High β‐diversity maintains regional diversity in Brazilian tropical coastal stream fish assemblages

Abstract

AbstractUnderstanding spatial patterns of species diversity and the variables that structure biological communities is critical to successful ecosystem management. Regional diversity (γ) can be considered a combination of local diversity (α) and among sites variation (β). Using abundance data of fish species in 19 stream stretches, an analysis of diversity partitioning was used to determine the contribution of α‐ and β‐diversity to γ‐diversity. Redundancy analysis was applied to find the contribution of environmental variables and spatial configuration to species composition. Intersite variation contributed significantly to γ‐diversity. Spatial configuration and instream heterogeneity (coarse substrate, channel width, water velocity and shading) and riparian vegetation were related to local fish abundances. Conservation actions should consider that all streams are important, and prioritisation of just a small number of the richest sites is not appropriate.