Impacts of deglaciation on biodiversity and ecosystem function

Glaciers and glacially influenced ecosystems host unique biodiversity spanning all kingdoms of life, but glaciers are retreating as the global climate warms, threatening specialist species, ecosystem functions and stability. We outline the impacts and consequences of glacier retreat, identifying key drivers and mechanisms of change, focusing on biodiversity and interactions among glacier, terrestrial, freshwater and marine ecosystems. We identify global glacial biodiversity patterns and local nuances, highlighting taxa that are likely to thrive or decline with the loss of glaciers. Following glacier retreat, the availability and size of ice-free areas initially increase, leading to a ‘biodiversity peak’. However, as glaciers disappear, the formation of novel habitats decreases while communities become more homogeneous and competition increases, leading to local-to-regional biodiversity decline. Glacier loss impacts multiple ecosystem functions that contribute to climate regulation, freshwater resources, carbon and nutrient cycling, soil development, primary productivity, and food web stability. Key challenges in glacier ecosystem science include advancing knowledge of the relationships between biodiversity and ecosystem functions and quantifying species interactions at local-to-global scales to improve mechanistic understanding. Such advances will enhance prediction of how biodiversity will change with the loss of glaciers, enabling informed and effective conservation and management.