scholarly journals Distinguishing the signatures of local environmental filtering and regional trait range limits in the study of trait-environment relationships

2019 ◽  
Author(s):  
Pierre Denelle ◽  
Cyrille Violle ◽  
François Munoz
Keyword(s):  
Community Assembly ◽  
Environmental Gradients ◽  
Boundary Effect ◽  
Extreme Environments ◽  
Environmental Filtering ◽  
Range Limits ◽  
Species Pool ◽  
Statistical Tool ◽  
Leaf Trait ◽  
Trait Convergence

AbstractUnderstanding the imprint of environmental filtering on community assembly along environmental gradients is a key objective of trait-gradient analyses. Depending on local constraints, this filtering generally entails that species departing from an optimum trait value have lower abundances in the community. The Community-Weighted Mean (CWM) and Variance (CWV) of trait values are then expected to depict the optimum and intensity of filtering, respectively. However, the trait distribution within the regional species pool and its limits can also affect local CWM and CWV values apart from the effect of environmental filtering. The regional trait range limits are more likely to be reached in communities at the extremes of environmental gradients. Analogous to the mid-domain effect in biogeography, decreasing CWV values in extreme environments can then represent the influence of regional trait range limits rather than stronger filtering in the local environment. We name this effect the “Trait-Gradient Boundary Effect” (TGBE). First, we use a community assembly framework to build simulated communities along a gradient from a species pool and environmental filtering with either constant or varying intensity while accounting for immigration processes. We demonstrate the significant influence of TGBE, in parallel to environmental filtering, on CWM and CWV at the extremes of the environmental gradient. We provide a statistical tool based on Approximate Bayesian Computation to decipher the respective influence of local environmental filtering and regional trait range limits. Second, as a case study, we reanalyze the functional composition of alpine plant communities distributed along a gradient of snow cover duration. We show that leaf trait convergence found in communities at the extremes of the gradient reflect an influence of trait range limits rather than stronger environmental filtering. These findings challenge correlative trait-environment relationships and call for more explicitly identifying the mechanisms responsible of trait convergence/divergence along environmental gradients.

scholarly journals Trait-based community assembly of epiphytic diatoms in saline astatic ponds: a test of the stress-dominance hypothesis

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Éva Ács ◽  
Angéla Földi ◽  
Csaba Ferenc Vad ◽  
Zsuzsa Trábert ◽  
Keve Tihamér Kiss ◽  
...  
Keyword(s):  
Functional Diversity ◽  
Community Assembly ◽  
Environmental Gradients ◽  
N Uptake ◽  
Environmental Filtering ◽  
Limiting Similarity ◽  
Epiphytic Diatoms ◽  
Assembly Rule ◽  
Trait Convergence ◽  
Diatom Communities

Abstract The stress dominance hypothesis (SDH) postulates that strong environmental gradients drive trait convergence in communities over limiting similarity. Previous studies, conducted mostly with terrestrial plant communities, found controversial evidence for this prediction. We provide here the first test for SDH for epiphytic diatoms. We studied community assembly in diatom communities of astatic ponds. These water bodies serve as a good model system for testing SDH because they exhibit stress gradients of various environmental factors. Functional diversity of diatom communities was assessed based on four traits: (1) combined trait reflecting the trade-off between stress tolerance and competitive dominance, (2) cell size, (3) oxygen requirement and (4) N-uptake strategy. According to our results, salinity, pH and the width of the macrophyte belt appeared as significant predictors of the trait convergence/divergence patterns presumably acting through influencing the availability of carbon dioxide and turbidity. Lower trait diversity was found in turbid, more saline and more alkaline ponds and functional diversity was higher in transparent, less saline and less alkaline ponds. Overall, our results supported the stress dominance hypothesis. In habitats representing increased environmental stress, environmental filtering was the most important community assembly rule, while limiting similarity became dominant under more favourable conditions.

scholarly journals Trait convergence and trait divergence in lake phytoplankton reflect community assembly rules

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Gábor Borics ◽  
Viktória B-Béres ◽  
István Bácsi ◽  
Balázs A. Lukács ◽  
E. T-Krasznai ◽  
...  
Keyword(s):  
Environmental Stress ◽  
Community Assembly ◽  
Environmental Gradients ◽  
Environmental Filtering ◽  
Limiting Similarity ◽  
Relative Importance ◽  
Trait Divergence ◽  
Phytoplankton Communities ◽  
Trait Convergence ◽  
Phytoplankton Traits

Abstract Environmental filtering and limiting similarity are those locally acting processes that influence community structure. These mechanisms acting on the traits of species result in trait convergence or divergence within the communities. The role of these processes might change along environmental gradients, and it has been conceptualised in the stress-dominance hypothesis, which predicts that the relative importance of environmental filtering increases and competition decreases with increasing environmental stress. Analysing trait convergence and divergence in lake phytoplankton assemblages, we studied how the concepts of ‘limiting similarity’ versus ‘environmental filtering’ can be applied to these microscopic aquatic communities, and how they support or contradict the stress-dominance hypothesis. Using a null model approach, we investigated the divergence and convergence of phytoplankton traits along environmental gradients represented by canonical axes of an RDA. We used Rao’s quadratic entropy as a measure of functional diversity and calculated effect size (ES) values for each sample. Negative ES values refer to trait convergence, i.e., to the higher probability of the environmental filtering in community assembly, while positive values indicate trait divergence, stressing the importance of limiting similarity (niche partitioning), that is, the competition between the phytoplankters. Our results revealed that limiting similarity and environmental filtering may operate simultaneously in phytoplankton communities, but these assembly mechanisms influenced the distribution of phytoplankton traits differently, and the effects show considerable changes along with the studied scales. Studying the changes of ES values along with the various scales, our results partly supported the stress-dominance hypothesis, which predicts that the relative importance of environmental filtering increases and competition decreases with increasing environmental stress.

scholarly journals Environmental Filtering Influences Functional Community Assembly of Epibenthic Communities

2021 ◽  
Vol 8 ◽  
Author(s):  
Lauren Sutton ◽  
Franz J. Mueter ◽  
Bodil A. Bluhm ◽  
Katrin Iken
Keyword(s):  
Community Assembly ◽  
Chukchi Sea ◽  
Environmental Filtering ◽  
Biotic Interactions ◽  
Beaufort Sea ◽  
Functional Trait ◽  
Functional Community ◽  
Trait Convergence ◽  
High Trait ◽  
Epibenthic Communities

Community assembly theory states that species assemble non-randomly as a result of dispersal limitation, biotic interactions, and environmental filtering. Strong environmental filtering likely leads to local assemblages that are similar in their functional trait composition (high trait convergence) while functional trait composition will be less similar (high trait divergence) under weaker environmental filters. We used two Arctic shelves as case studies to examine the relationship between functional community assembly and environmental filtering using the geographically close but functionally and environmentally dissimilar epibenthic communities on the Chukchi and Beaufort Sea shelves. Environmental drivers were compared to functional trait composition and to trait convergence within each shelf. Functional composition in the Chukchi Sea was more strongly correlated with environmental gradients compared to the Beaufort Sea, as shown by a combination of RLQ and fourth corner analyses and community-weighted mean redundancy analyses. In the Chukchi Sea, epibenthic functional composition, particularly body size, reproductive strategy, and several behavioral traits (i.e., feeding habit, living habit, movement), was most strongly related to gradients in percent mud and temperature while body size and larval development were most strongly related to a depth gradient in the Beaufort Sea. The stronger environmental filter in the Chukchi Sea also supported the hypothesized relationship with higher trait convergence, although this relationship was only evident at one end of the observed environmental gradient. Strong environmental filtering generally provides a challenge for biota and can be a barrier for invading species, a growing concern for the Chukchi Sea shelf communities under warming conditions. Weaker environmental filtering, such as on the Beaufort Sea shelf, generally leads to communities that are more structured by biotic interactions, and possibly representing partitioning of resources among species from intermediate disturbance levels. We provide evidence that environmental filtering can structure functional community composition, providing a baseline of how community function could be affected by stressors such as changes in environmental conditions or increased anthropogenic disturbance.

scholarly journals Leaf trait variation in species-rich tropical Andean forests

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jürgen Homeier ◽  
Tabea Seeler ◽  
Kerstin Pierick ◽  
Christoph Leuschner
Keyword(s):  
Environmental Gradients ◽  
Elevation Gradient ◽  
Environmental Filtering ◽  
Leaf Thickness ◽  
Community Level ◽  
Plant Performance ◽  
Small Scale ◽  
Trait Variation ◽  
Leaf Trait ◽  
Foliar N

AbstractScreening species-rich communities for the variation in functional traits along environmental gradients may help understanding the abiotic drivers of plant performance in a mechanistic way. We investigated tree leaf trait variation along an elevation gradient (1000–3000 m) in highly diverse neotropical montane forests to test the hypothesis that elevational trait change reflects a trend toward more conservative resource use strategies at higher elevations, with interspecific trait variation decreasing and trait integration increasing due to environmental filtering. Analysis of trait variance partitioning across the 52 tree species revealed for most traits a dominant influence of phylogeny, except for SLA, leaf thickness and foliar Ca, where elevation was most influential. The community-level means of SLA, foliar N and Ca, and foliar N/P ratio decreased with elevation, while leaf thickness and toughness increased. The contribution of intraspecific variation was substantial at the community level in most traits, yet smaller than the interspecific component. Both within-species and between-species trait variation did not change systematically with elevation. High phylogenetic diversity, together with small-scale edaphic heterogeneity, cause large interspecific leaf trait variation in these hyper-diverse Andean forests. Trait network analysis revealed increasing leaf trait integration with elevation, suggesting stronger environmental filtering at colder and nutrient-poorer sites.

scholarly journals Hydraulic diversity of El Cien Formation (Baja California Sur, Mexico) and the consequences of functional diversity in paleoclimate estimation using fossil wood

2019 ◽  
Author(s):  
Hugo I. Martínez-Cabrera ◽  
Emilio Estrada-Ruiz
Keyword(s):  
Functional Diversity ◽  
Community Assembly ◽  
Environmental Filtering ◽  
Fossil Wood ◽  
Limiting Similarity ◽  
Environmental Filter ◽  
Climate Gradients ◽  
Wood Trait ◽  
Trait Convergence

ABSTRACTCommunity assembly processes, environmental filtering and limiting similarity, determine functional traits values within communities. Because environment influences the number of viable functional strategies species might take, a strong effect of environmental filter often results in communities having species with similar trait values and narrow functional niches. On the other hand, limiting similarity lead to communities with broader functional spaces. The degree to community assembly processes influence wood trait variation has important implications for paleoclimate estimation using fossil wood since the main tenet of the approach is environmental driven trait convergence, and assumes a central role of environmental filtering. We used functional diversity (FD) to determine how three wood anatomical traits vary in 14 extant communities (272 species) growing under different climate regimes, and inferred the prevalence of environmental filtering/limiting similarity. We also calculated FD metrics for the El Cien Formation fossil woods and discussed the results in light of the current knowledge of the flora. We found lower anatomical diversity in communities growing in dry/cool places (smaller functional spaces and lower abundance of trait combinations), suggesting that strong wood anatomical trait convergence could be the result of stronger habitat filtering in these communities. A lower strength of environmental filter in warm/wet environments, likely results in an amplification of the role of other drivers that promote higher number of hydraulic strategies through niche partition in highly structured communities. More complex ecological structures in mild tropical places likely lead to a higher spread of wood trait values. This asymmetry in the strength of environmental filter along climate gradients, suggest that the imbalances in strength of the trait-climate convergence, should be incorporated in paleoclimate prediction models. FD approach can be used to recognize promising traits with narrow niches along climate gradients, and therefore a constant effect of environmental filter.

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

2012 ◽  
Vol 279 (1746) ◽  
pp. 4447-4456 ◽  
Author(s):  
Bernhard Hoiss ◽  
Jochen Krauss ◽  
Simon G. Potts ◽  
Stuart Roberts ◽  
Ingolf Steffan-Dewenter
Keyword(s):  
Species Richness ◽  
Community Assembly ◽  
Environmental Gradients ◽  
Environmental Filtering ◽  
High Altitudes ◽  
Phylogenetic Structure ◽  
The Alps ◽  
Phylogenetic Composition ◽  
Species Richness And Abundance ◽  
Bee Communities

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

scholarly journals Advances, challenges and a developing synthesis of ecological community assembly theory

2011 ◽  
Vol 366 (1576) ◽  
pp. 2403-2413 ◽  
Author(s):  
Evan Weiher ◽  
Deborah Freund ◽  
Tyler Bunton ◽  
Artur Stefanski ◽  
Tali Lee ◽  
...  
Keyword(s):  
Community Assembly ◽  
Common Ground ◽  
Environmental Gradients ◽  
Environmental Filtering ◽  
Relative Importance ◽  
Species Sorting ◽  
Neutral Processes ◽  
Multiple Processes ◽  
Niche Assembly

Ecological approaches to community assembly have emphasized the interplay between neutral processes, niche-based environmental filtering and niche-based species sorting in an interactive milieu. Recently, progress has been made in terms of aligning our vocabulary with conceptual advances, assessing how trait-based community functional parameters differ from neutral expectation and assessing how traits vary along environmental gradients. Experiments have confirmed the influence of these processes on assembly and have addressed the role of dispersal in shaping local assemblages. Community phylogenetics has forged common ground between ecologists and biogeographers, but it is not a proxy for trait-based approaches. Community assembly theory is in need of a comparative synthesis that addresses how the relative importance of niche and neutral processes varies among taxa, along environmental gradients, and across scales. Towards that goal, we suggest a set of traits that probably confer increasing community neutrality and regionality and review the influences of stress, disturbance and scale on the importance of niche assembly. We advocate increasing the complexity of experiments in order to assess the relative importance of multiple processes. As an example, we provide evidence that dispersal, niche processes and trait interdependencies have about equal influence on trait-based assembly in an experimental grassland.

Inferring community assembly processes from trait diversity across environmental gradients

2016 ◽  
Vol 32 (4) ◽  
pp. 290-299 ◽  
Author(s):  
Yong Shen ◽  
Shi-Xiao Yu ◽  
Ju-Yu Lian ◽  
Hao Shen ◽  
Hong-Lin Cao ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Soil Fertility ◽  
Functional Diversity ◽  
Community Assembly ◽  
Environmental Gradients ◽  
Environmental Filtering ◽  
Competitive Interactions ◽  
Dry Matter Content ◽  
Ecological Processes ◽  
Trait Diversity

Abstract:Environmental filtering and competitive interactions are important ecological processes in community assembly. The contribution of the two processes to community assembly can be evaluated by shifts in functional diversity patterns. We examined the correlations between functional diversity of six traits (leaf chlorophyll concentration, dry matter content, size, specific leaf area, thickness and wood density) and environmental gradients (topography and soil) for 92 species in the 20-ha Dinghushan forest plot in China. A partial Mantel test showed that most of the community-weighted mean trait values changed with terrain convexity and soil fertility, which implied that environmental filtering was occurring. Functional diversity of many traits significantly increased with increasing terrain convexity and soil fertility, which was associated with increased light and below-ground resources respectively. These results suggest that co-occurring species are functionally convergent in regions of strong abiotic stress under the environmental filtering, but functionally divergent in more benign environments due to resource partitioning and competitive interactions. Single-trait diversity and multivariate functional diversity had different relationships with environmental factors, indicating that traits were related to different niche axes, and associated with different ecological processes, which demonstrated the importance of focusing niche axes in traits selection. Between 9% and 41% of variation in functional diversity of different traits was explained by environmental factors in stepwise multiple regression models. Terrain convexity and soil fertility were the best predictors of functional diversity, which contributed 30.5% and 29.0% of total R2to the model. These provided essential evidence that different environmental factors had distinguishing impacts on regulating diversity of traits.

Functional species pool framework to test for biotic effects on community assembly

Ecology ◽  
2012 ◽  
Vol 93 (10) ◽  
pp. 2263-2273 ◽  
Author(s):  
Francesco de Bello ◽  
Jodi N. Price ◽  
Tamara Münkemüller ◽  
Jaan Liira ◽  
Martin Zobel ◽  
...  
Keyword(s):  
Community Assembly ◽  
Species Pool ◽  
Biotic Effects

scholarly journals Assembly processes of gastropod community change with horizontal and vertical zonation in ancient Lake Ohrid: a metacommunity speciation perspective

2016 ◽  
Vol 13 (10) ◽  
pp. 2901-2911 ◽  
Author(s):  
Torsten Hauffe ◽  
Christian Albrecht ◽  
Thomas Wilke
Keyword(s):  
Community Composition ◽  
Community Assembly ◽  
Environmental Filtering ◽  
Dispersal Limitation ◽  
Species Interaction ◽  
Relative Importance ◽  
Lake Depth ◽  
Ancient Lake ◽  
Lake Ohrid ◽  
Speciation Model

Abstract. The Balkan Lake Ohrid is the oldest and most diverse freshwater lacustrine system in Europe. However, it remains unclear whether species community composition, as well as the diversification of its endemic taxa, is mainly driven by dispersal limitation, environmental filtering, or species interaction. This calls for a holistic perspective involving both evolutionary processes and ecological dynamics, as provided by the unifying framework of the “metacommunity speciation model”.The current study used the species-rich model taxon Gastropoda to assess how extant communities in Lake Ohrid are structured by performing process-based metacommunity analyses. Specifically, the study aimed (1) to identifying the relative importance of the three community assembly processes and (2) to test whether the importance of these individual processes changes gradually with lake depth or discontinuously with eco-zone shifts.Based on automated eco-zone detection and process-specific simulation steps, we demonstrated that dispersal limitation had the strongest influence on gastropod community composition. However, it was not the exclusive assembly process, but acted together with the other two processes – environmental filtering and species interaction. The relative importance of the community assembly processes varied both with lake depth and eco-zones, though the processes were better predicted by the latter.This suggests that environmental characteristics have a pronounced effect on shaping gastropod communities via assembly processes. Moreover, the study corroborated the high importance of dispersal limitation for both maintaining species richness in Lake Ohrid (through its impact on community composition) and generating endemic biodiversity (via its influence on diversification processes). However, according to the metacommunity speciation model, the inferred importance of environmental filtering and biotic interaction also suggests a small but significant influence of ecological speciation. These findings contribute to the main goal of the Scientific Collaboration on Past Speciation Conditions in Lake Ohrid (SCOPSCO) deep drilling initiative – inferring the drivers of biotic evolution – and might provide an integrative perspective on biological and limnological dynamics in ancient Lake Ohrid.

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