Patterns of change in reed cover and distribution in a seasonal riverine wetland in South Africa
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Phragmites mauritianus is the dominant herbaceous species colonizing riverine habitats in the Kruger National Park, South Africa. These perennial systems are characterized by high annual and seasonal flow variability and a complex mosaic of patches of reeds, sand, water, rock and other vegetation. Patterns of increase and decrease in reed cover in the Letaba River were determined from aerial photographs covering a 54-year period. An initial period of reed expansion (1942–1965) was followed by a period of reed loss (1965–1977) and subsequent gradual re-establishment (1977–1996). A spatially explicit analysis of changes in reed distribution over an 8-year period (1988–1996) showed that patches of reed vegetation are, in the short term, highly dynamic elements within the river landscape. Analyzing short-term, small-scale change provides information which is not obtainable from long-term, large-scale studies. We propose that causes of reed expansion or decline cannot be determined without an understanding of both long- and short-term patterns of change.
KeywordsGeographical Information System Kruger National Park Letaba River Phragmites mauritianus
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