Long-term effects of rewilding on species composition: 22 years of raptor monitoring in the Chernobyl Exclusion Zone

Large-scale rewilding has been proposed as an effective method to combat the global biodiversity crisis, although there is a lack of data to support this. Rewilding generally refers to a process that allows nature to recover by reducing human interference, without the predefined end-goal that more traditional restoration projects usually have. The Chernobyl Exclusion Zone (CEZ) is perhaps the most famous example of passive rewilding (rewilding with little or no management), but until now, most research has focused on the impact of radiation on wildlife rather than on rewilding. Here, we analyze species composition change of raptors in the Belarusian CEZ over a 22-year period, starting 12 years after the accident, alongside national raptor monitoring data. Generalist and farmland-associated mesopredators, super-abundant at the beginning of our study, strongly declined, as open habitats (former agricultural land) rewetted or became overgrown. Increase in waterlogged areas saw wetland specialists increase in abundance, including two species locally extinct from the area before the accident: Greater Spotted Eagle (Endangered in Europe) and White-tailed Eagle. Greater Spotted Eagles are an indicator of wetland habitat quality, and while declining throughout Europe in recent decades, they have increased from zero to at least 13 pairs, over the whole Belarusian CEZ. Our research is evidence that rewilding could be an effective way of restoring species and species interactions found in near-natural habitats, and if human interferences in ecological processes are reduced, a priori restoration goals and continued management are not always necessary to conserve threatened species.