Asymmetrical pegs in square holes? Functional and phylogenetic determinants of plant community assembly in temperate forest understories

ABSTRACTDespite advances in community assembly theory, uncertainties remain regarding how ecological and evolutionary processes shape species distributions and communities. We analyzed patterns of occurrence for 139 herbaceous plant species across 257 forest stands in Wisconsin (USA) to test predictions from community assembly theory. Specifically, we applied Bayesian phylogenetic linear mixed effects models (PGLMMs) to examine how functional traits and phylogenetic relationships influence plant distributions along environmental gradients and how functional similarity and phylogenetic relatedness affect local species co-occurrence. Leaf height, specific leaf area, and seed mass mediate species distributions along edaphic, climatic, and light gradients. In contrast, functional trait similarity and phylogenetic relationships only weakly affect patterns of local co-occurrence. These results confirm that broad-scale plant distributions are largely shaped by ecological sorting along environmental gradients but suggest deterministic assembly rules based on niche differentiation and complementary resource use may not govern local species co-occurrence in homogeneous environments.Statement of authorshipJB conceived the idea for the study. DL, SJ, and DR collected the vegetation and functional trait data. JB analyzed the data with assistance from DL. KC, KS, TG, and DW secured funding for research and oversaw data collection. JB wrote the first draft of the manuscript, all authors contributed to manuscript revisions.Data accessibility statementUpon acceptance, data will be archived at Figshare (https://figshare.com/) and scripts used to analyze the data will be shared on Github (https://github.com/jaredjbeck/).

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Functional niche occupation and species richness in herbaceous plant communities along experimental gradients of stress and disturbance

Annals of Botany ◽

10.1093/aob/mcz140 ◽

2019 ◽

Vol 124 (5) ◽

pp. 861-867

Author(s):

Yuanzhi Li ◽

Bill Shipley

Keyword(s):

Species Richness ◽

Environmental Gradients ◽

Experimental System ◽

Niche Overlap ◽

Functional Trait ◽

Limiting Similarity ◽

Herbaceous Plant ◽

Habitat Filtering ◽

Intraspecific Trait Variation ◽

Different Levels

Abstract Background and Aims The patterns of niche occupation in functional trait space have been widely studied to understand the processes of community assembly, but are rarely linked to environmental conditions (here, stress and disturbance). In this study, we investigate (1) how the pattern of functional niche occupation, incorporating intraspecific trait variation and covariation, varies along experimental gradients of stress and disturbance, (2) whether habitat filtering and/or limiting similarity modify the pattern, and (3) whether their strength varies as a function of species richness or levels of stress and disturbance. Methods We constructed an experimental system consisting of 24 herbaceous plant mesocosms under different levels of stress and disturbance, and measured ten traits on five individuals for each species in each mesocosm. We quantified the total functional niche volume occupied by an entire mesocosm, the functional niche overlap among species within a mesocosm and the average functional niche volume occupied per species, and investigated how these metrics varied from species-poor to species-rich mesocosms along gradients of stress and disturbance. Key Results Species richness and functional niche overlap correlated positively to disturbance at low and medium levels of stress, but peaked at the intermediate level of disturbance when stress was high. The total functional niche volume and average functional niche volume did not change significantly along these gradients. Compared to null models, each mesocosm occupied a smaller total functional niche volume (habitat filtering) and the species within each mesocosm overlapped less and were more functionally specialized (limiting similarity). Moreover, the standardized metrics (to the null expectations) did not change significantly under different levels of stress and disturbance. Conclusions This experimental evidence shows that both habitat filtering and limiting similarity determine the patterns of functional niche occupation and species richness, but their strength does not change along environmental gradients of stress and disturbance.

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Growth responses to soil water potential indirectly shape local species distributions of tropical forest seedlings

Journal of Ecology ◽

10.1111/1365-2745.13096 ◽

2018 ◽

Cited By ~ 1

Author(s):

Stefan J. Kupers ◽

Bettina M. J. Engelbrecht ◽

Andrés Hernández ◽

S. Joseph Wright ◽

Christian Wirth ◽

...

Keyword(s):

Tropical Forest ◽

Water Potential ◽

Soil Water ◽

Soil Water Potential ◽

Species Distributions ◽

Growth Responses ◽

Local Species

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How to assess species richness along single environmental gradients? Implications of potential versus realized species distributions

Environmental Pollution ◽

10.1016/j.envpol.2015.02.017 ◽

2015 ◽

Vol 200 ◽

pp. 120-125 ◽

Cited By ~ 5

Author(s):

Thomas M.W.J. van Goethem ◽

Mark A.J. Huijbregts ◽

G.W. Wieger Wamelink ◽

Aafke M. Schipper

Keyword(s):

Species Richness ◽

Potential Versus ◽

Environmental Gradients ◽

Species Distributions

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Fire regimes and environmental gradients shape vertebrate and plant distributions in temperate eucalypt forests

Ecosphere ◽

10.1002/ecs2.1781 ◽

2017 ◽

Vol 8 (4) ◽

Cited By ~ 14

Author(s):

Luke T. Kelly ◽

Angie Haslem ◽

Greg J. Holland ◽

Steven W. J. Leonard ◽

Josephine MacHunter ◽

...

Keyword(s):

Environmental Gradients ◽

Fire Regimes ◽

Plant Distributions ◽

Eucalypt Forests

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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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Phenotypic plasticity can reverse the relative extent of intra- and interspecific variability across a thermal gradient

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2021.0428 ◽

2021 ◽

Vol 288 (1953) ◽

pp. 20210428

Author(s):

Staffan Jacob ◽

Delphine Legrand

Keyword(s):

Phenotypic Plasticity ◽

Thermal Gradient ◽

Environmental Gradients ◽

Intraspecific Variability ◽

Functional Trait ◽

Ecosystem Functions ◽

Interspecific Variability ◽

Ciliate Species ◽

Relative Extent ◽

Trait Variability

Intra- and interspecific variability can both ensure ecosystem functions. Generalizing the effects of individual and species assemblages requires understanding how much within and between species trait variation is genetically based or results from phenotypic plasticity. Phenotypic plasticity can indeed lead to rapid and important changes of trait distributions, and in turn community functionality, depending on environmental conditions, which raises a crucial question: could phenotypic plasticity modify the relative importance of intra- and interspecific variability along environmental gradients? We quantified the fundamental niche of five genotypes in monocultures for each of five ciliate species along a wide thermal gradient in standardized conditions to assess the importance of phenotypic plasticity for the level of intraspecific variability compared to differences between species. We showed that phenotypic plasticity strongly influences trait variability and reverses the relative extent of intra- and interspecific variability along the thermal gradient. Our results show that phenotypic plasticity may lead to either increase or decrease of functional trait variability along environmental gradients, making intra- and interspecific variability highly dynamic components of ecological systems.

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Community assembly within ponds: the roles of space, time, and environmental gradients

Aquatic Ecology ◽

10.1007/s10452-021-09902-0 ◽

2021 ◽

Author(s):

Carmen G. Montaña ◽

Friedrich W. Keppeler ◽

Clay P. Laughrey ◽

Christopher M. Schalk

Keyword(s):

Community Assembly ◽

Environmental Gradients ◽

Space Time

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An Entangled Bank

Phylogenies in Ecology ◽

10.23943/princeton/9780691157689.003.0001 ◽

2016 ◽

Author(s):

Marc W. Cadotte ◽

T. Jonathan Davies

Keyword(s):

Evolutionary Theory ◽

Community Assembly ◽

Charles Darwin ◽

Neutral Theory ◽

Species Distributions ◽

Ecological Interactions ◽

Carl Linnaeus ◽

History Of ◽

Neutral Theory Of Biodiversity ◽

Diversity Of Life

This chapter reviews the history of the use of phylogenetics in ecology, beginning with a discussion of early attempts to classify the diversity of life and the development of evolutionary theory. In particular, it examines how early taxonomists, starting with Carl Linnaeus, have grouped species by similarity in their traits and how early ecologists and biologists such as Charles Darwin recognized the importance of relatedness in influencing ecological interactions and species distributions. The chapter proceeds by focusing on the introduction of the neutral theory of biodiversity into mainstream ecology and the development of the niche-based model of community assembly. It also considers how some ecologists questioned the relevance of phylogenetic corrections for ecology and concludes by analyzing the emergence of ecological phylogenetics or ecophylogenetics.

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