Ecological processes shaping Antarctic terrestrial biodiversity change

Antarctica’s compositionally and functionally unusual biodiversity is typically neglected in global biodiversity analyses, and ecological theory is rarely applied in the Antarctic context. These omissions mean that predictions of the future of Antarctic biodiversity under global change are weakly guided by mechanistic understanding. In this Perspective, we provide an overview of Antarctica’s biodiversity and key changes in its terrestrial environment and then discuss how five central ecological processes (abiotic filtering, dispersal, adaptation, biotic interactions and stochasticity) are affecting biodiversity on the continent. On the basis of the evidence supporting each of these processes, we establish five non-exclusive hypotheses for terrestrial Antarctic biodiversity outcomes under global change: constrained, dynamic, disordered, diversifying and interactive. Available evidence best supports the constrained hypothesis, in which abiotic conditions will probably remain a dominant constraint to fitness, even in warmer, wetter conditions. The five biodiversity outcomes we articulate provide theory-driven, testable hypotheses for Antarctic biodiversity and identify priority knowledge gaps to reduce uncertainty about its future.