A classification and description of the shrubland vegetation on Platberg, Eastern Free State, South Africa

Abstract

The natural environment is constantly under threat from human-related activities. Platberg, overlooking the town of Harrismith in the Free State, is an inselberg that presents a refuge for indigenous plants and animals. The natural vegetation of the area is threatened by various farming and grazing practices, as well as by commercial development. In order to obtain baseline data and to obtain an improved understanding of the long-term ecological processes, the vegetation of Platberg was investigated to establish Afroalpine floristic links to the Drakensberg, as well as for the management of natural resources. From a Two-Way Indicator-Species Analysis (TWINSPAN) classification, refined by Braun–Blanquet methods, four major plant communities were identified, which were subdivided into fynbos, wetland, woody/shrub and grassland. A classification and description of the shrubland is presented in this article. The analysis showed the shrubland divided into 20 different plant communities, which are grouped into eight major communities, 13 sub-communities and eight variants. A total of 450 species was recorded from 109 relevés. A total of 24 endemic, or near-endemic, and Red Data species belonging to the Drakensberg Alpine Centre (DAC) was collected, with 22 alien (introduced) species also being recorded. Numerous floristic links with the DAC, the Cape Floristic Region and the Grassland Bioregions to the north and west were found.<p><strong>Conservation implications:</strong> The floristic composition and community analysis proves Platberg to be an important centre for plant diversity, with high species richness, a variety of habitats, and complex ecosystems. This description of the woodland communities can be used to assist with the setting of criteria for the management and protection of inselbergs in the province.</p><p><strong>How to cite this article:</strong> Brand, R.F., Du Preez, P.J. & Brown, L.R., 2009, ‘A classification and description of the shrubland vegetation on Platberg, Eastern Free State, South Africa’, <em>Koedoe</em> 51(1), Art. #696, 11 pages. DOI: 10.4102/koedoe.v51i1.696</p&gt

Biogeography of Platberg, Eastern Free State, South Africa: Links with Afromontane Regions and South African Biomes

“…Platberg on the cool southern and eastern sides in particular, provide in current times, a similar habitat and climatic conditions reminiscent of both Holocene and Pleistocene with the grassland on the plateau a mix of upland C 3 grasses form cooler times, mixed with C 4 grasses from corresponding warmer times (Scott & Vogel 2000). On Platberg, the predominance of C 4 grasses indicates that it falls within the core of the Grassland Biome, with a species composition similar to that dominated by C 4 grasses from the supertribe Andropogonodae which includes (Brand et al, 2009). Shading out of competition and the dense rhizomatous, root system inhibits growth of other species.…”

“…This may offer a partial explanation for the high numbers of hybrids recorded, as well as the speciation and high numbers of endemics or near-endemics observed within the DAC and by extension, Platberg. Hybrids and rare species do not contribute to community patterns (beta-diversity), but are important for maintenance of biological diversity (Mutke et al 2001;Cowling & Lombard 2002 (Brand et al, 2009). Limited empirical research has been done to establish the connection between bird/plant community associations and is a subject for future investigation.…”

“…The analysis of the plant families on Platberg using C 3 , C 4 and Crassulacean Acid Metabolism (CAM) are from Brand et al, (2010). The phytosociological analysis for Platberg found 39 distinct plant communities (Brand et al, 2008(Brand et al, , 2009(Brand et al, , 2010 all of which contain a combination of Asteraceae Poaceae, and Cyperaceae. Only 7 plant communities are dominated by woody/shrubs and exclusively use the C 3 pathway.…”

“…(Scott et al, 2003). Today they are fragmented and are found as refugia in inselbergs (Brand et al, 2009) …”