Integrating biogeography and food web ecology to understand the influence of species diet breadth on their range size.

Understanding species range distributions and the mechanisms regulating them is at the basis of fundamental knowledge on species vulnerability to extinction.

Large part of the research devoted to understand these patterns have focused on the influence of environmental factors, ignoring the potential effect of trophic interactions.

Conversely, food web research have mostly put their attention into local scale analyses ignoring the influence of biogeographical processes in structuring ecological networks. An evident gap thus exists between biogeographical and food web studies.

BIOFOODWEB aims at bridging this gap by disentangling the influence of species interactions in determining species geographical range size (i.e. the extent of its spatial distribution). Species range size is a central aspect of biogeographic research.

Multiple studies have used species traits, such as body size or niche breadth (i.e., the set of environments or resources that it can inhabit or use), to explain the variation in range size across species.

While some dimensions of the niche, such as environmental tolerance, have been used as predictors of species range size, the influence of diet breadth (i.e., set of interacting partners a species has) has been seldom explored. This proposal aims to identify the importance of species biotic interactions in determining species range size.

Previous attempts to test the relationship between species diet breadth and range size were restricted to small geographical areas or reduced taxonomic groups.

For the first time, BIOFOODWEB will unravel the geographical variation in the relationship between species diet breadth and range size across multiple taxonomic groups and across spatial scales by using large-scale datasets that contain information on both species distributions and their trophic interactions.

Such a general understanding will help us to better evaluate and predict species vulnerability to extinction under rapid environmental change.