Warming indirectly increases invasion success in food webs

Climate warming and biological invasions are key drivers of biodiversity change. Their combined effects on ecological communities remain largely unexplored. We investigated the direct and indirect influences of warming on invasion success, and their synergistic effects on community structure and dynamics. Using size-structured food web models, we found that warming increased invasion success. The direct physiological effects of warming on invasions were minimal in comparison to indirect effects mediated by changes on food web structure and stability. Warmed communities with less connectivity, shortened food chains and reduced temporal variability were more susceptible to invasions. The directionality and magnitude of invasions effects on food webs varied across warming regimes. Warmer communities became smaller, more connected, and with more predator species when invaded than their colder counterparts. They were also less stable and their species more abundant. Considering food web structure is crucial to predict invasion success and its impacts under warming.