Comparative diet and habitat selection of puku and lechwe in northern Botswana

Abstract

Differences in resource selection (i.e., habitat selection and diet composition) may allow for coexistence of interspecific competitors. Two congeneric floodplain antelope with broadly similar habitat use are puku (Kobus vardonii) and lechwe (K. leche). In Botswana, puku are restricted to a narrow band of floodplains along the Chobe River, whereas lechwe are far more abundant, with a distribution encompassing the Chobe Riverfront, the Linyanti Swamps, Kwando River, and the Okavango Delta. We investigated factors to try to explain the contrasting distribution patterns of puku and lechwe, including seasonal diet composition and overlap, seasonal nutritional status as indicated by fecal nitrogen and phosphorus, and habitat selection. Dietary overlap ranged from 84% to 90% across seasons. Cynodon dactylon was the greatest contributor to the diets of both puku and lechwe, but there were differences in the relative contributions of particular grass species associated with uplands or floodplains. Fecal nitrogen and phosphorus did not differ between species and did not indicate nutritional deficiencies for either puku or lechwe. Habitat selection was broadly similar during the low-water season, but during the high-water season, puku moved from the floodplain into shrublands habitats, whereas lechwe remained on the floodplains. We hypothesize that increased predation risk during the high-water season, due to increased visual obstruction in shrublands, may limit abundance of puku in the study area.