Golden Gate Highlands National Park (hereafter GGHNP) (Figure 1) is in the vicinity of Clarens in the eastern Free State (28°30’05” S, 28°34’43” E), near the Lesotho border (SANParks 2020). The GGHNP is situated on the Highveld, which is an inland plateau at the foothills of the Maloti Drakensberg Mountain range, covering an area of 340 km² (Botham et al. 2020; Groenewald 1986; SANParks 2020). The GGHNP was established in 1963 with the intention of protecting and conserving the montane, Afro-alpine grassland biome and sandstone formations (SANParks 2020; Taru, Chingombe & Mukwada 2013).

The study area is located within the summer rainfall region, with rainfall restricted from November to April (Daemane et al. 2022; Grab et al. 2011; Groenewald 1986; Moffett 2018) and occurs in the form of thunderstorms (Van Zyl 2003). Late afternoon thunderstorms are mostly accompanied by hail and some lightning (Moffett 2018; Van Zyl 2003). The average mean annual rainfall of the area is 800 mm – 1820 mm, with periodic snowfall and frost in winter months on the highest peaks as well as summer mist (Cooks & Pretorius 1987; Groenewald 1986; MacKellar, New & Jack 2014; Moffett 2018). The area mostly experiences warm summers and cold winters (Grab et al. 2011).

The vegetation of GGHNP is dominated by sour grass, occurring in high rainfall areas on leached soils (Mucina & Rutherford 2006). These grasslands are seen as stable because of a dense cover of grasses (Tainton 1999). Vegetation types (Figure 2) found in the Park include the Basotho Montane Shrubland (Gm5), Eastern Free State Sandy Grassland (Gm4), Lesotho Highland Basalt Grassland (Gd8), Northern Drakensberg Highland Grassland (Gd5), and Drakensberg-Amathole Afromontane Fynbos (Gd6) where this study is focused (Figure 2) (Mucina & Rutherford 2006; Mukwada, Chingombe & Taru 2016; SANParks 2020).

The Drakensberg-Amathole Afromontane Fynbos (Gd6) comprises fynbos elements characterised by fine-leaved, evergreen sclerophyllous shrubs whose regeneration is influenced by fire (Mucina & Rutherford 2006). Although the original map by Mucina and Rutherford (2006) only indicated the occurrence of Gd6 in Golden Gate Highlands National Park, it was also found near Harrismith on Platberg (Brand et al. 2008, 2009) and on Korannaberg near Excelsior (Du Preez 1992).

During February 2022 (the growing season), 108 sample plots were placed in three transects across the mapped sections of the Drakensberg-Amathole Afromontane Fynbos by Mucina and Rutherford (2006) and that proposed by Du Preez (2017). The modified Braun-Blanquet cover abundance scale (Table 1) was used to record all vascular plants in the combined mapped sections of Gd6. Plots were 10 m × 10 m (Bredenkamp & Brown 2003; Brown et al. 2013; Du Preez 1992; Grobler, Bredenkamp & Brown 2002) with 10 m between each sampling plot along the transect. Unknown species sampled were stored and identified at the Geo Potts Herbarium (BLFU) at the University of the Free State. Bulbs, succulents and geophytes were photographed instead of sampled if they could not be identified.

Field data were captured in VegCap, a Macro-enabled Excel spreadsheet developed by Dr Nacelle Collins. Captured data were then imported into JUICE (Tichy & Holt 2006), where a modified TWINSPAN (Hill 1979) analysis (two-way-indicator species analysis) was conducted. The Table from JUICE was refined using Braun-Blanquet procedures (Brown et al. 2013). JUICE was also used to calculate and distinguish between dominant and diagnostic species (Brown et al. 2013) using the analysis of the Columns of a Synoptic Table function. Threshold frequencies were set to 75, 60 and 50, respectively, for diagnostic, dominant and constant species (Theron, Van Aardt & Du Preez 2020). This was only carried out for the communities. Species indicated in bold had values higher than the threshold values, while * indicates alien invasive species in the phytosociological table (Online Appendix 1).

To conduct correspondence analysis (CA), species data were uploaded into CANOCO (Ter Braak & Smilauer 2002). Biplot scaling was used to focus the analysis on inter-species distance. No transformation of the species data was carried out, and rare species were not down-weighted. To determine the different plots surveyed, basic ordination plots were drawn using CANOCO. Various combinations of the first, second and third axes were used, and diagrams best presenting the vegetation observed in the field are shown in the results and discussion. An environmental gradient of rocky outcrops and deeper soils was used and fitted to the axis as it was observed in the field during data collection.

Ethical approval was obtained from the Environmental and Biosafety Ethics Committee at the University of the Free State (UFS-ESD2023/0037/3) on 10 May 2023.

The classification results below indicate communities, sub-communities and variants of the Gd6 vegetation of the mapped sections by Mucina and Rutherford (2006) and the proposed section by Du Preez (2017). Additionally, some figures under the categories of diagnostic, dominant and constant species indicate the prevalence of those species in a community. Table 1-A1 represents the phytosociological classification of the vegetation of the two sections. Two communities with a total of four sub-communities and four variants were identified, and they are as follows:

1. Erica woodii–Passerina montana Community

Diagnostic species: None

Dominant species: Aristida junciformis 2, Diospyros whyteana 2, Erica algida 7, Erica woodii 11, Monocymbium ceresiiforme 2, Themeda triandra 2, Tristachya leucothrix 11

Constant species: Passerina montana 64, Erica woodii 73, Helichrysum auronitens 64, Tristachya leucothrix 82

The Erica woodii–Passerina montana plant community is located on the mid-slope of a mountain where there is full sun exposure. The slope is gentle to steep with some rocky outcrops on the edges of the community. The plant community consists of a mixture of ferns, herbs and shrubs characterised by Erica woodii, Passerina montana and Erica algida shrubs from Species Group A (Table 1-A1). Passerina montana shrubs can be used to distinguish this community from the rest of the communities in Table 1-A1 (Figure 3). The presence of Erica species such as E. woodii and E. algida throughout this community serves as evidence that this community is part of Gd6 because these species form part of the characteristic species described by Mucina and Rutherford (2006) for this vegetation type.

Brand et al. (2008) found an Eragrostis curvula–Eragrostis racemosa community where P. montana was a variant. In this variant, Heteropogon contortus and T. leucothrix are some of the species that had significant cover abundance values. The results of our study and those of Brand et al. (2008) are comparable because the species that were identified as characteristic in their study are the same as the species in our study. Du Preez (1992) found Passerina montana–Cymbopogon dieterlenii to be a major community. However, the community identified by Du Preez (1992) differs from the community identified in our study in terms of the species found within each of the communities. In Du Preez’s (1992) study, Passerina montana was a dominating species, whereas in our study, it occurs with high cover abundance. Mucina and Rutherford (2006) regard Passerina montana as an important species in the Gd6 vegetation type. Brand et al. (2011) indicate that the presence of P. montana confirms the presence of Gd6 as a vegetation type. Furthermore, Brand et al. (2011) indicate that Passerina montana is sclerophyllous and characterises some of the communities they found on Platberg. The occurrence of P. montana in our research is thus a clear indication that this community represents the vegetation of Gd6.

1.1 Erica woodii–Passerina montana–Digitaria monodactyla Sub-community

This sub-community is located on a rocky outcrop of a mid-slope with shallow soils that are well drained. As a result of heavy rainfall in summer, water tends to collect on the rocks, creating rockpools. The sub-community is defined by grasses and herbs from Species Group B (Table 1-A1), including Digitaria monodactyla, Wahlenbergia krebsii, Stiburus alopecuroides and Aristida congesta. These species occur with high cover abundance in this sub-community and with little or no cover abundance in other sub-communities. Brand et al. (2008) described a community called Helichrysum dasycephalum–Digitaria monodactyla community where Digitaria monodactyla is one of the dominating species. The community described by Brand et al. (2008) is located on a flat rocky ridge on the steep and exposed mid-slopes where the soils are well drained. The community described by Brand et al. (2008) is like the sub-community described in our study in terms of location and species found. This sub-community can be divided into two variants.

1.1.1 Crassula dependens Variant

This variant occurs on a steep south-facing mid-slope, on the sandstones of the Clarens Formation. The soil collecting on the rocky outcrops is approximately 8 cm – 10 cm deep. Soil and nutrients from runoff are collected in the rocks and create an ideal environment for Crassula dependens (Species Group C; Table 1-A1) to grow. This environment is ideal for these species to grow because the soil contains abundant moisture during the rainy season. The vegetation is dominated by Aristida junciformis (Species Group E), Erica woodii (Species Group A), Tristachya leucothrix (Species Group L) and Crassula dependens (Species Group C), having high cover abundance values (Table 1-A1). Most of the species occurring in Species Group C are absent or occur with low cover abundance in other communities and sub-communities. Although this variant was not described in any of the available literature by Du Preez (1992) and Brand et al. (2008, 2009), the species that are found within the variant are similar to the species found by these researchers, for example, Crassula dependens and Oxalis depressa from Species Group C.

1.1.2 Afroaster perfoliatus Variant

This variant is located on a mid-slope with rocky outcrops and is defined by species from Species Group D (Table 1-A1), which includes Afroaster perfoliatus, Senecio othonniflorus, Senecio harveianus, Melinis repens, Hypoxis costata, Chrysocoma ciliata, Hypoxis hemerocallidea, Ficinia stolonifera, Satyrium longicauda, and Ledebouria cooperi. These species have little or no cover abundance in the rest of the communities. This variant is dominated by Afroaster perfoliatus from Species Group D in Table 1-A1. Neither Du Preez (1992) nor Brand et al. (2008, 2009) found similar associations in their studies.

1.2 Erica woodii–Passerina montana–Aristida junciformis Sub-community

This sub-community is located on a mid-slope and is dominated by grasses, herbs and shrubs from Species Group E (Table 1-A1). Vegetation in this sub-community is exposed to strong sunlight and the soils are well drained, although there are signs of wetness because of water damming on the rocks after heavy rainfall during summer. The strong presence of Aristida junciformis and Erica alopecuroides distinguishes this sub-community from the other sub-communities. Aristida junciformis is considered an important indicator species by Mucina and Rutherford (2006) within the Gd6 vegetation type.

2. Cymbopogon pospischilii–Cotula hispida Community

Diagnostic species: None

Dominant species: Cymbopogon pospischilii 6, Themeda triandra 23

Constant species: Cymbopogon pospischilii 77, Selago flanaganii 81, Themeda triandra 90, Tristachya leucothrix 62

The Cymbopogon pospischilii–Cotula hispida Community is located on a mountain in a mid-slope position where there is deep soil with some stones. The community receives strong sunlight but retains moisture well after heavy rainfall. This is a grassland community dominated by C. pospischilii (Species Group F) and T. triandra (Species Group J) (Table 1-A1). The species that distinguish this community from community 1 are Cymbopogon pospischilii and Cotula hispida (Species Group F), which occur with low cover abundance values in the other communities. This can be a new community or a community that indicates disturbance as it was not previously found in research about Gd6. In literature, C. hispida is indicative of disturbance and therefore, its presence in this community indicates a disturbance (Fish et al. 2015). However, species that occur in this community but are not characteristic were found by previous research to be present in Gd6. These species are indicated in blue on the phytosociological table (Table 1-A1) and include Lotononis lotononoides, Andropogon appendiculatus (Species Group H), Eragrostis chloromelas, Eragrostis curvula, Crassula lanceolata, Cheilanthes eckloniana (Species Group I), and Vernonia hirsuta (Species Group J) (Brand et al. 2008, 2009; Du Preez 1992; Mucina & Rutherford 2006).

2.1 Cymbopogon pospischilii–Cotula hispida–Lotononis lotononoides Sub-community

The sub-community is located on a steep mid-slope with isolated patches of rocks with shallow soils. Cymbopogon pospischilii (Species Group F) and Themeda triandra (Species Group J) dominate this community, with Lotononis lotononoides and Pelargonium sidoides (Species Group G) having high cover abundance values (Table 1-A1) and dominating this sub-community. The other species such as Crassula natalensis, Panicum natalense, Diascia integerrima, Andropogon appendiculatus, Scabiosa columbaria, Moraea brevistyla, Helichrysum tenax, Nemesia fruticans, and Cynoglossum hispidum (Species Group G) are also characteristic of this sub-community and have little cover abundance in the other communities. There are also species that correspond to what Du Preez (1992) and Brand et al. (2008, 2009) found during their studies, including Andropogon appendiculatus and L. lotononoides (Species Group G).

2.2 Cymbopogon pospischilii–Cotula hispida–Helichrysum auriceps Sub-community

This sub-community is located on the mid-slope of the Clarens and Drakensberg Formation where there are about 10% rocky outcrops. The soils found were black (which might be indicative of high organic matter content) and damp. Species such as Cymbopogon pospischilii and Themeda triandra (Species Group H) dominate this sub-community with high cover abundance values (Table 1-A1). Brand et al. (2009) described an Asparagus ramosissimus–Leucosidea sericea–Fraxinus angustifolia Sub-community, which was located on sandstones of the Clarens Formation. The soils in the sub-community described by Brand et al. (2009) were deep, black and damp. The sub-community in our study is similar to that described by Brand et al. (2009) in terms of the location as well as the high cover abundance of Leucosidea sericea (Species Group H):

2.2.1 Selago densiflora Variant

This variant is located on a mid-slope that receives full sun exposure with well-drained soils. It is characterised by species from Species Group I (Table 1-A1), which are mostly grasses, shrubs and herbs. This variant is distinguished from variant 2.2.2 because of the absence or low cover abundance values of species from Species Group I (Table 1-A1). The dominating species in this variant include Cymbopogon pospischilii (Species Group F) and Themeda triandra (Species Group J). The variant consists of four species from Species Group I, highlighted in blue, which include Eragrostis chloromelas, Eragrostis curvula, Crassula lanceolata, and Cheilanthes eckloniana, which were also found by researchers (Brand et al. 2008, 2009; Du Preez 1992; Mucina & Rutherford 2006) working on Gd6-related vegetation.

2.2.2 Eragrostis racemosa Variant

This variant is characterised by species from Species Group J, with Vernonia hirsuta (Species Group J) (Table 1-A1) also found by Brand et al. (2008, 2009) in their description of Gd6 vegetation. These species have a strong presence in this variant, with little or no cover abundance in the other communities. The variant is dominated by the grass Eragrostis racemosa.

The CA resulted in a clear grouping of two different communities (Figure 4), similar to the phytosociological classification, consisting of the grassland community (Cymbopogon pospischilii–Cotula hispida) and the fynbos community (Erica woodii–Passerina montana) occurring on rocky outcrops. There are, however, some plots in the communities that are common to both communities. Given that transects were sampled across the proposed and mapped sections, these overlapping plots might be indicative of ecotonal areas.

Families found in the study area that had more than four species are all included in Figure 5. Asteraceae and Poaceae are the most prominent families found in the study area. Fabaceae, Cyperaceae and Schrophulariaceae also have a high number of individuals occurring within the study area.

Fynbos is mostly dominated by ericoid shrubs that are fine-leaved, which include Ericaceae, Asteraceae, Rhamnaceae, Thymelaeaceae, Rutaceae, Restionaceae, and Proteaceae (Mucina & Rutherford 2006). Important families in the Cape Fynbos include Fabaceae, Iridaceae, Aizoaceae, Ericaceae, and Schrophulariaceae (Goldblatt & Manning 2000). However, when the families are ranked, the top 10 families include: Asteraceae, Fabaceae, Iridaceae, Ericaceae, Aizoaceae, Schrophulariaceae, Restionaceae, Proteaceae, Rutaceae, and Orchidaceae. Poaceae is ranked 11th among the families present in the fynbos (Manning & Goldblatt 2012). In Figure 5, the families in the orange legend represent those from the fynbos found in the study area.

Grasslands, however, are structurally simpler and mostly dominated by Poaceae. The three largest families in the Grassland Biome are Asteraceae, Poaceae and Fabaceae (Retief & Meyer 2017). In Figure 5, the families coloured in blue represent those from the grassland found in the study area.

Asteraceae and Poaceae are regarded as the two largest plant families on Platberg and are also common in the DAC (Carbutt & Edwards 2001). These two families are the most prominent within the study area. Although Poaceae and Cyperaceae dominate the grasslands, when it comes to the Fynbos biome, this environmental and floristic position is filled by Restionaceae. The dominance of Poaceae and Cyperaceae is also evident in our study. We can therefore say that the combination of families found in this study is a further indication that there are fynbos elements within the grassland.