Environmental Filtering Influences Functional Community Assembly of 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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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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Trait-based community assembly of epiphytic diatoms in saline astatic ponds: a test of the stress-dominance hypothesis

Scientific Reports ◽

10.1038/s41598-019-52304-4 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 3

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.

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Functional volumes, niche packing and species richness: biogeographic legacies in the Congo Basin

Royal Society Open Science ◽

10.1098/rsos.191582 ◽

2020 ◽

Vol 7 (3) ◽

pp. 191582 ◽

Cited By ~ 2

Author(s):

Frederik Van de Perre ◽

Michael R. Willig ◽

Steven J. Presley ◽

Itoka Jean-Claude Mukinzi ◽

Mbalitini Sylvestre Gambalemoke ◽

...

Keyword(s):

Species Richness ◽

Community Assembly ◽

Species Coexistence ◽

Environmental Filtering ◽

Biotic Interactions ◽

Congo Basin ◽

Climatic Fluctuations ◽

Fundamental Goal ◽

Vicariance Event ◽

Lowland Forests

Understanding the determinants of species coexistence in complex and species-rich communities is a fundamental goal of ecology. Patterns of species coexistence depend on how biotic interactions and environmental filtering act over ecological and evolutionary time scales. Climatic fluctuations in lowland rainforests of the Congo Basin led to the number of vertebrate species being significantly lower in central compared with northern ecoregions of the Basin. We used null models to assess whether climatic variations affected the community assembly of shrews. A consistent limit to functional similarity of species was not related to species richness. Rather, species richness is constrained by environmental factors, and these constraints are stronger in the central lowland forests of the Congo Basin. By constraining species geographic distributions, historical effects of rainforest refugia arising from climatic fluctuations may affect contemporary species composition of local shrew communities. The Congo River represents a vicariance event that led to allopatric speciation of shrews and continues to represent a barrier to dispersal. Ultimately, the historical effects of this barrier have led to differences in the functional volume of shrew communities in northern and central ecoregions. We suggest that the analyses of community assembly can be used to identify Holocene refugia in the Congo Basin.

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Phylogenetic and functional trait-based community assembly within Pacific Cyrtandra (Gesneriaceae): evidence for clustering at multiple spatial scales

10.21203/rs.3.rs-1017906/v1 ◽

2021 ◽

Author(s):

Melissa Johnson

Keyword(s):

Community Assembly ◽

Phylogenetic Signal ◽

Spatial Scales ◽

Environmental Filtering ◽

Alpha Diversity ◽

Leaf Traits ◽

Functional Trait ◽

The Pacific ◽

Island Communities ◽

Coexisting Species

Abstract Tropical rainforest communities are often characterized by a small number of species-rich genera that contribute disproportionately to the alpha diversity in these habitats. In the Pacific Basin there are nearly 200 species of Cyrtandra, most of which are white-flowered woody shrubs that are single-island endemics. Within these island communities, multiple Cyrtandra species are commonly observed to occur sympatrically in wet forest understories, forming swarms of what appear to be ecologically similar taxa. The aim of this study was to determine if communities of these plants are randomly assembled with respect to phylogenetic relatedness and traits that are ecologically relevant. Using a combination of ten functional traits and a well-resolved species phylogeny, I examined community assembly within 34 species of Cyrtandra across three Pacific archipelagoes. Coexisting species were generally found to be more closely related and more phenotypically similar than would be expected by chance. This pattern was observed at both broad (island communities) and fine (site communities) spatial scales. The retention of phylogenetic signal in floral traits and the strong influence of these traits on the observed degree of phylogenetic clustering may indicate that pollinators act as a biotic filter for closely related species of Cyrtandra. In contrast, the absence of phylogenetic signal in most leaf traits, coupled with the lower contribution of these traits to niche clustering, suggests that environmental filtering along this trait axis is minimal in the observed communities. This study supports the theory that plant communities are not randomly assembled, and instead, that niche-based processes structure biodiversity at broad and fine spatial scales in diverse congeneric species assemblages.

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Rare Microbial Taxa Emerge When Communities Collide: Freshwater and Marine Microbiome Responses to Experimental Seawater Intrusion

10.1101/550756 ◽

2019 ◽

Author(s):

Jennifer D. Rocca ◽

Marie Simonin ◽

Justin P. Wright ◽

Alex Washburne ◽

Emily Bernhardt

Keyword(s):

Community Assembly ◽

Environmental Filtering ◽

Biotic Interactions ◽

Structure And Function ◽

Reciprocal Transplant ◽

Critical Component ◽

Central Question ◽

Marine Communities ◽

Rare Biosphere ◽

And Function

AbstractWhole microbial communities regularly merge with one another, often in tandem with their environments, in a process called community coalescence. Such events allow us to address a central question in ecology – what processes shape community assembly. We used a reciprocal transplant and mixing experiment to directly and independently unravel the effects of environmental filtering and biotic interactions on microbiome success when freshwater and marine communities coalesce. The brackish treatment and community mixing resulted in strong convergence of microbiome structure and function toward the marine. Brackish exposure imposed a 96% taxa loss from freshwater and 66% loss from marine microbiomes, which was somewhat counterbalanced by the emergence of tolerant rare taxa. Community mixing further resulted in 29% and 49% loss from biotic interactions between freshwater and marine microbiomes, offset somewhat by mutualistically-assisted rare microbial taxa. Our study emphasizes the importance of the rare biosphere as a critical component of community resilience.

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Ecophylogeny of the endospheric root fungal microbiome of co-occurring Agrostis stolonifera

PeerJ ◽

10.7717/peerj.3454 ◽

2017 ◽

Vol 5 ◽

pp. e3454 ◽

Cited By ~ 19

Author(s):

Amandine Lê Van ◽

Achim Quaiser ◽

Marie Duhamel ◽

Sophie Michon-Coudouel ◽

Alexis Dufresne ◽

...

Keyword(s):

Community Assembly ◽

Environmental Filtering ◽

Functional Trait ◽

Agrostis Stolonifera ◽

Fungal Communities ◽

Plant Host ◽

Expression Ratio ◽

Dna And Rna ◽

Host Effect ◽

Fungal Microbiome

Background Within the root endosphere, fungi are known to be important for plant nutrition and resistance to stresses. However, description and understanding of the rules governing community assembly in the fungal fraction of the plant microbiome remains scarce. Methods We used an innovative DNA- and RNA-based analysis of co-extracted nucleic acids to reveal the complexity of the fungal community colonizing the roots of an Agrostis stolonifera population. The normalized RNA/DNA ratio, designated the ‘mean expression ratio’, was used as a functional trait proxy. The link between this trait and phylogenetic relatedness was measured using the Blomberg’s K statistic. Results Fungal communities were highly diverse. Only ∼1.5% of the 635 OTUs detected were shared by all individuals, however these accounted for 33% of the sequence number. The endophytic fungal communities in plant roots exhibit phylogenetic clustering that can be explained by a plant host effect acting as environmental filter. The ‘mean expression ratio’ displayed significant but divergent phylogenetic signals between fungal phyla. Discussion These results suggest that environmental filtering by the host plant favours the co-existence of related and similar OTUs within the Basidiomycota community assembly, whereas the Ascomycota and Glomeromycota communities seem to be impacted by competitive interactions which promote the co-existence of phylogenetically related but ecologically dissimilar OTUs.

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

10.1101/768283 ◽

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.

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Understanding Community Assembly Based on Functional Traits, Ontogenetic Stages, Habitat Types and Spatial Scales in a Subtropical Forest

Forests ◽

10.3390/f10121055 ◽

2019 ◽

Vol 10 (12) ◽

pp. 1055 ◽

Cited By ~ 1

Author(s):

Yanpeng Li ◽

Yue Bin ◽

Han Xu ◽

Yunlong Ni ◽

Ruyun Zhang ◽

...

Keyword(s):

Leaf Area ◽

Functional Traits ◽

Community Assembly ◽

Spatial Scales ◽

Environmental Filtering ◽

Biotic Interactions ◽

Habitat Types ◽

Ontogenetic Stages ◽

Dispersion Patterns ◽

Natural Communities

Community assembly in natural communities is commonly explained by stochastic and niche-based processes such as environmental filtering and biotic interactions. Many studies have inferred the importance of these processes using a trait-based approach, however, there are still unknowns around what factors affect the importance of different assembly processes in natural communities. In this study, the trait dispersion patterns of 134 species were examined across different functional traits, habitat types, ontogenetic stages and spatial scales from a 20-ha Dinghushan Forest Dynamic Plot in China. The results showed that (1) functional traits related to productivity such as specific leaf area and leaf area mainly showed functional clustering, indicating these two functional traits were more affected by environmental filtering. However, trait dispersion patterns depended on more than the ecological significances of functional traits. For example, trait dispersions of leaf dry matter content, leaf thickness and maximum height did not show consistent patterns across habitat types and ontogenetic stages, suggesting more complex mechanisms may operate on these traits; (2) the trait dispersion varied with the habitat types and ontogenetic stages. Specifically, we found that habitat types only affected the strength of trait dispersions for all the five traits, but ontogenetic stages influenced both the strength and direction of trait dispersions, which depended on the traits selected; (3) the relative importance of soil, topography and space to trait dispersion varied with ontogenetic stages. Topography and space were more important for trait dispersion of saplings but soil was more important for trait dispersion of adults; (4) biotic interactions dominated community assembly at smaller spatial scales but environmental filtering dominated community assembly at larger spatial scales. Overall, the results highlight the importance of functional traits, habitat types, ontogenetic stages and spatial scales to community assembly in natural communities.

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

Scientific Reports ◽

10.1038/s41598-020-76645-7 ◽

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.

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Solutions in microbiome engineering: prioritizing barriers to organism establishment

The ISME Journal ◽

10.1038/s41396-021-01088-5 ◽

2021 ◽

Author(s):

Michaeline B. N. Albright ◽

Stilianos Louca ◽

Daniel E. Winkler ◽

Kelli L. Feeser ◽

Sarah-Jane Haig ◽

...

Keyword(s):

Microbial Community ◽

Ecosystem Function ◽

Restoration Ecology ◽

Propagule Pressure ◽

Environmental Filtering ◽

Biotic Interactions ◽

Invasion Biology ◽

Engineering Research

AbstractMicrobiome engineering is increasingly being employed as a solution to challenges in health, agriculture, and climate. Often manipulation involves inoculation of new microbes designed to improve function into a preexisting microbial community. Despite, increased efforts in microbiome engineering inoculants frequently fail to establish and/or confer long-lasting modifications on ecosystem function. We posit that one underlying cause of these shortfalls is the failure to consider barriers to organism establishment. This is a key challenge and focus of macroecology research, specifically invasion biology and restoration ecology. We adopt a framework from invasion biology that summarizes establishment barriers in three categories: (1) propagule pressure, (2) environmental filtering, and (3) biotic interactions factors. We suggest that biotic interactions is the most neglected factor in microbiome engineering research, and we recommend a number of actions to accelerate engineering solutions.

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