Author(s): Joseph O Ogutu, Samule Andanje, Paula Kahumbu, Helen Gichohi, Robin S Reid, Shem C Kifugo, Mohammed Y Said, HansPeter Piepho, Norman OwenSmith
There is mounting concern a bout declines in wildlife populations in many protecte d areas in Africa. Migratory ungulates are especially vulnera ble to impacts of changing land use outside protected areas on their abundance. Range compression may compromise the capacity of migrants to cope with climatic variation, and accentuate both competitive interactions and predation. We analyz ed the population dynamics of 11 ungulate sp ecies within Kenya’s Nairobi National Park, and compared them to those in the adjoining Athi-K aputiei Plains, where human se ttlements and other develop- ments had expanded. The migratory wildebeest decrease d from almost 30,000 animals in 1978 to around 5,000 currently but the migratory zebra changed little regionally. Hartebeest , impala, eland, Thomson’s gazelle, Grant’s gazelle, water- buck, warthog and giraffe numbers declined regionally, whereas buffalo numbers expanded. Bimonthly counts indicated temporary movements of several species beyond the unfenced park boundaries, especially duri ng very wet years and that few wildebeest entered the park during th e dry season following exceptionally we t conditions in 1998. Wildebeest were especially vulnerable to anthropogenic impacts in their wet se ason dispersal range on the plains. Deterioration in grassland conditions in the park following high ra infall plus lack of burning may have di scouraged these animals from using the park as a dry season refuge. Our findings emphasise the interdependency between the park and the plains for seasonal wildlife movements, especially in exceptionally dry or wet ye ars. To effectively conserve these ungulates, we recommend implementation of the new land-use plan for the Athi-Kaputiei Plains by the c ounty government; expansion of the land leasing program for biodiversity payments ; collecting poacher’s snares; negotiation and enforcement of easements, allow- ing both wildlife and livestock to move through the Athi-Ka putiei Plains, providing incentive s for conservation to land- owners; and improving grassland conditions within the park through controlled burning so that more wildlife can gain protection there.