LETTER doi:10.1038/nature11318

Averting biodiversity collapse in tropical forest protected areas A list of the authors and their affiliations appears at the end of the paper. The rapid disruption of tropical forests probably imperils global bio-diversity more than any other contemporary phenomenon1–3. With deforestation advancing quickly, protected areas are increasingly becoming final refuges for threatened species and natural ecosystem processes. However, many protected areas in the tropics are them-selves vulnerable to human encroachment and other environmental stresses4–9. As pressures mount, it is vital to know whether existing reserves can sustain their biodiversity. A critical constraint in addressing this question has been that data describing a broad array of biodiversity groups have been unavailable for a sufficiently large and representative sample of reserves. Here we present a uniquely comprehensive data set on changes over the past 20 to 30 years in 3