Long-term effects of rewilding on species composition: 22 years of raptor monitoring in the Chernobyl Exclusion Zone
Author(s): Dombrovski, V.C., Zhurauliou, D.V. & Ashton-Butt, A.
Published: January 2022
Journal: Restoration Ecology
Digital Identifier No. (DOI): 10.1111/rec.13633
Over 2,000 km² of Belarus previously given over to intensive agriculture and dense settlements was affected by the 1986 reactor meltdown at the Chernobyl Nuclear Plant in Ukraine. Since then, this area has experienced little to no human disturbance, leading to decades of ‘passive rewilding’ where nature has been left to its own devices.
This study explores the effects of this passive rewilding on the bird of prey community inhabiting the area; birds of prey sit at the top of the food chain and are thus excellent indicators of ecosystem health. The authors used a long-term dataset developed from periodic surveys of breeding birds of prey within a 147 km² study plot towards the edge of the Belarusian Chernobyl Exclusion Zone (CEZ).
The researchers also used satellite imagery to analyse changes in land cover throughout this period, finding significant shifts in the area occupied by different types of habitat over time. Former agricultural land either became overgrown or rewetted, and the increase in waterlogged areas saw wetland specialists increase in abundance. Two wetland specialist that had been locally extinct in the area prior to the accident – Greater Spotted Eagle and White-tailed Eagle – both returned and increased in number.
The study also followed the populations of 12 other raptor species from 1998 to 2019. Different species assemblages – the abundance and type of species present in an area – are associated with different habitats. Analysing the changes in abundance showed a decline in generalist predators, such as Montagu’s Harrier and Buzzard, which hunt over open fields and farmland and eat a variety of prey species, and an increase in specialists such as Greater Spotted Eagles and Hobby.
Because some of the specialists are dependent on other important conservation species for food, for example Corncrake and Great Snipe, this change indicates a positive impact of rewilding on the ecosystem as a whole, not just the raptor populations, and shows rewilding’s potential value as a strategy to tackle biodiversity loss.
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 focussed on the impact of radiation on wildlife rather than rewilding. Here, we analyse species composition change of raptors in the Belarusian CEZ over a twenty-two year period, starting twelve 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 whilst declining throughout Europe in recent decades, they have increased from zero to at least thirteen 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.
VCD would like to thank his supervisor Nikiforov M.E., the Directorate of the Polesie State Radiation-Ecological Reserve for assistance in carrying out the work, as well as to the colleagues who helped in the field work: P.Pinchuk, P.Pakul and M.Koloskov. AAB would like to acknowledge support from the Endangered Landscapes Programme. The programme/ELP is managed by the Cambridge Conservation Initiative and is funded by Arcadia, a charitable fund of Peter Baldwin and Lisbet Rausing.
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