East African savannas are persistent socio-ecological systems undergoing unprecedented change. This dissertation focuses on the emerging agro-pastoral system of Maasai herders in the savanna lands adjacent to Tanzania’s Tarangire National Park. As pastoralists adopt cultivation, the relationship between humans and the land is changed. The new dynamics threaten the resilience of savanna systems. I examine three aspects of the human ecology of Maasai subsistence: changes in territory and political ecology, changes to the local common property system resulting from territorial compression, and how Maasai are responding to the production constraints of cultivation. I employed ethnography, social surveys, soil surveys and livestock demography to take a political ecology approach to investigating human-environment relations.

Maasai territory is being fragmented by forces from within and without Maasai society. Poverty is increasing, due to market integration, high cattle mortality and population growth. Despite this, the adoption of cultivation cannot be explained by poverty alone. Poverty interacts with land tenure insecurity and with environmental stochasticity to create conditions conducive to the adoption of cultivation. Subdivision fragments the pastures which support pastoralism, reducing mobility and flexibility critical to dryland ecosystems. A village zoning plan has led to the emergence of a new common property regime that appears sufficient for current grazing and cultivation needs yet the historical pattern of land allocation means some villagers have greater access to protected pastures and water than others. Rich soils from abandoned kraals are also unequally distributed across the landscape. Pastoralists must negotiate limited cultivation experience, wildlife raids and labor shortages to integrate pastoral and agricultural production.

Several trends suggest negative repercussions for future resilience of the socio-ecological system. Unequal resource distribution among land allocations, the history of interactions between stakeholder groups, and land use patterns that inadvertently concentrate resources among a few households are decreasing the flexibility demanded by semi-arid systems. To reduce the negative effects of cultivation, efforts should focus on improving yields on small plots, supporting livestock husbandry and integrating local residents and wildlife interests to build a resilient future.