Conserving biodiversity is an imperative for the twenty-first century, but current knowledge is insufficient for this to be done effectively. This theme will develop knowledge of the patterns, causes and measurement of changes in biodiversity in the context of global human influence. This includes studies of biodiversity decline, the current distribution and function of biodiversity, ecological processes that underlie resilience and recovery, effective ways of managing and monitoring these processes, and the mixes of land uses within a landscape that can both sustain desired elements of biodiversity and support production and human occupancy. Much of this work will focus on tropical and subtropical ecosystems, for which the knowledge base is currently inadequate, and there are good prospects for internationalisation. All research areas have a strong interface with socio-economic and policy issues, with a high potential for interaction with the Centre's other four themes.