On the interplay of speciation and dispersal: An evolutionary food web model in space

• We analyze the interplay of evolution and dispersal in metacommunities.
• Locally, food webs evolve according to the model by Loeuille and Loreau (2005).
• By coupling these via migration links, we obtain food webs in a patchy environment.
• Random migration leads to familiar diversity–dispersal relationships.
• With adaptive migration, neighboring networks can become very different.

We introduce an evolutionary metacommunity of multitrophic food webs on several habitats coupled by migration. In contrast to previous studies that focus either on evolutionary or on spatial aspects, we include both and investigate the interplay between them. Locally, the species emerge, interact and go extinct according to the rules of the well-known evolutionary food web model proposed by Loeuille and Loreau (2005). Additionally, species are able to migrate between the habitats. With random migration, we are able to reproduce common trends in diversity–dispersal relationships: Regional diversity decreases with increasing migration rates, whereas local diversity can increase in case of a low level of dispersal. Moreover, we find that the total biomasses in the different patches become similar even when species composition remains different. With adaptive migration, we observe species compositions that differ considerably between patches and contain species that are descendant from ancestors on both patches. This result indicates that the combination of spatial aspects and evolutionary processes affects the structure of food webs in different ways than each of them alone.