Robert Timmers and 15 other authors, in Frontiers in Ecology and the Environment, 2022:
Conservation of birds in fragmented landscapes requires protected areas (doi:10.1002/fee.2485)
The study involved nearly 2,000 bird species in over 700 habitat fragments worldwide.
From the Conclusion:
“In this global meta-analysis, we show that bird occurrence was significantly associated with fragment size, protection status, and matrix type. The impact of fragment size was larger than that of any other factor, highlighting the critical importance of large forest areas for conserving bird diversity.
We also found evidence that protection can be an effective strategy for preserving diversity in fragmented landscapes. For forest fragments >50 ha, strict protection (IUCN cate-gories I– IV) positively contributes to maintaining bird species. For forest-dependent species, even smaller fragments (>25 ha) are worth strict protection.
Under moderate protection, fragments must be >175 ha for protection to have a positive effect. The benefits of protection are especially evident for threatened species, for which strict protection of sufficiently large forest patches appears to be crucial.
Other avian species that benefit from the conservation of large forest fragments include insectivores, carnivores, and dispersive birds. In light of the ongoing debate about the conservation values of disturbed versus intact forests […], the results of our analysis provide additional support for the following position: the value of forest fragments should not be underestimated, but protection is required to slow or stop declines in bird species populations in fragmented forest landscapes.”