Impact of Land Subdivision and Sedentarization on Wildlife in Kenya’s Southern Rangelands

Abstract

Subdivision and sedentarization of pastoral communities is accelerating rapidly across the African rangelands, posing a severe
threat to wildlife populations, but few studies have looked quantitatively at the ecological impact of sedentarization. Here we
look at the impact of sedentarization on wildlife by comparing ecologically matched subdivided and unsubdivided Maasai
pastoral lands (ranches) in semiarid southern Kenya. We found no significant difference in livestock densities on the two ranches
but there was a significantly higher wildlife density on the unsubdivided ranch, in both dry and wet seasons. Nonetheless, the
unsubdivided ranch still had a higher percentage of grass biomass and ground cover and lower grazing pressure than the
subdivided ranch. Distribution of homesteads (bomas) was mostly random on the subdivided ranch, with little area unaffected
by human settlement. On the contrary, the unsubdivided ranch had a highly clumped boma distribution pattern, resulting in
much of the land being relatively far from permanent human settlement. We show that the regular distribution and permanence
of settlements following subdivision and sedentarization greatly reduces wildlife populations both through direct displacement
and a reduction of forage. Relative to mobile pastoralism on open rangelands, sedentarization leads to reduced seasonal
movements of livestock, lowered grass biomass, and slower grass recovery after very dry periods. This study points to the need
to maintain mobile, large-scale herd movements to avoid the heavy impact on grasslands associated with sedentarization of
pastoral settlement and herds.

Key Words: grass biomass, land tenure, livestock, Maasai, pastoralism, wildlife conservation