The value of protected areas to avian persistence across 20 years of climate and land-use change.

Establishing protected areas, where human activities and land cover changes are restricted, is one of the most widely used strategies for biodiversity conservation. This practice is based on the assumption that protected areas buffer species from processes that drive extinction. However, the ability of protected areas to maintain biodiversity in the face of climate change and subsequent shifts in distributions has been questioned. Our goal was to evaluate the degree to which protected areas influenced colonization and extinction patterns for 97 avian species over 20 years in the northeastern United States. We fit single-visit dynamic occupancy models to Breeding Bird Atlas data to quantify drivers of local colonization and extinction in heterogeneous landscapes that varied in the amount of area under protection. Colonization and extinction probabilities improved with increasing amounts of protected area, but these effects were conditional on landscape context and species characteristics. In this forest-dominated region, benefits of additional land protection were greatest when both forest cover in a grid square and amount of protected area in neighboring grid squares were low. Effects did not vary with species' migratory habit or conservation status. Increasing amounts of land protection benefitted species at range margins but not core-range species. The greatest improvements in colonization and extinction rates accrued for forest birds compared to open habitat or generalist species. Overall, protected areas had a greater impact on stemming extinctions than promoting colonizations. Our results indicate that land protection remains a viable conservation strategy despite changing habitat and climate since protected areas both reduce the risk of local extinction and facilitate movement into new areas. Our findings suggest conservation in the face of climate change favors creation of new protected areas over enlarging existing ones as the optimal strategy to reduce extinction and provide stepping-stones for the greatest number of species. This article is protected by copyright. All rights reserved.