Assessment of the stream invertebrate β-diversity along an elevation gradient using a bidimensional null model analysis

Aim: β-Diversity, commonly defined as the compositional variation among localities that links local diversity (α‐diversity) and regional diversity (γ‐diversity), can arise from two different ecological phenomena, namely the spatial species turnover (i.e. species replacement) and the nestedness of assemblages (i.e. species loss). However, any assessment that does not account for stochasticity in community assembly could be biased and misinform conservation management. In this study, we aimed to provide a better understanding of the overall ecological phenomena underlying stream β-diversity along elevation gradients, and at contributing to the rich debate on null model approaches to identify non-random patterns in the distribution of taxa. Location: Swiss Alpine region. Methods: Based on presence-absence data of 78 stream invertebrate families from 309 sites, we analyzed the effect size of non-random spatial distribution of stream invertebrates on the β-diversity and its two components (i...