Fragmentation and settlement pattern in Maasailand – implications for pastoral mobility, drought vulnerability, and wildlife conservation in an East African savanna

Abstract

Fragmentation through land privatization and sedentarization impacts the conservation and management of grazing systems around the world. In this study I examine how rangeland fragmentation and the loss of key resource areas impact the structure and function of the pastoral grazing system and the implications for large wild herbivore (wildlife) distribution and abundance. I used a land tenure and sedentarization gradient in the Greater Amboseli Ecosystem (GAE) of Kajiado District, Kenya to quantify the effects of fragmentation on patterns of pastoral settlement, livestock mobility and drought vulnerability at multiple spatial and temporal scales. I developed a new high resolution aerial counting technique to examine both broad and fine scale responses of wildlife to fragmentation and pastoral settlements, and the loss of key resource areas to agriculture and conservation. Fragmentation has led to a fundamental transformation of pastoral settlement and grazing patterns in the GAE. Formerly flexible settlement systems have been replaced with dispersed and clustered patterns of settlement in privatized and collectively managed areas respectively. Seasonal grazing patterns have moved from a wet to a dry season dispersal system as forage availability replaced water distribution as a fundamental constraint. Livestock in highly fragmented areas moved less under normal rainfall conditions, but appeared to move earlier, and farther than their less fragmented neighbors under drought conditions. Analyses of broad scale livestock movement over a two year period (1999 - 2000) revealed that livestock were not maximizing their access to green forage biomass as indicated by NDVI. Increasing pastoral land-use intensity reduced wildlife biomass and differentially altered wildlife distribution patterns in relation to pastoral settlements depending on body size and feeding strategy. Similarly, increasing agricultural development in key resource areas reduced wildlife biomass and altered distributions relative to permanent water. Protection increased wildlife biomass and provided an important refuge for certain species, but some species were locally absent due to habitat changes associated with elephant compression. This study illustrates the importance of fragmentation in altering patterns of pastoral production and exacerbating vulnerability to extreme climatic events, and highlights the cascading effects these changes may have for wildlife conservation inside and outside protected areas.