Quantifying the predation impact of an expanding mesocarnivore on declining small-game species

Abstract

Human-wildlife conflicts have increased and are particularly acute when predators are involved. A frequent source of conflict is some people's misbeliefs related to the alleged impact of predators on game species and livestock. In this context, quantifying the impact of expanding predators on their prey can be useful in designing conflict mitigation strategies. We estimated the predation impact of the Egyptian mongoose (Herpestes ichneumon), an expanding mesocarnivore in southwestern Europe, on European rabbit (Oryctolagus cuniculus) and red-legged partridge (Alectoris rufa) populations, two declining prey species highly valued by hunters. We estimated mongoose densities in three areas of central Spain through live capture, GPS/VHF tagging, camera-trapping and spatial mark-resight models. Rabbit and partridge densities were estimated through transect counts and distance sampling. We quantified the mongoose diet by scat analysis. Finally, we compared the number of individuals consumed by the predator population with the estimated total prey populations. European rabbits were the most important mongoose food in two of the study areas, whereas red-legged partridges were rarely consumed in all the areas. Rabbit density varied widely among study areas (14.0–881.4 rabbits/km²), while partridge density was low in all the areas (2.3–6.9 partridges/km2). The predation impact on rabbits was low in the area with the highest rabbit density (1.9–3.8% of estimated population) and higher (5.6–29%) in the other areas. In contrast, the predation impact on partridge populations was low (<9%) in all the study areas. This is the first study that estimates the Egyptian mongoose impact on small-game species, a necessary step to deal with the conflicts over the management of this expanding species. The study of predation impact may contribute to the effective management of human-wildlife conflicts involving predators, by improving the understanding of where additional management may take place to protect prey species or deter predator populations.