Response of a carnivore community to water management in a semi-arid savanna

Abstract

Water is a limiting and important resource for large herbivores in arid and semi-arid ecosystems. Consequently, provision of artificial water is often used to alleviate limited surface water during dry periods. When foraging, large carnivores benefit from herbivore aggregation around water sources. Large carnivore attraction to areas of high water and prey availability is likely to affect smaller carnivores at these sites through competitive interactions. Here, we explore the effect of water management on the structure and the asymmetric interactions of an African carnivore community using data from camera trapping surveys. We used a functional approach based on four ranks driven by species body size (rank 1: African lions, spotted hyaenas; rank 2: leopards, African wild dogs, brown hyaenas, cheetahs; rank 3: African civets, black-backed and side striped jackals, caracals, honey badgers, servals; rank 4: African wildcats, large spotted genets, striped polecats, mongoose species), and performed multispecies occupancy models and activity pattern analyses. Results show that distance to water influences rank marginal occupancy probabilities with first- and third-ranked species more likely to use sites closer to water while we observed the opposite for second- and fourth-ranked species. However, while marginal occupancy patterns could suggest spatial avoidance, conditional occupancy of a given rank depending on another shows a constant and positive effect of the presence of a higher rank on conditional occupancy of its subordinate rank. Additionally, activity pattern analyses showed some shifts in peaks of activity in some subordinate ranks, although independent from water availability. This work shows that provision of artificial water contributes to shaping the structure of carnivore communities, and we encourage managers to account for these findings. Specifically, ensuring heterogeneity in the distances to waterholes across the landscape will favour a higher diversity of carnivores at the landscape scale.