**5.2 Fynbos Biome affinities**

Fynbos on Platberg occurs in 13 different communities, which can be grouped into two communities (Brand 2008). The sclerophyllous vegetation is characterised by *Passerina montana*, a fynbos taxa endemic to the Cape (Figure 6). These fynbos communities have a species richness varying between 14 – 54 species per 30 m², with an average of 28.34 species per 30 m². This is lower compared with the grassland vegetation, which has 11 – 54 per 30 m² with an average of 32 per 30 m², which gives a moderate species diversity index. A minimum 16 fynbos genera comprising 22 species occur on Platberg. The fynbos is located in two distinct habitats: the lower altitude zone at 2000 m growing on the mineral poor soils of the Cave Sandstone of the Clarens Formation, and the higher altitude zone at 2200 m on the rocky, basaltic, mineral rich rim of the plateau just below the exposed summit grassland (Brand et al., 2008).

Fynbos and the Gm 24 Northern Escarpment Afromontane Fynbos (Mucina & Rutherford 2006). This afromontane fynbos community is found on most of inselbergs including the Floristically, and structurally, the *Passerina montana* fynbos-like shrubland elements found on Platberg conform with the Gd 6 Drakensberg-Amathole Afromontane Korannaberg 200km west, and a similar altitude of 2000-2200 m in the Drakensberg. For Mucina & Rutherford (2006) it is structurally and floristically different from the other Afromontane fynbos species rich community found at higher altitudes and embedded in the Gd 8 Lesotho Highveld Basalt Grassland.

Biogeography of Platberg, Eastern Free State, South Africa:

**5.4 Grassland Biome affinities** 

(Table 3).

Tanzania: Serengeti Serengeti

 Uttar Pradesh Uttar Pradesh

Woodlands (modified from Retallack 2001)

Bredenkamp 1991; Du Preez et al., 1991).

India:

U.S.A.: Iowa Illinois

& Rutherford 2006).

Links with Afromontane Regions and South African Biomes 123

Grasses, the family Poaceae, is the single most important plant family for humanity (Gibbs-Russell 1991). It is distributed over all seven continents and is the fifth largest plant family on earth and the second largest family for the DAC. Globally, Poaceae comprise some 770 genera and 9 700 species (Gibbs-Russell 1991). Southern Africa there are approximately 194 genera and 967 species of which 329 are endemic (Carbutt & Edwards 2004, 2006). For the Drakensberg Alpine Centre there are 86 genera and 267 species, of which 22 endemic or near-endemic genera comprising 39 endemic or near-endemic species (Carbutt & Edwards 2004, 2006). Grasses, particularly C4 pathway users, are better than plant families in stripping and utilising CO2 from the atmosphere. Grasses store the Carbon below ground in roots and soils (Retallack 2001), and with the Savanna Biome are enormous sinks for Carbon

**Country/Region Vegetation Mean C (kg m -²)** 

Table 3. Mean Carbon (C) content in soils under Modern Grasslands and adjacent

Platberg and the DAC are within the Grassland Biome, and as such are dominated by grasses. Grassland is a complex mix of graminoids, forbs and geophytes (Mucina & Rutherford 2006). Geophytes are abundant on Platberg, with Amaryllidaceae, Asphodelaceae, Hyacinthaceae, Hypoxidaceae and Iridaceae growing throughout the grassland, fynbos, woody/shrub and wetland communities. These geophyte families are also important fynbos components (Goldblatt & Manning 2000) and are prominent members in the Succulent and Nama Karoo Biomes (Van Wyk & Smith 2001; Pond et al., 2002; Mucina

On a regional scale, strong floristic affinities exist between Platberg and the Drakensberg grasslands to the south (Bester 1998), which includes Qwa-Qwa (Moffett 2001), the Golden Gate Highlands National Park (Roberts 1969; Kay et al., 1993), the central Cathedral Peak area, and southern Drakensberg (Killick 1963, 1978a, 1978b; Van Zinderen Bakker 1973; Hillard & Burtt 1987), the Stormberg and Eastern Cape Drakensberg (Hill 1996; Carbutt & Edwards 2004), as well as Korannaberg to the western interior of the Free State (Du Preez &

The development of high biodiversity and species richness of Poaceae across the Grassland Biome has a number of explanations; these include a combination of weather (Mean Frost Days, and minimum daily temperature) and moisture availability (Mutke et al., 2001), soils, and the effects of fire and grazing (Seabloom & Richards 2003). Moisture availability is an

Tall grassland 51.4 Dry woodland 12.8

Terai grassland 23.5 Monsoon forest 3.9

Tall prairie 14.9 Oak forest 8.2

The Afromontane fynbos genera found on Platberg are Passerina, Cliffortia, Erica, Euryops, Helichrysum, Macowania, Metalasia, Muraltia, Pentaschistis, Ischyrolepis, Schoenoxiphium and Watsonia, all of which are endemic taxa typically found in the Cape Floristic Region (Goldblatt & Manning 2000).

The grass-like genus *Restio* is a major component of the Cape flora not found on Platberg or the broader Drakensberg, however, *Ischyrolepis schoenoides,* is found on Platberg and other inselbergs in the Free State (Du Preez & Bredenkamp 1991; Malan 1998) and could be regarded as an ecological equivalent for *Restio*, as its growth form and habitat is similar. Phylogenetically, these two genera are closely related (Haaksma & Linder 2000) and Germishuizen et al., (2006) lists *Restio schoenoides*, *Kunth* (1) as a synonym for *Ischyrolepis schoenoides* (Kunth) H.P. Linder (Brand et al. 2010). The remnants of fynbos vegetation on Platberg may be relicts from cooler periods when more extensive fynbos migrated over lower altitudes starting during the Late Pleistocene and evident up to the last Glacial Maximum (Scott et al., 1997).

Fig. 6. Fynbos *Passerina montana* shrub community on Clarens Sandstone on Platberg.

Pollen taken from sites at Clarens, a town in the semi-arid interior of the Free State, 200km west of Platberg, and the Rose Cave site, near Ladybrand, 500km to the west of Platberg, located at the extreme western footslopes of the DAC, show a similar pattern for fynbos genera *Protea* and *Cliffortia* which were more abundant and are typical of upland vegetation.
