Rewiring food webs via trophic rewilding

During late Quaternary, humans caused mass extinctions of vertebrates, with a selective size-bias towards large mammals, likely causing losses of top-down trophic processes within ecosystems. Trophic rewilding is a restoration strategy that promotes self-sustaining ecosystems via (re)introduction of species to restore top-down processes, but the extent of restoration possible is poorly understood. Here, we used current and estimated range maps of where terrestrial mammals would live today without human influences together with climatic suitability ranges of these same species to simulate a rewilding scenario. We then used network analysis to investigate the impact of extinctions on top-down control and the restoration potential of trophic rewilding. Our results suggest that terrestrial ecosystems lost on average 44% of trophic levels’ species composition and 47% of the links among trophic levels. However, rewilding can restore trophic links to 80% of their pre-extinction level, highlighting the potential of trophic rewilding for restoring self-sustaining ecosystems.