCM-based or RCM-based models for the present (1990-1999) to the future (2046-2055). RCM-based species distribution models replicated observed distributions remarkably better than GCM-based models for all invasive species under the current climate. This was shown for the presence locations of the species, and by using four common statistical metrics to compare modeled distributions. For two widespread invasive taxa ( Bromus tectorum or cheatgrass, and Tamarix spp. or tamarisk), GCM-based models failed miserably to reproduce observed species distributions. In contrast, RCM-based species distribution models closely matched observations. Future species distributions may be significantly affected by using GCM-based inputs. Because invasive plants species often show high resilience and low rates of local extinction, RCM-based species distribution models may perform better than GCM-based species distribution models for planning containment programs for invasive species.

  17. Colonization History, Host Distribution, Anthropogenic Influence and Landscape Features Shape Populations of White Pine Blister Rust, an Invasive Alien Tree Pathogen

    PubMed Central

    Brar, Simren; Tsui, Clement K. M.; Dhillon, Braham; Bergeron, Marie-Josée; Joly, David L.; Zambino, P. J.; El-Kassaby, Yousry A.; Hamelin, Richard C.

    2015-01-01

    White pine blister rust is caused by the fungal pathogen Cronartium ribicola J.C. Fisch (Basidiomycota, Pucciniales). This invasive alien pathogen was introduced into North America at the beginning of the 20th century on pine seedlings imported from Europe and has caused serious economic and ecological impacts. In this study, we applied a population and landscape genetics approach to understand the patterns of introduction and colonization as well as population structure and migration of C. ribicola. We characterized 1,292 samples of C. ribicola from 66 geographic locations in North America using single nucleotide polymorphisms (SNPs) and evaluated the effect of landscape features, host distribution, and colonization history on the structure of these pathogen populations. We identified eastern and western genetic populations in North America that are strongly differentiated. Genetic diversity is two to five times higher in eastern populations than in western ones, which can be explained by the repeated accidental introductions of the pathogen into northeastern North America compared with a single documented introduction into western North America. These distinct genetic populations are maintained by a barrier to gene flow that corresponds to a region where host connectivity is interrupted. Furthermore, additional cryptic spatial differentiation was identified in western populations. This differentiation corresponds to landscape features, such as mountain ranges, and also to host connectivity. We also detected genetic differentiation between the pathogen populations in natural stands and plantations, an indication that anthropogenic movement of this pathogen still takes place. These results highlight the importance of monitoring this invasive alien tree pathogen to prevent admixture of eastern and western populations where different pathogen races occur. PMID:26010250

  18. Quantifying the Establishment Likelihood of Invasive Alien Species Introductions Through Ports with Application to Honeybees in Australia.

    PubMed

    Heersink, Daniel K; Caley, Peter; Paini, Dean R; Barry, Simon C

    2016-05-01

    The cost of an uncontrolled incursion of invasive alien species (IAS) arising from undetected entry through ports can be substantial, and knowledge of port-specific risks is needed to help allocate limited surveillance resources. Quantifying the establishment likelihood of such an incursion requires quantifying the ability of a species to enter, establish, and spread. Estimation of the approach rate of IAS into ports provides a measure of likelihood of entry. Data on the approach rate of IAS are typically sparse, and the combinations of risk factors relating to country of origin and port of arrival diverse. This presents challenges to making formal statistical inference on establishment likelihood. Here we demonstrate how these challenges can be overcome with judicious use of mixed-effects models when estimating the incursion likelihood into Australia of the European (Apis mellifera) and Asian (A. cerana) honeybees, along with the invasive parasites of biosecurity concern they host (e.g., Varroa destructor). Our results demonstrate how skewed the establishment likelihood is, with one-tenth of the ports accounting for 80% or more of the likelihood for both species. These results have been utilized by biosecurity agencies in the allocation of resources to the surveillance of maritime ports. PMID:26482012

  19. Biogenic volatile organic compound emissions from nine tree species used in an urban tree-planting program

    NASA Astrophysics Data System (ADS)

    Curtis, A. J.; Helmig, D.; Baroch, C.; Daly, R.; Davis, S.

    2014-10-01

    The biogenic volatile organic compound (BVOC) emissions of nine urban tree species were studied to assess the air quality impacts from planting a large quantity of these trees in the City and County of Denver, Colorado, through the Mile High Million tree-planting initiative. The deciduous tree species studied were Sugar maple, Ohio buckeye, northern hackberry, Turkish hazelnut, London planetree, American basswood, Littleleaf linden, Valley Forge elm, and Japanese zelkova. These tree species were selected using the i-Tree Species Selector (itreetools.org). BVOC emissions from the selected tree species were investigated to evaluate the Species Selector data under the Colorado climate and environmental growing conditions. Individual tree species were subjected to branch enclosure experiments in which foliar emissions of BVOC were collected onto solid adsorbent cartridges. The cartridge samples were analyzed for monoterpenes (MT), sesquiterpenes (SQT), and other C10-C15 BVOC using thermal desorption-gas chromatography-flame ionization detection/mass spectroscopy (GC-FID/MS). Individual compounds and their emission rates (ER) were identified. MT were observed in all tree species, exhibiting the following total MT basal emission rates (BER; with a 1-σ lower bound, upper bound uncertainty window): Sugar maple, 0.07 (0.02, 0.11) μg g-1 h-1; London planetree, 0.15 (0.02, 0.27) μg g-1 h-1; northern hackberry, 0.33 (0.09, 0.57) μg g-1 h-1; Japanese zelkova, 0.42 (0.26, 0.58) μg g-1 h-1; Littleleaf linden, 0.71 (0.33, 1.09) μg g-1 h-1; Valley Forge elm, 0.96 (0.01, 1.92) μg g-1 h-1; Turkish hazelnut, 1.30 (0.32, 2.23) μg g-1 h-1; American basswood, 1.50 (0.40, 2.70) μg g-1 h-1; and Ohio buckeye, 6.61 (1.76, 11.47) μg g-1 h-1. SQT emissions were seen in five tree species with total SQT BER of: London planetree, 0.11 (0.01, 0.20) μg g-1 h-1; Japanese zelkova, 0.11 (0.05, 0.16) μg g-1 h-1; Littleleaf linden, 0.13 (0.06, 0.21) μg g-1 h-1; northern hackberry, 0.20 (0

  20. Classification of savanna tree species, in the Greater Kruger National Park region, by integrating hyperspectral and LiDAR data in a Random Forest data mining environment

    NASA Astrophysics Data System (ADS)

    Naidoo, L.; Cho, M. A.; Mathieu, R.; Asner, G.

    2012-04-01

    The accurate classification and mapping of individual trees at species level in the savanna ecosystem can provide numerous benefits for the managerial authorities. Such benefits include the mapping of economically useful tree species, which are a key source of food production and fuel wood for the local communities, and of problematic alien invasive and bush encroaching species, which can threaten the integrity of the environment and livelihoods of the local communities. Species level mapping is particularly challenging in African savannas which are complex, heterogeneous, and open environments with high intra-species spectral variability due to differences in geology, topography, rainfall, herbivory and human impacts within relatively short distances. Savanna vegetation are also highly irregular in canopy and crown shape, height and other structural dimensions with a combination of open grassland patches and dense woody thicket - a stark contrast to the more homogeneous forest vegetation. This study classified eight common savanna tree species in the Greater Kruger National Park region, South Africa, using a combination of hyperspectral and Light Detection and Ranging (LiDAR)-derived structural parameters, in the form of seven predictor datasets, in an automated Random Forest modelling approach. The most important predictors, which were found to play an important role in the different classification models and contributed to the success of the hybrid dataset model when combined, were species tree height; NDVI; the chlorophyll b wavelength (466 nm) and a selection of raw, continuum removed and Spectral Angle Mapper (SAM) bands. It was also concluded that the hybrid predictor dataset Random Forest model yielded the highest classification accuracy and prediction success for the eight savanna tree species with an overall classification accuracy of 87.68% and KHAT value of 0.843.

  1. Tree species and functional traits but not species richness affect interrill erosion processes in young subtropical forests

    NASA Astrophysics Data System (ADS)

    Seitz, S.; Goebes, P.; Song, Z.; Bruelheide, H.; Härdtle, W.; Kühn, P.; Li, Y.; Scholten, T.

    2016-01-01

    Soil erosion is seriously threatening ecosystem functioning in many parts of the world. In this context, it is assumed that tree species richness and functional diversity of tree communities can play a critical role in improving ecosystem services such as erosion control. An experiment with 170 micro-scale run-off plots was conducted to investigate the influence of tree species and tree species richness as well as functional traits on interrill erosion in a young forest ecosystem. An interrill erosion rate of 47.5 Mg ha-1 a-1 was calculated. This study provided evidence that different tree species affect interrill erosion differently, while tree species richness did not affect interrill erosion in young forest stands. Thus, different tree morphologies have to be considered, when assessing soil erosion under forest. High crown cover and leaf area index reduced interrill erosion in initial forest ecosystems, whereas rising tree height increased it. Even if a leaf litter cover was not present, the remaining soil surface cover by stones and biological soil crusts was the most important driver for soil erosion control. Furthermore, soil organic matter had a decreasing influence on interrill erosion. Long-term monitoring of soil erosion under closing tree canopies is necessary, and a wide range of functional tree traits should be considered in future research.

  2. Introgression of chromosome segments from multiple alien species in wheat breeding lines with wheat streak mosaic virus resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pyramiding of alien-derived Wheat streak mosaic virus (WSMV) resistance and resistance enhancing genes in wheat is a costeffective and environmentally safe strategy for disease control. PCR-based markers and cytogenetic analysis with genomic in situ hybridisation were applied to identify alien chrom...

  3. Characteristics of successful alien plants.

    PubMed

    van Kleunen, M; Dawson, W; Maurel, N

    2015-05-01

    Herbert Baker arguably initiated the search for species characteristics determining alien plant invasion success, with his formulation of the 'ideal weed'. Today, a profusion of studies has tested a myriad of traits for their importance in explaining success of alien plants, but the multiple, not always appropriate, approaches used have led to some confusion and criticism. We argue that a greater understanding of the characteristics explaining alien plant success requires a refined approach that respects the multistage, multiscale nature of the invasion process. We present a schema of questions we can ask regarding the success of alien species, with the answering of one question in the schema being conditional on the answer of preceding questions (thus acknowledging the nested nature of invasion stages). For each question, we identify traits and attributes of species we believe are likely to be most important in explaining species success, and we make predictions as to how we expect successful aliens to differ from natives and from unsuccessful aliens in their characteristics. We organize the findings of empirical studies according to the questions in our schema that they have addressed, to assess the extent to which they support our predictions. We believe that research on plant traits of alien species has already told us a lot about why some alien species become successful after introduction. However, if we ask the right questions at the appropriate scale and use appropriate comparators, research on traits may tell us whether they are really important or not, and if so under which conditions. PMID:25421056

  4. The environmental consequences of alien species in the Swedish lakes Mälaren, Hjälmaren, Vänern and Vättern.

    PubMed

    Josefsson, M; Andersson, B

    2001-12-01

    Twenty alien species have become established in the lakes Mälaren, Vänern, Vättern and Hjälmaren. Intentional introductions include fish and the signal crayfish from North America, ornamental plants, and the Canada goose. Unintentional introductions include the crayfish plague introduced with infected crayfish, the zebra mussel, and Chinese mitten crab introduced with ballast water. The introduction of pathogens and parasites, in particular the crayfish plague, to the lakes has had the greatest environmental and socioeconomic effects and has contributed to the decimation of the indigenous noble crayfish. The stocking of brown trout and salmon with origins from different biogeographical regions has contributed to the extinction of relict indigenous fish species in L. Vänern. Although major ecosystem damage caused by the introduction of alien species, with the exception of the crayfish plague, has not occurred in the four large Swedish lakes, local problems of considerable dignity occur occasionally. PMID:11878025

  5. Higher levels of multiple ecosystem services are found in forests with more tree species.

    PubMed

    Gamfeldt, Lars; Snäll, Tord; Bagchi, Robert; Jonsson, Micael; Gustafsson, Lena; Kjellander, Petter; Ruiz-Jaen, María C; Fröberg, Mats; Stendahl, Johan; Philipson, Christopher D; Mikusiński, Grzegorz; Andersson, Erik; Westerlund, Bertil; Andrén, Henrik; Moberg, Fredrik; Moen, Jon; Bengtsson, Jan

    2013-01-01

    Forests are of major importance to human society, contributing several crucial ecosystem services. Biodiversity is suggested to positively influence multiple services but evidence from natural systems at scales relevant to management is scarce. Here, across a scale of 400,000 km(2), we report that tree species richness in production forests shows positive to positively hump-shaped relationships with multiple ecosystem services. These include production of tree biomass, soil carbon storage, berry production and game production potential. For example, biomass production was approximately 50% greater with five than with one tree species. In addition, we show positive relationships between tree species richness and proxies for other biodiversity components. Importantly, no single tree species was able to promote all services, and some services were negatively correlated to each other. Management of production forests will therefore benefit from considering multiple tree species to sustain the full range of benefits that the society obtains from forests. PMID:23299890

  6. Higher levels of multiple ecosystem services are found in forests with more tree species

    PubMed Central

    Gamfeldt, Lars; Snäll, Tord; Bagchi, Robert; Jonsson, Micael; Gustafsson, Lena; Kjellander, Petter; Ruiz-Jaen, María C.; Fröberg, Mats; Stendahl, Johan; Philipson, Christopher D.; Mikusiński, Grzegorz; Andersson, Erik; Westerlund, Bertil; Andrén, Henrik; Moberg, Fredrik; Moen, Jon; Bengtsson, Jan

    2013-01-01

    Forests are of major importance to human society, contributing several crucial ecosystem services. Biodiversity is suggested to positively influence multiple services but evidence from natural systems at scales relevant to management is scarce. Here, across a scale of 400,000 km2, we report that tree species richness in production forests shows positive to positively hump-shaped relationships with multiple ecosystem services. These include production of tree biomass, soil carbon storage, berry production and game production potential. For example, biomass production was approximately 50% greater with five than with one tree species. In addition, we show positive relationships between tree species richness and proxies for other biodiversity components. Importantly, no single tree species was able to promote all services, and some services were negatively correlated to each other. Management of production forests will therefore benefit from considering multiple tree species to sustain the full range of benefits that the society obtains from forests. PMID:23299890

  7. Temporal changes of soil respiration under different tree species.

    PubMed

    Akburak, Serdar; Makineci, Ender

    2013-04-01

    Soil respiration rates were measured monthly (from April 2007 to March 2008) under four adjacent coniferous plantation sites [Oriental spruce (Picea orientalis L.), Austrian pine (Pinus nigra Arnold), Turkish fir (Abies bornmulleriana L.), and Scots pine (Pinus sylvestris L.)] and adjacent natural Sessile oak forest (Quercus petraea L.) in Belgrad Forest-Istanbul/Turkey. Also, soil moisture, soil temperature, and fine root biomass were determined to identify the underlying environmental variables among sites which are most likely causing differences in soil respiration. Mean annual soil moisture was determined to be between 6.3 % and 8.1 %, and mean annual temperature ranged from 13.0°C to 14.2°C under all species. Mean annual fine root biomass changed between 368.09 g/m(2) and 883.71 g/m(2) indicating significant differences among species. Except May 2007, monthly soil respiration rates show significantly difference among species. However, focusing on tree species, differences of mean annual respiration rates did not differ significantly. Mean annual soil respiration ranged from 0.56 to 1.09 g C/m(2)/day. The highest rates of soil respiration reached on autumn months and the lowest rates were determined on summer season. Soil temperature, soil moisture, and fine root biomass explain mean annual soil respiration rates at the highest under Austrian pine (R (2) = 0.562) and the lowest (R (2) = 0.223) under Turkish fir. PMID:22828980

  8. Differential parasitism of seed-feeding Cydia (Lepidoptera: Tortricidae) by native and alien wasp species relative to elevation in subalpine Sophora (Fabaceae) forests on Mauna Kea, Hawaii

    USGS Publications Warehouse

    Oboyski, P.T.; Slotterback, J.W.; Banko, P.C.

    2004-01-01

    Alien parasitic wasps, including accidental introductions and purposefully released biological control agents, have been implicated in the decline of native Hawaiian Lepidoptera. Understanding the potential impacts of alien wasps requires knowledge of ecological parameters that influence parasitism rates for species in their new environment. Sophora seed-feeding Cydia spp. (Lepidoptera: Tortricidae) were surveyed for larval parasitoids to determine how native and alien wasps are partitioned over an elevation gradient (2200-2800 m) on Hawaii Island, Hawaii. Parasitism rate of native Euderus metallicus (Eulophidae) increased with increased elevation, while parasitism rate by immigrant Calliephialtes grapholithae (Ichneumonidae) decreased. Parasitism by Pristomerus hawaiiensis (Ichneumonidae), origins uncertain, also decreased with increased elevation. Two other species, Diadegma blackburni (Ichneumonidae), origins uncertain, and Brasema cushmani (Eupelmidae), a purposefully introduced biological control agent for pepper weevil, did not vary significantly with elevation. Results are contrasted with a previous study of this system with implications for the conservation of an endangered bird species that feed on Cydia larvae. Interpretation of results is hindered by lack of knowledge of autecology of moths and wasps, origins, phylogeny, systematics, competitive ability, and physiological limitations of each wasp species. These factors should be incorporated into risk analysis for biological control introductions and invasive species programs. ?? 2004 Kluwer Academic Publishers.

  9. Tree species composition affects the abundance of rowan (Sorbus aucuparia L.) in urban forests in Finland.

    PubMed

    Hamberg, Leena; Lehvävirta, Susanna; Kotze, D Johan; Heikkinen, Juha

    2015-03-15

    Recent studies have shown a considerable increase in the abundance of rowan (Sorbus aucuparia) saplings in urban forests in Finland, yet the reasons for this increase are not well understood. Here we investigated whether canopy cover or tree species composition, i.e., the basal areas of different tree species in Norway spruce dominated urban forests, affects the abundances of rowan seedlings, saplings and trees. Altogether 24 urban forest patches were investigated. We sampled the number of rowan and other saplings, and calculated the basal areas of trees. We showed that rowan abundance was affected by tree species composition. The basal area of rowan trees (≥ 5 cm in diameter at breast height, dbh) decreased with increasing basal area of Norway spruce, while the cover of rowan seedlings increased with an increase in Norway spruce basal area. However, a decrease in the abundance of birch (Betula pendula) and an increase in the broad-leaved tree group (Acer platanoides, Alnus glutinosa, Alnus incana, Amelanchier spicata, Prunus padus, Quercus robur, Rhamnus frangula and Salix caprea) coincided with a decreasing number of rowans. Furthermore, rowan saplings were scarce in the vicinity of mature rowan trees. Although it seems that tree species composition has an effect on rowan, the relationship between rowan saplings and mature trees is complex, and therefore we conclude that regulating tree species composition is not an easy way to keep rowan thickets under control in urban forests in Finland. PMID:25588119

  10. Tree species identity and functional traits but not species richness affect interrill erosion processes in young subtropical forests

    NASA Astrophysics Data System (ADS)

    Seitz, S.; Goebes, P.; Song, Z.; Bruelheide, H.; Härdtle, W.; Kühn, P.; Li, Y.; Scholten, T.

    2015-06-01

    Soil erosion is seriously threatening ecosystem functioning in many parts of the world. In this context, it is assumed that tree species richness and functional diversity of tree communities can play a critical role in improving ecosystem services such as erosion control. An experiment with 170 micro-scale runoff plots was conducted to investigate the influence of tree species richness and identity as well as tree functional traits on interrill erosion in a young forest ecosystem. An interrill erosion rate of 47.5 t ha-1 a-1 was calculated. This study provided evidence that different tree species affect interrill erosion, but higher tree species richness did not mitigate soil losses in young forest stands. Thus, different tree morphologies have to be considered, when assessing erosion under forest. High crown cover and leaf area index reduced soil losses in initial forest ecosystems, whereas rising tree height increased them. Even if a leaf litter cover was not present, remaining soil surface cover by stones and biological soil crusts was the most important driver for soil erosion control. Furthermore, soil organic matter had a decreasing influence on soil loss. Long-term monitoring of soil erosion under closing tree canopies is necessary and a wide range of functional tree traits should be taken into consideration in future research.

  11. Species identity and neighbor size surpass the impact of tree species diversity on productivity in experimental broad-leaved tree sapling assemblages under dry and moist conditions

    PubMed Central

    Lübbe, Torben; Schuldt, Bernhard; Leuschner, Christoph

    2015-01-01

    Species diversity may increase the productivity of tree communities through complementarity (CE) and/or selection effects (SE), but it is not well known how this relationship changes under water limitation. We tested the stress-gradient hypothesis, which predicts that resource use complementarity and facilitation are more important under water-limited conditions. We conducted a growth experiment with saplings of five temperate broad-leaved tree species that were grown in assemblages of variable diversity (1, 3, or 5 species) and species composition under ample and limited water supply to examine effects of species richness and species identity on stand- and tree-level productivity. Special attention was paid to effects of neighbor identity on the growth of target trees in mixture as compared to growth in monoculture. Stand productivity was strongly influenced by species identity while a net biodiversity effect (NE) was significant in the moist treatment (mostly assignable to CE) but of minor importance. The growth performance of some of the species in the mixtures was affected by tree neighborhood characteristics with neighbor size likely being more important than neighbor species identity. Diversity and neighbor identity effects visible in the moist treatment mostly disappeared in the dry treatment, disproving the stress-gradient hypothesis. The mixtures were similarly sensitive to drought-induced growth reduction as the monocultures, which may relate to the decreased CE on growth upon drought in the mixtures. PMID:26579136

  12. Species identity and neighbor size surpass the impact of tree species diversity on productivity in experimental broad-leaved tree sapling assemblages under dry and moist conditions.

    PubMed

    Lübbe, Torben; Schuldt, Bernhard; Leuschner, Christoph

    2015-01-01

    Species diversity may increase the productivity of tree communities through complementarity (CE) and/or selection effects (SE), but it is not well known how this relationship changes under water limitation. We tested the stress-gradient hypothesis, which predicts that resource use complementarity and facilitation are more important under water-limited conditions. We conducted a growth experiment with saplings of five temperate broad-leaved tree species that were grown in assemblages of variable diversity (1, 3, or 5 species) and species composition under ample and limited water supply to examine effects of species richness and species identity on stand- and tree-level productivity. Special attention was paid to effects of neighbor identity on the growth of target trees in mixture as compared to growth in monoculture. Stand productivity was strongly influenced by species identity while a net biodiversity effect (NE) was significant in the moist treatment (mostly assignable to CE) but of minor importance. The growth performance of some of the species in the mixtures was affected by tree neighborhood characteristics with neighbor size likely being more important than neighbor species identity. Diversity and neighbor identity effects visible in the moist treatment mostly disappeared in the dry treatment, disproving the stress-gradient hypothesis. The mixtures were similarly sensitive to drought-induced growth reduction as the monocultures, which may relate to the decreased CE on growth upon drought in the mixtures. PMID:26579136

  13. Species Tree Estimation for the Late Blight Pathogen, Phytophthora infestans, and Close Relatives

    PubMed Central

    Blair, Jaime E.; Coffey, Michael D.; Martin, Frank N.

    2012-01-01

    To better understand the evolutionary history of a group of organisms, an accurate estimate of the species phylogeny must be known. Traditionally, gene trees have served as a proxy for the species tree, although it was acknowledged early on that these trees represented different evolutionary processes. Discordances among gene trees and between the gene trees and the species tree are also expected in closely related species that have rapidly diverged, due to processes such as the incomplete sorting of ancestral polymorphisms. Recently, methods have been developed for the explicit estimation of species trees, using information from multilocus gene trees while accommodating heterogeneity among them. Here we have used three distinct approaches to estimate the species tree for five Phytophthora pathogens, including P. infestans, the causal agent of late blight disease in potato and tomato. Our concatenation-based “supergene” approach was unable to resolve relationships even with data from both the nuclear and mitochondrial genomes, and from multiple isolates per species. Our multispecies coalescent approach using both Bayesian and maximum likelihood methods was able to estimate a moderately supported species tree showing a close relationship among P. infestans, P. andina, and P. ipomoeae. The topology of the species tree was also identical to the dominant phylogenetic history estimated in our third approach, Bayesian concordance analysis. Our results support previous suggestions that P. andina is a hybrid species, with P. infestans representing one parental lineage. The other parental lineage is not known, but represents an independent evolutionary lineage more closely related to P. ipomoeae. While all five species likely originated in the New World, further study is needed to determine when and under what conditions this hybridization event may have occurred. PMID:22615869

  14. A Bayesian Supertree Model for Genome-Wide Species Tree Reconstruction

    PubMed Central

    De Oliveira Martins, Leonardo; Mallo, Diego; Posada, David

    2016-01-01

    Current phylogenomic data sets highlight the need for species tree methods able to deal with several sources of gene tree/species tree incongruence. At the same time, we need to make most use of all available data. Most species tree methods deal with single processes of phylogenetic discordance, namely, gene duplication and loss, incomplete lineage sorting (ILS) or horizontal gene transfer. In this manuscript, we address the problem of species tree inference from multilocus, genome-wide data sets regardless of the presence of gene duplication and loss and ILS therefore without the need to identify orthologs or to use a single individual per species. We do this by extending the idea of Maximum Likelihood (ML) supertrees to a hierarchical Bayesian model where several sources of gene tree/species tree disagreement can be accounted for in a modular manner. We implemented this model in a computer program called guenomu whose inputs are posterior distributions of unrooted gene tree topologies for multiple gene families, and whose output is the posterior distribution of rooted species tree topologies. We conducted extensive simulations to evaluate the performance of our approach in comparison with other species tree approaches able to deal with more than one leaf from the same species. Our method ranked best under simulated data sets, in spite of ignoring branch lengths, and performed well on empirical data, as well as being fast enough to analyze relatively large data sets. Our Bayesian supertree method was also very successful in obtaining better estimates of gene trees, by reducing the uncertainty in their distributions. In addition, our results show that under complex simulation scenarios, gene tree parsimony is also a competitive approach once we consider its speed, in contrast to more sophisticated models. PMID:25281847

  15. Remnant Trees Affect Species Composition but Not Structure of Tropical Second-Growth Forest

    PubMed Central

    Sandor, Manette E.; Chazdon, Robin L.

    2014-01-01

    Remnant trees, spared from cutting when tropical forests are cleared for agriculture or grazing, act as nuclei of forest regeneration following field abandonment. Previous studies on remnant trees were primarily conducted in active pasture or old fields abandoned in the previous 2–3 years, and focused on structure and species richness of regenerating forest, but not species composition. Our study is among the first to investigate the effects of remnant trees on neighborhood forest structure, biodiversity, and species composition 20 years post-abandonment. We compared the woody vegetation around individual remnant trees to nearby plots without remnant trees in the same second-growth forests (“control plots”). Forest structure beneath remnant trees did not differ significantly from control plots. Species richness and species diversity were significantly higher around remnant trees. The species composition around remnant trees differed significantly from control plots and more closely resembled the species composition of nearby old-growth forest. The proportion of old-growth specialists and generalists around remnant trees was significantly greater than in control plots. Although previous studies show that remnant trees may initially accelerate secondary forest growth, we found no evidence that they locally affect stem density, basal area, and seedling density at later stages of regrowth. Remnant trees do, however, have a clear effect on the species diversity, composition, and ecological groups of the surrounding woody vegetation, even after 20 years of forest regeneration. To accelerate the return of diversity and old-growth forest species into regrowing forest on abandoned land, landowners should be encouraged to retain remnant trees in agricultural or pastoral fields. PMID:24454700

  16. Evaluating the "recovery level" of endangered species without prior information before alien invasion.

    PubMed

    Watari, Yuya; Nishijima, Shota; Fukasawa, Marina; Yamada, Fumio; Abe, Shintaro; Miyashita, Tadashi

    2013-11-01

    For maintaining social and financial support for eradication programs of invasive species, quantitative assessment of recovery of native species or ecosystems is important because it provides a measurable parameter of success. However, setting a concrete goal for recovery is often difficult owing to lack of information prior to the introduction of invaders. Here, we present a novel approach to evaluate the achievement level of invasive predator management based on the carrying capacity of endangered species estimated using long-term monitoring data. In Amami-Oshima Island, Japan, where the eradication project of introduced small Indian mongoose is ongoing since 2000, we surveyed the population densities of four endangered species threatened by the mongoose (Amami rabbit, the Otton frog, Amami tip-nosed frog, and Amami Ishikawa's frog) at four time points ranging from 2003 to 2011. We estimated the carrying capacities of these species using the logistic growth model combined with the effects of mongoose predation and environmental heterogeneity. All species showed clear tendencies toward increasing their density in line with decreased mongoose density, and they exhibited density-dependent population growth. The estimated carrying capacities of three endangered species had small confidence intervals enough to measure recovery levels by the mongoose management. The population density of each endangered species has recovered to the level of the carrying capacity at about 20-40% of all sites, whereas no individuals were observed at more than 25% of all sites. We propose that the present approach involving appropriate monitoring data of native organism populations will be widely applicable to various eradication projects and provide unambiguous goals for management of invasive species. PMID:24363899

  17. The contribution of seed dispersers to tree species diversity in tropical rainforests.

    PubMed

    Kakishima, Satoshi; Morita, Satoru; Yoshida, Katsuhiko; Ishida, Atsushi; Hayashi, Saki; Asami, Takahiro; Ito, Hiromu; Miller, Donald G; Uehara, Takashi; Mori, Shigeta; Hasegawa, Eisuke; Matsuura, Kenji; Kasuya, Eiiti; Yoshimura, Jin

    2015-10-01

    Tropical rainforests are known for their extreme biodiversity, posing a challenging problem in tropical ecology. Many hypotheses have been proposed to explain the diversity of tree species, yet our understanding of this phenomenon remains incomplete. Here, we consider the contribution of animal seed dispersers to the species diversity of trees. We built a multi-layer lattice model of trees whose animal seed dispersers are allowed to move only in restricted areas to disperse the tree seeds. We incorporated the effects of seed dispersers in the traditional theory of allopatric speciation on a geological time scale. We modified the lattice model to explicitly examine the coexistence of new tree species and the resulting high biodiversity. The results indicate that both the coexistence and diversified evolution of tree species can be explained by the introduction of animal seed dispersers. PMID:26587246

  18. The contribution of seed dispersers to tree species diversity in tropical rainforests

    PubMed Central

    Kakishima, Satoshi; Morita, Satoru; Yoshida, Katsuhiko; Ishida, Atsushi; Hayashi, Saki; Asami, Takahiro; Ito, Hiromu; Miller, Donald G.; Uehara, Takashi; Mori, Shigeta; Hasegawa, Eisuke; Matsuura, Kenji; Kasuya, Eiiti; Yoshimura, Jin

    2015-01-01

    Tropical rainforests are known for their extreme biodiversity, posing a challenging problem in tropical ecology. Many hypotheses have been proposed to explain the diversity of tree species, yet our understanding of this phenomenon remains incomplete. Here, we consider the contribution of animal seed dispersers to the species diversity of trees. We built a multi-layer lattice model of trees whose animal seed dispersers are allowed to move only in restricted areas to disperse the tree seeds. We incorporated the effects of seed dispersers in the traditional theory of allopatric speciation on a geological time scale. We modified the lattice model to explicitly examine the coexistence of new tree species and the resulting high biodiversity. The results indicate that both the coexistence and diversified evolution of tree species can be explained by the introduction of animal seed dispersers. PMID:26587246

  19. Landscape Variation in Tree Species Richness in Northern Iran Forests

    PubMed Central

    Bourque, Charles P.-A.; Bayat, Mahmoud

    2015-01-01

    Mapping landscape variation in tree species richness (SR) is essential to the long term management and conservation of forest ecosystems. The current study examines the prospect of mapping field assessments of SR in a high-elevation, deciduous forest in northern Iran as a function of 16 biophysical variables representative of the area’s unique physiography, including topography and coastal placement, biophysical environment, and forests. Basic to this study is the development of moderate-resolution biophysical surfaces and associated plot-estimates for 202 permanent sampling plots. The biophysical variables include: (i) three topographic variables generated directly from the area’s digital terrain model; (ii) four ecophysiologically-relevant variables derived from process models or from first principles; and (iii) seven variables of Landsat-8-acquired surface reflectance and two, of surface radiance. With symbolic regression, it was shown that only four of the 16 variables were needed to explain 85% of observed plot-level variation in SR (i.e., wind velocity, surface reflectance of blue light, and topographic wetness indices representative of soil water content), yielding mean-absolute and root-mean-squared error of 0.50 and 0.78, respectively. Overall, localised calculations of wind velocity and surface reflectance of blue light explained about 63% of observed variation in SR, with wind velocity accounting for 51% of that variation. The remaining 22% was explained by linear combinations of soil-water-related topographic indices and associated thresholds. In general, SR and diversity tended to be greatest for plots dominated by Carpinus betulus (involving ≥ 33% of all trees in a plot), than by Fagus orientalis (median difference of one species). This study provides a significant step towards describing landscape variation in SR as a function of modelled and satellite-based information and symbolic regression. Methods in this study are sufficiently general to

  20. Landscape variation in tree species richness in northern Iran forests.

    PubMed

    Bourque, Charles P-A; Bayat, Mahmoud

    2015-01-01

    Mapping landscape variation in tree species richness (SR) is essential to the long term management and conservation of forest ecosystems. The current study examines the prospect of mapping field assessments of SR in a high-elevation, deciduous forest in northern Iran as a function of 16 biophysical variables representative of the area's unique physiography, including topography and coastal placement, biophysical environment, and forests. Basic to this study is the development of moderate-resolution biophysical surfaces and associated plot-estimates for 202 permanent sampling plots. The biophysical variables include: (i) three topographic variables generated directly from the area's digital terrain model; (ii) four ecophysiologically-relevant variables derived from process models or from first principles; and (iii) seven variables of Landsat-8-acquired surface reflectance and two, of surface radiance. With symbolic regression, it was shown that only four of the 16 variables were needed to explain 85% of observed plot-level variation in SR (i.e., wind velocity, surface reflectance of blue light, and topographic wetness indices representative of soil water content), yielding mean-absolute and root-mean-squared error of 0.50 and 0.78, respectively. Overall, localised calculations of wind velocity and surface reflectance of blue light explained about 63% of observed variation in SR, with wind velocity accounting for 51% of that variation. The remaining 22% was explained by linear combinations of soil-water-related topographic indices and associated thresholds. In general, SR and diversity tended to be greatest for plots dominated by Carpinus betulus (involving ≥ 33% of all trees in a plot), than by Fagus orientalis (median difference of one species). This study provides a significant step towards describing landscape variation in SR as a function of modelled and satellite-based information and symbolic regression. Methods in this study are sufficiently general to be

  1. Discovery of an alien species of mayfly in South America (Ephemeroptera)

    PubMed Central

    Salles, Frederico F.; Gattolliat, Jean-Luc; Angeli, Kamila B.; De-Souza, Márcia R.; Gonçalves, Inês C.; Nessimian, Jorge L.; Sartori, Michel

    2014-01-01

    Abstract Despite its wide, almost worldwide distribution, the mayfly genus Cloeon Leach, 1815 (Ephemeroptera: Baetidae) is restricted in the Western hemisphere to North America, where a single species is reported. In the Neotropics, except for some species wrongly attributed to the genus in the past, there are no records of Cloeon. Recently, however, specimens of true Cloeon were collected along the coast of Espírito Santo, Southeastern Brazil. In order to verify the hypothesis that this species was recently introduced to Brazil, our aim was to identify the species based on morphological and molecular characters and to confirm the presence of true representatives of the genus in the Neotropics. Our results revealed that the specimens found in Brazil belong to the Afrotropical species C. smaeleni Lestage, 1924. The identity of the species, its distribution, along with its previous absence in regularly sampled sites, is a clear sign that the specimens of C. smaeleni found in Espírito Santo are introduced, well established, and that the colonization took place very recently. PMID:24843249

  2. ECOLOGICAL RESPONSE SURFACES FOR NORTH AMERICAN BOREAL TREE SPECIES AND THEIR USE IN FOREST CLASSIFICATION

    EPA Science Inventory

    Empirical ecological response surfaces were derived for eight dominant tree species in the boreal forest region of Canada. tepwise logistic regression was used to model species dominance as a response to five climatic predictor variables. he predictor variables (annual snowfall, ...

  3. The description of Paramblynotus delaneyi (Hymenoptera: Liopteridae), a new species from Joshua Tree National Park

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A new species, Paramblynotus delaneyi (Hymenoptera: Liopteridae), is described and characters separating it from the Nearctic species P. zonatus Weld and P. virginianus Liu are discussed. A discussion of the insect biodiversity survey at Joshua Tree National Park is provided....

  4. Fire controls population structure in four dominant tree species in a tropical savanna.

    PubMed

    Lehmann, Caroline E R; Prior, Lynda D; Bowman, David M J S

    2009-09-01

    The persistence of mesic savannas has been theorised as being dependent on disturbances that restrict the number of juveniles growing through the sapling size class to become fire-tolerant trees. We analysed the population structures of four dominant tropical savanna tree species from 30 locations in Kakadu National Park (KNP), northern Australia. We found that across KNP as a whole, the population size structures of these species do not exhibit recruitment bottlenecks. However, individual stands had multimodal size-class distributions and mixtures of tree species consistent with episodic and individualistic recruitment of co-occurring tree species. Using information theory and multimodel inference, we examined the relative importance of fire frequency, stand basal area and elevation difference between a site and permanent water in explaining variations in the proportion of sapling to adult stems in four dominant tree species. This showed that the proportion of the tree population made up of saplings was negatively related to both fire frequencies and stand basal area. Overall, fire frequency has density-dependent effects in the regulation of the transition of saplings to trees in this Australian savanna, due to interactions with stem size, regeneration strategies, growth rates and tree-tree competition. Although stable at the regional scale, the spatiotemporal variability of fire can result in structural and floristic diversity of savanna tree populations. PMID:19629532

  5. Indicator species of essential forest tree species in the Burdur district.

    PubMed

    Negiz, Mehmet Güvenç; Eser, Yunus; Kuzugüdenll, Emre; Izkan, Kürşad

    2015-01-01

    The forests of Burdur district for long have been subjected to over grazing and individual selection. As a result of this, majority of the forest areas in the district were degraded. In the district, afforestation efforts included majority of forestry implementations. It is well known that selecting suitable species plays an important role for achieving afforestation efforts. In this context, knowing the indicator species among the target species would be used in afforestation efforts, studies on the interrelationships between environmental factors and target species distribution is vital for selecting suitable species for a given area. In this study, Anatolian Black pine (Pinus nigra), Red pine (Pinus brutia), Crimean juniper (Juniperus excelsa) and Taurus cedar (Cedrus libani), essential tree species, were considered as target species. The data taken from 100 sample plots in Burdur district was used. Interspecific correlation analysis was performed to determine the positive and negative indicator species among each of the target species. As a result of ICA, 2 positive (Berberis crataegina, Juniperus oxycedrus), 2 negative (Phillyrea latifolia, Quercus coccifera) for Crimean Juniper, I positive (Juniperus oxycedrus), 3 negative (Onopordium acanthium, Fraxinus ornus, Phillyrea latifolia) for Anatolian black pine, 3 positive (Paliurus spina-christi, Quercus coccifer, Crataegus orientalis), 2 negative (Berberis crataegina, Astragalus nanus) for Red pine and 3 positive (Berberis crataegina, Rhamnus oleoides, Astragalus prusianus) 2 negative (Paliurus spina-christi, Quercus cerris) for Taurus cedarwere defined as indicator plant species. In this way, practical information was obtained for selecting the most suitable species, among the target species, for afforestation efforts in Burdur district. PMID:26591889

  6. Spatial Distribution Patterns in the Very Rare and Species-Rich Picea chihuahuana Tree Community (Mexico)

    PubMed Central

    Wehenkel, Christian; Brazão-Protázio, João Marcelo; Carrillo-Parra, Artemio; Martínez-Guerrero, José Hugo; Crecente-Campo, Felipe

    2015-01-01

    The very rare Mexican Picea chihuahuana tree community covers an area of no more than 300 ha in the Sierra Madre Occidental. This special tree community has been the subject of several studies aimed at learning more about the genetic structure and ecology of the species and the potential effects of climate change. The spatial distribution of trees is a result of many ecological processes and can affect the degree of competition between neighbouring trees, tree density, variability in size and distribution, regeneration, survival, growth, mortality, crown formation and the biological diversity within forest communities. Numerous scale-dependent measures have been established in order to describe spatial forest structure. The overall aim of most of these studies has been to obtain data to help design preservation and conservation strategies. In this study, we examined the spatial distribution pattern of trees in the P. chihuahuana tree community in 12 localities, in relation to i) tree stand density, ii) diameter distribution (vertical structure), iii) tree species diversity, iv) geographical latitude and v) tree dominance at a fine scale (in 0.25 ha plots), with the aim of obtaining a better understanding of the complex ecosystem processes and biological diversity. Because of the strongly mixed nature of this tree community, which often produces low population densities of each tree species and random tree fall gaps caused by tree death, we expect aggregated patterns in individual Picea chihuahuana trees and in the P. chihuahuana tree community, repulsive Picea patterns to other tree species and repulsive patterns of young to adult trees. Each location was represented by one plot of 50 x 50 m (0.25 ha) established in the centre of the tree community. The findings demonstrate that the hypothesis of aggregated tree pattern is not applicable to the mean pattern measured by Clark-Evans index, Uniform Angle index and Mean Directional index of the uneven-aged P

  7. Spatial Distribution Patterns in the Very Rare and Species-Rich Picea chihuahuana Tree Community (Mexico).

    PubMed

    Wehenkel, Christian; Brazão-Protázio, João Marcelo; Carrillo-Parra, Artemio; Martínez-Guerrero, José Hugo; Crecente-Campo, Felipe

    2015-01-01

    The very rare Mexican Picea chihuahuana tree community covers an area of no more than 300 ha in the Sierra Madre Occidental. This special tree community has been the subject of several studies aimed at learning more about the genetic structure and ecology of the species and the potential effects of climate change. The spatial distribution of trees is a result of many ecological processes and can affect the degree of competition between neighbouring trees, tree density, variability in size and distribution, regeneration, survival, growth, mortality, crown formation and the biological diversity within forest communities. Numerous scale-dependent measures have been established in order to describe spatial forest structure. The overall aim of most of these studies has been to obtain data to help design preservation and conservation strategies. In this study, we examined the spatial distribution pattern of trees in the P. chihuahuana tree community in 12 localities, in relation to i) tree stand density, ii) diameter distribution (vertical structure), iii) tree species diversity, iv) geographical latitude and v) tree dominance at a fine scale (in 0.25 ha plots), with the aim of obtaining a better understanding of the complex ecosystem processes and biological diversity. Because of the strongly mixed nature of this tree community, which often produces low population densities of each tree species and random tree fall gaps caused by tree death, we expect aggregated patterns in individual Picea chihuahuana trees and in the P. chihuahuana tree community, repulsive Picea patterns to other tree species and repulsive patterns of young to adult trees. Each location was represented by one plot of 50 x 50 m (0.25 ha) established in the centre of the tree community. The findings demonstrate that the hypothesis of aggregated tree pattern is not applicable to the mean pattern measured by Clark-Evans index, Uniform Angle index and Mean Directional index of the uneven-aged P

  8. A review of invasive alien species impacts on eucalypt stands and citrus orchards ecosystem services: towards an integrated management approach.

    PubMed

    Branco, Sofia; Videira, Nuno; Branco, Manuela; Paiva, Maria Rosa

    2015-02-01

    Multidisciplinary knowledge on the impact caused by invasive alien species (IAS) on ecosystems is crucial for guiding policy makers in the adoption of sustainable management measures. This research was focused on insect IAS impacts on two managed ecosystems: eucalypt plantations and citrus orchards. It begins with an identification of the wide range of ecosystem services (ES) and disservices provided by each of these managed ecosystems, according to the methodology proposed by the Millennium Ecosystem Assessment. Subsequently, a comprehensive review of studies that promoted the identification and valuation of direct and indirect impacts IAS impacts on these ecosystems was performed. From the synthesis of previous findings, an integrative management framework is advanced. This links the identification of ES, drivers of change and development of IAS management strategies by means of assessment processes that account for multiple dimensions of ES values. The article concludes with a discussion on the challenges underpinning assessment and valuation approaches that inform the design of inclusive strategies and interventions to tackle IAS impacts. PMID:25463567

  9. Characterizing tropical tree species growth strategies: learning from inter-individual variability and scale invariance.

    PubMed

    Le Bec, Jimmy; Courbaud, Benoit; Le Moguédec, Gilles; Pélissier, Raphaël

    2015-01-01

    Understanding how tropical tree species differ in their growth strategies is critical to predict forest dynamics and assess species coexistence. Although tree growth is highly variable in tropical forests, species maximum growth is often considered as a major axis synthesizing species strategies, with fast-growing pioneer and slow-growing shade tolerant species as emblematic representatives. We used a hierarchical linear mixed model and 21-years long tree diameter increment series in a monsoon forest of the Western Ghats, India, to characterize species growth strategies and question whether maximum growth summarizes these strategies. We quantified both species responses to biotic and abiotic factors and individual tree effects unexplained by these factors. Growth responses to competition and tree size appeared highly variable among species which led to reversals in performance ranking along those two gradients. However, species-specific responses largely overlapped due to large unexplained variability resulting mostly from inter-individual growth differences consistent over time. On average one-third of the variability captured by our model was explained by covariates. This emphasizes the high dimensionality of the tree growth process, i.e. the fact that trees differ in many dimensions (genetics, life history) influencing their growth response to environmental gradients, some being unmeasured or unmeasurable. In addition, intraspecific variability increased as a power function of species maximum growth partly as a result of higher absolute responses of fast-growing species to competition and tree size. However, covariates explained on average the same proportion of intraspecific variability for slow- and fast-growing species, which showed the same range of relative responses to competition and tree size. These results reflect a scale invariance of the growth process, underlining that slow- and fast-growing species exhibit the same range of growth strategies. PMID

  10. Characterizing Tropical Tree Species Growth Strategies: Learning from Inter-Individual Variability and Scale Invariance

    PubMed Central

    Le Bec, Jimmy; Courbaud, Benoit; Le Moguédec, Gilles; Pélissier, Raphaël

    2015-01-01

    Understanding how tropical tree species differ in their growth strategies is critical to predict forest dynamics and assess species coexistence. Although tree growth is highly variable in tropical forests, species maximum growth is often considered as a major axis synthesizing species strategies, with fast-growing pioneer and slow-growing shade tolerant species as emblematic representatives. We used a hierarchical linear mixed model and 21-years long tree diameter increment series in a monsoon forest of the Western Ghats, India, to characterize species growth strategies and question whether maximum growth summarizes these strategies. We quantified both species responses to biotic and abiotic factors and individual tree effects unexplained by these factors. Growth responses to competition and tree size appeared highly variable among species which led to reversals in performance ranking along those two gradients. However, species-specific responses largely overlapped due to large unexplained variability resulting mostly from inter-individual growth differences consistent over time. On average one-third of the variability captured by our model was explained by covariates. This emphasizes the high dimensionality of the tree growth process, i.e. the fact that trees differ in many dimensions (genetics, life history) influencing their growth response to environmental gradients, some being unmeasured or unmeasurable. In addition, intraspecific variability increased as a power function of species maximum growth partly as a result of higher absolute responses of fast-growing species to competition and tree size. However, covariates explained on average the same proportion of intraspecific variability for slow- and fast-growing species, which showed the same range of relative responses to competition and tree size. These results reflect a scale invariance of the growth process, underlining that slow- and fast-growing species exhibit the same range of growth strategies. PMID

  11. The relationship between species diversity and genetic structure in the rare Picea chihuahuana tree species community, Mexico.

    PubMed

    Simental-Rodríguez, Sergio Leonel; Quiñones-Pérez, Carmen Zulema; Moya, Daniel; Hernández-Tecles, Enrique; López-Sánchez, Carlos Antonio; Wehenkel, Christian

    2014-01-01

    Species diversity and genetic diversity, the most basic elements of biodiversity, have long been treated as separate topics, although populations evolve within a community context. Recent studies on community genetics and ecology have suggested that genetic diversity is not completely independent of species diversity. The Mexican Picea chihuahuana Martínez is an endemic species listed as "Endangered" on the Red List. Forty populations of Chihuahua spruce have been identified. This species is often associated with tree species of eight genera in gallery forests. This rare Picea chihuahuana tree community covers an area no more than 300 ha and has been subject of several studies involving different topics such as ecology, genetic structure and climate change. The overall aim of these studies was to obtain a dataset for developing management tools to help decision makers implement preservation and conservation strategies. However, this unique forest tree community may also represent an excellent subject for helping us to understand the interplay between ecological and evolutionary processes in determining community structure and dynamics. The AFLP technique and species composition data were used together to test the hypothesis that species diversity is related to the adaptive genetic structure of some dominant tree species (Picea chihuahuana, Pinus strobiformis, Pseudotsuga menziesii and Populus tremuloides) of the Picea chihuahuana tree community at fourteen locations. The Hill numbers were used as a diversity measure. The results revealed a significant correlation between tree species diversity and genetic structure in Populus tremuloides. Because the relationship between the two levels of diversity was found to be positive for the putative adaptive AFLP detected, genetic and species structures of the tree community were possibly simultaneously adapted to a combination of ecological or environmental factors. The present findings indicate that interactions between

  12. The Relationship between Species Diversity and Genetic Structure in the Rare Picea chihuahuana Tree Species Community, Mexico

    PubMed Central

    Simental-Rodríguez, Sergio Leonel; Quiñones-Pérez, Carmen Zulema; Moya, Daniel; Hernández-Tecles, Enrique; López-Sánchez, Carlos Antonio; Wehenkel, Christian

    2014-01-01

    Species diversity and genetic diversity, the most basic elements of biodiversity, have long been treated as separate topics, although populations evolve within a community context. Recent studies on community genetics and ecology have suggested that genetic diversity is not completely independent of species diversity. The Mexican Picea chihuahuana Martínez is an endemic species listed as “Endangered” on the Red List. Forty populations of Chihuahua spruce have been identified. This species is often associated with tree species of eight genera in gallery forests. This rare Picea chihuahuana tree community covers an area no more than 300 ha and has been subject of several studies involving different topics such as ecology, genetic structure and climate change. The overall aim of these studies was to obtain a dataset for developing management tools to help decision makers implement preservation and conservation strategies. However, this unique forest tree community may also represent an excellent subject for helping us to understand the interplay between ecological and evolutionary processes in determining community structure and dynamics. The AFLP technique and species composition data were used together to test the hypothesis that species diversity is related to the adaptive genetic structure of some dominant tree species (Picea chihuahuana, Pinus strobiformis, Pseudotsuga menziesii and Populus tremuloides) of the Picea chihuahuana tree community at fourteen locations. The Hill numbers were used as a diversity measure. The results revealed a significant correlation between tree species diversity and genetic structure in Populus tremuloides. Because the relationship between the two levels of diversity was found to be positive for the putative adaptive AFLP detected, genetic and species structures of the tree community were possibly simultaneously adapted to a combination of ecological or environmental factors. The present findings indicate that interactions

  13. Tree species richness promotes productivity in temperate forests through strong complementarity between species.

    PubMed

    Morin, Xavier; Fahse, Lorenz; Scherer-Lorenzen, Michael; Bugmann, Harald

    2011-12-01

    Understanding the link between biodiversity and ecosystem functioning (BEF) is pivotal in the context of global biodiversity loss. Yet, long-term effects have been explored only weakly, especially for forests, and no clear evidence has been found regarding the underlying mechanisms. We explore the long-term relationship between diversity and productivity using a forest succession model. Extensive simulations show that tree species richness promotes productivity in European temperate forests across a large climatic gradient, mostly through strong complementarity between species. We show that this biodiversity effect emerges because increasing species richness promotes higher diversity in shade tolerance and growth ability, which results in forests responding faster to small-scale mortality events. Our study generalises results from short-term experiments in grasslands to forest ecosystems and demonstrates that competition for light alone induces a positive effect of biodiversity on productivity, thus providing a new angle for explaining BEF relationships. PMID:21955682

  14. Alien invasive birds.

    PubMed

    Brochier, B; Vangeluwe, D; van den Berg, T

    2010-08-01

    A bird species is regarded as alien invasive if it has been introduced, intentionally or accidentally, to a location where it did not previously occur naturally, becomes capable of establishing a breeding population without further intervention by humans, spreads and becomes a pest affecting the environment, the local biodiversity, the economy and/or society, including human health. European Starling (Sturnus vulgaris), Common Myna (Acridotheres tristis) and Red-vented Bulbul (Pycnonotus cafer) have been included on the list of '100 of the World's Worst Invasive Alien Species', a subset of the Global Invasive Species Database. The 'Delivering Alien Invasive Species Inventories for Europe' project has selected Canada Goose (Branta canadensis), Ruddy Duck (Oxyura jamaicensis), Rose-ringed Parakeet (Psittacula krameri) and Sacred Ibis (Threskiornis aethiopicus) as among 100 of the worst invasive species in Europe. For each of these alien bird species, the geographic range (native and introduced range), the introduction pathway, the general impacts and the management methods are presented. PMID:20919578

  15. Mortality rates associated with crown health for eastern forest tree species.

    PubMed

    Morin, Randall S; Randolph, KaDonna C; Steinman, Jim

    2015-03-01

    The condition of tree crowns is an important indicator of tree and forest health. Crown conditions have been evaluated during inventories of the US Forest Service Forest Inventory and Analysis (FIA) program since 1999. In this study, remeasured data from 55,013 trees on 2616 FIA plots in the eastern USA were used to assess the probability of survival among various tree species using the suite of FIA crown condition variables. Logistic regression procedures were employed to develop models for predicting tree survival. Results of the regression analyses indicated that crown dieback was the most important crown condition variable for predicting tree survival for all species combined and for many of the 15 individual species in the study. The logistic models were generally successful in representing recent tree mortality responses to multiyear infestations of beech bark disease and hemlock woolly adelgid. Although our models are only applicable to trees growing in a forest setting, the utility of models that predict impending tree mortality goes beyond forest inventory or traditional forestry growth and yield models and includes any application where managers need to assess tree health or predict tree mortality including urban forest, recreation, wildlife, and pest management. PMID:25655130

  16. Introgression of FHB Resistance from Alien Species-Derived Lines into Spring Wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have produced and collected over 300 wheat lines derived from the crosses of wheat with wild species related to wheat. Evaluation of these lines for reaction to Fusarium head blight (FHB) identified 74 lines with resistance comparable to “Sumai 3” in two greenhouse seasons. Most of the resistan...

  17. Independent domestications of cultivated tree peonies from different wild peony species.

    PubMed

    Yuan, Jun-Hui; Cornille, Amandine; Giraud, Tatiana; Cheng, Fang-Yun; Hu, Yong-Hong

    2014-01-01

    An understanding of plant domestication history provides insights into general mechanisms of plant adaptation and diversification and can guide breeding programmes that aim to improve cultivated species. Cultivated tree peonies (genus Paeonia L.) are among the most popular ornamental plants in the world; yet, the history of their domestication is still unresolved. Here, we explored whether the domestication in China of historically cultivated peonies, that is, the common and flare cultivated tree peonies, was a single event or whether independent domestications occurred. We used 14 nuclear microsatellite markers and a comprehensive set of 553 tree peonies collected across China, including common tree peonies, flare tree peonies and the wild species or subspecies that are potential contributors to the cultivated tree peonies, that is, Paeonia rockii ssp. rockii, P. rockii ssp. atava, P. jishanensis and P. decomposita. Assignment methods, a principal component analysis and approximate Bayesian computations provided clear evidence for independent domestications of these common tree and flare tree peonies from two distinct and allopatric wild species, P. jishanensis and P. rockii ssp. atava, respectively. This study provides the first example of independent domestications of cultivated trees from distinct species and locations. This work also yields crucial insight into the history of domestication of one of the most popular woody ornamental plants. The cultivated peonies represent an interesting case of parallel and convergent evolution. The information obtained in this study will be valuable both for improving current tree peony breeding strategies and for understanding the mechanisms of domestication, diversification and adaptation in plants. PMID:24138195

  18. Species tree discordance traces to phylogeographic clade boundaries in North American fence lizards (Sceloporus).

    PubMed

    Leaché, Adam D

    2009-12-01

    I investigated the impacts of phylogeographic sampling decisions on species tree estimation in the Sceloporus undulatus species group, a recent radiation of small, insectivorous lizards connected by parapatric and peripatric distribution across North America, using a variety of species tree inference methods (Bayesian estimation of species trees, Bayesian untangling of concordance knots, and minimize deep coalescences). Phylogenetic analyses of 16 specimens representing 4 putative species within S. "undulatus" using complete (8 loci, >5.5 kb) and incomplete (29 loci, >23.6 kb) nuclear data sets result in species trees that share features with the mitochondrial DNA (mtDNA) genealogy at the phylogeographic level but provide new insights into the evolutionary history of the species group. The concatenated nuclear data and mtDNA data both recover 4 major clades connecting populations across North America; however, instances of discordance are localized at the contact zones between adjacent phylogeographic groups. A random sub-sampling experiment designed to vary the phylogeographic samples included across hundreds of replicate species tree inferences suggests that inaccurate species assignments can result in inferred phylogenetic relationships that are dependent upon which particular populations are used as exemplars to represent species and can lead to increased estimates of effective population size. For the phylogeographic data presented here, reassigning specimens with introgressed mtDNA genomes to their prospective species, or excluding them from the analysis altogether, produces species tree topologies that are distinctly different from analyses that utilize mtDNA-based species assignments. Evolutionary biologists working at the interface of phylogeography and phylogenetics are likely to encounter multiple processes influencing gene trees congruence, which increases the relevance of estimating species trees with multilocus nuclear data and models that accommodate

  19. Species-specific effects on throughfall kinetic energy below 12 subtropical tree species are related to leaf traits and tree architecture

    NASA Astrophysics Data System (ADS)

    Goebes, Philipp; Seitz, Steffen; Kühn, Peter; Kröber, Wenzel; Bruelheide, Helge; Li, Ying; von Oheimb, Goddert; Scholten, Thomas

    2015-04-01

    Soil erosion impacts environmental systems widely, especially in subtropical China where high erosion rates occur. The comprehension about the mechanisms that induce soil erosion on agricultural land is broad, but erosion processes below forests are only rarely understood. Especially throughfall kinetic energy (TKE) is influenced by forests and their structure as well as their succession in many ways. Today, many forests are monoculture tree stands due to economic reasons by providing timber, fuel and pulp wood. Therefore, this study investigates the role of different monoculture forest stands on TKE that were afforestated in 2008. The main questions are: Is TKE species-specific? What are characteristic leaf traits and tree architectural parameters that induce a species-specific effect on TKE and by what extend do they contribute to a mediation of species-specific effects on TKE? We measured TKE of 12 different species in subtropical China using sand-filled splash cups during five rainfall events in summer 2013. In addition, 14 leaf traits and tree architectural parameters were registered to link species-specific effects on TKE to vegetation parameters. Our results show that TKE is highly species-specific. Highest TKE was found below Choerospondias axillaris and Sapindus mukorossi, while Schima superba showed lowest TKE. The latter species can be regarded as key species for reduced erosion occurrence. This species effect is mediated by leaf habit, leaf area, leaf pinnation, leaf margin, tree ground diameter, crown base height, tree height, number of branches and LAI as biotic factors and rainfall amount as abiotic factor. Moreover, leaf habit, tree height and LA show high effect sizes on TKE and can be considered as major drivers evoking TKE differences below vegetation.

  20. Surface Water Storage Capacity of Twenty Tree Species in Davis, California.

    PubMed

    Xiao, Qingfu; McPherson, E Gregory

    2016-01-01

    Urban forestry is an important green infrastructure strategy because healthy trees can intercept rainfall, reducing stormwater runoff and pollutant loading. Surface saturation storage capacity, defined as the thin film of water that must wet tree surfaces before flow begins, is the most important variable influencing rainfall interception processes. Surface storage capacity is known to vary widely among tree species, but it is little studied. This research measured surface storage capacities of 20 urban tree species in a rainfall simulator. The measurement system included a rainfall simulator, digital balance, digital camera, and computer. Eight samples were randomly collected from each tree species. Twelve rainfall intensities (3.5-139.5 mm h) were simulated. Leaf-on and leaf-off simulations were conducted for deciduous species. Stem and foliar surface areas were estimated using an image analysis method. Results indicated that surface storage capacities varied threefold among tree species, 0.59 mm for crape myrtle ( L.) and 1.81 mm for blue spruce ( Engelm.). The mean value across all species was 0.86 mm (0.11 mm SD). To illustrate application of the storage values, interception was simulated and compared across species for a 40-yr period with different rainfall intensities and durations. By quantifying the potential for different tree species to intercept rainfall under a variety of meteorological conditions, this study provides new knowledge that is fundamental to validating the cost-effectiveness of urban forestry as a green infrastructure strategy and designing functional plantings. PMID:26828174

  1. No evidence for consistent long-term growth stimulation of 13 tropical tree species: results from tree-ring analysis.

    PubMed

    Groenendijk, Peter; van der Sleen, Peter; Vlam, Mart; Bunyavejchewin, Sarayudh; Bongers, Frans; Zuidema, Pieter A

    2015-10-01

    The important role of tropical forests in the global carbon cycle makes it imperative to assess changes in their carbon dynamics for accurate projections of future climate-vegetation feedbacks. Forest monitoring studies conducted over the past decades have found evidence for both increasing and decreasing growth rates of tropical forest trees. The limited duration of these studies restrained analyses to decadal scales, and it is still unclear whether growth changes occurred over longer time scales, as would be expected if CO2 -fertilization stimulated tree growth. Furthermore, studies have so far dealt with changes in biomass gain at forest-stand level, but insights into species-specific growth changes - that ultimately determine community-level responses - are lacking. Here, we analyse species-specific growth changes on a centennial scale, using growth data from tree-ring analysis for 13 tree species (~1300 trees), from three sites distributed across the tropics. We used an established (regional curve standardization) and a new (size-class isolation) growth-trend detection method and explicitly assessed the influence of biases on the trend detection. In addition, we assessed whether aggregated trends were present within and across study sites. We found evidence for decreasing growth rates over time for 8-10 species, whereas increases were noted for two species and one showed no trend. Additionally, we found evidence for weak aggregated growth decreases at the site in Thailand and when analysing all sites simultaneously. The observed growth reductions suggest deteriorating growth conditions, perhaps due to warming. However, other causes cannot be excluded, such as recovery from large-scale disturbances or changing forest dynamics. Our findings contrast growth patterns that would be expected if elevated CO2 would stimulate tree growth. These results suggest that commonly assumed growth increases of tropical forests may not occur, which could lead to erroneous

  2. Species tree estimation for a deep phylogenetic divergence in the New World monkeys (Primates: Platyrrhini).

    PubMed

    Perez, S Ivan; Klaczko, Julia; dos Reis, Sérgio F

    2012-11-01

    The estimation of a robust phylogeny is a necessary first step in understanding the biological diversification of the platyrrhines. Although the most recent phylogenies are generally robust, they differ from one another in the relationship between Aotus and other genera as well as in the relationship between Pitheciidae and other families. Here, we used coding and non-coding sequences to infer the species tree and embedded gene trees of the platyrrhine genera using the Bayesian Markov chain Monte Carlo method for the multispecies coalescent (*BEAST) for the first time and to compared the results with those of a Bayesian concatenated phylogenetic analysis. Our species tree, based on all available sequences, shows a closer phylogenetic relationship between Atelidae and Cebidae and a closer relationship between Aotus and the Cebidae clade. The posterior probabilities are lower for these conflictive tree nodes compared to those in the concatenated analysis; this finding could be explained by some gene trees showing no concordant topologies between Aotus and the other genera. Moreover, the topology of our species tree also differs from the findings of previous molecular and morphological studies regarding the position of Aotus. The existence of discrepancies between morphological data, gene trees and the species tree is widely reported and can be related to processes such as incomplete lineage sorting or selection. Although these processes are common in species trees with low divergence, they can also occur in species trees with deep and rapid divergence. The sources of the inconsistency of morphological and molecular traits with the species tree could be a main focus of further research on platyrrhines. PMID:22841656

  3. Phylogenomic species tree estimation in the presence of incomplete lineage sorting and horizontal gene transfer

    PubMed Central

    2015-01-01

    Background Species tree estimation is challenged by gene tree heterogeneity resulting from biological processes such as duplication and loss, hybridization, incomplete lineage sorting (ILS), and horizontal gene transfer (HGT). Mathematical theory about reconstructing species trees in the presence of HGT alone or ILS alone suggests that quartet-based species tree methods (known to be statistically consistent under ILS, or under bounded amounts of HGT) might be effective techniques for estimating species trees when both HGT and ILS are present. Results We evaluated several publicly available coalescent-based methods and concatenation under maximum likelihood on simulated datasets with moderate ILS and varying levels of HGT. Our study shows that two quartet-based species tree estimation methods (ASTRAL-2 and weighted Quartets MaxCut) are both highly accurate, even on datasets with high rates of HGT. In contrast, although NJst and concatenation using maximum likelihood are highly accurate under low HGT, they are less robust to high HGT rates. Conclusion Our study shows that quartet-based species-tree estimation methods can be highly accurate under the presence of both HGT and ILS. The study suggests the possibility that some quartet-based methods might be statistically consistent under phylogenomic models of gene tree heterogeneity with both HGT and ILS. PMID:26450506

  4. Seasonal variations of isoprene emissions from five oak tree species in East Asia

    NASA Astrophysics Data System (ADS)

    Lim, Yong-Jae; Armendariz, Al; Son, Youn-Suk; Kim, Jo-Chun

    2011-04-01

    Emissions of biogenic volatile organic compounds (BVOC) from trees can enhance the photochemical production of tropospheric ozone. Isoprene is one of the most environmentally important BVOCs, since its emission rate from certain tree species can be high and its chemical structure gives it high ozone forming potential. Understanding of isoprene emission rates from many tree species is limited, including influences of tree age, season, and other factors. Five oak species were studied which represent approximately 85 percent of the deciduous trees in South Korean forests. In general, there were obvious seasonal variations of isoprene emissions from five oak trees. Especially, Quercus aliena B. and Quercus mongolica F showed substantial seasonal variations of isoprene emissions; However, Quercus serrata T. and Quercus acutissima C. generally did not. It was found that Q. serrata T. showed the highest isoprene emission rates among the species tested (up to 130.5 μgC gdw -1 h -1) and its emission rates were highest during spring followed by summer and fall. The emission rates from two ( Q. acutissima C., Quercus variabilis B.) of the other tested oak species were lower by more than 3 orders of magnitude. Besides, two oak species, Q. aliena B. and Q. mongolica F. were chosen to determine the effect of tree age on isoprene emissions. Trees at the age of 21˜30 years had significantly higher isoprene emission rates than those at the age of 41˜50.

  5. Alienation Incident.

    ERIC Educational Resources Information Center

    Wasserman, Louis

    1979-01-01

    Critiques Marxian "cures" for alienation as discussed in Karl Marx's "Economic and Philosophical Manuscripts." Also traces the activity of a former student who joined the revolution in Cuba. Journal available from 7 Harwood Drive, Amherst, New York, 14226. (KC)

  6. Salinity and temperature tolerance of an emergent alien species, the Amazon fish Astronotus ocellatus

    USGS Publications Warehouse

    Gutierrel, Silvia M M; Schofield, Pam; Prodocimo, Viviane

    2016-01-01

    Astronotus ocellatus (oscar), is native to the Amazon basin and, although it has been introduced to many countries, little is known regarding its tolerances for salinity and temperature. In this report, we provide data on the tolerance of A. ocellatus to abrupt and gradual changes in salinity, its high and low temperature tolerance, and information on how salinity, temperature, and fish size interact to affect survival. Fish were able to survive abrupt transfer to salinities as high as 16 ppt with no mortality. When salinity change was gradual (2 ppt/day), fish in the warm-temperature experiment (28°C) survived longer than fish in the cool-temperature experiment (18°C). Larger fish survived longer than smaller ones at the higher salinities when the temperature was warm, but when the temperature was cool fish size had little effect on survival. In the temperature-tolerance experiments, fish survived from 9 to 41°C for short periods of time. Overall, the species showed a wide range of temperature and salinity tolerance. Thus, in spite of the tropical freshwater origin of this species, physiological stress is not likely to hinder its dispersal to brackish waters, especially when temperatures are warm.

  7. Macroparasite fauna of alien grey squirrels (Sciurus carolinensis): composition, variability and implications for native species.

    PubMed

    Romeo, Claudia; Wauters, Lucas A; Ferrari, Nicola; Lanfranchi, Paolo; Martinoli, Adriano; Pisanu, Benoît; Preatoni, Damiano G; Saino, Nicola

    2014-01-01

    Introduced hosts populations may benefit of an "enemy release" through impoverishment of parasite communities made of both few imported species and few acquired local ones. Moreover, closely related competing native hosts can be affected by acquiring introduced taxa (spillover) and by increased transmission risk of native parasites (spillback). We determined the macroparasite fauna of invasive grey squirrels (Sciurus carolinensis) in Italy to detect any diversity loss, introduction of novel parasites or acquisition of local ones, and analysed variation in parasite burdens to identify factors that may increase transmission risk for native red squirrels (S. vulgaris). Based on 277 grey squirrels sampled from 7 populations characterised by different time scales in introduction events, we identified 7 gastro-intestinal helminths and 4 parasite arthropods. Parasite richness is lower than in grey squirrel's native range and independent from introduction time lags. The most common parasites are Nearctic nematodes Strongyloides robustus (prevalence: 56.6%) and Trichostrongylus calcaratus (6.5%), red squirrel flea Ceratophyllus sciurorum (26.0%) and Holarctic sucking louse Neohaematopinus sciuri (17.7%). All other parasites are European or cosmopolitan species with prevalence below 5%. S. robustus abundance is positively affected by host density and body mass, C. sciurorum abundance increases with host density and varies with seasons. Overall, we show that grey squirrels in Italy may benefit of an enemy release, and both spillback and spillover processes towards native red squirrels may occur. PMID:24505348

  8. Border control for stowaway alien species should be prioritised based on variations in establishment debt.

    PubMed

    Faulkner, Katelyn T; Robertson, Mark P; Rouget, Mathieu; Wilson, John R U

    2016-09-15

    Border control is one of the major approaches used by countries to limit the number of organisms introduced as stowaways. However, it is not feasible to inspect all passengers, cargo and vehicles entering a country, and so efforts need to be prioritised. Here we use South Africa as a case study to assess, based on tourism and trade data and climate matching techniques, the number of stowaway species that might be introduced ('colonisation pressure') and the likelihood that once introduced, these organisms will establish ('likelihood of establishment'). These results were used to explore how the number of species that are likely to establish ('establishment debt') varies across donor regions and seasons. A simple theoretical model was then used to compare four strategies for prioritising border control inspections: no prioritisation; based on colonisation pressure; based on likelihood of establishment; and based on both colonisation pressure and likelihood of establishment. Establishment debt was greatest in southern hemisphere spring and autumn when South Africa is climatically similar to northern hemisphere countries with which there are strong, consistent trade and tourism links (i.e. colonisation pressure varied little seasonally, but likelihood of establishment did vary across the seasons). Prioritising inspections based on both colonisation pressure and the likelihood of establishment was clearly the most effective strategy, with this strategy detecting at least 6% more potential invaders than the other strategies. While there are many practical limitations to the implementation of such prioritised inspection strategies, the results highlight the importance of national and regional studies of establishment debt. PMID:27240206

  9. Macroparasite Fauna of Alien Grey Squirrels (Sciurus carolinensis): Composition, Variability and Implications for Native Species

    PubMed Central

    Romeo, Claudia; Wauters, Lucas A.; Ferrari, Nicola; Lanfranchi, Paolo; Martinoli, Adriano; Pisanu, Benoît; Preatoni, Damiano G.; Saino, Nicola

    2014-01-01

    Introduced hosts populations may benefit of an "enemy release" through impoverishment of parasite communities made of both few imported species and few acquired local ones. Moreover, closely related competing native hosts can be affected by acquiring introduced taxa (spillover) and by increased transmission risk of native parasites (spillback). We determined the macroparasite fauna of invasive grey squirrels (Sciurus carolinensis) in Italy to detect any diversity loss, introduction of novel parasites or acquisition of local ones, and analysed variation in parasite burdens to identify factors that may increase transmission risk for native red squirrels (S. vulgaris). Based on 277 grey squirrels sampled from 7 populations characterised by different time scales in introduction events, we identified 7 gastro-intestinal helminths and 4 parasite arthropods. Parasite richness is lower than in grey squirrel's native range and independent from introduction time lags. The most common parasites are Nearctic nematodes Strongyloides robustus (prevalence: 56.6%) and Trichostrongylus calcaratus (6.5%), red squirrel flea Ceratophyllus sciurorum (26.0%) and Holarctic sucking louse Neohaematopinus sciuri (17.7%). All other parasites are European or cosmopolitan species with prevalence below 5%. S. robustus abundance is positively affected by host density and body mass, C. sciurorum abundance increases with host density and varies with seasons. Overall, we show that grey squirrels in Italy may benefit of an enemy release, and both spillback and spillover processes towards native red squirrels may occur. PMID:24505348

  10. Soil magnetic susceptibility reflects soil moisture regimes and the adaptability of tree species to these regimes

    USGS Publications Warehouse

    Wang, J.-S.; Grimley, D.A.; Xu, C.; Dawson, J.O.

    2008-01-01

    Flooded, saturated or poorly drained soils are frequently anaerobic, leading to dissolution of the strongly magnetic minerals, magnetite and maghemite, and a corresponding decrease in soil magnetic susceptibility (MS). In this study of five temperate deciduous forests in east-central Illinois, USA, mean surface soil MS was significantly higher adjacent to upland tree species (31 ?? 10-5 SI) than adjacent to floodplain or lowland tree species (17 ?? 10-5 SI), when comparing regional soils with similar parent material of loessal silt. Although the sites differ in average soil MS for each tree species, the relative order of soil MS means for associated tree species at different locations is similar. Lowland tree species, Celtis occidentalis L., Ulmus americana L., Acer saccharinum L., Carya laciniosa (Michx. f.) Loud., and Fraxinus pennsylvanica Marsh. were associated with the lowest measured soil MS mean values overall and at each site. Tree species' flood tolerance rankings increased significantly, as soil MS values declined, the published rankings having significant correlations with soil MS values for the same species groups. The three published classifications of tree species' flood tolerance were significantly correlated with associated soil MS values at all sites, but most strongly at Allerton Park, the site with the widest range of soil drainage classes and MS values. Using soil MS measurements in forests with soil parent material containing similar initial levels of strongly magnetic minerals can provide a simple, rapid and quantitative method to classify soils according to hydric regimes, including dry conditions, and associated plant composition. Soil MS values thus have the capacity to quantify the continuum of hydric tolerances of tree species and guide tree species selection for reforestation. ?? 2007 Elsevier B.V. All rights reserved.

  11. Species-environment relationships and vegetation patterns: Effects of spatial scale and tree life-stage

    USGS Publications Warehouse

    Stohlgren, T.J.; Bachand, R.R.; Onami, Y.; Binkley, D.

    1998-01-01

    Do relationships between species and environmental gradients strengthen or weaken with tree life-stage (i.e., small seedlings, large seedlings, saplings, and mature trees)? Strengthened relationships may lead to distinct forest type boundaries, or weakening connections could lead to gradual ecotones and heterogeneous forest landscapes. We quantified the changes in forest dominance (basal area of tree species by life-stage) and environmental factors (elevation, slope, aspect, intercepted photosynthetically active radiation (PAR), summer soil moisture, and soil depth and texture) across 14 forest ecotones (n = 584, 10 m x 10 m plots) in Rocky Mountain National Park, Colorado, U.S.A. Local, ecotone-specific species-environment relationships, based on multiple regression techniques, generally strengthened from the small seedling stage (multiple R2 ranged from 0.00 to 0.26) to the tree stage (multiple R2 ranged from 0.20 to 0.61). At the landscape scale, combined canonical correspondence analysis (CCA) among species and for all tree life-stages suggested that the seedlings of most species became established in lower-elevation, drier sites than where mature trees of the same species dominated. However, conflicting evidence showed that species-environment relationships may weaken with tree life-stage. Seedlings were only found in a subset of plots (habitats) occupied by mature trees of the same species. At the landscape scale, CCA results showed that species-environment relationships weakened somewhat from the small seedling stage (86.4% of the variance explained by the first two axes) to the tree stage (76.6% of variance explained). The basal area of tree species co-occurring with Pinus contorta Doug. ex. Loud declined more gradually than P. contorta basal area declined across ecotones, resulting in less-distinct forest type boundaries. We conclude that broad, gradual ecotones and heterogeneous forest landscapes are created and maintained by: (1) sporadic establishment

  12. Neighbour Origin and Ploidy Level Drive Impact of an Alien Invasive Plant Species in a Competitive Environment

    PubMed Central

    Sun, Yan; Müller-Schärer, Heinz; Schaffner, Urs

    2016-01-01

    Our understanding of the potential mechanisms driving the spread and naturalization of alien plant species has increased over the past decades, but specific knowledge on the factors contributing to their increased impact in the introduced range is still urgently needed. The native European plant Centaurea stoebe occurs as two cytotypes with different life histories (monocarpic diploids, allo-polycarpic tetraploids). However, only tetraploids have been found in its introduced range in North America, where C. stoebe has become a most prominent plant invader. Here, we focus on the ploidy level of C. stoebe and origin of neighbouring community in explaining the high impact during the invasion of new sites in the introduced range. We conducted a mesocosm experiment under open-field conditions with the diploid (EU2x) and tetraploid (EU4x) cytotype of Centaurea stoebe from its native European (EU) range, and with the invasive tetraploid (NA4x) cytotype from the introduced North American (NA) range in competition with EU (old) or NA (new) neighbouring plant communities. In the presence of competition, the biomass of EU neighbouring community was reduced to a comparable level by all three geo-cytotypes of C. stoebe. In contrast, the biomass of the NA neighbouring community was reduced beyond when competing with tetraploid, but not with diploid C. stoebe. The fact that the biomass of all three geo-cytotypes of C. stoebe was correlated with the biomass of the EU neighbouring community, but not with that of the NA neighbouring community suggests that different mechanisms underlie the competitive interactions between C. stoebe and its old vs. new neighbouring communities, such as competition for the same limiting resources at home vs competition through novel allelo-chemicals or differential resource uptake strategies in the introduced range. We therefore caution to simply use the ecosystem impact assessed at home to predict impact in the introduced range. PMID:27203687

  13. Neighbour Origin and Ploidy Level Drive Impact of an Alien Invasive Plant Species in a Competitive Environment.

    PubMed

    Sun, Yan; Müller-Schärer, Heinz; Schaffner, Urs

    2016-01-01

    Our understanding of the potential mechanisms driving the spread and naturalization of alien plant species has increased over the past decades, but specific knowledge on the factors contributing to their increased impact in the introduced range is still urgently needed. The native European plant Centaurea stoebe occurs as two cytotypes with different life histories (monocarpic diploids, allo-polycarpic tetraploids). However, only tetraploids have been found in its introduced range in North America, where C. stoebe has become a most prominent plant invader. Here, we focus on the ploidy level of C. stoebe and origin of neighbouring community in explaining the high impact during the invasion of new sites in the introduced range. We conducted a mesocosm experiment under open-field conditions with the diploid (EU2x) and tetraploid (EU4x) cytotype of Centaurea stoebe from its native European (EU) range, and with the invasive tetraploid (NA4x) cytotype from the introduced North American (NA) range in competition with EU (old) or NA (new) neighbouring plant communities. In the presence of competition, the biomass of EU neighbouring community was reduced to a comparable level by all three geo-cytotypes of C. stoebe. In contrast, the biomass of the NA neighbouring community was reduced beyond when competing with tetraploid, but not with diploid C. stoebe. The fact that the biomass of all three geo-cytotypes of C. stoebe was correlated with the biomass of the EU neighbouring community, but not with that of the NA neighbouring community suggests that different mechanisms underlie the competitive interactions between C. stoebe and its old vs. new neighbouring communities, such as competition for the same limiting resources at home vs competition through novel allelo-chemicals or differential resource uptake strategies in the introduced range. We therefore caution to simply use the ecosystem impact assessed at home to predict impact in the introduced range. PMID:27203687

  14. Lack of sex-specific movement patterns in an alien species at its invasion front - consequences for invasion speed.

    PubMed

    Herfindal, Ivar; Melis, Claudia; Åhlén, Per-Arne; Dahl, Fredrik

    2016-08-01

    Efficient targeting of actions to reduce the spread of invasive alien species relies on understanding the spatial, temporal, and individual variation of movement, in particular related to dispersal. Such patterns may differ between individuals at the invasion front compared to individuals in established and dense populations due to differences in environmental and ecological conditions such as abundance of conspecifics or sex-specific dispersal affecting the encounter rate of potential mates. We assessed seasonal and diurnal variation in movement pattern (step length and turning angle) of adult male and female raccoon dog at their invasion front in northern Sweden using data from Global Positioning System (GPS)-marked adult individuals and assessed whether male and female raccoon dog differed in their movement behavior. There were few consistent sex differences in movement. The rate of dispersal was rather similar over the months, suggesting that both male and female raccoon dog disperse during most of the year, but with higher speed during spring and summer. There were diurnal movement patterns in both sexes with more directional and faster movement during the dark hours. However, the short summer nights may limit such movement patterns, and long-distance displacement was best explained by fine-scale movement patterns from 18:00 to 05:00, rather than by movement patterns only from twilight and night. Simulation of dispersing raccoon dogs suggested a higher frequency of male-female encounters that were further away from the source population for the empirical data compared to a scenario with sex differences in movement pattern. The lack of sex differences in movement pattern at the invasion front results in an increased likelihood for reproductive events far from the source population. Animals outside the source population should be considered potential reproducing individuals, and a high effort to capture such individuals is needed throughout the year to prevent

  15. Tissue culture and top-fruit tree species.

    PubMed

    Ochatt, S J; Davey, M R; Power, J B

    1990-01-01

    The commercial cultivation of rosaceous fruit trees (e.g., pear, apple, cherry, peach, plum) relies heavily upon the quality and performance of the rootstocks. This is even more the case now that self-rooted scions produce larger trees with a longer juvenile phase (1). It would, therefore, be of special interest for the fruit breeder to have general purpose rootstocks with a wide ecophysiological adaptation and high compatibility coupled with early cropping. In addition, many of the older and highly adapted scion varieties of fruit trees could benefit greatly from the introduction of stable, yet minor changes in their genome. Fruit trees are generally highly heterozygous, outbreeding, and thus are asexually propagated (see Chapter 10 , this vol.). Consequently, genetic improvement is likely to be based on protoplast technology, and achieved mainly through somatic methods, such as somaclonal variation or somatic hybridization. PMID:21390607

  16. Designing Mixed Species Tree Plantations for the Tropics: Balancing Ecological Attributes of Species with Landholder Preferences in the Philippines

    PubMed Central

    Nguyen, Huong; Lamb, David; Herbohn, John; Firn, Jennifer

    2014-01-01

    A mixed species reforestation program known as the Rainforestation Farming system was undertaken in the Philippines to develop forms of farm forestry more suitable for smallholders than the simple monocultural plantations commonly used then. In this study, we describe the subsequent changes in stand structure and floristic composition of these plantations in order to learn from the experience and develop improved prescriptions for reforestation systems likely to be attractive to smallholders. We investigated stands aged from 6 to 11 years old on three successive occasions over a 6 year period. We found the number of species originally present in the plots as trees >5 cm dbh decreased from an initial total of 76 species to 65 species at the end of study period. But, at the same time, some new species reached the size class threshold and were recruited into the canopy layer. There was a substantial decline in tree density from an estimated stocking of about 5000 trees per ha at the time of planting to 1380 trees per ha at the time of the first measurement; the density declined by a further 4.9% per year. Changes in composition and stand structure were indicated by a marked shift in the Importance Value Index of species. Over six years, shade-intolerant species became less important and the native shade-tolerant species (often Dipterocarps) increased in importance. Based on how the Rainforestation Farming plantations developed in these early years, we suggest that mixed-species plantations elsewhere in the humid tropics should be around 1000 trees per ha or less, that the proportion of fast growing (and hence early maturing) trees should be about 30–40% of this initial density and that any fruit tree component should only be planted on the plantation margin where more light and space are available for crowns to develop. PMID:24751720

  17. Designing mixed species tree plantations for the tropics: balancing ecological attributes of species with landholder preferences in the Philippines.

    PubMed

    Nguyen, Huong; Lamb, David; Herbohn, John; Firn, Jennifer

    2014-01-01

    A mixed species reforestation program known as the Rainforestation Farming system was undertaken in the Philippines to develop forms of farm forestry more suitable for smallholders than the simple monocultural plantations commonly used then. In this study, we describe the subsequent changes in stand structure and floristic composition of these plantations in order to learn from the experience and develop improved prescriptions for reforestation systems likely to be attractive to smallholders. We investigated stands aged from 6 to 11 years old on three successive occasions over a 6 year period. We found the number of species originally present in the plots as trees >5 cm dbh decreased from an initial total of 76 species to 65 species at the end of study period. But, at the same time, some new species reached the size class threshold and were recruited into the canopy layer. There was a substantial decline in tree density from an estimated stocking of about 5000 trees per ha at the time of planting to 1380 trees per ha at the time of the first measurement; the density declined by a further 4.9% per year. Changes in composition and stand structure were indicated by a marked shift in the Importance Value Index of species. Over six years, shade-intolerant species became less important and the native shade-tolerant species (often Dipterocarps) increased in importance. Based on how the Rainforestation Farming plantations developed in these early years, we suggest that mixed-species plantations elsewhere in the humid tropics should be around 1000 trees per ha or less, that the proportion of fast growing (and hence early maturing) trees should be about 30-40% of this initial density and that any fruit tree component should only be planted on the plantation margin where more light and space are available for crowns to develop. PMID:24751720

  18. CpDNA-based species identification and phylogeography: application to African tropical tree species.

    PubMed

    Duminil, J; Heuertz, M; Doucet, J-L; Bourland, N; Cruaud, C; Gavory, F; Doumenge, C; Navascués, M; Hardy, O J

    2010-12-01

    Despite the importance of the African tropical rainforests as a hotspot of biodiversity, their history and the processes that have structured their biodiversity are understood poorly. With respect to past demographic processes, new insights can be gained through characterizing the distribution of genetic diversity. However, few studies of this type have been conducted in Central Africa, where the identification of species in the field can be difficult. We examine here the distribution of chloroplast DNA (cpDNA) diversity in Lower Guinea in two tree species that are difficult to distinguish, Erythrophleum ivorense and Erythrophleum suaveolens (Fabaceae). By using a blind-sampling approach and comparing molecular and morphological markers, we first identified retrospectively all sampled individuals and determined the limits of the distribution of each species. We then performed a phylogeographic study using the same genetic data set. The two species displayed essentially parapatric distributions that were correlated well with the rainfall gradient, which indicated different ecological requirements. In addition, a phylogeographic structure was found for E. suaveolens and, for both species, substantially higher levels of diversity and allelic endemism were observed in the south (Gabon) than in the north (Cameroon) of the Lower Guinea region. This finding indicated different histories of population demographics for the two species, which might reflect different responses to Quaternary climate changes. We suggest that a recent period of forest perturbation, which might have been caused by humans, favoured the spread of these two species and that their poor recruitment at present results from natural succession in their forest formations. PMID:21091558

  19. Temporal dynamics of arthropods on six tree species in dry woodlands on the Caribbean Island of Puerto Rico.

    PubMed

    Beltrán, William; Wunderle, Joseph M

    2014-01-01

    The seasonal dynamics of foliage arthropod populations are poorly studied in tropical dry forests despite the importance of these studies for understanding arthropod population responses to environmental change. We monitored the abundance, temporal distributions, and body size of arthropods in five naturalized alien and one native tree species to characterize arthropod seasonality in dry novel Prosopis-Leucaena woodlands in Puerto Rico. A branch clipping method was used monthly to sample foliage arthropod abundance over 39 mo. Seasonal patterns of rainfall and abundance within various arthropod taxa were highly variable from year to year. Abundance for most taxa did not show significant seasonality over the 3 yr, although most taxa had abundance peaks each year. However, Homoptera displayed high seasonality with significant temporal aggregations in each year. Formicidae, Orthoptera, and Coleoptera showed high variation in abundance between wet and dry periods, whereas Hemiptera were consistently more abundant in the wet period. Seasonal differences in mean abundance were found only in a few taxa on Tamarindus indica L., Bucida buceras L., Pithecellobium dulce, and (Roxburgh) Benth. Mean arthropod abundance varied among tree species, with highest numbers on Prosopis juliflora, (Swartz) De Candolle, Pi. dulce, Leucaena leucocephala, and (Lamarck) de Wit. Abundance of Araneae, Orthoptera, Coleoptera, Lepidoptera larvae, and all arthropods showed weak relationships with one or more climatic variables (rainfall, maximum temperature, or relative humidity). Body size of arthropods was usually largest during the dry periods. Overall, total foliage arthropod abundance showed no consistent seasonality among years, which may become a more common trend in dry forests and woodlands in the Caribbean if seasonality of rainfall becomes less predictable. PMID:25502036

  20. Temporal Dynamics of Arthropods on Six Tree Species in Dry Woodlands on the Caribbean Island of Puerto Rico

    PubMed Central

    Beltrán, William; Wunderle, Joseph M.

    2014-01-01

    The seasonal dynamics of foliage arthropod populations are poorly studied in tropical dry forests despite the importance of these studies for understanding arthropod population responses to environmental change. We monitored the abundance, temporal distributions, and body size of arthropods in five naturalized alien and one native tree species to characterize arthropod seasonality in dry novel Prosopis–Leucaena woodlands in Puerto Rico. A branch clipping method was used monthly to sample foliage arthropod abundance over 39 mo. Seasonal patterns of rainfall and abundance within various arthropod taxa were highly variable from year to year. Abundance for most taxa did not show significant seasonality over the 3 yr, although most taxa had abundance peaks each year. However, Homoptera displayed high seasonality with significant temporal aggregations in each year. Formicidae, Orthoptera, and Coleoptera showed high variation in abundance between wet and dry periods, whereas Hemiptera were consistently more abundant in the wet period. Seasonal differences in mean abundance were found only in a few taxa on Tamarindus indica L., Bucida buceras L., Pithecellobium dulce, and (Roxburgh) Benth. Mean arthropod abundance varied among tree species, with highest numbers on Prosopis juliflora, (Swartz) De Candolle, Pi. dulce, Leucaena leucocephala, and (Lamarck) de Wit. Abundance of Araneae, Orthoptera, Coleoptera, Lepidoptera larvae, and all arthropods showed weak relationships with one or more climatic variables (rainfall, maximum temperature, or relative humidity). Body size of arthropods was usually largest during the dry periods. Overall, total foliage arthropod abundance showed no consistent seasonality among years, which may become a more common trend in dry forests and woodlands in the Caribbean if seasonality of rainfall becomes less predictable. PMID:25502036

  1. Concatenation and Species Tree Methods Exhibit Statistically Indistinguishable Accuracy under a Range of Simulated Conditions

    PubMed Central

    Tonini, João; Moore, Andrew; Stern, David; Shcheglovitova, Maryia; Ortí, Guillermo

    2015-01-01

    Phylogeneticists have long understood that several biological processes can cause a gene tree to disagree with its species tree. In recent years, molecular phylogeneticists have increasingly foregone traditional supermatrix approaches in favor of species tree methods that account for one such source of error, incomplete lineage sorting (ILS). While gene tree-species tree discordance no doubt poses a significant challenge to phylogenetic inference with molecular data, researchers have only recently begun to systematically evaluate the relative accuracy of traditional and ILS-sensitive methods. Here, we report on simulations demonstrating that concatenation can perform as well or better than methods that attempt to account for sources of error introduced by ILS. Based on these and similar results from other researchers, we argue that concatenation remains a useful component of the phylogeneticist’s toolbox and highlight that phylogeneticists should continue to make explicit comparisons of results produced by contemporaneous and classical methods. PMID:25901289

  2. Tree diversity and species identity effects on soil fungi, protists and animals are context dependent.

    PubMed

    Tedersoo, Leho; Bahram, Mohammad; Cajthaml, Tomáš; Põlme, Sergei; Hiiesalu, Indrek; Anslan, Sten; Harend, Helery; Buegger, Franz; Pritsch, Karin; Koricheva, Julia; Abarenkov, Kessy

    2016-02-01

    Plant species richness and the presence of certain influential species (sampling effect) drive the stability and functionality of ecosystems as well as primary production and biomass of consumers. However, little is known about these floristic effects on richness and community composition of soil biota in forest habitats owing to methodological constraints. We developed a DNA metabarcoding approach to identify the major eukaryote groups directly from soil with roughly species-level resolution. Using this method, we examined the effects of tree diversity and individual tree species on soil microbial biomass and taxonomic richness of soil biota in two experimental study systems in Finland and Estonia and accounted for edaphic variables and spatial autocorrelation. Our analyses revealed that the effects of tree diversity and individual species on soil biota are largely context dependent. Multiple regression and structural equation modelling suggested that biomass, soil pH, nutrients and tree species directly affect richness of different taxonomic groups. The community composition of most soil organisms was strongly correlated due to similar response to environmental predictors rather than causal relationships. On a local scale, soil resources and tree species have stronger effect on diversity of soil biota than tree species richness per se. PMID:26172210

  3. Introgression of chromosome segments from multiple alien species in wheat breeding lines with wheat streak mosaic virus resistance.

    PubMed

    Ali, N; Heslop-Harrison, Js Pat; Ahmad, H; Graybosch, R A; Hein, G L; Schwarzacher, T

    2016-08-01

    Pyramiding of alien-derived Wheat streak mosaic virus (WSMV) resistance and resistance enhancing genes in wheat is a cost-effective and environmentally safe strategy for disease control. PCR-based markers and cytogenetic analysis with genomic in situ hybridisation were applied to identify alien chromatin in four genetically diverse populations of wheat (Triticum aestivum) lines incorporating chromosome segments from Thinopyrum intermedium and Secale cereale (rye). Out of 20 experimental lines, 10 carried Th. intermedium chromatin as T4DL*4Ai#2S translocations, while, unexpectedly, 7 lines were positive for alien chromatin (Th. intermedium or rye) on chromosome 1B. The newly described rye 1RS chromatin, transmitted from early in the pedigree, was associated with enhanced WSMV resistance. Under field conditions, the 1RS chromatin alone showed some resistance, while together with the Th. intermedium 4Ai#2S offered superior resistance to that demonstrated by the known resistant cultivar Mace. Most alien wheat lines carry whole chromosome arms, and it is notable that these lines showed intra-arm recombination within the 1BS arm. The translocation breakpoints between 1BS and alien chromatin fell in three categories: (i) at or near to the centromere, (ii) intercalary between markers UL-Thin5 and Xgwm1130 and (iii) towards the telomere between Xgwm0911 and Xbarc194. Labelled genomic Th. intermedium DNA hybridised to the rye 1RS chromatin under high stringency conditions, indicating the presence of shared tandem repeats among the cereals. The novel small alien fragments may explain the difficulty in developing well-adapted lines carrying Wsm1 despite improved tolerance to the virus. The results will facilitate directed chromosome engineering producing agronomically desirable WSMV-resistant germplasm. PMID:27245423

  4. Leapfrogging of tree species provenances? Interaction of microclimate and genetics on upward shifts in tree species' range limits

    NASA Astrophysics Data System (ADS)

    Reinhardt, K.; Castanha, C.; Germino, M. J.; Kueppers, L. M.

    2011-12-01

    The elevation limit of tree growth (alpine treeline) is considered to be constrained by environmental (i.e., thermal) and genetic (i.e., inability to adapt to climatic conditions) limitations to growth. Warming conditions due to climate change are predicted to cause upward shifts in the elevation of alpine treelines, through relief of cold-induced physiological limitations on seedling recruitment beyond current treeline boundaries. To determine how genetics and climate may interact to affect seedling establishment, we transplanted recently germinated seedlings from high- and low-elevation provenances (HI and LO, respectively) of Pinus flexilis in common gardens arrayed along an elevation and canopy gradient from subalpine forest into the alpine zone at Niwot Ridge, CO. We compared differences in microclimate and seedling ecophysiology among sites and between provenances. During the first summer of growth, frequently cloudy skies resulted in similar solar radiation incidence and air and soil temperatures among sites, despite nearly a 500 m-span in elevation across all sites. Preliminary findings suggest that survival of seedlings was similar between the lowest and highest elevations, with greater survival of LO (60%) compared to HI (40%) seedlings at each of these sites. Photosynthesis, carbon balance (photosynthesis/respiration), and conductance increased more than 2X with elevation for both provenances, and were 35-77% greater in LO seedlings compared to HI seedlings. There were no differences in dark-adapted chlorophyll fluorescence (Fv/Fm) among sites or between provenances. However, in a common-garden study at low elevation, we observed no differences in carbon or water relations between two naturally-germinated mitochondrial haplotypes of P. flexilis (of narrow and wide-ranging distributions). We did observe water-related thresholds on seedling carbon balance and survival that occurred when soil volumetric water content dropped below 10% and seedling water

  5. Coordination between water transport capacity, biomass growth, metabolic scaling and species stature in co-occurring shrub and tree species.

    PubMed

    Smith, Duncan D; Sperry, John S

    2014-12-01

    The significance of xylem function and metabolic scaling theory begins from the idea that water transport is strongly coupled to growth rate. At the same time, coordination of water transport and growth seemingly should differ between plant functional types. We evaluated the relationships between water transport, growth and species stature in six species of co-occurring trees and shrubs. Within species, a strong proportionality between plant hydraulic conductance (K), sap flow (Q) and shoot biomass growth (G) was generally supported. Across species, however, trees grew more for a given K or Q than shrubs, indicating greater growth-based water-use efficiency (WUE) in trees. Trees also showed slower decline in relative growth rate (RGR) than shrubs, equivalent to a steeper G by mass (M) scaling exponent in trees (0.77-0.98). The K and Q by M scaling exponents were common across all species (0.80, 0.82), suggesting that the steeper G scaling in trees reflects a size-dependent increase in their growth-based WUE. The common K and Q by M exponents were statistically consistent with the 0.75 of ideal scaling theory. A model based upon xylem anatomy and branching architecture consistently predicted the observed K by M scaling exponents but only when deviations from ideal symmetric branching were incorporated. PMID:25041417

  6. SIMULATION OF OZONE EFFECTS ON EIGHT TREE SPECIES AT SHENANDOAH NATIONAL PARK

    EPA Science Inventory

    As part of an assessment of potential effects of air pollutants on the vegetation of Shenandoah National Park (SHEN), we simulated the growth of eight important tree species using TREGRO, a mechanistic model of individual tree growth. Published TREGRO parameters for black cherry...

  7. Assessing the potential of native tree species for carbon sequestration forestry in Northeast China.

    PubMed

    Thomas, S C; Malczewski, G; Saprunoff, M

    2007-11-01

    Although the native forests of China are exceptionally diverse, only a small number of tree species have been widely utilized in forest plantations and reforestation efforts. We used dendrochronological sampling methods to assess the potential growth and carbon sequestration of native tree species in Jilin Province, Northeast China. Trees were sampled in and near the Changbaishan Biosphere Reserve, with samples encompassing old-growth, disturbed forest, and plantations. To approximate conditions for planted trees, sampling focused on trees with exposed crowns (dominant and co-dominant individuals). A log-linear relationship was found between diameter increment and tree diameter, with a linear decrease in increment with increasing local basal area; no significant differences in these patterns between plantations and natural stands were detected for two commonly planted species (Pinus koraiensis and Larix olgensis). A growth model that incorporates observed feedbacks with individual tree size and local basal area (in conjunction with allometric models for tree biomass), was used to project stand-level biomass increment. Predicted growth trajectories were then linked to the carbon process model InTEC to provide estimates of carbon sequestration potential. Results indicate substantial differences among species, and suggest that certain native hardwoods (in particular Fraxinus mandshurica and Phellodendron amurense), have high potential for use in carbon forestry applications. Increased use of native hardwoods in carbon forestry in China is likely to have additional benefits in terms of economic diversification and enhanced provision of "ecosystem services", including biodiversity protection. PMID:17188419

  8. Slope variation and population structure of tree species from different ecological groups in South Brazil.

    PubMed

    Bianchini, Edmilson; Garcia, Cristina C; Pimenta, José A; Torezan, José M D

    2010-09-01

    Size structure and spatial arrangement of 13 abundant tree species were determined in a riparian forest fragment in Paraná State, South Brazil (23°16'S and 51°01'W). The studied species were Aspidosperma polyneuron Müll. Arg., Astronium graveolens Jacq. and Gallesia integrifolia (Spreng) Harms (emergent species); Alseis floribunda Schott, Ruprechtia laxiflora Meisn. and Bougainvillea spectabilis Willd. (shade-intolerant canopy species); Machaerium paraguariense Hassl, Myroxylum peruiferum L. and Chrysophyllum gonocarpum (Mart. & Eichler ex Miq.) Engl. (shade-tolerant canopy species); Sorocea bonplandii (Baill.) Bürger, Trichilia casaretti C. Dc, Trichilia catigua A. Juss. and Actinostemon concolor (Spreng.) Müll. Arg. (understory small trees species). Height and diameter structures and basal area of species were analyzed. Spatial patterns and slope correlation were analyzed by Moran's / spatial autocorrelation coefficient and partial Mantel test, respectively. The emergent and small understory species showed the highest and the lowest variations in height, diameter and basal area. Size distribution differed among emergent species and also among canopy shade-intolerant species. The spatial pattern ranged among species in all groups, except in understory small tree species. The slope was correlated with spatial pattern for A. polyneuron, A. graveolens, A. floribunda, R. laxiflora, M. peruiferum and T. casaretti. The results indicated that most species occurred in specific places, suggesting that niche differentiation can be an important factor in structuring the tree community. PMID:21562693

  9. Method for estimating potential tree-grade distributions for northeastern forest species. Forest Service research paper (Final)

    SciTech Connect

    Yaussy, D.A.

    1993-03-01

    The generalized logistic regression was used to distribute trees into four potential tree grades for 20 northeastern species groups. The potential tree grade is defined as the tree grade based on the length and amount of clear cuttings and defects only, disregarding minimum grading diameter. The algorithms described use site index and tree diameter as the predictive variables, allowing the equations to be incorporated into individual-tree growth and yield simulators such as NE-TWIGS.

  10. Alien Abductions

    NASA Astrophysics Data System (ADS)

    Nickell, Joe

    2000-03-01

    Since the beginning of the modern UFO craze in 1947, an elaborate mythology has developed concerning alleged extraterrestrial visitations. ``Flying saucer" sightings (typically involving misperceptions of such mundane phenomena as meteors and research balloons) began to be accompanied in the 1950s by reports from ``contactees," persons who claimed to have had close encounters with, even to have been transported to distant planets by, UFO occupants. By the 1960s came reports of sporadic ``abductions" which have proliferated in correlation with media interest. (Indeed, by interaction between claimants and media the portrayal of aliens has evolved from a multiplicity of types into the rather standardized big-eyed humanoid model.) While evidence of alien contact has often been faked--as by spurious photos, ``crop circles," and the notorious ``Alien Autopsy" film--few alien abduction reports appear to be hoaxes. Most seem instead to come from sincere, sane individuals. Nevertheless, not one has been authenticated, and serious investigation shows that such claims can be explained as sleep-related phenomena (notably ``waking dreams"), hypnotic confabulation, and other psychological factors. As is typical of other mythologies, the alien myth involves supernormal beings that may interact with humans, and it purports to explain the workings of the universe and humanity's place within it.

  11. Pythium species Associated with Forest Tree Nurseries of Oregon and Washington

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pythium species are one of several pathogen genera responsible for damping off of conifer seedlings in forest tree nurseries. Species identification has been traditionally based on morphology. However, DNA-based identification methods may allow more accurate identification of species associated wi...

  12. Herbs versus Trees: Influences on Teenagers' Knowledge of Plant Species

    ERIC Educational Resources Information Center

    Lückmann, Katrin; Menzel, Susanne

    2014-01-01

    The study reports on species knowledge among German adolescents (n = 507) as: (1) self-assessed evaluation of one's species knowledge; and (2) factual knowledge about popular local herbs and trees. Besides assessing species knowledge, we were interested in whether selected demographic factors, environmental attitude (as measured through the…

  13. Supercooling Capacity Increases from Sea Level to Tree Line in the Hawaiian Tree Species Metrosideros polymorpha.

    PubMed

    Melcher; Cordell; Jones; Scowcroft; Niemczura; Giambelluca; Goldstein

    2000-05-01

    Population-specific differences in the freezing resistance of Metrosideros polymorpha leaves were studied along an elevational gradient from sea level to tree line (located at ca. 2500 m above sea level) on the east flank of the Mauna Loa volcano in Hawaii. In addition, we also studied 8-yr-old saplings grown in a common garden from seeds collected from the same field populations. Leaves of low-elevation field plants exhibited damage at -2 degrees C, before the onset of ice formation, which occurred at -5.7 degrees C. Leaves of high-elevation plants exhibited damage at ca. -8.5 degrees C, concurrent with ice formation in the leaf tissue, which is typical of plants that avoid freezing in their natural environment by supercooling. Nuclear magnetic resonance studies revealed that water molecules of both extra- and intracellular leaf water fractions from high-elevation plants had restricted mobility, which is consistent with their low water content and their high levels of osmotically active solutes. Decreased mobility of water molecules may delay ice nucleation and/or ice growth and may therefore enhance the ability of plant tissues to supercool. Leaf traits that correlated with specific differences in supercooling capacity were in part genetically determined and in part environmentally induced. Evidence indicated that lower apoplastic water content and smaller intercellular spaces were associated with the larger supercooling capacity of the plant's foliage at tree line. The irreversible tissue-damage temperature decreased by ca. 7 degrees C from sea level to tree line in leaves of field populations. However, this decrease appears to be only large enough to allow M. polymorpha trees to avoid leaf tissue damage from freezing up to a level of ca. 2500 m elevation, which is also the current tree line location on the east flank of Mauna Loa. The limited freezing resistance of M. polymorpha leaves may be partially responsible for the occurrence of tree line at a relatively

  14. Predicting spatial variations of tree species richness in tropical forests from high-resolution remote sensing.

    PubMed

    Fricker, Geoffrey A; Wolf, Jeffrey A; Saatchi, Sassan S; Gillespie, Thomas W

    2015-10-01

    There is an increasing interest in identifying theories, empirical data sets, and remote-sensing metrics that can quantify tropical forest alpha diversity at a landscape scale. Quantifying patterns of tree species richness in the field is time consuming, especially in regions with over 100 tree species/ha. We examine species richness in a 50-ha plot in Barro Colorado Island in Panama and test if biophysical measurements of canopy reflectance from high-resolution satellite imagery and detailed vertical forest structure and topography from light detection and ranging (lidar) are associated with species richness across four tree size classes (>1, 1-10, >10, and >20 cm dbh) and three spatial scales (1, 0.25, and 0.04 ha). We use the 2010 tree inventory, including 204,757 individuals belonging to 301 species of freestanding woody plants or 166 ± 1.5 species/ha (mean ± SE), to compare with remote-sensing data. All remote-sensing metrics became less correlated with species richness as spatial resolution decreased from 1.0 ha to 0.04 ha and tree size increased from 1 cm to 20 cm dbh. When all stems with dbh > 1 cm in 1-ha plots were compared to remote-sensing metrics, standard deviation in canopy reflectance explained 13% of the variance in species richness. The standard deviations of canopy height and the topographic wetness index (TWI) derived from lidar were the best metrics to explain the spatial variance in species richness (15% and 24%, respectively). Using multiple regression models, we made predictions of species richness across Barro Colorado Island (BCI) at the 1-ha spatial scale for different tree size classes. We predicted variation in tree species richness among all plants (adjusted r² = 0.35) and trees with dbh > 10 cm (adjusted r² = 0.25). However, the best model results were for understory trees and shrubs (dbh 1-10 cm) (adjusted r² = 0.52) that comprise the majority of species richness in tropical forests. Our results indicate that high

  15. Mountain landscapes offer few opportunities for high-elevation tree species migration

    USGS Publications Warehouse

    Bell, David M.; Bradford, John B.; Lauenroth, William K.

    2014-01-01

    Climate change is anticipated to alter plant species distributions. Regional context, notably the spatial complexity of climatic gradients, may influence species migration potential. While high-elevation species may benefit from steep climate gradients in mountain regions, their persistence may be threatened by limited suitable habitat as land area decreases with elevation. To untangle these apparently contradictory predictions for mountainous regions, we evaluated the climatic suitability of four coniferous forest tree species of the western United States based on species distribution modeling (SDM) and examined changes in climatically suitable areas under predicted climate change. We used forest structural information relating to tree species dominance, productivity, and demography from an extensive forest inventory system to assess the strength of inferences made with a SDM approach. We found that tree species dominance, productivity, and recruitment were highest where climatic suitability (i.e., probability of species occurrence under certain climate conditions) was high, supporting the use of predicted climatic suitability in examining species risk to climate change. By predicting changes in climatic suitability over the next century, we found that climatic suitability will likely decline, both in areas currently occupied by each tree species and in nearby unoccupied areas to which species might migrate in the future. These trends were most dramatic for high elevation species. Climatic changes predicted over the next century will dramatically reduce climatically suitable areas for high-elevation tree species while a lower elevation species, Pinus ponderosa, will be well positioned to shift upslope across the region. Reductions in suitable area for high-elevation species imply that even unlimited migration would be insufficient to offset predicted habitat loss, underscoring the vulnerability of these high-elevation species to climatic changes.

  16. Mountain landscapes offer few opportunities for high-elevation tree species migration.

    PubMed

    Bell, David M; Bradford, John B; Lauenroth, William K

    2014-05-01

    Climate change is anticipated to alter plant species distributions. Regional context, notably the spatial complexity of climatic gradients, may influence species migration potential. While high-elevation species may benefit from steep climate gradients in mountain regions, their persistence may be threatened by limited suitable habitat as land area decreases with elevation. To untangle these apparently contradictory predictions for mountainous regions, we evaluated the climatic suitability of four coniferous forest tree species of the western United States based on species distribution modeling (SDM) and examined changes in climatically suitable areas under predicted climate change. We used forest structural information relating to tree species dominance, productivity, and demography from an extensive forest inventory system to assess the strength of inferences made with a SDM approach. We found that tree species dominance, productivity, and recruitment were highest where climatic suitability (i.e., probability of species occurrence under certain climate conditions) was high, supporting the use of predicted climatic suitability in examining species risk to climate change. By predicting changes in climatic suitability over the next century, we found that climatic suitability will likely decline, both in areas currently occupied by each tree species and in nearby unoccupied areas to which species might migrate in the future. These trends were most dramatic for high elevation species. Climatic changes predicted over the next century will dramatically reduce climatically suitable areas for high-elevation tree species while a lower elevation species, Pinus ponderosa, will be well positioned to shift upslope across the region. Reductions in suitable area for high-elevation species imply that even unlimited migration would be insufficient to offset predicted habitat loss, underscoring the vulnerability of these high-elevation species to climatic changes. PMID:24353188

  17. Anonymous nuclear markers data supporting species tree phylogeny and divergence time estimates in a cactus species complex in South America.

    PubMed

    Perez, Manolo F; Carstens, Bryan C; Rodrigues, Gustavo L; Moraes, Evandro M

    2016-03-01

    Supportive data related to the article "Anonymous nuclear markers reveal taxonomic incongruence and long-term disjunction in a cactus species complex with continental-island distribution in South America" (Perez et al., 2016) [1]. Here, we present pyrosequencing results, primer sequences, a cpDNA phylogeny, and a species tree phylogeny. PMID:26900589

  18. Version 5 of Forecasts; Forecasts of Climate-Associated Shifts in Tree Species

    NASA Astrophysics Data System (ADS)

    Hargrove, W. W.; Kumar, J.; Potter, K. M.; Hoffman, F. M.

    2014-12-01

    Version 5 of the ForeCASTS tree range shift atlas (www.geobabble.org/~hnw/global/treeranges5/climate_change/atlas.html) now predicts global shifts in the suitable ranges of 335 tree species (essentially all woody species measured in Forest Inventory Analysis (FIA)) under forecasts from the Parallel Climate Model, and the Hadley Model, each under future climatic scenarios A1 and B1, each at two future dates (2050 and 2100). Version 5 includes more Global Biodiversity Information Facility (GBIF) occurrence points, uses improved heuristics for occurrence training, and recovers occurrence points that fall in water. A multivariate clustering procedure was used to quantitatively delineate 30 thousand environmentally homogeneous ecoregions across present and 8 potential future global locations at once, using global maps of 17 environmental characteristics describing temperature, precipitation, soils, topography and solar insolation. Occurrence of each tree species on FIA plots and in GBIF samples was used to identify a subset of suitable ecoregions from the full set of 30 thousand. This subset of suitable ecoregions was compared to the known current present range of the tree species. Predicted present ranges correspond well with existing ranges for all but a few of the 335 tree species. The subset of suitable ecoregions can then be tracked into the future to determine whether the suitable home range remains the same, moves, grows, shrinks, or disappears under each model/scenario combination. A quantitative niche breadth analysis allows sorting of the 17 environmental variables from the narrowest, most important, to the broadest, least restrictive environmental factors limiting each tree species. Potential tree richness maps were produced, along with a quantitative potential tree endemism map for present and future CONUS. Using a new empirical imputation method which associates sparse measurements of dependent variables with particular clustered combinations of the

  19. Extending the dormant bud cryopreservation method to new tree species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In cryopreservation of germplasm, using dormant winter buds (DB) as source plant material is economically favorable over tissue culture options. Although the DB cryopreservation method has been known for many years, the approach is feasible only for cryopreserving a select number of temperate tree s...

  20. North American tree squirrels and ground squirrels with overlapping ranges host different Cryptosporidium species and genotypes.

    PubMed

    Stenger, Brianna L S; Clark, Mark E; Kváč, Martin; Khan, Eakalak; Giddings, Catherine W; Prediger, Jitka; McEvoy, John M

    2015-12-01

    Wildlife-associated Cryptosporidium are an emerging cause of cryptosporidiosis in humans. The present study was undertaken to determine the extent to which North American tree squirrels and ground squirrels host zoonotic Cryptosporidium species and genotypes. Fragments of the Cryptosporidium 18S rRNA and actin genes were amplified and sequenced from fecal samples obtained from three tree squirrel and three ground squirrel species. In tree squirrels, Cryptosporidium was identified in 40.5% (17/42) of American red squirrels (Tamiasciurus hudsonicus), 40.4% (55/136) of eastern gray squirrels (Sciurus carolinensis), and 28.6% (2/7) of fox squirrels (Sciurus niger). Human-pathogenic Cryptosporidium ubiquitum and Cryptosporidium skunk genotype were the most prevalent species/genotypes in tree squirrels. Because tree squirrels live in close proximity to humans and are frequently infected with potentially zoonotic Cryptosporidium species/genotypes, they may be a significant reservoir of infection in humans. In ground squirrels, Cryptosporidium was detected in 70.2% (33/47) of 13-lined ground squirrels (Ictidomys tridecemlineatus), 35.1% (27/77) of black-tailed prairie dogs (Cynomys ludovicianus), and the only golden-mantled ground squirrel (Callospermophilus lateralis) that was sampled. Cryptosporidium rubeyi and ground squirrel genotypes I, II, and III were identified in isolates from these ground squirrel species. In contrast to the Cryptosporidium infecting tree squirrels, these species/genotypes appear to be specific for ground squirrels and are not associated with human disease. PMID:26437239

  1. Long range correlations in tree ring chronologies of the USA: Variation within and across species

    NASA Astrophysics Data System (ADS)

    Bowers, M. C.; Gao, J. B.; Tung, W. W.

    2013-02-01

    Abstract <span class="hlt">Tree</span> ring width data are among the best proxies for reconstructing past temperature and precipitation records. The discovery of fractal scaling and long-memory in meteorological and hydrological signals motivates us to investigate such properties in <span class="hlt">tree</span> ring chronologies. Detrended fluctuation analysis and adaptive fractal analysis are utilized to estimate the Hurst parameter values of 697 <span class="hlt">tree</span> ring chronologies from the continental United States. We find significant differences in the Hurst parameter values across the 10 <span class="hlt">species</span> studied in the work. The long-range scaling relations found here suggest that the behavior of <span class="hlt">tree</span> ring growth observed in a short calibration period may be similar to the general behavior of <span class="hlt">tree</span> ring growth in a much longer period, and therefore, the limited calibration period may be more useful than originally thought. The variations of the long-range correlations within and across <span class="hlt">species</span> may be further explored in future to better reconstruct paleoclimatic records.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3178650','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3178650"><span id="translatedtitle">Growth Strategies of Tropical <span class="hlt">Tree</span> <span class="hlt">Species</span>: Disentangling Light and Size Effects</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Rüger, Nadja; Berger, Uta; Hubbell, Stephen P.; Vieilledent, Ghislain; Condit, Richard</p> <p>2011-01-01</p> <p>An understanding of the drivers of <span class="hlt">tree</span> growth at the <span class="hlt">species</span> level is required to predict likely changes of carbon stocks and biodiversity when environmental conditions change. Especially in <span class="hlt">species</span>-rich tropical forests, it is largely unknown how <span class="hlt">species</span> differ in their response of growth to resource availability and individual size. We use a hierarchical Bayesian approach to quantify the impact of light availability and <span class="hlt">tree</span> diameter on growth of 274 woody <span class="hlt">species</span> in a 50-ha long-term forest census plot in Barro Colorado Island, Panama. Light reaching each individual <span class="hlt">tree</span> was estimated from yearly vertical censuses of canopy density. The hierarchical Bayesian approach allowed accounting for different sources of error, such as negative growth observations, and including rare <span class="hlt">species</span> correctly weighted by their abundance. All <span class="hlt">species</span> grew faster at higher light. Exponents of a power function relating growth to light were mostly between 0 and 1. This indicates that nearly all <span class="hlt">species</span> exhibit a decelerating increase of growth with light. In contrast, estimated growth rates at standardized conditions (5 cm dbh, 5% light) varied over a 9-fold range and reflect strong growth-strategy differentiation between the <span class="hlt">species</span>. As a consequence, growth rankings of the <span class="hlt">species</span> at low (2%) and high light (20%) were highly correlated. Rare <span class="hlt">species</span> tended to grow faster and showed a greater sensitivity to light than abundant <span class="hlt">species</span>. Overall, <span class="hlt">tree</span> size was less important for growth than light and about half the <span class="hlt">species</span> were predicted to grow faster in diameter when bigger or smaller, respectively. Together light availability and <span class="hlt">tree</span> diameter only explained on average 12% of the variation in growth rates. Thus, other factors such as soil characteristics, herbivory, or pathogens may contribute considerably to shaping <span class="hlt">tree</span> growth in the tropics. PMID:21966498</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JHyd..537....1S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JHyd..537....1S&link_type=ABSTRACT"><span id="translatedtitle">Inter- and intra-specific variation in stemflow for evergreen <span class="hlt">species</span> and deciduous <span class="hlt">tree</span> <span class="hlt">species</span> in a subtropical forest</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Su, Lei; Xu, Wenting; Zhao, Changming; Xie, Zongqiang; Ju, Hua</p> <p>2016-06-01</p> <p>Quantification of stemflow is necessary for the assessment of forest ecosystem hydrological effects. Nevertheless, variation of stemflow among plant functional groups is currently not well understood. Stemflow production of co-occurring evergreen broadleaved <span class="hlt">trees</span> (Cyclobalanopsis multinervis and Cyclobalanopsis oxyodon) and deciduous broadleaved <span class="hlt">trees</span> (Fagus engleriana and Quercus serrata var. brevipetiolata) was quantified through field observations in a mixed evergreen and deciduous broadleaved forest. The research results revealed that stemflow increased linearly with increasing rainfall magnitude, with precipitation depths of 6.9, 7.2, 10.0 and 14.8 mm required for the initiation of stemflow for C. multinervis, C. oxyodon, F. engleriana and Q. serrata, respectively. Stemflow percentage and funneling ratio (FR) increased with increasing rainfall in a logarithmic fashion. Stemflow percentage and FR tended to grow rapidly with increasing rainfall magnitude up to a rainfall threshold of 50 mm, above which, further rainfall increases brought about only small increases. For C. multinervis, C. oxyodon, F. engleriana and Q. serrata, FR averaged 19.8, 14.8, 8.9 and 2.8, respectively. The stemflow generating rainfall thresholds for evergreen <span class="hlt">species</span> were smaller than for deciduous <span class="hlt">species</span>. Furthermore, stemflow percentage and FR of the former was greater than the latter. For both evergreen <span class="hlt">species</span> and deciduous <span class="hlt">species</span>, overall funneling ratio (FRs) decreased with increasing basal area. We concluded that: (1) although stemflow partitioning represented a fairly low percentage of gross rainfall in mixed evergreen and deciduous broadleaved forests, it was capable of providing substantial amount of rainwater to <span class="hlt">tree</span> boles; (2) the evergreen <span class="hlt">species</span> were more likely to generate stemflow than deciduous <span class="hlt">species</span>, and directed more intercepted rainwater to the root zone; (3) small <span class="hlt">trees</span> were more productive in funneling stemflow than larger <span class="hlt">trees</span>, which may provide a favorable</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2694365','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2694365"><span id="translatedtitle"><span class="hlt">Tree</span> <span class="hlt">Species</span> Traits Influence Soil Physical, Chemical, and Biological Properties in High Elevation Forests</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ayres, Edward; Steltzer, Heidi; Berg, Sarah; Wallenstein, Matthew D.; Simmons, Breana L.; Wall, Diana H.</p> <p>2009-01-01</p> <p>Background Previous studies have shown that plants often have <span class="hlt">species</span>-specific effects on soil properties. In high elevation forests in the Southern Rocky Mountains, North America, areas that are dominated by a single <span class="hlt">tree</span> <span class="hlt">species</span> are often adjacent to areas dominated by another <span class="hlt">tree</span> <span class="hlt">species</span>. Here, we assessed soil properties beneath adjacent stands of trembling aspen, lodgepole pine, and Engelmann spruce, which are dominant <span class="hlt">tree</span> <span class="hlt">species</span> in this region and are distributed widely in North America. We hypothesized that soil properties would differ among stands dominated by different <span class="hlt">tree</span> <span class="hlt">species</span> and expected that aspen stands would have higher soil temperatures due to their open structure, which, combined with higher quality litter, would result in increased soil respiration rates, nitrogen availability, and microbial biomass, and differences in soil faunal community composition. Methodology/Principal Findings We assessed soil physical, chemical, and biological properties at four sites where stands of aspen, pine, and spruce occurred in close proximity to one-another in the San Juan Mountains, Colorado. Leaf litter quality differed among the <span class="hlt">tree</span> <span class="hlt">species</span>, with the highest nitrogen (N) concentration and lowest lignin∶N in aspen litter. Nitrogen concentration was similar in pine and spruce litter, but lignin∶N was highest in pine litter. Soil temperature and moisture were highest in aspen stands, which, in combination with higher litter quality, probably contributed to faster soil respiration rates from stands of aspen. Soil carbon and N content, ammonium concentration, and microbial biomass did not differ among <span class="hlt">tree</span> <span class="hlt">species</span>, but nitrate concentration was highest in aspen soil and lowest in spruce soil. In addition, soil fungal, bacterial, and nematode community composition and rotifer, collembolan, and mesostigmatid mite abundance differed among the <span class="hlt">tree</span> <span class="hlt">species</span>, while the total abundance of nematodes, tardigrades, oribatid mites, and prostigmatid mites did not</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=64306&keyword=Taxonomy&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=65294418&CFTOKEN=71908534','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=64306&keyword=Taxonomy&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=65294418&CFTOKEN=71908534"><span id="translatedtitle">ISOPRENE EMISSION CAPACITY FOR U.S. <span class="hlt">TREE</span> <span class="hlt">SPECIES</span></span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>Isoprene emission capacity measurements are presented from 18 North American oak <I>(Quercus)</I> <span class="hlt">species</span> and <span class="hlt">species</span> from six other genera previously found to emit significant quantities of isoprene. Sampling was conducted at physiographically diverse locations in North Carolina...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24233419','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24233419"><span id="translatedtitle">Ozone exposure : Areas of potential ozone risk for selected <span class="hlt">tree</span> <span class="hlt">species</span> in Austria.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Loibl, W; Smidt, S</p> <p>1996-12-01</p> <p>Increased tropospheric ozone concentrations cause damage to both human health and the environment. To assess the exposure of forest areas and selected <span class="hlt">tree</span> <span class="hlt">species</span> to ozone, it is necessary to calculate the ozone exposure distribution. The present article describes the application of an ozone interpolation model to the calculation of the ozone exposure distribution in combination with forest inventory data.The exposure of forest regions to ozone was assessed by means of an AOT40 map (accumulated ozone exposure over a threshold of 40 ppb). The calculation was performed by hourly running of the model during the summer term and accumulation of the patterns that exceeded 40 ppb.The exposure of the primary Austrian <span class="hlt">tree</span> <span class="hlt">species</span> to ozone can be assessed due to the spatial relation of ozone exposure and <span class="hlt">tree</span> <span class="hlt">species</span> patterns. This spatial relation also allows the verification of assumptions concerning ozone-related <span class="hlt">tree</span> damage. PMID:24233419</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015EGUGA..17.8279L&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015EGUGA..17.8279L&link_type=ABSTRACT"><span id="translatedtitle">Temporal and Spatial Dynamics of <span class="hlt">Tree</span> <span class="hlt">Species</span> Composition in Temperate Mountains of South Korea</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, Boknam; Park, Juhan; Cho, Sungsik; Ryu, Daun; Zaw Wynn, Khine; Park, Minji; Cho, Sunhee; Yoon, Jongguk; Park, Jongyoung; Kim, Hyun Seok</p> <p>2015-04-01</p> <p>Long term studies on vegetation dynamics are important to identify changes of ecosystem-level responses to climate change. To learn how <span class="hlt">tree</span> <span class="hlt">species</span> composition and stand structure change across temperate mountains, the temporal and spatial variations in <span class="hlt">tree</span> <span class="hlt">species</span> diversity and structure were investigated using the <span class="hlt">species</span> composition and DBH size collected over the fourteen-year period across 134 sites in Jiri and Baekoon Mountains, South Korea. The overall temporal changes over fourteen years showed significant increase in stand density, <span class="hlt">species</span> diversity and evenness according to the indices of Shannon-Weiner diversity, Bray-Curtis dissimilarity, and Pielou's evenness, contributing to the increase of basal area and biomass growth. The change of <span class="hlt">tree</span> <span class="hlt">species</span> composition could be categorized into five <span class="hlt">species</span> communities, representing gradual increase or decrease, establishment, extinction, fluctuation of <span class="hlt">species</span> population. However, in general, the change in <span class="hlt">species</span> composition appeared to have consistent and directional patterns of increase in the annual rate of change in the mean <span class="hlt">species</span> traits including <span class="hlt">species</span> richness, pole growth rate, adult growth rate, and adult stature with five common dominant <span class="hlt">species</span> (Quercus mongolica, Quercus variabilis, Quercus serrata, Carpinus laxiflora, and Styrax japonicus). The spatial patterns of <span class="hlt">species</span> composition appeared to have a higher stand density and <span class="hlt">species</span> diversity along with the low latitude and high slope ecosystem. The climate change was another main driver to vary the distribution of <span class="hlt">species</span> abundance. Overall, both temporal and spatial changes of composition in <span class="hlt">tree</span> <span class="hlt">species</span> community was clear and further analysis to clarify the reasons for such fast and <span class="hlt">species</span>-specific changes is underway especially to separate the effect of successional change and climate change. Keywords <span class="hlt">species</span> composition; climate change; temporal and spatial variation ; forest structure; temperate forest</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25761711','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25761711"><span id="translatedtitle">Glacial refugia and modern genetic diversity of 22 western North American <span class="hlt">tree</span> <span class="hlt">species</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Roberts, David R; Hamann, Andreas</p> <p>2015-04-01</p> <p>North American <span class="hlt">tree</span> <span class="hlt">species</span>, subspecies and genetic varieties have primarily evolved in a landscape of extensive continental ice and restricted temperate climate environments. Here, we reconstruct the refugial history of western North American <span class="hlt">trees</span> since the last glacial maximum using <span class="hlt">species</span> distribution models, validated against 3571 palaeoecological records. We investigate how modern subspecies structure and genetic diversity corresponds to modelled glacial refugia, based on a meta-analysis of allelic richness and expected heterozygosity for 473 populations of 22 <span class="hlt">tree</span> <span class="hlt">species</span>. We find that <span class="hlt">species</span> with strong genetic differentiation into subspecies had widespread and large glacial refugia, whereas <span class="hlt">species</span> with restricted refugia show no differentiation among populations and little genetic diversity, despite being common over a wide range of environments today. In addition, a strong relationship between allelic richness and the size of modelled glacial refugia (r(2) = 0.55) suggest that population bottlenecks during glacial periods had a pronounced effect on the presence of rare alleles. PMID:25761711</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4375868','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4375868"><span id="translatedtitle">Glacial refugia and modern genetic diversity of 22 western North American <span class="hlt">tree</span> <span class="hlt">species</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Roberts, David R.; Hamann, Andreas</p> <p>2015-01-01</p> <p>North American <span class="hlt">tree</span> <span class="hlt">species</span>, subspecies and genetic varieties have primarily evolved in a landscape of extensive continental ice and restricted temperate climate environments. Here, we reconstruct the refugial history of western North American <span class="hlt">trees</span> since the last glacial maximum using <span class="hlt">species</span> distribution models, validated against 3571 palaeoecological records. We investigate how modern subspecies structure and genetic diversity corresponds to modelled glacial refugia, based on a meta-analysis of allelic richness and expected heterozygosity for 473 populations of 22 <span class="hlt">tree</span> <span class="hlt">species</span>. We find that <span class="hlt">species</span> with strong genetic differentiation into subspecies had widespread and large glacial refugia, whereas <span class="hlt">species</span> with restricted refugia show no differentiation among populations and little genetic diversity, despite being common over a wide range of environments today. In addition, a strong relationship between allelic richness and the size of modelled glacial refugia (r2 = 0.55) suggest that population bottlenecks during glacial periods had a pronounced effect on the presence of rare alleles. PMID:25761711</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/1015692','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/1015692"><span id="translatedtitle">Relationships among environmental variables and distribution of <span class="hlt">tree</span> <span class="hlt">species</span> at high elevation in the Olympic Mountains</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Woodward, Andrea</p> <p>1998-01-01</p> <p>Relationships among environmental variables and occurrence of <span class="hlt">tree</span> <span class="hlt">species</span> were investigated at Hurricane Ridge in Olympic National Park, Washington, USA. A transect consisting of three plots was established down one north-and one south-facing slope in stands representing the typical elevational sequence of <span class="hlt">tree</span> <span class="hlt">species</span>. <span class="hlt">Tree</span> <span class="hlt">species</span> included subalpine fir (Abies lasiocarpa), Douglas-fir (Pseudotsuga menziesii), mountain hemlock (Tsuga mertensiana), and Pacific silver fir (Abies amabilis). Air and soil temperature, precipitation, and soil moisture were measured during three growing seasons. Snowmelt patterns, soil carbon and moisture release curves were also determined. The plots represented a wide range in soil water potential, a major determinant of <span class="hlt">tree</span> <span class="hlt">species</span> distribution (range of minimum values = -1.1 to -8.0 MPa for Pacific silver fir and Douglas-fir plots, respectively). Precipitation intercepted at plots depended on topographic location, storm direction and storm type. Differences in soil moisture among plots was related to soil properties, while annual differences at each plot were most often related to early season precipitation. Changes in climate due to a doubling of atmospheric CO2 will likely shift <span class="hlt">tree</span> <span class="hlt">species</span> distributions within, but not among aspects. Change will be buffered by innate tolerance of adult <span class="hlt">trees</span> and the inertia of soil properties.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25712048','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25712048"><span id="translatedtitle">Regional-scale directional changes in abundance of <span class="hlt">tree</span> <span class="hlt">species</span> along a temperature gradient in Japan.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Suzuki, Satoshi N; Ishihara, Masae I; Hidaka, Amane</p> <p>2015-09-01</p> <p>Climate changes are assumed to shift the ranges of <span class="hlt">tree</span> <span class="hlt">species</span> and forest biomes. Such range shifts result from changes in abundances of <span class="hlt">tree</span> <span class="hlt">species</span> or functional types. Owing to global warming, the abundance of a <span class="hlt">tree</span> <span class="hlt">species</span> or functional type is expected to increase near the colder edge of its range and decrease near the warmer edge. This study examined directional changes in abundance and demographic parameters of forest <span class="hlt">trees</span> along a temperature gradient, as well as a successional gradient, in Japan. Changes in the relative abundance of each of four functional types (evergreen broad-leaved, deciduous broad-leaved, evergreen temperate conifer, and evergreen boreal conifer) and the demography of each <span class="hlt">species</span> (recruitment rate, mortality, and population growth rate) were analyzed in 39 permanent forest plots across the Japanese archipelago. Directional changes in the relative abundance of functional types were detected along the temperature gradient. Relative abundance of evergreen broad-leaved <span class="hlt">trees</span> increased near their colder range boundaries, especially in secondary forests, coinciding with the decrease in deciduous broad-leaved <span class="hlt">trees</span>. Similarly, relative abundance of deciduous broad-leaved <span class="hlt">trees</span> increased near their colder range boundaries, coinciding with the decrease in boreal conifers. These functional-type-level changes were mainly due to higher recruitment rates and partly to the lower mortality of individual <span class="hlt">species</span> at colder sites. This is the first report to show that <span class="hlt">tree</span> <span class="hlt">species</span> abundances in temperate forests are changing directionally along a temperature gradient, which might be due to current or past climate changes as well as recovery from past disturbances. PMID:25712048</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/12620063','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/12620063"><span id="translatedtitle">Identification, measurement and interpretation of <span class="hlt">tree</span> rings in woody <span class="hlt">species</span> from mediterranean climates.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cherubini, Paolo; Gartner, Barbara L; Tognetti, Roberto; Bräker, Otto U; Schoch, Werner; Innes, John L</p> <p>2003-02-01</p> <p>We review the literature dealing with mediterranean climate, vegetation, phenology and ecophysiology relevant to the understanding of <span class="hlt">tree</span>-ring formation in mediterranean regions. <span class="hlt">Tree</span> rings have been used extensively in temperate regions to reconstruct responses of forests to past environmental changes. In mediterranean regions, studies of <span class="hlt">tree</span> rings are scarce, despite their potential for understanding and predicting the effects of global change on important ecological processes such as desertification. In mediterranean regions, due to the great spatio-temporal variability of mediterranean environmental conditions, <span class="hlt">tree</span> rings are sometimes not formed. Often, clear seasonality is lacking, and vegetation activity is not always associated with regular dormancy periods. We present examples of <span class="hlt">tree</span>-ring morphology of five <span class="hlt">species</span> (Arbutus unedo, Fraxinus ornus, Quercus cerris, Q. ilex, Q. pubescens) sampled in Tuscany, Italy, focusing on the difficulties we encountered during the dating. We present an interpretation of anomalies found in the wood structure and, more generally, of cambial activity in such environments. Furthermore, we propose a classification of <span class="hlt">tree</span>-ring formation in mediterranean environments. Mediterranean <span class="hlt">tree</span> rings can be dated and used for dendrochronological purposes, but great care should be taken in selecting sampling sites, <span class="hlt">species</span> and sample <span class="hlt">trees</span>. PMID:12620063</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015EGUGA..1712601J&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015EGUGA..1712601J&link_type=ABSTRACT"><span id="translatedtitle">Does deciduous <span class="hlt">tree</span> <span class="hlt">species</span> identity affect carbon storage in temperate soils?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jungkunst, Hermann; Schleuß, Per; Heitkamp, Felix</p> <p>2015-04-01</p> <p>Forest soils contribute roughly 70 % to the global terrestrial soil organic carbon (SOC) pool and thus play a vital role in the global carbon cycle. It is less clear, however, whether temperate <span class="hlt">tree</span> <span class="hlt">species</span> identity affects SOC storage beyond the coarse differentiation between coniferous and deciduous <span class="hlt">trees</span>. The most important driver for soil SOC storage definitely is the fine mineral fraction (clay and fine silt) because of its high sorption ability. It is difficult to disentangle any additional biotic effects since clay and silt vary considerably in nature. For experimental approaches, the process of soil carbon accumulation is too slow and, therefore, sound results cannot be expected for decades. Here we will present our success to distinguish between the effects of fine particle content (abiotic) and <span class="hlt">tree</span> <span class="hlt">species</span> composition (biotic) on the SOC pool in an old-growth broad-leaved forest plots along a <span class="hlt">tree</span> diversity gradient , i.e., 1- (beech), 3- (plus ash and lime <span class="hlt">tree</span>)- and 5-(plus maple and hornbeam) <span class="hlt">species</span>. The particle size fractions were separated first and then the carbon concentrations of each fraction was measured. Hence, the carbon content per unit clay was not calculated, as usually done, but directly measured. As expected, the variation in SOC content was mainly explained by the variations in clay content but not entirely. We found that the carbon concentration per unit clay and fine silt in the subsoil was by 30-35% higher in mixed than in monospecific stands indicating a significant <span class="hlt">species</span> identity or <span class="hlt">species</span> diversity effect on C stabilization. In contrast to the subsoil, no <span class="hlt">tree</span> <span class="hlt">species</span> effects was identified for the topsoil. Indications are given that the mineral phase was already carbon saturated and thus left no more room for a possible biotic effect. Underlying processes must remain speculative, but we will additionally present our latest microcosm results, including isotopic signatures, to underpin the proposed deciduous <span class="hlt">tree</span> <span class="hlt">species</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/17665219','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/17665219"><span id="translatedtitle">Population structure, physiology and ecohydrological impacts of dioecious riparian <span class="hlt">tree</span> <span class="hlt">species</span> of western North America.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hultine, K R; Bush, S E; West, A G; Ehleringer, J R</p> <p>2007-11-01</p> <p>The global water cycle is intimately linked to vegetation structure and function. Nowhere is this more apparent than in the arid west where riparian forests serve as ribbons of productivity in otherwise mostly unproductive landscapes. Dioecy is common among <span class="hlt">tree</span> <span class="hlt">species</span> that make up western North American riparian forests. There are intrinsic physiological differences between male and female dioecious riparian <span class="hlt">trees</span> that may influence population structure (i.e., the ratio of male to female <span class="hlt">trees</span>) and impact ecohydrology at large scales. In this paper, we review the current literature on sex ratio patterns and physiology of dioecious riparian <span class="hlt">tree</span> <span class="hlt">species</span>. Then develop a conceptual framework of the mechanisms that underlie population structure of dominant riparian <span class="hlt">tree</span> <span class="hlt">species</span>. Finally, we identify linkages between population structure and ecohydrological processes such as evapotranspiration and streamflow. A more thorough understanding of the mechanisms that underlie population structure of dominant riparian <span class="hlt">tree</span> <span class="hlt">species</span> will enable us to better predict global change impacts on vegetation and water cycling at multiple scales. PMID:17665219</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/861330','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/861330"><span id="translatedtitle">Ambrosia Beetle (Coleoptera: Scolytidae) <span class="hlt">Species</span>, Flight, and Attack on Living Eastern Cottonwood <span class="hlt">Trees</span>.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Coyle, D R; D.C. Booth: M.S. Wallace</p> <p>2005-12-01</p> <p>ABSTRACT In spring 2002, ambrosia beetles (Coleoptera: Scolytidae) infested an intensively managed 22-ha <span class="hlt">tree</span> plantation on the upper coastal plain of South Carolina. Nearly 3,500 scolytids representing 28 <span class="hlt">species</span> were captured in ethanol-baited traps from 18 June 2002 to 18 April 2004. More than 88% of total captures were exotic <span class="hlt">species</span>. Five <span class="hlt">species</span> [Dryoxylon onoharaensum (Murayama), Euwallacea validus (Eichhoff), Pseudopityophthorus minutissimus (Zimmermann), Xyleborus atratus Eichhoff, and Xyleborus impressus Eichhoff]) were collected in South Carolina for the first time. Of four <span class="hlt">tree</span> <span class="hlt">species</span> in the plantation, eastern cottonwood, Populus deltoides Bartram, was the only one attacked, with nearly 40% of the <span class="hlt">trees</span> sustaining ambrosia beetle damage. Clone ST66 sustained more damage than clone S7C15. ST66 <span class="hlt">trees</span> receiving fertilization were attacked more frequently than <span class="hlt">trees</span> receiving irrigation, irrigation_fertilization, or controls, although the number of S7C15 <span class="hlt">trees</span> attacked did not differ among treatments. The study location is near major shipping ports; our results demonstrate the necessity for intensive monitoring programs to determine the arrival, spread, ecology, and impact of exotic scolytids.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010004212','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010004212"><span id="translatedtitle">BOREAS TE-4 Branch Bag Data From Boreal <span class="hlt">Tree</span> <span class="hlt">Species</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hall, Forrest G. (Editor); Papagno, Andrea (Editor); Berry, Joseph A.; Fu, Wei; Fredeen, Art; Gamon, John</p> <p>2000-01-01</p> <p>The BOREAS TE-4 team collected continuous records of gas exchange under ambient conditions from intact boreal forest <span class="hlt">trees</span> in the BOREAS NSA from 23-Jul-1996 until 14-Aug-1996. These measurements can be used to test models of photosynthesis, stomatal conductance, and leaf respiration, such as SiB2 (Sellers et al., 1996) or the leaf model (Collatz et al., 1991), and programs can be obtained from the investigators. The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.B13B0476R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.B13B0476R"><span id="translatedtitle">Wind Disturbance Produced Changes in <span class="hlt">Tree</span> <span class="hlt">Species</span> Assemblage in the Peruvian Amazon</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rifai, S. W.; Chambers, J. Q.; Negron Juarez, R. I.; Ramirez, F.; Tello, R.; Alegria Muñoz, W.</p> <p>2010-12-01</p> <p>Wind disturbance has been a frequently overlooked abiotic cause of mass <span class="hlt">tree</span> mortality in the Amazon basin. In the Peruvian Amazon these wind disturbances are produced by meteorological events such as convective systems. Downbursts for example produce short term descendent wind speeds that can be in excess of 30 m s-1. These are capable of producing <span class="hlt">tree</span> blowdowns which have been reported to be as large as 33 km2 in the Amazon basin. We used the chronosequence of Landsat Satellite imagery to find and locate where these blowdowns have occurred in the Loreto region of the Peruvian Amazon. Spectral Mixture Analysis was used to estimate the proportion landcover of green vegetation, non-photosynthetic vegetation (NPV), soil and shade in each pixel. The change in NPV was calculated by subtracting the NPV signal in the Landsat image prior to the blowdown occurrence, from the image following the disturbance. Our prior research has established a linear relationship between <span class="hlt">tree</span> mortality and change in NPV. It is hypothesized that these mass <span class="hlt">tree</span> mortality events result in changes in the <span class="hlt">tree</span> <span class="hlt">species</span> assemblage of affected forests. Here we present preliminary <span class="hlt">tree</span> <span class="hlt">species</span> assemblage data from two sites in the Peruvian Amazon near Iquitos, Peru. The site (ALP) at the Allpahuayo Mishana reserve (3.945 S, 73.455 W) is 30 km south of Iquitos, Peru, and hosts the remnants of a 50 ha blowdown that occurred in either 1992 or 1993. Another site (NAPO) on the Napo river about 60 km north of Iquitos, is the location of an approximately 300 ha blowdown that occurred in 1998. At each site, a 3000 m x 10 m transect encompassing non disturbed and disturbed areas was installed, and <span class="hlt">trees</span> greater than 10 cm diameter at breast height were measured for diameter, height and were identified to the <span class="hlt">species</span>. Stem density of <span class="hlt">trees</span> with diameter at breast height > 10 cm, and <span class="hlt">tree</span> height appear to be similar both inside and outside the blowdown affected areas of the forests at both sites. At the ALP</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=238475','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=238475"><span id="translatedtitle">Impact of Fumigation on Pythium <span class="hlt">Species</span> Associated with Forest <span class="hlt">Tree</span> Nurseries of Oregon and Washington</span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p>Pythium <span class="hlt">species</span> cause damping off of conifer seedlings in forest <span class="hlt">tree</span> nurseries. Identification of the <span class="hlt">species</span> responsible for the disease has been traditionally based on morphology. However, newer DNA-based identification methods may allow more accurate identification and assessment of soil popul...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26936241','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26936241"><span id="translatedtitle">Selective logging in tropical forests decreases the robustness of liana-<span class="hlt">tree</span> interaction networks to the loss of host <span class="hlt">tree</span> <span class="hlt">species</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Magrach, Ainhoa; Senior, Rebecca A; Rogers, Andrew; Nurdin, Deddy; Benedick, Suzan; Laurance, William F; Santamaria, Luis; Edwards, David P</p> <p>2016-03-16</p> <p>Selective logging is one of the major drivers of tropical forest degradation, causing important shifts in <span class="hlt">species</span> composition. Whether such changes modify interactions between <span class="hlt">species</span> and the networks in which they are embedded remain fundamental questions to assess the 'health' and ecosystem functionality of logged forests. We focus on interactions between lianas and their <span class="hlt">tree</span> hosts within primary and selectively logged forests in the biodiversity hotspot of Malaysian Borneo. We found that lianas were more abundant, had higher <span class="hlt">species</span> richness, and different <span class="hlt">species</span> compositions in logged than in primary forests. Logged forests showed heavier liana loads disparately affecting slow-growing <span class="hlt">tree</span> <span class="hlt">species</span>, which could exacerbate the loss of timber value and carbon storage already associated with logging. Moreover, simulation scenarios of host <span class="hlt">tree</span> local <span class="hlt">species</span> loss indicated that logging might decrease the robustness of liana-<span class="hlt">tree</span> interaction networks if heavily infested <span class="hlt">trees</span> (i.e. the most connected ones) were more likely to disappear. This effect is partially mitigated in the short term by the colonization of host <span class="hlt">trees</span> by a greater diversity of liana <span class="hlt">species</span> within logged forests, yet this might not compensate for the loss of preferred <span class="hlt">tree</span> hosts in the long term. As a consequence, <span class="hlt">species</span> interaction networks may show a lagged response to disturbance, which may trigger sudden collapses in <span class="hlt">species</span> richness and ecosystem function in response to additional disturbances, representing a new type of 'extinction debt'. PMID:26936241</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3460976','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3460976"><span id="translatedtitle">Spatial Distribution and Interspecific Associations of <span class="hlt">Tree</span> <span class="hlt">Species</span> in a Tropical Seasonal Rain Forest of China</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lan, Guoyu; Getzin, Stephan; Wiegand, Thorsten; Hu, Yuehua; Xie, Guishui; Zhu, Hua; Cao, Min</p> <p>2012-01-01</p> <p>Studying the spatial pattern and interspecific associations of plant <span class="hlt">species</span> may provide valuable insights into processes and mechanisms that maintain <span class="hlt">species</span> coexistence. Point pattern analysis was used to analyze the spatial distribution patterns of twenty dominant <span class="hlt">tree</span> <span class="hlt">species</span>, their interspecific spatial associations and changes across life stages in a 20-ha permanent plot of seasonal tropical rainforest in Xishuangbanna, China, to test mechanisms maintaining <span class="hlt">species</span> coexistence. Torus-translation tests were used to quantify positive or negative associations of the <span class="hlt">species</span> to topographic habitats. The results showed: (1) fourteen of the twenty <span class="hlt">tree</span> <span class="hlt">species</span> were negatively (or positively) associated with one or two of the topographic variables, which evidences that the niche contributes to the spatial pattern of these <span class="hlt">species</span>. (2) Most saplings of the study <span class="hlt">species</span> showed a significantly clumped distribution at small scales (0–10 m) which was lost at larger scales (10–30 m). (3) The degree of spatial clumping deceases from saplings, to poles, to adults indicates that density-dependent mortality of the offspring is ubiquitous in <span class="hlt">species</span>. (4) It is notable that a high number of positive small-scale interactions were found among the twenty <span class="hlt">species</span>. For saplings, 42.6% of all combinations of <span class="hlt">species</span> pairs showed positive associations at neighborhood scales up to five meters, but only 38.4% were negative. For poles and adults, positive associations at these distances still made up 45.5% and 29.5%, respectively. In conclusion, there is considerable evidence for the presence of positive interactions among the <span class="hlt">tree</span> <span class="hlt">species</span>, which suggests that <span class="hlt">species</span> herd protection may occur in our plot. In addition, niche assembly and limited dispersal (likely) contribute to the spatial patterns of <span class="hlt">tree</span> <span class="hlt">species</span> in the tropical seasonal rain forest in Xishuangbanna, China. PMID:23029394</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/12625013','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/12625013"><span id="translatedtitle">[Feasibility to introduce rare <span class="hlt">tree</span> <span class="hlt">species</span> Pinus sibirica into China].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Guifeng; Yang, Chuanping; Zhao, Guangyi</p> <p>2002-11-01</p> <p>Pinus sibirica growing mainly in Siberia of Russia is distributed over the Euro-Asia Taiga forest belt. There are many high-quality populations due to a great deal of variations. This kind of <span class="hlt">tree</span> has an advantage of standing up to frigid environment, and can spread out in such places that have cold weather and high altitude. In China, boreal forest is a wide-spreaded type of forest that has the largest area and high volume. For this reason, it is feasible to introduce Pinus sibirica into the region that the condition is suitable. Introducing this kind of <span class="hlt">tree</span> is a strategic project that can improve the structure and quality of our boreal forest. Introducing it can not only meet the demands of improved variety in short time, but also do the experiment of producing edible seeds and build up the developing center of nut, which can be a way of getting rid of poverty of forest region in heavy frigid area where is regarded as infertile area for farming formerly. PMID:12625013</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26364482','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26364482"><span id="translatedtitle">Fuel wood properties of some oak <span class="hlt">tree</span> <span class="hlt">species</span> of Manipur, India.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Meetei, Shougrakpam Bijen; Singh, E J; Das, Ashesh Kumar</p> <p>2015-07-01</p> <p>Five indigenous oak <span class="hlt">tree</span> <span class="hlt">species</span>, i.e., Castanopsis indica (Roxb. ex Lindl.) A.DC., Lithocarpus fenestratus (Roxb.) Rehder, Lithocarpus pachyphyllus (Kurz) Rehder, Lithocarpus polystachyus (Wall. ex A.DC.) Rehder and Quercus serrata Murray were estimated for their wood properties such as calorific value, density, moisture content and ash content from a sub-tropical forest of Haraothel hill, Senapati District, Manipur. Wood biomass components were found to have higher calorific value (kJ g(-)) than bark components. The calorific values for <span class="hlt">tree</span> <span class="hlt">species</span> were found highest in L. pachyphyllus (17.99 kJ g(-1)) followed by C. indica (17.98 kJ g1), L. fenestratus (17.96 kJ g"), L. polystachyus (17.80 kJ g(-1)) and Q. serrata (17.49 kJ g(-1)). Calorific values for bole bark, bole wood and branch bark were found significantly different (F > 3.48 at p = 0.05) in five oak <span class="hlt">tree</span> <span class="hlt">species</span>. Percentage of ash on dry weight basis was found to be highest in Q. serrata (4.73%) and lowest in C. indica (2.19%). Ash content of <span class="hlt">tree</span> components gives a singnificant factor in determining fuelwood value index (FVI). Of all the five oak <span class="hlt">tree</span> <span class="hlt">species</span>, Q. serrata exhibited highest value of wood density (0.78 g cm-) and lowest was observed in C. indica (0.63 g cm(-3)). There was significant correlation between wood density (p<0.05), ash content (p<0.01) with calorific value in oak <span class="hlt">tree</span> <span class="hlt">species</span>. Fuelwood value index (FVI) was in the following order: C. indica (1109.70) > L. pachyphyllus (898.41)> L. polystachyus (879.02)> L. fenestratus (824.61)> Q. serrata (792.50). Thus, the present study suggests that C. indica may be considered as a fuelwood oak <span class="hlt">tree</span> <span class="hlt">species</span> in Manipur. PMID:26364482</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4988811','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4988811"><span id="translatedtitle">Early establishment of <span class="hlt">trees</span> at the alpine treeline: idiosyncratic <span class="hlt">species</span> responses to temperature-moisture interactions</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Loranger, Hannah; Zotz, Gerhard; Bader, Maaike Y.</p> <p>2016-01-01</p> <p>On a global scale, temperature is the main determinant of arctic and alpine treeline position. However on a local scale, treeline form and position vary considerably due to other climatic factors, <span class="hlt">tree</span> <span class="hlt">species</span> ecology and life-stage-dependent responses. For treelines to advance poleward or uphill, the first steps are germination and seedling establishment. These earliest life stages may be major bottlenecks for treeline <span class="hlt">tree</span> populations and will depend differently on climatic conditions than adult <span class="hlt">trees</span>. We investigated the effect of soil temperature and moisture on germination and early seedling survival in a field experiment in the French Alps near the local treeline (2100 m a.s.l.) using passive temperature manipulations and two watering regimes. Five European treeline <span class="hlt">tree</span> <span class="hlt">species</span> were studied: Larix decidua, Picea abies, Pinus cembra, Pinus uncinata and Sorbus aucuparia. In addition, we monitored the germination response of three of these <span class="hlt">species</span> to low temperatures under controlled conditions in growth chambers. The early establishment of these <span class="hlt">trees</span> at the alpine treeline was limited either by temperature or by moisture, the sensitivity to one factor often depending on the intensity of the other. The results showed that the relative importance of the two factors and the direction of the effects are highly <span class="hlt">species</span>-specific, while both factors tend to have consistent effects on both germination and early seedling survival within each <span class="hlt">species</span>. We show that temperature and water availability are both important contributors to establishment patterns of treeline <span class="hlt">trees</span> and hence to <span class="hlt">species</span>-specific forms and positions of alpine treelines. The observed idiosyncratic <span class="hlt">species</span> responses highlight the need for studies including several <span class="hlt">species</span> and life-stages to create predictive power concerning future treeline dynamics. PMID:27402618</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27402618','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27402618"><span id="translatedtitle">Early establishment of <span class="hlt">trees</span> at the alpine treeline: idiosyncratic <span class="hlt">species</span> responses to temperature-moisture interactions.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Loranger, Hannah; Zotz, Gerhard; Bader, Maaike Y</p> <p>2016-01-01</p> <p>On a global scale, temperature is the main determinant of arctic and alpine treeline position. However on a local scale, treeline form and position vary considerably due to other climatic factors, <span class="hlt">tree</span> <span class="hlt">species</span> ecology and life-stage-dependent responses. For treelines to advance poleward or uphill, the first steps are germination and seedling establishment. These earliest life stages may be major bottlenecks for treeline <span class="hlt">tree</span> populations and will depend differently on climatic conditions than adult <span class="hlt">trees</span>. We investigated the effect of soil temperature and moisture on germination and early seedling survival in a field experiment in the French Alps near the local treeline (2100 m a.s.l.) using passive temperature manipulations and two watering regimes. Five European treeline <span class="hlt">tree</span> <span class="hlt">species</span> were studied: Larix decidua, Picea abies, Pinus cembra, Pinus uncinata and Sorbus aucuparia In addition, we monitored the germination response of three of these <span class="hlt">species</span> to low temperatures under controlled conditions in growth chambers. The early establishment of these <span class="hlt">trees</span> at the alpine treeline was limited either by temperature or by moisture, the sensitivity to one factor often depending on the intensity of the other. The results showed that the relative importance of the two factors and the direction of the effects are highly <span class="hlt">species</span>-specific, while both factors tend to have consistent effects on both germination and early seedling survival within each <span class="hlt">species</span>. We show that temperature and water availability are both important contributors to establishment patterns of treeline <span class="hlt">trees</span> and hence to <span class="hlt">species</span>-specific forms and positions of alpine treelines. The observed idiosyncratic <span class="hlt">species</span> responses highlight the need for studies including several <span class="hlt">species</span> and life-stages to create predictive power concerning future treeline dynamics. PMID:27402618</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25377453','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25377453"><span id="translatedtitle">Multiple <span class="hlt">species</span> of wild <span class="hlt">tree</span> peonies gave rise to the 'king of flowers', Paeonia suffruticosa Andrews.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhou, Shi-Liang; Zou, Xin-Hui; Zhou, Zhi-Qin; Liu, Jing; Xu, Chao; Yu, Jing; Wang, Qiang; Zhang, Da-Ming; Wang, Xiao-Quan; Ge, Song; Sang, Tao; Pan, Kai-Yu; Hong, De-Yuan</p> <p>2014-12-22</p> <p>The origin of cultivated <span class="hlt">tree</span> peonies, known as the 'king of flowers' in China for more than 1000 years, has attracted considerable interest, but remained unsolved. Here, we conducted phylogenetic analyses of explicitly sampled traditional cultivars of <span class="hlt">tree</span> peonies and all wild <span class="hlt">species</span> from the shrubby section Moutan of the genus Paeonia based on sequences of 14 fast-evolved chloroplast regions and 25 presumably single-copy nuclear markers identified from RNA-seq data. The phylogeny of the wild <span class="hlt">species</span> inferred from the nuclear markers was fully resolved and largely congruent with morphology and classification. The incongruence between the nuclear and chloroplast <span class="hlt">trees</span> suggested that there had been gene flow between the wild <span class="hlt">species</span>. The comparison of nuclear and chloroplast phylogenies including cultivars showed that the cultivated <span class="hlt">tree</span> peonies originated from homoploid hybridization among five wild <span class="hlt">species</span>. Since the origin, thousands of cultivated varieties have spread worldwide, whereas four parental <span class="hlt">species</span> are currently endangered or on the verge of extinction. The documentation of extensive homoploid hybridization involved in <span class="hlt">tree</span> peony domestication provides new insights into the mechanisms underlying the origins of garden ornamentals and the way of preserving natural genetic resources through domestication. PMID:25377453</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3436813','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3436813"><span id="translatedtitle">Inferring duplications, losses, transfers and incomplete lineage sorting with nonbinary <span class="hlt">species</span> <span class="hlt">trees</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Stolzer, Maureen; Lai, Han; Xu, Minli; Sathaye, Deepa; Vernot, Benjamin; Durand, Dannie</p> <p>2012-01-01</p> <p>Motivation: Gene duplication (D), transfer (T), loss (L) and incomplete lineage sorting (I) are crucial to the evolution of gene families and the emergence of novel functions. The history of these events can be inferred via comparison of gene and <span class="hlt">species</span> <span class="hlt">trees</span>, a process called reconciliation, yet current reconciliation algorithms model only a subset of these evolutionary processes. Results: We present an algorithm to reconcile a binary gene <span class="hlt">tree</span> with a nonbinary <span class="hlt">species</span> <span class="hlt">tree</span> under a DTLI parsimony criterion. This is the first reconciliation algorithm to capture all four evolutionary processes driving <span class="hlt">tree</span> incongruence and the first to reconcile non-binary <span class="hlt">species</span> <span class="hlt">trees</span> with a transfer model. Our algorithm infers all optimal solutions and reports complete, temporally feasible event histories, giving the gene and <span class="hlt">species</span> lineages in which each event occurred. It is fixed-parameter tractable, with polytime complexity when the maximum <span class="hlt">species</span> outdegree is fixed. Application of our algorithms to prokaryotic and eukaryotic data show that use of an incomplete event model has substantial impact on the events inferred and resulting biological conclusions. Availability: Our algorithms have been implemented in Notung, a freely available phylogenetic reconciliation software package, available at http://www.cs.cmu.edu/~durand/Notung. Contact: mstolzer@andrew.cmu.edu PMID:22962460</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4657984','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4657984"><span id="translatedtitle">Discrimination of Deciduous <span class="hlt">Tree</span> <span class="hlt">Species</span> from Time Series of Unmanned Aerial System Imagery</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lisein, Jonathan; Michez, Adrien; Claessens, Hugues; Lejeune, Philippe</p> <p>2015-01-01</p> <p>Technology advances can revolutionize Precision Forestry by providing accurate and fine forest information at <span class="hlt">tree</span> level. This paper addresses the question of how and particularly when Unmanned Aerial System (UAS) should be used in order to efficiently discriminate deciduous <span class="hlt">tree</span> <span class="hlt">species</span>. The goal of this research is to determine when is the best time window to achieve an optimal <span class="hlt">species</span> discrimination. A time series of high resolution UAS imagery was collected to cover the growing season from leaf flush to leaf fall. Full benefit was taken of the temporal resolution of UAS acquisition, one of the most promising features of small drones. The disparity in forest <span class="hlt">tree</span> phenology is at the maximum during early spring and late autumn. But the phenology state that optimized the classification result is the one that minimizes the spectral variation within <span class="hlt">tree</span> <span class="hlt">species</span> groups and, at the same time, maximizes the phenologic differences between <span class="hlt">species</span>. Sunlit <span class="hlt">tree</span> crowns (5 deciduous <span class="hlt">species</span> groups) were classified using a Random Forest approach for monotemporal, two-date and three-date combinations. The end of leaf flushing was the most efficient single-date time window. Multitemporal datasets definitely improve the overall classification accuracy. But single-date high resolution orthophotomosaics, acquired on optimal time-windows, result in a very good classification accuracy (overall out of bag error of 16%). PMID:26600422</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26600422','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26600422"><span id="translatedtitle">Discrimination of Deciduous <span class="hlt">Tree</span> <span class="hlt">Species</span> from Time Series of Unmanned Aerial System Imagery.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lisein, Jonathan; Michez, Adrien; Claessens, Hugues; Lejeune, Philippe</p> <p>2015-01-01</p> <p>Technology advances can revolutionize Precision Forestry by providing accurate and fine forest information at <span class="hlt">tree</span> level. This paper addresses the question of how and particularly when Unmanned Aerial System (UAS) should be used in order to efficiently discriminate deciduous <span class="hlt">tree</span> <span class="hlt">species</span>. The goal of this research is to determine when is the best time window to achieve an optimal <span class="hlt">species</span> discrimination. A time series of high resolution UAS imagery was collected to cover the growing season from leaf flush to leaf fall. Full benefit was taken of the temporal resolution of UAS acquisition, one of the most promising features of small drones. The disparity in forest <span class="hlt">tree</span> phenology is at the maximum during early spring and late autumn. But the phenology state that optimized the classification result is the one that minimizes the spectral variation within <span class="hlt">tree</span> <span class="hlt">species</span> groups and, at the same time, maximizes the phenologic differences between <span class="hlt">species</span>. Sunlit <span class="hlt">tree</span> crowns (5 deciduous <span class="hlt">species</span> groups) were classified using a Random Forest approach for monotemporal, two-date and three-date combinations. The end of leaf flushing was the most efficient single-date time window. Multitemporal datasets definitely improve the overall classification accuracy. But single-date high resolution orthophotomosaics, acquired on optimal time-windows, result in a very good classification accuracy (overall out of bag error of 16%). PMID:26600422</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4604832','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4604832"><span id="translatedtitle">PoMo: An Allele Frequency-Based Approach for <span class="hlt">Species</span> <span class="hlt">Tree</span> Estimation</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>De Maio, Nicola; Schrempf, Dominik; Kosiol, Carolin</p> <p>2015-01-01</p> <p>Incomplete lineage sorting can cause incongruencies of the overall <span class="hlt">species</span>-level phylogenetic <span class="hlt">tree</span> with the phylogenetic <span class="hlt">trees</span> for individual genes or genomic segments. If these incongruencies are not accounted for, it is possible to incur several biases in <span class="hlt">species</span> <span class="hlt">tree</span> estimation. Here, we present a simple maximum likelihood approach that accounts for ancestral variation and incomplete lineage sorting. We use a POlymorphisms-aware phylogenetic MOdel (PoMo) that we have recently shown to efficiently estimate mutation rates and fixation biases from within and between-<span class="hlt">species</span> variation data. We extend this model to perform efficient estimation of <span class="hlt">species</span> <span class="hlt">trees</span>. We test the performance of PoMo in several different scenarios of incomplete lineage sorting using simulations and compare it with existing methods both in accuracy and computational speed. In contrast to other approaches, our model does not use coalescent theory but is allele frequency based. We show that PoMo is well suited for genome-wide <span class="hlt">species</span> <span class="hlt">tree</span> estimation and that on such data it is more accurate than previous approaches. PMID:26209413</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21910838','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21910838"><span id="translatedtitle">Fruit availability, frugivore satiation and seed removal in 2 primate-dispersed <span class="hlt">tree</span> <span class="hlt">species</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ratiarison, Sandra; Forget, Pierre-Michel</p> <p>2011-09-01</p> <p>During a mast-fruiting event we investigated spatial variability in fruit availability, consumption, and seed removal at two sympatric <span class="hlt">tree</span> <span class="hlt">species</span>, Manilkara bidentata and M. huberi (Sapotaceae) at Nouragues Natural Reserve, French Guiana. We addressed the question of how Manilkara density and fruits at the community level might be major causes of variability in feeding assemblages between <span class="hlt">tree</span> <span class="hlt">species</span>. We thus explored how the frugivore assemblages differed between forest patches with contrasting relative Manilkara density and fruiting context. During the daytime, Alouatta seniculus was more often observed in M. huberi crowns at Petit Plateau (PP) with the greatest density of Manilkara spp. and the lowest fruit diversity and availability, whereas Cebus apella and Saguinus midas were more often observed in M. bidentata crowns at both Grand Plateau (GP), with a lowest density of M. bidentata and overall greater fruit supply, and PP. Overall, nearly 53% and 15% of the M. bidentata seed crop at GP and PP, respectively, and about 47% of the M. huberi seed crop were removed, otherwise either spit out or defecated beneath <span class="hlt">trees</span>, or dropped in fruits. Small-bodied primates concentrated fallen seeds beneath parent <span class="hlt">trees</span> while large-bodied primate <span class="hlt">species</span> removed and dispersed more seeds away from parents. However, among the latter, satiated A. seniculus wasted seeds under conspecific <span class="hlt">trees</span> at PP. Variations in feeding assemblages, seed removal rates and fates possibly reflected interactions with extra-generic fruit <span class="hlt">species</span> at the community level, according to feeding choice, habitat preferences and ranging patterns of primate <span class="hlt">species</span>. PMID:21910838</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.treesearch.fs.fed.us/pubs/4893','USGSPUBS'); return false;" href="http://www.treesearch.fs.fed.us/pubs/4893"><span id="translatedtitle">Supplemental planting of early successional <span class="hlt">tree</span> <span class="hlt">species</span> during bottomland hardwood afforestation</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Twedt, D.J.; Wilson, R.R.</p> <p>2002-01-01</p> <p>Reforestation of former bottom land hardwood forests that have been cleared for agriculture (i.e., afforestation) has historically emphasized planting heavy-seeded oaks (Quercus spp.) and pecans (Carya spp.). These <span class="hlt">species</span> are slow to develop vertical forest structure. However, vertical forest structure is key to colonization of afforested sites by forest birds. Although early-successional <span class="hlt">tree</span> <span class="hlt">species</span> often enhance vertical structure, few of these <span class="hlt">species</span> invade afforested sites that are distant from seed sources. Furthermore, many land mangers are reluctant to establish and maintain stands of fast-growing plantation <span class="hlt">trees</span>. Therefore, on 40 afforested bottomland sites, we supplemented heavy-seeded seedlings with 8 patches of fast-growing <span class="hlt">trees</span>: 4 patches of 12 eastern cottonwood (Populus deltoides) stem cuttings and 4 patches of 12 American sycamore (Platanus occidentalis) seedlings. To enhance survival and growth, <span class="hlt">tree</span> patches were subjected to 4 weed control treatments: (1) physical weed barriers, (2) chemical herbicide, (3) both physical and chemical weed control, or (4) no weed control. Overall, first-year survival of cottonwood and sycamore was 25 percent and 47 percent, respectively. Second-year survival of extant <span class="hlt">trees</span> was 52 percent for cottonwood and 77 percent for sycamore. Physical weed barriers increased survival of cottonwoods to 30 percent versus 18 percent survival with no weed control. Similarly, sycamore survival was increased from 49 percent without weed control to 64 percent with physical weed barriers. Chemical weed control adversely impacted sycamore and reduced survival to 35 percent. <span class="hlt">Tree</span> heights did not differ between <span class="hlt">species</span> or among weed control treatments. Girdling of <span class="hlt">trees</span> by deer often destroyed saplings. Thus, little increase in vertical structure was detected between growing seasons. Application of fertilizer and protection via <span class="hlt">tree</span> shelters did not improve survival or vertical development of sycamore or cottonwood.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1461003','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1461003"><span id="translatedtitle">Effects of colonization processes on genetic diversity: differences between annual plants and <span class="hlt">tree</span> <span class="hlt">species</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Austerlitz, F; Mariette, S; Machon, N; Gouyon, P H; Godelle, B</p> <p>2000-01-01</p> <p><span class="hlt">Tree</span> <span class="hlt">species</span> are striking for their high within-population diversity and low among-population differentiation for nuclear genes. In contrast, annual plants show much more differentiation for nuclear genes but much less diversity than <span class="hlt">trees</span>. The usual explanation for this difference is that pollen flow, and therefore gene flow, is much higher for <span class="hlt">trees</span>. This explanation is problematic because it relies on equilibrium hypotheses. Because <span class="hlt">trees</span> have very recently recolonized temperate areas, they have experienced many foundation events, which usually reduce within-population diversity and increase differentiation. Only extremely high levels of gene flow could counterbalance these successive founder effects. We develop a model to study the impact of life cycle of forest <span class="hlt">trees</span>, in particular of the length of their juvenile phase, on genetic diversity and differentiation during the glacial period and the following colonization period. We show that both a reasonably high level of pollen flow and the life-cycle characteristics of <span class="hlt">trees</span> are needed to explain the observed structure of genetic diversity. We also show that gene flow and life cycle both have an impact on maternally inherited cytoplasmic genes, which are characterized both in <span class="hlt">trees</span> and annual <span class="hlt">species</span> by much less diversity and much more differentiation than nuclear genes. PMID:10757772</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26153693','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26153693"><span id="translatedtitle">Operational <span class="hlt">Tree</span> <span class="hlt">Species</span> Mapping in a Diverse Tropical Forest with Airborne Imaging Spectroscopy.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Baldeck, Claire A; Asner, Gregory P; Martin, Robin E; Anderson, Christopher B; Knapp, David E; Kellner, James R; Wright, S Joseph</p> <p>2015-01-01</p> <p>Remote identification and mapping of canopy <span class="hlt">tree</span> <span class="hlt">species</span> can contribute valuable information towards our understanding of ecosystem biodiversity and function over large spatial scales. However, the extreme challenges posed by highly diverse, closed-canopy tropical forests have prevented automated remote <span class="hlt">species</span> mapping of non-flowering <span class="hlt">tree</span> crowns in these ecosystems. We set out to identify individuals of three focal canopy <span class="hlt">tree</span> <span class="hlt">species</span> amongst a diverse background of <span class="hlt">tree</span> and liana <span class="hlt">species</span> on Barro Colorado Island, Panama, using airborne imaging spectroscopy data. First, we compared two leading single-class classification methods--binary support vector machine (SVM) and biased SVM--for their performance in identifying pixels of a single focal <span class="hlt">species</span>. From this comparison we determined that biased SVM was more precise and created a multi-<span class="hlt">species</span> classification model by combining the three biased SVM models. This model was applied to the imagery to identify pixels belonging to the three focal <span class="hlt">species</span> and the prediction results were then processed to create a map of focal <span class="hlt">species</span> crown objects. Crown-level cross-validation of the training data indicated that the multi-<span class="hlt">species</span> classification model had pixel-level producer's accuracies of 94-97% for the three focal <span class="hlt">species</span>, and field validation of the predicted crown objects indicated that these had user's accuracies of 94-100%. Our results demonstrate the ability of high spatial and spectral resolution remote sensing to accurately detect non-flowering crowns of focal <span class="hlt">species</span> within a diverse tropical forest. We attribute the success of our model to recent classification and mapping techniques adapted to <span class="hlt">species</span> detection in diverse closed-canopy forests, which can pave the way for remote <span class="hlt">species</span> mapping in a wider variety of ecosystems. PMID:26153693</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4496029','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4496029"><span id="translatedtitle">Operational <span class="hlt">Tree</span> <span class="hlt">Species</span> Mapping in a Diverse Tropical Forest with Airborne Imaging Spectroscopy</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Baldeck, Claire A.; Asner, Gregory P.; Martin, Robin E.; Anderson, Christopher B.; Knapp, David E.; Kellner, James R.; Wright, S. Joseph</p> <p>2015-01-01</p> <p>Remote identification and mapping of canopy <span class="hlt">tree</span> <span class="hlt">species</span> can contribute valuable information towards our understanding of ecosystem biodiversity and function over large spatial scales. However, the extreme challenges posed by highly diverse, closed-canopy tropical forests have prevented automated remote <span class="hlt">species</span> mapping of non-flowering <span class="hlt">tree</span> crowns in these ecosystems. We set out to identify individuals of three focal canopy <span class="hlt">tree</span> <span class="hlt">species</span> amongst a diverse background of <span class="hlt">tree</span> and liana <span class="hlt">species</span> on Barro Colorado Island, Panama, using airborne imaging spectroscopy data. First, we compared two leading single-class classification methods—binary support vector machine (SVM) and biased SVM—for their performance in identifying pixels of a single focal <span class="hlt">species</span>. From this comparison we determined that biased SVM was more precise and created a multi-<span class="hlt">species</span> classification model by combining the three biased SVM models. This model was applied to the imagery to identify pixels belonging to the three focal <span class="hlt">species</span> and the prediction results were then processed to create a map of focal <span class="hlt">species</span> crown objects. Crown-level cross-validation of the training data indicated that the multi-<span class="hlt">species</span> classification model had pixel-level producer’s accuracies of 94–97% for the three focal <span class="hlt">species</span>, and field validation of the predicted crown objects indicated that these had user’s accuracies of 94–100%. Our results demonstrate the ability of high spatial and spectral resolution remote sensing to accurately detect non-flowering crowns of focal <span class="hlt">species</span> within a diverse tropical forest. We attribute the success of our model to recent classification and mapping techniques adapted to <span class="hlt">species</span> detection in diverse closed-canopy forests, which can pave the way for remote <span class="hlt">species</span> mapping in a wider variety of ecosystems. PMID:26153693</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70041741','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70041741"><span id="translatedtitle">Quantifying <span class="hlt">tree</span> mortality in a mixed <span class="hlt">species</span> woodland using multitemporal high spatial resolution satellite imagery</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Garrity, Steven R.; Allen, Craig D.; Brumby, Steven P.; Gangodagamage, Chandana; McDowell, Nate G.; Cai, D. Michael</p> <p>2013-01-01</p> <p>Widespread <span class="hlt">tree</span> mortality events have recently been observed in several biomes. To effectively quantify the severity and extent of these events, tools that allow for rapid assessment at the landscape scale are required. Past studies using high spatial resolution satellite imagery have primarily focused on detecting green, red, and gray <span class="hlt">tree</span> canopies during and shortly after <span class="hlt">tree</span> damage or mortality has occurred. However, detecting <span class="hlt">trees</span> in various stages of death is not always possible due to limited availability of archived satellite imagery. Here we assess the capability of high spatial resolution satellite imagery for <span class="hlt">tree</span> mortality detection in a southwestern U.S. mixed <span class="hlt">species</span> woodland using archived satellite images acquired prior to mortality and well after dead <span class="hlt">trees</span> had dropped their leaves. We developed a multistep classification approach that uses: supervised masking of non-<span class="hlt">tree</span> image elements; bi-temporal (pre- and post-mortality) differencing of normalized difference vegetation index (NDVI) and red:green ratio (RGI); and unsupervised multivariate clustering of pixels into live and dead <span class="hlt">tree</span> classes using a Gaussian mixture model. Classification accuracies were improved in a final step by tuning the rules of pixel classification using the posterior probabilities of class membership obtained from the Gaussian mixture model. Classifications were produced for two images acquired post-mortality with overall accuracies of 97.9% and 98.5%, respectively. Classified images were combined with land cover data to characterize the spatiotemporal characteristics of <span class="hlt">tree</span> mortality across areas with differences in <span class="hlt">tree</span> <span class="hlt">species</span> composition. We found that 38% of <span class="hlt">tree</span> crown area was lost during the drought period between 2002 and 2006. The majority of <span class="hlt">tree</span> mortality during this period was concentrated in piñon-juniper (Pinus edulis-Juniperus monosperma) woodlands. An additional 20% of the <span class="hlt">tree</span> canopy died or was removed between 2006 and 2011, primarily in areas</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/19880241','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/19880241"><span id="translatedtitle">Estimating <span class="hlt">tree</span> bole volume using artificial neural network models for four <span class="hlt">species</span> in Turkey.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ozçelik, Ramazan; Diamantopoulou, Maria J; Brooks, John R; Wiant, Harry V</p> <p>2010-01-01</p> <p><span class="hlt">Tree</span> bole volumes of 89 Scots pine (Pinus sylvestris L.), 96 Brutian pine (Pinus brutia Ten.), 107 Cilicica fir (Abies cilicica Carr.) and 67 Cedar of Lebanon (Cedrus libani A. Rich.) <span class="hlt">trees</span> were estimated using Artificial Neural Network (ANN) models. Neural networks offer a number of advantages including the ability to implicitly detect complex nonlinear relationships between input and output variables, which is very helpful in <span class="hlt">tree</span> volume modeling. Two different neural network architectures were used and produced the Back propagation (BPANN) and the Cascade Correlation (CCANN) Artificial Neural Network models. In addition, <span class="hlt">tree</span> bole volume estimates were compared to other established <span class="hlt">tree</span> bole volume estimation techniques including the centroid method, taper equations, and existing standard volume tables. An overview of the features of ANNs and traditional methods is presented and the advantages and limitations of each one of them are discussed. For validation purposes, actual volumes were determined by aggregating the volumes of measured short sections (average 1 meter) of the <span class="hlt">tree</span> bole using Smalian's formula. The results reported in this research suggest that the selected cascade correlation artificial neural network (CCANN) models are reliable for estimating the <span class="hlt">tree</span> bole volume of the four examined <span class="hlt">tree</span> <span class="hlt">species</span> since they gave unbiased results and were superior to almost all methods in terms of error (%) expressed as the mean of the percentage errors. PMID:19880241</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ISPAnII22..175M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ISPAnII22..175M"><span id="translatedtitle">Identification and Mapping of <span class="hlt">Tree</span> <span class="hlt">Species</span> in Urban Areas Using WORLDVIEW-2 Imagery</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mustafa, Y. T.; Habeeb, H. N.; Stein, A.; Sulaiman, F. Y.</p> <p>2015-10-01</p> <p>Monitoring and mapping of urban <span class="hlt">trees</span> are essential to provide urban forestry authorities with timely and consistent information. Modern techniques increasingly facilitate these tasks, but require the development of semi-automatic <span class="hlt">tree</span> detection and classification methods. In this article, we propose an approach to delineate and map the crown of 15 <span class="hlt">tree</span> <span class="hlt">species</span> in the city of Duhok, Kurdistan Region of Iraq using WorldView-2 (WV-2) imagery. A <span class="hlt">tree</span> crown object is identified first and is subsequently delineated as an image object (IO) using vegetation indices and texture measurements. Next, three classification methods: Maximum Likelihood, Neural Network, and Support Vector Machine were used to classify IOs using selected IO features. The best results are obtained with Support Vector Machine classification that gives the best map of urban <span class="hlt">tree</span> <span class="hlt">species</span> in Duhok. The overall accuracy was between 60.93% to 88.92% and κ-coefficient was between 0.57 to 0.75. We conclude that fifteen <span class="hlt">tree</span> <span class="hlt">species</span> were identified and mapped at a satisfactory accuracy in urban areas of this study.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/EJ1099325.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/EJ1099325.pdf"><span id="translatedtitle"><span class="hlt">Trees</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Al-Khaja, Nawal</p> <p>2007-01-01</p> <p>This is a thematic lesson plan for young learners about palm <span class="hlt">trees</span> and the importance of taking care of them. The two part lesson teaches listening, reading and speaking skills. The lesson includes parts of a <span class="hlt">tree</span>; the modal auxiliary, can; dialogues and a role play activity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.9592I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.9592I"><span id="translatedtitle">The response of European <span class="hlt">tree</span> <span class="hlt">species</span> to drought: a meta-analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Irschick, C.; Mayr, S.; Wohlfahrt, G.</p> <p>2012-04-01</p> <p>Here we provide first results of a meta-analysis of the response of European <span class="hlt">tree</span> <span class="hlt">species</span> to drought. A literature search was conducted in order to collect available studies of the response of the gas exchange of European <span class="hlt">tree</span> <span class="hlt">species</span> to either natural or imposed water shortage. The resulting publications were screened and parameters at organ (e.g. leaf or shoot), individual (i.e. <span class="hlt">tree</span>) and ecosystem scale were transferred to a data base. Here we present preliminary results from queries of the data base aiming at identifying differences in the drought response between <span class="hlt">species</span> that may have implications for forest productivity and composition under likely future warmer and drier conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4840356','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4840356"><span id="translatedtitle">Warming effects on photosynthesis of subtropical <span class="hlt">tree</span> <span class="hlt">species</span>: a translocation experiment along an altitudinal gradient</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Li, Yiyong; Liu, Juxiu; Zhou, Guoyi; Huang, Wenjuan; Duan, Honglang</p> <p>2016-01-01</p> <p>Ongoing climate warming induced by human activities may have great impacts on <span class="hlt">trees</span>, yet it remains unresolved how subtropical <span class="hlt">tree</span> <span class="hlt">species</span> respond to rising temperature in the field. Here, we used downward translocation to investigate the effects of climate warming on leaf photosynthesis of six common <span class="hlt">tree</span> <span class="hlt">species</span> in subtropical China. During the experimental period between 2012 and 2014, the mean average photosynthetic rates (Asat) under saturating light for Schima superba, Machilus breviflora, Pinus massoniana and Ardisia lindleyana in the warm site were7%, 19%, 20% and 29% higher than those in the control site. In contrast, seasonal Asat for Castanopsis hystrix in the warm site were lower compared to the control site. Changes in Asat in response to translocation were mainly associated with those in leaf stomatal conductance (gs) and photosynthetic capacity (RuBP carboxylation, RuBP regeneration capacity). Our results imply that climate warming could have potential impacts on <span class="hlt">species</span> composition and community structure in subtropical forests. PMID:27102064</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4021425','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4021425"><span id="translatedtitle">An empirical evaluation of two-stage <span class="hlt">species</span> <span class="hlt">tree</span> inference strategies using a multilocus dataset from North American pines</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2014-01-01</p> <p>Background As it becomes increasingly possible to obtain DNA sequences of orthologous genes from diverse sets of taxa, <span class="hlt">species</span> <span class="hlt">trees</span> are frequently being inferred from multilocus data. However, the behavior of many methods for performing this inference has remained largely unexplored. Some methods have been proven to be consistent given certain evolutionary models, whereas others rely on criteria that, although appropriate for many parameter values, have peculiar zones of the parameter space in which they fail to converge on the correct estimate as data sets increase in size. Results Here, using North American pines, we empirically evaluate the behavior of 24 strategies for <span class="hlt">species</span> <span class="hlt">tree</span> inference using three alternative outgroups (72 strategies total). The data consist of 120 individuals sampled in eight ingroup <span class="hlt">species</span> from subsection Strobus and three outgroup <span class="hlt">species</span> from subsection Gerardianae, spanning ∼47 kilobases of sequence at 121 loci. Each “strategy” for inferring <span class="hlt">species</span> <span class="hlt">trees</span> consists of three features: a <span class="hlt">species</span> <span class="hlt">tree</span> construction method, a gene <span class="hlt">tree</span> inference method, and a choice of outgroup. We use multivariate analysis techniques such as principal components analysis and hierarchical clustering to identify <span class="hlt">tree</span> characteristics that are robustly observed across strategies, as well as to identify groups of strategies that produce <span class="hlt">trees</span> with similar features. We find that strategies that construct <span class="hlt">species</span> <span class="hlt">trees</span> using only topological information cluster together and that strategies that use additional non-topological information (e.g., branch lengths) also cluster together. Strategies that utilize more than one individual within a <span class="hlt">species</span> to infer gene <span class="hlt">trees</span> tend to produce estimates of <span class="hlt">species</span> <span class="hlt">trees</span> that contain clades present in <span class="hlt">trees</span> estimated by other strategies. Strategies that use the minimize-deep-coalescences criterion to construct <span class="hlt">species</span> <span class="hlt">trees</span> tend to produce <span class="hlt">species</span> <span class="hlt">tree</span> estimates that contain clades that are not present in <span class="hlt">trees</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27348264','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27348264"><span id="translatedtitle">The role of selected <span class="hlt">tree</span> <span class="hlt">species</span> in industrial sewage sludge/flotation tailing management.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mleczek, Mirosław; Rutkowski, Paweł; Niedzielski, Przemysław; Goliński, Piotr; Gąsecka, Monika; Kozubik, Tomisław; Dąbrowski, Jędrzej; Budzyńska, Sylwia; Pakuła, Jarosław</p> <p>2016-11-01</p> <p>The aim of the study was to estimate the ability of ten <span class="hlt">tree</span> and bush <span class="hlt">species</span> to tolerate and accumulate Cd, Cu, Pb, Zn, and As <span class="hlt">species</span> [As(III), As(V), and total organic arsenic] in industrial sewage sludge extremely contaminated with arsenic (almost 27.5 g kg(-1)) in a pot experiment. The premise being that it will then be possible to select the most promising <span class="hlt">tree</span>/bush <span class="hlt">species</span>, able to grow in the vicinity of dams where sewage sludge/flotation tailings are used as landfill. Six of the ten tested <span class="hlt">tree</span> <span class="hlt">species</span> were able to grow on the sludge. The highest content of total As was observed in Betula pendula roots (30.0 ± 1.3 mg kg(-1) DW), where the dominant As <span class="hlt">species</span> was the toxic As(V). The highest biomass of Quercus Q1 robur (77.3 § 2.6 g) and Acer platanoides (76.0 § 4.9 g) was observed. A proper planting of selected <span class="hlt">tree</span> <span class="hlt">species</span> that are able to thrive on sewage sludge/flotation tailings could be an interesting and promising way to protect dams. By utilizing differences in their root systems and water needs, we will be able to reduce the risk of fatal environmental disasters. PMID:27348264</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24620581','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24620581"><span id="translatedtitle">Diversity and utilization of <span class="hlt">tree</span> <span class="hlt">species</span> in Meitei homegardens of Barak Valley, Assam.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Devi, N Linthoingambi; Das, Ashesh Kumar</p> <p>2013-03-01</p> <p>An inventory of <span class="hlt">tree</span> diversity in traditional homegardens of Meitei community was conducted in a Bontarapur village in Cachar district of Barak Valley, Assam. Meitei homegarden locally called Ingkhol exhibits a wide diversity in size, shape, location and composition. Seventy one <span class="hlt">tree</span> <span class="hlt">species</span> were enumerated from 50 homegardens belonging to 60 genus and 35 families. Among the families encountered, Rutaceae was the dominant family (4 genus and 7 <span class="hlt">species</span>) followed by Meliaceae (5 genus and 5 <span class="hlt">species</span>), Arecaceae (4 genus and 4 <span class="hlt">species</span>) and Moraceae (3 genus and 5 <span class="hlt">species</span>). Total 7946 <span class="hlt">tree</span> individuals were recorded, with the density of 831 No ha(-1) of and total basal area of 9.54 m2 ha(-1). Areco catechu was the dominant <span class="hlt">species</span> with the maximum number of individuals. Other dominant <span class="hlt">trees</span> include Mangifera indica, Artocarpus heterophyllus, Citrus grandis, Parkia timoriana, Syzygium cumini and Psidium guajava. Being a cash crop, the intensification of betel nut has been preferred in many homegardens. Homegardens form an important component of land use of Meitei community which fulfills the socio-cultural and economic needs of the family and helps in conserving plant diversity through utilization. PMID:24620581</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25058660','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25058660"><span id="translatedtitle">Negative density dependence regulates two <span class="hlt">tree</span> <span class="hlt">species</span> at later life stage in a temperate forest.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Piao, Tiefeng; Chun, Jung Hwa; Yang, Hee Moon; Cheon, Kwangil</p> <p>2014-01-01</p> <p>Numerous studies have demonstrated that <span class="hlt">tree</span> survival is influenced by negative density dependence (NDD) and differences among <span class="hlt">species</span> in shade tolerance could enhance coexistence via resource partitioning, but it is still unclear how NDD affects <span class="hlt">tree</span> <span class="hlt">species</span> with different shade-tolerance guilds at later life stages. In this study, we analyzed the spatial patterns for <span class="hlt">trees</span> with dbh (diameter at breast height) ≥2 cm using the pair-correlation g(r) function to test for NDD in a temperate forest in South Korea after removing the effects of habitat heterogeneity. The analyses were implemented for the most abundant shade-tolerant (Chamaecyparis obtusa) and shade-intolerant (Quercus serrata) <span class="hlt">species</span>. We found NDD existed for both <span class="hlt">species</span> at later life stages. We also found Quercus serrata experienced greater NDD compared with Chamaecyparis obtusa. This study indicates that NDD regulates the two abundant <span class="hlt">tree</span> <span class="hlt">species</span> at later life stages and it is important to consider variation in <span class="hlt">species</span>' shade tolerance in NDD study. PMID:25058660</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70028562','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70028562"><span id="translatedtitle">Effects of sample survey design on the accuracy of classification <span class="hlt">tree</span> models in <span class="hlt">species</span> distribution models</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Edwards, T.C., Jr.; Cutler, D.R.; Zimmermann, N.E.; Geiser, L.; Moisen, G.G.</p> <p>2006-01-01</p> <p>We evaluated the effects of probabilistic (hereafter DESIGN) and non-probabilistic (PURPOSIVE) sample surveys on resultant classification <span class="hlt">tree</span> models for predicting the presence of four lichen <span class="hlt">species</span> in the Pacific Northwest, USA. Models derived from both survey forms were assessed using an independent data set (EVALUATION). Measures of accuracy as gauged by resubstitution rates were similar for each lichen <span class="hlt">species</span> irrespective of the underlying sample survey form. Cross-validation estimates of prediction accuracies were lower than resubstitution accuracies for all <span class="hlt">species</span> and both design types, and in all cases were closer to the true prediction accuracies based on the EVALUATION data set. We argue that greater emphasis should be placed on calculating and reporting cross-validation accuracy rates rather than simple resubstitution accuracy rates. Evaluation of the DESIGN and PURPOSIVE <span class="hlt">tree</span> models on the EVALUATION data set shows significantly lower prediction accuracy for the PURPOSIVE <span class="hlt">tree</span> models relative to the DESIGN models, indicating that non-probabilistic sample surveys may generate models with limited predictive capability. These differences were consistent across all four lichen <span class="hlt">species</span>, with 11 of the 12 possible <span class="hlt">species</span> and sample survey type comparisons having significantly lower accuracy rates. Some differences in accuracy were as large as 50%. The classification <span class="hlt">tree</span> structures also differed considerably both among and within the modelled <span class="hlt">species</span>, depending on the sample survey form. Overlap in the predictor variables selected by the DESIGN and PURPOSIVE <span class="hlt">tree</span> models ranged from only 20% to 38%, indicating the classification <span class="hlt">trees</span> fit the two evaluated survey forms on different sets of predictor variables. The magnitude of these differences in predictor variables throws doubt on ecological interpretation derived from prediction models based on non-probabilistic sample surveys. ?? 2006 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26094447','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26094447"><span id="translatedtitle">[Biomass allometric equations of nine common <span class="hlt">tree</span> <span class="hlt">species</span> in an evergreen broadleaved forest of subtropical China].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zuo, Shu-di; Ren, Yin; Weng, Xian; Ding, Hong-feng; Luo, Yun-jian</p> <p>2015-02-01</p> <p>Biomass allometric equation (BAE) considered as a simple and reliable method in the estimation of forest biomass and carbon was used widely. In China, numerous studies focused on the BAEs for coniferous forest and pure broadleaved forest, and generalized BAEs were frequently used to estimate the biomass and carbon of mixed broadleaved forest, although they could induce large uncertainty in the estimates. In this study, we developed the <span class="hlt">species</span>-specific and generalized BAEs using biomass measurement for 9 common broadleaved <span class="hlt">trees</span> (Castanopsis fargesii, C. lamontii, C. tibetana, Lithocarpus glaber, Sloanea sinensis, Daphniphyllum oldhami, Alniphyllum fortunei, Manglietia yuyuanensis, and Engelhardtia fenzlii) of subtropical evergreen broadleaved forest, and compared differences in <span class="hlt">species</span>-specific and generalized BAEs. The results showed that D (diameter at breast height) was a better independent variable in estimating the biomass of branch, leaf, root, aboveground section and total <span class="hlt">tree</span> than a combined variable (D2 H) of D and H (<span class="hlt">tree</span> height) , but D2H was better than D in estimating stem biomass. R2 (coefficient of determination) values of BAEs for 6 <span class="hlt">species</span> decreased when adding H as the second independent variable into D- only BAEs, where R2 value for S. sinensis decreased by 5.6%. Compared with generalized D- and D2H-based BAEs, standard errors of estimate (SEE) of BAEs for 8 <span class="hlt">tree</span> <span class="hlt">species</span> decreased, and similar decreasing trend was observed for different components, where SEEs of the branch decreased by 13.0% and 20.3%. Therefore, the biomass carbon storage and its dynamic estimates were influenced largely by <span class="hlt">tree</span> <span class="hlt">species</span> and model types. In order to improve the accuracy of the estimates of biomass and carbon, we should consider the differences in <span class="hlt">tree</span> <span class="hlt">species</span> and model types. PMID:26094447</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25371435','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25371435"><span id="translatedtitle">Toward more accurate ancestral protein genotype-phenotype reconstructions with the use of <span class="hlt">species</span> <span class="hlt">tree</span>-aware gene <span class="hlt">trees</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Groussin, Mathieu; Hobbs, Joanne K; Szöllősi, Gergely J; Gribaldo, Simonetta; Arcus, Vickery L; Gouy, Manolo</p> <p>2015-01-01</p> <p>The resurrection of ancestral proteins provides direct insight into how natural selection has shaped proteins found in nature. By tracing substitutions along a gene phylogeny, ancestral proteins can be reconstructed in silico and subsequently synthesized in vitro. This elegant strategy reveals the complex mechanisms responsible for the evolution of protein functions and structures. However, to date, all protein resurrection studies have used simplistic approaches for ancestral sequence reconstruction (ASR), including the assumption that a single sequence alignment alone is sufficient to accurately reconstruct the history of the gene family. The impact of such shortcuts on conclusions about ancestral functions has not been investigated. Here, we show with simulations that utilizing information on <span class="hlt">species</span> history using a model that accounts for the duplication, horizontal transfer, and loss (DTL) of genes statistically increases ASR accuracy. This underscores the importance of the <span class="hlt">tree</span> topology in the inference of putative ancestors. We validate our in silico predictions using in vitro resurrection of the LeuB enzyme for the ancestor of the Firmicutes, a major and ancient bacterial phylum. With this particular protein, our experimental results demonstrate that information on the <span class="hlt">species</span> phylogeny results in a biochemically more realistic and kinetically more stable ancestral protein. Additional resurrection experiments with different proteins are necessary to statistically quantify the impact of using <span class="hlt">species</span> <span class="hlt">tree</span>-aware gene <span class="hlt">trees</span> on ancestral protein phenotypes. Nonetheless, our results suggest the need for incorporating both sequence and DTL information in future studies of protein resurrections to accurately define the genotype-phenotype space in which proteins diversify. PMID:25371435</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24841715','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24841715"><span id="translatedtitle">Long-term differences in annual litter production between <span class="hlt">alien</span> (Sonneratia apetala) and native (Kandelia obovata) mangrove <span class="hlt">species</span> in Futian, Shenzhen, China.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Lina; Li, Fenglan; Yang, Qiong; Tam, Nora F Y; Liao, Wenbo; Zan, Qijie</p> <p>2014-08-30</p> <p>Annual litter production in <span class="hlt">alien</span> (Sonneratia apetala) and native (Kandelia obovata) mangrove forests in Shenzhen, China were compared from 1999 to 2010. S. apetala had significantly higher litter production than K. obovata, with mean annual total litter of 18.1 t ha(-1) yr(-1) and 15.2 t ha(-1) yr(-1), respectively. The higher litter production in S. apetala forest indicates higher productivity and consequently more nutrient supply to the estuarine ecosystems but may be more invasive due to positive plant-soil feedbacks and nutrient availability to this <span class="hlt">alien</span> <span class="hlt">species</span>. Two peaks were recorded in S. apetala (May and October), while only one peak was observed in K. obovata, in early spring (March and April). Leaf and reproductive materials were the main contributors to litter production (>80%) in both forests. These results suggest that the ecological function of S. apetala and its invasive potential can be better understood based on a long-term litter fall analysis. PMID:24841715</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.springerlink.com/content/g4295k8x56wj20g0/','USGSPUBS'); return false;" href="http://www.springerlink.com/content/g4295k8x56wj20g0/"><span id="translatedtitle">Complementary models of <span class="hlt">tree</span> <span class="hlt">species</span>-soil relationships in old-growth temperate forests</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Cross, Alison; Perakis, Steven S.</p> <p>2011-01-01</p> <p>Ecosystem level studies identify plant soil feed backs as important controls on soil nutrient availability,particularly for nitrogen and phosphorus. Although site and <span class="hlt">species</span> specific studies of <span class="hlt">tree</span> <span class="hlt">species</span> soil relationships are relatively common,comparatively fewer studies consider multiple coexisting speciesin old-growth forests across a range of sites that vary underlying soil fertility. We characterized patterns in forest floor and mineral soil nutrients associated with four common <span class="hlt">tree</span> <span class="hlt">species</span> across eight undisturbed old-growth forests in Oregon, USA, and used two complementary conceptual models to assess <span class="hlt">tree</span> <span class="hlt">species</span> soil relationships. Plant soil feedbacks that could reinforce sitelevel differences in nutrient availability were assessed using the context dependent relationships model, where by relative <span class="hlt">species</span> based differences in each soil nutrient divergedorconvergedas nutrient status changed across sites. <span class="hlt">Tree</span> <span class="hlt">species</span> soil relationships that did not reflect strong feedbacks were evaluated using a site independent relationships model, where by forest floor and surface mineral soil nutrient tools differed consistently by <span class="hlt">tree</span> <span class="hlt">species</span> across sites,without variation in deeper mineral soils. We found that theorganically cycled elements carbon, nitrogen, and phosphorus exhibited context-dependent differences among <span class="hlt">species</span> in both forest floor and mineral soil, and most of ten followed adivergence model,where by <span class="hlt">species</span> differences were greatest at high-nutrient sites. These patterns are consistent with the oryemphasizing biotic control of these elements through plant soil feedback mechanisms. Site independent <span class="hlt">species</span> differences were strongest for pool so if the weather able cations calcium, magnesium, potassium,as well as phosphorus, in mineral soils. Site independent <span class="hlt">species</span> differences in forest floor nutrients we reattributable too nespecies that displayed significant greater forest floor mass accumulation. Our finding confirmed that site-independent and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4407066','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4407066"><span id="translatedtitle">How <span class="hlt">tree</span> <span class="hlt">species</span> fill geographic and ecological space in eastern North America</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ricklefs, Robert E.</p> <p>2015-01-01</p> <p>Background and Aims Ecologists broadly accept that the number of <span class="hlt">species</span> present within a region balances regional processes of immigration and speciation against competitive and other interactions between populations that limit distribution and constrain diversity. Although ecological theory has, for a long time, addressed the premise that ecological space can be filled to ‘capacity’ with <span class="hlt">species</span>, only with the availability of time-calibrated phylogenies has it been possible to test the hypothesis that diversification slows as the number of <span class="hlt">species</span> in a region increases. Focusing on the deciduous <span class="hlt">trees</span> of eastern North America, this study tested predictions from competition theory concerning the distribution and abundance of <span class="hlt">species</span>. Methods Local assemblages of <span class="hlt">trees</span> tabulated in a previous study published in 1950 were analysed. Assemblages were ordinated with respect to <span class="hlt">species</span> composition by non-metric multidimensional scaling (NMS). Distributions of <span class="hlt">trees</span> were analysed by taxonomically nested analysis of variance, discriminant analysis based on NMS scores, and canonical correlation analysis of NMS scores and Bioclim climate variables. Key Results Most of the variance in <span class="hlt">species</span> abundance and distribution was concentrated among closely related (i.e. congeneric) <span class="hlt">species</span>, indicating evolutionary lability. <span class="hlt">Species</span> distribution and abundance were unrelated to the number of close relatives, suggesting that competitive effects are diffuse. Distances between pairs of congeneric <span class="hlt">species</span> in NMS space did not differ significantly from distances between more distantly related <span class="hlt">species</span>, in contrast to the predictions of both competitive habitat partitioning and ecological sorting of <span class="hlt">species</span>. Conclusions Eastern deciduous forests of North America do not appear to be saturated with <span class="hlt">species</span>. The distributions and abundances of individual <span class="hlt">species</span> provide little evidence of being shaped by competition from related (i.e. ecologically similar) <span class="hlt">species</span> and, by inference, that</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014EnMan..53..783S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014EnMan..53..783S&link_type=ABSTRACT"><span id="translatedtitle">The Right <span class="hlt">Tree</span> for the Job? Perceptions of <span class="hlt">Species</span> Suitability for the Provision of Ecosystem Services</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smaill, Simeon J.; Bayne, Karen M.; Coker, Graham W. R.; Paul, Thomas S. H.; Clinton, Peter W.</p> <p>2014-04-01</p> <p>Stakeholders in plantation forestry are increasingly aware of the importance of the ecosystem services and non-market values associated with forests. In New Zealand, there is significant interest in establishing <span class="hlt">species</span> other than Pinus radiata D. Don (the dominant plantation <span class="hlt">species</span>) in the belief that alternative <span class="hlt">species</span> are better suited to deliver these services. Significant risk is associated with this position as there is little objective data to support these views. To identify which <span class="hlt">species</span> were likely to be planted to deliver ecosystem services, a survey was distributed to examine stakeholder perceptions. Stakeholders were asked which of 15 <span class="hlt">tree</span> attributes contributed to the provision of five ecosystem services (amenity value, bioenergy production, carbon capture, the diversity of native habitat, and erosion control/water quality) and to identify which of 22 candidate <span class="hlt">tree</span> <span class="hlt">species</span> possessed those attributes. These data were combined to identify the <span class="hlt">species</span> perceived most suitable for the delivery of each ecosystem service. Sequoia sempervirens (D.Don) Endl. closely matched the stakeholder derived ideotypes associated with all five ecosystem services. Comparisons to data from growth, physiological and ecological studies demonstrated that many of the opinions held by stakeholders were inaccurate, leading to erroneous assumptions regarding the suitability of most candidate <span class="hlt">species</span>. Stakeholder perceptions substantially influence <span class="hlt">tree</span> <span class="hlt">species</span> selection, and plantations established on the basis of inaccurate opinions are unlikely to deliver the desired outcomes. Attitudinal surveys associated with engagement campaigns are essential to improve stakeholder knowledge, advancing the development of fit-for-purpose forest management that provides the required ecosystem services.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25292455','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25292455"><span id="translatedtitle">Stem CO2 efflux in six co-occurring <span class="hlt">tree</span> <span class="hlt">species</span>: underlying factors and ecological implications.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rodríguez-Calcerrada, Jesús; López, Rosana; Salomón, Roberto; Gordaliza, Guillermo G; Valbuena-Carabaña, María; Oleksyn, Jacek; Gil, Luis</p> <p>2015-06-01</p> <p>Stem respiration plays a role in <span class="hlt">species</span> coexistence and forest dynamics. Here we examined the intra- and inter-specific variability of stem CO2 efflux (E) in dominant and suppressed <span class="hlt">trees</span> of six deciduous <span class="hlt">species</span> in a mixed forest stand: Fagus sylvatica L., Quercus petraea [Matt.] Liebl, Quercus pyrenaica Willd., Prunus avium L., Sorbus aucuparia L. and Crataegus monogyna Jacq. We conducted measurements in late autumn. Within <span class="hlt">species</span>, dominants had higher E per unit stem surface area (Es ) mainly because sapwood depth was higher than in suppressed <span class="hlt">trees</span>. Across <span class="hlt">species</span>, however, differences in Es corresponded with differences in the proportion of living parenchyma in sapwood and concentration of non-structural carbohydrates (NSC). Across <span class="hlt">species</span>, Es was strongly and NSC marginally positively related with an index of drought tolerance, suggesting that slow growth of drought-tolerant <span class="hlt">trees</span> is related to higher NSC concentration and Es . We conclude that, during the leafless period, E is indicative of maintenance respiration and is related with some ecological characteristics of the <span class="hlt">species</span>, such as drought resistance; that sapwood depth is the main factor explaining variability in Es within <span class="hlt">species</span>; and that the proportion of NSC in the sapwood is the main factor behind variability in Es among <span class="hlt">species</span>. PMID:25292455</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21362638','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21362638"><span id="translatedtitle">Detecting phylogenetic breakpoints and discordance from genome-wide alignments for <span class="hlt">species</span> <span class="hlt">tree</span> reconstruction.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ané, Cécile</p> <p>2011-01-01</p> <p>With the easy acquisition of sequence data, it is now possible to obtain and align whole genomes across multiple related <span class="hlt">species</span> or populations. In this work, I assess the performance of a statistical method to reconstruct the whole distribution of phylogenetic <span class="hlt">trees</span> along the genome, estimate the proportion of the genome for which a given clade is true, and infer a concordance <span class="hlt">tree</span> that summarizes the dominant vertical inheritance pattern. There are two main issues when dealing with whole-genome alignments, as opposed to multiple genes: the size of the data and the detection of recombination breakpoints. These breakpoints partition the genomic alignment into phylogenetically homogeneous loci, where sites within a given locus all share the same phylogenetic <span class="hlt">tree</span> topology. To delimitate these loci, I describe here a method based on the minimum description length (MDL) principle, implemented with dynamic programming for computational efficiency. Simulations show that combining MDL partitioning with Bayesian concordance analysis provides an efficient and robust way to estimate both the vertical inheritance signal and the horizontal phylogenetic signal. The method performed well both in the presence of incomplete lineage sorting and in the presence of horizontal gene transfer. A high level of systematic bias was found here, highlighting the need for good individual <span class="hlt">tree</span> building methods, which form the basis for more elaborate gene <span class="hlt">tree/species</span> <span class="hlt">tree</span> reconciliation methods. PMID:21362638</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4538783','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4538783"><span id="translatedtitle"><span class="hlt">Tree</span> cover at fine and coarse spatial grains interacts with shade tolerance to shape plant <span class="hlt">species</span> distributions across the Alps</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Nieto-Lugilde, Diego; Lenoir, Jonathan; Abdulhak, Sylvain; Aeschimann, David; Dullinger, Stefan; Gégout, Jean-Claude; Guisan, Antoine; Pauli, Harald; Renaud, Julien; Theurillat, Jean-Paul; Thuiller, Wilfried; Van Es, Jérémie; Vittoz, Pascal; Willner, Wolfgang; Wohlgemuth, Thomas; Zimmermann, Niklaus E.; Svenning, Jens-Christian</p> <p>2015-01-01</p> <p>The role of competition for light among plants has long been recognised at local scales, but its importance for plant <span class="hlt">species</span> distributions at larger spatial scales has generally been ignored. <span class="hlt">Tree</span> cover modifies the local abiotic conditions below the canopy, notably by reducing light availability, and thus, also the performance of <span class="hlt">species</span> that are not adapted to low-light conditions. However, this local effect may propagate to coarser spatial grains, by affecting colonisation probabilities and local extinction risks of herbs and shrubs. To assess the effect of <span class="hlt">tree</span> cover at both the plot- and landscape-grain sizes (approximately 10-m and 1-km), we fit Generalised Linear Models (GLMs) for the plot-level distributions of 960 <span class="hlt">species</span> of herbs and shrubs using 6,935 vegetation plots across the European Alps. We ran four models with different combinations of variables (climate, soil and <span class="hlt">tree</span> cover) at both spatial grains for each <span class="hlt">species</span>. We used partial regressions to evaluate the independent effects of plot- and landscape-grain <span class="hlt">tree</span> cover on plot-level plant communities. Finally, the effects on <span class="hlt">species</span>-specific elevational range limits were assessed by simulating a removal experiment comparing the <span class="hlt">species</span> distributions under high and low <span class="hlt">tree</span> cover. Accounting for <span class="hlt">tree</span> cover improved the model performance, with the probability of the presence of shade-tolerant <span class="hlt">species</span> increasing with increasing <span class="hlt">tree</span> cover, whereas shade-intolerant <span class="hlt">species</span> showed the opposite pattern. The <span class="hlt">tree</span> cover effect occurred consistently at both the plot and landscape spatial grains, albeit most strongly at the former. Importantly, <span class="hlt">tree</span> cover at the two grain sizes had partially independent effects on plot-level plant communities. With high <span class="hlt">tree</span> cover, shade-intolerant <span class="hlt">species</span> exhibited narrower elevational ranges than with low <span class="hlt">tree</span> cover whereas shade-tolerant <span class="hlt">species</span> showed wider elevational ranges at both limits. These findings suggest that forecasts of climate-related range shifts for herb</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23376521','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23376521"><span id="translatedtitle">Forest floor leachate fluxes under six different <span class="hlt">tree</span> <span class="hlt">species</span> on a metal contaminated site.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Van Nevel, Lotte; Mertens, Jan; De Schrijver, An; Baeten, Lander; De Neve, Stefaan; Tack, Filip M G; Meers, Erik; Verheyen, Kris</p> <p>2013-03-01</p> <p><span class="hlt">Trees</span> play an important role in the biogeochemical cycling of metals, although the influence of different <span class="hlt">tree</span> <span class="hlt">species</span> on the mobilization of metals is not yet clear. This study examined effects of six <span class="hlt">tree</span> <span class="hlt">species</span> on fluxes of Cd, Zn, DOC, H(+) and base cations in forest floor leachates on a metal polluted site in Belgium. Forest floor leachates were sampled with zero-tension lysimeters in a 12-year-old post-agricultural forest on a sandy soil. The <span class="hlt">tree</span> <span class="hlt">species</span> included were silver birch (Betula pendula), oak (Quercus robur and Q. petraea), black locust (Robinia pseudoacacia), aspen (Populus tremula), Scots pine (Pinus sylvestris) and Douglas fir (Pseudotsuga menziesii). We show that total Cd fluxes in forest floor leachate under aspen were slightly higher than those in the other <span class="hlt">species</span>' leachates, yet the relative differences between the <span class="hlt">species</span> were considerably smaller when looking at dissolved Cd fluxes. The latter was probably caused by extremely low H(+) amounts leaching from aspen's forest floor. No <span class="hlt">tree</span> <span class="hlt">species</span> effect was found for Zn leachate fluxes. We expected higher metal leachate fluxes under aspen as its leaf litter was significantly contaminated with Cd and Zn. We propose that the low amounts of Cd and Zn leaching under aspen's forest floor were possibly caused by high activity of soil biota, for example burrowing earthworms. Furthermore, our results reveal that Scots pine and oak were characterized by high H(+) and DOC fluxes as well as low base cation fluxes in their forest floor leachates, implying that those <span class="hlt">species</span> might enhance metal mobilization in the soil profile and thus bear a potential risk for belowground metal dispersion. PMID:23376521</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27220216','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27220216"><span id="translatedtitle">Interspecific variation in growth responses to climate and competition of five eastern <span class="hlt">tree</span> <span class="hlt">species</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rollinson, Christine R; Kaye, Margot W; Canham, Charles D</p> <p>2016-04-01</p> <p>Climate and competition are often presented from two opposing views of the dominant driver of individual <span class="hlt">tree</span> growth and <span class="hlt">species</span> distribution in temperate forests, such as those in the eastern United States. Previous studies have provided abundant evidence indicating that both factors influence <span class="hlt">tree</span> growth, and we argue that these effects are not independent of one another and rather that interactions between climate, competition, and size best describe <span class="hlt">tree</span> growth. To illustrate this point, we describe the growth responses of five common eastern <span class="hlt">tree</span> <span class="hlt">species</span> to interacting effects of temperature, precipitation, competition, and individual size using maximum likelihood estimation. Models that explicitly include interactions among these four factors explained over half of the variance in annual growth for four out of five <span class="hlt">species</span> using annual climate. Expanding temperature and precipitation analyses to include seasonal interactions resulted in slightly improved models with a mean R2 of 0.61 (SD 0.10). Growth responses to individual factors as well their interactions varied greatly among <span class="hlt">species</span>. For example, growth sensitivity to temperature for Quercus rubra increased with maximum annual precipitation, but other <span class="hlt">species</span> showed no change in sensitivity or slightly reduced annual growth. Our results also indicate that three-way interactions among individual stem size, competition, and temperature may determine which of the five co-occurring <span class="hlt">species</span> in our study could have the highest growth rate in a given year. Continued consideration and quantification of interactions among climate, competition, and individual-based characteristics are likely to increase understanding of key biological processes such as <span class="hlt">tree</span> growth. Greater parameterization of interactions between traditionally segregated factors such as climate and competition may also help build a framework to reconcile drivers of individual-based processes such as growth with larger-scale patterns of <span class="hlt">species</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.B43C0563C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.B43C0563C"><span id="translatedtitle">A Section-based Method For <span class="hlt">Tree</span> <span class="hlt">Species</span> Classification Using Airborne LiDAR Discrete Points In Urban Areas</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chunjing, Y. C.; Hui, T.; Zhongjie, R.; Guikai, B.</p> <p>2015-12-01</p> <p>As a new approach to forest inventory utilizing, LiDAR remote sensing has become an important research issue in the past. Lidar researches initially concentrate on the investigation for mapping forests at the <span class="hlt">tree</span> level and identifying important structural parameters, such as <span class="hlt">tree</span> height, crown size, crown base height, individual <span class="hlt">tree</span> <span class="hlt">species</span>, and stem volume etc. But for the virtual city visualization and mapping, the traditional methods of <span class="hlt">tree</span> classification can't satisfy the more complex conditions. Recently, the advanced LiDAR technology has generated new full waveform scanners that provide a higher point density and additional information about the reflecting characteristics of <span class="hlt">trees</span>. Subsequently, it was demonstrated that it is feasible to detect individual overstorey <span class="hlt">trees</span> in forests and classify <span class="hlt">species</span>. But the important issues like the calibration and the decomposition of full waveform data with a series of Gaussian functions usually take a lot of works. What's more, the detection and classification of vegetation results relay much on the prior outcomes. From all above, the section-based method for <span class="hlt">tree</span> <span class="hlt">species</span> classification using small footprint and high sampling density lidar data is proposed in this paper, which can overcome the <span class="hlt">tree</span> <span class="hlt">species</span> classification issues in urban areas. More specific objectives are to: (1)use local maximum height decision and four direction sections certification methods to get the precise locations of the <span class="hlt">trees</span>;(2) develop new lidar-derived features processing techniques for characterizing the section structure of individual <span class="hlt">tree</span> crowns;(3) investigate several techniques for filtering and analyzing vertical profiles of individual <span class="hlt">trees</span> to classify the <span class="hlt">trees</span>, and using the expert decision skills based on percentile analysis;(4) assess the accuracy of estimating <span class="hlt">tree</span> <span class="hlt">species</span> for each <span class="hlt">tree</span>, and (5) investigate which type of lidar data, point frequency or intensity, provides the most accurate estimate of <span class="hlt">tree</span> <span class="hlt">species</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26828175','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26828175"><span id="translatedtitle"><span class="hlt">Tree</span> <span class="hlt">Species</span> Suitability to Bioswales and Impact on the Urban Water Budget.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Scharenbroch, Bryant C; Morgenroth, Justin; Maule, Brian</p> <p>2016-01-01</p> <p>Water movement between soil and the atmosphere is restricted by hardscapes in the urban environment. Some green infrastructure is intended to increase infiltration and storage of water, thus decreasing runoff and discharge of urban stormwater. Bioswales are a critical component of a water-sensitive urban design (or a low-impact urban design), and incorporation of <span class="hlt">trees</span> into these green infrastructural components is believed to be a novel way to return stored water to the atmosphere via transpiration. This research was conducted in The Morton Arboretum's main parking lot, which is one of the first and largest green infrastructure installations in the midwestern United States. The parking lot is constructed of permeable pavers and <span class="hlt">tree</span> bioswales. <span class="hlt">Trees</span> in bioswales were evaluated for growth and condition and for their effects on water cycling via transpiration. Our data indicate that <span class="hlt">trees</span> in bioswales accounted for 46 to 72% of total water outputs via transpiration, thereby reducing runoff and discharge from the parking lot. By evaluating the stomatal conductance, diameter growth, and condition of a variety of <span class="hlt">tree</span> <span class="hlt">species</span> in these bioswales, we found that not all <span class="hlt">species</span> are equally suited for bioswales and that not all are equivalent in their transpiration and growth rates, thereby contributing differentially to the functional capacity of bioswales. We conclude that <span class="hlt">species</span> with high stomatal conductance and large mature form are likely to contribute best to bioswale function. PMID:26828175</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013EnMan..51..524M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013EnMan..51..524M&link_type=ABSTRACT"><span id="translatedtitle">Certified and Uncertified Logging Concessions Compared in Gabon: Changes in Stand Structure, <span class="hlt">Tree</span> <span class="hlt">Species</span>, and Biomass</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Medjibe, V. P.; Putz, Francis E.; Romero, Claudia</p> <p>2013-03-01</p> <p>Forest management certification is assumed to promote sustainable forest management, but there is little field-based evidence to support this claim. To help fill this gap, we compared a Forest Stewardship Council (FSC)-certified with an adjacent uncertified, conventionally logged concession (CL) in Gabon on the basis of logging damage, above-ground biomass (AGB), and <span class="hlt">tree</span> <span class="hlt">species</span> diversity and composition. Before logging, we marked, mapped, and measured all <span class="hlt">trees</span> >10 cm dbh in 20 and twelve 1-ha permanent plots in the FSC and CL areas, respectively. Soil and <span class="hlt">tree</span> damage due to felling, skidding, and road-related activities was then assessed 2-3 months after the 508 ha FSC study area and the 200 ha CL study area were selectively logged at respective intensities of 5.7 m3/ha (0.39 <span class="hlt">trees</span>/ha) and 11.4 m3/ha (0.76 <span class="hlt">trees</span>/ha). For each <span class="hlt">tree</span> felled, averages of 9.1 and 20.9 other <span class="hlt">trees</span> were damaged in the FSC and CL plots, respectively; when expressed as the impacts per timber volume extracted, the values did not differ between the two treatments. Skid trails covered 2.9 % more of the CL surface, but skid trail length per unit timber volume extracted was not greater. Logging roads were wider in the CL than FSC site and disturbed 4.7 % more of the surface. Overall, logging caused declines in AGB of 7.1 and 13.4 % at the FSC and CL sites, respectively. Changes in <span class="hlt">tree</span> <span class="hlt">species</span> composition were small but greater for the CL site. Based on these findings and in light of the pseudoreplicated study design with less-than perfect counterfactual, we cautiously conclude that certification yields environmental benefits even after accounting for differences in logging intensities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23277438','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23277438"><span id="translatedtitle">Certified and uncertified logging concessions compared in Gabon: changes in stand structure, <span class="hlt">tree</span> <span class="hlt">species</span>, and biomass.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Medjibe, V P; Putz, Francis E; Romero, Claudia</p> <p>2013-03-01</p> <p>Forest management certification is assumed to promote sustainable forest management, but there is little field-based evidence to support this claim. To help fill this gap, we compared a Forest Stewardship Council (FSC)-certified with an adjacent uncertified, conventionally logged concession (CL) in Gabon on the basis of logging damage, above-ground biomass (AGB), and <span class="hlt">tree</span> <span class="hlt">species</span> diversity and composition. Before logging, we marked, mapped, and measured all <span class="hlt">trees</span> >10 cm dbh in 20 and twelve 1-ha permanent plots in the FSC and CL areas, respectively. Soil and <span class="hlt">tree</span> damage due to felling, skidding, and road-related activities was then assessed 2-3 months after the 508 ha FSC study area and the 200 ha CL study area were selectively logged at respective intensities of 5.7 m(3)/ha (0.39 <span class="hlt">trees</span>/ha) and 11.4 m(3)/ha (0.76 <span class="hlt">trees</span>/ha). For each <span class="hlt">tree</span> felled, averages of 9.1 and 20.9 other <span class="hlt">trees</span> were damaged in the FSC and CL plots, respectively; when expressed as the impacts per timber volume extracted, the values did not differ between the two treatments. Skid trails covered 2.9 % more of the CL surface, but skid trail length per unit timber volume extracted was not greater. Logging roads were wider in the CL than FSC site and disturbed 4.7 % more of the surface. Overall, logging caused declines in AGB of 7.1 and 13.4 % at the FSC and CL sites, respectively. Changes in <span class="hlt">tree</span> <span class="hlt">species</span> composition were small but greater for the CL site. Based on these findings and in light of the pseudoreplicated study design with less-than perfect counterfactual, we cautiously conclude that certification yields environmental benefits even after accounting for differences in logging intensities. PMID:23277438</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27490180','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27490180"><span id="translatedtitle">Direct vs. Microclimate-Driven Effects of <span class="hlt">Tree</span> <span class="hlt">Species</span> Diversity on Litter Decomposition in Young Subtropical Forest Stands.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Seidelmann, Katrin N; Scherer-Lorenzen, Michael; Niklaus, Pascal A</p> <p>2016-01-01</p> <p>Effects of <span class="hlt">tree</span> <span class="hlt">species</span> diversity on decomposition can operate via a multitude of mechanism, including alterations of microclimate by the forest canopy. Studying such effects in natural settings is complicated by the fact that topography also affects microclimate and thus decomposition, so that effects of diversity are more difficult to isolate. Here, we quantified decomposition rates of standard litter in young subtropical forest stands, separating effects of canopy <span class="hlt">tree</span> <span class="hlt">species</span> richness and topography, and quantifying their direct and micro-climate-mediated components. Our litterbag study was carried out at two experimental sites of a biodiversity-ecosystem functioning field experiment in south-east China (BEF-China). The field sites display strong topographical heterogeneity and were planted with <span class="hlt">tree</span> communities ranging from monocultures to mixtures of 24 native subtropical <span class="hlt">tree</span> <span class="hlt">species</span>. Litter bags filled with senescent leaves of three native <span class="hlt">tree</span> <span class="hlt">species</span> were placed from Nov. 2011 to Oct. 2012 on 134 plots along the <span class="hlt">tree</span> <span class="hlt">species</span> diversity gradient. Topographic features were measured for all and microclimate in a subset of plots. Stand <span class="hlt">species</span> richness, topography and microclimate explained important fractions of the variations in litter decomposition rates, with diversity and topographic effects in part mediated by microclimatic changes. <span class="hlt">Tree</span> stands were 2-3 years old, but nevertheless <span class="hlt">tree</span> <span class="hlt">species</span> diversity explained more variation (54.3%) in decomposition than topography (7.7%). <span class="hlt">Tree</span> <span class="hlt">species</span> richness slowed litter decomposition, an effect that slightly depended on litter <span class="hlt">species</span> identity. A large part of the variance in decomposition was explained by <span class="hlt">tree</span> <span class="hlt">species</span> composition, with the presence of three <span class="hlt">tree</span> <span class="hlt">species</span> playing a significant role. Microclimate explained 31.4% of the variance in decomposition, and was related to lower soil moisture. Within this microclimate effect, <span class="hlt">species</span> diversity (without composition) explained 8.9% and topography 34.4% of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4973968','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4973968"><span id="translatedtitle">Direct vs. Microclimate-Driven Effects of <span class="hlt">Tree</span> <span class="hlt">Species</span> Diversity on Litter Decomposition in Young Subtropical Forest Stands</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Seidelmann, Katrin N.; Scherer-Lorenzen, Michael; Niklaus, Pascal A.</p> <p>2016-01-01</p> <p>Effects of <span class="hlt">tree</span> <span class="hlt">species</span> diversity on decomposition can operate via a multitude of mechanism, including alterations of microclimate by the forest canopy. Studying such effects in natural settings is complicated by the fact that topography also affects microclimate and thus decomposition, so that effects of diversity are more difficult to isolate. Here, we quantified decomposition rates of standard litter in young subtropical forest stands, separating effects of canopy <span class="hlt">tree</span> <span class="hlt">species</span> richness and topography, and quantifying their direct and micro-climate-mediated components. Our litterbag study was carried out at two experimental sites of a biodiversity-ecosystem functioning field experiment in south-east China (BEF-China). The field sites display strong topographical heterogeneity and were planted with <span class="hlt">tree</span> communities ranging from monocultures to mixtures of 24 native subtropical <span class="hlt">tree</span> <span class="hlt">species</span>. Litter bags filled with senescent leaves of three native <span class="hlt">tree</span> <span class="hlt">species</span> were placed from Nov. 2011 to Oct. 2012 on 134 plots along the <span class="hlt">tree</span> <span class="hlt">species</span> diversity gradient. Topographic features were measured for all and microclimate in a subset of plots. Stand <span class="hlt">species</span> richness, topography and microclimate explained important fractions of the variations in litter decomposition rates, with diversity and topographic effects in part mediated by microclimatic changes. <span class="hlt">Tree</span> stands were 2–3 years old, but nevertheless <span class="hlt">tree</span> <span class="hlt">species</span> diversity explained more variation (54.3%) in decomposition than topography (7.7%). <span class="hlt">Tree</span> <span class="hlt">species</span> richness slowed litter decomposition, an effect that slightly depended on litter <span class="hlt">species</span> identity. A large part of the variance in decomposition was explained by <span class="hlt">tree</span> <span class="hlt">species</span> composition, with the presence of three <span class="hlt">tree</span> <span class="hlt">species</span> playing a significant role. Microclimate explained 31.4% of the variance in decomposition, and was related to lower soil moisture. Within this microclimate effect, <span class="hlt">species</span> diversity (without composition) explained 8.9% and topography 34.4% of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4134238','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4134238"><span id="translatedtitle">Patterns of <span class="hlt">Tree</span> <span class="hlt">Species</span> Diversity in Relation to Climatic Factors on the Sierra Madre Occidental, Mexico</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Silva-Flores, Ramón; Pérez-Verdín, Gustavo; Wehenkel, Christian</p> <p>2014-01-01</p> <p>Biological diversity can be defined as variability among living organisms from all sources, including terrestrial organisms, marine and other aquatic ecosystems, and the ecological complexes which they are part of. This includes diversity within <span class="hlt">species</span>, between <span class="hlt">species</span>, and of ecosystems. Numerous diversity indices combine richness and evenness in a single expression, and several climate-based explanations have been proposed to explain broad-scale diversity patterns. However, climate-based water-energy dynamics appears to be an essential factor that determines patterns of diversity. The Mexican Sierra Madre Occidental occupies an area of about 29 million hectares and is located between the Neotropical and Holarctic ecozones. It shelters a high diversity of flora, including 24 different <span class="hlt">species</span> of Pinus (ca. 22% on the whole), 54 <span class="hlt">species</span> of Quercus (ca. 9–14%), 7 <span class="hlt">species</span> of Arbutus (ca. 50%) and many other <span class="hlt">trees</span> <span class="hlt">species</span>. The objectives of this study were to model how <span class="hlt">tree</span> <span class="hlt">species</span> diversity is related to climatic and geographic factors and stand density and to test the Metabolic Theory, Productivity-Diversity Hypothesis, Physiological Tolerance Hypothesis, Mid-Domain Effect, and the Water-Energy Dynamic Theory on the Sierra Madre Occidental, Durango. The results supported the Productivity-Diversity Hypothesis, Physiological Tolerance Hypothesis and Water-Energy Dynamic Theory, but not the Mid-Domain Effect or Metabolic Theory. The annual aridity index was the variable most closely related to the diversity indices analyzed. Contemporary climate was found to have moderate to strong effects on the minimum, median and maximum <span class="hlt">tree</span> <span class="hlt">species</span> diversity. Because water-energy dynamics provided a satisfactory explanation for the patterns of minimum, median and maximum diversity, an understanding of this factor is critical to future biodiversity research. Quantile regression of the data showed that the three diversity parameters of <span class="hlt">tree</span> <span class="hlt">species</span> are generally higher in cold</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25127455','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25127455"><span id="translatedtitle">Patterns of <span class="hlt">tree</span> <span class="hlt">species</span> diversity in relation to climatic factors on the Sierra Madre Occidental, Mexico.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Silva-Flores, Ramón; Pérez-Verdín, Gustavo; Wehenkel, Christian</p> <p>2014-01-01</p> <p>Biological diversity can be defined as variability among living organisms from all sources, including terrestrial organisms, marine and other aquatic ecosystems, and the ecological complexes which they are part of. This includes diversity within <span class="hlt">species</span>, between <span class="hlt">species</span>, and of ecosystems. Numerous diversity indices combine richness and evenness in a single expression, and several climate-based explanations have been proposed to explain broad-scale diversity patterns. However, climate-based water-energy dynamics appears to be an essential factor that determines patterns of diversity. The Mexican Sierra Madre Occidental occupies an area of about 29 million hectares and is located between the Neotropical and Holarctic ecozones. It shelters a high diversity of flora, including 24 different <span class="hlt">species</span> of Pinus (ca. 22% on the whole), 54 <span class="hlt">species</span> of Quercus (ca. 9-14%), 7 <span class="hlt">species</span> of Arbutus (ca. 50%) and many other <span class="hlt">trees</span> <span class="hlt">species</span>. The objectives of this study were to model how <span class="hlt">tree</span> <span class="hlt">species</span> diversity is related to climatic and geographic factors and stand density and to test the Metabolic Theory, Productivity-Diversity Hypothesis, Physiological Tolerance Hypothesis, Mid-Domain Effect, and the Water-Energy Dynamic Theory on the Sierra Madre Occidental, Durango. The results supported the Productivity-Diversity Hypothesis, Physiological Tolerance Hypothesis and Water-Energy Dynamic Theory, but not the Mid-Domain Effect or Metabolic Theory. The annual aridity index was the variable most closely related to the diversity indices analyzed. Contemporary climate was found to have moderate to strong effects on the minimum, median and maximum <span class="hlt">tree</span> <span class="hlt">species</span> diversity. Because water-energy dynamics provided a satisfactory explanation for the patterns of minimum, median and maximum diversity, an understanding of this factor is critical to future biodiversity research. Quantile regression of the data showed that the three diversity parameters of <span class="hlt">tree</span> <span class="hlt">species</span> are generally higher in cold</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21691855','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21691855"><span id="translatedtitle"><span class="hlt">Tree</span> <span class="hlt">species</span> identity and interactions with neighbors determine nutrient leaching in model tropical forests.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ewel, John J; Bigelow, Seth W</p> <p>2011-12-01</p> <p>An ecosystem containing a mixture of <span class="hlt">species</span> that differ in phenology, morphology, and physiology might be expected to resist leaching of soil nutrients to a greater extent than one composed of a single <span class="hlt">species</span>. We tested the effects of <span class="hlt">species</span> identity and plant-life-form richness on nutrient leaching at a lowland tropical site where deep infiltration averages >2 m year(-1). Three indigenous <span class="hlt">tree</span> <span class="hlt">species</span> with contrasting leafing phenologies (evergreen, dry-season deciduous, and wet-season deciduous) were grown in monoculture and together with two other life-forms with which they commonly occur in tropical forests: a palm and a giant, perennial herb. To calculate nutrient leaching over an 11-year period, concentrations of nutrients in soil water were multiplied by drainage rates estimated from a water balance. The effect of plant-life-form richness on retention differed according to <span class="hlt">tree</span> <span class="hlt">species</span> identity and nutrient. Nitrate retention was greater in polycultures of the dry-season deciduous <span class="hlt">tree</span> <span class="hlt">species</span> (mean of 7.4 kg ha(-1) year(-1) of NO(3)-N lost compared to 12.7 in monoculture), and calcium and magnesium retention were greater in polycultures of the evergreen and wet-season deciduous <span class="hlt">tree</span> <span class="hlt">species</span>. Complementary use of light led to intensification of soil exploitation by roots, the main agent responsible for enhanced nutrient retention in some polycultures. Other mechanisms included differences in nutrient demand among <span class="hlt">species</span>, and avoidance of catastrophic failure due to episodic weather events or pest outbreaks. Even unrealistically simple multi-life-form mimics of tropical forest can safeguard a site's nutrient capital if careful attention is paid to <span class="hlt">species</span>' characteristics and temporal changes in interspecific interactions. PMID:21691855</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4206468','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4206468"><span id="translatedtitle">Data Concatenation, Bayesian Concordance and Coalescent-Based Analyses of the <span class="hlt">Species</span> <span class="hlt">Tree</span> for the Rapid Radiation of Triturus Newts</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wielstra, Ben; Arntzen, Jan W.; van der Gaag, Kristiaan J.; Pabijan, Maciej; Babik, Wieslaw</p> <p>2014-01-01</p> <p>The phylogenetic relationships for rapid <span class="hlt">species</span> radiations are difficult to disentangle. Here we study one such case, namely the genus Triturus, which is composed of the marbled and crested newts. We analyze data for 38 genetic markers, positioned in 3-prime untranslated regions of protein-coding genes, obtained with 454 sequencing. Our dataset includes twenty Triturus newts and represents all nine <span class="hlt">species</span>. Bayesian analysis of population structure allocates all individuals to their respective <span class="hlt">species</span>. The branching patterns obtained by data concatenation, Bayesian concordance analysis and coalescent-based estimations of the <span class="hlt">species</span> <span class="hlt">tree</span> differ from one another. The data concatenation based <span class="hlt">species</span> <span class="hlt">tree</span> shows high branch support but branching order is considerably affected by allele choice in the case of heterozygotes in the concatenation process. Bayesian concordance analysis expresses the conflict between individual gene <span class="hlt">trees</span> for part of the Triturus <span class="hlt">species</span> <span class="hlt">tree</span> as low concordance factors. The coalescent-based <span class="hlt">species</span> <span class="hlt">tree</span> is relatively similar to a previously published <span class="hlt">species</span> <span class="hlt">tree</span> based upon morphology and full mtDNA and any conflicting internal branches are not highly supported. Our findings reflect high gene <span class="hlt">tree</span> discordance due to incomplete lineage sorting (possibly aggravated by hybridization) in combination with low information content of the markers employed (as can be expected for relatively recent <span class="hlt">species</span> radiations). This case study highlights the complexity of resolving rapid radiations and we acknowledge that to convincingly resolve the Triturus <span class="hlt">species</span> <span class="hlt">tree</span> even more genes will have to be consulted. PMID:25337997</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1712942H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1712942H"><span id="translatedtitle"><span class="hlt">Tree</span> <span class="hlt">species</span> specific soil moisture patterns and dynamics through the seasons</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Heidbüchel, Ingo; Dreibrodt, Janek; Simard, Sonia; Güntner, Andreas; Blume, Theresa</p> <p>2015-04-01</p> <p>Soil moisture patterns in the landscape are largely controlled by soil types (pore size distributions) and landscape position. But how strong is the influence of vegetation on patterns within a single soil type? While we would envision a clear difference in soil moisture patterns and responses between for example bare soil, a pasture and a forest, our conceptual images start to become less clear when we move on to different forest stands. Do different <span class="hlt">tree</span> <span class="hlt">species</span> cause different moisture patterns to emerge? Could it be possible to identify the dominant <span class="hlt">tree</span> <span class="hlt">species</span> of a site by classifying its soil moisture pattern? To investigate this question we analyzed data from 15 sensor clusters in the lowlands of north-eastern Germany (within the TERENO observatory) which were instrumented with soil moisture sensors (5 profiles per site), tensiometers, sap flow sensors, throughfall and stemflow gages. Data has been collected at these sites since May 2014. While the summer data has already been analyzed, the analysis of the winter data and thus the possible seasonal shifts in patterns will be carried out in the coming months. Throughout the last summer we found different dynamics of soil moisture patterns under pine <span class="hlt">trees</span> compared to beech <span class="hlt">trees</span>. While the soils under beech <span class="hlt">trees</span> were more often relatively wet and more often relatively dry, the soils under pine <span class="hlt">trees</span> showed less variability and more often average soil moisture. These differences are most likely due to differences in both throughfall patterns as well as root water uptake. Further analysis includes the use of throughfall and stemflow data as well as stable water isotope samples that were taken at different depths in the soil, in the groundwater and from the sapwood. The manifestation of <span class="hlt">tree</span> <span class="hlt">species</span> differences in soil moisture patterns and dynamics is likely to have implications for groundwater recharge, transit times and hydrologic partitioning.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70031880','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70031880"><span id="translatedtitle">Influences of calcium availability and <span class="hlt">tree</span> <span class="hlt">species</span> on Ca isotope fractionation in soil and vegetation</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Page, B.D.; Bullen, T.D.; Mitchell, M.J.</p> <p>2008-01-01</p> <p>The calcium (Ca) isotope system is potentially of great use for understanding biogeochemical processes at multiple scales in forest ecosystems, yet remains largely unexplored for this purpose. In order to further our understanding of Ca behavior in forests, we examined two nearly adjacent hardwood-dominated catchments with differing soil Ca concentrations, developed from crystalline bedrock, to determine the variability of 44Ca/ 40Ca ratios (expressed as ??44Ca) within soil and vegetation pools. For both sugar maple and American beech, the Ca isotope compositions of the measured roots and calculated bulk <span class="hlt">trees</span> were considerably lighter than those of soil pools at these sites, suggesting that the <span class="hlt">trees</span> were able to preferentially take up light Ca at the root-soil interface. The Ca isotope compositions of three of four root samples were among the lightest values yet reported for terrestrial materials (??44Ca ???-3.95???). Our results further indicate that Ca isotopes were fractionated along the transpiration streams of both <span class="hlt">tree</span> <span class="hlt">species</span> with roots having the least ??44Ca values and leaf litter the greatest. An approximately 2??? difference in ??44Ca values between roots and leaf litter of both <span class="hlt">tree</span> <span class="hlt">species</span> suggests a persistent fractionation mechanism along the transpiration stream, likely related to Ca binding in wood tissue coupled with internal ion exchange. Finally, our data indicate that differing <span class="hlt">tree</span> <span class="hlt">species</span> demand for Ca and soil Ca concentrations together may influence Ca isotope distribution within the <span class="hlt">trees</span>. Inter-catchment differences in Ca isotope distributions in soils and <span class="hlt">trees</span> were minor, indicating that the results of our study may have broad transferability to studies of forest ecosystems in catchments developed on crystalline substrates elsewhere. ?? 2008 Springer Science+Business Media B.V.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/17204076','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/17204076"><span id="translatedtitle">Large variation in whole-plant water-use efficiency among tropical <span class="hlt">tree</span> <span class="hlt">species</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cernusak, Lucas A; Aranda, Jorge; Marshall, John D; Winter, Klaus</p> <p>2007-01-01</p> <p>It is well known that whole-plant water-use efficiency (transpiration efficiency of carbon gain, TE(C)) varies among plant <span class="hlt">species</span> with different photosynthetic pathways. However, less is known of such variation among <span class="hlt">tree</span> <span class="hlt">species</span> within the C(3) group. Here we measured the TE(C) of seven C(3) tropical <span class="hlt">tree</span> <span class="hlt">species</span>. Isotopic analyses (delta(13)C, delta(18)O, and delta(15)N) and elemental analyses (carbon and nitrogen) were undertaken to provide insight into sources of variation in TE(C). Plants were grown over several months in approx. 80% full sunlight in individual 38-l containers in the Republic of Panama. Soil moisture content was nonlimiting. Significant variation was observed in TE(C) among the C(3) <span class="hlt">tree</span> <span class="hlt">species</span>. Values ranged from 1.6 mmol C mol(-1) H(2)O for teak (Tectona grandis) to 4.0 mmol C mol(-1) H(2)O for a legume, Platymiscium pinnatum. Variation in TE(C) was correlated with both leaf N concentration, a proxy for photosynthetic capacity, and oxygen-isotope enrichment, a proxy for stomatal conductance. The TE(C) varied with C-isotope discrimination within <span class="hlt">species</span>, but the relationship broke down among <span class="hlt">species</span>, reflecting the existence of <span class="hlt">species</span>-specific offsets. PMID:17204076</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.B23A0359M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.B23A0359M"><span id="translatedtitle">Leaf gas exchange traits of domestic and exotic <span class="hlt">tree</span> <span class="hlt">species</span> in Cambodia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Miyazawa, Y.; Tateishi, M.; Kumagai, T.; Otsuki, K.</p> <p>2009-12-01</p> <p>In forests under the management by community villagers, exotic <span class="hlt">tree</span> <span class="hlt">species</span> with rapid growth rate are introduced in wide range of Cambodia. To evaluate the influence of the introduction on the forest gas exchange and water budget, we investigated the leaf gas exchange traits of two domestic (Dipterocarpus obtusifolius and Shorea roxburghii) and exotic <span class="hlt">tree</span> <span class="hlt">species</span> (Acasia auriculiformis and Eucalyptus camadilansis). We sampled shoots of each <span class="hlt">species</span> and measured the leaf gas exchange traits (photosynthetic rates under different CO2 concentrations, transpiration rate and stomatal conductance) (6 leaves x 3 <span class="hlt">trees</span> x 4 <span class="hlt">species</span>). We carried out this measurement at 2 months intervals for a year from the beginning of rainy season and compared the obtained traits among <span class="hlt">species</span>. Light saturated rate of net photosynthesis was higher in E. camadilansis but did not differ among other <span class="hlt">species</span> both in rainy and dry seasons. Seasonal patter in photosynthetic traits was not obvious. Each <span class="hlt">species</span> changed stomatal conductance in response to changes in environmental conditions. The response was more sensitive than reported values. In this presentation, we show details about the basic information about the leaf-level gas exchange traits, which are required to run soil- vegetation - atmosphere transfer model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010004211','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010004211"><span id="translatedtitle">BOREAS TE-4 Gas Exchange Data from Boreal <span class="hlt">Tree</span> <span class="hlt">Species</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hall, Forrest G. (Editor); Curd, Shelaine (Editor); Collatz, G. James; Berry, Joseph A.; Gamon, John; Fredeen, Art; Fu, Wei</p> <p>2000-01-01</p> <p>The BOREAS TE-4 team collected steady-state gas exchange and reflectance data from several <span class="hlt">species</span> in the BOREAS SSA during 1994 and in the NSA during 1996. Measurements of light, CO2, temperature, and humidity response curves were made by the BOREAS TE-4 team during the summers of 1994 and 1996 using intact attached leaves of boreal forest <span class="hlt">species</span> located in the BOREAS SSA and NSA. These measurements were conducted to calibrate models used to predict photosynthesis, stomatal conductance, and leaf respiration. The 1994 and 1996 data can be used to construct plots of response functions or for parameterizing models. Parameter values are suitable for application in SiB2 (Sellers et al., 1996) or the leaf model of Collatz et al. (1991), and programs can be obtained from the investigators. The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3892915','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3892915"><span id="translatedtitle">Eco-physiological adaptation of dominant <span class="hlt">tree</span> <span class="hlt">species</span> at two contrasting karst habitats in southwestern China</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wu, Qian; Yan, Hui; Xu, Xinwu</p> <p>2013-01-01</p> <p>The purpose of this study was to investigate the eco-physiological adaptation of indigenous woody <span class="hlt">species</span> to their habitats in karst areas of southwestern China. Two contrasting forest habitats were studied: a degraded habitat in Daxiagu and a well-developed habitat in Tianlongshan, and the eco-physiological characteristics of the <span class="hlt">trees</span> were measured for three growth seasons. Photosynthetic rate (Pn), stomatal conductance (gs), and transpiration rate (Tr) of the <span class="hlt">tree</span> <span class="hlt">species</span> in Daxiagu were 2-3 times higher than those in Tianlongshan under ambient conditions. However, this habitat effect was not significant when measurements were taken under controlled conditions. Under controlled conditions, Pn, gs, and Tr of the deciduous <span class="hlt">species</span> were markedly higher than those for the evergreen <span class="hlt">species</span>. Habitat had no significant effect on water use efficiency (WUE) or photochemical characteristics of PSII. The stomatal sensitivity of woody <span class="hlt">species</span> in the degraded habitat was much higher than that in the well-developed habitat. Similarly, the leaf total nitrogen (N) and phosphorus (P) contents expressed on the basis of either dry mass or leaf area were also much higher in Daxiagu than they were in Tianlongshan. The mass-based leaf total N content of deciduous <span class="hlt">species</span> was much higher than that of evergreen <span class="hlt">species</span>, while leaf area-based total N and P contents of evergreens were significantly higher than those of deciduous <span class="hlt">species</span>. The photosynthetic nitrogen- and phosphorus-use efficiencies (PNUE and PPUE) of deciduous <span class="hlt">species</span> were much higher than those of evergreens. Further, the PPUE of the woody <span class="hlt">species</span> in Tianlongshan was much higher than that  of the woody <span class="hlt">species</span> in Daxiagu. The results from three growth seasons imply that the <span class="hlt">tree</span> <span class="hlt">species</span> were able to adapt well to their growth habitats. Furthermore, it seems that so-called “temporary drought stress” may not occur, or may not be severe for most woody plants in karst areas of southwestern China. PMID:24555059</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3586649','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3586649"><span id="translatedtitle">Epigenetic regulation of adaptive responses of forest <span class="hlt">tree</span> <span class="hlt">species</span> to the environment</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Bräutigam, Katharina; Vining, Kelly J; Lafon-Placette, Clément; Fossdal, Carl G; Mirouze, Marie; Marcos, José Gutiérrez; Fluch, Silvia; Fraga, Mario Fernández; Guevara, M Ángeles; Abarca, Dolores; Johnsen, Øystein; Maury, Stéphane; Strauss, Steven H; Campbell, Malcolm M; Rohde, Antje; Díaz-Sala, Carmen; Cervera, María-Teresa</p> <p>2013-01-01</p> <p>Epigenetic variation is likely to contribute to the phenotypic plasticity and adaptative capacity of plant <span class="hlt">species</span>, and may be especially important for long-lived organisms with complex life cycles, including forest <span class="hlt">trees</span>. Diverse environmental stresses and hybridization/polyploidization events can create reversible heritable epigenetic marks that can be transmitted to subsequent generations as a form of molecular “memory”. Epigenetic changes might also contribute to the ability of plants to colonize or persist in variable environments. In this review, we provide an overview of recent data on epigenetic mechanisms involved in developmental processes and responses to environmental cues in plant, with a focus on forest <span class="hlt">tree</span> <span class="hlt">species</span>. We consider the possible role of forest <span class="hlt">tree</span> epigenetics as a new source of adaptive traits in plant breeding, biotechnology, and ecosystem conservation under rapid climate change. PMID:23467802</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25775797','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25775797"><span id="translatedtitle">[Effects of <span class="hlt">tree</span> <span class="hlt">species</span> on polysaccharides content of epiphytic Dendrobium officinale].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Guo, Ying-Ying; Zhu, Yan; Si, Jin-Ping; Liu, Jing-Jing; Wu, Cheng-Yong; Li, Hui</p> <p>2014-11-01</p> <p>To reveals the effects of <span class="hlt">tree</span> <span class="hlt">species</span> on polysaccharides content of epiphytic Dendrobium officinale. The polysaccharides content of D. officinale attached to living tress in wild or stumps in bionic-facility was determined by phenol-sulfuric acid method. There were extremely significant differences of polysaccharides content of D. officinale attached to different <span class="hlt">tree</span> <span class="hlt">species</span>, but the differences had no relationship with the form and nutrition of barks. The polysaccharides content of D. officinale mainly affected by the light intensity of environment, so reasonable illumination favored the accumulation of polysaccharides. Various polysaccharides content of D. officinal from different attached <span class="hlt">trees</span> is due to the difference of light regulation, but not the form and nutrition of barks. PMID:25775797</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFM.B51B0028L&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFM.B51B0028L&link_type=ABSTRACT"><span id="translatedtitle">Dynamics of <span class="hlt">Tree</span> <span class="hlt">Species</span> Composition in Temperate Mountains of South Korea over Fourteen Years using 880 Permanent Plots</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, B.; Kim, H. S.; Park, J.; Moon, M.; Cho, S.; Ryu, D.; Wynn, K. Z.; Park, J.</p> <p>2014-12-01</p> <p>The structure of forest and diversity of <span class="hlt">tree</span> <span class="hlt">species</span> in temperate mountains have been influenced by changing climate conditions as well as successional changes. To understand how <span class="hlt">tree</span> <span class="hlt">species</span> composition and stand structure change across temperate mountains, the <span class="hlt">species</span> composition, size, and environmental information were collected over the past fourteen years in 880 quadrats of 20 m x 50 m of woodland communities distributed across Jiri and Baekoon Mountains, South Korea. The preliminary investigation on variations of <span class="hlt">tree</span> <span class="hlt">species</span> revealed that overall composition of <span class="hlt">tree</span> <span class="hlt">species</span> increased in terms of both diversity and biomass growth of <span class="hlt">tree</span> <span class="hlt">species</span>, reflecting fast and wide changes in temperate forests of Korea. Among dominant <span class="hlt">trees</span>, the Quercus mongolica, Styrax japonicu, and Acer pseudosieboldianum recorded the highest increase in stand density, implying the most prosperous <span class="hlt">species</span> under current conditions, while the <span class="hlt">species</span> of Quercus variabilis and Fraxinus mandshurica appeared as fast declining <span class="hlt">species</span> in the number. In terms of biomass growth of dominant <span class="hlt">species</span>, the Stewartia pseudocamellia showed the largest increase of biomass, followed by Quercus serrata and Quercus mongolica., while the Fraxinus mandshurica appeared to have a rapid decline, followed by Alnus japonica and Quercus dentata. Overall, the fast change of composition in <span class="hlt">tree</span> <span class="hlt">species</span> is clear and further analysis to clarify the reasons for such fast and <span class="hlt">species</span>-specific changes is underway especially to separate the effect of successional change and climate change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/11737299','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/11737299"><span id="translatedtitle">Fine-scale spatial genetic structure of eight tropical <span class="hlt">tree</span> <span class="hlt">species</span> as analysed by RAPDs.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Degen, B; Caron, H; Bandou, E; Maggia, L; Chevallier, M H; Leveau, A; Kremer, A</p> <p>2001-10-01</p> <p>The fine-scale spatial genetic structure of eight tropical <span class="hlt">tree</span> <span class="hlt">species</span> (Chrysophyllum sanguinolentum, Carapa procera, Dicorynia guianensis, Eperua grandiflora, Moronobea coccinea, Symphonia globulifera, Virola michelii, Vouacapoua americana) was studied in populations that were part of a silvicultural trial in French Guiana. The <span class="hlt">species</span> analysed have different spatial distribution, sexual system, pollen and seed dispersal agents, flowering phenology and environmental demands. The spatial position of <span class="hlt">trees</span> and a RAPD data set for each <span class="hlt">species</span> were combined using a multivariate genetic distance method to estimate spatial genetic structure. A significant spatial genetic structure was found for four of the eight <span class="hlt">species</span>. In contrast to most observations in temperate forests, where spatial structure is not usually detected at distances greater than 50 m, significant genetic structure was found at distances up to 300 m. The relationships between spatial genetic structure and life history characteristics are discussed. PMID:11737299</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25555688','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25555688"><span id="translatedtitle">Characterization of mariner-like transposons of the mauritiana Subfamily in seven <span class="hlt">tree</span> aphid <span class="hlt">species</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kharrat, Imen; Mezghani, Maha; Casse, Nathalie; Denis, Françoise; Caruso, Aurore; Makni, Hanem; Capy, Pierre; Rouault, Jacques-Deric; Chénais, Benoît; Makni, Mohamed</p> <p>2015-02-01</p> <p>Mariner-like elements (MLEs) are Class II transposons present in all eukaryotic genomes in which MLEs have been searched for. This article reports the detection of MLEs in seven of the main fruit <span class="hlt">tree</span> aphid <span class="hlt">species</span> out of eight <span class="hlt">species</span> studied. Deleted MLE sequences of 916-919 bp were characterized, using the terminal-inverted repeats (TIRs) of mariner elements belonging to the mauritiana Subfamily as primers. All the sequences detected were deleted copies of full-length elements that included the 3'- and 5'-TIRs but displayed internal deletions affecting Mos1 activity. Networks based on the mtDNA cytochrome oxidase subunit-I (CO-I) and MLE sequences were incongruent, suggesting that mutations in transposon sequences had accumulated before speciation of <span class="hlt">tree</span> aphid <span class="hlt">species</span> occurred, and that they have been maintained in this <span class="hlt">species</span> via vertical transmissions. This is the first evidence of the widespread occurrence of MLEs in aphids. PMID:25555688</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=89709','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=89709"><span id="translatedtitle">In Vitro Activities of Ketoconazole, Econazole, Miconazole, and Melaleuca alternifolia (Tea <span class="hlt">Tree</span>) Oil against Malassezia <span class="hlt">Species</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hammer, K. A.; Carson, C. F.; Riley, T. V.</p> <p>2000-01-01</p> <p>The in vitro activities of ketoconazole, econazole, miconazole, and tea <span class="hlt">tree</span> oil against 54 Malassezia isolates were determined by agar and broth dilution methods. Ketoconazole was more active than both econazole and miconazole, which showed very similar activities. M. furfur was the least susceptible <span class="hlt">species</span>. M. sympodialis, M. slooffiae, M. globosa, and M. obtusa showed similar susceptibilities to the four agents. PMID:10639388</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/19256435','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/19256435"><span id="translatedtitle">[Reproductive phenology of <span class="hlt">tree</span> <span class="hlt">species</span> in the Tenosique tropical forest, Tabasco, Mexico].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ochoa-Gaona, Susana; Hernández, Isidro Pérez; de Jong, Bernardus H J</p> <p>2008-06-01</p> <p>Between August 2003 and August 2005 we registered the flowering and fruiting of 75 <span class="hlt">tree</span> <span class="hlt">species</span> (341 individual <span class="hlt">trees</span>) in a tropical rain forest at Tenosique, Tabasco, Mexico. Monthly we checked five transects (500 m long; 5 m wide). To test the homogeneity of flowering and fruiting during the year, and between adjacent months, we applied a chi2 test. The flowering was bimodal, with a highest peak in March and April, coinciding with the dry season, and a second lower peak in July when precipitation is relatively low. The highest number of fruiting <span class="hlt">tree</span> <span class="hlt">species</span> occur between May and July, with its peak in May. Each of the most common botanical families showed a particular phenological pattern. Monthly rainfall and the number of <span class="hlt">species</span> flowering or fruiting were not significantly correlated. This means that <span class="hlt">trees</span> are flowering and fruiting all year long, with seasonal increases of both phenological phenomena in the dryer periods. We conclude that phenological patterns vary between individuals and between years and are not seasonally correlated. The data we generated are relevant to program the best periods of seed collections according to individual or groups of <span class="hlt">species</span>, as part of forest management and conservation practices. PMID:19256435</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26164201','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26164201"><span id="translatedtitle">New flux based dose-response relationships for ozone for European forest <span class="hlt">tree</span> <span class="hlt">species</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Büker, P; Feng, Z; Uddling, J; Briolat, A; Alonso, R; Braun, S; Elvira, S; Gerosa, G; Karlsson, P E; Le Thiec, D; Marzuoli, R; Mills, G; Oksanen, E; Wieser, G; Wilkinson, M; Emberson, L D</p> <p>2015-11-01</p> <p>To derive O3 dose-response relationships (DRR) for five European forest <span class="hlt">trees</span> <span class="hlt">species</span> and broadleaf deciduous and needleleaf <span class="hlt">tree</span> plant functional types (PFTs), phytotoxic O3 doses (PODy) were related to biomass reductions. PODy was calculated using a stomatal flux model with a range of cut-off thresholds (y) indicative of varying detoxification capacities. Linear regression analysis showed that DRR for PFT and individual <span class="hlt">tree</span> <span class="hlt">species</span> differed in their robustness. A simplified parameterisation of the flux model was tested and showed that for most non-Mediterranean <span class="hlt">tree</span> <span class="hlt">species</span>, this simplified model led to similarly robust DRR as compared to a <span class="hlt">species</span>- and climate region-specific parameterisation. Experimentally induced soil water stress was not found to substantially reduce PODy, mainly due to the short duration of soil water stress periods. This study validates the stomatal O3 flux concept and represents a step forward in predicting O3 damage to forests in a spatially and temporally varying climate. PMID:26164201</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25065257','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25065257"><span id="translatedtitle">Responses of <span class="hlt">tree</span> <span class="hlt">species</span> to heat waves and extreme heat events.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Teskey, Robert; Wertin, Timothy; Bauweraerts, Ingvar; Ameye, Maarten; McGuire, Mary Anne; Steppe, Kathy</p> <p>2015-09-01</p> <p>The number and intensity of heat waves has increased, and this trend is likely to continue throughout the 21st century. Often, heat waves are accompanied by drought conditions. It is projected that the global land area experiencing heat waves will double by 2020, and quadruple by 2040. Extreme heat events can impact a wide variety of <span class="hlt">tree</span> functions. At the leaf level, photosynthesis is reduced, photooxidative stress increases, leaves abscise and the growth rate of remaining leaves decreases. In some <span class="hlt">species</span>, stomatal conductance increases at high temperatures, which may be a mechanism for leaf cooling. At the whole plant level, heat stress can decrease growth and shift biomass allocation. When drought stress accompanies heat waves, the negative effects of heat stress are exacerbated and can lead to <span class="hlt">tree</span> mortality. However, some <span class="hlt">species</span> exhibit remarkable tolerance to thermal stress. Responses include changes that minimize stress on photosynthesis and reductions in dark respiration. Although there have been few studies to date, there is evidence of within-<span class="hlt">species</span> genetic variation in thermal tolerance, which could be important to exploit in production forestry systems. Understanding the mechanisms of differing <span class="hlt">tree</span> responses to extreme temperature events may be critically important for understanding how <span class="hlt">tree</span> <span class="hlt">species</span> will be affected by climate change. PMID:25065257</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=276289','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=276289"><span id="translatedtitle">Conspecific plant-soil feedbacks of temperate <span class="hlt">tree</span> <span class="hlt">species</span> in the southern Appalachians, USA</span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p>Many <span class="hlt">tree</span> <span class="hlt">species</span> have seedling recruitment patterns suggesting that they are affected by non-competitive distance-dependent sources of mortality. We conducted an experiment, with landscape-level replication, to identify cases of negative distance-dependence effects and whether variation in these e...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=541764','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=541764"><span id="translatedtitle">C4 Photosynthesis in <span class="hlt">Tree</span> Form Euphorbia <span class="hlt">Species</span> from Hawaiian Rainforest Sites 1</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Pearcy, Robert W.; Troughton, John</p> <p>1975-01-01</p> <p>The 13C 12C isotope ratios and the leaf anatomy of 18 <span class="hlt">species</span> and varieties of Euphorbia native to the Hawaian Islands indicated that all possess C4 photosynthesis. These <span class="hlt">species</span> range from small prostrate coastal strand shrubs to shrubs and <span class="hlt">trees</span> in rainforest and bog habitats. The results show that C4 photosynthesis occurs in plants from a much wider range of habitats and life-forms than has been previously reported. PMID:16659208</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70045618','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70045618"><span id="translatedtitle">Effects of canopy <span class="hlt">tree</span> <span class="hlt">species</span> on belowground biogeochemistry in a lowland wet tropical forest</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Keller, Adrienne B.; Reed, Sasha C.; Townsend, Alan R.; Cleveland, Cory C.</p> <p>2013-01-01</p> <p>Tropical rain forests are known for their high biological diversity, but the effects of plant diversity on important ecosystem processes in this biome remain unclear. Interspecies differences in both the demand for nutrients and in foliar and litter nutrient concentrations could drive variations in both the pool sizes and fluxes of important belowground resources, yet our understanding of the effects and importance of aboveground heterogeneity on belowground biogeochemistry is poor, especially in the <span class="hlt">species</span>-rich forests of the wet tropics. To investigate the effects of individual <span class="hlt">tree</span> <span class="hlt">species</span> on belowground biogeochemical processes, we used both field and laboratory studies to examine how carbon (C), nitrogen (N), and phosphorus (P) cycles vary under nine different canopy <span class="hlt">tree</span> <span class="hlt">species</span> – including three legume and six non-legume <span class="hlt">species</span> – that vary in foliar nutrient concentrations in a wet tropical forest in southwestern Costa Rica. We found significant differences in belowground C, N and P cycling under different canopy <span class="hlt">tree</span> <span class="hlt">species</span>: total C, N and P pools in standing litter varied by <span class="hlt">species</span>, as did total soil and microbial C and N pools. Rates of soil extracellular acid phosphatase activity also varied significantly among <span class="hlt">species</span> and functional groups, with higher rates of phosphatase activity under legumes. In addition, across all <span class="hlt">tree</span> <span class="hlt">species</span>, phosphatase activity was significantly positively correlated with litter N/P ratios, suggesting a tight coupling between relative N and P inputs and resource allocation to P acquisition. Overall, our results suggest the importance of aboveground plant community composition in promoting belowground biogeochemical heterogeneity at relatively small spatial scales.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005HMR....59..310S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005HMR....59..310S&link_type=ABSTRACT"><span id="translatedtitle">A new and <span class="hlt">alien</span> <span class="hlt">species</span> of ``oyster leech'' (Platyhelminthes, Polycladida, Stylochidae) from the brackish North Sea Canal, The Netherlands</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sluys, Ronald; Faubel, Anno; Rajagopal, Sanjeevi; Velde, Gerard Van Der</p> <p>2005-11-01</p> <p>A new <span class="hlt">species</span> of polyclad flatworm, Imogine necopinata Sluys, sp. nov., is described from a brackish habitat in The Netherlands. Taxonomic affinities with Asian <span class="hlt">species</span> and the ecology of the animals suggest that the <span class="hlt">species</span> is an introduced, exotic component of the Dutch fauna. The new <span class="hlt">species</span> belongs to a group of worms with <span class="hlt">species</span> that are known to predate on oysters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/5224196','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/5224196"><span id="translatedtitle">Narrowing historical uncertainty: probabilistic classification of ambiguously identified <span class="hlt">tree</span> <span class="hlt">species</span> in historical forest survey data</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Mladenoff, D.J.; Dahir, S.E.; Nordheim, E.V.; Schulte, L.A.; Guntenspergen, G.R.</p> <p>2002-01-01</p> <p>Historical data have increasingly become appreciated for insight into the past conditions of ecosystems. Uses of such data include assessing the extent of ecosystem change; deriving ecological baselines for management, restoration, and modeling; and assessing the importance of past conditions on the composition and function of current systems. One historical data set of this type is the Public Land Survey (PLS) of the United States General Land Office, which contains data on multiple <span class="hlt">tree</span> <span class="hlt">species</span>, sizes, and distances recorded at each survey point, located at half-mile (0.8 km) intervals on a 1-mi (1.6 km) grid. This survey method was begun in the 1790s on US federal lands extending westward from Ohio. Thus, the data have the potential of providing a view of much of the US landscape from the mid-1800s, and they have been used extensively for this purpose. However, historical data sources, such as those describing the <span class="hlt">species</span> composition of forests, can often be limited in the detail recorded and the reliability of the data, since the information was often not originally recorded for ecological purposes. Forest <span class="hlt">trees</span> are sometimes recorded ambiguously, using generic or obscure common names. For the PLS data of northern Wisconsin, USA, we developed a method to classify ambiguously identified <span class="hlt">tree</span> <span class="hlt">species</span> using logistic regression analysis, using data on <span class="hlt">trees</span> that were clearly identified to <span class="hlt">species</span> and a set of independent predictor variables to build the models. The models were first created on partial data sets for each <span class="hlt">species</span> and then tested for fit against the remaining data. Validations were conducted using repeated, random subsets of the data. Model prediction accuracy ranged from 81% to 96% in differentiating congeneric <span class="hlt">species</span> among oak, pine, ash, maple, birch, and elm. Major predictor variables were <span class="hlt">tree</span> size, associated <span class="hlt">species</span>, landscape classes indicative of soil type, and spatial location within the study region. Results help to clarify ambiguities</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.B52C..06K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.B52C..06K"><span id="translatedtitle">Leaf nitrate assimilation during leaf expansion period: comparison of temperate and boreal <span class="hlt">tree</span> <span class="hlt">species</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Koyama, L.; Tokuchi, N.; Kielland, K.</p> <p>2011-12-01</p> <p>We examined nitrate assimilation in several <span class="hlt">tree</span> <span class="hlt">species</span> to test the hypothesis that plant N acquisition is highest in early spring due to the N demands of leaf growth and the seasonal availability of soil N. Specifically, we advance the idea that <span class="hlt">trees</span> acquire N most actively during the leaf expansion period, which serves to offset growth-dilution of foliar N. However, it has been observed that boreal <span class="hlt">species</span> expand their leaves more rapidly than do temperate <span class="hlt">species</span>, suggesting that they exhibit a different seasonal pattern of N acquisition than do temperate <span class="hlt">species</span>. To examine these relationships we measured leaf nitrate reductase activity (NRA) as a proxy for nitrate assimilation, leaf expansion rates, and foliar N concentrations on three boreal <span class="hlt">tree</span> <span class="hlt">species</span> and three temperate <span class="hlt">tree</span> <span class="hlt">species</span> throughout their leaf expansion period. An evergreen <span class="hlt">species</span> (Quercus glauca) and two deciduous <span class="hlt">species</span> (Acer palmatum and Zelkova serrata) were investigated in temperate Japan, and three deciduous <span class="hlt">species</span> Alnus crispa, Betula papyrifera and Populus tremuloides were chosen in a boreal forest in interior Alaska, US. The patterns of foliar N concentrations were very similar across all six <span class="hlt">species</span>, but the mean leaf expansion period was shorter in the boreal <span class="hlt">species</span> (about 25 days) than in temperate <span class="hlt">species</span> (about 29 days). All temperate <span class="hlt">species</span> showed clear peaks of leaf NRA in the middle of leaf expansion period, suggesting that leaves partly compensate for the N dilution during expansion via foliar nitrate assimilation, and that plant nitrate acquisition was effectively timed to coincide with soil N availability generally increased in early spring. By contrast, peak NRA in the boreal <span class="hlt">species</span> were observed in different stage of leaf expansion, but as in the temperate <span class="hlt">species</span> declined to very low levels after the leaves were fully expanded. Our results demonstrate that plant nitrate assimilation is concentrated during leaf expansion in spring and early summer, but declines to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27481793','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27481793"><span id="translatedtitle">The Trichoptera barcode initiative: a strategy for generating a <span class="hlt">species</span>-level <span class="hlt">Tree</span> of Life.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhou, Xin; Frandsen, Paul B; Holzenthal, Ralph W; Beet, Clare R; Bennett, Kristi R; Blahnik, Roger J; Bonada, Núria; Cartwright, David; Chuluunbat, Suvdtsetseg; Cocks, Graeme V; Collins, Gemma E; deWaard, Jeremy; Dean, John; Flint, Oliver S; Hausmann, Axel; Hendrich, Lars; Hess, Monika; Hogg, Ian D; Kondratieff, Boris C; Malicky, Hans; Milton, Megan A; Morinière, Jérôme; Morse, John C; Mwangi, François Ngera; Pauls, Steffen U; Gonzalez, María Razo; Rinne, Aki; Robinson, Jason L; Salokannel, Juha; Shackleton, Michael; Smith, Brian; Stamatakis, Alexandros; StClair, Ros; Thomas, Jessica A; Zamora-Muñoz, Carmen; Ziesmann, Tanja; Kjer, Karl M</p> <p>2016-09-01</p> <p>DNA barcoding was intended as a means to provide <span class="hlt">species</span>-level identifications through associating DNA sequences from unknown specimens to those from curated reference specimens. Although barcodes were not designed for phylogenetics, they can be beneficial to the completion of the <span class="hlt">Tree</span> of Life. The barcode database for Trichoptera is relatively comprehensive, with data from every family, approximately two-thirds of the genera, and one-third of the described <span class="hlt">species</span>. Most Trichoptera, as with most of life's <span class="hlt">species</span>, have never been subjected to any formal phylogenetic analysis. Here, we present a phylogeny with over 16 000 unique haplotypes as a working hypothesis that can be updated as our estimates improve. We suggest a strategy of implementing constrained <span class="hlt">tree</span> searches, which allow larger datasets to dictate the backbone phylogeny, while the barcode data fill out the tips of the <span class="hlt">tree</span>. We also discuss how this phylogeny could be used to focus taxonomic attention on ambiguous <span class="hlt">species</span> boundaries and hidden biodiversity. We suggest that systematists continue to differentiate between 'Barcode Index Numbers' (BINs) and '<span class="hlt">species</span>' that have been formally described. Each has utility, but they are not synonyms. We highlight examples of integrative taxonomy, using both barcodes and morphology for <span class="hlt">species</span> description.This article is part of the themed issue 'From DNA barcodes to biomes'. PMID:27481793</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4406680','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4406680"><span id="translatedtitle">Mapping and Characterizing Selected Canopy <span class="hlt">Tree</span> <span class="hlt">Species</span> at the Angkor World Heritage Site in Cambodia Using Aerial Data</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Singh, Minerva; Evans, Damian; Tan, Boun Suy; Nin, Chan Samean</p> <p>2015-01-01</p> <p>At present, there is very limited information on the ecology, distribution, and structure of Cambodia’s <span class="hlt">tree</span> <span class="hlt">species</span> to warrant suitable conservation measures. The aim of this study was to assess various methods of analysis of aerial imagery for characterization of the forest mensuration variables (i.e., <span class="hlt">tree</span> height and crown width) of selected <span class="hlt">tree</span> <span class="hlt">species</span> found in the forested region around the temples of Angkor Thom, Cambodia. Object-based image analysis (OBIA) was used (using multiresolution segmentation) to delineate individual <span class="hlt">tree</span> crowns from very-high-resolution (VHR) aerial imagery and light detection and ranging (LiDAR) data. Crown width and <span class="hlt">tree</span> height values that were extracted using multiresolution segmentation showed a high level of congruence with field-measured values of the <span class="hlt">trees</span> (Spearman’s rho 0.782 and 0.589, respectively). Individual <span class="hlt">tree</span> crowns that were delineated from aerial imagery using multiresolution segmentation had a high level of segmentation accuracy (69.22%), whereas <span class="hlt">tree</span> crowns delineated using watershed segmentation underestimated the field-measured <span class="hlt">tree</span> crown widths. Both spectral angle mapper (SAM) and maximum likelihood (ML) classifications were applied to the aerial imagery for mapping of selected <span class="hlt">tree</span> <span class="hlt">species</span>. The latter was found to be more suitable for <span class="hlt">tree</span> <span class="hlt">species</span> classification. Individual <span class="hlt">tree</span> <span class="hlt">species</span> were identified with high accuracy. Inclusion of textural information further improved <span class="hlt">species</span> identification, albeit marginally. Our findings suggest that VHR aerial imagery, in conjunction with OBIA-based segmentation methods (such as multiresolution segmentation) and supervised classification techniques are useful for <span class="hlt">tree</span> <span class="hlt">species</span> mapping and for studies of the forest mensuration variables. PMID:25902148</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25902148','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25902148"><span id="translatedtitle">Mapping and characterizing selected canopy <span class="hlt">tree</span> <span class="hlt">species</span> at the Angkor World Heritage site in Cambodia using aerial data.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Singh, Minerva; Evans, Damian; Tan, Boun Suy; Nin, Chan Samean</p> <p>2015-01-01</p> <p>At present, there is very limited information on the ecology, distribution, and structure of Cambodia's <span class="hlt">tree</span> <span class="hlt">species</span> to warrant suitable conservation measures. The aim of this study was to assess various methods of analysis of aerial imagery for characterization of the forest mensuration variables (i.e., <span class="hlt">tree</span> height and crown width) of selected <span class="hlt">tree</span> <span class="hlt">species</span> found in the forested region around the temples of Angkor Thom, Cambodia. Object-based image analysis (OBIA) was used (using multiresolution segmentation) to delineate individual <span class="hlt">tree</span> crowns from very-high-resolution (VHR) aerial imagery and light detection and ranging (LiDAR) data. Crown width and <span class="hlt">tree</span> height values that were extracted using multiresolution segmentation showed a high level of congruence with field-measured values of the <span class="hlt">trees</span> (Spearman's rho 0.782 and 0.589, respectively). Individual <span class="hlt">tree</span> crowns that were delineated from aerial imagery using multiresolution segmentation had a high level of segmentation accuracy (69.22%), whereas <span class="hlt">tree</span> crowns delineated using watershed segmentation underestimated the field-measured <span class="hlt">tree</span> crown widths. Both spectral angle mapper (SAM) and maximum likelihood (ML) classifications were applied to the aerial imagery for mapping of selected <span class="hlt">tree</span> <span class="hlt">species</span>. The latter was found to be more suitable for <span class="hlt">tree</span> <span class="hlt">species</span> classification. Individual <span class="hlt">tree</span> <span class="hlt">species</span> were identified with high accuracy. Inclusion of textural information further improved <span class="hlt">species</span> identification, albeit marginally. Our findings suggest that VHR aerial imagery, in conjunction with OBIA-based segmentation methods (such as multiresolution segmentation) and supervised classification techniques are useful for <span class="hlt">tree</span> <span class="hlt">species</span> mapping and for studies of the forest mensuration variables. PMID:25902148</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18608895','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18608895"><span id="translatedtitle">The expanding host <span class="hlt">tree</span> <span class="hlt">species</span> spectrum of Cryptococcus gattii and Cryptococcus neoformans and their isolations from surrounding soil in India.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Randhawa, H S; Kowshik, T; Chowdhary, Anuradha; Preeti Sinha, K; Khan, Z U; Sun, Sheng; Xu, Jianping</p> <p>2008-12-01</p> <p>This study reports the widespread prevalence of Cryptococcus neoformans and Cryptococcus gattii in decayed wood inside trunk hollows of 14 <span class="hlt">species</span> representing 12 families of <span class="hlt">trees</span> and from soil near the base of various host <span class="hlt">trees</span> from Delhi and several places in the Indian states of Uttar Pradesh, Haryana, Tamil Nadu and Chandigarh Union Territory. Of the 311 <span class="hlt">trees</span> from which samples were obtained, 64 (20.5%) were found to contain strains of the C. neoformans <span class="hlt">species</span> complex. The number of <span class="hlt">trees</span> positive for C. neoformans var grubii (serotypeA) was 51 (16.3%), for C. gattii (serotype B) 24 (7.7%) and for both C. neoformans and C. gattii 11 (3.5%). The overall prevalence of C. neoformans <span class="hlt">species</span> complex in decayed wood samples was 19.9% (111/556). There was no obvious correlation between the prevalence of these two yeast <span class="hlt">species</span> and the <span class="hlt">species</span> of host <span class="hlt">trees</span>. The data on prevalence of C. gattii (24%) and C. neoformans (26%) in soil around the base of some host <span class="hlt">trees</span> indicated that soil is another important ecologic niche for these two Cryptococcus <span class="hlt">species</span> in India. Among our sampled <span class="hlt">tree</span> <span class="hlt">species</span>, eight and six were recorded for the first time as hosts for C. neoformans var grubii and C. gattii, respectively. A longitudinal surveillance of 8 host <span class="hlt">tree</span> <span class="hlt">species</span> over 0.7 to 2.5 years indicated long term colonization of Polyalthia longifolia, Mimusops elengi and Manilkara hexandra <span class="hlt">trees</span> by C. gattii and/or C. neoformans. The mating type was determined for 153 of the isolates, including 98 strains of serotype A and 55 of serotype B and all proved to be mating type alpha (MAT alpha). Our observations document the rapidly expanding spectrum of host <span class="hlt">tree</span> <span class="hlt">species</span> for C. gattii and C. neoformans and indicate that decayed woods of many <span class="hlt">tree</span> <span class="hlt">species</span> are potentially suitable ecological niches for both pathogens. PMID:18608895</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140009601','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140009601"><span id="translatedtitle"><span class="hlt">Tree</span> Density and <span class="hlt">Species</span> Decline in the African Sahel Attributable to Climate</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gonzalez, Patrick; Tucker, Compton J.; Sy, H.</p> <p>2012-01-01</p> <p>Increased aridity and human population have reduced <span class="hlt">tree</span> cover in parts of the African Sahel and degraded resources for local people. Yet, <span class="hlt">tree</span> cover trends and the relative importance of climate and population remain unresolved. From field measurements, aerial photos, and Ikonos satellite images, we detected significant 1954-2002 <span class="hlt">tree</span> density declines in the western Sahel of 18 +/- 14% (P = 0.014, n = 204) and 17 +/- 13% (P = 0.0009, n = 187). From field observations, we detected a significant 1960-2000 <span class="hlt">species</span> richness decline of 21 +/- 11% (P = 0.0028, n = 14) across the Sahel and a southward shift of the Sahel, Sudan, and Guinea zones. Multivariate analyses of climate, soil, and population showed that temperature most significantly (P < 0.001) explained <span class="hlt">tree</span> cover changes. Multivariate and bivariate tests and field observations indicated the dominance of temperature and precipitation, supporting attribution of <span class="hlt">tree</span> cover changes to climate variability. Climate change forcing of Sahel climate variability, particularly the significant (P < 0.05) 1901-2002 temperature increases and precipitation decreases in the research areas, connects Sahel <span class="hlt">tree</span> cover changes to global climate change. This suggests roles for global action and local adaptation to address ecological change in the Sahel.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27353660','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27353660"><span id="translatedtitle">Spatial and taxonomical overlap of fungi on phylloplanes and invasive <span class="hlt">alien</span> ladybirds with fungal infections in <span class="hlt">tree</span> crowns of urban green spaces.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Howe, Andy G; Ravn, Hans Peter; Jensen, Annette B; Meyling, Nicolai V</p> <p>2016-09-01</p> <p>Occurrence of entomopathogenic fungi on phylloplanes in Tilia × europaea crowns between 1 and 13 m was assessed in urban parks. Prevalence of fungal infections in ladybirds (Coleoptera: Coccinellidae) collected from Tilia × europaea was assessed to determine whether fungi found on phylloplanes also occurred as infections in ladybirds. Isaria spp. was most abundant on phylloplanes (mean colony forming units (CFU) per leaf ± SE, 0.33 ± 0.03) followed by Beauveria spp. (0.22 ± 0.02 CFU per leaf) and Lecanicillium spp. (0.19 ± 0.02 CFU per leaf). Densities of inoculum were higher in inner crowns and decreased with height, although Lecanicillium spp. peaked at 5-7 m. Upper phylloplane surfaces harboured higher densities of Isaria spp. and Beauveria spp. than lower surfaces, whereas Lecanicillium spp. was equally distributed. Most prevalent on ladybirds were Isaria spp. (20.6% Harmonia axyridis; 4.8% natives), Lecanicillium spp. (13.6% H. axyridis; 4.8% natives), with fewer Beauveria spp. infections (2.6% H. axyridis). Molecular identification revealed Beauveria bassiana, B. pseudobassiana, Isaria farinosa and Lecanicillium muscarium among isolates of both <span class="hlt">tree</span> and ladybird origin. Tilia × europaea phylloplanes support a diverse assemblage of entomopathogenic fungal <span class="hlt">species</span> with a different prevalence in coccinellids compared to their relative abundance in this habitat. PMID:27353660</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25526843','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25526843"><span id="translatedtitle"><span class="hlt">Tree</span> <span class="hlt">species</span> diversity mitigates disturbance impacts on the forest carbon cycle.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pedro, Mariana Silva; Rammer, Werner; Seidl, Rupert</p> <p>2015-03-01</p> <p>Biodiversity fosters the functioning and stability of forest ecosystems and, consequently, the provision of crucial ecosystem services that support human well-being and quality of life. In particular, it has been suggested that <span class="hlt">tree</span> <span class="hlt">species</span> diversity buffers ecosystems against the impacts of disturbances, a relationship known as the "insurance hypothesis". Natural disturbances have increased across Europe in recent decades and climate change is expected to amplify the frequency and severity of disturbance events. In this context, mitigating disturbance impacts and increasing the resilience of forest ecosystems is of growing importance. We have tested how <span class="hlt">tree</span> <span class="hlt">species</span> diversity modulates the impact of disturbance on net primary production and the total carbon stored in living biomass for a temperate forest landscape in Central Europe. Using the simulation model iLand to study the effect of different disturbance regimes on landscapes with varying levels of <span class="hlt">tree</span> <span class="hlt">species</span> richness, we found that increasing diversity generally reduces the disturbance impact on carbon storage and uptake, but that this effect weakens or even reverses with successional development. Our simulations indicate a clear positive relationship between diversity and resilience, with more diverse systems experiencing lower disturbance-induced variability in their trajectories of ecosystem functioning. We found that positive effects of <span class="hlt">tree</span> <span class="hlt">species</span> diversity are mainly driven by an increase in functional diversity and a modulation of traits related to recolonization and resource usage. The results of our study suggest that increasing <span class="hlt">tree</span> <span class="hlt">species</span> diversity could mitigate the effects of intensifying disturbance regimes on ecosystem functioning and improve the robustness of forest carbon storage and the role of forests in climate change mitigation. PMID:25526843</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3626689','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3626689"><span id="translatedtitle">Winning and Losing <span class="hlt">Tree</span> <span class="hlt">Species</span> of Reassembly in Minnesota’s Mixed and Broadleaf Forests</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hanberry, Brice B.; Palik, Brian J.; He, Hong S.</p> <p>2013-01-01</p> <p>We examined reassembly of winning and losing <span class="hlt">tree</span> <span class="hlt">species</span>, <span class="hlt">species</span> traits including shade and fire tolerance, and associated disturbance filters and forest ecosystem types due to rapid forest change in the Great Lakes region since 1850. We identified winning and losing <span class="hlt">species</span> by changes in composition, distribution, and site factors between historical and current surveys in Minnesota’s mixed and broadleaf forests. In the Laurentian Mixed Forest, shade-intolerant aspen replaced shade-intolerant tamarack as the most dominant <span class="hlt">tree</span> <span class="hlt">species</span>. Fire-tolerant white pine and jack pine decreased, whereas shade-tolerant ashes, maples, and white cedar increased. In the Eastern Broadleaf Forest, fire-tolerant white oaks and red oaks decreased, while shade-tolerant ashes, American basswood, and maples increased. Tamarack, pines, and oaks have become restricted to sites with either wetter or sandier and drier soils due to increases in aspen and shade-tolerant, fire-sensitive <span class="hlt">species</span> on mesic sites. The proportion of shade-tolerant <span class="hlt">species</span> increased in both regions, but selective harvest reduced the applicability of functional groups alone to specify winners and losers. Harvest and existing forestry practices supported aspen dominance in mixed forests, although without aspen forestry and with fire suppression, mixed forests will transition to a greater composition of shade-tolerant <span class="hlt">species</span>, converging to forests similar to broadleaf forests. A functional group framework provided a perspective of winning and losing <span class="hlt">species</span> and traits, selective filters, and forest ecosystems that can be generalized to other regions, regardless of <span class="hlt">species</span> identity. PMID:23613911</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2714761','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2714761"><span id="translatedtitle">Temperature dependence, spatial scale, and <span class="hlt">tree</span> <span class="hlt">species</span> diversity in eastern Asia and North America</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wang, Zhiheng; Brown, James H.; Tang, Zhiyao; Fang, Jingyun</p> <p>2009-01-01</p> <p>The increase of biodiversity from poles to equator is one of the most pervasive features of nature. For 2 centuries since von Humboldt, Wallace, and Darwin, biogeographers and ecologists have investigated the environmental and historical factors that determine the latitudinal gradient of <span class="hlt">species</span> diversity, but the underlying mechanisms remain poorly understood. The recently proposed metabolic theory of ecology (MTE) aims to explain ecological patterns and processes, including geographical patterns of <span class="hlt">species</span> richness, in terms of the effects of temperature and body size on the metabolism of organisms. Here we use 2 comparable databases of <span class="hlt">tree</span> distributions in eastern Asia and North America to investigate the roles of environmental temperature and spatial scale in shaping geographical patterns of <span class="hlt">species</span> diversity. We find that number of <span class="hlt">species</span> increases exponentially with environmental temperature as predicted by the MTE, and so does the rate of spatial turnover in <span class="hlt">species</span> composition (slope of the <span class="hlt">species</span>-area relationship). The magnitude of temperature dependence of <span class="hlt">species</span> richness increases with spatial scale. Moreover, the relationship between <span class="hlt">species</span> richness and temperature is much steeper in eastern Asia than in North America: in cold climates at high latitudes there are more <span class="hlt">tree</span> <span class="hlt">species</span> in North America, but the reverse is true in warmer climates at lower latitudes. These patterns provide evidence that the kinetics of ecological and evolutionary processes play a major role in the latitudinal pattern of biodiversity. PMID:19628692</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16995629','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16995629"><span id="translatedtitle"><span class="hlt">Tree</span> <span class="hlt">species</span> effects on decomposition and forest floor dynamics in a common garden.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hobbie, Sarah E; Reich, Peter B; Oleksyn, Jacek; Ogdahl, Megan; Zytkowiak, Roma; Hale, Cynthia; Karolewski, Piotr</p> <p>2006-09-01</p> <p>We studied the effects of <span class="hlt">tree</span> <span class="hlt">species</span> on leaf litter decomposition and forest floor dynamics in a common garden experiment of 14 <span class="hlt">tree</span> <span class="hlt">species</span> (Abies alba, Acer platanoides, Acer pseudoplatanus, Betula pendula, Carpinus betulus, Fagus sylvatica, Larix decidua, Picea abies, Pinus nigra, Pinus sylvestris, Pseudotsuga menziesii, Quercus robur, Quercus rubra, and Tilia cordata) in southwestern Poland. We used three simultaneous litter bag experiments to tease apart <span class="hlt">species</span> effects on decomposition via leaf litter chemistry vs. effects on the decomposition environment. Decomposition rates of litter in its plot of origin were negatively correlated with litter lignin and positively correlated with mean annual soil temperature (MAT(soil)) across <span class="hlt">species</span>. Likewise, decomposition of a common litter type across all plots was positively associated with MAT(soil), and decomposition of litter from all plots in a common plot was negatively related to litter lignin but positively related to litter Ca. Taken together, these results indicate that <span class="hlt">tree</span> <span class="hlt">species</span> influenced microbial decomposition primarily via differences in litter lignin (and secondarily, via differences in litter Ca), with high-lignin (and low-Ca) <span class="hlt">species</span> decomposing most slowly, and by affecting MAT(soil), with warmer plots exhibiting more rapid decomposition. In addition to litter bag experiments, we examined forest floor dynamics in each plot by mass balance, since earthworms were a known component of these forest stands and their access to litter in litter bags was limited. Forest floor removal rates estimated from mass balance were positively related to leaf litter Ca (and unrelated to decay rates obtained using litter bags). Litter Ca, in turn, was positively related to the abundance of earthworms, particularly Lumbricus terrestris. Thus, while <span class="hlt">species</span> influence microbially mediated decomposition primarily through differences in litter lignin, differences among <span class="hlt">species</span> in litter Ca are most important in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JGRG..117.0N16Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JGRG..117.0N16Z"><span id="translatedtitle">Large difference of inhibitive effect of nitrogen deposition on soil methane oxidation between plantations with N-fixing <span class="hlt">tree</span> <span class="hlt">species</span> and non-N-fixing <span class="hlt">tree</span> <span class="hlt">species</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Wei; Zhu, Xiaomin; Liu, Lei; Fu, Shenglei; Chen, Hao; Huang, Juan; Lu, Xiankai; Liu, Zhanfeng; Mo, Jiangming</p> <p>2012-12-01</p> <p>The responses of soil methane (CH4) net fluxes to nitrogen (N) addition in a N-fixing <span class="hlt">tree</span> <span class="hlt">species</span> (Acacia auriculiformis (AA)) and a non-N-fixing <span class="hlt">tree</span> <span class="hlt">species</span> (Eucalyptus citriodora (EU)) plantation were studied in southern China. Treatments were conducted at each plantation with three N levels (0, 50, and 100 kg N ha-1 yr-1 for control, medium-N, and high-N treatment, respectively, abbreviated as C, MN, and HN). From August 2010 to July 2011, CH4 flux was measured biweekly using a static chamber and gas chromatography technique. The soils of both sites acted as sink of atmospheric CH4. The CH4 uptake rate in control of the AA site (36.3 ± 3.2 μg CH4-C m-2 h-1) was greater than that of the EU plantation (29.9 ± 0.9 μg CH4-C m-2 h-1). In the AA plantation, the averaged rates of CH4 uptake for the MN (28.6 ± 2.3 μg CH4-C m-2 h-1) and HN treatment (23.8 ± 2.8 μg CH4-C m-2 h-1) were decreased by 21% and 35%, respectively, compared to the control. However, there was no change of soil CH4 uptake between N-treated plots and the controls in the EU site. Our results indicated that there might be large difference of inhibitive effect of N deposition on soil CH4 oxidation between the AA and EU plantations. The projected increase of N deposition would weaken the capability of N-fixing <span class="hlt">tree</span> <span class="hlt">species</span> plantations for atmospheric CH4 sink in tropical and subtropical regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/20472645','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/20472645"><span id="translatedtitle">The influence of mixed <span class="hlt">tree</span> plantations on the nutrition of individual <span class="hlt">species</span>: a review.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Richards, Anna E; Forrester, David I; Bauhus, Jürgen; Scherer-Lorenzen, Michael</p> <p>2010-09-01</p> <p>Productivity of <span class="hlt">tree</span> plantations is a function of the supply, capture and efficiency of use of resources, as outlined in the Production Ecology Equation. <span class="hlt">Species</span> interactions in mixed-<span class="hlt">species</span> stands can influence each of these variables. The importance of resource-use efficiency in determining forest productivity has been clearly demonstrated in monocultures; however, substantial knowledge gaps remain for mixtures. This review examines how the physiology and morphology of a given <span class="hlt">species</span> can vary depending on whether it grows in a mixture or monoculture. We outline how physiological and morphological shifts within <span class="hlt">species</span>, resulting from interactions in mixtures, may influence the three variables of the Production Ecology Equation, with an emphasis on nutrient resources [nitrogen (N) and phosphorus (P)]. These include (i) resource availability, including soil nutrient mineralization, N₂ fixation and litter decomposition; (ii) proportion of resources captured, resulting from shifts in spatial, temporal and chemical patterns of root dynamics; (iii) resource-use efficiency. We found that more than 50% of mixed-<span class="hlt">species</span> studies report a shift to greater above-ground nutrient content of <span class="hlt">species</span> grown in mixtures compared to monocultures, indicating an increase in the proportion of resources captured from a site. Secondly, a meta-analysis showed that foliar N concentrations significantly increased for a given <span class="hlt">species</span> in a mixture containing N₂-fixing <span class="hlt">species</span>, compared to a monoculture, suggesting higher rates of photosynthesis and greater resource-use efficiency. Significant shifts in N- and P-use efficiencies of a given <span class="hlt">species</span>, when grown in a mixture compared to a monoculture, occurred in over 65% of studies where resource-use efficiency could be calculated. Such shifts can result from changes in canopy photosynthetic capacities, changes in carbon allocation or changes to foliar nutrient residence times of <span class="hlt">species</span> in a mixture. We recommend that future research</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/283030','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/283030"><span id="translatedtitle">Anatomical, chemical, and ecological factors affecting <span class="hlt">tree</span> <span class="hlt">species</span> choice in dendrochemistry studies</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Cutter, B.E.; Guyette, R.P.</p> <p>1993-07-01</p> <p>Recently, element concentrations in <span class="hlt">tree</span> rings have been used to monitor metal contamination, fertilization, and the effects of acid precipitation on soils. This has stimulated interest in which <span class="hlt">tree</span> <span class="hlt">species</span> may be suitable for use in studies of long-term trends in environmental chemistry. Potential radial translocation of elements across living boundaries can be a confounding factor in assessing environmental change. The selection of <span class="hlt">species</span> which minimizes radial translocation of elements can be critical to the success of dendrochemical research. Criteria for selection of <span class="hlt">species</span> with characteristics favorable for dendrochemical analysis are categorized into (1) habitat-based factors, (2) xylem-based factors, and (3) element-based factors. A wide geographic range and ecological amplitude provide an advantage in calibration and better controls on the effects of soil chemistry. The most important xylem-based criteria are heartwood moisture content, permeability, and the nature of the sapwood-heartwood transition. The element of interest is important in determining suitable <span class="hlt">tree</span> <span class="hlt">species</span> because all elements are not equally mobile or detectable in the xylem. Ideally, the <span class="hlt">tree</span> <span class="hlt">species</span> selected for dendrochemical study will be long-lived, grow on a wide range of sites over a large geographic distribution, have a distinct heartwood with a low number of rings in the sapwood, a low heartwood moisture content, and have low radial permeability. Recommended temperate zone North American <span class="hlt">species</span> include white oak (Quercus alba L.), post oak (Q. stellate Wangenh.), eastern redcedar (funiperus virginiana L.), old-growth Douglas-fir [Pseudoaugu menziesii (Mirb.) Franco] and big sagebrush (Artemisia tridentata Nutt.). In addition, <span class="hlt">species</span> such as bristlecone pine (Pinus aristata Engelm. syn. longaeva), old-growth redwood [Sequoia sempervirens (D. Don) Endl.], and giant sequoia [S. gigantea (Lindl.) Deene] may be suitable for local purposes. 118 refs., 2 tabs.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70025565','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70025565"><span id="translatedtitle">Impacts of the Brown <span class="hlt">Tree</span> Snake: Patterns of Decline and <span class="hlt">Species</span> Persistence in Guam's Avifauna</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Wiles, G.J.; Bart, J.; Beck, R.E., Jr.; Aguon, C.F.</p> <p>2003-01-01</p> <p>Predation by brown <span class="hlt">tree</span> snakes (Boiga irregularis) devastated the avifauna of Guam in the Mariana Islands during the last half of the twentieth century, causing the extirpation or serious reduction of most of the island's 25 resident bird <span class="hlt">species</span>. Past studies have provided qualitative descriptions of the decline of native forest birds but have not considered all <span class="hlt">species</span> or presented quantitative analyses. We analyzed two sets of survey data gathered in northern Guam between 1976 and 1998 and reviewed unpublished sources to provide a comprehensive account of the impact of brown <span class="hlt">tree</span> snakes on the island's birds. Our results indicate that 22 <span class="hlt">species</span>, including 17 of 18 native <span class="hlt">species</span>, were severely affected by snakes. Twelve <span class="hlt">species</span> were likely extirpated as breeding residents on the main island, 8 others experienced declines of ???90% throughout the island or at least in the north, and 2 were kept at reduced population levels during all or much of the study. Declines of ???90% occurred rapidly, averaging just 8.9 years along three roadside survey routes combined and 1.6 years at a 100-ha forested study site. Declines in northern Guam were also relatively synchronous and occurred from about 1976 to 1986 for most <span class="hlt">species</span>. The most important factor predisposing a <span class="hlt">species</span> to coexistence with brown <span class="hlt">tree</span> snakes was its ability to nest and roost at locations where snakes were uncommon. Large clutch size and large body size were also related to longer persistence times, although large body size appeared to delay, but not prevent, extirpation. Our results draw attention to the enormous detrimental impact that brown <span class="hlt">tree</span> snakes are likely to have upon invading new areas. Increased containment efforts on Guam are needed to prevent further colonizations, but a variety of additional management efforts would also benefit the island's remaining bird populations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21302839','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21302839"><span id="translatedtitle">The trait contribution to wood decomposition rates of 15 Neotropical <span class="hlt">tree</span> <span class="hlt">species</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>van Geffen, Koert G; Poorter, Lourens; Sass-Klaassen, Ute; van Logtestijn, Richard S P; Cornelissen, Johannes H C</p> <p>2010-12-01</p> <p>The decomposition of dead wood is a critical uncertainty in models of the global carbon cycle. Despite this, relatively few studies have focused on dead wood decomposition, with a strong bias to higher latitudes. Especially the effect of interspecific variation in <span class="hlt">species</span> traits on differences in wood decomposition rates remains unknown. In order to fill these gaps, we applied a novel method to study long-term wood decomposition of 15 <span class="hlt">tree</span> <span class="hlt">species</span> in a Bolivian semi-evergreen tropical moist forest. We hypothesized that interspecific differences in <span class="hlt">species</span> traits are important drivers of variation in wood decomposition rates. Wood decomposition rates (fractional mass loss) varied between 0.01 and 0.31 yr(-1). We measured 10 different chemical, anatomical, and morphological traits for all <span class="hlt">species</span>. The <span class="hlt">species</span>' average traits were useful predictors of wood decomposition rates, particularly the average diameter (dbh) of the <span class="hlt">tree</span> <span class="hlt">species</span> (R2 = 0.41). Lignin concentration further increased the proportion of explained inter-specific variation in wood decomposition (both negative relations, cumulative R2 = 0.55), although it did not significantly explain variation in wood decomposition rates if considered alone. When dbh values of the actual dead <span class="hlt">trees</span> sampled for decomposition rate determination were used as a predictor variable, the final model (including dead <span class="hlt">tree</span> dbh and lignin concentration) explained even more variation in wood decomposition rates (R2 = 0.71), underlining the importance of dbh in wood decomposition. Other traits, including wood density, wood anatomical traits, macronutrient concentrations, and the amount of phenolic extractives could not significantly explain the variation in wood decomposition rates. The surprising results of this multi-<span class="hlt">species</span> study, in which for the first time a large set of traits is explicitly linked to wood decomposition rates, merits further testing in other forest ecosystems. PMID:21302839</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GPC...133..298B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GPC...133..298B"><span id="translatedtitle">Oxygen isotopes in <span class="hlt">tree</span> rings show good coherence between <span class="hlt">species</span> and sites in Bolivia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baker, Jessica C. A.; Hunt, Sarah F. P.; Clerici, Santiago J.; Newton, Robert J.; Bottrell, Simon H.; Leng, Melanie J.; Heaton, Timothy H. E.; Helle, Gerhard; Argollo, Jaime; Gloor, Manuel; Brienen, Roel J. W.</p> <p>2015-10-01</p> <p>A <span class="hlt">tree</span> ring oxygen isotope (δ18OTR) chronology developed from one <span class="hlt">species</span> (Cedrela odorata) growing in a single site has been shown to be a sensitive proxy for rainfall over the Amazon Basin, thus allowing reconstructions of precipitation in a region where meteorological records are short and scarce. Although these results suggest that there should be large-scale (> 100 km) spatial coherence of δ18OTR records in the Amazon, this has not been tested. Furthermore, it is of interest to investigate whether other, possibly longer-lived, <span class="hlt">species</span> similarly record interannual variation of Amazon precipitation, and can be used to develop climate sensitive isotope chronologies. In this study, we measured δ18O in <span class="hlt">tree</span> rings from seven lowland and one highland <span class="hlt">tree</span> <span class="hlt">species</span> from Bolivia. We found that cross-dating with δ18OTR gave more accurate <span class="hlt">tree</span> ring dates than using ring width. Our "isotope cross-dating approach" is confirmed with radiocarbon "bomb-peak" dates, and has the potential to greatly facilitate development of δ18OTR records in the tropics, identify dating errors, and check annual ring formation in tropical <span class="hlt">trees</span>. Six of the seven lowland <span class="hlt">species</span> correlated significantly with C. odorata, showing that variation in δ18OTR has a coherent imprint across very different <span class="hlt">species</span>, most likely arising from a dominant influence of source water δ18O on δ18OTR. In addition we show that δ18OTR series cohere over large distances, within and between <span class="hlt">species</span>. Comparison of two C. odorata δ18OTR chronologies from sites several hundreds of kilometres apart showed a very strong correlation (r = 0.80, p < 0.001, 1901-2001), and a significant (but weaker) relationship was found between lowland C. odorata <span class="hlt">trees</span> and a Polylepis tarapacana <span class="hlt">tree</span> growing in the distant Altiplano (r = 0.39, p < 0.01, 1931-2001). This large-scale coherence of δ18OTR records is probably triggered by a strong spatial coherence in precipitation δ18O due to large-scale controls. These results</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26663665','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26663665"><span id="translatedtitle">Drought stress limits the geographic ranges of two <span class="hlt">tree</span> <span class="hlt">species</span> via different physiological mechanisms.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Anderegg, Leander D L; HilleRisLambers, Janneke</p> <p>2016-03-01</p> <p>Range shifts are among the most ubiquitous ecological responses to anthropogenic climate change and have large consequences for ecosystems. Unfortunately, the ecophysiological forces that constrain range boundaries are poorly understood, making it difficult to mechanistically project range shifts. To explore the physiological mechanisms by which drought stress controls dry range boundaries in <span class="hlt">trees</span>, we quantified elevational variation in drought tolerance and in drought avoidance-related functional traits of a widespread gymnosperm (ponderosa pine - Pinus ponderosa) and angiosperm (trembling aspen - Populus tremuloides) <span class="hlt">tree</span> <span class="hlt">species</span> in the southwestern USA. Specifically, we quantified <span class="hlt">tree-to-tree</span> variation in growth, water stress (predawn and midday xylem tension), drought avoidance traits (branch conductivity, leaf/needle size, <span class="hlt">tree</span> height, leaf area-to-sapwood area ratio), and drought tolerance traits (xylem resistance to embolism, hydraulic safety margin, wood density) at the range margins and range center of each <span class="hlt">species</span>. Although water stress increased and growth declined strongly at lower range margins of both <span class="hlt">species</span>, ponderosa pine and aspen showed contrasting patterns of clinal trait variation. Trembling aspen increased its drought tolerance at its dry range edge by growing stronger but more carbon dense branch and leaf tissues, implying an increased cost of growth at its range boundary. By contrast, ponderosa pine showed little elevational variation in drought-related traits but avoided drought stress at low elevations by limiting transpiration through stomatal closure, such that its dry range boundary is associated with limited carbon assimilation even in average climatic conditions. Thus, the same climatic factor (drought) may drive range boundaries through different physiological mechanisms - a result that has important implications for process-based modeling approaches to <span class="hlt">tree</span> biogeography. Further, we show that comparing intraspecific patterns of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.2533C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.2533C"><span id="translatedtitle">Different <span class="hlt">tree</span> <span class="hlt">species</span> affect soil respiration spatial distribution in a subtropical forest of southern Taiwan</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chiang, Po-Neng; Yu, Jui-Chu; Wang, Ya-nan; Lai, Yen-Jen</p> <p>2014-05-01</p> <p>Global forests contain 69% of total carbon stored in forest soil and litter. But the carbon storage ability and release rate of warming gases of forest soil also affect global climate change. Soil carbon cycling processes are paid much attention by ecological scientists and policy makers because of the possibility of carbon being stored in soil via land use management. Soil respiration contributed large part of terrestrial carbon flux, but the relationship of soil respiration and climate change was still obscurity. Most of soil respiration researches focus on template and tropical area, little was known that in subtropical area. Afforestation is one of solutions to mitigate CO2 increase and to sequestrate CO2 in <span class="hlt">tree</span> and soil. Therefore, the objective of this study is to clarify the relationship of <span class="hlt">tree</span> <span class="hlt">species</span> and soil respiration distribution in subtropical broad-leaves plantation in southern Taiwan. The research site located on southern Taiwan was sugarcane farm before 2002. The sugarcane was removed and fourteen broadleaved <span class="hlt">tree</span> <span class="hlt">species</span> were planted in 2002-2005. Sixteen plots (250m*250m) were set on 1 km2 area, each plot contained 4 subplots (170m2). The forest biomass (i.e. <span class="hlt">tree</span> height, DBH) understory biomass, litter, and soil C were measured and analyzed at 2011 to 2012. Soil respiration measurement was sampled in each subplot in each month. The soil belongs to Entisol with over 60% of sandstone. The soil pH is 5.5 with low base cations because of high sand percentage. Soil carbon storage showed significantly negative relationship with soil bulk density (p<0.001) in research site. The differences of distribution of live <span class="hlt">tree</span> C pool among 16 plots were affected by growth characteristic of <span class="hlt">tree</span> <span class="hlt">species</span>. Data showed that the accumulation amount of litterfall was highest in December to February and lowest in June. Different <span class="hlt">tree</span> <span class="hlt">species</span> planted in 16 plots, resulting in high spatial variation of litterfall amount. It also affected total amount of litterfall</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4748750','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4748750"><span id="translatedtitle">SimPhy: Phylogenomic Simulation of Gene, Locus, and <span class="hlt">Species</span> <span class="hlt">Trees</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Mallo, Diego; De Oliveira Martins, Leonardo; Posada, David</p> <p>2016-01-01</p> <p>We present a fast and flexible software package—SimPhy—for the simulation of multiple gene families evolving under incomplete lineage sorting, gene duplication and loss, horizontal gene transfer—all three potentially leading to <span class="hlt">species</span> <span class="hlt">tree</span>/gene <span class="hlt">tree</span> discordance—and gene conversion. SimPhy implements a hierarchical phylogenetic model in which the evolution of <span class="hlt">species</span>, locus, and gene <span class="hlt">trees</span> is governed by global and local parameters (e.g., genome-wide, <span class="hlt">species</span>-specific, locus-specific), that can be fixed or be sampled from a priori statistical distributions. SimPhy also incorporates comprehensive models of substitution rate variation among lineages (uncorrelated relaxed clocks) and the capability of simulating partitioned nucleotide, codon, and protein multilocus sequence alignments under a plethora of substitution models using the program INDELible. We validate SimPhy's output using theoretical expectations and other programs, and show that it scales extremely well with complex models and/or large <span class="hlt">trees</span>, being an order of magnitude faster than the most similar program (DLCoal-Sim). In addition, we demonstrate how SimPhy can be useful to understand interactions among different evolutionary processes, conducting a simulation study to characterize the systematic overestimation of the duplication time when using standard reconciliation methods. SimPhy is available at https://github.com/adamallo/SimPhy, where users can find the source code, precompiled executables, a detailed manual and example cases. PMID:26526427</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4814042','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4814042"><span id="translatedtitle">Mechanism Underlying the Spatial Pattern Formation of Dominant <span class="hlt">Tree</span> <span class="hlt">Species</span> in a Natural Secondary Forest</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Jia, Guodong; Yu, Xinxiao; Fan, Dengxing; Jia, Jianbo</p> <p>2016-01-01</p> <p>Studying the spatial pattern of plant <span class="hlt">species</span> may provide significant insights into processes and mechanisms that maintain stand stability. To better understand the dynamics of naturally regenerated secondary forests, univariate and bivariate Ripley’s L(r) functions were employed to evaluate intra-/interspecific relationships of four dominant <span class="hlt">tree</span> <span class="hlt">species</span> (Populus davidiana, Betula platyphylla, Larix gmelinii and Acer mono) and to distinguish the underlying mechanism of spatial distribution. The results showed that the distribution of soil, water and nutrients was not fragmented but presented clear gradients. An overall aggregated distribution existed at most distances. No correlation was found between the spatial pattern of soil conditions and that of <span class="hlt">trees</span>. Both positive and negative intra- and interspecific relationships were found between different DBH classes at various distances. Large <span class="hlt">trees</span> did not show systematic inhibition of the saplings. By contrast, the inhibition intensified as the height differences increased between the compared pairs. Except for Larix, universal inhibition of saplings by upper layer <span class="hlt">trees</span> occurred among other <span class="hlt">species</span>, and this reflected the vertical competition for light. Therefore, we believe that competition for light rather than soil nutrients underlies the mechanism driving the formation of stand spatial pattern in the rocky mountainous areas examined. PMID:27028757</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26526427','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26526427"><span id="translatedtitle">SimPhy: Phylogenomic Simulation of Gene, Locus, and <span class="hlt">Species</span> <span class="hlt">Trees</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mallo, Diego; De Oliveira Martins, Leonardo; Posada, David</p> <p>2016-03-01</p> <p>We present a fast and flexible software package--SimPhy--for the simulation of multiple gene families evolving under incomplete lineage sorting, gene duplication and loss, horizontal gene transfer--all three potentially leading to <span class="hlt">species</span> <span class="hlt">tree</span>/gene <span class="hlt">tree</span> discordance--and gene conversion. SimPhy implements a hierarchical phylogenetic model in which the evolution of <span class="hlt">species</span>, locus, and gene <span class="hlt">trees</span> is governed by global and local parameters (e.g., genome-wide, <span class="hlt">species</span>-specific, locus-specific), that can be fixed or be sampled from a priori statistical distributions. SimPhy also incorporates comprehensive models of substitution rate variation among lineages (uncorrelated relaxed clocks) and the capability of simulating partitioned nucleotide, codon, and protein multilocus sequence alignments under a plethora of substitution models using the program INDELible. We validate SimPhy's output using theoretical expectations and other programs, and show that it scales extremely well with complex models and/or large <span class="hlt">trees</span>, being an order of magnitude faster than the most similar program (DLCoal-Sim). In addition, we demonstrate how SimPhy can be useful to understand interactions among different evolutionary processes, conducting a simulation study to characterize the systematic overestimation of the duplication time when using standard reconciliation methods. SimPhy is available at https://github.com/adamallo/SimPhy, where users can find the source code, precompiled executables, a detailed manual and example cases. PMID:26526427</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27028757','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27028757"><span id="translatedtitle">Mechanism Underlying the Spatial Pattern Formation of Dominant <span class="hlt">Tree</span> <span class="hlt">Species</span> in a Natural Secondary Forest.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jia, Guodong; Yu, Xinxiao; Fan, Dengxing; Jia, Jianbo</p> <p>2016-01-01</p> <p>Studying the spatial pattern of plant <span class="hlt">species</span> may provide significant insights into processes and mechanisms that maintain stand stability. To better understand the dynamics of naturally regenerated secondary forests, univariate and bivariate Ripley's L(r) functions were employed to evaluate intra-/interspecific relationships of four dominant <span class="hlt">tree</span> <span class="hlt">species</span> (Populus davidiana, Betula platyphylla, Larix gmelinii and Acer mono) and to distinguish the underlying mechanism of spatial distribution. The results showed that the distribution of soil, water and nutrients was not fragmented but presented clear gradients. An overall aggregated distribution existed at most distances. No correlation was found between the spatial pattern of soil conditions and that of <span class="hlt">trees</span>. Both positive and negative intra- and interspecific relationships were found between different DBH classes at various distances. Large <span class="hlt">trees</span> did not show systematic inhibition of the saplings. By contrast, the inhibition intensified as the height differences increased between the compared pairs. Except for Larix, universal inhibition of saplings by upper layer <span class="hlt">trees</span> occurred among other <span class="hlt">species</span>, and this reflected the vertical competition for light. Therefore, we believe that competition for light rather than soil nutrients underlies the mechanism driving the formation of stand spatial pattern in the rocky mountainous areas examined. PMID:27028757</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26702442','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26702442"><span id="translatedtitle">Estimating the global conservation status of more than 15,000 Amazonian <span class="hlt">tree</span> <span class="hlt">species</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ter Steege, Hans; Pitman, Nigel C A; Killeen, Timothy J; Laurance, William F; Peres, Carlos A; Guevara, Juan Ernesto; Salomão, Rafael P; Castilho, Carolina V; Amaral, Iêda Leão; de Almeida Matos, Francisca Dionízia; de Souza Coelho, Luiz; Magnusson, William E; Phillips, Oliver L; de Andrade Lima Filho, Diogenes; de Jesus Veiga Carim, Marcelo; Irume, Mariana Victória; Martins, Maria Pires; Molino, Jean-François; Sabatier, Daniel; Wittmann, Florian; López, Dairon Cárdenas; da Silva Guimarães, José Renan; Mendoza, Abel Monteagudo; Vargas, Percy Núñez; Manzatto, Angelo Gilberto; Reis, Neidiane Farias Costa; Terborgh, John; Casula, Katia Regina; Montero, Juan Carlos; Feldpausch, Ted R; Honorio Coronado, Euridice N; Montoya, Alvaro Javier Duque; Zartman, Charles Eugene; Mostacedo, Bonifacio; Vasquez, Rodolfo; Assis, Rafael L; Medeiros, Marcelo Brilhante; Simon, Marcelo Fragomeni; Andrade, Ana; Camargo, José Luís; Laurance, Susan G W; Nascimento, Henrique Eduardo Mendonça; Marimon, Beatriz S; Marimon, Ben-Hur; Costa, Flávia; Targhetta, Natalia; Vieira, Ima Célia Guimarães; Brienen, Roel; Castellanos, Hernán; Duivenvoorden, Joost F; Mogollón, Hugo F; Piedade, Maria Teresa Fernandez; Aymard C, Gerardo A; Comiskey, James A; Damasco, Gabriel; Dávila, Nállarett; García-Villacorta, Roosevelt; Diaz, Pablo Roberto Stevenson; Vincentini, Alberto; Emilio, Thaise; Levis, Carolina; Schietti, Juliana; Souza, Priscila; Alonso, Alfonso; Dallmeier, Francisco; Ferreira, Leandro Valle; Neill, David; Araujo-Murakami, Alejandro; Arroyo, Luzmila; Carvalho, Fernanda Antunes; Souza, Fernanda Coelho; do Amaral, Dário Dantas; Gribel, Rogerio; Luize, Bruno Garcia; Pansonato, Marcelo Petrati; Venticinque, Eduardo; Fine, Paul; Toledo, Marisol; Baraloto, Chris; Cerón, Carlos; Engel, Julien; Henkel, Terry W; Jimenez, Eliana M; Maas, Paul; Mora, Maria Cristina Peñuela; Petronelli, Pascal; Revilla, Juan David Cardenas; Silveira, Marcos; Stropp, Juliana; Thomas-Caesar, Raquel; Baker, Tim R; Daly, Doug; Paredes, Marcos Ríos; da Silva, Naara Ferreira; Fuentes, Alfredo; Jørgensen, Peter Møller; Schöngart, Jochen; Silman, Miles R; Arboleda, Nicolás Castaño; Cintra, Bruno Barçante Ladvocat; Valverde, Fernando Cornejo; Di Fiore, Anthony; Phillips, Juan Fernando; van Andel, Tinde R; von Hildebrand, Patricio; Barbosa, Edelcilio Marques; de Matos Bonates, Luiz Carlos; de Castro, Deborah; de Sousa Farias, Emanuelle; Gonzales, Therany; Guillaumet, Jean-Louis; Hoffman, Bruce; Malhi, Yadvinder; de Andrade Miranda, Ires Paula; Prieto, Adriana; Rudas, Agustín; Ruschell, Ademir R; Silva, Natalino; Vela, César I A; Vos, Vincent A; Zent, Eglée L; Zent, Stanford; Cano, Angela; Nascimento, Marcelo Trindade; Oliveira, Alexandre A; Ramirez-Angulo, Hirma; Ramos, José Ferreira; Sierra, Rodrigo; Tirado, Milton; Medina, Maria Natalia Umaña; van der Heijden, Geertje; Torre, Emilio Vilanova; Vriesendorp, Corine; Wang, Ophelia; Young, Kenneth R; Baider, Claudia; Balslev, Henrik; de Castro, Natalia; Farfan-Rios, William; Ferreira, Cid; Mendoza, Casimiro; Mesones, Italo; Torres-Lezama, Armando; Giraldo, Ligia Estela Urrego; Villarroel, Daniel; Zagt, Roderick; Alexiades, Miguel N; Garcia-Cabrera, Karina; Hernandez, Lionel; Huamantupa-Chuquimaco, Isau; Milliken, William; Cuenca, Walter Palacios; Pansini, Susamar; Pauletto, Daniela; Arevalo, Freddy Ramirez; Sampaio, Adeilza Felipe; Valderrama Sandoval, Elvis H; Gamarra, Luis Valenzuela</p> <p>2015-11-01</p> <p>Estimates of extinction risk for Amazonian plant and animal <span class="hlt">species</span> are rare and not often incorporated into land-use policy and conservation planning. We overlay spatial distribution models with historical and projected deforestation to show that at least 36% and up to 57% of all Amazonian <span class="hlt">tree</span> <span class="hlt">species</span> are likely to qualify as globally threatened under International Union for Conservation of Nature (IUCN) Red List criteria. If confirmed, these results would increase the number of threatened plant <span class="hlt">species</span> on Earth by 22%. We show that the trends observed in Amazonia apply to <span class="hlt">trees</span> throughout the tropics, and we predict that most of the world's >40,000 tropical <span class="hlt">tree</span> <span class="hlt">species</span> now qualify as globally threatened. A gap analysis suggests that existing Amazonian protected areas and indigenous territories will protect viable populations of most threatened <span class="hlt">species</span> if these areas suffer no further degradation, highlighting the key roles that protected areas, indigenous peoples, and improved governance can play in preventing large-scale extinctions in the tropics in this century. PMID:26702442</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23360009','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23360009"><span id="translatedtitle">Floristic diversity of regenerated <span class="hlt">tree</span> <span class="hlt">species</span> in Dipterocarp forests in Western Ghats of Karnataka, India.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Prasad, A G Devi; Al-Sagheer, Nageeb A</p> <p>2012-07-01</p> <p>The research was focused on exploring the structure, diversity and form of regeneration process of the Dipterocarp forests in Western Ghats in relation to environmental factors. Eight populations in the distribution range of Dipterocarp forests were selected. In each population 32 plots of 2mx2m were laid down randomly. Atotal of 1243 seedlings < or = 10 cm dbh (diameter at breast height) belonging to 99 <span class="hlt">species</span> and 48 families were recorded. The number of regenerated <span class="hlt">tree</span> <span class="hlt">species</span> was found to be high in the populations of Mudigere (40), Sakleshpura (40) and Makuta (39), which are characterized by favorable locality factors and lower disturbances. The highest similarity index in <span class="hlt">species</span> composition was recorded between the populations of Sampaje in Kodagu district and Gundya in Dakshina Kannada (60%) whereas the lowest similarity index was observed between the population of Sringeri in Chikmagalore and Sampaje (53%) and Gundya and Makuta (35%) in Kodagu district. Dipterocarpus indicus was found to be dominant among the regenerated <span class="hlt">tree</span> <span class="hlt">species</span> in all the sites studied except Gundy and Sampaje. The frequencies of regeneration classes (seedlings, saplings, poles and adult <span class="hlt">trees</span>) were shaped as inverse J curve indicating the normal regeneration pattern under the present disturbance. The average disturbance of litter collection, grazing, fire, weeds and canopy opening were significant among different populations (p < or = 0.05). Negative correlation was observed between disturbance and <span class="hlt">species</span> richness, number of individuals and density. PMID:23360009</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4681336','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4681336"><span id="translatedtitle">Estimating the global conservation status of more than 15,000 Amazonian <span class="hlt">tree</span> <span class="hlt">species</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>ter Steege, Hans; Pitman, Nigel C. A.; Killeen, Timothy J.; Laurance, William F.; Peres, Carlos A.; Guevara, Juan Ernesto; Salomão, Rafael P.; Castilho, Carolina V.; Amaral, Iêda Leão; de Almeida Matos, Francisca Dionízia; de Souza Coelho, Luiz; Magnusson, William E.; Phillips, Oliver L.; de Andrade Lima Filho, Diogenes; de Jesus Veiga Carim, Marcelo; Irume, Mariana Victória; Martins, Maria Pires; Molino, Jean-François; Sabatier, Daniel; Wittmann, Florian; López, Dairon Cárdenas; da Silva Guimarães, José Renan; Mendoza, Abel Monteagudo; Vargas, Percy Núñez; Manzatto, Angelo Gilberto; Reis, Neidiane Farias Costa; Terborgh, John; Casula, Katia Regina; Montero, Juan Carlos; Feldpausch, Ted R.; Honorio Coronado, Euridice N.; Montoya, Alvaro Javier Duque; Zartman, Charles Eugene; Mostacedo, Bonifacio; Vasquez, Rodolfo; Assis, Rafael L.; Medeiros, Marcelo Brilhante; Simon, Marcelo Fragomeni; Andrade, Ana; Camargo, José Luís; Laurance, Susan G. W.; Nascimento, Henrique Eduardo Mendonça; Marimon, Beatriz S.; Marimon, Ben-Hur; Costa, Flávia; Targhetta, Natalia; Vieira, Ima Célia Guimarães; Brienen, Roel; Castellanos, Hernán; Duivenvoorden, Joost F.; Mogollón, Hugo F.; Piedade, Maria Teresa Fernandez; Aymard C., Gerardo A.; Comiskey, James A.; Damasco, Gabriel; Dávila, Nállarett; García-Villacorta, Roosevelt; Diaz, Pablo Roberto Stevenson; Vincentini, Alberto; Emilio, Thaise; Levis, Carolina; Schietti, Juliana; Souza, Priscila; Alonso, Alfonso; Dallmeier, Francisco; Ferreira, Leandro Valle; Neill, David; Araujo-Murakami, Alejandro; Arroyo, Luzmila; Carvalho, Fernanda Antunes; Souza, Fernanda Coelho; do Amaral, Dário Dantas; Gribel, Rogerio; Luize, Bruno Garcia; Pansonato, Marcelo Petrati; Venticinque, Eduardo; Fine, Paul; Toledo, Marisol; Baraloto, Chris; Cerón, Carlos; Engel, Julien; Henkel, Terry W.; Jimenez, Eliana M.; Maas, Paul; Mora, Maria Cristina Peñuela; Petronelli, Pascal; Revilla, Juan David Cardenas; Silveira, Marcos; Stropp, Juliana; Thomas-Caesar, Raquel; Baker, Tim R.; Daly, Doug; Paredes, Marcos Ríos; da Silva, Naara Ferreira; Fuentes, Alfredo; Jørgensen, Peter Møller; Schöngart, Jochen; Silman, Miles R.; Arboleda, Nicolás Castaño; Cintra, Bruno Barçante Ladvocat; Valverde, Fernando Cornejo; Di Fiore, Anthony; Phillips, Juan Fernando; van Andel, Tinde R.; von Hildebrand, Patricio; Barbosa, Edelcilio Marques; de Matos Bonates, Luiz Carlos; de Castro, Deborah; de Sousa Farias, Emanuelle; Gonzales, Therany; Guillaumet, Jean-Louis; Hoffman, Bruce; Malhi, Yadvinder; de Andrade Miranda, Ires Paula; Prieto, Adriana; Rudas, Agustín; Ruschell, Ademir R.; Silva, Natalino; Vela, César I. A.; Vos, Vincent A.; Zent, Eglée L.; Zent, Stanford; Cano, Angela; Nascimento, Marcelo Trindade; Oliveira, Alexandre A.; Ramirez-Angulo, Hirma; Ramos, José Ferreira; Sierra, Rodrigo; Tirado, Milton; Medina, Maria Natalia Umaña; van der Heijden, Geertje; Torre, Emilio Vilanova; Vriesendorp, Corine; Wang, Ophelia; Young, Kenneth R.; Baider, Claudia; Balslev, Henrik; de Castro, Natalia; Farfan-Rios, William; Ferreira, Cid; Mendoza, Casimiro; Mesones, Italo; Torres-Lezama, Armando; Giraldo, Ligia Estela Urrego; Villarroel, Daniel; Zagt, Roderick; Alexiades, Miguel N.; Garcia-Cabrera, Karina; Hernandez, Lionel; Huamantupa-Chuquimaco, Isau; Milliken, William; Cuenca, Walter Palacios; Pansini, Susamar; Pauletto, Daniela; Arevalo, Freddy Ramirez; Sampaio, Adeilza Felipe; Valderrama Sandoval, Elvis H.; Gamarra, Luis Valenzuela</p> <p>2015-01-01</p> <p>Estimates of extinction risk for Amazonian plant and animal <span class="hlt">species</span> are rare and not often incorporated into land-use policy and conservation planning. We overlay spatial distribution models with historical and projected deforestation to show that at least 36% and up to 57% of all Amazonian <span class="hlt">tree</span> <span class="hlt">species</span> are likely to qualify as globally threatened under International Union for Conservation of Nature (IUCN) Red List criteria. If confirmed, these results would increase the number of threatened plant <span class="hlt">species</span> on Earth by 22%. We show that the trends observed in Amazonia apply to <span class="hlt">trees</span> throughout the tropics, and we predict that most of the world’s >40,000 tropical <span class="hlt">tree</span> <span class="hlt">species</span> now qualify as globally threatened. A gap analysis suggests that existing Amazonian protected areas and indigenous territories will protect viable populations of most threatened <span class="hlt">species</span> if these areas suffer no further degradation, highlighting the key roles that protected areas, indigenous peoples, and improved governance can play in preventing large-scale extinctions in the tropics in this century. PMID:26702442</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4971193','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4971193"><span id="translatedtitle">The Trichoptera barcode initiative: a strategy for generating a <span class="hlt">species</span>-level <span class="hlt">Tree</span> of Life</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Frandsen, Paul B.; Holzenthal, Ralph W.; Beet, Clare R.; Bennett, Kristi R.; Blahnik, Roger J.; Bonada, Núria; Cartwright, David; Chuluunbat, Suvdtsetseg; Cocks, Graeme V.; Collins, Gemma E.; deWaard, Jeremy; Dean, John; Flint, Oliver S.; Hausmann, Axel; Hendrich, Lars; Hess, Monika; Hogg, Ian D.; Kondratieff, Boris C.; Malicky, Hans; Milton, Megan A.; Morinière, Jérôme; Morse, John C.; Mwangi, François Ngera; Pauls, Steffen U.; Gonzalez, María Razo; Rinne, Aki; Robinson, Jason L.; Salokannel, Juha; Shackleton, Michael; Smith, Brian; Stamatakis, Alexandros; StClair, Ros; Thomas, Jessica A.; Zamora-Muñoz, Carmen; Ziesmann, Tanja</p> <p>2016-01-01</p> <p>DNA barcoding was intended as a means to provide <span class="hlt">species</span>-level identifications through associating DNA sequences from unknown specimens to those from curated reference specimens. Although barcodes were not designed for phylogenetics, they can be beneficial to the completion of the <span class="hlt">Tree</span> of Life. The barcode database for Trichoptera is relatively comprehensive, with data from every family, approximately two-thirds of the genera, and one-third of the described <span class="hlt">species</span>. Most Trichoptera, as with most of life's <span class="hlt">species</span>, have never been subjected to any formal phylogenetic analysis. Here, we present a phylogeny with over 16 000 unique haplotypes as a working hypothesis that can be updated as our estimates improve. We suggest a strategy of implementing constrained <span class="hlt">tree</span> searches, which allow larger datasets to dictate the backbone phylogeny, while the barcode data fill out the tips of the <span class="hlt">tree</span>. We also discuss how this phylogeny could be used to focus taxonomic attention on ambiguous <span class="hlt">species</span> boundaries and hidden biodiversity. We suggest that systematists continue to differentiate between ‘Barcode Index Numbers’ (BINs) and ‘species’ that have been formally described. Each has utility, but they are not synonyms. We highlight examples of integrative taxonomy, using both barcodes and morphology for <span class="hlt">species</span> description. This article is part of the themed issue ‘From DNA barcodes to biomes’. PMID:27481793</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/927777','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/927777"><span id="translatedtitle">Managing Commercial <span class="hlt">Tree</span> <span class="hlt">Species</span> for Timber Production and Carbon Sequestration: Management Guidelines and Financial Returns</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gary D. Kronrad</p> <p>2006-09-19</p> <p>A carbon credit market is developing in the United States. Information is needed by buyers and sellers of carbon credits so that the market functions equitably and efficiently. Analyses have been conducted to determine the optimal forest management regime to employ for each of the major commercial <span class="hlt">tree</span> <span class="hlt">species</span> so that profitability of timber production only or the combination of timber production and carbon sequestration is maximized. Because the potential of a forest ecosystem to sequester carbon depends on the <span class="hlt">tree</span> <span class="hlt">species</span>, site quality and management regimes utilized, analyses have determined how to optimize carbon sequestration by determining how to optimally manage each <span class="hlt">species</span>, given a range of site qualities, discount rates, prices of carbon credits and other economic variables. The effects of a carbon credit market on the method and profitability of forest management, the cost of sequestering carbon, the amount of carbon that can be sequestered, and the amount of timber products produced has been determined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4255775','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4255775"><span id="translatedtitle">Multispecies Coalescent Analysis of the Early Diversification of Neotropical Primates: Phylogenetic Inference under Strong Gene <span class="hlt">Trees/Species</span> <span class="hlt">Tree</span> Conflict</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Schrago, Carlos G.; Menezes, Albert N.; Furtado, Carolina; Bonvicino, Cibele R.; Seuanez, Hector N.</p> <p>2014-01-01</p> <p>Neotropical primates (NP) are presently distributed in the New World from Mexico to northern Argentina, comprising three large families, Cebidae, Atelidae, and Pitheciidae, consequently to their diversification following their separation from Old World anthropoids near the Eocene/Oligocene boundary, some 40 Ma. The evolution of NP has been intensively investigated in the last decade by studies focusing on their phylogeny and timescale. However, despite major efforts, the phylogenetic relationship between these three major clades and the age of their last common ancestor are still controversial because these inferences were based on limited numbers of loci and dating analyses that did not consider the evolutionary variation associated with the distribution of gene <span class="hlt">trees</span> within the proposed phylogenies. We show, by multispecies coalescent analyses of selected genome segments, spanning along 92,496,904 bp that the early diversification of extant NP was marked by a 2-fold increase of their effective population size and that Atelids and Cebids are more closely related respective to Pitheciids. The molecular phylogeny of NP has been difficult to solve because of population-level phenomena at the early evolution of the lineage. The association of evolutionary variation with the distribution of gene <span class="hlt">trees</span> within proposed phylogenies is crucial for distinguishing the mean genetic divergence between <span class="hlt">species</span> (the mean coalescent time between loci) from speciation time. This approach, based on extensive genomic data provided by new generation DNA sequencing, provides more accurate reconstructions of phylogenies and timescales for all organisms. PMID:25377940</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014BGeo...11.1649L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014BGeo...11.1649L"><span id="translatedtitle">Soil greenhouse gas fluxes from different <span class="hlt">tree</span> <span class="hlt">species</span> on Taihang Mountain, North China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, X. P.; Zhang, W. J.; Hu, C. S.; Tang, X. G.</p> <p>2014-03-01</p> <p>The objectives of this study were to investigate seasonal variation of greenhouse gas fluxes from soils on sites dominated by plantation (Robinia pseudoacacia, Punica granatum, and Ziziphus jujube) and natural regenerated forests (Vitex negundo var. heterophylla, Leptodermis oblonga, and Bothriochloa ischcemum), and to identify how <span class="hlt">tree</span> <span class="hlt">species</span>, litter exclusion, and soil properties (soil temperature, soil moisture, soil organic carbon, total N, soil bulk density, and soil pH) explained the temporal and spatial variation in soil greenhouse gas fluxes. Fluxes of greenhouse gases were measured using static chamber and gas chromatography techniques. Six static chambers were randomly installed in each <span class="hlt">tree</span> <span class="hlt">species</span>. Three chambers were randomly designated to measure the impacts of surface litter exclusion, and the remaining three were used as a control. Field measurements were conducted biweekly from May 2010 to April 2012. Soil CO2 emissions from all <span class="hlt">tree</span> <span class="hlt">species</span> were significantly affected by soil temperature, soil moisture, and their interaction. Driven by the seasonality of temperature and precipitation, soil CO2 emissions demonstrated a clear seasonal pattern, with fluxes significantly higher during the rainy season than during the dry season. Soil CH4 and N2O fluxes were not significantly correlated with soil temperature, soil moisture, or their interaction, and no significant seasonal differences were detected. Soil organic carbon and total N were significantly positively correlated with CO2 and N2O fluxes. Soil bulk density was significantly negatively correlated with CO2 and N2O fluxes. Soil pH was not correlated with CO2 and N2O emissions. Soil CH4 fluxes did not display pronounced dependency on soil organic carbon, total N, soil bulk density, and soil pH. Removal of surface litter significantly decreased in CO2 emissions and CH4 uptakes. Soils in six <span class="hlt">tree</span> <span class="hlt">species</span> acted as sinks for atmospheric CH4. With the exception of Ziziphus jujube, soils in all <span class="hlt">tree</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.B53F..04M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.B53F..04M"><span id="translatedtitle"><span class="hlt">Tree</span> <span class="hlt">Species</span> Linked to Large Differences in Ecosystem Carbon Distribution in the Boreal Forest of Alaska</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Melvin, A. M.; Mack, M. C.; Johnstone, J. F.; Schuur, E. A. G.; Genet, H.; McGuire, A. D.</p> <p>2014-12-01</p> <p>In the boreal forest of Alaska, increased fire severity associated with climate change is altering plant-soil-microbial feedbacks and ecosystem carbon (C) dynamics. The boreal landscape has historically been dominated by black spruce (Picea mariana), a <span class="hlt">tree</span> <span class="hlt">species</span> associated with slow C turnover and large soil organic matter (SOM) accumulation. Historically, low severity fires have led to black spruce regeneration post-fire, thereby maintaining slow C cycling rates and large SOM pools. In recent decades however, an increase in high severity fires has led to greater consumption of the soil organic layer (SOL) during fire and subsequent establishment of deciduous <span class="hlt">tree</span> <span class="hlt">species</span> in areas previously dominated by black spruce. This shift to a more deciduous dominated landscape has many implications for ecosystem structure and function, as well as feedbacks to global C cycling. To improve our understanding of how boreal <span class="hlt">tree</span> <span class="hlt">species</span> affect C cycling, we quantified above- and belowground C stocks and fluxes in adjacent, mid-successional stands of black spruce and Alaska paper birch (Betula neoalaskana) that established following a 1958 fire near Fairbanks, Alaska. Although total ecosystem C pools (aboveground live <span class="hlt">tree</span> biomass + dead wood + SOL + top 10 cm of mineral soil) were similar for the two stand types, the distribution of C among pools was markedly different. In black spruce, 78% of measured C was found in soil pools, primarily in the SOL, where spruce contained twice the C stored in paper birch (4.8 ± 0.3 vs. 2.4 ± 0.1 kg C m-2). In contrast, aboveground biomass dominated ecosystem C pools in birch forest (6.0 ± 0.3 vs. 2.5 ± 0.2 kg C m-2 in birch and spruce, respectively). Our findings suggest that <span class="hlt">tree</span> <span class="hlt">species</span> exert a strong influence over plant-soil-microbial feedbacks and may have long-term effects on ecosystem C sequestration and storage that feedback to the climate system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24486469','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24486469"><span id="translatedtitle">Converting probabilistic <span class="hlt">tree</span> <span class="hlt">species</span> range shift projections into meaningful classes for management.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hanewinkel, Marc; Cullmann, Dominik A; Michiels, Hans-Gerd; Kändler, Gerald</p> <p>2014-02-15</p> <p>The paper deals with the management problem how to decide on <span class="hlt">tree</span> <span class="hlt">species</span> suitability under changing environmental conditions. It presents an algorithm that classifies the output of a range shift model for major <span class="hlt">tree</span> <span class="hlt">species</span> in Europe into multiple classes that can be linked to qualities characterizing the ecological niche of the <span class="hlt">species</span>. The classes: i) Core distribution area, ii) Extended distribution area, iii) Occasional occurrence area, and iv) No occurrence area are first theoretically developed and then statistically described. The classes are interpreted from an ecological point of view using criteria like population structure, competitive strength, site spectrum and vulnerability to biotic hazards. The functioning of the algorithm is demonstrated using the example of a generalized linear model that was fitted to a pan-European dataset of presence/absence of major <span class="hlt">tree</span> <span class="hlt">species</span> with downscaled climate data from a General Circulation Model (GCM). Applications of the algorithm to <span class="hlt">tree</span> <span class="hlt">species</span> suitability classification on a European and regional level are shown. The thresholds that are used by the algorithm are precision-based and include Cohen's Kappa. A validation of the algorithm using an independent dataset of the German National Forest Inventory shows good accordance of the statistically derived classes with ecological traits for Norway spruce, while the differentiation especially between core and extended distribution for European beech that is in the centre of its natural range in this area is less accurate. We hypothesize that for <span class="hlt">species</span> in the core of their range regional factors like forest history superimpose climatic factors. Problems of uncertainty issued from potentially applying a multitude of modelling approaches and/or climate realizations within the range shift model are discussed and a way to deal with the uncertainty by revealing the underlying attitude towards risk of the decision maker is proposed. PMID:24486469</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27265248','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27265248"><span id="translatedtitle">Taxonomic and ecological relevance of the chlorophyll a fluorescence signature of <span class="hlt">tree</span> <span class="hlt">species</span> in mixed European forests.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pollastrini, Martina; Holland, Vera; Brüggemann, Wolfgang; Bruelheide, Helge; Dănilă, Iulian; Jaroszewicz, Bogdan; Valladares, Fernando; Bussotti, Filippo</p> <p>2016-10-01</p> <p>The variability of chlorophyll a fluorescence (ChlF) parameters of forest <span class="hlt">tree</span> <span class="hlt">species</span> was investigated in 209 stands belonging to six European forests, from Mediterranean to boreal regions. The modifying role of environmental factors, forest structure and <span class="hlt">tree</span> diversity (<span class="hlt">species</span> richness and composition) on ChlF signature was analysed. At the European level, conifers showed higher potential performance than broadleaf <span class="hlt">species</span>. Forests in central Europe performed better than those in Mediterranean and boreal regions. At the site level, homogeneous clusters of <span class="hlt">tree</span> <span class="hlt">species</span> were identified by means of a principal component analysis (PCA) of ChlF parameters. The discrimination of the clusters of <span class="hlt">species</span> was influenced by their taxonomic position and ecological characteristics. The <span class="hlt">species</span> richness influenced the <span class="hlt">tree</span> ChlF properties in different ways depending on <span class="hlt">tree</span> <span class="hlt">species</span> and site. <span class="hlt">Tree</span> <span class="hlt">species</span> and site also affected the relationships between ChlF parameters and other plant functional traits (specific leaf area, leaf nitrogen content, light-saturated photosynthesis, wood density, leaf carbon isotope composition). The assessment of the photosynthetic properties of <span class="hlt">tree</span> <span class="hlt">species</span>, by means of ChlF parameters, in relation to their functional traits, is a relevant issue for studies in forest ecology. The connections of data from field surveys with remotely assessed parameters must be carefully explored. PMID:27265248</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26865971','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26865971"><span id="translatedtitle"><span class="hlt">Tree</span> <span class="hlt">species</span> richness decreases while <span class="hlt">species</span> evenness increases with disturbance frequency in a natural boreal forest landscape.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yeboah, Daniel; Chen, Han Y H; Kingston, Steve</p> <p>2016-02-01</p> <p>Understanding <span class="hlt">species</span> diversity and disturbance relationships is important for biodiversity conservation in disturbance-driven boreal forests. <span class="hlt">Species</span> richness and evenness may respond differently with stand development following fire. Furthermore, few studies have simultaneously accounted for the influences of climate and local site conditions on <span class="hlt">species</span> diversity. Using forest inventory data, we examined the relationships between <span class="hlt">species</span> richness, Shannon's index, evenness, and time since last stand-replacing fire (TSF) in a large landscape of disturbance-driven boreal forest. TSF has negative effect on <span class="hlt">species</span> richness and Shannon's index, and a positive effect on <span class="hlt">species</span> evenness. Path analysis revealed that the environmental variables affect richness and Shannon's index only through their effects on TSF while affecting evenness directly as well as through their effects on TSF. Synthesis and applications. Our results demonstrate that <span class="hlt">species</span> richness and Shannon's index decrease while <span class="hlt">species</span> evenness increases with TSF in a boreal forest landscape. Furthermore, we show that disturbance frequency, local site conditions, and climate simultaneously influence <span class="hlt">tree</span> <span class="hlt">species</span> diversity through complex direct and indirect effects in the studied boreal forest. PMID:26865971</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70123146','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70123146"><span id="translatedtitle">The brown <span class="hlt">tree</span> snake, an introduced pest <span class="hlt">species</span> in the central Pacific Islands</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Fritts, Thomas H.; Rodda, Gordon H.</p> <p>1989-01-01</p> <p>The reproduction of endangered Mariana crows (Corvus kubaryi) is intensively monitored, nests are protected, and (when necessary) eggs or young are moved to the safety of lab conditions until they are less vulnerable to the threats in natural habitats. Barriers on <span class="hlt">tree</span> trunks and judicious pruning of adjacent <span class="hlt">trees</span> are used in attempts to exclude snakes from nest <span class="hlt">trees</span>. Two birds unique to Guam--the Micronesian kingfisher (Halcyon cinnamomina cinnamomina) and Guam rail (Gallirallus owstoni)-- are maintained at captive propagation facilities on Guam and in mainland zoos. Studies of these and other <span class="hlt">species</span>, in captivity and on nearby islands, are underway to bolster our biological understanding of their behavior, reproduction, habitat use, and population biology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24337711','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24337711"><span id="translatedtitle"><span class="hlt">Tree</span> <span class="hlt">species</span> from different functional groups respond differently to environmental changes during establishment.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Barbosa, Eduardo R M; van Langevelde, Frank; Tomlinson, Kyle W; Carvalheiro, Luísa G; Kirkman, Kevin; de Bie, Steven; Prins, Herbert H T</p> <p>2014-04-01</p> <p>Savanna plant communities change considerably across time and space. The processes driving savanna plant <span class="hlt">species</span> diversity, coexistence and turnover along environmental gradients are still unclear. Understanding how <span class="hlt">species</span> respond differently to varying environmental conditions during the seedling stage, a critical stage for plant population dynamics, is needed to explain the current composition of plant communities and to enable us to predict their responses to future environmental changes. Here we investigate whether seedling response to changes in resource availability, and to competition with grass, varied between two functional groups of African savanna <span class="hlt">trees</span>: <span class="hlt">species</span> with small leaves, spines and N-fixing associations (fine-leaved <span class="hlt">species</span>), and <span class="hlt">species</span> with broad leaves, no spines, and lacking N-fixing associations (broad-leaved <span class="hlt">species</span>). We show that while <span class="hlt">tree</span> <span class="hlt">species</span> were strongly suppressed by grass, the effect of resource availability on seedling performance varied considerably between the two functional groups. Nutrient inputs increased stem length only of broad-leaved <span class="hlt">species</span> and only under an even watering treatment. Low light conditions benefited mostly broad-leaved <span class="hlt">species</span>' growth. Savannas are susceptible to ongoing global environment changes. Our results suggest that an increase in woody cover is only likely to occur in savannas if grass cover is strongly suppressed (e.g. by fire or overgrazing). However, if woody cover does increase, broad-leaved <span class="hlt">species</span> will benefit most from the resulting shaded environments, potentially leading to an expansion of the distribution of these <span class="hlt">species</span>. Eutrophication and changes in rainfall patterns may also affect the balance between fine- and broad-leaved <span class="hlt">species</span>. PMID:24337711</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3419707','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3419707"><span id="translatedtitle">Geological Substrates Shape <span class="hlt">Tree</span> <span class="hlt">Species</span> and Trait Distributions in African Moist Forests</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Fayolle, Adeline; Engelbrecht, Bettina; Freycon, Vincent; Mortier, Frédéric; Swaine, Michael; Réjou-Méchain, Maxime; Doucet, Jean-Louis; Fauvet, Nicolas; Cornu, Guillaume; Gourlet-Fleury, Sylvie</p> <p>2012-01-01</p> <p>Background Understanding the factors that shape the distribution of tropical <span class="hlt">tree</span> <span class="hlt">species</span> at large scales is a central issue in ecology, conservation and forest management. The aims of this study were to (i) assess the importance of environmental factors relative to historical factors for <span class="hlt">tree</span> <span class="hlt">species</span> distributions in the semi-evergreen forests of the northern Congo basin; and to (ii) identify potential mechanisms explaining distribution patterns through a trait-based approach. Methodology/Principal Findings We analyzed the distribution patterns of 31 common <span class="hlt">tree</span> <span class="hlt">species</span> in an area of more than 700,000 km2 spanning the borders of Cameroon, the Central African Republic, and the Republic of Congo using forest inventory data from 56,445 0.5-ha plots. Spatial variation of environmental (climate, topography and geology) and historical factors (human disturbance) were quantified from maps and satellite records. Four key functional traits (leaf phenology, shade tolerance, wood density, and maximum growth rate) were extracted from the literature. The geological substrate was of major importance for the distribution of the focal <span class="hlt">species</span>, while climate and past human disturbances had a significant but lesser impact. <span class="hlt">Species</span> distribution patterns were significantly related to functional traits. <span class="hlt">Species</span> associated with sandy soils typical of sandstone and alluvium were characterized by slow growth rates, shade tolerance, evergreen leaves, and high wood density, traits allowing persistence on resource-poor soils. In contrast, fast-growing pioneer <span class="hlt">species</span> rarely occurred on sandy soils, except for Lophira alata. Conclusions/Significance The results indicate strong environmental filtering due to differential soil resource availability across geological substrates. Additionally, long-term human disturbances in resource-rich areas may have accentuated the observed patterns of <span class="hlt">species</span> and trait distributions. Trait differences across geological substrates imply pronounced</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21445684','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21445684"><span id="translatedtitle">Comparative hydraulic architecture of tropical <span class="hlt">tree</span> <span class="hlt">species</span> representing a range of successional stages and wood density.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>McCulloh, Katherine A; Meinzer, Frederick C; Sperry, John S; Lachenbruch, Barbara; Voelker, Steven L; Woodruff, David R; Domec, Jean-Christophe</p> <p>2011-09-01</p> <p>Plant hydraulic architecture (PHA) has been linked to water transport sufficiency, photosynthetic rates, growth form and attendant carbon allocation. Despite its influence on traits central to conferring an overall competitive advantage in a given environment, few studies have examined whether key aspects of PHA are indicative of successional stage, especially within mature individuals. While it is well established that wood density (WD) tends to be lower in early versus late successional <span class="hlt">tree</span> <span class="hlt">species</span>, and that WD can influence other aspects of PHA, the interaction of WD, successional stage and the consequent implications for PHA have not been sufficiently explored. Here, we studied differences in PHA at the scales of wood anatomy to whole-<span class="hlt">tree</span> hydraulic conductance in <span class="hlt">species</span> in early versus late successional Panamanian tropical forests. Although the trunk WD was indistinguishable between the successional groups, the branch WD was lower in the early successional <span class="hlt">species</span>. Across all <span class="hlt">species</span>, WD correlated negatively with vessel diameter and positively with vessel packing density. The ratio of branch:trunk vessel diameter, branch sap flux and whole-<span class="hlt">tree</span> leaf-specific conductance scaled negatively with branch WD across <span class="hlt">species</span>. Pioneer <span class="hlt">species</span> showed greater sap flux in branches than in trunks and a greater leaf-specific hydraulic conductance, suggesting that pioneer <span class="hlt">species</span> can move greater quantities of water at a given tension gradient. In combination with the greater water storage capacitance associated with lower WD, these results suggest these pioneer <span class="hlt">species</span> can save on the carbon expenditure needed to build safer xylem and instead allow more carbon to be allocated to rapid growth. PMID:21445684</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24488084','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24488084"><span id="translatedtitle">The right <span class="hlt">tree</span> for the job? perceptions of <span class="hlt">species</span> suitability for the provision of ecosystem services.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Smaill, Simeon J; Bayne, Karen M; Coker, Graham W R; Paul, Thomas S H; Clinton, Peter W</p> <p>2014-04-01</p> <p>Stakeholders in plantation forestry are increasingly aware of the importance of the ecosystem services and non-market values associated with forests. In New Zealand, there is significant interest in establishing <span class="hlt">species</span> other than Pinus radiata D. Don (the dominant plantation <span class="hlt">species</span>) in the belief that alternative <span class="hlt">species</span> are better suited to deliver these services. Significant risk is associated with this position as there is little objective data to support these views. To identify which <span class="hlt">species</span> were likely to be planted to deliver ecosystem services, a survey was distributed to examine stakeholder perceptions. Stakeholders were asked which of 15 <span class="hlt">tree</span> attributes contributed to the provision of five ecosystem services (amenity value, bioenergy production, carbon capture, the diversity of native habitat, and erosion control/water quality) and to identify which of 22 candidate <span class="hlt">tree</span> <span class="hlt">species</span> possessed those attributes. These data were combined to identify the <span class="hlt">species</span> perceived most suitable for the delivery of each ecosystem service. Sequoia sempervirens (D.Don) Endl. closely matched the stakeholder derived ideotypes associated with all five ecosystem services. Comparisons to data from growth, physiological and ecological studies demonstrated that many of the opinions held by stakeholders were inaccurate, leading to erroneous assumptions regarding the suitability of most candidate <span class="hlt">species</span>. Stakeholder perceptions substantially influence <span class="hlt">tree</span> <span class="hlt">species</span> selection, and plantations established on the basis of inaccurate opinions are unlikely to deliver the desired outcomes. Attitudinal surveys associated with engagement campaigns are essential to improve stakeholder knowledge, advancing the development of fit-for-purpose forest management that provides the required ecosystem services. PMID:24488084</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.B53K..02D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.B53K..02D"><span id="translatedtitle">Within-stand variability of leaf phenology in deciduous <span class="hlt">tree</span> <span class="hlt">species</span>: characterization and ecological implications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Delpierre, N.; Cecchini, S.; Dufrêne, E.; Guillemot, J.; Nicolas, M.</p> <p>2014-12-01</p> <p>The vast majority of phenological studies address questions relative to the spatial or temporal variability of phenological timings integrated at the forest stand (i.e. <span class="hlt">tree</span> population) scale. Within a forest stand, the inter-individual variability of phenological timings is expected to affect a range of <span class="hlt">tree</span> functions among which the access to light, the use of carbon and nitrogen reserves, the absorption of minerals and the sensitivity to pathogens. Hence the individual's phenological traits are likely to be strongly selected, resulting in an adaptation of the population to local conditions, as evidenced by latitudinal and altitudinal clines observed in common garden experiments. Studies dedicated to the within-stand variability of the timing of phenophases have to date been mostly designed for contrasting the behaviours of understory versus overstory <span class="hlt">species</span> or seedlings compared to their adult conspecifics. The few published papers studying the phenological timings among adult conspecifics revealed unclear patterns. We aimed at clarifying the understanding of the within-stand variability of <span class="hlt">tree</span> phenology of three of the main European deciduous <span class="hlt">species</span> (Quercus petraea, Quercus robur and Fagus sylvatica) through the analysis of a unique phenological database collected over 44 (28 Oak sites, 16 Beech stands) forest stands at the <span class="hlt">tree</span> level for 4 years over France. We show that within a forest stand, individual <span class="hlt">trees</span> have a distinct "phenological identity" resulting in a year to year conservation of (a) the individuals' spring and autumn phenological rankings and (b) the individuals' critical temperature sums required for budburst and senescence. The individual's spring "phenological identity" affects its functioning and, ultimately, its competitive ability: big <span class="hlt">trees</span> burst earlier. Acknowledging that Angiosperms show low genetic diversity between populations, we show that the between-site variability of critical temperature sums needed for budburst or senescence</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16132448','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16132448"><span id="translatedtitle">Potential <span class="hlt">tree</span> <span class="hlt">species</span> for use in the restoration of unsanitary landfills.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kim, Kee Dae; Lee, Eun Ju</p> <p>2005-07-01</p> <p>Given that they represent the most economical option for disposing of refuse, waste landfills are widespread in urban areas. However, landfills generate air and water pollution and require restoration for landscape development. A number of unsanitary waste landfills have caused severe environmental problems in developing countries. This study aimed to investigate the colonization status of different <span class="hlt">tree</span> <span class="hlt">species</span> on waste landfills to assess their potential for restoring unsanitary landfills in South Korea. Plot surveys were conducted using 10 x 10-m quadrats at seven waste landfill sites: Bunsuri, Dugiri, Hasanundong, Gomaeri, Kyongseodong, Mojeonri, and Shindaedong. We determined the height, diameter at breast height (DBH), and number of <span class="hlt">tree</span> <span class="hlt">species</span> in the plots, and enumerated all saplings < or =1 m high. Because black locust, Robinia pseudoacacia, was the dominant <span class="hlt">tree</span> <span class="hlt">species</span> in the waste landfills, we measured the distance from the presumed mother plant (i.e., the tallest black locust in a patch), height, and DBH of all individuals in black locust patches to determine patch structure. Robinia pseudoacacia, Salix koreensis, and Populus sieboldii formed canopy layers in the waste landfills. The basal area of black locust was 1.51 m(2)/ha, and this <span class="hlt">species</span> had the highest number of saplings among all <span class="hlt">tree</span> <span class="hlt">species</span>. The diameter of the black locust patches ranged from 3.71 to 11.29 m. As the patch diameter increased, the number of regenerated saplings also tended to increase, albeit not significantly. Black locust invaded via bud banks and spread clonally in a concentric pattern across the landfills. This <span class="hlt">species</span> grew well in the dry habitat of the landfills, and its growth rate was very high. Furthermore, black locust has the ability to fix nitrogen symbiotically; it is therefore considered a well-adapted <span class="hlt">species</span> for waste landfills. Eleven woody <span class="hlt">species</span> were selected for screening: Acer palmatum, Albizzia julibrissin, Buxus microphylla var. koreana, Ginkgo</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26853539','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26853539"><span id="translatedtitle">Development of oligonucleotide microarrays for simultaneous multi-<span class="hlt">species</span> identification of Phellinus <span class="hlt">tree</span>-pathogenic fungi.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tzean, Yuh; Shu, Po-Yao; Liou, Ruey-Fen; Tzean, Shean-Shong</p> <p>2016-03-01</p> <p>Polyporoid Phellinus fungi are ubiquitously present in the environment and play an important role in shaping forest ecology. Several <span class="hlt">species</span> of Phellinus are notorious pathogens that can affect a broad variety of <span class="hlt">tree</span> <span class="hlt">species</span> in forest, plantation, orchard and urban habitats; however, current detection methods are overly complex and lack the sensitivity required to identify these pathogens at the <span class="hlt">species</span> level in a timely fashion for effective infestation control. Here, we describe eight oligonucleotide microarray platforms for the simultaneous and specific detection of 17 important Phellinus <span class="hlt">species</span>, using probes generated from the internal transcribed spacer regions unique to each <span class="hlt">species</span>. The sensitivity, robustness and efficiency of this Phellinus microarray system was subsequently confirmed against template DNA from two key Phellinus <span class="hlt">species</span>, as well as field samples collected from <span class="hlt">tree</span> roots, trunks and surrounding soil. This system can provide early, specific and convenient detection of Phellinus <span class="hlt">species</span> for forestry, arboriculture and quarantine inspection, and could potentially help to mitigate the environmental and economic impact of Phellinus-related diseases. PMID:26853539</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4961160','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4961160"><span id="translatedtitle">The probability of monophyly of a sample of gene lineages on a <span class="hlt">species</span> <span class="hlt">tree</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Mehta, Rohan S.; Bryant, David; Rosenberg, Noah A.</p> <p>2016-01-01</p> <p>Monophyletic groups—groups that consist of all of the descendants of a most recent common ancestor—arise naturally as a consequence of descent processes that result in meaningful distinctions between organisms. Aspects of monophyly are therefore central to fields that examine and use genealogical descent. In particular, studies in conservation genetics, phylogeography, population genetics, <span class="hlt">species</span> delimitation, and systematics can all make use of mathematical predictions under evolutionary models about features of monophyly. One important calculation, the probability that a set of gene lineages is monophyletic under a two-<span class="hlt">species</span> neutral coalescent model, has been used in many studies. Here, we extend this calculation for a <span class="hlt">species</span> <span class="hlt">tree</span> model that contains arbitrarily many <span class="hlt">species</span>. We study the effects of <span class="hlt">species</span> <span class="hlt">tree</span> topology and branch lengths on the monophyly probability. These analyses reveal new behavior, including the maintenance of nontrivial monophyly probabilities for gene lineage samples that span multiple <span class="hlt">species</span> and even for lineages that do not derive from a monophyletic <span class="hlt">species</span> group. We illustrate the mathematical results using an example application to data from maize and teosinte. PMID:27432988</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2677233','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2677233"><span id="translatedtitle">The demography of range boundaries versus range cores in eastern US <span class="hlt">tree</span> <span class="hlt">species</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Purves, Drew W.</p> <p>2009-01-01</p> <p>Regional species–climate correlations are well documented, but little is known about the ecological processes responsible for generating these patterns. Using the data from over 690 000 individual <span class="hlt">trees</span> I estimated five demographic rates—canopy growth, understorey growth, canopy lifespan, understorey lifespan and per capita reproduction—for 19 common eastern US <span class="hlt">tree</span> <span class="hlt">species</span>, within the core and the northern and southern boundaries, of the <span class="hlt">species</span> range. Most <span class="hlt">species</span> showed statistically significant boundary versus core differences in most rates at both boundary types. Differences in canopy and understorey growth were relatively small in magnitude but consistent among <span class="hlt">species</span>, being lower at the northern (average −17%) and higher at the southern (average +12%) boundaries. Differences in lifespan were larger in magnitude but highly variable among <span class="hlt">species</span>, except for a marked trend for reduced canopy lifespan at the northern boundary (average −49%). Differences in per capita reproduction were large and statistically significant for some <span class="hlt">species</span>, but highly variable among <span class="hlt">species</span>. The rate estimates were combined to calculate two performance indices: R0 (a measure of lifetime fitness in the absence of competition) was consistently lower at the northern boundary (average −86%) whereas Z* (a measure of competitive ability in closed forest) showed no sign of a consistent boundary–core difference at either boundary. PMID:19324819</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27432988','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27432988"><span id="translatedtitle">The probability of monophyly of a sample of gene lineages on a <span class="hlt">species</span> <span class="hlt">tree</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mehta, Rohan S; Bryant, David; Rosenberg, Noah A</p> <p>2016-07-19</p> <p>Monophyletic groups-groups that consist of all of the descendants of a most recent common ancestor-arise naturally as a consequence of descent processes that result in meaningful distinctions between organisms. Aspects of monophyly are therefore central to fields that examine and use genealogical descent. In particular, studies in conservation genetics, phylogeography, population genetics, <span class="hlt">species</span> delimitation, and systematics can all make use of mathematical predictions under evolutionary models about features of monophyly. One important calculation, the probability that a set of gene lineages is monophyletic under a two-<span class="hlt">species</span> neutral coalescent model, has been used in many studies. Here, we extend this calculation for a <span class="hlt">species</span> <span class="hlt">tree</span> model that contains arbitrarily many <span class="hlt">species</span>. We study the effects of <span class="hlt">species</span> <span class="hlt">tree</span> topology and branch lengths on the monophyly probability. These analyses reveal new behavior, including the maintenance of nontrivial monophyly probabilities for gene lineage samples that span multiple <span class="hlt">species</span> and even for lineages that do not derive from a monophyletic <span class="hlt">species</span> group. We illustrate the mathematical results using an example application to data from maize and teosinte. PMID:27432988</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.9950I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.9950I"><span id="translatedtitle">Leaf and whole-<span class="hlt">tree</span> water use relations of Australian rainforest <span class="hlt">species</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ishida, Yoko; Laurance, Susan; Liddell, Michael; Lloyd, Jonathan</p> <p>2015-04-01</p> <p>Climate change induces drought events and may therefore cause significant impact on tropical rainforests, where most plants are reliant on high water availability - potentially affecting the distribution, composition and abundance of plant <span class="hlt">species</span>. Using an experimental approach, we are studying the effects of a simulated drought on lowland rainforest plants at the Daintree Rainforest Observatory (DRO), in tropical northern Australia. Before to build up the rainout infrastructure, we installed sap flow meters (HRM) on 62 rainforest <span class="hlt">trees</span>. Eight <span class="hlt">tree</span> <span class="hlt">species</span> were selected with diverse ecological strategies including wood density values ranging from 0.34 to 0.88 g/cm3 and could be replicated within a 1ha plot: Alstonia scholaris (Apocynaceae), Argyrondendron peralatum (Malvaceae), Elaeocarpus angustifolius (Elaeocarpaceae), Endiandra microneura (Lauraceae), Myristica globosa (Myristicaceae), Syzygium graveolens (Myrtaceae), Normanbya normanbyi (Arecaceae), and Castanospermum australe (Fabaceae). Our preliminary results from sap flow data obtained from October 2013 to December of 2014 showed differences in the amount of water used by our <span class="hlt">trees</span> varied in response to <span class="hlt">species</span>, size and climate. For example Syzygium graveolens has used a maximum of 60 litres/day while Argyrondendrum peralatum used 13 litres/day. Other potential causes for differential water-use between <span class="hlt">species</span> and the implications of our research will be discussed. We will continue to monitor sap flow during the rainfall exclusion (2014 to 2016) to determine the effects of plant physiological traits on water use strategies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://dx.doi.org/10.1139/X10-199','USGSPUBS'); return false;" href="http://dx.doi.org/10.1139/X10-199"><span id="translatedtitle"><span class="hlt">Tree</span> <span class="hlt">species</span> and soil nutrient profiles in old-growth forests of the Oregon Coast Range</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Cross, Alison; Perakis, Steven S.</p> <p>2011-01-01</p> <p>Old-growth forests of the Pacific Northwest provide a unique opportunity to examine <span class="hlt">tree</span> <span class="hlt">species</span> – soil relationships in ecosystems that have developed without significant human disturbance. We characterized foliage, forest floor, and mineral soil nutrients associated with four canopy <span class="hlt">tree</span> <span class="hlt">species</span> (Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco), western hemlock (Tsuga heterophylla (Raf.) Sarg.), western redcedar (Thuja plicata Donn ex D. Don), and bigleaf maple (Acer macrophyllum Pursh)) in eight old-growth forests of the Oregon Coast Range. The greatest forest floor accumulations of C, N, P, Ca, Mg, and K occurred under Douglas-fir, primarily due to greater forest floor mass. In mineral soil, western hemlock exhibited significantly lower Ca concentration and sum of cations (Ca + Mg + K) than bigleaf maple, with intermediate values for Douglas-fir and western redcedar. Bigleaf maple explained most <span class="hlt">species</span>-based differences in foliar nutrients, displaying high concentrations of N, P, Ca, Mg, and K. Foliar P and N:P variations largely reflected soil P variation across sites. The four <span class="hlt">tree</span> <span class="hlt">species</span> that we examined exhibited a number of individualistic effects on soil nutrient levels that contribute to biogeochemical heterogeneity in these ecosystems. Where fire suppression and long-term succession favor dominance by highly shade-tolerant western hemlock, our results suggest a potential for declines in both soil Ca availability and soil biogeochemical heterogeneity in old-growth forests.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/318771','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/318771"><span id="translatedtitle">How environmental conditions affect canopy leaf-level photosynthesis in four deciduous <span class="hlt">tree</span> <span class="hlt">species</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bassow, S.L.; Bazzaz, F.A.</p> <p>1998-12-01</p> <p><span class="hlt">Species</span> composition of temperate forests vary with successional age and seems likely to change in response to significant global climate change. Because photosynthesis rates in co-occurring <span class="hlt">tree</span> <span class="hlt">species</span> can differ in their sensitivity to environmental conditions, these changes in <span class="hlt">species</span> composition are likely to alter the carbon dynamics of temperate forests. To help improve their understanding of such atmosphere-biosphere interactions, the authors explored changes in leaf-level photosynthesis in a 60--70 yr old temperate mixed-deciduous forest in Petersham, Massachusetts (USA). Diurnally and seasonally varying environmental conditions differentially influenced in situ leaf-level photosynthesis rates in the canopies of four mature temperate deciduous <span class="hlt">tree</span> <span class="hlt">species</span>: red oak (Quercus rubra), red maple (Acer rubrum), white birch (Betula papyrifera), and yellow birch (Betula alleghaniensis). The authors measured in situ photosynthesis at two heights within the canopies through a diurnal time course on 7 d over two growing seasons. They simultaneously measured a suite of environmental conditions surrounding the leaf at the time of each measurement. The authors used path analysis to examine the influence of environmental factors on in situ photosynthesis in the <span class="hlt">tree</span> canopies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015NatGe...8..228R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015NatGe...8..228R"><span id="translatedtitle">Influence of <span class="hlt">tree</span> <span class="hlt">species</span> on continental differences in boreal fires and climate feedbacks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rogers, Brendan M.; Soja, Amber J.; Goulden, Michael L.; Randerson, James T.</p> <p>2015-03-01</p> <p>Wildfires are common in boreal forests around the globe and strongly influence ecosystem processes. However, North American forests support more high-intensity crown fires than Eurasia, where lower-intensity surface fires are common. These two types of fire can result in different net effects on climate as a consequence of their contrasting impacts on terrestrial albedo and carbon stocks. Here we use remote-sensing imagery, climate reanalysis data and forest inventories to evaluate differences in boreal fire dynamics between North America and Eurasia and their key drivers. Eurasian fires were less intense, destroyed less live vegetation, killed fewer <span class="hlt">trees</span> and generated a smaller negative shortwave forcing. As fire weather conditions were similar across continents, we suggest that different fire dynamics between the two continents resulted from their dominant <span class="hlt">tree</span> <span class="hlt">species</span>. In particular, <span class="hlt">species</span> that have evolved to spread and be consumed by crown fires as part of their life cycle dominate North American boreal forests. In contrast, <span class="hlt">tree</span> <span class="hlt">species</span> that have evolved to resist and suppress crown fires dominate Eurasian boreal forests. We conclude that <span class="hlt">species</span>-level traits must be considered in global evaluations of the effects of fire on emissions and climate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=244048','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=244048"><span id="translatedtitle">Microbiology of Wetwood: Importance of Pectin Degradation and Clostridium <span class="hlt">Species</span> in Living <span class="hlt">Trees</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Schink, Bernhard; Ward, James C.; Zeikus, J. Gregory</p> <p>1981-01-01</p> <p>Wetwood samples from standing <span class="hlt">trees</span> of eastern cottonwood (Populus deltoides), black poplar (Populus nigra), and American elm (Ulmus americana) contained high numbers of aerobic and anaerobic pectin-degrading bacteria (104 to 106 cells per g of wood). High activity of polygalacturonate lyase (≤0.5 U/ml) was also detected in the fetid liquid that spurted from wetwood zones in the lower trunk when the <span class="hlt">trees</span> were bored. A prevalent pectin-degrading obligately anaerobic bacterium isolated from these wetwoods was identified as Clostridium butyricum. Pectin decomposition by C. butyricum strain 4P1 was associated with an inducible polygalacturonate lyase and pectin methylesterase, the same types of pectinolytic activity expressed in the wetwood of these <span class="hlt">trees</span>. The pH optimum of the extracellular polygalacturonate lyase was alkaline (near pH 8.5). In vitro tests with sapwood samples from a conifer (Douglas fir, Pseudotsuga menziesii) showed that tori in membranes of bordered pits are degraded by pure cultures of strain 4P1, polygalacturonate lyase enzyme preparations of strain 4P1, and mixed methanogenic cultures from the <span class="hlt">tree</span> samples of wetwood. These results provide evidence that pectin in xylem tissue is actively degraded by C. butyricum strain 4P1 via polygalacturonate lyase activity. The importance of pectin degradation by bacteria, including Clostridium <span class="hlt">species</span>, appears paramount in the formation and maintenance of the wetwood syndrome in certain living <span class="hlt">trees</span>. Images PMID:16345848</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18459337','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18459337"><span id="translatedtitle">Large ontogenetic declines in intra-crown leaf area index in two temperate deciduous <span class="hlt">tree</span> <span class="hlt">species</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nock, C A; Caspersen, J P; Thomas, S C</p> <p>2008-03-01</p> <p>The widespread occurrence of age-related changes in leaf morphology and allocation suggests that the leaf area index of individual <span class="hlt">trees</span> (intra-crown LAI) may decline late in ontogeny. We used direct, within-canopy measurements to quantify the LAI of canopy <span class="hlt">trees</span> with exposed crowns of two temperate deciduous <span class="hlt">species</span>. Intra-crown LAI declined from approximately 7 to 4 in Acer saccharum, and from approximately 9.5 to 6.5 in Betula alleghaniensis, as <span class="hlt">tree</span> size increased (from 15 to 72 cm diameter at breast height [dbh]). For A. saccharum, age (which varied from 30 to 160 years) was a significantly better predictor of LAI decline than dbh. We also modeled the effect of ontogenetic declines in LAI on understory light availability and found that light transmission increases significantly as canopy <span class="hlt">trees</span> grow and mature. Our results thus suggest that gradual declines in LAI with <span class="hlt">tree</span> age may play an important and overlooked role in contributing to the heterogeneity of sub-canopy light regimes in mature forests. PMID:18459337</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25168006','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25168006"><span id="translatedtitle">Influence of shade tolerance and development stage on the allometry of ten temperate <span class="hlt">tree</span> <span class="hlt">species</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Franceschini, Tony; Schneider, Robert</p> <p>2014-11-01</p> <p>Allometry studies the change in scale between two dimensions of an organism. The metabolic theory of ecology predicts invariant allometric scaling exponents, while empirical studies evidenced inter- and intra-specific variations. This work aimed at identifying the sources of variations of the allometric exponents at both inter- and intra-specific levels using stem analysis from 9,363 <span class="hlt">trees</span> for ten Eastern Canada <span class="hlt">species</span> with a large shade-tolerance gradient. Specifically, the yearly allometric exponents, α(v,DBH) [volume (v) and diameter at breast height (DBH)], β(v,h) [v and height (h)], and γ(h,DBH) (h and DBH) were modelled as a function of <span class="hlt">tree</span> age for each <span class="hlt">species</span>. α(v,DBH), and γ(h,DBH) increased with <span class="hlt">tree</span> age and then reached a plateau ranging from 2.45 to 3.12 for α(v,DBH), and 0.874-1.48 for γ(h,DBH). Pine <span class="hlt">species</span> presented a local maximum. No effect of <span class="hlt">tree</span> age on β(v,h) was found for conifers, while it increased until a plateau ranging from 3.71 to 5.16 for broadleaves. The influence of shade tolerance on the growth trajectories was then explored. In the juvenile stage, α(v,DBH), and γ(h,DBH) increased with shade tolerance while β(v,h) was shade-tolerance independent. In the mature stage, β(v,h) increased with shade tolerance, whereas γ(h,DBH) decreased and α(v,DBH) was shade-tolerance independent. The interaction between development stage and shade tolerance for allometric exponents demonstrates the importance of the changing functional requirements of <span class="hlt">trees</span> for resource allocation at both the inter- and intra-specific level. These results indicate the need to also integrate specific functional traits, growth strategies and allocation, in allometric theoretical frameworks. PMID:25168006</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/19197495','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/19197495"><span id="translatedtitle">Diurnal and seasonal carbon balance of four tropical <span class="hlt">tree</span> <span class="hlt">species</span> differing in successional status.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Souza, G M; Ribeiro, R V; Sato, A M; Oliveira, M S</p> <p>2008-11-01</p> <p>This study addressed some questions about how a suitable leaf carbon balance can be attained for different functional groups of tropical <span class="hlt">tree</span> <span class="hlt">species</span> under contrasting forest light environments. The study was carried out in a fragment of semi-deciduous seasonal forest in Narandiba county, São Paulo Estate, Brazil. 10-month-old seedlings of four tropical <span class="hlt">tree</span> <span class="hlt">species</span>, Bauhinia forficata Link (Caesalpinioideae) and Guazuma ulmifolia Lam. (Sterculiaceae) as light-demanding pioneer <span class="hlt">species</span>, and Hymenaea courbaril L. (Caesalpinioideae) and Esenbeckia leiocarpa Engl. (Rutaceae) as late successional <span class="hlt">species</span>, were grown under gap and understorey conditions. Diurnal courses of net photosynthesis (Pn) and transpiration were recorded with an open system portable infrared gas analyzer in two different seasons. Dark respiration and photorespiration were also evaluated in the same leaves used for Pn measurements after dark adaptation. Our results showed that diurnal-integrated dark respiration (Rdi) of late successional <span class="hlt">species</span> were similar to pioneer <span class="hlt">species</span>. On the other hand, photorespiration rates were often higher in pioneer than in late successional <span class="hlt">species</span> in the gap. However, the relative contribution of these parameters to leaf carbon balance was similar in all <span class="hlt">species</span> in both environmental conditions. Considering diurnal-integrated values, gross photosynthesis (Pgi) was dramatically higher in gap than in understorey, regardless of <span class="hlt">species</span>. In both evaluated months, there were no differences among <span class="hlt">species</span> of different functional groups under shade conditions. The same was observed in May (dry season) under gap conditions. In such light environment, pioneers were distinguished from late successional <span class="hlt">species</span> in November (wet season), showing that ecophysiological performance can have a straightforward relation to seasonality. PMID:19197495</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70174016','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70174016"><span id="translatedtitle">Do the rich get richer? Varying effects of <span class="hlt">tree</span> <span class="hlt">species</span> identity and diversity on the richness of understory taxa</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Champagne, Juilette; Paine, C. E. Timothy; Schoolmaster, Donald; Stejskal, Robert; Volařík, Daniel; Šebesta, Jan; Trnka, Filip; Koutecký, Tomáš; Švarc, Petr; Svátek, Martin; Hector, Andy; Matula, Radim</p> <p>2016-01-01</p> <p>Understory herbs and soil invertebrates play key roles in soil formation and nutrient cycling in forests. Studies suggest that diversity in the canopy and in the understory are positively associated, but these studies often confound the effects of <span class="hlt">tree</span> <span class="hlt">species</span> diversity with those of <span class="hlt">tree</span> <span class="hlt">species</span> identity and abiotic conditions. We combined extensive field sampling with structural equation modeling to evaluate the simultaneous effects of <span class="hlt">tree</span> diversity on the <span class="hlt">species</span> diversity of understory herbs, beetles, and earthworms. The diversity of earthworms and saproxylic beetles was directly and positively associated with <span class="hlt">tree</span> diversity, presumably because <span class="hlt">species</span> of both these taxa specialize on certain <span class="hlt">species</span> of <span class="hlt">trees</span>. <span class="hlt">Tree</span> identity also strongly affected diversity in the understory, especially for herbs, likely as a result of interspecific differences in canopy light transmittance or litter decomposition rates. Our results suggest that changes in forest management will disproportionately affect certain understory taxa. For instance, changes in canopy diversity will affect the diversity of earthworms and saproxylic beetles more than changes in <span class="hlt">tree</span> <span class="hlt">species</span> composition, whereas the converse would be expected for understory herbs and detritivorous beetles. We conclude that the effects of <span class="hlt">tree</span> diversity on understory taxa can vary from positive to negative and may affect biogeochemical cycling in temperate forests. Thus, maintaining high diversity in temperate forests can promote the diversity of multiple taxa in the understory.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25811074','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25811074"><span id="translatedtitle">Experimental evidence of large changes in terrestrial chlorine cycling following altered <span class="hlt">tree</span> <span class="hlt">species</span> composition.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Montelius, Malin; Thiry, Yves; Marang, Laura; Ranger, Jacques; Cornelis, Jean-Thomas; Svensson, Teresia; Bastviken, David</p> <p>2015-04-21</p> <p>Organochlorine molecules (Clorg) are surprisingly abundant in soils and frequently exceed chloride (Cl(-)) levels. Despite the widespread abundance of Clorg and the common ability of microorganisms to produce Clorg, we lack fundamental knowledge about how overall chlorine cycling is regulated in forested ecosystems. Here we present data from a long-term reforestation experiment where native forest was cleared and replaced with five different <span class="hlt">tree</span> <span class="hlt">species</span>. Our results show that the abundance and residence times of Cl(-) and Clorg after 30 years were highly dependent on which <span class="hlt">tree</span> <span class="hlt">species</span> were planted on the nearby plots. Average Cl(-) and Clorg content in soil humus were higher, at experimental plots with coniferous <span class="hlt">trees</span> than in those with deciduous <span class="hlt">trees</span>. Plots with Norway spruce had the highest net accumulation of Cl(-) and Clorg over the experiment period, and showed a 10 and 4 times higher Cl(-) and Clorg storage (kg ha(-1)) in the biomass, respectively, and 7 and 9 times higher storage of Cl(-) and Clorg in the soil humus layer, compared to plots with oak. The results can explain why local soil chlorine levels are frequently independent of atmospheric deposition, and provide opportunities for improved modeling of chlorine distribution and cycling in terrestrial ecosystems. PMID:25811074</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25084460','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25084460"><span id="translatedtitle">Epigenetic variability in the genetically uniform forest <span class="hlt">tree</span> <span class="hlt">species</span> Pinus pinea L.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sáez-Laguna, Enrique; Guevara, María-Ángeles; Díaz, Luis-Manuel; Sánchez-Gómez, David; Collada, Carmen; Aranda, Ismael; Cervera, María-Teresa</p> <p>2014-01-01</p> <p>There is an increasing interest in understanding the role of epigenetic variability in forest <span class="hlt">species</span> and how it may contribute to their rapid adaptation to changing environments. In this study we have conducted a genome-wide analysis of cytosine methylation pattern in Pinus pinea, a <span class="hlt">species</span> characterized by very low levels of genetic variation and a remarkable degree of phenotypic plasticity. DNA methylation profiles of different vegetatively propagated <span class="hlt">trees</span> from representative natural Spanish populations of P. pinea were analyzed with the Methylation Sensitive Amplified Polymorphism (MSAP) technique. A high degree of cytosine methylation was detected (64.36% of all scored DNA fragments). Furthermore, high levels of epigenetic variation were observed among the studied individuals. This high epigenetic variation found in P. pinea contrasted with the lack of genetic variation based on Amplified Fragment Length Polymorphism (AFLP) data. In this manner, variable epigenetic markers clearly discriminate individuals and differentiates two well represented populations while the lack of genetic variation revealed with the AFLP markers fail to differentiate at both, individual or population levels. In addition, the use of different replicated <span class="hlt">trees</span> allowed identifying common polymorphic methylation sensitive MSAP markers among replicates of a given propagated <span class="hlt">tree</span>. This set of MSAPs allowed discrimination of the 70% of the analyzed <span class="hlt">trees</span>. PMID:25084460</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4118849','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4118849"><span id="translatedtitle">Epigenetic Variability in the Genetically Uniform Forest <span class="hlt">Tree</span> <span class="hlt">Species</span> Pinus pinea L</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Sáez-Laguna, Enrique; Guevara, María-Ángeles; Díaz, Luis-Manuel; Sánchez-Gómez, David; Collada, Carmen; Aranda, Ismael; Cervera, María-Teresa</p> <p>2014-01-01</p> <p>There is an increasing interest in understanding the role of epigenetic variability in forest <span class="hlt">species</span> and how it may contribute to their rapid adaptation to changing environments. In this study we have conducted a genome-wide analysis of cytosine methylation pattern in Pinus pinea, a <span class="hlt">species</span> characterized by very low levels of genetic variation and a remarkable degree of phenotypic plasticity. DNA methylation profiles of different vegetatively propagated <span class="hlt">trees</span> from representative natural Spanish populations of P. pinea were analyzed with the Methylation Sensitive Amplified Polymorphism (MSAP) technique. A high degree of cytosine methylation was detected (64.36% of all scored DNA fragments). Furthermore, high levels of epigenetic variation were observed among the studied individuals. This high epigenetic variation found in P. pinea contrasted with the lack of genetic variation based on Amplified Fragment Length Polymorphism (AFLP) data. In this manner, variable epigenetic markers clearly discriminate individuals and differentiates two well represented populations while the lack of genetic variation revealed with the AFLP markers fail to differentiate at both, individual or population levels. In addition, the use of different replicated <span class="hlt">trees</span> allowed identifying common polymorphic methylation sensitive MSAP markers among replicates of a given propagated <span class="hlt">tree</span>. This set of MSAPs allowed discrimination of the 70% of the analyzed <span class="hlt">trees</span>. PMID:25084460</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015ISPAr.XL3..473F&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015ISPAr.XL3..473F&link_type=ABSTRACT"><span id="translatedtitle">On the Use of Shortwave Infrared for <span class="hlt">Tree</span> <span class="hlt">Species</span> Discrimination in Tropical Semideciduous Forest</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ferreira, M. P.; Zortea, M.; Zanotta, D. C.; Féret, J. B.; Shimabukuro, Y. E.; Souza Filho, C. R.</p> <p>2015-08-01</p> <p><span class="hlt">Tree</span> <span class="hlt">species</span> mapping in tropical forests provides valuable insights for forest managers. Keystone <span class="hlt">species</span> can be located for collection of seeds for forest restoration, reducing fieldwork costs. However, mapping of <span class="hlt">tree</span> <span class="hlt">species</span> in tropical forests using remote sensing data is a challenge due to high floristic and spectral diversity. Little is known about the use of different spectral regions as most of studies performed so far used visible/near-infrared (390-1000 nm) features. In this paper we show the contribution of shortwave infrared (SWIR, 1045-2395 nm) for <span class="hlt">tree</span> <span class="hlt">species</span> discrimination in a tropical semideciduous forest. Using high-resolution hyperspectral data we also simulated WorldView-3 (WV-3) multispectral bands for classification purposes. Three machine learning methods were tested to discriminate <span class="hlt">species</span> at the pixel-level: Linear Discriminant Analysis (LDA), Support Vector Machines with Linear (L-SVM) and Radial Basis Function (RBF-SVM) kernels, and Random Forest (RF). Experiments were performed using all and selected features from the VNIR individually and combined with SWIR. Feature selection was applied to evaluate the effects of dimensionality reduction and identify potential wavelengths that may optimize <span class="hlt">species</span> discrimination. Using VNIR hyperspectral bands, RBF-SVM achieved the highest average accuracy (77.4%). Inclusion of the SWIR increased accuracy to 85% with LDA. The same pattern was also observed when WV-3 simulated channels were used to classify the <span class="hlt">species</span>. The VNIR bands provided and accuracy of 64.2% for LDA, which was increased to 79.8 % using the new SWIR bands that are operationally available in this platform. Results show that incorporating SWIR bands increased significantly average accuracy for both the hyperspectral data and WorldView-3 simulated bands.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23504733','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23504733"><span id="translatedtitle"><span class="hlt">Tree</span> <span class="hlt">species</span> diversity interacts with elevated CO2 to induce a greater root system response.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Smith, Andrew R; Lukac, Martin; Bambrick, Michael; Miglietta, Franco; Godbold, Douglas L</p> <p>2013-01-01</p> <p>As a consequence of land-use change and the burning of fossil fuels, atmospheric concentrations of CO2 are increasing and altering the dynamics of the carbon cycle in forest ecosystems. In a number of studies using single <span class="hlt">tree</span> <span class="hlt">species</span>, fine root biomass has been shown to be strongly increased by elevated CO2 . However, natural forests are often intimate mixtures of a number of co-occurring <span class="hlt">species</span>. To investigate the interaction between <span class="hlt">tree</span> mixture and elevated CO2 , Alnus glutinosa, Betula pendula and Fagus sylvatica were planted in areas of single <span class="hlt">species</span> and a three <span class="hlt">species</span> polyculture in a free-air CO2 enrichment study (BangorFACE). The <span class="hlt">trees</span> were exposed to ambient or elevated CO2 (580 μmol mol(-1) ) for 4 years. Fine and coarse root biomass, together with fine root turnover and fine root morphological characteristics were measured. Fine root biomass and morphology responded differentially to the elevated CO2 at different soil depths in the three <span class="hlt">species</span> when grown in monocultures. In polyculture, a greater response to elevated CO2 was observed in coarse roots to a depth of 20 cm, and fine root area index to a depth of 30 cm. Total fine root biomass was positively affected by elevated CO2 at the end of the experiment, but not by <span class="hlt">species</span> diversity. Our data suggest that existing biogeochemical cycling models parameterized with data from <span class="hlt">species</span> grown in monoculture may be underestimating the belowground response to global change. PMID:23504733</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25225398','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25225398"><span id="translatedtitle">Predicting <span class="hlt">species</span>' range limits from functional traits for the <span class="hlt">tree</span> flora of North America.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Stahl, Ulrike; Reu, Björn; Wirth, Christian</p> <p>2014-09-23</p> <p>Using functional traits to explain <span class="hlt">species</span>' range limits is a promising approach in functional biogeography. It replaces the idiosyncrasy of <span class="hlt">species</span>-specific climate ranges with a generic trait-based predictive framework. In addition, it has the potential to shed light on specific filter mechanisms creating large-scale vegetation patterns. However, its application to a continental flora, spanning large climate gradients, has been hampered by a lack of trait data. Here, we explore whether five key plant functional traits (seed mass, wood density, specific leaf area (SLA), maximum height, and longevity of a <span class="hlt">tree</span>)--indicative of life history, mechanical, and physiological adaptations--explain the climate ranges of 250 North American <span class="hlt">tree</span> <span class="hlt">species</span> distributed from the boreal to the subtropics. Although the relationship between traits and the median climate across a <span class="hlt">species</span> range is weak, quantile regressions revealed strong effects on range limits. Wood density and seed mass were strongly related to the lower but not upper temperature range limits of <span class="hlt">species</span>. Maximum height affects the <span class="hlt">species</span> range limits in both dry and humid climates, whereas SLA and longevity do not show clear relationships. These results allow the definition and delineation of climatic "no-go areas" for North American <span class="hlt">tree</span> <span class="hlt">species</span> based on key traits. As some of these key traits serve as important parameters in recent vegetation models, the implementation of trait-based climatic constraints has the potential to predict both range shifts and ecosystem consequences on a more functional basis. Moreover, for future trait-based vegetation models our results provide a benchmark for model evaluation. PMID:25225398</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22666497','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22666497"><span id="translatedtitle">Strong neutral spatial effects shape <span class="hlt">tree</span> <span class="hlt">species</span> distributions across life stages at multiple scales.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hu, Yue-Hua; Lan, Guo-Yu; Sha, Li-Qing; Cao, Min; Tang, Yong; Li, Yi-De; Xu, Da-Ping</p> <p>2012-01-01</p> <p>Traditionally, ecologists use lattice (regional summary) count data to simulate <span class="hlt">tree</span> <span class="hlt">species</span> distributions to explore <span class="hlt">species</span> coexistence. However, no previous study has explicitly compared the difference between using lattice count and basal area data and analyzed <span class="hlt">species</span> distributions at both individual <span class="hlt">species</span> and community levels while simultaneously considering the combined scenarios of life stage and scale. In this study, we hypothesized that basal area data are more closely related to environmental variables than are count data because of strong environmental filtering effects. We also address the contribution of niche and the neutral (i.e., solely dependent on distance) factors to <span class="hlt">species</span> distributions. Specifically, we separately modeled count data and basal area data while considering life stage and scale effects at the two levels with simultaneous autoregressive models and variation partitioning. A principal coordinates of neighbor matrix (PCNM) was used to model neutral spatial effects at the community level. The explained variations of <span class="hlt">species</span> distribution data did not differ significantly between the two types of data at either the individual <span class="hlt">species</span> level or the community level, indicating that the two types of data can be used nearly identically to model <span class="hlt">species</span> distributions. Neutral spatial effects represented by spatial autoregressive parameters and the PCNM eigenfunctions drove <span class="hlt">species</span> distributions on multiple scales, different life stages and individual <span class="hlt">species</span> and community levels in this plot. We concluded that strong neutral spatial effects are the principal mechanisms underlying the <span class="hlt">species</span> distributions and thus shape biodiversity spatial patterns. PMID:22666497</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3362550','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3362550"><span id="translatedtitle">Strong Neutral Spatial Effects Shape <span class="hlt">Tree</span> <span class="hlt">Species</span> Distributions across Life Stages at Multiple Scales</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hu, Yue-Hua; Lan, Guo-Yu; Sha, Li-Qing; Cao, Min; Tang, Yong; Li, Yi-De; Xu, Da-Ping</p> <p>2012-01-01</p> <p>Traditionally, ecologists use lattice (regional summary) count data to simulate <span class="hlt">tree</span> <span class="hlt">species</span> distributions to explore <span class="hlt">species</span> coexistence. However, no previous study has explicitly compared the difference between using lattice count and basal area data and analyzed <span class="hlt">species</span> distributions at both individual <span class="hlt">species</span> and community levels while simultaneously considering the combined scenarios of life stage and scale. In this study, we hypothesized that basal area data are more closely related to environmental variables than are count data because of strong environmental filtering effects. We also address the contribution of niche and the neutral (i.e., solely dependent on distance) factors to <span class="hlt">species</span> distributions. Specifically, we separately modeled count data and basal area data while considering life stage and scale effects at the two levels with simultaneous autoregressive models and variation partitioning. A principal coordinates of neighbor matrix (PCNM) was used to model neutral spatial effects at the community level. The explained variations of <span class="hlt">species</span> distribution data did not differ significantly between the two types of data at either the individual <span class="hlt">species</span> level or the community level, indicating that the two types of data can be used nearly identically to model <span class="hlt">species</span> distributions. Neutral spatial effects represented by spatial autoregressive parameters and the PCNM eigenfunctions drove <span class="hlt">species</span> distributions on multiple scales, different life stages and individual <span class="hlt">species</span> and community levels in this plot. We concluded that strong neutral spatial effects are the principal mechanisms underlying the <span class="hlt">species</span> distributions and thus shape biodiversity spatial patterns. PMID:22666497</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/15092455','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/15092455"><span id="translatedtitle">Effect of chlorine pollution on three fruit <span class="hlt">tree</span> <span class="hlt">species</span> at Ranoli near Baroda, India.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Vijayan, R; Bedi, S J</p> <p>1989-01-01</p> <p>This paper describes the effect of chlorine pollution from an alkalies and chemical plant at Ranoli, near Baroda, on three tropical fruit <span class="hlt">tree</span> <span class="hlt">species</span>-Mangifera indica L. (mango) Manilkara hexandra Dubard. (rayan) and Syzygium cumini Skeels (Jamun). As compared to controls growing in a less polluted area, <span class="hlt">trees</span> growing close to the plant showed reduced mean leaf area, a higher percentage of leaf area damaged, a reduction in fruit yield, chlorophyll pigments, protein and carbohydrate content, and higher accumulation of chloride in the foliar tissues. The accumulation of pollutaant, chloride, in the foliar tissues was very high in mango and jamun. Based on the degree of damage to the plants, the <span class="hlt">species</span> studied were arranged in decreasing order of their sensitivity to chlorine pollution-mango, jamun and rayan. PMID:15092455</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21971584','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21971584"><span id="translatedtitle">Atmospheric change alters foliar quality of host <span class="hlt">trees</span> and performance of two outbreak insect <span class="hlt">species</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Couture, John J; Meehan, Timothy D; Lindroth, Richard L</p> <p>2012-03-01</p> <p>This study examined the independent and interactive effects of elevated carbon dioxide (CO(2)) and ozone (O(3)) on the foliar quality of two deciduous <span class="hlt">trees</span> <span class="hlt">species</span> and the performance of two outbreak herbivore <span class="hlt">species</span>. Trembling aspen (Populus tremuloides) and paper birch (Betula papyrifera) were grown at the Aspen FACE research site in northern Wisconsin, USA, under four combinations of ambient and elevated CO(2) and O(3). We measured the effects of elevated CO(2) and O(3) on aspen and birch phytochemistry and on gypsy moth (Lymantria dispar) and forest tent caterpillar (Malacosoma disstria) performance. Elevated CO(2) nominally affected foliar quality for both <span class="hlt">tree</span> <span class="hlt">species</span>. Elevated O(3) negatively affected aspen foliar quality, but only marginally influenced birch foliar quality. Elevated CO(2) slightly improved herbivore performance, while elevated O(3) decreased herbivore performance, and both responses were stronger on aspen than birch. Interestingly, elevated CO(2) largely offset decreased herbivore performance under elevated O(3). Nitrogen, lignin, and C:N were identified as having strong influences on herbivore performance when larvae were fed aspen, but no significant relationships were observed for insects fed birch. Our results support the notion that herbivore performance can be affected by atmospheric change through altered foliar quality, but how herbivores will respond will depend on interactions among CO(2), O(3), and <span class="hlt">tree</span> <span class="hlt">species</span>. An emergent finding from this study is that <span class="hlt">tree</span> age and longevity of exposure to pollutants may influence the effects of elevated CO(2) and O(3) on plant-herbivore interactions, highlighting the need to continue long-term atmospheric change research. PMID:21971584</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4324066','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4324066"><span id="translatedtitle">Do ectomycorrhizal and arbuscular mycorrhizal temperate <span class="hlt">tree</span> <span class="hlt">species</span> systematically differ in root order-related fine root morphology and biomass?</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Kubisch, Petra; Hertel, Dietrich; Leuschner, Christoph</p> <p>2015-01-01</p> <p>While most temperate broad-leaved <span class="hlt">tree</span> <span class="hlt">species</span> form ectomycorrhizal (EM) symbioses, a few <span class="hlt">species</span> have arbuscular mycorrhizas (AM). It is not known whether EM and AM <span class="hlt">tree</span> <span class="hlt">species</span> differ systematically with respect to fine root morphology, fine root system size and root functioning. In a <span class="hlt">species</span>-rich temperate mixed forest, we studied the fine root morphology and biomass of three EM and three AM <span class="hlt">tree</span> <span class="hlt">species</span> from the genera Acer, Carpinus, Fagus, Fraxinus, and Tilia searching for principal differences between EM and AM <span class="hlt">trees</span>. We further assessed the evidence of convergence or divergence in root traits among the six co-occurring <span class="hlt">species</span>. Eight fine root morphological and chemical traits were investigated in root segments of the first to fourth root order in three different soil depths and the relative importance of the factors root order, <span class="hlt">tree</span> <span class="hlt">species</span> and soil depth for root morphology was determined. Root order was more influential than <span class="hlt">tree</span> <span class="hlt">species</span> while soil depth had only a small effect on root morphology All six <span class="hlt">species</span> showed similar decreases in specific root length and specific root area from the 1st to the 4th root order, while the <span class="hlt">species</span> patterns differed considerably in root tissue density, root N concentration, and particularly with respect to root tip abundance. Most root morphological traits were not significantly different between EM and AM <span class="hlt">species</span> (except for specific root area that was larger in AM <span class="hlt">species</span>), indicating that mycorrhiza type is not a key factor influencing fine root morphology in these <span class="hlt">species</span>. The order-based root analysis detected <span class="hlt">species</span> differences more clearly than the simple analysis of bulked fine root mass. Despite convergence in important root traits among AM and EM <span class="hlt">species</span>, even congeneric <span class="hlt">species</span> may differ in certain fine root morphological traits. This suggests that, in general, <span class="hlt">species</span> identity has a larger influence on fine root morphology than mycorrhiza type. PMID:25717334</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25204074','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25204074"><span id="translatedtitle">Effects of <span class="hlt">tree</span> <span class="hlt">species</span> and wood particle size on the properties of cement-bonded particleboard manufacturing from <span class="hlt">tree</span> prunings.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nasser, Ramadan A; Al-Mefarrej, H A; Abdel-Aal, M A; Alshahrani, T S</p> <p>2014-09-01</p> <p>This study investigated the possibility of using the prunings of six locally grown <span class="hlt">tree</span> <span class="hlt">species</span> in Saudi Arabia for cement-bonded particleboard (CBP) production. Panels were made using four different wood particle sizes and a constant wood/cement ratio (1/3 by weight) and target density (1200 kg/m3). The mechanical properties and dimensional stability of the produced panels were determined. The interfacial area and distribution of the wood particles in cement matrix were also investigated by scanning electron microscopy. The results revealed that the panels produced from these pruning materials at a target density of 1200 kg m(-3) meet the strength and dimensional stability requirements of the commercial CBP panels. The mean moduli of rupture and elasticity (MOR and MOE) ranged from 9.68 to 11.78 N mm2 and from 3952 to 5667 N mm2, respectively. The mean percent water absorption for twenty four hours (WA24) ranged from 12.93% to 23.39%. Thickness swelling values ranged from 0.62% to 1.53%. For CBP panels with high mechanical properties and good dimensional stability, mixed-size or coarse particles should be used. Using the <span class="hlt">tree</span> prunings for CBPs production may help to solve the problem of getting rid of these residues by reducing their negative effects on environment, which are caused by poor disposal of such materials through direct combustion process and appearance of black cloud and then the impact on human health or the random accumulation and its indirect effects on the environment. PMID:25204074</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23300786','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23300786"><span id="translatedtitle">Structural and chemical characterization of hardwood from <span class="hlt">tree</span> <span class="hlt">species</span> with applications as bioenergy feedstocks.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cetinkol, Özgül Persil; Smith-Moritz, Andreia M; Cheng, Gang; Lao, Jeemeng; George, Anthe; Hong, Kunlun; Henry, Robert; Simmons, Blake A; Heazlewood, Joshua L; Holmes, Bradley M</p> <p>2012-01-01</p> <p>Eucalypt <span class="hlt">species</span> are a group of flowering <span class="hlt">trees</span> widely used in pulp production for paper manufacture. For several decades, the wood pulp industry has focused research and development efforts on improving yields, growth rates and pulp quality through breeding and the genetic improvement of key <span class="hlt">tree</span> <span class="hlt">species</span>. Recently, this focus has shifted from the production of high quality pulps to the investigation of the use of eucalypts as feedstocks for biofuel production. Here the structure and chemical composition of the heartwood and sapwood of Eucalyptus dunnii, E. globulus, E. pillularis, E. urophylla, an E. urophylla-E. grandis cross, Corymbia citriodora ssp. variegata, and Acacia mangium were compared using nuclear magnetic resonance spectroscopy (NMR), X-ray diffraction (XRD) and biochemical composition analysis. Some trends relating to these compositions were also identified by Fourier transform near infrared (FT-NIR) spectroscopy. These results will serve as a foundation for a more comprehensive database of wood properties that will help develop criteria for the selection of <span class="hlt">tree</span> <span class="hlt">species</span> for use as biorefinery feedstocks. PMID:23300786</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3532498','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3532498"><span id="translatedtitle">Structural and Chemical Characterization of Hardwood from <span class="hlt">Tree</span> <span class="hlt">Species</span> with Applications as Bioenergy Feedstocks</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Çetinkol, Özgül Persil; Smith-Moritz, Andreia M.; Cheng, Gang; Lao, Jeemeng; George, Anthe; Hong, Kunlun; Henry, Robert; Simmons, Blake A.; Heazlewood, Joshua L.; Holmes, Bradley M.</p> <p>2012-01-01</p> <p>Eucalypt <span class="hlt">species</span> are a group of flowering <span class="hlt">trees</span> widely used in pulp production for paper manufacture. For several decades, the wood pulp industry has focused research and development efforts on improving yields, growth rates and pulp quality through breeding and the genetic improvement of key <span class="hlt">tree</span> <span class="hlt">species</span>. Recently, this focus has shifted from the production of high quality pulps to the investigation of the use of eucalypts as feedstocks for biofuel production. Here the structure and chemical composition of the heartwood and sapwood of Eucalyptus dunnii, E. globulus, E. pillularis, E. urophylla, an E. urophylla-E. grandis cross, Corymbia citriodora ssp. variegata, and Acacia mangium were compared using nuclear magnetic resonance spectroscopy (NMR), X-ray diffraction (XRD) and biochemical composition analysis. Some trends relating to these compositions were also identified by Fourier transform near infrared (FT-NIR) spectroscopy. These results will serve as a foundation for a more comprehensive database of wood properties that will help develop criteria for the selection of <span class="hlt">tree</span> <span class="hlt">species</span> for use as biorefinery feedstocks. PMID:23300786</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1059361','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1059361"><span id="translatedtitle">Structural and Chemical Characterization of Hardwood from <span class="hlt">Tree</span> <span class="hlt">Species</span> with Applications as Bioenergy Feedstocks</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Çetinkol, Özgül Persil; Smith-Moritz, Andreia M.; Cheng, Gang; Lao, Jeemeng; George, Anthe; Hong, Kunlun; Henry, Robert; Simmons, Blake A.; Heazlewood, Joshua L.; Holmes, Bradley M.; Zabotina, Olga A.</p> <p>2012-12-28</p> <p>Eucalypt <span class="hlt">species</span> are a group of flowering <span class="hlt">trees</span> widely used in pulp production for paper manufacture. For several decades, the wood pulp industry has focused research and development efforts on improving yields, growth rates and pulp quality through breeding and the genetic improvement of key <span class="hlt">tree</span> <span class="hlt">species</span>. Recently, this focus has shifted from the production of high quality pulps to the investigation of the use of eucalypts as feedstocks for biofuel production. Here the structure and chemical composition of the heartwood and sapwood of Eucalyptus dunnii, E. globulus, E. pillularis, E. urophylla, an E. urophylla-E. grandis cross, Corymbia citriodora ssp. variegata, and Acacia mangium were compared using nuclear magnetic resonance spectroscopy (NMR), X-ray diffraction (XRD) and biochemical composition analysis. Some trends relating to these compositions were also identified by Fourier transform near infrared (FT-NIR) spectroscopy. These results will serve as a foundation for a more comprehensive database of wood properties that will help develop criteria for the selection of <span class="hlt">tree</span> <span class="hlt">species</span> for use as biorefinery feedstocks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27323200','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27323200"><span id="translatedtitle">A comparative framework of the Erythrina velutina <span class="hlt">tree</span> <span class="hlt">species</span> in reforested land and native populations.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Souza, E M S; Pereira, G S; Silva-Mann, R; Álvares-Carvalho, S V; Ferreira, R A</p> <p>2016-01-01</p> <p>Erythrina velutina Willd. (Fabaceae: Papillionoideae) is a pioneer <span class="hlt">species</span> found in tropical and subtropical regions of the world that has medicinal properties and that is used in reforestation projects. This <span class="hlt">species</span> is rare in some areas of northeastern Brazil. This study aimed to characterize and compare genetic structures of natural and restored populations of E. velutina, with a focus on the selection of <span class="hlt">tree</span> seeds. A total of 108 individuals from five natural populations and one restored population were analyzed using ISSR markers, resulting in 407 polymorphic fragments. A high rate of polymorphism was observed in the restored population. The highest genetic variability was identified within populations (82%). Genetic bottleneck tests were significant for the Carmópolis/Rosário do Catete and Laranjeiras natural populations along with the Laranjeiras restored population. Genetic distances significantly correlated with spatial distance. Only the restored population retained unique alleles. Similarly, increased genetic distance was observed in individuals of the restored populations compared to the other populations. Observed genetic variation in both natural and restored populations of E. velutina was moderate, thus enabling selection of divergent <span class="hlt">trees</span> from those <span class="hlt">trees</span> supplying seeds. Environmental protection and management of these areas is necessary for the maintenance of these individuals and subsequent reproduction. We recommend suggestions for E. velutina conservation, since the restoration model adopted in this study did not promote the development of the specimens until the reproductive stage in a fashion that aims to augment the soil seed bank supply, as is suggested for pioneer <span class="hlt">species</span>. PMID:27323200</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013BGD....1011037L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013BGD....1011037L"><span id="translatedtitle">Soil greenhouse gas fluxes from different <span class="hlt">tree</span> <span class="hlt">species</span> on Taihang Mountain, North China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, X. P.; Zhang, W. J.; Hu, C. S.; Tang, X. G.</p> <p>2013-07-01</p> <p>The objectives of this study were to investigate seasonal variation of greenhouse gas fluxes from soils on sites dominated by plantation (Robinia pseudoacacia, Punica granatum, and Ziziphus jujube) and natural regenerated forests (Vitex negundo var. heterophylla, Leptodermis oblonga, and Bothriochloa ischcemum), and to identify how <span class="hlt">tree</span> <span class="hlt">species</span>, litter exclusion, and soil properties (soil temperature, soil moisture, soil organic carbon, total N, soil bulk density, and soil pH) explained the temporal and spatial variance in soil greenhouse gas fluxes. Fluxes of greenhouse gases were measured using static chamber and gas chromatography techniques. Six static chambers were randomly installed in each <span class="hlt">tree</span> <span class="hlt">species</span>. Three chambers were randomly designated to measure the impacts of surface litter exclusion, and the remaining three were used as a control. Field measurements were conducted biweekly from May 2010 through April 2012. Soil CO2 emissions from all <span class="hlt">tree</span> <span class="hlt">species</span> were significantly affected by soil temperature, soil moisture, and their interaction. Driven by the seasonality of temperature and precipitation, soil CO2 emissions demonstrated a clear seasonal pattern, with fluxes significantly higher during the rainy season than during the dry season. Soil CH4 and N2O fluxes were not significantly correlated with soil temperature, soil moisture, or their interaction, and no significant seasonal differences were detected. Soil CO2 and N2O fluxes were significantly correlated with soil organic carbon, total N, and soil bulk density, while soil pH was not correlated with CO2 and N2O emissions. Soil CH4 fluxes did not display pronounced dependency on soil organic carbon, total N, soil bulk density, and soil pH. Removal of surface litter resulted in significant decreases in CO2 emissions and CH4 uptakes, but had no significant influence on N2O fluxes. Soils in six <span class="hlt">tree</span> <span class="hlt">species</span> acted as sinks for atmospheric CH4. With the exception of Ziziphus jujube, Soils in all sites</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..1410046C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..1410046C"><span id="translatedtitle">Chemical composition and fuel wood characteristics of fast growing <span class="hlt">tree</span> <span class="hlt">species</span> in India</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chauhan, S. K.; Soni, R.</p> <p>2012-04-01</p> <p>India is one of the growing economy in the world and energy is a critical input to sustain the growth of development. Country aims at security and efficiency of energy. Though fossil fuel will continue to play a dominant role in energy scenario but country is committed to global environmental well being thus stressing on environment friendly technologies. Concerns of energy security in this changing climatic situation have led to increasing support for the development of new renewable source of energy. Government though is determined to facilitate bio-energy and many projects have been established but initial after-affects more specifically on the domestic fuelwood are evident. Even the biomass power generating units are facing biomass crisis and accordingly the prices are going up. The CDM projects are supporting the viability of these units resultantly the Indian basket has a large number of biomass projects (144 out of total 506 with 28 per cent CERs). The use for fuelwood as a primary source of energy for domestic purpose by the poor people (approx. 80 per cent) and establishment of bio-energy plants may lead to deforestation to a great extent and only solution to this dilemma is to shift the wood harvest from the natural forests to energy plantations. However, there is conspicuous lack of knowledge with regards to the fuelwood characteristics of fast growing <span class="hlt">tree</span> <span class="hlt">species</span> for their selection for energy plantations. The calorific value of the <span class="hlt">species</span> is important criteria for selection for fuel but it is affected by the proportions of biochemical constituents present in them. The aim of the present work was to study the biomass production, calorific value and chemical composition of different short rotation <span class="hlt">tree</span> <span class="hlt">species</span>. The study was done from the perspective of using the fast growing <span class="hlt">tree</span> <span class="hlt">species</span> for energy production at short rotation and the study concluded that short rotation <span class="hlt">tree</span> <span class="hlt">species</span> like Gmelina arborea, Eucalyptus tereticornis, Pongamia pinnata</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4383566','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4383566"><span id="translatedtitle">The Effects of Drought and Shade on the Performance, Morphology and Physiology of Ghanaian <span class="hlt">Tree</span> <span class="hlt">Species</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Amissah, Lucy; Mohren, Godefridus M. J.; Kyereh, Boateng; Poorter, Lourens</p> <p>2015-01-01</p> <p>In tropical forests light and water availability are the most important factors for seedling growth and survival but an increasing frequency of drought may affect <span class="hlt">tree</span> regeneration. One central question is whether drought and shade have interactive effects on seedling growth and survival. Here, we present results of a greenhouse experiment, in which seedlings of 10 Ghanaian <span class="hlt">tree</span> <span class="hlt">species</span> were exposed to combinations of strong seasonal drought (continuous watering versus withholding water for nine weeks) and shade (5% irradiance versus 20% irradiance). We evaluated the effects of drought and shade on seedling survival and growth and plasticity of 11 underlying traits related to biomass allocation, morphology and physiology. Seedling survival under dry conditions was higher in shade than in high light, thus providing support for the “facilitation hypothesis” that shade enhances plant performance through improved microclimatic conditions, and rejecting the trade-off hypothesis that drought should have stronger impact in shade because of reduced root investment. Shaded plants had low biomass fraction in roots, in line with the trade-off hypothesis, but they compensated for this with a higher specific root length (i.e., root length per unit root mass), resulting in a similar root length per plant mass and, hence, similar water uptake capacity as high-light plants. The majority (60%) of traits studied responded independently to drought and shade, indicating that within <span class="hlt">species</span> shade- and drought tolerances are not in trade-off, but largely uncoupled. When individual <span class="hlt">species</span> responses were analysed, then for most of the traits only one to three <span class="hlt">species</span> showed significant interactive effects between drought and shade. The uncoupled response of most <span class="hlt">species</span> to drought and shade should provide ample opportunity for niche differentiation and <span class="hlt">species</span> coexistence under a range of water and light conditions. Overall our greenhouse results suggest that, in the absence of root</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25836337','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25836337"><span id="translatedtitle">The effects of drought and shade on the performance, morphology and physiology of Ghanaian <span class="hlt">tree</span> <span class="hlt">species</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Amissah, Lucy; Mohren, Godefridus M J; Kyereh, Boateng; Poorter, Lourens</p> <p>2015-01-01</p> <p>In tropical forests light and water availability are the most important factors for seedling growth and survival but an increasing frequency of drought may affect <span class="hlt">tree</span> regeneration. One central question is whether drought and shade have interactive effects on seedling growth and survival. Here, we present results of a greenhouse experiment, in which seedlings of 10 Ghanaian <span class="hlt">tree</span> <span class="hlt">species</span> were exposed to combinations of strong seasonal drought (continuous watering versus withholding water for nine weeks) and shade (5% irradiance versus 20% irradiance). We evaluated the effects of drought and shade on seedling survival and growth and plasticity of 11 underlying traits related to biomass allocation, morphology and physiology. Seedling survival under dry conditions was higher in shade than in high light, thus providing support for the "facilitation hypothesis" that shade enhances plant performance through improved microclimatic conditions, and rejecting the trade-off hypothesis that drought should have stronger impact in shade because of reduced root investment. Shaded plants had low biomass fraction in roots, in line with the trade-off hypothesis, but they compensated for this with a higher specific root length (i.e., root length per unit root mass), resulting in a similar root length per plant mass and, hence, similar water uptake capacity as high-light plants. The majority (60%) of traits studied responded independently to drought and shade, indicating that within <span class="hlt">species</span> shade- and drought tolerances are not in trade-off, but largely uncoupled. When individual <span class="hlt">species</span> responses were analysed, then for most of the traits only one to three <span class="hlt">species</span> showed significant interactive effects between drought and shade. The uncoupled response of most <span class="hlt">species</span> to drought and shade should provide ample opportunity for niche differentiation and <span class="hlt">species</span> coexistence under a range of water and light conditions. Overall our greenhouse results suggest that, in the absence of root</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1964803','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1964803"><span id="translatedtitle">Crown Plasticity and Competition for Canopy Space: A New Spatially Implicit Model Parameterized for 250 North American <span class="hlt">Tree</span> <span class="hlt">Species</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Purves, Drew W.; Lichstein, Jeremy W.; Pacala, Stephen W.</p> <p>2007-01-01</p> <p>Background Canopy structure, which can be defined as the sum of the sizes, shapes and relative placements of the <span class="hlt">tree</span> crowns in a forest stand, is central to all aspects of forest ecology. But there is no accepted method for deriving canopy structure from the sizes, <span class="hlt">species</span> and biomechanical properties of the individual <span class="hlt">trees</span> in a stand. Any such method must capture the fact that <span class="hlt">trees</span> are highly plastic in their growth, forming tessellating crown shapes that fill all or most of the canopy space. Methodology/Principal Findings We introduce a new, simple and rapidly-implemented model–the Ideal <span class="hlt">Tree</span> Distribution, ITD–with <span class="hlt">tree</span> form (height allometry and crown shape), growth plasticity, and space-filling, at its core. The ITD predicts the canopy status (in or out of canopy), crown depth, and total and exposed crown area of the <span class="hlt">trees</span> in a stand, given their <span class="hlt">species</span>, sizes and potential crown shapes. We use maximum likelihood methods, in conjunction with data from over 100,000 <span class="hlt">trees</span> taken from forests across the coterminous US, to estimate ITD model parameters for 250 North American <span class="hlt">tree</span> <span class="hlt">species</span>. With only two free parameters per species–one aggregate parameter to describe crown shape, and one parameter to set the so-called depth bias–the model captures between-<span class="hlt">species</span> patterns in average canopy status, crown radius, and crown depth, and within-<span class="hlt">species</span> means of these metrics vs stem diameter. The model also predicts much of the variation in these metrics for a <span class="hlt">tree</span> of a given <span class="hlt">species</span> and size, resulting solely from deterministic responses to variation in stand structure. Conclusions/Significance This new model, with parameters for US <span class="hlt">tree</span> <span class="hlt">species</span>, opens up new possibilities for understanding and modeling forest dynamics at local and regional scales, and may provide a new way to interpret remote sensing data of forest canopies, including LIDAR and aerial photography. PMID:17849000</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25424149','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25424149"><span id="translatedtitle">Heterogeneity in soil water and light environments and dispersal limitation: what facilitates <span class="hlt">tree</span> <span class="hlt">species</span> coexistence in a temperate forest?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Masaki, T; Hata, S; Ide, Y</p> <p>2015-03-01</p> <p>In the present study, we analysed the habitat association of <span class="hlt">tree</span> <span class="hlt">species</span> in an old-growth temperate forest across all life stages to test theories on the coexistence of <span class="hlt">tree</span> <span class="hlt">species</span> in forest communities. An inventory for <span class="hlt">trees</span> was implemented at a 6-ha plot in Ogawa Forest Reserve for adults, juveniles, saplings and seedlings. Volumetric soil water content (SMC) and light levels were measured in 10-m grids. Relationships between the actual number of stems and environmental variables were determined for 35 major <span class="hlt">tree</span> <span class="hlt">species</span>, and the spatial correlations within and among <span class="hlt">species</span> were analysed. The light level had no statistically significant effect on distribution of saplings and seedlings of any <span class="hlt">species</span>. In contrast, most <span class="hlt">species</span> had specific optimal values along the SMC gradient. The optimal values were almost identical in earlier life stages, but were more variable in later life stages among <span class="hlt">species</span>. However, no effective niche partitioning among the <span class="hlt">species</span> was apparent even at the adult stage. Furthermore, results of spatial analyses suggest that dispersal limitation was not sufficient to mitigate competition between <span class="hlt">species</span>. This might result from well-scattered seed distribution via wind and bird dispersal, as well as conspecific density-dependent mortality of seeds and seedlings. Thus, both niche partitioning and dispersal limitation appeared less important for facilitating coexistence of <span class="hlt">species</span> within this forest than expected in tropical forests. The <span class="hlt">tree</span> <span class="hlt">species</span> assembly in this temperate forest might be controlled through a neutral process at the spatial scale tested in this study. PMID:25424149</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005AGUSMNB22F..03S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005AGUSMNB22F..03S&link_type=ABSTRACT"><span id="translatedtitle">The Role of Native <span class="hlt">Tree</span> <span class="hlt">Species</span> on Leaf Breakdown Dynamics of the Invasive <span class="hlt">Tree</span> of Heaven ( Ailanthus altissima) in an Urban Stream</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Swan, C.; Healey, B.</p> <p>2005-05-01</p> <p>Anthropogenic disturbance of ecosystem processes is increasingly being explored in urban settings. One profound impact is the striking increase in the distribution of invasive plant <span class="hlt">species</span>. For example, <span class="hlt">Tree</span> of Heaven (Ailanthus altissima, TOH), introduced into the U.S. from Asia in 1784, is a successful colonist of recently deforested habitats. As a result, remnant patches in urban ecosystems have become overrun with this <span class="hlt">tree</span> <span class="hlt">species</span>, excluding native <span class="hlt">species</span> via fast growth and allelopathy. While suffering from human-induced degradation, urban streams still support food webs that function to process riparian-derived organic matter (e.g., leaves, wood). The purpose of this study was to (1) estimate leaf litter breakdown of native <span class="hlt">tree</span> leaves and those of TOH in an urban stream, (2) study the detritivore feeding rate of the same leaf <span class="hlt">species</span>, and (3) determine if increasing native <span class="hlt">species</span> richness of leaf litter can alter breakdown of TOH leaves. Field manipulations of leaf pack composition were done in a highly urbanized stream (>30% upstream urban land use) in Baltimore County, Maryland, USA. This was complimented by a series of laboratory feeding experiments employing similar leaf treatments and local shredding invertebrate taxa. Breakdown of TOH alone was extremely rapid, significantly exceeding that of all native <span class="hlt">tree</span> <span class="hlt">species</span> employed. Furthermore, mixing TOH with native <span class="hlt">tree</span> <span class="hlt">species</span>, red maple and white oak, substantially reduced TOH decay compared to decay of TOH alone. However, supporting laboratory studies showed that TOH was a preferred resource by shredding invertebrates over all native <span class="hlt">species</span>. Subsequent analysis of the structural integrity of all leaf <span class="hlt">species</span> revealed that TOH was the least resistant to force, possibly explaining the counterintuitive decrease of TOH decay in mixtures. We interpret this as meaning the stream invertebrates, while preferring to consume TOH, appeared not to influence TOH decay in mixtures with native <span class="hlt">species</span>. Instead</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3612601','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3612601"><span id="translatedtitle"><span class="hlt">Species</span> distributions in response to individual soil nutrients and seasonal drought across a community of tropical <span class="hlt">trees</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Condit, Richard; Engelbrecht, Bettina M. J.; Pino, Delicia; Pérez, Rolando; Turner, Benjamin L.</p> <p>2013-01-01</p> <p>Tropical forest vegetation is shaped by climate and by soil, but understanding how the distributions of individual <span class="hlt">tree</span> <span class="hlt">species</span> respond to specific resources has been hindered by high diversity and consequent rarity. To study <span class="hlt">species</span> over an entire community, we surveyed <span class="hlt">trees</span> and measured soil chemistry across climatic and geological gradients in central Panama and then used a unique hierarchical model of <span class="hlt">species</span> occurrence as a function of rainfall and soil chemistry to circumvent analytical difficulties posed by rare <span class="hlt">species</span>. The results are a quantitative assessment of the responses of 550 <span class="hlt">tree</span> <span class="hlt">species</span> to eight environmental factors, providing a measure of the importance of each factor across the entire <span class="hlt">tree</span> community. Dry-season intensity and soil phosphorus were the strongest predictors, each affecting the distribution of more than half of the <span class="hlt">species</span>. Although we anticipated clear-cut responses to dry-season intensity, the finding that many <span class="hlt">species</span> have pronounced associations with either high or low phosphorus reveals a previously unquantified role for this nutrient in limiting tropical <span class="hlt">tree</span> distributions. The results provide the data necessary for understanding distributional limits of <span class="hlt">tree</span> <span class="hlt">species</span> and predicting future changes in forest composition. PMID:23440213</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4686666','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4686666"><span id="translatedtitle">The effect of soil-borne pathogens depends on the abundance of host <span class="hlt">tree</span> <span class="hlt">species</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Liu, Yu; Fang, Suqin; Chesson, Peter; He, Fangliang</p> <p>2015-01-01</p> <p>The overarching issue for understanding biodiversity maintenance is how fitness advantages accrue to a <span class="hlt">species</span> as it becomes rare, as this is the defining feature of stable coexistence mechanisms. Without these fitness advantages, average fitness differences between <span class="hlt">species</span> will lead to exclusion. However, empirical evidence is lacking, especially for forests, due to the difficulty of manipulating density on a large-enough scale. Here we took advantage of naturally occurring contrasts in abundance between sites of a subtropical <span class="hlt">tree</span> <span class="hlt">species</span>, Ormosia glaberrima, to demonstrate how low-density fitness advantages accrue by the Janzen–Connell mechanism. The results showed that soil pathogens suppressed seedling recruitment of O. glaberrima when it is abundant but had little effect on the seedlings when it is at low density due to the lack of pathogens. The difference in seedling survival between abundant and low-density sites demonstrates strong dependence of pathogenic effect on the abundance of host <span class="hlt">species</span>. PMID:26632594</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26632594','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26632594"><span id="translatedtitle">The effect of soil-borne pathogens depends on the abundance of host <span class="hlt">tree</span> <span class="hlt">species</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Yu; Fang, Suqin; Chesson, Peter; He, Fangliang</p> <p>2015-01-01</p> <p>The overarching issue for understanding biodiversity maintenance is how fitness advantages accrue to a <span class="hlt">species</span> as it becomes rare, as this is the defining feature of stable coexistence mechanisms. Without these fitness advantages, average fitness differences between <span class="hlt">species</span> will lead to exclusion. However, empirical evidence is lacking, especially for forests, due to the difficulty of manipulating density on a large-enough scale. Here we took advantage of naturally occurring contrasts in abundance between sites of a subtropical <span class="hlt">tree</span> <span class="hlt">species</span>, Ormosia glaberrima, to demonstrate how low-density fitness advantages accrue by the Janzen-Connell mechanism. The results showed that soil pathogens suppressed seedling recruitment of O. glaberrima when it is abundant but had little effect on the seedlings when it is at low density due to the lack of pathogens. The difference in seedling survival between abundant and low-density sites demonstrates strong dependence of pathogenic effect on the abundance of host <span class="hlt">species</span>. PMID:26632594</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27146334','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27146334"><span id="translatedtitle">A test of the hydraulic vulnerability segmentation hypothesis in angiosperm and conifer <span class="hlt">tree</span> <span class="hlt">species</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Johnson, Daniel M; Wortemann, Remi; McCulloh, Katherine A; Jordan-Meille, Lionel; Ward, Eric; Warren, Jeffrey M; Palmroth, Sari; Domec, Jean-Christophe</p> <p>2016-08-01</p> <p>Water transport from soils to the atmosphere is critical for plant growth and survival. However, we have a limited understanding about many portions of the whole-<span class="hlt">tree</span> hydraulic pathway, because the vast majority of published information is on terminal branches. Our understanding of mature <span class="hlt">tree</span> trunk hydraulic physiology, in particular, is limited. The hydraulic vulnerability segmentation hypothesis (HVSH) stipulates that distal portions of the plant (leaves, branches and roots) should be more vulnerable to embolism than trunks, which are nonredundant organs that require a massive carbon investment. In the current study, we compared vulnerability to loss of hydraulic function, leaf and xylem water potentials and the resulting hydraulic safety margins (in relation to the water potential causing 50% loss of hydraulic conductivity) in leaves, branches, trunks and roots of four angiosperms and four conifer <span class="hlt">tree</span> <span class="hlt">species</span>. Across all <span class="hlt">species</span>, our results supported strongly the HVSH as leaves and roots were less resistant to embolism than branches or trunks. However, branches were consistently more resistant to embolism than any other portion of the plant, including trunks. Also, calculated whole-<span class="hlt">tree</span> vulnerability to hydraulic dysfunction was much greater than vulnerability in branches. This was due to hydraulic dysfunction in roots and leaves at less negative water potentials than those causing branch or trunk dysfunction. Leaves and roots had narrow or negative hydraulic safety margins, but trunks and branches maintained positive safety margins. By using branch-based hydraulic information as a proxy for entire plants, much research has potentially overestimated embolism resistance, and possibly drought tolerance, for many <span class="hlt">species</span>. This study highlights the necessity to reconsider past conclusions made about plant resistance to drought based on branch xylem only. This study also highlights the necessity for more research of whole-plant hydraulic physiology to better</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27262582','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27262582"><span id="translatedtitle">Light-exposed shoots of seven coexisting deciduous <span class="hlt">species</span> show common photosynthetic responses to <span class="hlt">tree</span> height.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Miyata, Rie; Kohyama, Takashi S</p> <p>2016-10-01</p> <p>Functional traits of light-exposed leaves have been reported to show <span class="hlt">tree</span> height-dependent change. However, it remains unknown how plastic response of leaf traits to <span class="hlt">tree</span> height is linked with shoot-level carbon gain. To answer this question, we examined the photosynthetic properties of fully lit current-year shoots in crown tops with various heights for seven deciduous broad-leaved <span class="hlt">species</span> dominated in a cool-temperate forest in northern Japan. We measured leaf mass, stomatal conductance, nitrogen content, light-saturated net photosynthetic rate (all per leaf lamina area), foliar stable carbon isotope ratio, and shoot mass allocation to leaf laminae. We employed hierarchical Bayesian models to simultaneously quantify inter-trait relationships for all <span class="hlt">species</span>. We found that leaf and shoot traits were co-varied in association with height, and that there was no quantitative inter-specific difference in leaf- and shoot-level plastic responses to height. Nitrogen content increased and stomatal conductance decreased with height. Reflecting these antagonistic responses to height, photosynthetic rate was almost unchanged with height. Photosynthetic rate divided by stomatal conductance as a proxy of photosynthetic water use efficiency sufficiently explained the variation of foliar carbon isotope ratio. The increase in mass allocation to leaves in a shoot compensated for the height-dependent decline in photosynthetic rate per leaf lamina mass. Consequently, photosynthetic gain at the scale of current-year shoot mass was kept unchanged with <span class="hlt">tree</span> height. We suggest that the convergent responses of shoot functional traits across <span class="hlt">species</span> reflect common requirements for <span class="hlt">trees</span> coexisting in a forest. PMID:27262582</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=dogmatism&pg=3&id=EJ306380','ERIC'); return false;" href="http://eric.ed.gov/?q=dogmatism&pg=3&id=EJ306380"><span id="translatedtitle"><span class="hlt">Alienation</span>, Dogmatism and Acquiescence.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Ray, John J.</p> <p>1984-01-01</p> <p>Examined the issue of acquiescence by administering a balanced dogmatism scale and a balanced <span class="hlt">alienation</span> scale to a random sample of Australians (N=118). Results showed that dogmatism and <span class="hlt">alienation</span> did not correlate when acquiescence was controlled. (LLL)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70033546','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70033546"><span id="translatedtitle">The effects of flooding and sedimentation on seed germination of two bottomland hardwood <span class="hlt">tree</span> <span class="hlt">species</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Pierce, A.R.; King, S.L.</p> <p>2007-01-01</p> <p>Flooding and sedimentation are two of the dominant disturbances that influence <span class="hlt">tree</span> <span class="hlt">species</span> composition and succession in floodplain forests. The importance of these disturbances may be most notable during the germination and establishment phases of plant succession. Channelization of most alluvial systems in the southeastern United States has caused dramatic and systematic alterations to both hydrologic and sedimentation processes of floodplain systems. We determined the influence of these altered abiotic processes on the germination and growth of two common floodplain <span class="hlt">tree</span> <span class="hlt">species</span>: swamp chestnut oak (Quercus michauxii Nutt.) and overcup oak (Q. lyrata Walt.). Flood durations of 0 days, 15 days, and 30 days prior to germination was a factor in germination, but the effect varied by <span class="hlt">species</span>. For instance, ovcrcup oak, which has a higher tolerance to flooding than swamp chestnut oak, had higher germination rates in the flooded treatments (15-day x?? = 78% and 30-day x?? = 85%) compared to the non-flooded treatment (x?? = 54%). In contrast, germination rates of swamp chestnut oak were negatively affected by the 30-day flood treatment. Sediment deposition rates of 2 cm of top soil, 2 cm of sand, and 8 cm of sand also affected germination, but were secondary to flood duration. The main effect of the sediment treatment in this experiment was a reduction in above-ground height of seedlings. Our study provides evidence for the importance of both flooding and sedimentation in determining <span class="hlt">tree</span> <span class="hlt">species</span> composition in floodplain systems, and that tolerance levels to such stressors vary by <span class="hlt">species</span>. ?? 2007, The Society of Wetland Scientists.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013AIPC.1571..302N&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013AIPC.1571..302N&link_type=ABSTRACT"><span id="translatedtitle">Community structure, diversity and total biomass of <span class="hlt">tree</span> <span class="hlt">species</span> at Kapur dominated forests in Peninsular Malaysia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Norafida, N. A. Nik; Nizam, M. S.; Juliana, W. A. Wan</p> <p>2013-11-01</p> <p>A study was conducted to determine the <span class="hlt">species</span> composition, diversity and biomass of Kapur (Dryobalanops aromatica Gaertn.f.) dominated forests in Peninsular Malaysia. Three forests were selected in different geographical zones, namely Bukit Bauk Virgin Jungle Reserve (BBVJR), Terengganu, Lesong Forest Reserve (LFR), Pahang and Gunung Belumut Recreational Forest (GBRF), Johor. Thirty plots of 0.1 ha (50 m × 20 m) were established with a total sampling area of 1.0 ha at each forest site. All <span class="hlt">trees</span> with ≥5 cm diameter at breast height (dbh) were tagged, measured and voucher specimens were collected. Floristic composition in the study plot at BBVJR recorded 55 families, 147 genera and 336 <span class="hlt">species</span>. In LFR, there were 52 families, 138 genera and 288 <span class="hlt">species</span>, whereas in GBRF there were 52 families, 132 genera and 271 <span class="hlt">species</span>. D. aromatica was the most important <span class="hlt">species</span> in all study plots with the Importance Value Index (IVi) of 17.81%, 23.01% and 16.25% in BBVJR, LFR and GBRF, respectively. Similar trend at family level showed the Dipterocarpaceae was the most important family in each of the areas with the family Importance Value Index (FIVi) of 27.95% (BBVJR), 26.09% (LFR) and 27.16% (GBRF). Shannon diversity index (H'f) and Shannon evenness index (J'f) of <span class="hlt">trees</span> at BBVJR was 5.02 and 0.86; LFR was 4.63 and 0.82; and GBRF was 4.82 and 0.86, respectively. Sorensen's community similarity coefficient (CCs) showed that <span class="hlt">tree</span> communities between BBVJR, LFR and GBRF had low similarities with values of 0.3 to 0.4. The highest total biomass estimated was in LFR with a value of 739.44 t/ha, followed by BBVJR at 701.34 t/ha and GBRF at 606.29 t/ha.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4561634','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4561634"><span id="translatedtitle">Environmental correlates for <span class="hlt">tree</span> occurrences, <span class="hlt">species</span> distribution and richness on a high-elevation tropical island</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Birnbaum, Philippe; Ibanez, Thomas; Pouteau, Robin; Vandrot, Hervé; Hequet, Vanessa; Blanchard, Elodie; Jaffré, Tanguy</p> <p>2015-01-01</p> <p>High-elevation tropical islands are ideally suited for examining the factors that determine <span class="hlt">species</span> distribution, given the complex topographies and climatic gradients that create a wide variety of habitats within relatively small areas. New Caledonia, a megadiverse Pacific archipelago, has long focussed the attention of botanists working on the spatial and environmental ranges of specific groups, but few studies have embraced the entire <span class="hlt">tree</span> flora of the archipelago. In this study we analyse the distribution of 702 native <span class="hlt">species</span> of rainforest <span class="hlt">trees</span> of New Caledonia, belonging to 195 genera and 80 families, along elevation and rainfall gradients on ultramafic (UM) and non-ultramafic (non-UM) substrates. We compiled four complementary data sources: (i) herbarium specimens, (ii) plots, (iii) photographs and (iv) observations, totalling 38 936 unique occurrences distributed across the main island. Compiled into a regular 1-min grid (1.852 × 1.852 km), this dataset covered ∼22 % of the island. The studied rainforest <span class="hlt">species</span> exhibited high environmental tolerance; 56 % of them were not affiliated to a substrate type and they exhibited wide elevation (average 891 ± 332 m) and rainfall (average 2.2 ± 0.8 m year−1) ranges. Conversely their spatial distribution was highly aggregated, which suggests dispersal limitation. The observed <span class="hlt">species</span> richness was driven mainly by the density of occurrences. However, at the highest elevations or rainfalls, and particularly on UM, the observed richness tends to be lower, independently of the sampling effort. The study highlights the imbalance of the dataset in favour of higher values of rainfall and of elevation. Projected onto a map, under-represented areas are a guide as to where future sampling efforts are most required to complete our understanding of rainforest <span class="hlt">tree</span> <span class="hlt">species</span> distribution. PMID:26162898</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26162898','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26162898"><span id="translatedtitle">Environmental correlates for <span class="hlt">tree</span> occurrences, <span class="hlt">species</span> distribution and richness on a high-elevation tropical island.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Birnbaum, Philippe; Ibanez, Thomas; Pouteau, Robin; Vandrot, Hervé; Hequet, Vanessa; Blanchard, Elodie; Jaffré, Tanguy</p> <p>2015-01-01</p> <p>High-elevation tropical islands are ideally suited for examining the factors that determine <span class="hlt">species</span> distribution, given the complex topographies and climatic gradients that create a wide variety of habitats within relatively small areas. New Caledonia, a megadiverse Pacific archipelago, has long focussed the attention of botanists working on the spatial and environmental ranges of specific groups, but few studies have embraced the entire <span class="hlt">tree</span> flora of the archipelago. In this study we analyse the distribution of 702 native <span class="hlt">species</span> of rainforest <span class="hlt">trees</span> of New Caledonia, belonging to 195 genera and 80 families, along elevation and rainfall gradients on ultramafic (UM) and non-ultramafic (non-UM) substrates. We compiled four complementary data sources: (i) herbarium specimens, (ii) plots, (iii) photographs and (iv) observations, totalling 38 936 unique occurrences distributed across the main island. Compiled into a regular 1-min grid (1.852 × 1.852 km), this dataset covered ∼22 % of the island. The studied rainforest <span class="hlt">species</span> exhibited high environmental tolerance; 56 % of them were not affiliated to a substrate type and they exhibited wide elevation (average 891 ± 332 m) and rainfall (average 2.2 ± 0.8 m year(-1)) ranges. Conversely their spatial distribution was highly aggregated, which suggests dispersal limitation. The observed <span class="hlt">species</span> richness was driven mainly by the density of occurrences. However, at the highest elevations or rainfalls, and particularly on UM, the observed richness tends to be lower, independently of the sampling effort. The study highlights the imbalance of the dataset in favour of higher values of rainfall and of elevation. Projected onto a map, under-represented areas are a guide as to where future sampling efforts are most required to complete our understanding of rainforest <span class="hlt">tree</span> <span class="hlt">species</span> distribution. PMID:26162898</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25220499','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25220499"><span id="translatedtitle">Chemical taxonomy of <span class="hlt">tree</span> peony <span class="hlt">species</span> from China based on root cortex metabolic fingerprinting.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>He, Chunnian; Peng, Bing; Dan, Yang; Peng, Yong; Xiao, Peigen</p> <p>2014-11-01</p> <p>The section Moutan of the genus Paeonia consists of eight <span class="hlt">species</span> that are confined to a small area in China. A wide range of metabolites, including monoterpenoid glucosides, flavonoids, tannins, stilbenes, triterpenoids, steroids, paeonols, and phenols, have been found in the <span class="hlt">species</span> belonging to section Moutan. However, although previous studies have analyzed the metabolites found in these <span class="hlt">species</span>, the metabolic similarities that can be used for the chemotaxonomic distinction of section Moutan <span class="hlt">species</span> are not yet clear. In this study, HPLC-DAD-based metabolic fingerprinting was applied to the classification of eight <span class="hlt">species</span>: Paeoniasuffruticosa, Paeoniaqiui, Paeoniaostii, Paeoniarockii, Paeoniajishanensis, Paeoniadecomposita, Paeoniadelavayi, and Paeonialudlowii. In total, of the 47 peaks that exhibited an occurrence frequency of 75% in all 23 <span class="hlt">tree</span> peony samples, 43 of these metabolites were identified according to their retention times and UV absorption spectra, together with combined HPLC-QTOF-MS. These data were compared with reference standard compounds. The 43 isolated compounds included 17 monoterpenoid glucosides, 11 galloyl glucoses, 5 flavonoids, 6 paeonols and 4 phenols. Principal component analysis (PCA), and hierarchical cluster analysis (HCA), showed a clear separation between the <span class="hlt">species</span> based on metabolomics similarities and four groups were identified. The results exhibited good agreement with the classical classification based on the morphological characteristics and geographical distributions of the subsections Vaginatae F.C. Stern and Delavayanae F.C. Stern with the exception of P. decomposita, which was found to be a transition <span class="hlt">species</span> between these two subsections. According to their metabolic fingerprinting characteristics, P. ostii and P. suffruticosa can be considered one <span class="hlt">species</span>, and this result is consistent with the viewpoint of medicinal plant scientists but different from that of classical morphological processing. Significantly large</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26438447','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26438447"><span id="translatedtitle">Patchy Invasion of Stage-Structured <span class="hlt">Alien</span> <span class="hlt">Species</span> with Short-Distance and Long-Distance Dispersal.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rodrigues, Luiz Alberto Díaz; Mistro, Diomar Cristina; Cara, Elisa Regina; Petrovskaya, Natalia; Petrovskii, Sergei</p> <p>2015-08-01</p> <p>Understanding of spatiotemporal patterns arising in invasive <span class="hlt">species</span> spread is necessary for successful management and control of harmful <span class="hlt">species</span>, and mathematical modeling is widely recognized as a powerful research tool to achieve this goal. The conventional view of the typical invasion pattern as a continuous population traveling front has been recently challenged by both empirical and theoretical results revealing more complicated, alternative scenarios. In particular, the so-called patchy invasion has been a focus of considerable interest; however, its theoretical study was restricted to the case where the invasive <span class="hlt">species</span> spreads by predominantly short-distance dispersal. Meanwhile, there is considerable evidence that the long-distance dispersal is not an exotic phenomenon but a strategy that is used by many <span class="hlt">species</span>. In this paper, we consider how the patchy invasion can be modified by the effect of the long-distance dispersal and the effect of the fat tails of the dispersal kernels. PMID:26438447</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4070915','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4070915"><span id="translatedtitle">Leaf Phenological Characters of Main <span class="hlt">Tree</span> <span class="hlt">Species</span> in Urban Forest of Shenyang</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Xu, Sheng; Xu, Wenduo; Chen, Wei; He, Xingyuan; Huang, Yanqing; Wen, Hua</p> <p>2014-01-01</p> <p>Background Plant leaves, as the main photosynthetic organs and the high energy converters among primary producers in terrestrial ecosystems, have attracted significant research attention. Leaf lifespan is an adaptive characteristic formed by plants to obtain the maximum carbon in the long-term adaption process. It determines important functional and structural characteristics exhibited in the environmental adaptation of plants. However, the leaf lifespan and leaf characteristics of urban forests were not studied up to now. Methods By using statistic, linear regression methods and correlation analysis, leaf phenological characters of main <span class="hlt">tree</span> <span class="hlt">species</span> in urban forest of Shenyang were observed for five years to obtain the leafing phenology (including leafing start time, end time, and duration), defoliating phenology (including defoliation start time, end time, and duration), and the leaf lifespan of the main <span class="hlt">tree</span> <span class="hlt">species</span>. Moreover, the relationships between temperature and leafing phenology, defoliating phenology, and leaf lifespan were analyzed. Findings The timing of leafing differed greatly among <span class="hlt">species</span>. The early leafing <span class="hlt">species</span> would have relatively early end of leafing; the longer it took to the end of leafing would have a later time of completed leafing. The timing of defoliation among different <span class="hlt">species</span> varied significantly, the early defoliation <span class="hlt">species</span> would have relatively longer duration of defoliation. If the mean temperature rise for 1°C in spring, the time of leafing would experience 5 days earlier in spring. If the mean temperature decline for 1°C, the time of defoliation would experience 3 days delay in autumn. Interpretation There is significant correlation between leaf longevity and the time of leafing and defoliation. According to correlation analysis and regression analysis, there is significant correlation between temperature and leafing and defoliation phenology. Early leafing <span class="hlt">species</span> would have a longer life span and consequently have</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21774305','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21774305"><span id="translatedtitle">[Dynamic changes of dominant <span class="hlt">tree</span> <span class="hlt">species</span> in broad-leaved Korean pine forest at different succession stages in Changbai Mountains].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Guo, Li-ping; Ji, Lan-zhu; Wang, Zhen; Wang, Zhi-xuan</p> <p>2011-04-01</p> <p>Taking the broad-leaved Korean pine forest stands at four different succession stages after clear-cutting in Changbai Mountains as test objects, this paper studied the change characteristics of community composition and dominant <span class="hlt">species</span>. The <span class="hlt">tree</span> <span class="hlt">species</span> richness, Shannon diversity index, and Simpson dominance index at different succession stages had less change, but the evenness and abundance changed greatly. As succession progressed, the community composition changed constantly, i.e., <span class="hlt">species</span> number decreased, while the basal area sum and the maximum importance value of dominant <span class="hlt">tree</span> <span class="hlt">species</span> increased, suggesting that the dominance of dominant <span class="hlt">species</span> was continuously improved with succession. In the succession process of broad-leaved Korean pine forest in Changbai Mountains, Betula platyphylla, Populus davidiana, Phellodendron amurense, Ulmus japonica, and other intolerant or semi-intolerant <span class="hlt">tree</span> <span class="hlt">species</span> decreased, while Tilia amurensis, Fraxinus mandshurica, Pinus koraiensis, Acer mono, and other shade-tolerant <span class="hlt">species</span> increased. PMID:21774305</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1816218H&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1816218H&link_type=ABSTRACT"><span id="translatedtitle">Beech vs. Pine - how different <span class="hlt">tree</span> <span class="hlt">species</span> manage their water demands</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Heidbüchel, Ingo; Dreibrodt, Janek; Simard, Sonia; Güntner, Andreas; Blume, Theresa</p> <p>2016-04-01</p> <p>In north-eastern Germany large parts of the landscape are covered by pine <span class="hlt">trees</span>. Although beech used to be one of the typical <span class="hlt">species</span> for the region, today it makes up only a small fraction of the forested area. In order to reinstate a more natural forest composition an effort is made to decrease the coniferous forest in the next 30 years from 70% to 40% while increasing the deciduous forest from 20% to 40%. This will have consequences for the forest water balance that we would like to understand better. In an attempt to capture the complete <span class="hlt">tree</span> water balance for both <span class="hlt">species</span> we monitored all relevant hydrologic fluxes in four stands of pure beech and pine (both young and old stands) as well as in eight mixed stands (as part of the TERENO observatory). Extensive measurements of throughfall and stemflow were conducted with 35 rain trough systems, 50 stemflow collectors and tipping buckets. Soil moisture was monitored in 70 depth profiles with a total of 450 sensors ranging from 10 cm down to 200 cm. In combination with soil water potential measurements at 5 depths root water uptake from different depths and hydraulic redistribution between depths could be determined. Sapflux sensors recorded <span class="hlt">tree</span> water use for 16 <span class="hlt">trees</span> and groundwater level was monitored at 16 locations. We found that soil moisture conditions under beech were more variable than under pine, especially in the upper 100 cm. This was due to the higher influx of water from stemflow on the one hand and to the more intensive/effective use of soil water by the beech on the other hand. Our sap flux measurements show that beech was able to sustain steady rates of sapflux even under extremely dry soil conditions. While annual average sapflow was twice as high for pines compared to beeches, pine <span class="hlt">trees</span> were less effective in taking up water from the soil and reduced sap flow considerably during dry phases. We still found the upper 100 cm of soil under pine to be generally wetter than under beech and considered</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=325437','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=325437"><span id="translatedtitle">Sensitation potential of tea <span class="hlt">tree</span> essential oils. Impact of the chemical composition on aging and generation of reactive <span class="hlt">species</span>.</span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p>Tea <span class="hlt">tree</span> oil (TTO) is a popular skin remedy obtained from the leaves of Melaleuca alternifolia, M. linariifolia or M dissitiflora. Due to the commercial importance ofTTO, substitution or adulteration with other tea <span class="hlt">tree</span> <span class="hlt">species</span> (such as cajeput, niaouli, manuka and kanuka oils) is common and may p...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2803392','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2803392"><span id="translatedtitle">Neither Host-specific nor Random: Vascular Epiphytes on Three <span class="hlt">Tree</span> <span class="hlt">Species</span> in a Panamanian Lowland Forest</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>LAUBE, STEFAN; ZOTZ, GERHARD</p> <p>2006-01-01</p> <p>• Background and Aims A possible role of host <span class="hlt">tree</span> identity in the structuring of vascular epiphyte communities has attracted scientific attention for decades. Specifically, it has been suggested that each host <span class="hlt">tree</span> <span class="hlt">species</span> has a specific subset of the local <span class="hlt">species</span> pool according to its own set of properties, e.g. physicochemical characteristics of the bark, <span class="hlt">tree</span> architecture, or leaf phenology patterns. • Methods A novel, quantitative approach to this question is presented, taking advantage of a complete census of the vascular epiphyte community in 0·4 ha of undisturbed lowland forest in Panama. For three locally common host-<span class="hlt">tree</span> <span class="hlt">species</span> (Socratea exorrhiza, Marila laxiflora, Perebea xanthochyma) null models were created of the expected epiphyte assemblages assuming that epiphyte colonization reflected random distribution of epiphytes in the forest. • Key Results In all three <span class="hlt">tree</span> <span class="hlt">species</span>, abundances of the majority of epiphyte <span class="hlt">species</span> (69–81 %) were indistinguishable from random, while the remaining <span class="hlt">species</span> were about equally over- or under-represented compared with their occurrence in the entire forest plot. Permutations based on the number of colonized <span class="hlt">trees</span> (reflecting observed spatial patchiness) yielded similar results. Finally, a third analysis (canonical correspondence analysis) also confirmed host-specific differences in epiphyte assemblages. In spite of pronounced preferences of some epiphytes for particular host <span class="hlt">trees</span>, no epiphyte <span class="hlt">species</span> was restricted to a single host. • Conclusions The epiphytes on a given <span class="hlt">tree</span> <span class="hlt">species</span> are not simply a random sample of the local <span class="hlt">species</span> pool, but there are no indications of host specificity either. PMID:16574691</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1813529B&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1813529B&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Tree</span> <span class="hlt">species</span> effects on topsoil properties in an old tropical plantation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bauters, Marijn; Boeckx, Pascal; Ampoorter, Evy; Verbeeck, Hans; Döetterl, Sebastian; Baert, Geert; Verheyen, Kris</p> <p>2016-04-01</p> <p>Forest biogeochemistry is strongly linked to the functional strategies of the <span class="hlt">tree</span> community and the topsoil. Research has long documented that <span class="hlt">tree</span> <span class="hlt">species</span> affect soil properties in forests. Our current understanding on this interaction is mainly based on common garden experiments in temperate forest and needs to be extended to other ecosystems if we want to understand this interaction in natural forests worldwide. Using a 77-year-old tropical experimental plantation from central Africa, we examined the relationship between canopy and litter chemical traits and topsoil properties. By the current diversity in this site, the unique setup allowed us to extend the current knowledge from temperate and simplified systems to near-natural tropical forests, and thus bridge the gap between planted monocultures in common gardens, and correlative studies in natural systems. We linked the <span class="hlt">species</span>-specific leaf and litter chemical traits to the topsoil cation composition, acidity, pH and soil organic matter. We found that average canopy trait values were a better predictor for the topsoil than the litter chemistry. Canopy base cation content positively affected topsoil pH and negatively affected acidity. These, in turn strongly determined the soil organic carbon contents of the topsoil, which ranged a <span class="hlt">tree</span>-fold in the experiment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/12683726','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/12683726"><span id="translatedtitle">137Cs distribution among annual rings of different <span class="hlt">tree</span> <span class="hlt">species</span> contaminated after the Chernobyl accident.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Soukhova, N V; Fesenko, S V; Klein, D; Spiridonov, S I; Sanzharova, N I; Badot, P M</p> <p>2003-01-01</p> <p>The distributions of 137Cs among annual rings of Pinus sylvestris and Betula pendula at four experimental sites located in the most contaminated areas in the Russian territory after the Chernobyl accident in 1986 were studied. <span class="hlt">Trees</span> of different ages were sampled from four forest sites with different <span class="hlt">tree</span> compositions and soil properties. The data analysis shows that 137Cs is very mobile in wood and the 1986 rings do not show the highest contamination. The difference between pine and birch in the pattern of radial 137Cs distribution can be satisfactorily explained by the difference in radial ray composition. 137Cs radial distribution in the wood can be described as the sum of two exponential functions for both <span class="hlt">species</span>. The function parameters are height, age and <span class="hlt">species</span> dependent. The distribution of 137Cs in birch wood reveals much more pronounced dependence on site characteristics and/or the age of <span class="hlt">trees</span> than pines. The data obtained can be used to assess 137Cs content in wood. PMID:12683726</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26854019','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26854019"><span id="translatedtitle">Convergent production and tolerance among 107 woody <span class="hlt">species</span> and divergent production between shrubs and <span class="hlt">trees</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>He, Wei-Ming; Sun, Zhen-Kai</p> <p>2016-01-01</p> <p>Green leaves face two fundamental challenges (i.e., carbon fixation and stress tolerance) during their lifespan. However, the relationships between leaf production potential and leaf tolerance potential have not been explicitly tested with a broad range of plant <span class="hlt">species</span> in the same environment. To do so, we conducted a field investigation based on 107 woody plants grown in a common garden and complementary laboratory measurements. The values, as measured by a chlorophyll meter, were significantly related to the direct measurements of chlorophyll content on a leaf area basis. Area-based chlorophyll content was positively correlated with root surface area, whole-plant biomass, leaf mass per area (LMA), and force to punch. Additionally, LMA had a positive correlation with force to punch. Shrubs had a higher leaf chlorophyll content than <span class="hlt">trees</span>; however, shrubs and <span class="hlt">trees</span> exhibited a similar leaf lifespan, force to punch, and LMA. These findings suggest that the production potential of leaves and their tolerance to stresses may be convergent in woody <span class="hlt">species</span> and that the leaf production potential may differ between shrubs and <span class="hlt">trees</span>. This study highlights the possibility that functional convergence and divergence might be linked to long-term selection pressures and genetic constraints. PMID:26854019</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/15334971','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/15334971"><span id="translatedtitle">[Characters of greening <span class="hlt">tree</span> <span class="hlt">species</span> in heavy metal pollution protection in Shanghai].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yang, Xuejun; Tang, Dongqin; Xu, Dongxin; Wang, Xinhua; Pan, Gaohong</p> <p>2004-04-01</p> <p>In this paper, the stream banks nearby Qibao town and the factory area of Shanghai Baoshan Steel Company were selected as the typical areas contaminated by heavy metals. The polluted status was investigated by measuring the heavy metal concentrations of the sampled soils. The results showed that the heavy metal concentrations in the soils of stream banks were a little higher than the control, but obviously higher in the factory area of Shanghai Baoshan Steel Company. The growth status of the greening <span class="hlt">trees</span> was recorded, and their heavy metal concentrations were measured by ICP. According to the research results and historic data, the excellent greening <span class="hlt">tree</span> <span class="hlt">species</span> mainly applied in polluted factory area were Viburnum awabuki, Lagerstroemia indica, Hibiscus mutabilis, Ligustrum lucidum and Sabina chinensis, which could grow well on contaminated soil, and accumulate high concentrations of heavy metal elements. The other <span class="hlt">tree</span> <span class="hlt">species</span> such as Distylium racemosum, Nerium indicum, and Photinia serrulata might be also available in greening for heavy metal pollution protection. PMID:15334971</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4356318','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4356318"><span id="translatedtitle">A genotyping protocol for multiple tissue types from the polyploid <span class="hlt">tree</span> <span class="hlt">species</span> Sequoia sempervirens (Cupressaceae)1</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Narayan, Lakshmi; Dodd, Richard S.; O’Hara, Kevin L.</p> <p>2015-01-01</p> <p>Premise of the study: Identifying clonal lineages in asexually reproducing plants using microsatellite markers is complicated by the possibility of nonidentical genotypes from the same clonal lineage due to somatic mutations, null alleles, and scoring errors. We developed and tested a clonal identification protocol that is robust to these issues for the asexually reproducing hexaploid <span class="hlt">tree</span> <span class="hlt">species</span> coast redwood (Sequoia sempervirens). Methods: Microsatellite data from four previously published and two newly developed primers were scored using a modified protocol, and clones were identified using Bruvo genetic distances. The effectiveness of this clonal identification protocol was assessed using simulations and by genotyping a test set of paired samples of different tissue types from the same <span class="hlt">trees</span>. Results: Data from simulations showed that our protocol allowed us to accurately identify clonal lineages. Multiple test samples from the same <span class="hlt">trees</span> were identified correctly, although certain tissue type pairs had larger genetic distances on average. Discussion: The methods described in this paper will allow for the accurate identification of coast redwood clones, facilitating future studies of the reproductive ecology of this <span class="hlt">species</span>. The techniques used in this paper can be applied to studies of other clonal organisms as well. PMID:25798341</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4745073','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4745073"><span id="translatedtitle">Convergent production and tolerance among 107 woody <span class="hlt">species</span> and divergent production between shrubs and <span class="hlt">trees</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>He, Wei-Ming; Sun, Zhen-Kai</p> <p>2016-01-01</p> <p>Green leaves face two fundamental challenges (i.e., carbon fixation and stress tolerance) during their lifespan. However, the relationships between leaf production potential and leaf tolerance potential have not been explicitly tested with a broad range of plant <span class="hlt">species</span> in the same environment. To do so, we conducted a field investigation based on 107 woody plants grown in a common garden and complementary laboratory measurements. The values, as measured by a chlorophyll meter, were significantly related to the direct measurements of chlorophyll content on a leaf area basis. Area-based chlorophyll content was positively correlated with root surface area, whole-plant biomass, leaf mass per area (LMA), and force to punch. Additionally, LMA had a positive correlation with force to punch. Shrubs had a higher leaf chlorophyll content than <span class="hlt">trees</span>; however, shrubs and <span class="hlt">trees</span> exhibited a similar leaf lifespan, force to punch, and LMA. These findings suggest that the production potential of leaves and their tolerance to stresses may be convergent in woody <span class="hlt">species</span> and that the leaf production potential may differ between shrubs and <span class="hlt">trees</span>. This study highlights the possibility that functional convergence and divergence might be linked to long-term selection pressures and genetic constraints. PMID:26854019</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2000AcO....21...37K&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2000AcO....21...37K&link_type=ABSTRACT"><span id="translatedtitle">Some autecological characteristics of early to late successional <span class="hlt">tree</span> <span class="hlt">species</span> in Venezuela</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kammesheidt, Ludwig</p> <p>2000-01-01</p> <p>The breadth of the continuum concept of strategy with respect to succession was tested on 21 <span class="hlt">tree</span> and shrub <span class="hlt">species</span> common in either unlogged or logged stands, respectively, in the Forest Reserve of Caparo, Venezuela, by examining morphological, physiological and population characteristics. Based on a preliminary abundance analysis, `early', `mid' and `late' successional <span class="hlt">species</span> as well as `generalists' were distinguished. Early successional <span class="hlt">species</span>, i.e. Ochroma lagopus, Heliocarpus popayanensis and Cecropia peltata were similar in many autecological aspects, e.g. monolayered leaf arrangement, orthotropic architectural models, no adaptive reiteration, clumped distribution, but differed in gap association and distribution along a drainage gradient. Mid-successional <span class="hlt">species</span> established themselves both in large and small gaps (> 300 m[sup2 ]; 80-300 m[sup2 ]) and showed a clumped to regular distribution pattern in logged areas; they exhibited more diverse crown and leaf characteristics than early successional <span class="hlt">species</span>. Late successional <span class="hlt">species</span> established themselves only in small gaps and understorey, and showed a regular spatial pattern in undisturbed areas. All late successional <span class="hlt">species</span> displayed architectural models with plagiotropic lateral axes and showed a multilayered leaf arrangement. Adaptive reiteration was a common feature of late successional <span class="hlt">species</span> which could be further subdivided into large, medium-sized and small <span class="hlt">trees</span>, indicating different light requirements at maturity. Generalists were common treelet and shrub <span class="hlt">species</span> in both disturbed and undisturbed sites where they are also capable of completing their life cycle. The light compensation point (LCP) of an individual plant was strongly influenced by its crown illuminance. Large late successional <span class="hlt">species</span> showed the widest range of LCP values, reflecting the increasing light availability with increasing height in mature forest. On the basis of many autecological characteristics, it was found (i</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/20030130','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/20030130"><span id="translatedtitle">[Time lag characteristics of stem sap flow of common <span class="hlt">tree</span> <span class="hlt">species</span> during their growth season in Beijing downtown].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Hua; Ouyang, Zhi-yun; Zheng, Hua; Wang, Xiao-ke; Ni, Yong-ming; Ren, Yu-fen</p> <p>2009-09-01</p> <p>From April to September in 2008, the stem sap flow velocity (Js) of several common <span class="hlt">tree</span> <span class="hlt">species</span> (Ginkgo biloba, Aesculus chinensis, Magnolia denudata, Robinia pseudoacacia, Pinus tabulaeformis and Cedrus deodara) in Beijing was measured by thermal dissipation method. Crosscorrelation analysis was used to estimate the time lag between the stem sap flow and the driving factors of canopy transpiration among the <span class="hlt">tree</span> <span class="hlt">species</span>. The Js of the six <span class="hlt">tree</span> <span class="hlt">species</span> was significantly correlated with the total radiation (Rs) and vapor pressure deficit (D), and the Js was lagged behind Rs but ahead of D. The maximum correlation coefficient of Js with Rs (0.74-0.93) was often higher than that of Js with D (0.57-0.79), indicating that the diurnal Js was more dependent on Rs than on D. The sampled <span class="hlt">tree</span> <span class="hlt">species</span> except P. tabulaeformis had a shorter time lag of Js with Rs (10-70 min) than with D (47-130 min), and there existed significant differences among R. pseudoacacia, P. tabulaeformis, and C. deodara. The time lag between the Js and the driving factors of canopy transpiration was mainly correlated with the <span class="hlt">tree</span> features (DBH, <span class="hlt">tree</span> height, canopy area, and sapwood area) and the nocturnal water recharge, regardless of <span class="hlt">tree</span> <span class="hlt">species</span>. PMID:20030130</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18055429','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18055429"><span id="translatedtitle">Retranslocation of foliar nutrients in evergreen <span class="hlt">tree</span> <span class="hlt">species</span> planted in a Mediterranean environment.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fife, D N; Nambiar, E K S; Saur, E</p> <p>2008-02-01</p> <p>Internal nutrient recycling through retranslocation (resorption) is important for meeting the nutrient demands of new tissue production in <span class="hlt">trees</span>. We conducted a comparative study of nutrient retranslocation from leaves of five <span class="hlt">tree</span> <span class="hlt">species</span> from three genera grown in plantation forests for commercial or environmental purposes in southern Australia--Acacia mearnsii De Wild., Eucalyptus globulus Labill., E. fraxinoides H. Deane & Maiden, E. grandis W. Hill ex Maiden and Pinus radiata D. Don. Significant amounts of nitrogen, phosphorus and potassium were retranslocated during three phases of leaf life. In the first phase, retranslocation occurred from young leaves beginning 6 months after leaf initiation, even when leaves were physiologically most active. In the second phase, retranslocation occurred from mature green leaves during their second year, and in the third phase, retranslocation occurred during senescence before leaf fall. Nutrient retranslocation occurred mainly in response to new shoot production. The pattern of retranslocation was remarkably similar in the leaves of all study <span class="hlt">species</span> (and in the phyllodes of Casuarina glauca Sieber ex Spreng.), despite their diverse genetics, leaf forms and growth rates. There was no net retranslocation of calcium in any of the <span class="hlt">species</span>. The amounts of nutrients at the start of each pre-retranslocation phase had a strong positive relationship with the amounts subsequently retranslocated, and all <span class="hlt">species</span> fitted a common relationship. The percentage reduction in concentration or content (retranslocation efficiency) at a particular growth phase is subject to many variables, even within a <span class="hlt">species</span>, and is therefore not a meaningful measure of interspecific variation. It