Cascading extinctions and ecosystem functioning: contrasting effects of diversity depending on food web structure

Abstract

The consequences of species loss on cascading extinctions in food webs have been the focus of several recent theoretical studies, with differing results. Changes in ecosystem properties consecutive to cascading extinctions have received far less attention even though such dramatic events might strongly alter ecosystem functioning. Here we use various food web models to investigate the effects of species loss and diversity on both secondary extinctions and their associated changes in ecosystem properties. Our analysis shows that diversity has contrasting effects depending on the presence of self‐limiting terms at consumer levels and, to a lower extent, on connectance and interspecific competition. Ecosystems that lose a high proportion of species through cascading extinctions exhibit the most important changes in ecosystem properties. Linking studies on cascading extinctions in food webs with studies that investigate the effects of biodiversity on ecosystem functioning appears crucial for a better understanding of the consequences of species extinctions.