Van Staden Woud.Qxd 2006/04/17 08:38 PM Page 15

Home , Afromontane, Grewia occidentalis, Marakele National Park, Olea capensis, Podocarpus latifolius, Widdringtonia nodiflora

van staden woud.qxd 2006/04/17 08:38 PM Page 15

A floristic analysis of forest and thicket vegetation of the Marakele National Park

P.J. VA N STADEN & G.J. BREDENKAMP

Van Staden, P.J. and G.J. Bredenkamp. 2006. A floristic analysis of forest and thicket vegetation of the Marakele National Park. Koedoe 49(1): 15–32. Pretoria. ISSN 0075- 6458. One of the major plant communities identified in the Marakele National Park was forest. It became clear that this major forest community contained various forest and thicket communities. Relevés compiled in the forest were classified by TWINSPAN and Braun-Blanquet procedures identified six communities that are hierarchically classified. The forests dominated by Podocarpus latifolius and Widdringtonia nodiflora represent Afromontane Forests, whereas the Buxus macowanii-dominated dry forests and Olea europaea subsp. africana represent Northern Highveld Forests. A further group of communities represent thickets on termitaria with floristic affinities to both savanna and forest. The floristic composition and relationships of the forest and thicket communities are discussed. Key words: Afromontane forest, Afrotemperate forest, classification, National Park, termitaria, thicket, TWINSPAN.

PJ van Staden, Centre for Wildlife Management, University of Pretoria, Pretoria, 0001 Republic of South Afirca; GJ Bredenkamp , Department of Botany, University of Pre- toria, Pretoria, 0001 Republic of South Afirca ([email protected]).

Introduction Van Staden (2002) indicated that various plant communities occurred within these In an overview of the vegetation of Marakele forests, though they are not yet described. National Park, Van Staden & Bredenkamp This paper aims to describe the forest plant (2005) recognised five major plant commu- communities of the Marakele National Park, nities, of which one represents forests. These to provide an inventory of the biodiversity of forests are mostly restricted to moist, shel- the plant community at the plant species tered valleys, and represent typical Marakele level. Afromontane Forest (Von Maltitz 2003). Although Du Preez et al. (1991) classified this type of forest as typical Afromontane Study area Forests, the Marakele forests exist under much drier conditions than in the Drakens- The study area was described in detail by Van berg (Von Maltitz 2003). These forests occur Staden (2002) and Van Staden & Bre- in specific niches in deep valleys, protected denkamp (2005), and are therefore only gorges and ravines along the eastern and briefly mentioned here. The study area cov- western slopes of the Drakensberg mountain ers 290.51 km² in the southwestern part of range. the Limpopo Province between 27°30'E– 27°45'E and 24°15'S–24°30'S. Marakele Indeed, some of the Marakele forests are National Park is situated mainly in the Water- very dry and represent a very rare and berg Moist Mountain Bushveld (Low & restricted plant community classified by Von Rebelo 1996), in the Savanna Biome Maltitz (2003) under Northern Highveld (Rutherford & Westfall 1994). The vegeta- Forests. tion of the study area includes Acocks’

ISSN 0075-6458 15 Koedoe 49/1 (2006) van staden woud.qxd 2006/04/17 08:38 PM Page 16

(1988) Sour Bushveld (Veld Type 20), too small to delineate. Additional sample plots were Mixed Bushveld (Veld Type 18), Sourish subjectively placed within the termitaria vegetation. Mixed Bushveld (Veld Type 19) and North- For the purpose of this study, a standard sample plot Eastern Mountain Sourveld (Veld Type 8). size of 10 m x 20 m was fixed and used throughout The underlying parent rock of the biggest the study area. This plot size is considered adequate part of the study area consists of sandstone for surveys in savanna vegetation by Coetzee (1975), of the Kransberg Subgroup, Sandriviersberg Coetzee et al. (1976), Westfall (1981), Van Rooyen Formation. Sandstone of the Matlabas Sub- (1983) and Gertenbach (1987). group, Aasvoëlkop Formation, occurs in the At each sample plot a list is compiled of all the southwestern and southern parts; shale and species that occur. A cover-abundance value was mudstone of the Matlabas Subgroup given to each species according to the cover-abun- Aasvoëlkop Formation, Groothoek Mud- dance scale, used by Braun-Blanquet and given by stone Member; a conglomerate outcrop of Mueller-Dombois & Ellenberg (1974) and Werger the Matlabas Subgroup, Aasvoëlkop Forma- (1974), and modified by Barkman et al. (1964): tion are found in the western part. These rock formations resulted in the complex mountain 5 - Any number of plants, with cover >75 % of the sample plot. topography of the Waterberg. Within this 4 - Any number of plants, with cover > 50–75 % of complex topography, the forests are restrict- the sample plot. ed to the relatively moist kloofs, mostly with 3 - Any number of plants, with cover > 25–50 % of small rivers. the sample plot. 2a -Covering between 5–12 % of the sample plot The soils that have developed on the parent area independent of abundance (indicated as A in materials range from shallow sandy to deep the tables). sandy soils on sandstone and clayey soils on 2b -Covering between 13–25 % of the sample plot area independent of abundance (indicated as B diabase and mudstone. in the tables). The rainfall varies from 556 mm to 630 mm 1 - Numerous, with cover of 5 % or less. + - Individuals with cover of < 1 %. per annum and occurs mainly during the r - Usually a single individual with a cover of summer months. This is considerably lower <1%. than the rainfall limits described for forests in summer rainfall area by Rutherford & Although Van Staden (2002) recorded various habi- Westfall (1994). The study area experiences tat variables, only the following habitat classes are used in this study (see Table 1): warm, wet summers with temperatures of up to 32 ºC and cool dry winters with frost in The altitude of each sample plot was recorded using the low-lying areas. an altimeter and is given in meters. The slope of the terrain of each sample plot was measured in degrees, using an optical clinometer. Methods The following classification of slope units (Westfall 1981), were used in this study: Analysis Symbol Description Class In the overview of the vegetation of the Marakele L level 0.00° - 3.49° National Park, Van Staden (2002) used 130 sample G gentle 3.50° - 17.62° plots, located in a stratified random manner in M moderate 17.63°- 36.39° physiographically and physiognomically homoge- S steep 36.40° neous units, delineated on 1:50 000 scale aerial pho- The aspect of the terrain where each sample plot is tographs (Bredenkamp & Theron 1978; Westfall situated was determined using a compass. Aspect is 1981; Gertenbach 1987). The number of sample given in the eight compass directions, namely: plots for each delineated physiographic-physiog- nomic unit was determined according to the size of N - North S - South each delineated unit. Termitaria were not included in NE - Northeast SW - Southwest the placing of the sample plots. Although they could E - East W - West be recognised on the aerial photographs, they were SE - Southeast NW - Northwest

Koedoe 49/1 (2006) 16 ISSN 0075-6458 van staden woud.qxd 2006/04/17 08:38 PM Page 17

The surface rock cover in each sample plot was esti- on the Marakele National Park as the Olea mated as a percentage of stones (> 20 mm diameter), europaea subsp. africana-Diospyros whyteana boulders and rocky outcrops. The following five Major Community. Obvious variation in plant classes were used, based on its potential influence on species composition and dominance was mechanical use (ploughing) (Van der Meulen 1979; observed within this major community. The Westfall 1981): floristic composition of the Olea europaea Symbol Class Description subsp. africana-Diospyros whyteana Major O < 1 % No limitation on mechanical Community is given in Table 1. utilisation Van Staden & Bredenkamp (2005) described L 1 - 4 % Low limitation on mechanical this major community as having a large utilisation M 5 - 34 % Moderate limitation on number of diagnostic species, all being trees mechanical utilisation or shrubs, which distinguish this forest vege- H 35 - 84 % High limitation on mechanical tation from any other plant community utilisation occurring in the park. These diagnostic V 85 - 100 % No mechanical utilisation species included Pappea capensis, Mimu- possible sops zeyheri, Olea europaea subsp. africana, Land type was read from the Land Type maps. Cussonia paniculata, Diospyros whyteana, Euphorbia ingens, Rhus leptodictya, Cryp- tolepis transvaalensis, Podocarpus lati- Synthesis folius, Maytenus undata, Zanthoxylum The full dataset was captured on the mainframe com- capense, Myrsine africana, Canthium gilfil- puter of the University of Pretoria, in the BBNEW lanii, Ficus sur, Calpurnia aurea, Olea software package. It was then exported to be used in capensis and Grewia occidentalis. the software package BBPC (Bezuidenhout et al. Although different plant communities can be 1996). After a TWINSPAN classification (Hill 1979), the output of the resulting classification was import- recognised within these forests and bush ed into a spreadsheet, for refinement by Braun-Blan- clumps, certain species, e.g., Olea europaea quet procedures (Behr & Bredenkamp 1988). The subsp. africana, Ficus sur, Cryptolepis final classification of the relevés was then interpret- transvaalensis, Cussonia paniculata and ed for identification of major communities for the Euphorbia ingens were prominent through- entire park. The relevés representing the forests and out the range of this major community. thickets were then extracted, subjected to TWINSPAN (Hill 1979) and exported to be used in the software The forest communities occur in the kloofs, package BBPC (Bezuidenhout et al. 1996) for or as thickets in bush clumps on south and refinement by Braun-Blanquet procedures. The east-facing slopes and also as dense thickets results are summarised in a phytosociological table on termitaria on the plains. The kloofs are (Table 1). the most sheltered of the geomorphology classes found in the study area, with water in the watercourses draining down the kloofs. Results These kloofs are also protected against the veld fires that occur frequently in the adja- The phytosociological classification of cent savanna or grassland vegetation. forests and thickets in the study area resulted Geldenhuys (1994) described a similar situa- in the identification of five forest communi- tion for forests in the Western Cape. ties with one of the communities having two sub-communities. Coetzee (1975) described a related community from the Rustenburg Nature Reserve as Hypoestes verticillaris-Mimusops zeyheri Olea europaea subsp. africana-Diospyros Forests, and Westfall (1981) described a sim- whyteana Major Community ilar community from the Farm Groothoek in Van Staden & Bredenkamp (2005) identified the Waterberg as Kloof Forest Communities the forest and thicket vegetation that occur on moderately deep soils in moist, sheltered

ISSN 0075-6458 17 Koedoe 49/1 (2006) van staden woud.qxd 2006/04/17 08:38 PM Page 18 Table 1 Table Phytosociological table of the forests and bush clumps on Marakele National Park Phytosociological table of the forests

Koedoe 49/1 (2006) 18 ISSN 0075-6458 van staden woud.qxd 2006/04/17 08:38 PM Page 19 (continued) Table 1 Table

ISSN 0075-6458 19 Koedoe 49/1 (2006) van staden woud.qxd 2006/04/17 08:38 PM Page 20 (continued) Table 1 Table

Koedoe 49/1 (2006) 20 ISSN 0075-6458 van staden woud.qxd 2006/04/17 08:38 PM Page 21 (continued) Table 1 Table

ISSN 0075-6458 21 Koedoe 49/1 (2006) van staden woud.qxd 2006/04/17 08:38 PM Page 22 (continued) Table 1 Table

Koedoe 49/1 (2006) 22 ISSN 0075-6458 van staden woud.qxd 2006/04/17 08:38 PM Page 23

habitats. Du Preez et al. (1991) classified 1.2 Buxus macowanii-Kirkia wilmsii Dry this type of forest as typical Afromontane Low Forest. Forests, where these forests occur in specific niches in deep valleys, protected gorges and 2 Pappea capensis-Ziziphus mucronata Thickets ravines along the eastern and western slopes and Bush Clumps of the Drakensberg mountain range. Coetzee 2.1 Rhus leptodictya-Mimusops zeyheri et al. (1976) described termitaria bush clump Termitarium Thickets. communities from the Nylsvley Nature 2.1.1 Rhus leptodictya-Carissa Reserve. These have diagnostic species sim- bispinosa sub-community 2.1.2 Rhus leptodictya-Berchemia ilar to the bush clump communities on ter- zeyheri sub-community mitaria in the Marekele National Park. 2.2 Olea europaea subsp. africana- Calpurnea aurea Tall Closed Woodland. In the hierarchical phytosociological classification, the following plant communities are A dendrogram showing the habitat relation- classified under the Olea europaea subsp. ships of the various plant communities is africana-Diospyros whyteana Major Com- shown in Fig. 1. munity (Table 1): 1. Olea capensis-Cheilanthes viridis Forest 1 Olea capensis-Cheilanthes viridis Forest 1.1 Podocarpus latifolius-Curtisia dentata This community represents all the forests Forest that occur in moist kloofs or sheltered val- 1.1.1 Widdringtonia nodiflora- leys in the Marakele National Park. Based on Podocarpus latifolius Moist species composition, this vegetation can be Short Forest. 1.1.2 Podocarpus latifolius-Rothmannia regarded as Afromontane Forest (White capensis Moist Tall Forest. 1978). According to the classification of

Olea europaea- Diospyros whyteana Major Community

1. Dense Forest 2. Dense Thicket Pristine Degraded Ib Land Type Mostly Ad Land Type Shallow lithosols Mostly Yellow Apedal Soils > 50 % Rock cover 0-30 % Rock Cover

2.2 Southern Slopes 1.1 Moist & Cool 1.2 Dry & Warm 2.1 Flat Plains Ad & Ib Land Types Perennial/Seasonal Streams Seasonal Stream Ad Land Type Shallow Rocky Soils Southern & Eastern Slopes Northern & Western Slopes Deep Yellow Apedal Soils Termitaria 30 % Rock Cover 0 % Rock Cover

1.1.1 1.1.2 2.1.1 Large 2.1.2 Small Steep Sandstone Bush Clumps Bush Clumps Ravines Slopes 25 m diameter 11 m diameter

Fig. 1. A dendrogram showing the habitat relationships of the plant communities classified under the Olea europaea- subsp. africana-Diospyros whyteana Major Community.

ISSN 0075-6458 23 Koedoe 49/1 (2006) van staden woud.qxd 2006/04/17 08:38 PM Page 24

South African forests by Von Maltitz (2003), These Northern Afrotemperate Forests are, the forests of the Waterberg area represent according to Von Maltitz (2003), restricted to Marakele Afromontane Forests and Northern mountains and low ridges (Strydpoortberg, Highveld Forests, both these types being Waterberg, Pilanesberg, Witwatersrand, classified under the Northern Afrotemperate Magaliesberg, Suikerbosrand, Sekhku- Group of forests. The Olea capensis- khuneland) interrupting the relatively flat Cheilanthes viridis Forest represents a north- northern highveld grassland or bushveld. western island of Afromontane (White 1978) The forests are found in kloofs on the north- or Afrotemperate (Von Maltitz 2003) forests. ern and eastern flanks of the Drakensberg. Within the study area this community is The diagnostic species of Podocarpus lati- characterised by species group E (Table 1), folius-Curtisia dentata Forest are listed with the trees Olea capensis and Canthium under species group C, with the trees gilfillanii and the ferns Cheilanthus viridis Podocarpus latifolius, Curtisia dentata, and Pellaea calomelanos as the diagnostic Rothmannia capensis, Faurea saligna, Rhus species. Olea capensis, in particular, can be dentata, Myrsine africana and Ochna holstii, regarded as a typical forest species, though the liana Secamone alpinii and the sedge the other three species may occur wide- Cyperus albostriatus as diagnostic species. spread on rocky areas of the Waterberg and The tall-growing Podocarpus latifolius is Bankenveld (Bredenkamp & Brown 2003; mostly the dominant species, locally reach- Van Staden & Bredenkamp 2005). ing a cover of up to 70 %. These forests can be subdivided into Podocarpus latifolius-Curtisia dentata For- 1.1.1 Widdringtonia nodiflora-Podocarpus est, restricted to moist, sheltered valleys, and latifolius Short Forest representing typical Marakele Afromontane Forest (Von Maltitz 2003), and Buxus Typical: relevé 130 macowanii-Kirkia wilmsii Dry Low Forest, a Habitat very specialized dry forest, representing a very rare and restricted plant community The Widdringtonia nodiflora-Podocarpus classified by Von Maltitz (2003) under latifolius Short Forest is found at high alti- Northern Highveld Forests. tudes, 1500 m–1730 m a.s.l. along perennial streams and deep, sheltered, moist kloofs, on 1.1 Podocarpus latifolius-Curtisia dentata gentle to moderate (6–22°) east and south- Forest facing sandstone slopes within the Ib Land Type. The soils are of the Mispah Form These forests represent the typical moist derived from sandstone of the Sand- short to tall forests of the Waterberg area, riviersberg Formation, and the soil is relatively shallow (< 500 mm) (Land Type Sur- Tall Forest is found at 1300 m–1730 m a.s.l. vey Staff 1988). along perennial or seasonal streams and moist kloofs. This forest community is a rep- Although this community is not totally pro- resentative of North-Eastern Mountain tected from fire, the woody vegetation and Sourveld (Acocks 1988), Afromontane For- structure are seldom damaged due to the est (White 1978) and typical Marakele poorly developed grass layer and the high Afromontane Forest (Mucina & Van Staden percentage rock cover that provides shelter 2003), classified under the Northern against fire. Large rocks cover more than Afrotemperate Forest Group (Von Maltitz 76 % of the soil surface. During the rainy 2003). This is a local forest type found only season and for some time thereafter, water on the Waterberg, Marakele National Park constantly seeps from the sandstone, creat- (Van Staden 2002) and some kloofs of ing an ideal moist habitat where this com- Magaliesberg (Coetzee 1975). munity is typically found.

Koedoe 49/1 (2006) 24 ISSN 0075-6458 van staden woud.qxd 2006/04/17 08:38 PM Page 25

Floristics and structure tic species in common with the Ilex mitis- Pittosporum viridiflorum Forest Community The Widdringtonia nodiflora-Podocarpus described by Coetzee (1975) and the Kloof latifolius Short Forest is differentiated by the Forest Communities described by Westfall following diagnostic plant species (species (1981). This community occupies the most group A, Table 1): the woody Widdringtonia mesic habitats of sheltered parts of kloofs on nodiflora, Pittosporum viridiflorum, Ilex the eastern side of the Waterberg Mountain. mitis, Halleria lucida, Syzygium cordatum The dominant woody species Widdringtonia and Cliffortia linearifolia; the shrubby Clu- nodiflora and Podocarpus latifolius are, tia pulchella and Phylica paniculata; the however, absent from the forest communities ferns Blechnum giganteum, Pteridium aquil- described by Coetzee (1975). inum, Asplenium splendens and Cheilanthus hirta; and the forb Gerbera piloselloides. Communities 1.1.1 and 1.1.2 are floristically related through the mutual presence of the This community is represented by five species of species group B, emphasised relevés and an average of 19 species was especially by Podocarpus latifolius, Curtisia recorded per sample plot. dentata, Rothmannia capensis and Myrsine The tree layer is on average 8.4 m tall with africana. These forests are also remotely an average canopy cover of 79 % (Table 2). related to Buxus macowanii-Kirkia wilmsii Widdringtonia nodiflora is totally dominant, Low Forest (Community 3), through species whereas Podocarpus latifolius may locally group E (Table 1). be very prominent. Apart from the diagnostic woody species, other prominent trees are 1.1.2 Podocarpus latifolius-Rothmannia Curtisia dentata, Canthium gilfillanii capensis Tall Forest. (species group C), and Olea capensis (species group E). The latter species has a Typical: relevé 109 wider distribution within various forest com- Habitat munities in the park (Table 1). The Podocarpus latifolius-Rothmannia The shrub layer is on average 1.4 m tall, with capensis Tall Forest is found at 1300 m– an average canopy cover of 22 % (Table 2). 1660 m a.s.l. along perennial or seasonal Prominent shrubs occurring in this commu- streams and moist kloofs on sandstone nity are Myrsine africana and Ochna holstii slopes (4–30°), facing southeast, north, (species group C) (Table 1). The woody liana northeast and east. It is represented by five Secamone alpinii (species group C) is fre- relevés and an average of 26 species was quently found in the tree and shrub strata. recorded per sample plot. This forest com- The herbaceous layer has an average height munity is a representative of Acocks’ (1988) of 0.5 m and an average canopy cover of North-Eastern Mountain Sourveld, with the 11.0 % (Table 2). It is dominated by the diag- structure as a tall forest (Edwards 1983) and nostic ferns Blechnum giganteum, Pteridium it all occurs in the Ib Land Type (Land Type aquilinum and Asplenium splendens (species Survey Staff 1988). group A) and the sedge Cyperus albostriatus During the rainy season and for some time (Species Group C) as ground cover in the thereafter water constantly seeps from the more open areas. The tree fern, Cyathea sandstone, creating an ideal moist habitat, dregei, which was not recorded in any sam- characteristic for this community. The soils ple plots, also occurs as isolated individuals are of the Mispah Form derived from sand- in the forests in the study area. stone of the Sandriviersberg Formation, and the average soil depth is relatively shallow General (< 500 mm) (Land Type Survey Staff 1988). The Widdringtonia nodiflora-Podocarpus Large rocks cover more than 70 % of the soil latifolius Short Forest has many characteris- surface.

ISSN 0075-6458 25 Koedoe 49/1 (2006) van staden woud.qxd 2006/04/17 08:38 PM Page 26

Floristics and structure Podocarpus latifolius Short Forest, both being classified under the Podocarpus lati- The Podocarpus latifolius-Rothmannia capensis folius-Curtisia dentata Forest. Tall Forest is differentiated by the diagnostic following plant species (species group B, Table 1): the woody Combretum moggii, 1.2 Buxus macowanii-Kirkia wilmsii Strychnos usambarensis, Pterocelastrus Low Forest echinatus, Celtis africana, Tetradenia bre- vispica, Solanum giganteum, Dovyalis zey- Typical: relevé 64 heri, Englerophytum magalismontanum, Habitat Pavetta gardeniifolia, Diospyros lycioides and Nuxia congesta; the herbaceous Aspara- The Buxus macowanii-Kirkia wilmsii Low gus setosum; and the grass Oplismenus Forest is found at 1110 m–1250 m a.s.l. The hirtellus. Buxus macowanii-Kirkia wilmsii Low Forest is restricted to hot, dry kloofs of north fac- The tree layer is on average 12 m tall with an ing, east and northwest-facing slopes (2– average canopy cover of 79 %. Other promi- 29°) of the study area (Fig. 1) This low for- nent trees are Pittosporum viridiflorum est occupies a relatively drier and warmer (species group A), Podocarpus latifolius and habitat than the Podocarpus latifolius-Cur- Curtisia dentata (species group C), Cussonia tisia dentata Forest. paniculata, Ficus thonningii, Olea europaea subsp. africana, Euphorbia ingens, Ficus sur The structure of this forest community is a (species group K), Mimusops zeyheri low forest (Edwards 1983) and it occurs in (species group J), and Olea capensis (species the Ib Land Type (Land Type Survey Staff group E). The tree fern Cyathea dregei, 1988). The soils are of the Mispah Form which was not recorded in the sample plots, derived from sandstone of the Sandriviers- also occurs in this community. berg Formation, and the soil is relatively shallow (< 500 mm) (Land Type Survey Staff The shrub layer is on average 1.7 m tall with 1988). Rocks cover more than 50 % of the an average canopy cover of 49 %. Apart soil surface. from the diagnostic species, other prominent shrubs occurring in this community are Myr- Floristics and structure sine africana (species group C), Canthium The Buxus macowanii-Kirkia wilmsii Low gilfillanii (species group E), and Diospyros Forest is represented by four relevés and an whyteana and Grewia occidentalis (species average of 23 species was recorded per sam- group K). The woody liana Secamone alpinii ple plot. It is differentiated by the following and Cryptolepis transvaalensis are frequent- woody plant species (species group D): ly found in the tree and shrub strata. Buxus macowanii, Kirkia wilmsii, Apodytes The herbaceous layer has an average height dimidiata, Ochna pretoriensis, Croton of 0.5 m and an average canopy cover of gratissimus, Euphorbia turicalli, Acacia 22 %. It is dominated by Cyperus albostria- ataxacantha and Heteromorpha trifoliata. tus and Oplismenus hirtellus. The tree layer is on average 7.8 m tall, with General an average canopy cover of 35 %. Other prominent trees are Mimusops zeyheri, This community is closely related to the Berchemia zeyheri, Dombeya rotundifolia Celtis africana-Osyris lanceolata Kloof For- (species group J) and Olea europaea subsp. est described by Westfall (1981). These two africana, Cussonia paniculata and Euphor- communities have many distinctive habitat bia ingens (species group K). features and many, distinctive species in common. The Podocarpus latifolius-Roth- The shrub layer is on average 2.3 m tall, with mannia capensis Tall Forest is floristically an average canopy cover of 84 %. Prominent related to the Widdringtonia nodiflora- shrubs occurring in this community are

Koedoe 49/1 (2006) 26 ISSN 0075-6458 van staden woud.qxd 2006/04/17 08:38 PM Page 27

Ochna pretoriensis, Croton gratissimus, 2. Pappea capensis-Ziziphus mucronata Euphorbia tirucallii and Acacia ataxacantha Thickets and Bush Clumps (species group D), Diospyros whyteana, and and Heteropyxis natalensis (species group K). Dombeya rotundifolia subsp. rotundifolia, Berchemia zeyheri and Ziziphus mucronata The herbaceous layer has an average height (species group J) show strong floristic affini- of 0.3 m and an average canopy cover of ties between these thickets and the Buxus 7 %. The herbaceous layer is poorly repre- macowanii-Kirkia wilmsii Dry Low Forest. sented and is dominated by the xerophytic ferns Cheilanthes viridis and Pellaea calo- 2.1 Rhus leptodictya-Mimusops zeyheri melanos (species group E). Termitarium Thickets General Typical: relevé 18 Westfall (1981) described an Erythrina lysis- temon-Celtis africana Kloof Forest with Habitat Buxus macowanii as a conspicuous woody The Rhus leptodictya-Mimusops zeyheri Ter- species with more than 5 % mean canopy mitarium Thickets are found from 1160 m– cover and occurring in more than 50 % of the 1300 m a.s.l. This widespread community relevés. This community is similar to the occupies an even drier habitat than that of community found in the study area. These the Buxus macowanii-Kirkia wilmsii Low shrubs are often gregarious, forming pure Forest, though the termitaria are moister than stands (Table 1). The distribution of the the surrounding savanna (Van der Meulen tree/shrub, Buxus macowanii, is restricted to 1979). They are therefore classified with the warm valleys and coastal dunes in the East- forests. The bush clumps on termitaria are ern Cape, with the Limpopo Province popu- restricted to the Ad Land Type on level and lation as an unexpected outlier (Coates- gentle slopes (Land Type Survey Staff 1988) Palgrave 1983). This could indicate a former (Fig. 1). Afromontane forest biogeographic connec- tion via the Waterberg and Stydpoort Moun- Before proclamation of Marakele National tains to the northeastern escarpment and also Park, this community was subjected to heavy to the Blouberg and western Soutpansberg. grazing by cattle and the field layer varies in height and cover depending on soil salinity The Buxus macowanii-Kirkia wilmsii Dry and the amount of grazing (Coetzee et al. Low Forest, a very specialised dry forest, 1981). The vegetation developed on huge representing a very rare and restricted plant termite mounds to form this specific plant community classified by Von Maltitz (2003) community. The size of these termitaria under Northern Highveld Forests. According determines the type of vegetation that to Von Maltitz (2003), these latter forests are occurs. The trees are usually very tall restricted to Suikerbosrand (Bredenkamp & because of the depth and aeration and the Theron 1978, 1980), Witwatersrand (Behr & fine texture and higher nutrient status of the Bredenkamp 1988; Ellery et al. 2001), soil (Coetzee et al. 1976). Magaliesberg (Coetzee 1974, 1975), Water- berg (Westfall 1981; Westfall et al. 1985; This community is a representative of Van Staden 2002), Sekhukhuneland (Siebert Acocks’ (1988) Sour Bushveld, with the 2001), and some other ridges occurring structure as a short closed woodland throughout the western Central Bushveld (Edwards 1983) region (Van Vuuren 1961; Van Vuuren & Floristics Van der Schijff 1970; Van der Meulen 1979). These forest patches are imbedded within an The Rhus leptodictya-Mimusops zeyheri Ter- ecotone between sourveld grasslands and mitarium Thickets are differentiated by the subtropical savannas of the Central following diagnostic plant species (species Bushveld. group G, Table 1): the woody Rhus lepto-

ISSN 0075-6458 27 Koedoe 49/1 (2006) van staden woud.qxd 2006/04/17 08:38 PM Page 28

dictya, Euclea crispa, Grewia flavescens, The tree layer is on average 7 m tall with an Flueggia virosa, Ficus thonningii and Pavet- average canopy cover of 79 %. Other promi- ta zeyheri; the liana Asparagus transvaalen- nent trees are Pappea capensis and Schotia sis; the grass Eragrostis curvula; the herba- brachypetala (species group I), Olea capen- ceous Schistostephium heptalobum; and the sis (species group E), Mimusops zeyheri, weedy annual Tagetes minuta. Dombeya rotundifolia subsp. rotundifolia, Berchemia zeyheri and Ziziphus mucronata (species group J), and Olea europaea subsp. 2.1.1 Rhus leptodictya-Carissa bispinosa variation africana, Ficus sur, Cussonia paniculata and Grewia occidentalis (species group K). Typical: relevé 18 The shrub layer is on average 1.4 m tall, with an average canopy cover of 46 %. Prominent Habitat shrubs are Grewia flavescens, Flueggia The Rhus leptodictya-Carissa bispinosa virosa (species group K) and Calpurnia variation is found at 1160 m–1300 m a.s.l. aurea (species group H). This variation occurs on level ground or/and The herbaceous layer has an average height gentle slopes (1-160º). The soils are yellow, of 0.4 m and an average canopy cover of apedal and well drained and relatively deep 20 %. It is dominated by the grass Panicum (> 500 mm), belonging to one of the follow- maximum and Eragrostis rigidior, the forbs ing forms: Inanda, Kranskop, Magwa, Hut- Pavonia burchelli, Schkuhria pinnata and ton, Griffin and/or Clovelly (Land Type Sur- Lippia javanica (species group F). vey Staff 1988) (Fig. 1). General The average diameter of the Rhus lepto- Coetzee et al. (1976) described similar com- dictya-Carissa bispinosa variation bush munities from flat bottomlands with termi- clumps is 25 m. It is represented by seven taria at Nylsvley Nature Reserve, namely the relevés and an average of 35 species was Pappea capensis-Acacia tortilis variation recorded per sample plot (Table 1). which shows strong affinities with the Rhus Floristics and structure leptodictya-Carissa bispinosa variation, with the most common plant species being The Rhus leptodictya-Carissa bispinosa Carissa bispinosa and Pappea capensis. variation is differentiated by the following diagnostic plant species (species group F, 2.1.2 Rhus leptodictya-Berchemia zeyheri Table 1): the woody Carissa bispinosa, variation Gymnosporia buxifolia, Vangueria infausta, Clerodendrum glabrum, Adenia glauca, Typical: relevé 16 Dichrostachys cinerea, Gardenia volkensii, Habitat Psiadia punctulata, Aloe marlothii, Acacia karroo, Maerua angolensis and Pterocarpus The Rhus leptodictya-Berchemia zeyheri rotundifolius; the forbs Pavonia burchelli, variation is found at 1250 m–1360 m a.s.l. Sida dregei, Kalanchoe rotundifolia, The soils are the same as for the Rhus lepto- Schkuhria pinnata, Lippia javanica, Sida dictya-Carissa bispinosa variation, but here cordiifolia, Anthospermum hispidulum, Ipo- the bush clumps are much smaller, with an moea magnusiana, Hemizygia pretoriae, average diameter of 11 m, whereas the aver- Solanum panduraeforme, Scadoxus puniceus; age diameter of the bush clumps Rhus lepto- and the grasses Panicum maximum, Aristida dictya-Carissa bispinosa variation is 25 m. congesta, Eragrostis rigidior, Eragrostis Floristics and structure lehmanniana and Cynodon dactylon. This variation is represented by four relevés Many of these diagnostic species indicate and an average of 35 species was recorded previous over-utilisation and trampling. per sample plot. Although it seems that no

Koedoe 49/1 (2006) 28 ISSN 0075-6458 van staden woud.qxd 2006/04/17 08:38 PM Page 29

diagnostic species occur in this variation, it dendron capense, Gymnosporia polyacan- can be distinguished from the Rhus lepto- tha, Vepris lanceolata and Tricalysia lanceo- dictya-Carissa bispinosa variation by the lata, the herbaceous Asparagus virgatus and absence of species in the species group F and the grass Setaria lindenbergiana. the presence of species in species group H The tree layer is on average 10.5 m tall with (Table 1), with Maytenus undata, Calpurnea an average canopy cover of 56 %. Other aurea and Calodendron capense being dif- prominent trees are Celtis africana (species ferential species. group B); Rhus leptodictya, Euclea crispa, The tree layer is on average 6.5 m tall with Ficus thonningii (species group G); Pappea an average canopy cover of 66 %. The shrub capensis, Ziziphus mucronata, Zanthoxylum layer is on average 1.6 m tall with an average capense, Schotia brachypetala, Euclea canopy cover of 46 %. The herbaceous layer natalensis and Acacia caffra (species group has an average height of 0.4 m and an aver- I); Mimusops zeyheri and Berchemia zeyheri age canopy cover of 10 %. (species group J); and Olea europaea subsp. africana, Ficus sur and Euphorbia ingens 2.2 Olea europaea subsp. africana-Calpurnea (species group K). aurea Tall Closed Woodland The shrub layer is on average 1.8 m tall with an average canopy cover of 41 %. Cryp- Typical releve: relevé 97 tolepis transvaalensis is prominent. Habitat The herbaceous layer has an average height The Olea europaea subsp. africana- of 0.4 m and an average canopy cover of Calpurnea aurea Tall Closed Woodland is 21 %. The herbaceous layer is dominated by found from 1180–1500 m a.s.l. in deep the grass Setaria lindenbergiana and the forb kloofs on southwest-facing and south-facing Hypoestes forskaolii (species group K). sandstone slopes (2–250º), usually along General seasonal streams (Table 1, Fig. 1). This bush clump community is a representative of The Olea europaea subsp. africana-Calpurnia Acocks’ (1988) Sour Bushveld, with the aurea Tall Closed Woodland has floristically structure as a tall closed woodland (Edwards strong affinities with the Rhus leptodictya- 1983). It occurs on the Ad Land Type and the Mimusops zeheri Termitarium Thickets Ib Land Type (Fig. 2.7) (Land Type Survey (species group I) and especially the Rhus Staff 1988). The soils are of the Mispah leptodictya-Berchemia zeyheri variation, Form derived from sandstone of the Sand- indicated by species group H. The habitat difference between these two bush clump riviersberg Formation (Land Type Survey communities is that the Olea europaea Staff 1988) and large rocks cover more than subsp. africana-Calpurnia aurea Tall Closed 31 % of the soil surface (Fig. 1). Woodland occurs in deep, sheltered kloofs Floristics and structure on rocky substrates without termitaria, while the Rhus leptodictya-Berchemia zeyheri The Olea europaea subsp. africana- variation occurs on termitaria on the plains Calpurnea aurea Tall Closed Woodland is without rocks. characterised by the presence of species group H and absence of species group G. No diagnostic species group was identified, though the species of species group H are Discussion differential, it also indicates a floristic rela- According to White (1978) the majority of tionship with the Rhus leptodictya- the tree species in the Afromontane forests Berchemia zeyheri variation (community are very widespread. Amongst them are 2.1.2). The differential species are the woody Podocarpus latifolius, Ilex mitis and Halle- Maytenus undata, Calpurnia aurea, Calo- ria lucida that occur in the study area. These

ISSN 0075-6458 29 Koedoe 49/1 (2006) van staden woud.qxd 2006/04/17 08:38 PM Page 30

species could almost be used to define the Acknowledgements Afromontane region as a whole. Not one South African National Parks is thanked for the species occurs throughout, but most species opportunity to use the offical research project for a of the assemblage are represented on virtual- MSc degree. ly every ‘island’ of Afromontane forest.

According to Von Maltitz (2003) the North- References ern Highveld Forest type is a relict forest type in a progressed stage of ‘erosion’ from ACOCKS, J.P.H. 1988. Veld types of South Africa, 3rd edn. Memoirs of the botanical Survey of South the original Afromontane composition. They Africa 57: 1–146. are considered remnants of the Magaliesburg BARKMAN, J.J., J. MORAVEC & S. RAUCHERT. 1964. Extension (White 1978)—an Afromontane Kritische Bemerkungen und Vorschläge zur (forest) intrusion linking the forests of quantitativen Vegetationanalyse. Acta Botanica Neerlandia 13: 394–449. Northern Escarpment to those found in shel- BEHR, C.M. & G.J. BREDENKAMP. 1988. A phytosoci- tered sites of the Central Bushveld and ological classification of the Witwatersrand Northern Highveld regions. These forests are National Botanical Garden. South African Jour- nal of Botany 54: 525–533. Afrotemperate (Afromontane) in character, BEZUIDENHOUT, H., H.C.BIGGS & G.J. BREDENKAMP. however Holocene climate changes have 1996. A process supported by the utility BBPC caused their confinement to fire-sheltered for analysing Braun-Blanquet data on a personal computer. Koedoe 39(1): 107–112. habitats and a concomitant decline in forest BREDENKAMP, G.J. & L.R. BROWN. 2003. A reap- elements, but an increase in woodland ele- praisal of Acocks’ Bankenveld: Origin and ments (Von Maltitz 2003). diversity of vegetation types. South African Journal of Botany 69(1): 7–26. This fragmentary Afromontane type forest BREDENKAMP, G.J. & G.K. THERON. 1978. A syneco- forms transitions to surrounding savanna and logical account of the Suikerbosrand Nature Reserve. 1. The phytosociology of the Witwater- to the riverine forests with Combretum ery- srand geological system. Bothalia 12: 513–529. throphyllum (Van Rooyen 1983; Von Maltitz BREDENKAMP, G.J. & G.K. THERON. 1980. A syneco- 2003). There is also floristic similarity logical account of the Suikerbosrand Nature Reserve, Part II: The phytosociology of the Ven- between the kloof forest communities and tersdorp geological system. Bothalia 13(1&2): thickets found on termitaria. Termitaria are 199–216. known to increase water infiltration and per- COATES PALGRAVE, K. 1983. Trees of Southern colation, as well as nutrient availability, Africa. 2nd ed. Cape Town: Struik. COETZEE, B.J. 1974. A phytosociological classifica- compared to the surrounding savanna wood- tion of the vegetation of the Jack Scott Nature lands (Van der Meulen 1979). Therefore, ter- Reserve. Bothalia 11: 329 – 347. mitaria do support dense thickets with savan- COETZEE, B.J. 1975. A phytosociological classification of the Rustenburg Nature Reserve. Bothalia na species, however some forest species are 11: 561–580. also present. COETZEE, B.J., F. VAN DER MEULEN, S. ZWANZIGER, P. G ONSALVES & P.J.WEISSER. 1976. A phytoso- Low diversity of the woody element places ciological classification of the Nylsvley Nature this type close to Drakensberg Montane Reserve. Bothalia 12: 137–160. Forests and Northern KwaZulu-Natal Mist- COETZEE, B.J., P. VAN WYK, W.P.D. GERTENBACH, A. HALL-MARTIN & S.C.J. JOUBERT. 1981. 'n belt Forests (Von Maltitz 2003). Plantekologiese verkenning van die Water- berggebied in die Noord-Transvaalse Bosveld. The distribution of the shrub Buxus macow- Koedoe 24:1–23. anii is of biogeographic interest. This species DU PREEZ, P.J., G.J.BREDENKAMP & H.J.T. VENTER. is restricted to coastal forests of the Eastern 1991. The syntaxonomy and synecology of the forests in the eastern Orange Free State, South Cape and forms an outlying population in the Africa. I. The Podocarpetalia latifolii. South Waterberg region (Coates Palgrave 1983). African Journal of Botany 57: 198–206.

Koedoe 49/1 (2006) 30 ISSN 0075-6458 van staden woud.qxd 2006/04/17 08:38 PM Page 31

EDWARDS, D. 1983. A Broad-scale structural classifi- taxonomic and synecological study. Vaduz: cation of vegetation for practical purposes. Cramer. (Dissertationes Botanica 49.) Bothalia 14 (3 & 4): 705–712. VAN ROOYEN, N. 1983. Die Plantegroei van die ELLERY, W.N., K. BALKWILL & K. ELLERY, R.A. Roodeplaatdam-natuurreservaat II. Die plantge- REDDY. 2001. Conservation of the vegetation on meenskappe. South African Journal of Botany 2: the Melville Ridge, Johannesburg. South African 115–125. Journal of Botany 67: 261–273. VAN STADEN, P. J. 2002. An Ecological Study of the GELDENHUYS, C.J. 1994. Bergwind patches and the Plant Communities of the Marakele National location of forest patches in the southern Cape Park. M.Sc. thesis, University of Pretoria, Preto- landscape South Africa. Journal of Biogeogra- ria. phy 21: 49–62. VAN STADEN P.J. & G.J. BREDENKAMP. 2005. Major GERTENBACH, W.P.D. 1987. 'n Ekologiese studie van plant communities of the Marakele National die Suidelikste Mopanieveld in die Nasionale Park. Koedoe 48(2): 59–70. Krugerwildtuin. D.Sc proefskrif, Universiteit VAN VUUREN, D.R.J. 1961. 'n Ekologiese studie van van Pretoria, Pretoria. 'n noordelike en suidelike kloof van die Maga- HILL, M.O. 1979. TWINSPAN – a Fortran program for liesberge. M.Sc. thesis, Universty of Pretoria, arranging multivariate data in an ordered two Pretoria. way table by classification of individuals and VAN VUUREN, D.R.J. & H.P. VAN DER SCHIJFF. 1970. attributes. Ithaca, New York: Cornell University. 'n Vergelykende ekologiese studie van die LAND TYPE SURVEY STAFF. 1988. Land types of the plantegroei van 'n noordelike en suidelike kloof maps 2426 Thabazimbi, 2428 Nylstroom. Mem- van die Magaliesberg. Tydskrif vir Natuurweten- oirs of the agricultural natural Resoures of skappe 10: 16–75. South Africa No.10: 1–431. Von Maltitz, G. (Project leader). 2003. Classification MUCINA, L. & P.J. VAN STADEN. 2003. Marakele system for South African indigenous forests: An Afromontane Forests. Pp. 99–104. In: VON objective classification for the Department of MALTITZ, G. (Project leader). Classification system for South African indigenous forests: An Water Affairs and Forestry. Pretoria: Council for objective classification for the Department of Scientific and Industrial Research. (Environ- Water Affairs and Forestry. Pretoria: Council for mentek report ENV-P-C 2003-017). Scientific and Industrial Research. (Environ- WERGER, M.J.A. 1974. On concepts and techniques mentek report ENV-P-C 2003-017). applied in the Zürich-Montpellier method of MUELLER-DOMBOIS, D. & H. ELLENBERG. 1974. Aims vegetation survey. Bothalia 11(3): 309–323. and Methods of Vegetation Ecology. New York: WESTFALL, R.H. 1981. The plant ecology of the farm Wiley. Groothoek, Thabazimbi District. M.Sc. thesis, RUTHERFORD, M.C. & R.H. WESTFALL. 1994. Bio- University of Pretoria, Pretoria. mes of southern Africa: An objective categoriza- WESTFALL, R.H., N. VAN ROOYEN & G.K. THERON. tion. Memoirs of the Botanical Survey of South 1985. The plant ecology of the farm Groothoek, Africa 63: 1–94. Thabazimbi District. 2. Classification. Bothalia SIEBERT, S.J. 2001. Vegetation of the ultramafic soils 15: 655–688. of the Sekhukhuneland Centre of Endemism. WHITE, F. 1978. The Afromontane region. Pp. Ph.D. thesis, Universty of Pretoria, Pretoria. 465–513. In: WERGER, M.J.A. (ed.). Biogeogra- VAN DER MEULEN, F. 1979. Plant sociology of the phy and ecology of Southern Africa. The Hague: Western Transvaal Bushveld. South Africa: Syn- Junk.

ISSN 0075-6458 31 Koedoe 49/1 (2006)