For millenia, Greater Amboseli ecosystem of Kenya has had a central role in subsistence pastoralism and wildlife conservation by providing vast biological resources for pastoralists and their livestock; and habitat for wildlife. Recently, with the creation of Amboseli National Park and rapid changes in land tenure systems, the human use of the ecosystem has intensified. This change has shaped a pastoral landscape composed of livestock grazing, wildlife conservation, rain-fed and riverine crop cultivation and permanent settlements. A study was undertaken to map land use over time, and document the causes and consequences of these changes for land cover, vegetation species diversity and distribution within the 3,112 km² of Amboseli ecosystem. Remote sensing, Geographic Information Systems and ground-based techniques were applied. Land-use and land-cover maps were produced with an accuracy of 85.7% and changes analysed for the years 1988 and 1998. During the ten-year period, changes in natural vegetation cover and cultivated fields were significant (p<0.05) with cultivated fields replacing 8% of natural vegetation. Cultivation increased along the mountain slopes, rivers and swamps — areas formerly used by pastoralists and wildlife for dry season grazing. Land-cover types changed significantly with bushed grassland and cultivated fields increasing by 10% and 8% respectively; while grassland and bush land decreased by 6% and 11% respectively. The overall result is a change in landscape structure with increasing patch diversity as number of patches increased from 157 in 1988 to 250 in 1998. Likewise ecosystem complexity declined with mean cover type area decreasing significantly (p<0.05) from 1,989 ha in 1988 to 1,247 ha in 1998. Mean cover type perimeter and dominance value both changed significantly (p<0.01) from 234 meters to 211 meters and 2.09 to 2.04 respectively. The emerging land-use and land-cover types can be attributed to changes in land tenure policies and pastoralists' socio-economic lifestyles. These on-going trends pose greater threat to survival of pastoralism and wildlife conservation within East African rangelands as pastoral lands and wildlife habitats continue to be fragmented and fenced off. The results of this study reveals the need for integrated research that would address policy issues, pastoral welfare, benefit sharing, resource accessibility and utilisation, and wildlife conservation so that landscape fragmentation and resource degradation can be managed.