Who's hot and who's not: ocean warming alters species dominance through competitive displacement

Abstract

Species interactions have received little attention in climate-change studies, yet these interactions are fundamental to the functioning of ecosystems. Milazzo et al. () combined field surveys and controlled experiments to show how increasing abundance of a range-extending species and ocean warming interactively affect the habitat occupancy of two co-occurring species with similar habitat preferences. The authors found that in warmer conditions the ‘cool-water’ species is competitively displaced from preferred algal habitat to sub-optimal seagrass habitat, but only at higher densities of the warm-water species. Their results provide an important first step for unravelling how simple species interactions can create novel communities.