Classification, description and environmental factors of montane wetland vegetation of the Maloti-Drakensberg region and the surrounding areas

Classification and description of wetland vegetation provides an understanding of the wetland vegetation-environment relationships, as well as their spatial variation and information for water resource management and biodiversity conservation. In this study, the montane palustrine wetland vegetation types of the Maloti-Drakensberg region and surrounding areas are discussed based on a phytosociological approach. The montane subset of the National Wetland Vegetation Database of South Africa was selected and supplemented with the new data collected from the Lesotho component of the Maloti-Drakensberg region. This montane subset was collected using the Braun-Blanquet method for vegetation and recommended methods for wetland environmental data. The new vegetation data from Lesotho were collected using the same methods used for the historical data. The combined data were then analysed mainly by means of clustering and ordination techniques. Forty-two wetland plant communities were obtained from the cluster analysis and these were summarised into sixteen community groups. These community groups are diverse in terms of species richness and also exhibit significant variation along the altitudinal gradient, mainly due to variations in environmental conditions that include temperature, parent material and the amount of precipitation, among other factors. The ordination revealed that the variation in the wetland vegetation is mainly explained by altitude, longitude, latitude, nitrogen content, soil depth, inundation depth and electrical conductivity, but slope, pH, sodium content, total organic carbon, soil texture and degree of wetness are also important. In terms of species composition, high altitude plant communities were distinctively different from those at low altitudes. Regarding distribution, montane wetland vegetation was found to be more concentrated in the Maloti-Drakensberg region than the rest of the region, although some community groups also occurred in the lowlands of Lesotho and all the provinces of South Africa. The diversity exhibited by these wetlands, coupled with their restricted distribution at high altitudes, capacity to support endemic species, their role in water resources and provision of other ecosystem services, point to the high conservation value associated with these ecosystems. (C) 2019 SAAB. Published by Elsevier B.V. All rights reserved.