Betts, Matthew G.; Yang, Zhiqiang; Hadley, Adam S.; Smith, Adam C.; Rousseau, Josée S.; Northrup, Joseph M.; Nocera, Joseph J.; Gorelick, Noel; Gerber, Brian D. 2022. Forest degradation drives widespread avian habitat and population declines. Nature Ecology & Evolution. 6(6): 709-719. doi:https://doi.org/0.1038/s41559-022-01737-8
In many regions of the world, forest management has reduced old forest and simplified forest structure and composition. We hypothesized that such forest degradation has resulted in long-term habitat loss for forest-associated bird species of eastern Canada (130,017?km2) which, in turn, has caused bird-population declines. Despite little change in overall forest cover, we found substantial reductions in old forest as a result of frequent clear-cutting and a broad-scale transformation to intensified forestry. Back-cast species distribution models revealed that breeding habitat loss occurred for 66% of the 54 most common species from 1985 to 2020 and was strongly associated with reduction in old age classes. Using a long-term, independent dataset, we found that habitat amount predicted population size for 94% of species, and habitat loss was associated with population declines for old-forest species. Forest degradation may therefore be a primary cause of biodiversity decline in managed forest landscapes.