Community assembly along a soil depth gradient: contrasting patterns of plant trait convergence and divergence in a Mediterranean rangeland

Multiple ecological processes simultaneously govern community assembly, but it remains unclear how abiotic stressors regulate the relative importance of these processes among different biogeographic regions. Therefore, we conducted a comprehensive study on the responses of community assembly to varying environmental gradients, using the mean, variance, skewness, and kurtosis of plant height (height), specific leaf area (SLA) and leaf dry matter content (LDMC) distributions on the Tibetan Plateau (TP) and the Mongolian Plateau (MP). Our results showed that the prevalence of trait convergence across all grasslands in both TP and MP seem to be the result of abiotic filtering or weaker competitive exclusion etc. These trait-convergence assembly processes decrease the functional dispersion but increase the evenness of the trait frequency distribution. The mean, variance, skewness, and kurtosis responses of grassland communities to abiotic stress varied between the TP and MP. On average, plant trait distribution was mainly driven by temperature on the TP, and low-temperature stress altered the community assembly rules. In contrast, water availability shaped plant trait frequency distributions on the MP, and drought stress mediated the balance between different assembly processes. Our results provide empirical evidence that divergent abiotic stressors regulate the grassland community assembly on the TP and MP. Together, our study speculates that different aspects of future climate change, such as climate warming and changing precipitation patterns, on community assembly are dependent on regional climatic regimes.

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

10.1101/528836 ◽

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.

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Re‐growing a tropical dry forest: functional plant trait composition and community assembly during succession

Functional Ecology ◽

10.1111/1365-2435.12579 ◽

2015 ◽

Vol 30 (6) ◽

pp. 1006-1013 ◽

Cited By ~ 38

Author(s):

Vanessa Buzzard ◽

Catherine M. Hulshof ◽

Trevor Birt ◽

Cyrille Violle ◽

Brian J. Enquist

Keyword(s):

Community Assembly ◽

Tropical Dry Forest ◽

Dry Forest ◽

Plant Trait

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Which randomizations detect convergence and divergence in trait-based community assembly? A test of commonly used null models

Journal of Vegetation Science ◽

10.1111/jvs.12452 ◽

2016 ◽

Vol 27 (6) ◽

pp. 1275-1287 ◽

Cited By ~ 34

Author(s):

Lars Götzenberger ◽

Zoltán Botta-Dukát ◽

Jan Lepš ◽

Meelis Pärtel ◽

Martin Zobel ◽

...

Keyword(s):

Community Assembly ◽

Null Models ◽

Convergence And Divergence

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Partitioning of functional diversity reveals the scale and extent of trait convergence and divergence

Journal of Vegetation Science ◽

10.1111/j.1654-1103.2009.01042.x ◽

2009 ◽

Vol 20 (3) ◽

pp. 475-486 ◽

Cited By ~ 170

Author(s):

Francesco de Bello ◽

Wilfried Thuiller ◽

Jan Lepš ◽

Philippe Choler ◽

Jean-Christophe Clément ◽

...

Keyword(s):

Functional Diversity ◽

Trait Convergence ◽

Convergence And Divergence

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Environmental Filtering Influences Functional Community Assembly of Epibenthic Communities

Frontiers in Marine Science ◽

10.3389/fmars.2021.736917 ◽

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.

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