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Research on early human occupations in Africa is challenged with contextualizing artifacts with environmental landscape reconstructions. Understanding the landscape that humans inhabited is crucial for discerning how particular forms of technology (stone tools, grinding stones, ceramics) were used and how prehistoric people succeeded and failed in their modes of subsistence. This knowledge can teach us about how to develop sustainable alternatives that balance the needs of nature and humans alike.

Research along the Galana River in Tsavo National Park , Kenya is providing a useful data set through which multiple, long-term habitations of several sites from the Middle to Late Holocene are currently being analyzed. Early foraging occupations of the site of Kahinju (5960±480 years bp, 5000 ±400 years bp ) correlate to pluvial periods as recorded in δ¹⁸ O ice core records from Mount Kilimanjaro (Thompson et al. 2002) . These occupations also correspond to periods of generally low periodicity in the El Niño/La Niña cycle (Moy et al. 2002) . Wild game have been observed as being dispersed throughout the park during pluvial periods (Leuthold and Leuthold 1973) , which would have hindered hunting efforts in light of low densities of prey per km 2 of available hunting territory. In turn, the faunal assemblage from this time period reflects a high predation on endoaquatic game such as crocodiles, hippopotamus, vervet monkeys, snakes, mudfish, terrestrial and freshwater mollusks. Therefore, foragers in Tsavo utilized the resources of the river when wild resources on the open plains were difficult to obtain.

Later occupations that bear evidence of domesticated cattle (3,800 - 2,500 years bp ) correlate to generally arid periods with high periodicity in the El Niño/La Niña cycle. Faunal material analyzed from the site shows a more diverse subsistence base than during earlier foraging occupations. Wild ungulates and domesticated cattle comprise most of the assemblage and archaeological material is more abundant from this time period. During arid periods, wild animals tend to aggregate along the margins of the river (Leuthold and Leuthold 1973) , providing easy prey for opportunistic hunters. Furthermore, the unpredictability of the environment during times when there were rapid and profound shifts between El Niño and La Niña cycles made settlement along the Galana River very attractive. Cattle must drink water at least once per day if they are to produce milk. Riverine resources are predictable and would have buffered against the uncertainty of survival away from a permanent water source.

Luminescence is a unique tool for analyzing complex archaeological assemblages because non-organic bearing strata can be reliably dated in order to build a complete picture of site settlement and abandonment. Furthermore, environmental reconstructions such as river aggrading and degrading episodes can be understood in the context of human occupations regardless of preservation bias or groundwater reservoir contamination. The data from Tsavo is being used to argue that sustainable development of pastoral landscapes is possible in fluctuating natural environments. Based on this research, we argue for flexibility in regulations that restrict hunting and grazing in "pristine" national wildernesses such as Tsavo. Use of the landscape in a responsible manner will insure that natural resources will be available for future generations while meeting the needs of the current generation.

Occupations of Kahinju correlated with ENSO periodicity data (Moy et al. 2002) .

Occupations of Kahinju correlated with δ¹⁸ O proxy data from Mount Kilimanjaro (Thompson et al. 2002) .