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Science 8 November 1985:
Vol. 230. no. 4726, pp. 619 - 625
DOI: 10.1126/science.230.4726.619
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Articles

Energy Extraction and Use in a Nomadic Pastoral Ecosystem

M. B. Coughenour 1, J. E. Ellis 2, D. M. Swift 1, D. L. Coppock 3, K. Galvin 4, J. T. McCabe 5, and T. C. Hart 6

1 Research associate, Colorado State University, Fort Collins 80523.
2 Senior research scientist, Colorado State University, Fort Collins 80523.
3 International Livestock Center for Africa, Post Office Box 5689, Addis Ababa, Ethiopia
4 Postdoctoral research associate at NREL.
5 Assistant professor in the Department of Anthropology, University of Georgia, Athens 30602.
6 Research associate at NREL.

An analysis of annual energy flows in an arid tropical ecosystem inhabited by nomadic pastoralists provides insight into a subsistence life-style that has persisted in droughted environments for hundreds to thousands of years. Although a large fraction of the total energy consumed by the Ngisonyoka of Kenya followed a single pathway from plant to animal to human, they also harvested solar energy from a relatively diverse assemblage of energy flow channels. Energy utilization and conversion efficiencies were generally low, as the system is maintenance-rather than production-oriented. Energy flow to maintenance must be relatively high to support biotic responses that enable tolerance of abiotic variability and to stabilize energy flow under the stress of severe droughts. Energy utilization by the Ngisonyoka is therefore consistent with ecological patterns that promote rather than diminish ecological stability under stress.


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