Skip to main content Accessibility help
  • Print publication year: 2007
  • Online publication date: September 2009

5 - Fertile and unstable habitats



Not all disturbances cause a loss of fertility. Disturbances typically include events that cause a loss of biomass (plant and animal tissues, or merely some organic matter). However, disturbances can also involve the displacement of biomass across the landscape. When biomass floats downstream, the areas where that biomass is deposited can become more fertile than they were before the disturbance. Ocean currents, tides and storm surges, and the seasonal turnover of lake waters also redistribute biomass and nutrients. Many civilizations have depended on such redistribution of nutrients. River floodplains have supported mighty cultures in Egypt along the Nile and in western Asia along the Tigris and Euphrates and still periodically fertilize many agricultural hotspots with organic and mineral-rich sediments. Coastal cultures have long depended on the bountiful products of cold, upwelling ocean currents that bring nutrient-rich waters to coastlines such as Peru and Norway.

This chapter explores how humans interact with fertile, unstable habitats after sudden or chronic disasters. These habitats include unstable slopes that result in landslides, river floodplains, lakeshores and estuaries. Landslides may be hard to farm and build on, but the burgeoning human population and increasingly sophisticated building technology have led to intensive human activities, both urban and agricultural, in these habitats. It is appreciated that living on a floodplain carries dangers, but floodplains are among the most fertile agricultural sites. Thus, while humans would prefer to live on stable sites that do not flood, they often rely on floods to deposit nutrients on their fields.

Larsen, M. C. and Simon, A. (1993). A rainfall intensity-duration threshold for landslides in a humid–tropical environment, Puerto Rico. Geografiska Annaler, 75A, 13–23.
Walker, L. R. and Moral, R. (2003). Primary Succession and Ecosystem Rehabilitation. Cambridge: Cambridge University Press.
Walker, L. R., Zarin, D. J., Fetcher, N., Myster, R. W. and Johnson, A. H. (1996). Ecosystem development and plant succession on landslides in the Caribbean. Biotropica, 28, 566–76.
Walker, L. R. and Willig, M. R. (1999). An introduction to terrestrial disturbances. In Ecosystems of Disturbed Ground, Ecosystems of the World 16, ed. Walker, L. R.. Amsterdam: Elsevier, pp. 1–16.
Ball, P. (2000). Life's Matrix: a Biography of Water. New York: Farrar, Straus and Giroux.
Hassan, F. A. (2005). A river runs through Egypt: Nile floods and civilization. Geotimes, 4, 22–5.
Wohl, E. (2004). Disconnected Rivers: Linking Rivers to Landscapes. New Haven: Yale University Press.
Ferguson, R. (2003). The Devil and the Disappearing Sea: A True Story About the Aral Sea Catastrophe. Vancouver: Rain Coast Books.
Hogarth, P. J. (2000). Biology of Mangroves. Oxford: Oxford University Press.
McKee, K. L., and Baldwin, A. H. (1999). Disturbance regimes in North American wetlands. In Ecosystems of Disturbed Ground, Ecosystems of the World16, ed. Walker, L. R.. Amsterdam: Elsevier, pp. 331–63.
United Nations (2006). In the Front Line: Shoreline Protection and Other Ecosystem Services from Mangroves and Corals. New York : United Nations Publishers.
Dyer, K. R. (1998). Estuaries: A Physiographic Introduction. New York: John Wiley & Sons.
Haslett, S. K. (2001). Coastal Systems. New York: Routledge.
Packham, J. R. and Willis, A. J. (2001) Ecology of Dunes, Salt Marsh and Shingle. London: Chapman and Hall.