Ecological–economic optimization of biodiversity conservation under climate change

Substantial investment in climate change research has led to dire predictions of the impacts and risks to biodiversity. The Intergovernmental Panel on Climate Change fourth assessment report1 cites 28,586 studies demonstrating significant biolog-ical changes in terrestrial systems2. Already high extinction rates, driven primarily by habitat loss, are predicted to increase under climate change3–6. Yet there is little specific advice or precedent in the literature to guide climate adaptation in-vestment for conserving biodiversity within realistic economic constraints7. Here we present a systematic ecological and economic analysis of a climate adaptation problem in one of the world’s most species-rich and threatened ecosystems: the South African fynbos. We discover a counterintuitive optimal investment strategy that switches twice between options as the available adaptation budget increases. We demonstrat