The global reorganisation of island ecosystems

Island ecosystems are undergoing rapid reorganisation, yet the extent to which these changes exceed historical limits remains unclear. Here, we integrate pollen records with curated datasets of plant extinctions and island attributes to quantify ecological novelty, homogenisation, and biodiversity loss across global island systems. By comparing recent community states to their historical range of variability, we identify when ecosystems shift beyond past behaviour and assess associated changes in structure and composition. We show that many islands entered novel states during the Late Holocene, coinciding with increasing extinctions, canopy destabilisation, and widespread shifts toward herbaceous dominance.  These results highlight the central role of human activity in shaping novel biodiversity trajectories in the Anthropocene.