Revealing seasonal dietary niche overlap among sympatric large carnivores using DNA metabarcoding

Abstract

Understanding how large carnivores partition dietary resources is essential for assessing intra-guild competition and informing conservation strategies. In this study, we used DNA metabarcoding of scats to quantify and compare the diets of sympatric African lions (Panthera leo) and spotted hyenas (Crocuta crocuta) across wet and dry seasons in the Greater Etosha Landscape of Namibia. Across 98 scat samples (lion = 69; spotted hyena = 29), we identified 19 vertebrate prey species. Overall, large ungulates dominated both carnivores’ diets. For lions, the most frequent prey items included gemsbok (Oryx gazella), common eland (Taurotragus oryx), plains zebra (Equus quagga burchelli), and blue wildebeest (Connochaetus taurinus). For spotted hyenas, the most frequent prey items were plains zebra, gemsbok, springbok (Antidorcas marsupialis), and black rhinoceros (Diceros bicornis bicornis). Dietary niche breadth was not significantly different between species, though lions exhibited the broadest across both seasons, while diet composition was similar between species and seasons. However, the smaller sample size for spotted hyenas may limit full characterization of their diet and influence measures of overlap and niche breadth. These results suggest a moderate diet overlap and limited resource partitioning both within and among these large carnivore species across seasons, likely facilitated by opportunistic scavenging and kleptoparasitism. Both species exhibited broader dietary niche breadths during the wet season, likely reflecting increased prey availability and dispersion. Ongoing monitoring of carnivore diets using molecular tools, which provides a more accurate and comprehensive identification of diet items than manual sorting, will be essential for detecting changes in resource use and interspecific interactions in response to shifting environmental conditions and anthropogenic pressures.