The phytosociology of the Villiers – Grootvlei area, South Africa. 4. The plant communities of the Ea Land Type

S.AfrJ.Bot., 1993, 59(2): 235 - 246

235

The phytosociology of the Villiers - Grootvlei area, South Africa. 4. The plant communities of the Ea Land Type P.J.J. Breytenbach,*t W.J. Myburgh,t G.K. Theron and G.J. Bredenkamp Departmentof Botany, University of Pretoria, Pretoria, 0002 Republic of South Africa t Present address: Roodeplaat Grassland Institute, Private Bag X05, Lynn East, 0039 Republic of South Africa Received 15 May 1992; revised 24 November 1992

The vegetation of the Ea Land Type in the Villiers - Grootvlei area was classified by means of BraunBlanquet procedures. A total of 77 releves in the land type were used. On the high-lying areas two major plant communities were encountered, one of which was divided into two sub-communities. On the low-lying areas five major plant communities were recorded, one of which was divided into five sub-communities and another into two sub-communities. A DECORANA ordination confirmed that the communities are related to specific environmental conditions. Die plantegroei van die Ea-Iandtipe in die Villiers - Grootvlei omgewing is deur middel van die Braun-Blanquet prosedure geklassifiseer. 'n Totaal van 77 releves is in die landtipe uitgeplaas. Op die hoerliggende areas is twee hoofplantgemeenskappe ge"identifiseer, waarvan een onderverdeel is in twee sUbgemeenskappe. Op die laerliggende areas is vyf hoofplantgemeenskappe ge'identifiseer, waarvan een onderverdeel is in vyf en 'n ander in twee subgemeenskappe. 'n DECORANA ordening het bevestig dat die plantgemeenskappe aan spesifieke omgewingstoestande gekoppel kan word. Keywords: Braun-Blanquet, classification, DECORANA, plant communities . • To whom correspondence should be addressed.

Introduction The White Paper on Agricultural Policy refers to the decline of the natural pasturage and warns that indiscriminate landuse practices and the over-exploitation of the natural resources may lead to a decrease in the living standards of the human population. The recovery and wise utilization of veld as a natural resource should receive careful attention, not only from a research point of view but also in terms of agricultural extension (Department of Agriculture and Water Supply 1986). The veld type description of Acocks (1988) is the only vegetation classification available for the Villiers Grootvlei area of the Highveld region. For this reason a more detailed vegetation classification, with an associated habitat analysis, is an urgent necessity. The aim of this study was primarily to identify, describe and classify the plant communities of the Villiers - Grootvlei area. We further aimed to investigate the reaction and interaction of vegetation with the environment (Edwards 1972, 1979). The study area was chosen as a key area for future extrapolation to surrounding areas, as it represents a geographical link between the grasslands of the western and eastern parts of the Grassland Biome. Vegetation classifications of the Bb, Ba and Ib land types have been reported elsewhere (Breytenbach et al. 1992; 1993a, b). In this report a classification and description of the plant communities of the Ea Land Type are presented.

The study area The 26280C GROOTVLEI topocadastral map (1:S0 0(0) was used as the base map for the study. The entire study area is situated between 26°4S'S and 27°00'S and between 28°30'E and 28°4S'E. The area comprises an area of

approximately 700 km2 (70 ()()() ha) in the vicinity of Grootvlei, southern Transvaal, and a small area adjacent to Villiers in the northern Orange Free State was also included (Figure 1). A detailed description of the environment of the study area was presented by Breytenbach et al. (1992). Within the study area, the Ea Land Type comprises 38 SOO ha of the total study area (Figure 2). The dominant soils of the Ea Land Type are of the Avalon, Arcadia, Rens-

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236

S.-Afr.Tydskr.Plantk.• 1993.59(2)

Africa (Bredenkamp 1975; Van Rooyen 1978). The Rangeland Ecology Section of the Roodeplaat Grassland Institute (Department of Agricultural Development) advocates this approach. The fact that many other researchers in the Grassland Biome (Bredenkamp 1975; DeaU 1985; Bezuidenhout 1988; Bloem 1988; Turner 1989; Kooij 1990) successfully used the Ziirich-Montpellier approach, contributed to its selection. Furthermore, the compatibility of results obtained by this methodology ensures a successfull ultimate synthesis of all grassland types into an appropriate synecological and syntaxonomical system. The vegetation was sampled by using stratified random sample plots. Experiments during the reconnaissance phase of the study area revealed that adequate information may be obtained with the sub-quadrat method. in terms of time and energy spent. A stratified random method was used for the location of the sample plots. The sub-quadrats were rectangular with the sides in the proportion of two to one, since this is more effective than square quadrats (Oosting 1956; Cain & Castro 1959). In accordance with Turner (1989), the number of sub-quadrats (3 x 1.5 m) were increased until the increase of species became less than 10%. A minimum of three sub-quadrats per sample plot was maintained, representing a minimum area of 13;5 m2 • The location of the sample plots were objectively chosen by using random coordinates generated by computer. The floristic survey included all species recognized during the survey and the Braun-Blanquet cover-abundance values (Werger 1974) for each species were recorded. The crown cover of the vegetation of the Bankenveld (Veld Type 61) (Acocks 1988), and the basal cover of the vegetation of the other veld types of Acocks (1988) were measured using a cover meter (Westfall & Panagos 1984). Myburgh et al. (1992) surveyed the Banken veld in the Grootvlei area and their data are incorporated in this study. The plant species names are in accordance with Gibbs Russell et at. (1985, 1987) and were also presented by Breytenbach (1991).

1 N

[~}1%::~~I~ Figure 2

E a Land Type

Skm

The location of the Ea Land Type in the study area

(Land Type Survey Staff 1984).

burg and Bonheim forms (MacVicar et al. 1977). The predominant geology of this land type is shale, sandstone, dolerite, alluvium and grit of the Ecca Group, Karoo Sequence (Department of Mineral and Energy Affairs 1986). The dominant terrain units of the Ea Land Type are unit 3 (60% of the area) within the slope class 2 - 8% and terrain unit 1 (30% of the area) within the slope class 2 - 5% (Land Type Survey Staff 1984). The average annual rainfall of the area is 670.3 mm (Land Type Survey Staff 1984). Releves were compiled in 77 sample plots in the Ea Land Type (Figure 2).

Results The vegetation of this land type occurs on high-lying and low-lying areas within the study area.

Methods The Ziirich-Montpellier phytosociological approach (BraunBlanquet 1932; Werger 1974) and the PHYTOTAB program package (Westfall et al. 1982) were used to define and describe the different plant communities. This is the most popular and acceptable approach presently used in South

A. The low-lying vegetation: the Themeda triandra Eragrostis curvula Grassland The vegetation of the low-lying areas can be described as a

1.1 1.2.2 1.2.4 1.2.5

COMMUNITIES

I

1. 2 .1 1.2.3 r--1

1.3.1 1.3.2 1.4

1.5 TERRAIN UNITS 1450m

Figure 3

3

3

3 4

5

------------------------------

4

The location of the communities of the low-lying areas in the Ea Land Type on terrain units (see text for community names).

S.Afr.J.Bot..1993.59(2)

Themeda triandra - Eragrostis curvula Grassland. Species with high cover values in this grassland are the graminoids Themeda triandra. Eragrostis curvula. Cynodon dactylon. Setaria sphacelata and Aristida congesta (species group O. Table 1). On average, 19 species per sample plot were recorded. This grassland community occurs on red or yellow soils of the Clovelly, Westleigh, Bonheim, Pinedene, Bainsvley, Avalon and Hutton forms (MacVicar et al. 1977), brown to dark brown soils of the Valsrivier, Katspruit and Mispah forms (Mac Vicar et al. 1977) and on black vertic soils of the Arcadia and Rensburg forms (Mac Vicar et al. 1977). The soil depth varies between 150 and 1200 mm and the clay content from less than 6% to more than 55%. This grassland is situated at an altitude of 1500 - 1600 m above sea-level on slopes with an inclination of 0 - 4°, on terrain units 3, 4 and 5 (Figures 3 and 4). The above-ground rock cover varies between 0 and 20%. There are no shrubs or trees present. The Themeda triandra - Eragrostis curvula Grassland can be divided into five communities and seven sub-communities, namely (Table 1; Figure 4): 1.1 Eragrostis curvula - Pogonarthria squarrosa Grassland 1.2 Themeda triandra - Elionurus muticus Grassland 1.2.1 Themeda triandra - Digitaria ternata Grassland 1.2.2 Themeda triandra - Pseudognaphalium luteo-album Grassland 1.2.3 Themeda triandra - Urginea sp. Grassland 1.2.4 Themeda triandra - Brachiaria serrata Grassland 1.2.5 Eragrostis curvula - Feliciafascicularis Grassland 1.3 Themeda triandra - Chaetacanthus burchellii Grassland 1.3.1 Themeda triandra - Chloris virgata Grassland 1.3.2 Themeda triandra - Aristida bipartita Grassland 1.4 Eragrostis curvula Schoenoplectus decipiens Grassland 1.5 Eragrostis curvula - Eragrostis plana Grassland.

237

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The Eragrostis curvula - Pogonarthria squarrosa Grassland occurs mainly on sandy (0 - 6% clay) soils of the Cloverly, Avalon and Hutton forms (MacVicar et al. 1977) with parent material that consists of Aeolian sand, sandstone and shale (Department of Mineral and Energy Affairs 1986). The community is situated at an altitude of 1500 - 1540 m above sea-level on slopes with an inclination of 0 - 2° on relatively upland sites in the undulating terrain (terrain units 1, 3 and 4). No above-ground rocks occur in this community. On average, 18 species per sample plot were recorded. The community is characterized by the diagnostic grass species Pogonarthria squarrosa. Aristida junciformis. A. sciurus. Stipagrostis zeyheri and the forb Kohautia amatymbica (species group A, Table 1), all typical of the more sandy soils. Dominant grasses in the community are Eragrostis curvula. Aristida congesta. Cynodon dactylon and Setaria sphacelata (species group 0, Table 1). Species such as the graminoids Trichoneura grandiglumis. Aristida bipartita and Eragrostis gummiflua and the forbs Solanum panduriforme. Crassula lanceolata. Commelina africana. Bulbostylis contexta and Solanum supinum also occur constantly

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238

S.-Afr.Tydskr.Plantk.• 1993.59(2)

Table 1 Phytosociological table of the low-lying areas of the Ea Land Type in the Villiers - Grootvlei area. South Africa Comnunity number

1.1

1.2 1. 2 . 1

1. 2.2

1.3

1. 2.3 1. 2.

1.2 . 5

'I

1.4

1.5

1. 3 . 1 1.3.2

000000 1110011 01101010110 000 001000 000000011000 00000 000 000 000000100 11102-' 3133902 91090901019 '1 '15 392'123 161131323553 0020" 2'11 G76 505696290 210030 0713026 7232'1905913 900 0'10219 09672'1152200 75260 01.9 503 19305'1009

Rclcve number:>

SpeCies group A

fogonarehria squJrrosa Ariseida junciformes

112 11 12 21 I 1221 I I 22 I 1+++ + I

Ariscida sciurus

Stipagroseis zeyheri Kohaue i a ant.ltymbica

·3 1

Species group B

Clionurus muticus fficrochloa caffra

111111 111 12211211+21+1 1+1 + 1 11 +1 1+ 1 + 111111+ 1+

1111 1++

11 I

11 21 I I

I + I I I I

+1 I I I I I + 1+ +1 I I

+1

Species group C

Chaeeacanchus coscatus Cvolvulus alsinoides fanicum coloraeum Oigi tari .., tarnf1ta

Aristida

1+++11+++1+ 1++1 +1 1++ 11 I 11 1 I I 111 I

I 1+ I I I

stjpjt~ta

+

+

I 1+ + I 1 11 I

I +1 1 I I I

11

Species group 0

Salvia rep ens Solanum pandurifornte Trichoneura gr.wdiglumis fseudognaphalium luceo-album

11 +11 I I + RI/1+ n I + + + 11 I 11+++ ++ I I

1+ + III 111 I

11

+ 11 n +

I I +1 I

Species group E 11 1+ 11 I /+/1 + + + /

Abi Jdg.1i1rdif1 ave't"

Ariscida di,'fusa

Hansonia lfnguscirol ia

TrifOlium JfricanuPl

1++++1 + I 11++ 11 1111 + R I 1+ 1+ ++lRRn I

n / / I RI +

11 ++ I I I R+

I I I R /

I +1 I + I R /

Species group F Urglnac' species

Cragroscis species ffariscus species Cyanocis spaciosa

+

I / I In

R

1R

11111+ 1+111 111RI 1+ It I

+

+ / / I 1+

RI / I /

Spocios group G + 1++1 ++11+111 1+1 111+1 11111+11 +11 11111 +1 +11111 11+1+1 + I

Brachiaria serrata £ragrostis racemosa

+ I I

.,. +

+ I I

I + I

+

Species group /I

Felicia fascicularis Crassu/J

lancco/clC.l

Crclbbc" hirsute1

lIalichrysum species Oicom" m.1croccph., I ,1 Caigeri., .1sper., GompfJrcn.l calosiuidas Cragrostis Ichm"nnian,l

++

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/.,

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R It

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+

Spocies group I Hormannia depress"

/ + /

lIeteropogon eOf/corcus

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I 1 +1

Species group J

Anchospermum pumilum Chaetacanthus burchalli

+

1++/1+ I + I 1++ I++RI 1"+ I RI\+/

R

i'

Rhynchost' ..1 tOtt.1

Species group K

Chloris virg.1t., Blapharis innocua

+

+

+

I I I I .1

Brachic1ric' species

Hypoxis species Vigna oblongifolia

+

+/+ 2++1 /.,+ I I +1\ I + + / / It+ I I

Species group L

Chamaesycc inaqui laCar., Aristida biparcita

+

/+ 1+

2

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+ nil ++ 3

+/ i'+++ / ++/ /112 +1+2 I

R/ I

Specios group H

Schoenoplaccus dacipians Falkia oblonga Cordylogyne globosa Senecio specias Fimbristylis compl3nat., Crinum bulbfsparmum Haplocarpha Iyraca

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I 1+ / /

I / I

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Specio. group II Eragroscis plan ..1 Barkhay~

pinnatiffda

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S.Afr.J.Bot..1993.59(2)

239

Table 1 Continued Community number

1.1

1.2 1. 2 . 1

1 . 2.2

1.3

1 . 2.3 1 . 2 . q

1. 2 . 5

1. 4

1.5

1.3.1 1.3.2

000000 1110011 01101010110 000 001000 000000011000 00000 000 000 000000100 111027 3230902 91090901019 qq5 092Q23 161131323553 0020Q ZQl G7G 505696290 210030 0713026 7232'1905913 900 0'10219 0%72'1152200 75260 01.9 503 19305'1009

Rclcvc number:.

Species group 0

[ragroscis curvula Themed., "tri.,ndr.l

121 +21121111121111121 211212111112112333323222211212212 1+23/2122123121 I +1 122213321221211222111121121233 11112+12211211312321+133211+ 11+1111 JIll I 1121 +21111 111 ++11111 I 121 1111+ +111+ +1+ 1211 I 1+ 11+11111 11 1+1 I + 2 1+11+1++1 1+1+1+/ 11 1+ 111 I 2+ 1+ 11 2 I + I I 1+++ ++1+ + H+n+l I +1+ It 'r I +n H + +1 It 1+++11 I + +HI I + 1 + 1I +I 1 13+332111 1121 21 I ,I 1 11 I I 11 + 1111 1 +

Cynodon dacey/on Setaria sphace/at. Crabbctl ole.lu! is ArisCida congest"

Species group P Schl
Cymbopogon p/urinodcs Oxa/is obliquit"oli "

Oigicaria arianc/J.l Ledebouri~ species Comma/ina arricana £ragros cis CtlpCns is Bu/bosey/ is context" So/,1num supinum / nd igofar" spac i as Species 2/1 fragroscis gUlnmifluc'

Arisclda mOI/iss/ma lIap/ocarpha scaposa Cyparus tanax

I

I I I I

I + 11+

I

I

12

I I 1++

I

• I

I

"I

R + + +

I

1

I

11111

nl I 1+ +R I I ++ + I I It I I ., + I 1++

++1 111

I

+

+

11

I n + +

n I + + I I I + I I

+ It 1 1

I

I I

I

in the community (fable 1). Of interest is the absence of near hygrophilous species such as Eragrostis plana and Berkheya pinnatifida. which are often associated with wet bottomland situations. The occurrence of the pioneer grass species Cynodon dactylon and several Aristida species indicates veld degradation. The mean basal cover of the herbaceous layer is 11 %.

1.2 The Themeda triandra - Elionurus muticus Grassland The Themeda triandra - Elionurus muticus Grassland occurs on red and yellow clayey soils from a variety of soil forms. originating from a variety of parent materials. The community is situated at an altitude of 1500 - 1600 m above sea-level on slopes with an inclination of 0 - 4°, usually on lower slopes or bottomland sites, on terrain units 3 and 4. The habitat is generally (seasonally) more moist than that of community l.l. The above-ground rock cover varies between 0 and 20%. The community is characterized by the diagnostic grass species Elionurus muticus and Microchloa caffra (species group B, Table 1). Species of species groups C - H (Table 1) are also present, but may be diagnostic for sub-communities within this community. Dominant grasses are Themeda triandra. Eragrostis curvula. Cynodon dactylon. Setaria sphacelata. Aristida congesta. Brachiaria serrata. Eragrostis racemosa. E. plana and Heteropogon contortus. The most constant forbs in the community are Hermannia depressa and Crabbe a acaulis (Table 1). The Themeda triandra - Elionurus muticus Grassland is divided into five sub-communities. 1.2.1 The Themeda triandra - Digitaria ternata Grassland The Themeda triandra - Digitaria ternata Grassland occurs on black clayey soils of the Arcadia and Rensburg forms (MacVicar et al. 1977) with a soil depth of 300 - 1200 mm

1\

++

I I

++1 +1 1+1

I +1

+

,. n

I I I I

n

I ++1+ I I I + I 1++ 11nl1 I I + +1 "1 ++ I + I 1 1 1+ I 1+1 ,. +1 I "·1 I 1 I 1 I + 1+ + 1 I I I 11 +1 +1 + I +1 I + I + I 1.1 I ++1 + +1 I 1+ 1 I I + I 1+ + 1+ .. I 1+ + I + 11 I I It I I 1\ I I I + I 1++ IIt+RI I I I I 'HI'r nl + I I +1 I I I I +. I + I I 12 1 I + I I I I I I I I + 1+ I I I I I I I

I

I n I I

1

n

I I + 1+ +

I"

+

H

I

I

I

I

I

and a clay content of more than 55%. The soils are derived from sandstone, shale and dolerite (Department of Mineral and Energy Affairs 1986). This sub-community is situated on the bottomland sites of terrain unit 4 (Figures 3 and 4). In this community above-ground rock is absent. On average, 19 species were recorded per sample plot. The sub-community is characterized by the diagnostic forb species Chaetacanthus costatus and Evolvulus alsinoides, and the grass species Panicum coloratum. Digitaria ternata and Aristida stipitata (species group C, Table 1). Dominant grasses in the community are Themeda triandra. Eragrostis curvula. Cynodon dactylon. Brachiaria serrata and Eragrostis plana. Prominent forbs in the subcommunity are Berkheya pinnatifida and Crabbea acaulis. The species of species groups B, E, G and N may also be present in this sub-community (Table 1). The mean basal cover is 11 %. 1.2.2 The Themeda triandra luteo-album Grassland

Pseudognaphalium

The Themeda triandra - Pseudognaphalium luteo-album Grassland occurs on red and yellow soils of the Westleigh, Clovelly, Bainsvley, Pinedene and Hutton forms (MacVicar et al. 1977) with clay contents that vary between 15 and 35%. Soil depth varies between 200 and 1200 mm. In the sub-community there are isolated occurrences of soils of the Arcadia and Katspruit forms (MacVicar et al. 1977). These soils are derived from dolerite, sandstone, shale, basaltic lava, agglomerate, tuff, quartzite and greywacke (Department of Mineral and Energy Affairs 1986). The sub-community is situated on terrain units 3 and 4 (Figures 3 and 4). The above-ground rock cover varies between 0 and 5%. On average, 21 species were recorded per sample plot. The community is characterized by the diagnostic forb species Salvia repens. Solanum panduriforme and Pseudognapha/ium luteo-album. and the graminoid Trichoneura grandiglumis (species group D, Table 1). Dominant grasses in the community are Themeda triandra. Eragrostis curvula.

240

Cynodon dactylon, Setaria sphacelata, Brachiaria serrata, Eragrostis racemosa, Aristida diffusa, Heteropogon contortus and Eragrostis plana. Prominent forbs are Abildgaardia ovata, Trifolium africanum, Hermannia depressa and Crabbea acaulis (Table 1). Species group E (Table 1) represents the species common for the Themeda triandra Digitaria ternata Grassland (1.2.1) and the Themeda triandra - Pseudognaphalium luteo-album Grassland, indicating some floristic relationship between these subcommunities. The mean basal cover is 10%.

1.2.3 The Themeda triandra - Urginea sp. Grassland The Themeda triandra - Urginea sp. Grassland occurs on red and yellow soils of the Pinedene and Bainsvley forms (MacVicar et al. 1977) with a clay content of 25 - 35%. The soil depth in the sub-community varies from 650 to 780 mm. The parent material of these soils is mainly Aeolian sand (Department of Mineral and Energy Affairs 1986). This sub-community is situated on terrain unit 4 (Figures 3 and 4). No above-ground rock is present. On average, 19 species were recorded per sample plot. The sub-community is characterized by species group F (Table 1) which includes the diagnostic geophyte Urginea species, the graminoid Eragrostis species, the sedge Mariscus species and the forb Cyanotis speciosa. Dominant grasses are Themeda triandra, Eragrostis curvula, Setaria sphacelata, Elionurus muticus, Microchloa caffra, Eragrostis racemosa, Heteropogon contortus and Eragrostis plana (Table 1). Hermannia depressa is a constant forb. Species of species groups B, G, I and N (Table 1) are also present in this sub-community. The mean basal cover is 13%.

1.2.4 The Themeda triandra - Brachiaria serrata Grassland As is the case with the Themeda triandra - Digitaria ternata Grassland (1.2.1), the Themeda triandra - Brachiaria serrata Grassland also occurs on dark clayey vertic soils of the Arcadia and Rensburg forms (Mac Vicar et al. 1977) with clay contents of more than 55% and depths that vary between 150 and 1200 mm. Local occurrences of the Mispah soil form (MacVicar et al. 1977) are also present in the community. The parent materials of these soils are dolerite, sandstone and shale (Department of Mineral and Energy Affairs 1986). This community seems to be situated on slightly raised and drier sites (better drained) than the Themeda triandra - Digitaria ternata Grassland (1.2.1). This is manifested in the higher prominence of Heteropogon contortus and Eragrostis racemosa and lower occurrence of Eragrostis plana. On average, 19 species were recorded per sample plot. This sub-community has no diagnostic species but it is characterized by the presence of the graminoids Brachiaria serrata and Eragrostis racemosa (species group G, Table 1), the weedy forb Chamaesyce inaequilatera and the grass species Aristidabipartita (species group L, Table 1) and the absence of species groups C - F (Table 1). Dominant grasses in the community are Elionurus muticus, Heteropogon contortus, Aristida. bipartita, Eragrostis plana, Themeda triandra and Eragrostis curvula (Table 1). The mean basal cover is 12%.

S.-Afr.Tydskr.Plantk., 1993,59(2)

1.2.5 The Eragrostis curvula - Felicia jascicularis Grassland The Eragrostis curvula - Felicia fascicularis Grassland occurs on red and brown soils of the Hutton, Katspruit, Valsrivier and Bonheim forms, and sometimes on dark clayey vertic soils of the Arcadia and Rensburg forms or on soils of the Mispah Form (MacVicar et al. 1977). The soil depth in the community varies from 260 to 1200 mm and the clay content between 15 and 55%. The parent materials of these soils are dolerite, sandstone and shale (Department of Mineral and Energy Affairs 1986). The sub-community is situated on terrain units 3 and 4 (Figures 3 and 4). The above-ground rock cover varies between 0 and 20%. This sub-community occurs on a drier habitat than the other subcommunities of the Themeda triandra - Elionurus muticus Grassland (1.2). On average, 18 species were recorded per sample plot. The sub-community is characterized by the diagnostic forb species Felicia fascicularis, Crassula lanceolata, Crabbea hirsuta , Dicoma anomala, Geigeria aspera, Gomphrena celosioides and a Helichrysum sp. and the grass species Eragrostis lehmanniana (species group H, Table 1). Dominant grasses in the sub-community are Elionurus muticus, Aristida bipartita, Eragrostis curvula, Themeda triandra, Cynodon dactylon and Aristida congesta (Table 1). Prominent forbs are Hermannia depressa and Berkheya pinnatifida. The high occurrence of species such as Aristida congesta, Felicia fascicularis and Gomphrena celosioides indicates a degraded veld due to more intensive utilization of the palatable species. Species of species groups B, I, L and N (Table 1) are also present. Species of species group I (Table 1) represent the common species for the Themeda triandra - Pseudognaphalium luteo-album Grassland, the Themeda triandra - Urginea species Grassland, the Themeda triandra - Brachiaria serrata Grassland and the Eragrostis curvula - Felicia fascicularis Grassland. The mean basal cover is 9%. 1.3 The Themeda triandra - Chaetacanthus burchellii Grassland The Themeda triandra Chaetacanthus burchellii Grassland occurs mainly on dark clayey bottomland vertic soils of the Arcadia and Rensburg forms (Mac Vicar et al. 1977) with a clay content of more than 55% and a soil depth that varies from 390 to 1200 mm. The parent materials of these soils consist of dolerite, sandstone and shale (Department of Mineral and Energy Affairs 1986). Single occurrences of soils of the Pinedene Form are also present in the community. The community is situated at an altitude of 1500 - 1540 m above sea-level on slopes with an inclination of 0 - 2° on terrain units 4 and 5 (Figures 3 and 4). The above-ground rock cover in the community varies between 0 and 5%. On average, 22 species were recorded per sample plot. The community is characterized by the diagnostic forb species Anthospermum pumilum, Chaetacanthus burchellii and Rhynchosia toUa (species group J, Table 1). Dominant grasses are Chloris virgata, Aristida bipartita, Eragrostis plana, E. curvula, Themeda triandra, Cynodon dactylon and Aristida congesta. Prominent forbs in the community are

S.AfrJ.Bot.,1993,59(2)

Chamaesyce inequilatera. Crabbea acaulis and Berkheya pinnatifida (Table 1). The mean basal cover is 9%. The Themeda triandra - Chaetacanthus burchellii Grassland is divided into two sub-communities. 1.3.1 The Themeda triandra - Chloris virgata Grassland The Themeda triandra - Chloris virgata Grassland occurs mainly on dark clayey vertic soils of the Arcadia and Rensburg forms (MacVicar et al. 1977) with a clay content of more than 55% and a soil depth that varies from 390 to 1200 mm. Localized occurrences of soils of the Pinedene Form (MacVicar et al. 1977) are also present in the community. The soils are derived from dolerite, sandstone and shale (Department of Mineral and Energy Affairs 1986). This sub-community is situated at an altitude of 1500 1540 m above sea-level on slopes with an inclination of 0 2° on terrain units 4 and 5 (Figures 3 and 4). The aboveground rock cover varies between 0 and 5%. On average, 25 species were recorded per sample plot. This sub-community is characterized by the diagnostic grass species Chloris virgata and Brachiaria sp., the forbs Blepharis innocua and Vigna oblongifolia and the geophyte Hypoxis sp. (species group K, Table 1). Dominant grasses are Aristida bipartita. Eragrostis plana. E. curvula. Themeda triandra and Cynodon dactylon . Prominent forbs are Chamaesyce inaequilatera and Schkuria pinnata (Table 1). The mean basal cover of the sub-community is 9%. 1.3.2 The Themeda triandra - Aristida bipartita Grassland The Themeda triandra - Aristida bipartita Grassland occurs on dark clayey vertic soils of the Arcadia and Rensburg forms (Mac Vicar et al. 1977) with a clay content of more than 55% and a depth that varies between 530 and 1200 mm. The parent materials of the soils are dolerite, sandstone and shale (Department of Mineral and Energy Affairs 1986). This sub-community is situated at an altitude of 1500 1540 m above sea-level on slopes with an inclination of 0 2° on terrain units 4 and 5 (Figures 3 and 4). Above-ground rock is absent. On average, 20 species were recorded per sample plot. This sub-community has no diagnostic species and is characterized by the presence of the weedy forb Chamaesyce inaequilatera and the graminoid Aristida bipartita (species group L, Table 1) and the absence of species group K (Table 1). Species group L (Table 1) is also present in the Themeda triandra - Brachiaria serrata Grassland and the Eragrostis curvula - Felicia jascicularis Grassland. Dominant grasses in the sub-community are Eragrostis plana and Themeda triandra and prominent forbs are Crabbea acaulis and Bulbostylis contexta (Table 1). The mean basal cover is 10%. 1.4 The Eragrostis curvula - Schoenoplectus decipiens Grassland The Eragrostis curvula - Schoenoplectus decipiens Grassland occurs on dark clayey soils of the Arcadia and Rensburg forms (MacVicar et al. 1977) with a clay content of more than 55% and a depth that varies between 300 and 1200 mm. The parent materials of the soils are sandstone,

241

shale and aeolian sand (Department of Mineral and Energy Affairs 1986). The community is situated at an altitude of 1500 - 1520 m above sea-level on slopes with an inclination of 0 - 1° on terrain units 4 and 5. In the community aboveground rock is absent. On average, 17 species were recorded per sample plot. The community is characterized by the following diagnostic species: the sedges Schoenoplectus decipiens and Fimbristylis complanata, the forbs Falkia oblonga. Cordylogyne globosa. Haplocarpha lyrata and Senecio sp. and the geophyte Crinum bulbispermum (species group M, Table 1). Dominant grasses are Eragrostis plana. E. curvula and Themeda triandra and the most constant forb is Oxalis obliquifolia (Table 1). Species of species group N (Table 1) are also present in the community. The vegetation has a mean basal cover of 10%. 1.5 The Eragrostis curvula - Eragrostis plana Grassland The Eragrostis curvula - Eragrostis plana Grassland occurs on red and yellow soils of the Hutton and Clovell), forms (MacVicar et al. 1977) with a clay content that varies between 0 - 6% and 35 - 55% and a depth that varies between 400 and 1200 mm. Dark clay soils of the Arcadia and Rensburg forms (MacVicar et al. 1977) with clay contents of more than 55% and depth that varies from 400 to 1.200 mm also occur in the community. The parent materials of these soils consist of dolerite, sandstone, shale andaeolian sand (Department of Mineral and Energy Affairs 1986). The community is situated at an altitude of 1500 - 1580 m above sea-level on slopes with an inclination of 0 - 3° on terrain units 4 and 5 (Figures 3 and 4). Above-ground rock is absent. On average, 14 species per sample plot were recorded. The community has no diagnostic species and is characterized by the presence of the hygrophylous grass Eragrostis plana and the forb Berkheya pinnatifida (species group N, Table 1) and the absence of species of species groups A - M (Table 1). Dominant grasses of the community are Eragrostis curvula. Themeda triandra. Cynodon dactylon. Aristida congesta and Eragrostis gummiflua. Prominent forbs are Oxalis obliquifolia and Ledebouria sp. (Table 1). The mean basal cover is 10%. B.

The high-lying vegetation of the Ea Land Type

The vegetation of the high-lying hills and slopes of the Ea Land Type can be described as a Themeda triandra Heteropogon contortus Grassland. Species of species group A (Table 2) represent the common diagnostic species for. this vegetation type and species of species group G (Table 2) represent the common species for the entire Ea Land Type. The Themeda triandra - Heteropogon contortus Grassland occurs mainly on shallow «300 mm) rocky soils derived from basalt, quartzite and red hematite. This grassland occurs at an altitude of 1520 - 1640 m above sea-level on slopes with an inclination of 0 - 15° on terrain units 1 and 3 (Figures 5 and 6). The above-ground rock cover in the grassland varies between 0 and 45%. On average, 30 species per sample plot were recorded. Dominant grasses are Heteropogon contortus. Brachiaria serrata. Elionurus muticus, Cynodon dactylon. Eragrostis curvula. Themeda triandra and Aristida congesta (Table 2).

S.-Afr.Tydskr.Plantk., 1993, 59(2)

242

Table 2 Phytosociological table of the high-lying areas of the Ea Land Type in the Villiers - Grootvlei area, South Africa Community number

1.1

1.2 Re l eve numbers

22 2211 222222 43 2211 000001 07 1240 234560

Garuleum woodi i Gladi olus specie,S Aloe trsnsvaalensis Nayeenus heterophylls Schiseoseephium craeaegif"olium Hypoxis argeneea Aleernanehera pungens Berkheya radula Cucumis zeyheri He/ichrysum ca/l i comum Hypoxis obeusa Ledebouria ovaeif"olia IJroch/oa panico ides Vernonia naea/ensis Anehericum cooperi Dicoma zey heri Diheeeropogon amp/ec eans He/ichrysum ceraseioides Ledebouria revo/uea Rhynche/yerum repens C/emaeis oweniae Proeaspsragus seeaceus Senecio venosus

Species group A

Heeeropogon coneoreus Hermsnnia depressa

Helichrysum rugu/-osum 8rachiaria serrato

Conyza podocephala £ragroseis racemosa Seoebe vulgaris Commel ina af'ricana

1211 +1111 1 1 1+ 1+ 1 11+++1+ 11+1 ++ I+R+R + I 1 I + 11 I ++++ 1+21+ I ++++R I 11+ 1+1 + IR 1+ I ++ I + I R 1+ +

Species group B

Diospyros Iycioides Felicia f"i Ii f"o Ii a Athrixia elaea Cheilanehes hirca Pellaea calomenalos Rhus discolor Nyrsine af"rjcana Lippia scaberrima Rhynchosia cocca Haemanthus humi lis Ipomoea crassipes Cussonia paniculaca £uclea crlspa Clutia hirsuca Cotoneaster pannosus

1+31 + 1221 12+1 1++1 + 1++1 1++1 I+RI I+RI I+RI IRRI

l+llR 11 I I 41 12 I

I 11

SpeCies group C

£Iionurus mutlcus

1221 112 1 1111 1++1 11 11+ I 1+ 11 '1 1+1 1+ ,++1 + ++ I 1++ IR+++ I I++IR++RI I + I + + I

Gynodon daceylon Seearia sphacelaca Ziziphus zeyheriana

Lactuc8 speci es Trif'ol ium arricanum

Trichoneura grandiglumis Spec i es group D

Trachypogon :;picaeus Aca Iypha caperoni oides Seearia pall ida-f"usca Triseachya leucoehrix Abildgaardi a ovaea Haplocarpha scaposa

+1

1111 I 111 I + 1+ 1 I 1+ 1 I I +1 I I R+I

I I I I I

Species group E

Cymbopogon plurinodes Felicia rase/cu/aris

Solanum pandurif"orme Schkuhria pinnaea

Hermannia lancira/ia

Mansonia anguscifolia

Salvia repens

Solanum supinum

Tephrosia longipes Bidens pilosa Tageeus minuea Sonchus nanus Arise/da mollissima

Oxalis obliquif"olia Pachycarpus rigidus

I

I I

I :

+1

1

I 1+ I I I I I I R I I I 11 I +1

I

I

I 1+ 1+ I I IR

1++ +1+1 1+ ++++1 I + +++1 1 +++R+I 1++ ++ 1 I +1 +1 11+ +1 I + + +1 IR++ 1 1+R+ I 1+ + R I 1+ R+I 1 1 1 1 I + RI I RR I

Species group F

-Cymbopogor. ex cavaeus Berkheya seeif"era Argyrolobium velue i num Indigof"era obscura Chaeeacanehus coseaeus Helichrysum nudif"olium Rhus rigida

11 ++ ++ +R + R +

+ 11 ++R+

++ ++ + ++ RR

+R

Spec i es group G

£ragroseis curvl1la Themeda triandra Crabbea acaulis Ariseida congesea SpeC i es group

1121111 12121121 I i1 1211212122221 1++1++++1++++++1 I + 1+ ' 1 111 1121

H

Digiearia eriant:ha £hrhartll erecea -Nicrochloa caf"f"ra £ragrostis plana Berkheya pinnaeif"ida Crassula lanceolaea £ra'groseis lehmllnnians Ariseida dif"f"usa Ledebouria species Hyparrhenia hirea Pseudognaphalium lueeo-album Vernoni Ii oligocephals Ariscida eransvaslensis Secsri.a nigriroser i s

I

I

I I

I I

1+ I

+ 1

+R

1 1+ 1 I

I 1 + I

J

I

[

I I I I +1 11

Community number

I

1. 1

1.2 1 . 2.1 1 . 2 . 2

1 . 2 . 1 1.2.2 Releve numbers

Table 2 Continued

+

1

+

+

22 22 11 222222 1I3 2211 000001 07 1240 234560 I I R + I + I 11 11 R I R I I 1 I I I 1 + I I + I R I I I 1+ I I 1+ + i I +1 I I I I R I 1 I + I I I R I IR I I I I + I I +1 I I +1 I 1+ I I

Prominent forbs are Hermannia depressa , Helichrysum rugulosum, Conyza podocephala and Crabbea acaulis (Table 2). Prominent shrubs and trees are Diospyros lycioides, Athrixia elata, Rhus discolor, Myrsine a/ricana, Cussonia paniculata, Euclea crispa and the exotic encroacher, Cotoneaster pannosa (Table 2). The Themeda triandra - Heteropogon contortus Grassland can be divided into two communities, and one of these into two sub-communities, namely: 1.1 Diospyros lycioides - Eragrostis curvula Shrubland 1.2 Themeda triandra - Elionurus muticus Grassland 1.2.1 Themeda triandra - Trac hypogon spicatus Grassland 1.2.2 Themeda triandra - Cymbopogon plurinodes Grassland

1.1 The Diospyros lycioides -

Eragrostis curvula

Shrub land

The Diospyros lycioides - Eragrostis curvula Shrubland occurs mainly on hillcrests and slopes on shallow «300 mm) rocky soils with andesite and hornfels as the parent material (Department of Mineral and Energy Affairs 1986). The community is situated at an altitude of 1600 - 1640 m above sea-level on slopes with an inclination of 11 - 15° on terrain unit 3 (Figures 5 and 6). The above-ground rock cover in the community varies between 16 and 45%. On average, 38 species were recorded per sample plot. The community is characterized by the diagnostic woody species Diospyros lycioides, Felicia /ilifolia , Rhus discolor, Myrsine a/ricana, Cussonia paniculata and Euclea crispa, the shrub Athrixia elata, the forbs Lippia scaberrima , Rhynchosia totta, Ipomoea crassipes and Clutia hirsuta, the geophyte Haemanthus humilis, the xerophytic ferns Cheilanthes hirta and Pellaea calomelanos, and the exotic encroacher Cotoneaster pannosa (species group B, Table 2). Dominant grasses in the community are Heteropogon contortus, Cymbopogon excavatus, Themeda triandra and Eragrostis curvula. Prominent forbs in the community are Conyza podocephala, Helichrysum rugulosum and Crabbea acaulis (Table 2). Species of species groups A, B, F and G

S.Afr.I.Bot., 1993, 59(2)

243

1.2.1 I

COMMUNITIES

I

1.1. I

1.2.2 I

I

I

1 TERRAIN

4

14S0m

Figure 5

~ -----------------------------

---1

3

UNITS

3 5

-.......

4

The location of the communities of the high-lying areas in the Ea Land Type on terrain units (see text for community names) .

Ea Land Type High-lying I

Inclination 11-15 0 Above-ground rock cover 16-45% Altitude 1 600 m -1 640 m Terrain units 3 en 4 Geology: Hornfels and andesite Mean crown cover 38%

Inclination 0 - 3 0 Above- ground rock cover 0-15% Altitude 1 520 m -1 600 m Terrain units 1 en 3 Geology: Basalt and quartzite Mean crown cover 62% I

I

Altitude 1 560 m -1 600 m Inclination 1-2 0

1.1

1. 2.1

I

Alt i tude 1 520 m -1 560 m Inclination 1-3 0

1. 2.2

communities

Figure 6 Dendrogram to illustrate the habitat relationships of the communities of the high-lying areas in the Ea Land Type (see text for community names).

(Table 2) are also present in the community. The mean crown cover of the community is 38%.

1.2 The Themeda triandra - Elionurus muticus Grassland The Themeda triandra - Elionurus muticus Grassland occurs mainly on the uphill sites in undulating terrain, on shallow «300 mm) rocky soils with basalt, red hematite and quartzite as the parent materials (Department of Mineral and Energy Affairs 1986). The community is situated at an altitude of 1520 - 1600 m above sea-level on slopes with an inclination of 0 - 3° on terrain units 1 and 3 (Figures 5 and 6). The above-ground rock cover in the community varies between 0 and 15%. On average, 24 species per sample plot were recorded. The community is characterized by the diagnostic grass species Elionurus muticus. Cynodon dactylon. Setaria sphacelata and Trichoneura grandiglumis, the woody dwarf shrub Ziziphus zeyheriana and the forbs Trifolium africanum and Lactuca sp. (species group C, Table 2). Dominant grasses are Brachiaria serrata. Cymbopogon plurinodes. Aristida mollissima. Eragrostis curvula. Themeda triandra and Aristida congesta. Prominent forbs are Hermannia depressa. Conyza podocephala. Felicia fascicularis . Hermannia lancifolia. Schkuria pinnata and Crabbea acaulis

(Table 2). Species of species groups A and C - G (Table 2) are also present in the community. The mean crown cover of the community is 61%. The Themeda triandra - Elionurus muticus Grassland was divided into two sub-communities.

1.2.1 The Themeda triandra - Trachypogon spicatus Grassland This sub-community is situated at a higher altitude (1560 1600 m above sea-level) than the Themeda triandra Cymbopogon plurinodes Grassland (1.2.2), on terrain unit 1 and upper parts of terrain unit 3. The shallow «300 mm) rocky soils are derived from basalt and red hematite (Department of Mineral and Energy Affairs 1986) (Figures 5 and 6). On average, 24 species per sample plot were recorded. The sub-community is characterized by the diagnostic grass species Trachypogon spicatus. Setaria pal/ide-jusca and Tristachya leucothrix, and the forbs Acalypha caperonioides. Abildgaardia ovata and Haplocarpha scaposa (species group D, Table 2), which are all characteristic species of higher altitudes and rocky terrain. Dominant grasses are Heteropogon contortus. Brachiaria serrata. Eragrostis racemosa. Elionurus muticus. Cynodon dactylon.

244

S.-Afr.Tydskr.Plantk.• 1993.59(2)

Setaria sphacelata. Cymhopogon excavatus. Eragrostis curvula and Themeda triandra. Prominent forbs in the subcommunity are Berkheya setifera. Chaetacanthus costatus and Crabhea acaulis (Table 2). Species of species groups A, C, D, F and G (Table 2) are also present in the subcommunity. Species group F represents the species common for the Diospyros lycioides - Eragrostis curvula Shrubland and the Themeda triandra - Trachypogon spicatus Grassland, indicating a floristic and ecological relationship between these two communities. The mean crown cover of the sub-community is 62%. 1.2.2 The Themeda triandra - Cymhopogon plurinodes Grassland The Themeda triandra - Cymhopogon plurinodes Grassland occurs predominantly lower down on western aspect slopes of terrain unit 3, on shallow «300 mm) rocky soils derived from basalt and quartzite (Department of Mineral and Energy Affairs 1986) (Figures 5 and 6). On average, 25 species per sample plot were recorded. The sub-community is characterized by the diagnostic grass species Cymhopogon plurinodes and Aristida mollis-

sima and the forbs Felicia fascicularis. Solanum panduriforme. Schkuhria pinnata. Hermannia lancifolia. Monsonia angustifolia. Salvia repens. Solanum supinum. Tephrosia longipes. Bidens pi/osa. Tagetes minuta. Sonchus nanus. Oxalis obliquifolia and Pachycarpus rigidus (species group E, Table 2). Many of these species are of a lower ecological status, indicating the state of degradation of the vegetation. This degradation has been caused mainly by overgrazing and trampling by cattle and sheep. Dominant grasses are Brachiaria serrata. Elionurus muticus. Cynodon dactylon. Eragrostis curvula. Themeda triandra and Aristida congesta. Prominent forbs are Hermannia depressa. Conyza podocephala. Ziziphus zeyheriana and Crabhea acaulis (Table 2). Species of species groups A, C, E and G (Table 2) are also present in the sub-community. The mean crown cover of the community is 61 %.

Ordination The data of the vegetation of the Ea Land Type was ordinated by using Detrended Correspondence Analysis (DECORANA) (Hill 1979). In the scatter diagram of the low-lying areas (Figure 7), a distinct separation between the Eragrostis

Terrain unit 1;3;4

Inclination 2 - 4°

LOW-lying

\

Red and yellow soils

300

/

/A-----------~ AI

/

I

/

I

/

/

/

/ /

/

/

/

I

/

/

I

/

/

I

/

/

(A

I

I I

200

8

I I

I I

I I

I

I I

/

/

I I I I

/

/

I I I

I

I

I I

I

AI I

I ,/

,/

100

,/

I

8

"

/

,/

A , / ,/

/

'-/

Terrain unit 4;5 High-lying

I"E------ ____ _

----

Inclination 0 _2°

-----

Dark clayey soils

E\

EI --.7

c 100

200

300

Figure 7 A DECORANA ordination of the vegetation of the low-lying areas of the Ea Land Type in the Villiers - Grootvlei area, South Africa. A, Eragrostis curvula - Pogonarthria squarrosa Grassland; B, Themeda triandra - Elionurus muticus Grassland; C, Themeda triandra - Chaetacanthus burchellii Grassland; D, Eragrostis curvula - Schoenoplectus decipiens Grassland; E, Eragrostis curvula - Eragroslis plana Grassland.

S.AfrJ.Bot.,1993,59(2)

245

250~--------------~---------------------------------------------------.

Less steep slopes (0 - 3°) Low-lying (1520 - 1560m)

Steep slopes (11 -15°)

Dolerite, diabase

Basaltic lava, agglomerate, tuff

200

,,/ //

"

/B

I

150

"

I

B

High . lying (1600 - 1640m)

,../ . . . . 8'\ \

Above-ground rock

\ \

\

0 - 45

%

Terrain units 3 and 4

\

B \\

---- --_/

100

c

Above-ground rock 0 - 15 % Terrain units 1 and 3

50

c

100 .

200

300

400

Figure 8 A DECORANA ordination of the vegetation of the high-lying areas of the Ea Land Type in the Villiers - Grootvlei area, South Africa. A, Diospyros lycioides - Eragroslis curvula Shrubland; B, Themeda Iriandra - Trachypogon spicalus Grassland; C, Themeda Iriandra - Cymbopogon plurinodes Grassland.

curvula - Pogonarthria squarrosa Grassland (A) and the other communities (B - E) of the low-lying Ea Land Type can be observed. This separation is mainly associated with geological differences where the Eragrostis curvula Pogonarthria squarrosa Grassland mainly occurs on Aeolian sand and the other communities mainly on sandstone, shale and dolerite. The first two axes of the ordination may be used to illustrate the communities and environment interactions. The first axis explains 76.8% and the second axis 45.3% of the variation in the data set. Although there is no clear separation between communities B, C, D and E (Figure 7), the differences can be ascribed to different veld management practices. In the scatter diagram a distinct separation between the different communities and sub-communities of the highlying Ea Land Type can be observed (Figure 8). The first and second axes of the ordination may be used to explain the plant communities and environment interactions. The first axis explains 73.9% and the second 32.6% of the variation in the data set. The releves of the Diospyros lycioides - Eragrostis curvula Shrubland (A) are separated from the Themeda triandra - Elionurus muticus Grassland (B, C) on the basis of inclination, altitude and geology (Figure 8). The releves of the Themeda triandra - Trachypogon spicatus Grassland (B) are separated from the releves of the Themeda triandra - Cymbopogon plurinodes Grassland (C) on the basis of above-ground rock cover and the position in the landscape (Figure 8).

Conclusion The vegetation of the Ea Land Type occurs in two habitat units, namely the high-lying and the low-lying areas. A total of seven main plant communities and nine sub-communities are classified and described. In terms of the habitat, the subcommunities are not clearly separated, mainly because of the different management practices. This was confirmed by

the DEcORANA ordination. As the plant commumUes are well associated with definite sets of environmental conditions, a degradation regime, they represent sound ecological units. These units should be incorporated in a veld management strategy on regional and farm level, as management units should be homogenous in vegetation and ecology. This classification also contributes to the syntaxonomical synthesis presently being done by the Botany Department of the University of Pretoria.

Acknowledgements Mr. H. Bezuidenhout is thanked for valuable help with the phytosociological tables. The Department of Agricultural Development is thanked for financial support.

References ACOCKS, J.P.H. 1988. Veld Types of South Africa, 3rd ed. Mem . bOI. Surv. S. Afr. 57: 1 - 146. BEZUIDENHOUT, H. 1988. 'n Plantsosiologiese studie van die Mooirivieropvanggebied, Transvaal. M.Sc. thesis, Potchefstroom University for Christian Higher Education, Potchefstroom. BLOEM, KJ. 1988. 'n Plantsosiologiese studie van die Verlorenvalei-natuurreservaat, Transvaal. M.Sc. thesis, University of Pretoria, Pretoria. BRAUN-BLANQUET, J. 1932. Plant sociology: The study of plant communities (translated and edited by G.D. Fuller & H.S . Conrad). McGraw-Hill, New York. BREDENKAMP, GJ. 1975. Plantsosiologiese studie van die Suikerbosrand-Natuurreservaat. M.Sc. thesis, University of Pretoria, Pretoria. BREYTENBACH, PJ.J. 1991. Die fitososiologie van die Villiers - Grootvlei-omgewing. MSc thesis, University of Pretoria, Pretoria. BREYTENBACH, PJJ., MYBURGH, WJ., THERON, G.K., & BREDENKAMP, G.J. 1992. The phytosociology of the Villiers - Grootvlei area, South Africa. 1. Physical environ-

246 ment and the plant communities of the Bb Land Type. S. Afr. J. Bot. 58: 239 - 249. BREITENBACH, P.J.J., MYBURGH, WJ., THERON, G.K. & BREDENKAMP, G.I. 1993a. The phytosociology of the Villiers - Grootvlei area, South Africa 2. The plant communities of the Ba Land Type. S. Afr. J. Bot. 59: 218 - 226. BREITENBACH, P.J.J., MYBURGH, WJ., THERON, G.K . & BREDENKAMP, G.I. 1993b. The phytosociology of the Villiers - Grootvlei area, South Africa 3. The plant communities of the Ib Land Type. S. Afr. J . Bot. 59: 227 - 234. CAIN, S.A. & CASTRO, G.M.deO. 1959. Manual of vegetation analysis. Harper & Brothers, New York. DEALL, G.B. 1985. A plant-ecological study of the Eastern Transvaal escarpment in the Sabie area, Vols. 1 & 2. M.Sc. thesis, University of Pretoria, Pretoria. DEPARTMENT OF AGRICULTURE AND WATER SUPPLY. 1986. Landbou-ontwikkelingsprogram. Hoeveldstreek. Directorate Agricultural Information. Government Printer, Pretoria. DEPARTMENT OF MINERAL AND ENERGY AFFAIRS . 1986. 1:250 000 2628 EAST RAND Geological Map. Geological Survey, Pretoria. EDWARDS, D. 1972. Botanical survey and agriculture. Proc. Grassld. Soc. sth. Afr. 7: 15 - 19. EDWARDS, D. 1979. The role of plant ecology in the development of South Africa. Bothalia 12: 748 - 751. GmBS RUSSELL, G.E., REID, e., VAN ROOYEN, 1. & SMOOK, L. 1985. List of species of southern African plants, 2nd edn., Part 1. Mem. bot. Surv. S. Afr. 51: 1 - 152. GmBS RUSSELL, G.E., WELMAN, W.G., RETIEF, E., IMMELMAN, K.L., GERMISHUIZEN, G., PIENAAR, BJ., VAN WYK, M., NICHOLAS, A., DE WET, C., MOGFORD, I.e. & MULVENNA, I. 1987. List of southern African plants, 2nd edn., Part 2. Mem. bot. Surv. S. Afr. 56: 1 - 270. HILL, M.O. 1979. DECORANA - A FORTRAN Program for

S.-Afr.Tydskr.Plantk., 1993, 59(2) Detrended Correspondence Analysis and Reciprocal Averaging. Cornell University, Inthaca, N.Y. KOOIJ, M.S. 1990. A phytososiological survey of the vegetation of the north-western Orange Free State. M.Sc. thesis, University of Pretoria, Pretoria. LAND TYPE SURVEY STAFF 1984. Land types of the maps 2628 East Rand and 2630 Mbabane. Mem. agric. nat. Resour. S. Afr. No.5. MACVICAR, C.N., DE VILUERS, I.M., LOXTON, R.F., VERSTER, E., LAMBRECHTS, U.N., MERRYWEATHER, F.R., LE ROUX, I., VAN ROOYEN, T.H. & HARMSE, H.I. von M. 1977. Soil classification: A binomial system for South Africa. Department of Agriculture Technical Services, Pretoria. MYBURGH, WJ., BREITENBACH, PJ.I., THERON, G.K. & BREDENKAMP, GJ. 1992. Die fitososiologie van die Bankenveld in die Grootvlei-omgewing, Suid-Transvaal. Bothalia 22: 245 - 254. OOSTING, HJ. 1956. The study of plant communities. W.H. Freeman & Co., San Francisco. TURNER, BJ. 1989. A phytosociological study of the southeastern Transvaal Highveld grasslands. M.Sc. thesis, University of Pretoria, Pretoria. VAN ROOYEN, N. 1978. 'n Ekologiese studie van die plantgemeenskappe van die Punda Malia - Pafuri - Wambiyagebied in die Nasionale Krugerwildtuin. M.Sc. thesis, University of Pretoria, Pretoria. WERGER, M:I.A. 1974. On concepts and techniques applied in the Ziirich-Montpellier method of vegetation survey. Bothalia 11: 309 - 323. WESTFALL, R.H., DEDNAM, G., VAN ROOYEN, N. & THERON, G.K. 1982. PHYT