Adaptive foraging behaviour increases vulnerability to climate change

Abstract

Adaptative foraging behaviour should promote species coexistence and biodiversity under climate change as consumers are expected to maximise their energy intake, according to principles of optimal foraging theory. We test these assumptions using a unique dataset comprising (1) 22,185 stomach contents of fish species across functional groups and feeding strategies and (2) prey availability in the environment over 12 years. We explore how foraging behavior responds to variance in ecosystem productivity and temperature. Our results show that foraging shifts from trait-dependent prey selectivity to simple density dependence in warmer and more productive environments. Contrary to classical assumptions, we show that this behavioural change leads to lower consumption efficiency as species shift away from their optimal trophic niche. Dynamic food-web modeling demonstrates that this behavioral response to warming could undermine species persistence and biodiversity. By integrating empirical adaptive foraging behavior into dynamic models, our study reveals higher risk profiles for ecosystems under global warming.