Luke, H. 1952. A visit to Easter Island. Geographical Magazine 25:298-306.

Mann, D., J. Chase, J. Edwards, W. Beck, R. Reamer, and M. Ma.s.s. 2003. Prehistoric destruction of the primeval soils and vegetation of Rapa Nui (Isla de Pascua, Easter Island). In Easter Island- Scientific Exploration into the World's Environmental Problems in Microcosm, ed. J. Loret and J. T. Tancredi, 133-53Dordrecht: Kluwer Academic / New York: Plenum.

Mieth, A., and H.-R. Bork. 2005. History, origin and extent of soil erosion on Easter Island (Rapa Nui). Catena 63:244-60.

Olafsdottir, R., and H. J. Guamundsson. 2002. Holocene land degradation and climatic change in northeastern Iceland. Holocene 12:159-67.

Ponting, C. 1993. A Green History ofthe World: The Environment and the Collapse of Great Civilizations. New York: Penguin Books.

Sveinbjarnardottir, G. 1991. A study of farm abandonment in two regions of Iceland. In Environmental Change in Iceland, 161-77.

Williams, J. 1837. A Narrative ofMissionary Enterprises in the South Sea Islands. London: J. Snow.

Williams, M. 2003. Deforesting the Earth: From Prehistory to Global Crisis. Chicago: University of Chicago Press.

10. LIFE SPAN OF CIVILIZATIONS.

Berry, W. 2002. The whole horse. In The Fatal Harvest Reader: The Tragedy of IndustrialAgriculture, ed. A. Kimbrell, 39-48. Washington, DC: Island Press.

Ca.s.sman, K. G. 1999. Ecological intensification of cereal production systems: Yield potential, soil quality, and precision agriculture. Proceedings of the NationalAcademy of Sciences of the United States ofAmerica 96:5952-59.

Ca.s.sman, K. G., S. K. De Datta, D. C. Olk, J. Alcantara, M. Samson, J. Descal- sota, and M. Dizon. 1995. Yield decline and the nitrogen economy of longterm experiments on continuous, irrigated rice systems in the tropics. In Soil Management: Experimental Basis for Sustainability and Environmental Quality, ed. R. Lal and B. A. Stewart, 181-222. Boca Raton: Lewis Publishers.

Ehrlich, P. R., A. H. Ehrlich, and G. C. Daily. 1993. Food security, population and environment. Population and Development Review 19:1-32.

Engels, F. 1844. The myth of overpopulation. In Marx and Engels on Malthus, ed. R. L. Meek, trans. D. L. Meek and R. L. Meek, 57-63. London: Lawrence and Wishart, 1953.

Huston, M. 1993. Biological diversity, soils, and economics. Science 262:1676-80.

Kaiser, J. 2004. Wounding Earth's fragile skin. Science 304:1616-18.

Larson, W. E., F. J Pierce, and R. H. Dowdy. 1983. The threat of soil erosion to long-term crop production. Science 219:458-65.

Pimentel, D., J. Allen, A. Beers, L. Guinand, R. Linder, P. McLaughlin, B. Meer, D. Musonda, D. Perdue, S. Poisson, S. Siebert, K. Stoner, R. Salazar, and A. Hawkins. 1987. World agriculture and soil erosion. BioScience 37:277-83.

Pimentel, D., C. Harvey, P. Resosudarmo, K. Sinclair, D. Kurz, M. McNair, S. Crist, L. Shpritz, L. Fitton, R. Saffouri, and R. Blair. 1995. Environmental and economic costs of soil erosion and conservation benefits. Science 267: 1117-23.

Saunders, I., and A. Young. 1983. Rates of surface processes on slopes, slope retreat and denudation. Earth Surface Processes and Landforms 8:473-501.

Smith, A. 1776. Inquiry into the Nature and Causes of the Wealth ofNations. London: W. Strahan and T. Cadell.

Tilman, D. 1999. Global environmental impacts of agricultural expansion: The need for sustainable and efficient practices. Proceedings of the National Academy ofSciences of the United States ofAmerica 96:5995-6000.

Tilman, D., J. Fargione, B. Wolff, C. D'Antonio, A. Dobson, R. Howarth, D. Schindler, W. H. Schlesinger, D. Simberloff, and D. Swackhamer. 2001. Forecasting agriculturally driven global environmental change. Science 292: 281-284.

United Nations Development Programme. 1996. Urban Agriculture: Food, Jobs and Sustainable Cities. New York.

Vitousek, P. M., H. A. Mooney, J. Lubchenco, and J. M. Melillo. 1997. Human domination of Earth's ecosystems. Science 277:494-99.

Wilkinson, B. H. 2005. Humans as geologic agents: A deep-time perspective. Geology 33:161-64-