African wild dogs (Lycaon pictus) show differences in diet composition across landscape types in Kruger National Park, South Africa

Abstract

The Kruger National Park (KNP) is home to the last genetically viable, minimally managed population of African wild dogs (Lycaon pictus, wild dogs) in South Africa. Until 2004, this population remained stable, but since has been declining. In this study, we aimed to improve our understanding of the ecology of KNP wild dogs by estimating the relative contribution of different prey types to their diet across landscape types. Based on a Bayesian mixing model, we assessed wild dog diet and foraging preferences using stable isotope analysis. We sampled 73 individuals from 40 packs found in six different landscape types. In thickets, packs predominantly prey on small browsing and mixed-feeding species (accounting for ~73% of their diet), but occasionally hunt large grazers (~24%) and large browsers (~3%). In open landscape types where lions (Panthera leo) are more or less absent, such as in the Lowveld sour bushveld, wild dogs prey on large browsers and large grazers (~67%). Our results demonstrate that KNP wild dogs occupy a broader ecological niche than previously thought, with small browsers forming an integral part of their diet. We also present the first data describing differences in wild dog diet–tissue discrimination factors for tail hair and whiskers compared to respective stable nitrogen (δ15N) and carbon (δ13C) values obtained from feces of captive wild dogs, as well as from those of South Africa’s broader managed metapopulation. While these data should be considered preliminary, we suggest that until wild dog diet–tissue discrimination factors are calculated through a controlled feeding study, the discrimination factors calculated for the gray wolf (Canis lupus) should be used for wild dog-related isotope studies, rather than the often cited values for red foxes (Vulpes vulpes).

Nitrogen isotopic composition of tooth enamel organic matter records trophic position in modern and fossil ecosystems

“…Leopards, for example, prefer relatively small prey (e.g., body mass 10 to 40 kg) which occur in dense habitats; for example, impala, bushbuck, and common duiker, while larger prey and species restricted to open vegetation are generally avoided 81 . Similarly, wild dogs tend to hunt in areas of denser vegetation and target browsing and mixed feeding herbivores in regions where they co-occur with hyenas and lions 82 . Lions and hyenas, in contrast, have higher δ 13 Cenamel values, consistent with the consumption of a greater proportion of grazing taxa (i.e., C4-consuming prey) which occupy more open environments.…”

Tooth enamel nitrogen isotope composition records trophic position: a tool for reconstructing food webs

“…Leopards, for example, prefer relatively small prey (e.g., body mass 10 to 40 kg), which occur in dense habitats; for example, impala, bushbuck, and common duiker, while larger prey and species restricted to open vegetation are generally avoided 78 . Similarly, wild dogs tend to hunt in areas of denser vegetation and target browsing and mixed-feeding herbivores in regions where they co-occur with hyenas and lions 79 . Lions and hyenas, in contrast, have higher δ 13 C enamel values, consistent with the consumption of a greater proportion of grazing taxa (i.e., C 4 -consuming prey) which occupy more open environments.…”

African wild dogs (Lycaon pictus) from the Kruger National Park, South Africa are currently not inbred but have low genomic diversity

“…When considering the significant decline of African wild dog numbers from an estimated 500,000 in 1900, to 6600 today (4), we expect that any African wild dog population would have reduced levels of genome variation. Although the KNP population is the only viable population in South Africa, it is largely unmanaged 1 , 44 , and we expect to observe low levels of genomic diversity. Based on the sample availability for WGS, which mostly included samples from the alpha female and male of different packs, we expect to observe distant relatedness and low levels of inbreeding, since we expect that the alpha pair would mostly be unrelated.…”