Ecological gatekeeping: Black-backed jackals are left to crave carrion in absence of large facultative scavengers

Abstract

Carrion removal is a key ecological function of scavengers, and they promptly dispose of carcasses in those large African conservation areas where predator assemblages remain intact. Despite its species richness, the grassland biome is critically threatened in southern Africa, and the predator assemblage is no longer intact in most of the biome. We used camera traps to monitor scavenger activity at five blue wildebeest (Connochaetes taurinus) carcasses on the Telperion Nature Reserve, characterized by rocky highveld grassland. We found that, in absence of larger vertebrate scavengers, black-backed jackals (Canis mesomelas) were unable to access fresh blue wildebeest carcasses, gaining access only once invertebrate action opened the skin. We also observed black-backed jackals eating flies accumulating on grass near to carcasses. These observations show that the avenues of resource provisioning by carcasses are not limited to direct carrion consumption. Moreover, they raise questions about potentially important cascading effects of not having intact predator assemblages, in smaller conservation areas.