PLANT-COMMUNITIES AND SPECIES RICHNESS OF THE AGROSTIS LACHNANTHA-ERAGROSTIS PLANA WETLANDS OF NORTHERN KWAZULU-NATAL

The wetlands described in this article include rivers, streams, vlei a reas and pans occurring within the grasslands of northern KwaZulu-Nata l. The vegetation of many of the wetlands, in particular high-lying vl ei areas, is in danger of being irreversibly changed due to desiccatio n of the areas caused by the encroachment of exotic plantations into t he high-lying grasslands. The objective of this study was to classify and describe the Agrostis lachnantha-Eragrostis plana major vegetation type associated with the wetlands. The TWINSPAN classification and su bsequent refinement by Braun-Blanquet procedures resulted in the ident ification of 16 plant communities (also referred to as vegetation unit s), which were then related to environmental factors using the ordinat ion algorithm DECORANA. Five distinct groups were distinguished, the d istribution of which was primarily explained by axis 1. Species richne ss was calculated for each plant community from the phytosociological data. In addition to this parameter, species rarity and naturalness of communities were also considered in an attempt to estimate the conser vation value of specific sites. Although being relatively species poor , the vlei areas and pans are of particular conservation importance du e to the restricted occurrence of certain species and the high degree of naturalness. However, no rare species were encountered.