Important areas for the conservation of the European Roller Coracias garrulus during the non-breeding season in southern Africa

Abstract

The identification of threats to migratory species of conservation concern and the relevance of protected areas for them is often biased towards breeding areas. The European Roller Coracias garrulus is a long-distance migrant experiencing a pronounced decline throughout its breeding range, which has been attributed to the degradation of open agricultural habitats. However, its conservation status in non-breeding areas in Africa remains unstudied. Land cover change is a major threat affecting migratory birds in their wintering grounds, therefore identifying important areas for their protection at this stage is a priority. Here we used occurrence data during the wintering season and ecological niche models to identify key land cover and areas used by Rollers in Africa. First, we used 33 filtered locations from six satellite-tracked birds breeding in Spain to describe suitable wintering areas for the Spanish population (westernmost part of the Eurasian breeding range). We also used 1,167 occurrence data in southern Africa from open-access databases and bird atlases to characterise the overall wintering range of the species. The Spanish population occupied a relatively small area in the north-western part of southern Africa, and a narrow range of land covers. Open grassland, less steep areas and those with sparse tree cover are correlated with suitability. In all, 18.06% of suitable wintering areas for the Spanish population overlapped with protected areas. The overall population of Rollers occupied a wider area and range of land cover. Tree cover was the most important variable affecting suitability, with areas without tree cover being the least suitable. We found that 9.58% of suitable wintering areas for the overall population overlapped with protected areas. Our results suggest that Rollers from different origins (breeding populations) use separate, but overlapping, wintering areas and may have different habitat requirements, and therefore, population-specific conservation strategies in these areas might be needed to fully protect the species.