Foraging Ecologies of Giraffe and Camels in Northern Kenya: Effects of Habitat Structure and Possibilities for Competition?

Abstract

Domestic camels (Camelus dromedarius) have become increasingly popular livestock in arid regions of sub-Saharan Africa. However, little is known about the environmental impacts of these animals, and concern has been mounting about possible competition with wild native ungulates. Unlike the more traditional pastoralist livestock species, camels are large-bodied, long-necked browsers which increases the potential to overlap with wild giraffe foraging, especially as the space available for browsing decreases. Giraffe ecology and social dynamics are poorly understood; it is believed that reticulated giraffe (Giraffa camelopardalis reticulata) population is in decline, and the effects of introducing a new potential competitor could be an added stressor. This study examines the foraging ecologies of reticulated giraffe and domestic camels in the Laikipia District of Kenya, an area where these two species have not been sympatric until very recently. Both wild giraffe and domestic camel foraging heights and food species were quantified using multi-metric observations. Using repeated two-minute group scans I recorded feeding height categories and plant food preferences. Transects were used to sample the vegetation in areas in which foraging observations were recorded. The results indicate that domestic camels do not overlap with giraffe in feeding heights. Not only do camels feed below giraffe, the two species also do not overlap in plant food preferences. Giraffes do not exhibit sexual dichotomies in plant food preferences. However, giraffes do exhibit sexual dichotomy in foraging heights, with females feeding at lower elevations than males. Habitat type has an effect on foraging ecologies of both giraffe sexes, but it is most pronounced in males; in contrast, habitat did not influence camel foraging. Such differences may be driven by local habitat structure and plant densities rather than by differing preferences between camels and giraffe. In addition, camel herder husbandry techniques also influence the dynamics of camel foraging by determining where and for how long camels browsed. These results have implications for the conservation and management of both species and the wider ecosystem if the twin goals of wildlife conservation and livestock production are to be achieved.