Forest disturbance from human activities can result in just as much biodiversity loss as deforestation, reveals an assessment of more than 2,000 species in the Brazilian Amazon published this week in Nature. The study calls for urgent regional-scale interventions that go beyond the maintenance of forest cover to protect the biodiversity of the world’s remaining tropical forests.
Reducing deforestation is the focus of most strategies for conserving biodiversity. Brazil’s Forest Code, for example, legally requires Amazonian landowners to maintain 80% of their forest cover. However, the combined effects of disturbances such as selective logging, wildfires and landscape alteration on the biodiversity of remaining forests have until now remained unknown.
Jos Barlow and colleagues assessed occurrence data of 1,538 plant, 460 bird and 156 dung beetle species throughout the Amazonian state of Para in northern Brazil. They find that although disturbed forests retained considerable conservation value, disturbance impacts had an equivalent effect on biodiversity as the loss of 92,000-139,000 km2 of primary forest outside of Para’s strictly protected areas. The authors conclude that even when deforestation is limited to the 20% required by law, the remaining forest may only retain 46-61% of its conservation value.
In an accompanying News & Views, David Edwards concludes: “Although the biodiversity extinction crisis could be even worse than currently recognized, by embracing better management strategies, the solutions are still within our grasp.”