Dataset - Core reorganisation in food webs buffers ecosystems against warming

Food webs are central to ecosystem functioning and stability, yet how they respond to climate warming at the substructural level remains unclear. We investigated how warming governs the core–periphery organisation of food webs, and how changes in this substructure mediate impacts on ecosystem functioning (energy flux) and stability (robustness) across a natural stream temperature gradient in Iceland. The size of the core remained consistent across temperatures, but there was marked turnover in the abundance and identity of core species. While warming consistently decreased robustness to secondary extinctions through reduced food web connectance, core reorganisation enhanced both energy flux and robustness to species loss. Dynamic modelling revealed that ecosystems were disproportionately more sensitive to the loss of core taxa, highlighting the importance of maintaining core size for ecosystem stability. These results demonstrate important stabilising features of food webs that could mitigate the negative impacts of climate warming. Our findings underscore the importance of considering substructural dynamics for predicting ecological responses to climate change.