The results from the phytosociological analysis indicate the inselberg vegetation has four major communities, 11 communities, 13 sub-communities and 18 variants (Online Appendix 1). Overlap exists with sub-communities and variants. The name designated for each cluster is for the highest order unit, whilst ignoring those of lower rank (Online Appendix 1). The names are:
Major community 2, Crassula peploides – Polevansia rigida, Sheet Rock Grass and Forblands
Community 2.1, Scirpus ficinioides – Pentaschistis exserta, Grassland
Sub-community 2.1.1, Crassula peploides – Rhodohypoxis rubella, Wet Grassland
Variant 2.1.1.1 Koeleria capensis
Variant 2.1.1.2 Eucomis schijffii
Variant 2.1.1.3 Pentaschistis airoides
Sub-community 2.1.2, Scirpus ficinioides – Styppeiochloa gynoglossa, Alpine Grassland
Variant 2.1.2.1 Glumicalyx montanus
Variant 2.1.2.2 Helichrysum pagophilum
Sub-community 2.1.3, Erica dominans – Polevansia rigida, Alpine Grassland
Variant 2.1.3.1 Clutia nana
Variant 2.1.3.2 Festuca caprina
Variant 2.1.3.3 Styppeiochloa gynoglossa
Community 2.2, Ficinia cinnamomea – Felicia linearis, Heathland
Sub-community 2.2.1, Clutia nana – Hesperantha baurii, Forbland
Sub-community 2.2.2, Erica algida – Erica glaphyra, Heathland
Major community 4, Merxmuellera drakensbergensis – Helichrysum trilineatum, High-Altitude Alpine Fynbos Grassland
Community 4.1, Scirpus falsus – Anthospermum basuticum, Fynbos Shrubland
Sub-community 4.1.1, Macowania glandulosa – Disa crassicornis, Fynbos Shrubland
Variant 4.1.1.1 Merxmuellera disticha
Variant 4.1.1.2 Erica reenensis
Sub-community 4.1.2, Scirpus falsus – Anthospermum basuticum, Fynbos Shrubland
Community 4.2, Erica glaphyra – Helichrysum trilineatum, Alpine Grassland
Sub-community 4.2.1, Schoenoxiphium filiforme – Euryops montanus, Fynbos
Variant 4.2.1.1 Helichrysum albo-brunneum
Variant 4.2.1.2 Erica dissimulans
Variant 4.2.1.3 Cliffortia filicauloides
Sub-community 4.2.2, Erica dominans – Schoenoxiphium schweickerdtii, Heathland
Variant 4.2.2.1 Passerina drakensbergensis
Variant 4.2.2.2 Erica maesta
Variant 4.2.2.3 Dimorphotheca jucunda
Variant 4.2.2.4 Moraea alticola
Variant 4.2.2.5 Merxmuellera stricta
Community 4.3, Merxmuellera drakensbergensis – Schoenoxiphium schweickerdtii, Alpine Grassland
Sub-community 4.3.1, Helichrysum montanum – Sebaea spathulata, Forbland
Sub-community 4.3.2, Glumicalyx goseloides – Oxalis obliquifolia, Wet Meadow
Major community 1 only has a single diagnostic species, Rhodohypoxis rubella, with constancy of 75 and no dominant species. There are no other species which occur with >± 50% dominance or constancy (Online Appendix 1), thus a single species is used to name it.
The wetland vegetation consists of 11 relevés with nine species of which only Pentaschistis airoides occurs with any significant presence. It constitutes largely aquatic forbs and contributes 10% to the total vegetation surveyed. The high-altitude bogs, mires and peatlands described by Killick (1963, 1978a, 1978b, 1990), Hillard and Burtt (1987) and Hill (1996) and found on the escarpment top in Lesotho and the Mont-aux-Source/Tugela Falls area show floristic affinities with major community 1, Rhodohypoxis rubella (wetland) and to a lesser extent major community 2, Scirpus ficinioides – Polevansia rigida (alpine grassland). Aquatic taxa include Aponogeton, Crassula, Limosella and Rhodohypoxis on wet gravel plains and seeps.
Major community 2, Crassula peploides – Polevansia ridida (sheet rock grass and forblands), occurring on gravel seeps, has limited cover/abundance of most species and, after major community 1, is lowest in species richness and contributes 39% of the total relevés. The shallow soils, gravel plains and sheet rock would appear to be the limiting factor responsible for the low growth form and limited species numbers and presence. The scattered, open nature vegetation is problematic in naming major community 2. Polevansia rigida was selected as the primary name as it had the highest cover/abundance and constancy out of all other species for all 28 relevés (Online Appendix 1). Monocots comprise 61% of the diagnostic, constant and dominant species for major community 2, constituted by 31 species, 18 are monocots and 13 are dicots of which 3 are Crassulaceae. No carnivorous plants were found, unlike at Platberg, where Urticaceae and Droseraceae species formed distinct communities (Brand, Du Preez & Brown 2013). Carnivorous plants from both these families are reported to be significant components of shallow soil and ephemeral flush vegetation communities occurring on inselbergs in the Ivory Coast (Porembski & Barthlott 1997).
Major community 3, Pentaschistis exserta – Merxmuellera stricta (high-altitude alpine grassland), is dominated by and contains the majority of the C3 high-altitude, medium to small bunch grasses, Pentaschistis airoides, Pentaschistis basutorum, Festuca caprina and Merxmuellera stricta, which was chosen as the second syntaxonomic name (Online Appendix 1) as it has a 54% presence and cover/abundance, greater than the other five co-dominant species. The fynbos shrubs, best represented in community 3.3, include Cliffortia nitidula, Erica dominans, Macowania sororis, Passerina montana with the forbs Glumicalyx goseloides, Hebenstretia dura, Helichrysum album, Helichrysum sutherlandii, Helichrysum pagophilum and Helichrysum trilineatum (26%, cover/abundance) the only non-fynbos shrub. Geophytes include Eucomis schijffii, Gladiolus longicollis, and Ornithogalum sephtonii; all high-altitude DAC-endemic taxa. Of significance is that no Themeda triandra was found whilst both Festuca costata and Festuca caprina have very limited occurrence, unlike the Themeda-Festuca alpine veld of Acocks (1988). Additionally, Chrysocoma ciliate, described as common and with increased occurrence on overgrazed areas (Acocks 1988), was found in only one relevé with ‘+’ cover.
Major community 4, Merxmuellera drakensbergensis – Helichrysum trilineatum (high-altitude alpine fynbos grassland) represents the vegetation common to and found on all inselbergs. The dominant plants are alpine C3 grasses combined with Helichrysum trilineatum, fynbos shrubs and the genus Erica which form heathlands. Major community 4 has species and physiognomic affinities with the uKhahlamba Basalt Grassland and the Drakensberg Afroalpine Heathland (Mucina & Rutherford 2006). This cluster shares affinities with the lower-altitude Drakensberg-Amathole Afromontane Fynbos and the Lesotho Highlands Basalt Grassland (Mucina & Rutherford 2006). Common dominant and prominent shrubs include the fynbos genera Cliffortia, Erica, Euryops, Helichrysum and Macowania. The altitude precludes any trees or shrubs over 2.5 m tall, which do occur at lower, more protected altitudes. This major community contains most of the endemic forbs and geophytes, which constitute numerous rare, threatened and endangered taxa. Sub-communities 4.1.1 and 4.2.1 are good representatives of this, as all three Orchidaceae, Disa crassicornis, Dracomonticola virginea and Satyrium longicauda Lindl. var. jacottetianum, occur in them. Other endemic geophytes include Albuca humilis, Eucomis schijffii, Moraea alpine, Moraea alticola, Ornithogalum sephtonii and Rhodohypoxis rubella.
All inselberg vegetation has a grass component, including most of the wetlands, rocky outcrops and gravel seeps, with 89 out of 103 relevés complying. Alpine grasses provide 98% cover/abundance and consistency throughout all four major communities, with the high-altitude vegetation dominated by C3 grasses. There are two C4 grasses: Polevansia rigida, 14 of the 28 relevés forming community 2.1, and Eragrostis caesia, occurring in 4 relevés and with low cover/abundance. Although there were only 27 graminoids (grasses and sedges) compared with 162 non-graminoid shrubs and forbs, they contribute 81% (82 plots) of the total cover of the 103 plots. The sedge Scirpus ficinioides was especially dominant in sub-communities 2.1.1 and 2.1.2, with the grass Pentaschistis exserta providing 93.5% presence in major community 3 (14 of 15 relevés). Dominant graminoid species varied from community to community, with Merxmuellera drakensbergensis, Scirpus falsus and Schoenoxiphium schweickerdtii the most dominant (major community 4, 98% average cover). The monotypic alpine grass Styppeiochloa gynoglossa, endemic to South Africa, is dominant in community 2.2 and sub-community 4.1.2. Community 2.2 is defined by Ficinia cinnamomea, and Ficinia gracilis is dominant for variants 4.2.2.2 and 4.2.2.3 (80% cover). Festuca costata occurs in only nine plots with only a ‘+’ value. This is contrary to its reported occurrence and dominance used by Acocks (1988) to define the Themeda-Festuca alpine veld and which Mucina and Rutherford (2006) state defines the core of the DAC of Endemism. Of the 16 grass species (from nine genera), all are C3 except for Polevansia rigida, the only mat-forming, stoloniferous, rhizomatous grass, and Eragrostis caesia. The presence of Eragrostis caesia, which is a short to medium height (450 mm – 600 mm) densely tufted grass, unlike other Eragrostis species, may be explained by the same temperature protection – thermal microclimate created by dense or large tussock growth form of Merxmuellera drakensbergensis and Merxmuellera stricta (Körner 2003; Tieszen et al. 1979). This same physiognomic, large-tussock grass is exhibited by another C4 grass, Andropogon amethystinus, which forms large tussocks, found on the Aberdares and Mt. Kenya above 3000 m, and which has the same growth characteristic as Eragrostis caesia (Tieszen et al. 1979).
Plant physiological adaptation to alpine conditions can be seen in the large tufted grasses Merxmuellera, Pentaschistis, Festuca, Eragrostis caesia, Styppeiochloa gynoglossa; the filiform leaves of the sedges and forbs Cyprus schlechteri, Ficinia cinnamomea, Scirpus ficinioides, Schoenoxiphium filiforme, Schoenoxiphium schweickerdtii; the forbs Felicia linearis and Thesium pallidum; both tall and low cushion-shaped shrubs Helichrysum trilineatum, Cliffortia, Erica, Macowania sororis, Passerina; low tufts Anthospermum basuticum and Muraltia. It is also displayed by the pubescence of many forbs, Arctotis arctotoides, Berkheya rhapontica, Craterocapsa tarsodes, Dimorphotheca jucunda, Gazania krebsiana, Geranium multisectum, Glumicalyx goseloides, Helichrysum album, Helichrysum sutherlandii, Helichrysum pagophilum, and Senecio othonniflorus. Succulents and geophytes, plants with below-ground bulbs or corms, are two other adaptations to alpine conditions. Succulent plants found are Delosperma sphalmanthoides and Othonna burttii and geophytes include Albuca polyphylla, Disa crassicornis, Dracomonticola virginea, Eucomis schijffii, Hesperantha baurii, Ledebouria ovatifolia, Moraea alticola, both species of Rhodohypoxis and Sebaea spathulata Sebaea thodeana (Hedberg 1964; Körner 2003; Masao et al. 2013).
The high-altitude wetland community dominated by sedges and described by Hill (1996) has affinities with major communities 3 and 4. The common sedges are Scirpus ficinioides and Schoenoxiphium filiforme. Two dominant grasses of Hill's high-altitude wetland community are Merxmuellera drakensbergensis and Pentaschistis oreodoxa, not found in the inselberg wetlands, but components of major community 4. From Hill's (1996) description of the high-altitude wetland community, it shows more species and vegetation affinities with major community 4, the alpine grasslands, than with wetlands on the inselbergs.
Of all regions in the Drakensberg, the inselbergs may be regarded as showing no anthropogenic influence from grazing, ploughing or fire, which does occur but is lighting induced. There is limited human presence: climbers have built cairns on most of the peaks, there are log books on Sentinel and Cathkin Peak, a bovine skull – probably a cow placed as vulture food – and the metal top of a smoke grenade was found on Cathkin, and tourists visit Inner and Outer Horn via helicopter; however, human impact is negligible, unlike the heavily impacted, overgrazed, hoof-eroded adjacent escarpment in Lesotho.