Virginia Institute of Marine Science
1. When investigating metacommunity dynamics, functional differences among
species are often assumed to be as important as environmental differences be-
tween sites in determining β-diversity. However, few studies have examined the
influence of functional diversity on β-diversity. We examine the relative importance of regional functional diversity partitioned by niche dimensions and environmental variation in structuring taxonomic β-diversity of stream fishes using a large dataset of stream fish assemblages (hereafter, simply β-diversity). We predicted that both functional diversity and environmental variation play a rolein determining β-diversity.
2. We tested this prediction by modelling the patterns of stream fish β-diversity as
a function of environmental variation, functional diversity and γ- richness across
10,220 sites for 329 fish species using a series of conceptual path models.
3. Environmental variation consistently affected β-diversity across all models,
whereas functional diversity and γ- richness influenced β-diversity only in some
models. We show that including relevant trait differences among species in path
models can improve their ability to explain β-diversity, suggesting that functional traits influence β-diversity.
4. The ability of path models to explain β-diversity varied depending on the trait
grouping included in the model, demonstrating that specific path models representing different niche dimensions can improve the ability of a model to explain β-diversity. In addition, parsing traits into different niche dimensions revealed alternative patterns of functional diversity–β-diversity relationships that other-wise would have been missed.
5. The selection of relevant traits and linked niche dimensions is critical for detecting relationships between functional diversity and β-diversity. Using traits
associated with different niche dimensions allows for the identification of niche
dimensions most strongly associated with species sorting and the detection of
patterns missed by focusing on a single niche dimension. Determining the niche dimensions that influence β-diversity could provide insights into the processes
driving biodiversity and metacommunity dynamics, improving our ability to con-
serve or restore aquatic communities.
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Bower, Luke M.; Stoczynski, Lauren; Peoples, Brandon K.; Patrick, Christopher J.; and Brown, Bryan L., Multiple dimensions of functional diversity affect stream fish taxonomic β-diversity (2022). Freshwater Biology.