2. 2. Study area
Loskop Dam Nature Reserve is situated in Mpumalanga province,
approximately 55 km North of Middelburg in the Olifants River valley
at latitude 25°22′ to 25°31′ South, and 29°10′ to 29°24′ East (Fig. 1).
The Nooitgedacht section covers approximately 4457 ha and is located
on the northwestern boundary of the reserve (Fig. 1).
LDNR occurs in the summer rainfall region of South Africa and has
warm to very hot summers with moderate winters. Rainfall occurs
mainly as showers and high intensity thunderstorms, often accompa-
nied by severe lightning and strong, gusty, southwesterly winds. The
majority of rainfall occurs during the hot summer months (November
to April). The mean long-term rainfall (2004 to 2014) for LDNR is
650 mm per annum. Rainfall and temperature data for the study period
(2010 to 2012) were collected at a weather station located at the
reserve's main office (Fig. 2).
The Nooitgedacht section occurs on the higher lying areas of the
reserve and resembles typical grassland vegetation. Soils are predomi-
nantly shallow interspersed with prominent rocky outcrops, while
deeper soils occur in lower lying areas. Land types describe the different
soil and climate patterns for an area (Fitzpatrick et al., 1986). Mucina
and Rutherford (2006) defined a land type as a map unit that can be
mapped at 1:250,000 scale. Land types identified in the study area in-
clude Fa7, Ib17, Ib10, and Ib13. Fa7 and Ib10 land types occur on shallow
soils with underlying hard rock or fractured and weathering rock
material; lime is rare or absent (Land Type Survey Staff, 1988). Ib10
Fig. 1. Location of the study area in Loskop Dam Nature Reserve, Mpumalanga.
Fig. 2. Rainfall and temperature data for the study period.
80 S.E. Nkosi et al. / South African Journal of Botany 105 (2016) 79–88
3. and Ib13 land types have in excess of 60% rock cover and occur on
shallow soils (Land Type Survey Staff, 1988).
3. Materials and methods
The Braun–Blanquet approach to vegetation classification and
description was used for this study. Homogenous vegetation units
were delineated using a series of 1:50,000 stereo aerial photographs. A
total of 170 sample plots were identified and placed in a randomly
stratified manner in delineated vegetation units (Bezuidenhout, 1993;
Brown and Bredenkamp, 1994). Additional sample plots were placed
in larger vegetation units to ensure sufficient sampling (Brown et al.,
2013). GPS coordinates of all sample plots were recorded. Predetermined
sample plot sizes (100 m2
) were used based on surveys done in Savanna
vegetation (Weger, 1974; Coetzee, 1975; Bezuidenhout, 1993). Data
were collected over two growing seasons from November 2010 to
April 2012.
3.1. Data collection
Using a modified Braun–Blanquet cover abundance scale, species
presence and percentage cover of the different vegetation layers
(trees, shrubs, and herbaceous) were recorded (Mueller-Dombois and
Ellenberg, 1974). The number of woody plants in three different height
classes (Lower 0–1 m, Medium N1–3 m and Upper N3 m) was also re-
corded (Brown and Bredenkamp, 1994). Environmental and related
variables collected included plot location (GPS coordinates); plot num-
ber; accessibility of the area to wildlife (signs of grazing, browsing,
trampling, droppings, paths); signs of fire (current and previous);
slope (flat 0°–3°, gentle 3.1°–9°, moderate 9.1°–15°, steep 15.1°–25°,
and very steep 25.1°–55°) (Westfall, 1981); altitude (metres above sea
level); and aspect (north, northeast, east, southeast, south, southwest,
west, and northwest).
Total tree density (TTD) within each sample plot was determined by
counting the number of trees per species present. Trees and shrubs
were distinguished from one another using the guidelines set by
Edwards (1983).
3.2. Data analysis
Floristic and habitat data were captured using TURBOVEG
(Hennekens, 1996). All relevé data were exported as a Cornell Con-
densed species file into JUICE 7.0 (Tichy, 2002) for editing, classifying,
and analysing floristic data into a preliminary phytosociological table.
A modified TWINSPAN (Hill, 1979; Rolecěk et al., 2009) classification
was performed using Whittaker's beta-diversity to derive a first approx-
imation of the plant communities for the study area. Pseudo-species cut
levels were set at 0–1-5-25-55-75, and the phytosociological table was
manually refined according to Braun–Blanquet procedures (Brown
et al., 2013). A vegetation map of the classified plant communities
was produced using ArcGIS 10 (ESRI, 2014).
Tree density (ind/ha) was calculated for each plant community per
height class using the following formula:
Tree density ¼
Total number of trees per plant community  10; 000 m2
À Á
Total size of sample plots for plant community
Data collected using the Braun–Blanquet cover abundance scale
(Table 1) were transformed from an alpha-numeric scale to a numerical
scale (‘r’ = 1,’1’ = 2, ‘+’ = 3, ‘2a’ = 5, ‘2b’ = 6, ‘3’ = 7, ‘4’ = 8, ‘5’ = 9)
to calculate species diversity (H) and evenness (E) for the different plant
communities (Van der Maarel, 1979). Shannon–Wiener diversity
indices were determined and compared using H and E (Shannon and
Wiener, 1963).
4. Results
4.1. Vegetation classification
A modified TWINSPAN classification resulted in the identification of
eleven plant communities grouped into seven major communities and
presented in Table 1 (Fig. 3):
1. Sporobolus africanus–Buddleja salviifolia wetland
2. Panicum maximum–Senegalia caffra riverine woodland
Fig. 3. Vegetation map of the Nooitgedacht section.
81S.E. Nkosi et al. / South African Journal of Botany 105 (2016) 79–88
6. 2.1 Panicum maximum–Senegalia caffra–Olea europaea subspecies
africana sub-community
2.2 Panicum maximum–Senegalia caffra–Searsia leptodictya sub-
community
3. Eragrostis curvula–Hyparrhenia hirta old field grassland
4. Setaria sphacelata–Lannea discolor open woodland
4.1 Setaria sphacelata–Lannea discolor–Englerophytum magalismontanum
sub-community
4.2 Setaria sphacelata–Lannea discolor–Senegalia burkei sub-community
5. Pygmaeothamnus zeyheri–Rhoicissus tridentata rocky shrubland
6. Tristachya leucothrix–Faurea saligna open woodland
7. Elionurus muticus–Loudetia simplex open grassland
7.1 Elionurus muticus–Loudetia simplex–Tristachya biseriata sub-
community
7.2 Elionurus muticus–Loudetia simplex–Aristida diffusa sub-community
7.3 Elionurus muticus–Loudetia simplex–Gladiolus elliottii sub-community
4.2. Plant community descriptions
4.2.1. Sporobolus africanus–Buddleja salviifolia wetland
This plant community covers approximately 58 ha (1.3%) of the
study area (Fig. 3). It occurs within seasonally wet drainage channels
and seepage lines on the southwestern side of the study area. Patches
are also present in the eastern and central sections and on the central
western boundary. Altitude varies between 1285 and 1406 m above
sea level (m.a.s.l.). Slopes of 0°–9° characterise this area and are accessi-
ble to animals. This plant community is associated with the Ib10 and
Ib17 land types, which are characterised by shallow clay loam to clay
soils (Land Type Survey Staff, 1988).
Estimated tree cover varies between 0% and 5%, shrubs between 10%
and 60%, grasses between 20% and 65%, and forbs between 10% and 50%.
Rocks cover between 5% and 10% of the community. Animal activity is
high, with signs of animal droppings, evidence of moderate grazing,
and relatively high trampling. Moderate erosion is visible near an
artificial dam found in this community.
Characteristic species for this community are from species group A
(Table 1). Five sample plots represent this community with an average
of 27 different plant species recorded per plot. Vegetation is dominated
by the shrub Buddleja salviifolia (species group A) and the grass
Sporobolus africanus (species group A). This community has a total
tree density of 620 ind/ha with no individuals taller than 3 m. The
shrub Buddleja salviifolia has 180 ind/ha in the medium height class,
and 120 ind/ha in the lower height class. The prominent woody species
Diospyros lycioides (species group A) has 80 ind/ha in the medium
height class, and 40 ind/ha in the lower height class (Table 2).
4.2.2. Panicum maximum–Senegalia caffra riverine woodland
This community is scattered throughout the study area, covering ap-
proximately 526 ha (11.8%) of the study area (Fig. 3). Altitude ranges
from 1206 to 1310 m.a.s.l. The structure of this community varies
from open to closed woodland with rocky outcrops and gentle slopes
with a gradient of 4°–9°. This community is located in the Ib10 land
type characterised by shallow sandy loam to sandy clay loamsoils
(Land Type Survey Staff, 1988).
Estimated tree cover for this woodland varies between 20% and 90%,
shrub cover between 10% and 70%, grass cover between 5% and 60%, and
forb cover between 5% and 50%. Rocks cover between 10% and 55%. Ero-
sion is visible along game paths, and there are indications of previous
fire damage in the area.
Species belonging to species group B (Table 1) are characteristic for
this plant community. Vegetation is dominated by the tree Senegalia
caffra and the grass Panicum maximum (species group B). Other locally
prominent species include the trees Ziziphus mucronata, Celtis africana,
Heteropyxis natalensis (species group B), Senegalia burkei, Dombeya
rotundifolia, Searsia leptodictya, Albizia harveyi, Searsia pyroides (species
group D), and the grass Setaria sphacelata (species group R). This
community is divided into two sub-communities:
4.2.2.1. Panicum maximum–Senegalia caffra–Olea europaea subspecies
africana sub-community. This sub-community covers approximately
55 ha and is located on the north and northeastern side of the study
area (Fig. 3). Altitude ranges from 1206 to 1310 m.a.s.l. The area com-
prises gentle north and south facing midslopes with gradients ranging
between 4° and 9°. Signs of animal tracks, mild grazing, and trampling
are visible in this sub-community.
Species from species group C (Table 1) are characteristic for this sub-
community. Four sample plots represent this sub-community, with an
average of 36 different plant species recorded per plot. The herbaceous
layer is not well developed due to high woody cover, and vegetation is
dominated by the trees Senegalia caffra and Olea europaea subspecies
africana (species group B). The grass Panicum maximum (species
group B) is present under trees throughout this sub-community. A
total tree density of 1450 ind/ha was recorded. The tree Senegalia caffra
(species group B) has a tree density of 75 ind/ha in the upper height
class and 100 ind/ha in the medium height class. Olea europaea subspe-
cies africana (species group B) has 50 ind/ha in the upper height class,
25 ind/ha in the medium height class, and 50 ind/ha in the lower height
class (Table 2).
4.2.2.2. Panicum maximum–Senegalia caffra–Searsia leptodictya sub-
community. This sub-community is located in the central part of the
study area, with patches present in the northern, northeastern, south-
ern, and southwestern sections (Fig. 3). It covers approximately
471 ha. Altitude ranges from 1272 to 1382 m.a.s.l. The habitat is accessi-
ble to wildlife and occurs on gentle north and south facing midslopes
with gradients of 4° to 9°.
Characteristic species for this sub-community are from species
group D (Table 1). Fifteen sample plots were surveyed for this sub-
community, with an average of 33 different plant species recorded per
plot. The vegetation is dominated by the trees Senegalia caffra (Species
group B), Searsia leptodictya (species group D), and the grass Panicum
maximum (species group B). This sub-community has a total tree densi-
ty of 1036 ind/ha. Searsia leptodictya has 33 ind/ha in the upper height
class, 47 ind/ha in the medium height class, and 7 ind/ha in the lower
height class. Senegalia caffra has 87 ind/ha in the upper height class
and 33 ind/ha in the medium height class, and Maytenus alba has
50 ind/ha in the upper height class and 25 ind/ha in the medium height
class (Table 2).
4.2.3. Eragrostis curvula–Hyparrhenia hirta old field grassland
This community covers approximately 252 ha (5.7%) of the study
area and is located on the central, western, and southwestern borders
of the study area (Fig. 3). Altitude ranges from 1272 to 1450 m.a.s.l.
Gentle north facing slopes with a gradient of 0°–9° occur in the area.
This community is located in the Fa7 land type, characterised by well-
drained shallow sandy loam to sandy clay loamsoils on hard rock
(Land Type Survey Staff, 1988).
Estimated tree cover varies between 0% and 5%. One sample plot is
located on a rocky outcrop and comprises 20% tree cover. Shrubs
cover between 2% and 10% of this community, grasses between 50%
and 90%, and forbs between 10% and 20%. Rocks cover between 5%
and 10%. Evidence of previous crop planting, regular fires, and animal
activity (moderate to high grazing and trampling) is prevalent in this
community. Local people from the surrounding community harvest
thatch grass. There are no signs of soil erosion.
Species from species group E (Table 1) are characteristic for this
community and are represented by 15 sample plots with an average
of 30 different plant species recorded per plot. The anthropogenic
grass Hyparrhenia hirta (species group Q) dominates this community.
Other prominent grass species include Sporobolus africanus (species
group A), Cynodon dactylon, Eragrostis curvula, Aristida congesta
84 S.E. Nkosi et al. / South African Journal of Botany 105 (2016) 79–88
7. subspecies congesta (species group E), Brachiaria brizantha (species
group J), Schizachyrium sanguineum (species group Q), and Melinis
nerviglumis (species group R). This community has a total tree density
of 256 ind/ha. Trees occur as small clumps on rocky outcrops not previ-
ously ploughed. Tree species include Ziziphus mucronata (species
group K) with 20 ind/ha in the upper height class and 7 ind/ha in the
lower height class, and Searsia leptodictya (species group D) with
13 ind/ha in the upper height class and 0 ind/ha in the lower height
class (Table 2).
4.2.4. Setaria sphacelata–Lannea discolor open woodland
This community is located on the northeastern, central, southern,
and southeastern sections of the study area, covering approximately
393 ha (8.8%) (Fig. 3). Altitude ranges from 1217 to 1391 m.a.s.l. Slopes
range from gentle north, northwest, and southeast facing midslopes
(4°–9°) to moderately steep slopes (10°–15°). Predominant land types
for this community are Fa7, Ib10, Ib13, and Ib17. These land types are
characterised by loam, sandy loam, and sandy clay loam soils (Land
Type Survey Staff, 1988).
Estimated tree cover varies between 30% and 70%, shrubs between
10% and 50%, grasses between 10% and 60%, and forbs between 10%
and 60%. Rocks cover between 30% and 50% and occur as prominent
rocky outcrops. Soil erosion is minimal; however, mild localised sheet
erosion is visible on disturbed rocky areas, along animal paths, and at
destroyed termitariums. Signs of frequent fires are prevalent through-
out the area, with evidence of dead Dichrostachys cinerea trees.
Species from species group F (Table 1) are characteristic for this plant
community. Vegetation in this community is characterised by the domi-
nance of the tree Lannea discolor (species group F) and the grass Setaria
sphacelata (species group R). Other locally prominent species include
the woody Englerophytum magalismontanum, Combretum molle, Burkea
africana, Combretum apiculatum (species group F); the grass Andropogon
chinensis (species group F); and the forb Phymaspermum acerosum
(species group F). This community is divided into two sub-communities:
4.2.4.1. Setaria sphacelata–Lannea discolor–Englerophytum magalismon-
tanum sub-community. This sub-community is located on the south-
western section of the study area and covers approximately 148 ha
(Fig. 3). Altitude ranges from 1329 to 1391 m.a.s.l. and comprises gentle
to steep southeast and northwest facing slopes of 4°–25°. Steeper rocky
slopes in this sub-community are inaccessible to animals. Soils range
from sandy loam to sandy clay loam (Land Type Survey Staff, 1988).
Characteristic species for this sub-community are from species
group G (Table 1). Ten sample plots were surveyed with an average of
35 different plant species recorded per plot. This sub-community is
dominated by the trees Lannea discolor, Englerophytum magalismon-
tanum (species group F), and the grasses Loudetia simplex (species
group Q) and Setaria sphacelata (species group R). This sub-
community has a total tree density of 1130 ind/ha with Lannea discolor
having 90 ind/ha in the upper height class and 70 ind/ha in the medium
height class, Englerophytum magalismontanum has 40 ind/ha in the upper
height class, 40 ind/ha in the medium height class, and 10 ind/ha in
the lower height class. The locally prominent tree Diplorhynchus
condylocarpon is represented by 70 ind/ha in the upper height class
and 80 ind/ha in the medium height class (Table 2).
4.2.4.2. Setaria sphacelata–Lannea discolor–Senegalia burkei sub-
community. This sub-community is located on the northeastern and
southern parts of the study area and is nearly twice the size of sub-
community 4.1, covering approximately 245 ha (Fig. 3). Altitude ranges
from 1217 to 1357 m.a.s.l. This sub-community is characterised by gen-
tle north, northwest, and southeast facing midslopes with a gradient of
4°–9°. The midslopes are accessible to animals, while steep slopes with
gradients of 16°–25° provide limited animal access. Soils range from
loam to sandy loam. The area is covered with loose rocks between 10
and 50 cm in diameter.
Plant species from species group H (Table 1) are characteristic
for this sub-community. Twelve sample plots represent this sub-
community with an average of 39 plant species recorded per plot. This
sub-community has a total tree density of 1340 ind/ha. Vegetation is
dominated by the trees Senegalia burkei with 92 ind/ha in the upper
height class, 58 ind/ha in the medium height class, and 75 ind/ha in
the lower height class (species group D), Lannea discolor with 75 ind/ha
in the upper height class, 50 ind/ha in the medium height class, and
75 ind/ha in the lower height class (species group F) (Tables 1 and 2).
The grass layer is dominated by the grasses Setaria sphacelata and
Themeda triandra (species group R).
4.2.5. Pygmaeothamnus zeyheri–Rhoicissus tridentata rocky shrubland
This plant community occurs as open shrub habitats on the south-
eastern side of the study area; patches on the northern, eastern, central,
and southeastern borders of the study area and on the southwestern
sections of the study area (Fig. 3). It covers approximately 141 ha
(3.7%) and occurs at an altitude ranging between 1325 and
1430 m.a.s.l. This shrubland comprises gentle (4°–9°) to moderately
steep (10°–15°) south and southwest facing midslopes. Predominant
land types in this community include Ib10, Ib13, and Ib17. Soils vary
from fine sandy loam and sandy loam to sandy clay loam (Land Type
Survey Staff, 1988).
Estimated tree cover varies between 30% and 60%, shrub cover
between 10% and 40%, grass cover between 10% and 50%, and forb
cover between 10% and 40%. Rock cover ranges from 20% to 45%. Mini-
mal signs of soil erosion were observed. There are indications of animal
activity in the form of moderate grazing, game paths, and trampling.
Evidence of previous fires is prevalent throughout the area.
Characteristic plant species for this community are from species
group I (Table 1). A total of 18 sample plots represent this community
with an average of 41 different plant species recorded per plot. This com-
munity has a total tree density of 828 ind/ha. The vegetation of this com-
munity is characterised by the prominent sprawling shrub Rhoicissus
tridentata (species group B), the dwarf shrub Pygmaeothamnus zeyheri
(species group I), and the grasses Setaria sphacelata (species group
R) and Loudetia simplex (species group Q). Rhoicissus tridentata (species
group B) has 11 ind/ha in the medium height class and 28 ind/ha in
the lower height class. Additional prominent woody species include Cro-
ton gratissimus with 28 ind/ha in the upper height class and 11 ind/ha in
the medium height class, and Combretum molle with 22 ind/ha in the
upper height class, 11 ind/ha in the medium height class, and 6 ind/ha
in the lower height class (Table 2).
4.2.6. Tristachya leucothrix–Faurea saligna open woodland
This community occurs on the northern section of the study area,
covering approximately 708 ha (15.9%) of the study area (Fig. 3). Alti-
tude ranges from 1251 to 1441 m.a.s.l. Slopes range from flat (0°–3°)
to gentle (4°–9°) on south facing midslopes. Land types associated
with this plant community include Fa7 and Ib10. This woodland is
characterised by fine sandy loam to sandy clay loam soils (Land Type
Survey Staff, 1988).
Estimated tree cover varies between 25% and 45%, shrub cover
between 10% and 40%, grass cover between 30% and 70%, and forbs
between 10% and 50%. Rocks cover between 10% and 40% of this com-
munity. Soil erosion is minimal due to a well-developed herbaceous
layer. Evidence of frequent fires is prevalent in the form of dying stands
of Dichrostachys cinerea trees. Mild to moderate trampling is present
and there is evidence of digging by small mammals.
Species from species group K (Table 1) are characteristic for this
community. A total of 19 sample plots were surveyed with an average
of 40 different plant species recorded per plot. Vegetation in this com-
munity is characterised by the dominance of the tree Faurea saligna
(species group K), and by the grasses Tristachya leucothrix and Brachiaria
serrata (species group Q). The grasses Trachypogon spicatus, Panicum
natalense (species group P), and Loudetia simplex (species group
85S.E. Nkosi et al. / South African Journal of Botany 105 (2016) 79–88
8. Q) codominate. Other locally prominent species include Dichrostachys
cinerea, Ozoroa paniculosa, Lippia javanica (species group K), and
Protea caffra (species group O). This community has a total tree density
of 902 ind/ha. Faurea saligna has 42 ind/ha in the upper height class,
53 ind/ha in the medium height class, and 279 ind/ha in the lower
height class. Dichrostachys cinerea has 21 ind/ha in the upper height
class, 58 ind/ha in the medium height class, 79 ind/ha in the lower
height class, and Protea caffra has 47 ind/ha in the upper height class,
5 ind/ha in the medium height class, and 5 ind/ha in the lower height
class (Table 2).
4.2.7. Elionurus muticus–Loudetia simplex open grassland
This is the largest community in the study area and covers approxi-
mately 2379 ha (53.4%). It occurs on the central and southern sections of
the study area (Fig. 3). Altitude ranges from 1318 to 1455 m.a.s.l.
Slopes vary from flat plateau/crests (0°–3°) to gentle (4°–9°) and
steep (16°–25°) south, north, and east facing slopes. Prevalent land
types include Fa7, Ib10, Ib13, and Ib17. Soils range from fine sandy
loam to sandy clay loam (Land Type Survey Staff, 1988).
Estimated tree cover varies between 5% and 40%, shrubs between 5%
and 30%, grasses between 30% and 80%, and forbs between 5% and 40%.
Rock cover ranges from 5% to 40%, with loose rocks prominent on
slopes. There is evidence of recent fire damage that destroyed several
Protea caffra trees in sub-community 7.3. Signs of animal activity include
low to moderate grazing and trampling in recently burnt areas, digging,
and animal droppings.
Species belonging to species group L are characteristic for this com-
munity (Table 1). Vegetation in this community is dominated by the
grasses Loudetia simplex (species group Q) and Bewsia biflora (species
group R), while Themeda triandra (species group R) and Urelytrum
agropyroides (species group P) are prominent throughout the commu-
nity. The woody layer is not well developed with small scattered clumps
of locally prominent Protea caffra (species group O) trees. This grassland
community is divided into three sub-communities:
4.2.7.1. Elionurus muticus–Loudetia simplex–Tristachya biseriata
sub-community. This sub-community is located on the southern and
southwestern borders of the study area and covers approximately
202 ha (Fig. 3). Altitude ranges from 1318 to 1466 m.a.s.l. Slopes
range from flat (0°–3°) to gentle (4°–9°) south facing midslopes. The
area is accessible to animals and there is evidence of grazing in recently
burnt areas, trampling, and digging. Soils are shallow fine sandy to
sandy clay loam. The grass layer is well developed, and minimal soil
erosion is present.
This sub-community has no characteristic species group and is
characterised by the absence of species from species groups O and P
(Table 1). A total of 11 sample plots represent the sub-community,
with an average of 34 different plant species per plot. This sub-
community has a total tree density of 153 ind/ha. The vegetation is
dominated by the grasses Loudetia simplex, Tristachya biseriata (species
group Q), Themeda triandra, and Bewsia biflora (species group R). Prom-
inent species include the grasses Brachiaria serrata (species group
Q) and Eragrostis racemosa (species group R), and the woody species
Protea caffra with 18 ind/ha in the upper height class, and 27 ind/ha in
the lower height class, Faurea saligna with 0 ind/ha in the upper,
0 ind/ha in the medium and 36 ind/ha in the lower height classes, and
Tapiphyllum parvifolium with 9 ind/ha in the medium height class and
18 ind/ha in the lower height class (Table 2).
4.2.7.2. Elionurus muticu–Loudetia simplex–Aristida diffusa sub-
community. This sub-community is located in the south and northeast-
ern section of the study area and covers approximately 926 ha (Fig. 3).
Altitude ranges from 1316 to 1440 m.a.s.l. Slopes vary from flat
plateau/crests (0°–3°) to gentle (4°–9°) north facing midslopes and
steep south facing slopes (16°–25°). Flat and gentle areas are accessible
to wildlife and evidence of animal activity includes grazing, trampling,
digging, and fresh animal droppings. Soil varies from fine sandy loam
to sandy clay loam, with minimal evidence of soil erosion (Land Type
Survey Staff, 1988).
This sub-community is characterised by species found in species
group M (Table 1). A total of 22 sample plots represent this sub-
community with an average of 36 different plant species per plot. This
sub-community has a total tree density of 217 ind/ha. The vegetation
is dominated by the grass Loudetia simplex (species group Q), with the
grasses Themeda triandra, Eragrostis racemosa (species group R),
Tristachya biseriata, Brachiaria serrata (species group Q), and Aristida
diffusa (species group M) being locally prominent. Prominent woody
species include Strychnos cocculoides with 5 ind/ha in the lower, medi-
um, and upper height classes; Lopholaena coriifolia with 14 ind/ha in
the medium and lower height classes; Protea caffra with 3 ind/ha in
the upper height class; and Mundulea sericea with 5 ind/ha in the
medium height class and 14 ind/ha in the lower height class (Table 2).
4.2.7.3. Elionurus muticus–Loudetia simplex–Gladiolus elliottii sub-
community. This sub-community is located centrally in the study area
and covers approximately 1251 ha (Fig. 3). Altitude ranges from 1370
to 1455 m.a.s.l. Slopes vary from flat plateaus with a gradient of 0°–3°
to gentle midslopes of 4°–9° that are accessible to wildlife. There is
evidence of moderate grazing and trampling throughout the sub-
community. Soil consists of fine sandy loam to sandy clay loam with
very little evidence of erosion.
Characteristic species for this sub-community are from species
group N (Table 1). A total of 39 sample plots were surveyed for this
sub-community with an average of 36 different plant species recorded
per plot. This sub-community has a total tree density of 121 ind/ha.
The vegetation of this sub-community is dominated by the grasses
Bewsia biflora and Eragrostis racemosa (species group R). Loudetia
simplex, Schizachyrium sanguineum, Digitaria monodactyla (species
group Q), and Hyparrhenia hirta (species group R) codominate. The
prominent woody species in this sub-community is Protea caffra with
46 ind/ha in the upper height class and 3 ind/ha in the lower height
class (Table 2).
Table 3
Species richness, frequency distribution, deviation, and evenness for the Nooitgedacht plant communities.
Community N Species richness/observed Expected frequency Percentage deviation Standardised residuals Sum of all n/N * In(n/N) H Evenness (E)
1 109 14 13.32 2.79 0.1 −2.541 2.541 0.963
2.1 112 20 13.32 46.84 1.73 −2.685 2.685 0.896
2.2 186 18 13.32 32.16 1.19 −2.187 2.187 0.757
3 204 21 13.32 54.19 2 −2.499 2.499 0.821
4.1 96 11 13.32 −19.24 −0.71 −2.098 2.098 0.875
4.2 42 7 13.32 −48.6 −1.79 −1.052 1.052 0.541
5 200 20 13.32 46.84 1.73 −4.286 4.286 1.431
6 287 20 13.32 46.84 1.73 −4.955 4.955 1.654
7.2 155 12 13.32 −11.89 −0.44 −2.769 2.769 1.114
7.3 167 14 13.32 2.79 0.1 −2.357 2.357 0.893
86 S.E. Nkosi et al. / South African Journal of Botany 105 (2016) 79–88
9. 4.3. Species richness
The numbers of different plant species present in the Nooitgedacht
plant communities are depicted in Table 3 (based on data in Table 1).
4.4. Species diversity
Results from the Shannon–Wiener Diversity Index analysis are
presented in Table 3.
5. Discussion
In this study, 11 plant communities were identified within four
structural vegetation units: grasslands, shrublands, woodlands, and
wetlands/riverine areas. Grasslands are the dominant vegetation in
the study area, covering 2631 ha (59%). Woodland vegetation covers
1101 ha (25%), wetlands/riverine vegetation covers 584 ha (13%), and
shrublands covers 141 ha (3%). Nooitgedacht is a very diverse area
and comprises 649 species (64% of the reserve's 1016 taxa). One
hundred and ninety-four new species that are not listed for the reserve
occur in the area.
Nooitgedacht is representative of a distributed mosaic grassland and
woodland habitat, referred to as Bankenveld and described as a ‘False
Grass’ veld type (Acocks, 1988; Brown and Bredenkamp, 2003). The cli-
max stage of this veld type should be open Savanna (Acocks, 1988);
however, it has been modified and maintained by regular fires
and grazed as a grassland (Bredenkamp et al., 2006). Bankenveld is
characterised by a complex topography that comprises rocky hills,
ridges, plateaux, valleys, and plains, which are typical of the study
area. Bankenveld areas are also characterised by the presence of rocks
on the soil surface (Brown and Bredenkamp, 2003).
Grassland communities within the study area that have an affinity to
Bankenveld vegetation types, as described by Brown and Bredenkamp
(2003), include plant community 3 that is similar to the Hyparrhenia
hirta anthropogenic grassland (Bankenveld vegetation type 1), and
plant community 7 that is similar to the Monocymbium ceresiiforme–
Loudetia simplex grassland (Bankenveld vegetation type 7). Woodland
community 2 is similar to the Themeda triandra–Vachellia karroo
microphyllous woodland (Bankenveld bushveld vegetation type 11),
woodland community 4 is similar to Ochna pulchra–Englerophytum
magalismontanum warm temperate mountain bushveld (Bankenveld
bushveld vegetation type 10), and woodland community 6 is similar
to Tristachya biseriata–Protea caffra cool temperate mountain bushveld
(Bankenveld bushveld vegetation types 9) (Brown and Bredenkamp,
2003).
Plant communities 1 and 2 (Sporobolus africanus–Buddleja salviifolia
wetland and Panicum maximum–Senegalia caffra riverine woodland) are
ecologically sensitive ecosystems. Wetlands and riverine habitats in the
study area are important due to the multitude of ecosystem services
they provide, including flood attenuation, water storage and channel-
ling, provision of suitable habitat for a variety of plants and animals,
and provision of water to surrounding ecosystems during drought
(Brand, et al., 2011). Although moderate levels of soil erosion were ob-
served, it is important that the reserve management monitor and man-
age this erosion to prevent future problems, especially during times of
drought when animals concentrate in moist areas, overgrazing and
trampling the vegetation.
Woody plant density totals for Nooitgedacht are below the accepted
threshold of 1800 ind/ha for mixed bushveld (Brown, 1997). It is impor-
tant that this density threshold is not exceeded, as this will result in the
rapid loss of veld condition. It is recommended that regular monitoring
be undertaken to ensure woody species densities remain below
1800 ind/ha, and that should numbers increase above this, appropriate
management action be taken. Sub-communities 2.1, 2.2, 4.1, and 4.2
have the highest woody densities (Table 2), and are typical of bushveld
vegetation. Height of woody species is normally distributed for sub-
community 2.2 and community 4, with the majority of woody species
in the medium height class. Sub-community 2.1 has the largest number
of species within the upper height class. Plant communities with the
highest densities of woody species (in excess of 1000 ind/ha) include
sub-communities 2.1, 2.2, 4.1, and 4.2. Plant communities 1, 5, and 6
have woody species densities that range between 600 and 900 ind/ha.
The lowest woody species densities recorded for study area are for
plant community 3 and sub-communities 7.1, 7.2, and 7.3 (grassland
communities) (Table 2). None of the communities in the study area
have woody species densities that have a negative influence on veld
condition. No woody species dominates the vegetation in the study
area and there is no bush densification or encroachment.
The majority of woody species found in grassland communities at
the study site have an aggregated spatial distribution. Woody species
in woodland communities are more evenly distributed. Woody species
in the lower height classes occur close to their ‘mother’ plants. Overall
woody species densities for the study area are normal and indicate
that the area is well managed. There are no indications of bush en-
croachment and the habitat is suitable for browsers and herbivores
that prefer longer grasses for grazing and hiding their young.
For Nooitgedacht, average species diversity per sample plot is 35.
Plant communities 5 and 6 and sub-community 2.1 have the highest
species diversity (n = 20), followed by sub-community 2.2 (n = 18).
Species diversity for plant community 1 and sub-community 7.3 are
the same (n = 14) (Table 3). There was a significant association be-
tween species richness values and communities surveyed x2
(13) =
3.154, P b 0.001. Based on standardised residuals, plant communities 5
and 6 and sub-community 2.1 are over represented (+1.7), and the
main contributors to the association. The association between the
Shannon–Wiener Diversity Index value (H) for the surveyed plant
communities was not significant x2
(13) = 0.000, P = 1.000. Plant com-
munity 5 had an H value of 4.286, and plant community 6 had an H value
of 4.955. These results indicate increased diversity for communities 5
and 6. Plant community 6 (E 1.654) has the most even distribution of
species followed by plant community 5 (E 1.431) and sub-community
7.2 (E 1.114) (Table 3).
From the 11 identified plant communities in the study area, four
plant communities (3, 6 and sub-communities 2.2 and 4.1) were previ-
ously described by different researchers (Theron, 1973; Bezuidenhout
et al., 1994; Cilliers et al., 1999; Filmalter, 2010). Seven plant communi-
ties (1, 5 and sub-communities 2.1, 4.2, 7.1, 7.2, and 7.3) are considered
new plant communities and have not previously been described for the
reserve.
Plant communities 2 and 5 and sub-community 4.2 have affinities
with each other due to the presence of common species from species
group B. The grass Panicum maximum, characteristic of woody habitats
(Van Oudtshoorn, 2012), and the tree Ziziphus mucronata are prominent
in these plant communities. Sub-communities 2.2 and 4.2 have a strong
relationship in terms of their woody component, with the tree Senegalia
burkei (species group D) being prominent in both sub-communities,
however, sub-community 2.2 is wetter than 4.2.
The different land types present in the area are associated with the
different plant communities. The open grassland areas are mostly
associated with the Fa land type, while the woodland and wetland
areas are associated with the Ib land type.
6. Conclusion
Prior to this research, limited information existed for the flora of the
Nooitgedacht section of the LDNR. This study provides valuable infor-
mation on the plant communities occurring in the study area, indicating
affinities in vegetation structure and composition with typical sourish
mixed bushveld and Bankenveld. Similarities are evident in open grass-
lands with scattered trees, and semi-open woodlands on hillsides.
The recently acquired Nooitgedacht section provides both new
habitats and increases the size of existing habitats for browsers, grazers,
87S.E. Nkosi et al. / South African Journal of Botany 105 (2016) 79–88
10. and mixed feeders. This area is suitable for the endangered Sable
antelope (Hippotragus niger) and the reserve's priority species, Oribi
(Ourebia ourebia). Currently, the reserve maintains a stocking rate of
11–12 ha/AU, which includes Nooitgedacht. All fences between the
new area and the main reserve have been removed. We recommend
that the current fire regime for the reserve be applied to the new area
to ensure moribund plant material is removed on a regular basis, and
to create a mosaic of habitats. We further recommend the adoption of
a patch mosaic burning approach for the area, as this creates ideal
habitat for Oribi.
The critically endangered and specially protected plant Encephalartos
middelburgensis (Mpumalanga Province, 2005) and a rare plant
Harworthia koelmaniorum var. mcmurtryi (Biko'o et al., 2011) occur
within the study area. It is important that these species and their
habitats are protected to ensure their survival and to increase their
population sizes. We recommend that these species and their habi-
tats be monitored on a regular basis to prevent loss of habitat.
Four communities (3 and 6, and sub-communities 2.2 and 4.1) of the
11 identified plant communities for the study area have previously been
described for the reserve by Theron (1973). Seven are new plant com-
munities (1 and 5, and sub-communities 2.1, 4.2, 7.1, 7.2, and 7.3) not
previously identified or described. The addition of new plant communi-
ties provides new habitats, new opportunities, and new resources for
existing and potentially new animal species. The increase in sizes of
existing plant communities enlarges the size of the habitats these pro-
vide, increasing resources and allowing for an increase in the sizes of
existing animal populations.
Successful application of the popular Braun–Blanquet classification
system resulted in the achievement of our objectives for this study.
We identified and described the floristic composition of the various
plant communities at Nooitgedacht, classified the plant communities
based on species dominance, and mapped the plant communities. An
association between land types and plant communities for the study
area has been observed, indicating the importance of using land types
in plant community delineation. Our results indicate that the vegetation
for the Nooitgedacht section is well managed and in a natural state with
minimal degradation. The findings generated by this study could be
used to supplement existing management objectives for the reserve.
Supplementary data to this article can be found online at http://dx.
doi.org/10.1016/j.sajb.2016.02.199.
Acknowledgements
We would like to thank the staff and management of MTPA, particu-
larly the staff at LDNR, for making this research possible.
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