Document Type



Virginia Institute of Marine Science

Publication Date



Freshwater Biology

First Page


Last Page



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.


DOI: 10.1111/fwb.14036

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.