The magnitude and geographic reach of human impact on Earth?s biosphere has increased rapidly over the last century, in particular in East Africa where rates of population growth and the intensification of agriculture are among the highest in the world, and where developing economies strongly depend on water and other goods and services provided by natural ecosystems. Economic development with conservation of biodiversity and ecosystem functioning requires spatially and temporally explicit knowledge of the timing and relative magnitude of (pre-)historical and modern human impact on terrestrial and aquatic ecosystems to 1) evaluate the current health of these ecosystems and their resilience to anthropogenic disturbance, 2) model the range of their possible responses to future climatic, demographic and economic change, and from these 3) develop locally optimal strategies for land and water-resource management.