The sclerophyllous wetlands on quartzite substrates in South Africa: Floristic description, classification and explanatory environmental factors

Abstract

A description of wetland habitats on nutrient-poor sandstone and quartzite substrates across South Africa is given. Most of these are situated in the Fynbos Biome and are dominated by sclerophyllous shrubs but there are some sedge-dominated vegetation types as well as geographical outliers found in Pondoland, the Kamiesberg, the Mpumalanga escarpment, the Soutpansberg and the Waterberg. A subset from a national survey of wetland vegetation was selected for analysis in terms of classification and ordination. This resulted in a classification of 27 communities which are summarized in eight community groups. The variation in the dataset can be largely differentiated by means of altitude and cations and the associated ordination separates a small number of plots belonging to communities that are also distributed outside of the Fynbos Biome from the rest of the dataset. Within the Fynbos Biome, there are different wetland vegetation types found on steep slopes, with shallow soils and a high sand content versus the valley bottoms with deeper soils and a higher silt and clay content. There are also small differences in the nutrient status of different communities. This research showed that wetland plant communities in nutrient-poor communities have a distinct species composition. Species originate from a diverse range of functional types and phylogenetic groups compared to the typical wetland vegetation found in nutrient-rich grassy habitats in the rest of the continent.