Meso-Carnivore Niche Expansion in Response to an Apex Predator's Reintroduction - a Stable Isotope Approach

Apex predatorscan have considerable impacts on meso- carnivorediets, through competition or facilitation. Facilitation occurs when smaller predatorsconsume carrioncreated by larger predators, especially large-bodied prey species normally inaccessible to meso- carnivores. In contrast, apex predatorscan also negatively affect meso- carnivoreconsumption of important resources through competitive interactions. Thus, predicting meso- carnivoreresponses to trophic structure changes (i.e. apex predatorextirpation or reintroduction) is often difficult. We investigated stable carbon and nitrogen isotope nichebreadths of black-backed jackal( Canis mesomelas) in response to the reintroduction of an apex predator, the African lion ( Pantheraleo), to the Karoo National Park, South Africa. Jackalfaecal isotopic nichewidths were larger in post-lion than pre-lion samples, indicating a nicheexpansion to include pure C3- and C4-based food sources when lions were present. Most prey items of this nature in the study ...