Emergent patterns of island biodiversity in the Anthropocene

Islands have long been foundational to the development of ecological and evolutionary theory, serving as model systems for studying patterns of biodiversity. However, pervasive anthropogenic impacts-particularly species extinctions and introductions-have substantially altered island ecosystems, complicating inferences drawn from contemporary data. Here, we review how these human-driven changes have reshaped key biodiversity patterns on islands, including patterns of species richness, community composition, evolution, and species interactions. We show that many current ecological and evolutionary patterns observed on islands reflect not just natural processes but also a legacy of human-induced change spanning millennia. Approaches that better incorporate paleoecological evidence, along with improved island biodiversity databases and modeling techniques, can help better reconstruct prehuman biodiversity baselines on islands.