Global loss of climate connectivity in tropical forests

Abstract

Range shifts are a crucial mechanism enabling species to avoid extinction under climate change1,2. The majority of terrestrial biodiversity is concentrated in the tropics3, including species considered most vulnerable to climate warming4, but extensive and ongoing deforestation of tropical forests is likely to impede range shifts5,6. We conduct a global assessment of the potential for tropical species to reach analogous future climates—‘climate connectivity’—and empirically test how this has changed in response to deforestation between 2000 and 2012. We find that over 62% of tropical forest area (~10 million km2) is already incapable of facilitating range shifts to analogous future climates. In just 12 years, continued deforestation has caused a loss of climate connectivity for over 27% of surviving tropical forest, with accelerating declines in connectivity as forest loss increased. On average, if species’ ranges shift as far down climate gradients as permitted by existing forest connectivity, by 2070 they would still experience 0.77 °C of warming under the least severe climate warming scenario and up to 2.6 °C warming for the most severe scenario. Limiting further forest loss and focusing the global restoration agenda towards creating climate corridors are global priorities for improving resilience of tropical forest biotas under climate change. Physically connected habitats are required for terrestrial species to shift their liveable ranges as the tropics warm. The authors show that over half of tropical forest area is currently unable to provide such climate connectivity, and that loss of connectivity is accelerating with deforestation.