Disturbance interacts with dispersal and niche breadth to shape scale-dependent diversity change in metacommunities

Disturbances influence the maintenance of diversity in important, but complex, ways across spatial and temporal scales. Although disturbance effects on diversity are known to be scale-dependent and taxon-specific, there is little mechanistic understanding of the processes that influence the observed context-dependency. Here, we take a theoretical approach based on metacommunity theory to examine the interaction between metacommunity processes and disturbance in shaping diversity patterns across spatial scales. We find that disturbance shapes diversity at local and regional scales in ways which can lead to either homogenization (decreases in β -diversity) or differentiation (increases in β -diversity). How it does so depend on the spatial extent of the disturbance in the landscape, the dispersal rates and niche breadth of species in the metacommunity, and whether diversity is measured immediately following disturbance or during recovery.We show that high dispersal jointly promotes the rapid recovery of local diversity and the loss of regional diversity, resulting in decreases in β -diversity. Niche breath buffers against diversity loss at both scales during disturbance, but interacts with dispersal to drive transient diversity loss at the regional scale after disturbance. Our results suggest that particular processes in metacommunities interact with disturbance and leave behind distinct signatures of diversity change across scales that can be used to better parse observed patterns of diversity change in empirical systems.