BIODIVERSITY ON OCEANIC ISLANDS - ITS ORIGIN AND EXTINCTION

The isolation and small size of oceanic islands make them attractive m odels for studies of diversification; the sensitivity of their biota m akes them important subjects for studies of extinction. I explore the origin of island biotas through dispersal and in situ diversification, and examine the fate of these biotas since human contact. Island biot as start out depauperate and disharmonic, facilitating the survival of relict taxa and stimulating adaptive radiations. The often highly res tricted range and small population size of insular species, together w ith their limited diversity of defenses, make island biotas particular ly vulnerable to extinction, largely through habitat loss or interacti ons with introduced species.