Livestock Feeding Ecology and Resource Utilization in a Nomadic Pastoral Ecosystem

TLDR

The study aimed to characterize livestock trophic niche segregation and harvesting capacity across heterogeneous vegetation in this ecosystem. The authors quantified seasonal forage selection, diet diversity, and habitat use of Ngisonyoka Turkana livestock in arid north‑western Kenya through direct observation of free‑ranging herds. Cattle and camels were grazing specialists, goats, sheep, and donkeys generalists, and seasonal changes—especially dry periods—reduced diet diversity, increased habitat use variation, and heightened habitat segregation; collectively, livestock maintained a broad, opportunistic, temporally stable trophic niche through equitable use of all forage classes and mobility, which is vital for nomad survival and counteracts development strategies that limit species diversity or mobility.

Abstract

(1) Seasonal patterns of forage selection, diet diversity, and habitat use were quantified for livestock managed by the Ngisonyoka Turkana in arid north-western Kenya by direct observation of free-ranging herds. The objective was to characterize the trophic niche segregation of livestock and their potential harvesting capacity for the heterogeneous vegetation resources of this ecosystem. (2) Cattle and cam Js were grazing and browsing specialists, respectively, while goats, sheep, and donkeys, were' generalists for both herbaceous and non-herbaceous vegetation. (3) Diet and habitat use were greatly influenced by season. Relative to brief rainy periods of resource abundance, long dry intervals of resource scarcity were times of reduced diet diversities (forage-class basis) for most species and greatly increased variation in habitat use. Livestock generally exhibited the greatest diet similarity in dry periods but were most segregated in terms of feeding habitats during these times. (4) The livestock in aggregate provided a very broad, opportunistic, and temporally stable trophic niche that resulted from equitable use of all forage classes, and their mobility provided a means to exploit the entire region. These attributes are essential for the persistence of nomads in this harsh, unpredictable environment, and are inimical to development tactics that serve to reduce livestock species diversity or restrict mobility.