THE INFLUENCE OF FLOODING REGIMES ON FOREST DISTRIBUTION AND COMPOSITION IN THE TANA RIVER FLOODPLAIN, KENYA

The Tana River floodplain supports mainly evergreen forest in an otherwise semi-arid area. Floodplain forest growth can only be sustained at or above elevations which receive floods of a critical maximum frequency and duration. Tolerance to flooding thus seems to be a major determinant of forest distribution. A series of dams have been constructed in the Tana headwaters. Probable changes to the floodplain forest resulting from a new hydrological regime are discussed. Low regeneration levels in the Tana floodplain forest may reflect dependence on periodic favourable hydrological conditions for regeneration. While tolerance to maximum flood levels is important in all floodplain forests, floodplain forests in semi-arid areas also depend on minimum flooding frequencies and durations. -from Author