Distribution of avian scavengers inside and outside of protected areas: contrasting patterns between two areas of Spain and South Africa

Abstract

Protected areas are central to the conservation of biodiversity across the globe. However, their performance, especially in relation to highly mobile species, is largely dependent on the socio-ecological characteristics of the landscape that surrounds them. Here, we assess the patterns of avian scavenger distribution, including both obligate (i.e., vultures) and facultative (corvids and other raptors) scavenger species, inside and outside of protected areas. We contrast the situation between an African area, which has protected areas surrounded by mostly subsistence stockbreeding (KwaZulu-Natal Province, South Africa) and a European area, which has protected areas surrounded by commercial farming (Ebro Valley, Spain). We found large differences between the two areas. In the South African area, the richness and abundance of vultures, but not of facultative scavengers, were higher inside than outside of protected areas; as a result, the richness and abundance of vultures were negatively related to the distance to the nearest protected area in South Africa. In contrast, the richness and abundance of vultures in the Spanish area were similar inside and outside of protected areas. We obtained similar results when focusing solely on presence and abundance of Gyps vultures. The contrasting effects of protected areas in the distribution of avian scavengers, especially vultures, in the studied areas may be due to differences in agro-systems and socio-economical models that lead to differential availability of ungulate carcasses. We suggest that carrion shortage in the subsistence farming systems in the South African area, whereby domestic livestock carcasses are generally used by householders and thus rarely become available to vultures, should be considered alongside poisoning prevention to help conserve African vulture populations.