IN THE LAND OF THE
BARRIER OF SPEARS
The Drakensberg Mountains of
South Africa and Lesotho
John and Hilary Birks
The Barrier of Spears
Introduction
Names
Location
Geology and topography
Climate Land-use and fire Vegetation
Botanical Features
State of knowledge
Richness
Endemics
Altitudinal Zonation
Montane belt
Subalpine belt
Alpine belt
The Big Taxonomic Headache – Helichrysum!
Why so Rich?
Conservation and the Future
INTRODUCTION
Names
Barrier of Spears or 'a row of spears pointing upwards' –
Zulu name (Quathlamba or uKhahlamba) for the jagged
spires of the Drakensberg Mountains
Highest mountain of the 'Great Escarpment' in southern
Africa rising to 3000 m, with the highest peak at Thabana
Ntlenyma at 3482 m, the highest mountain in Africa south
of Kilimanjaro (Tanzania).
'Great Escarpment' lies parallel to the south-eastern
coast of South Africa from the Eastern Cape extending
into Zimbabwe. Separates southern Africa from the
interior plateau.
Great Escarpment initiated during the break-up of
Gondwanaland.
Called Drakensberg ('dragon mountain') by early
Dutch settlers (Voortrekkers) because of its
resemblance to the ridges of a dragon's back.
Steep ridges of its dragon-like back are formed by
headwater erosion of rivers that separate the
Highveld Plateau from the coastal lowlands of
southern Africa.
Less likely, the name may be derived from an
insignificant peak called Drakensberg or Dragon's
Rock.
Part of KwaZulu-Natal of South Africa and Lesotho
(= Mountain Kingdom, Basutoland).
Cathkin Peak
The Sentinel
The Sentinel
The Amphitheatre
Location
28º30' – 31º20'S,
27º00' – 29º40'E
About 40 000 km2
1800 – 3482 m
Drakensberg Alpine Centre or Region
Geology and topography
Much of the area lies on the high plateau above 3000
m of Lesotho bounded by the Drakensberg escarpment
to the east, north, and south extending into South
Africa.
Mostly formed of basalt lavas, up to 1400 m thick and
forming sheer cliffs up to 460 m high.
Underlain by Clarens sandstone (up to 2500 m), often
undercut with caves with many Bushman paintings.
1. North Drakensberg from near Rhodes
2. North Drakensberg and Amphitheatre
3. Clarens Sandstone, Royal Natal National Park
4. North Drakensberg and Devil's Tooth
5. Maletsunyre Waterfall, Lesotho
Thought to be some of the oldest mountains in
the world. In centre of continent rather than at
edges of continents.
At edge of the interior plateau of southern Africa.
With break-up of Gondwanaland about 200 million
years ago, lavas flowed through fissures and
capped the sedimentary sandstones for about 50
million years from early Jurassic to the
Cretaceous.
Soils are thin on the basalt plateau; almost nonexistent on the escarpment; deep on the Clarens
sandstone.
Soil pH about 5.5 – 6.0, very deficient in N and P,
high levels of exchangeable Al.
Summit soils become wet and water-logged in
summer. In winter subject to freezing at night
and thawing by day.
Ice-heaved stones, stone polygons, solifluction
terraces, frost hummocks (thurfur) on the high
plateau.
6. Sani Top Flats, 2900 m
7. Black Mountain, 3100 m
Climate
Main feature is summer rainfall
Temperate climate with summer rainfall.
Mean temperature of warmest month at 3050 m
ca. 10.9ºC.
Mean annual rainfall 635 mm in west to 2000 mm
on main plateau. Diminishes in the east due to the
rain-shadow effect.
Alpine belt (above 2750 m) is severe with a mean
annual temperature of 5.7ºC. Highest recorded is
31ºC (January 1972), coldest -20.4ºC (June 1967).
Half year, minimum temperatures are below 0ºC.
Snow cover – four months or longer in protected
gullies or south-facing slopes.
Frost daily in winter.
Mist common throughout year.
Summit winds important. Very high winds in spring
and summer, especially in afternoons and evenings.
Summer heavy thunderstorms characteristic.
3050 m altitude
(1) Precipitation exceeds temperature: climate is 'humid'
(2) Winter has low rainfall and low temperatures
Temperature chart for
3050 m altitude
Mean annual
temperature = 5.7ºC;
183 days with frost
Land-use and Fire
Fire is dominant ecological factor
1. Natural caused by lightning usually in spring or when
boulders roll down and collide with other boulders to
produce sparks that ignite dry grass swards.
2. Bushmen burning to produce new grass growth that
would attract game for hunting.
Bantu and European farmers burnt grasslands to provide
winter grazing for sheep and cattle.
Natural lightning ground-flash density of 12 - 14 flashes per
km2 per year.
Alpine areas burnt by Lesotho people on fairly
regular annual basis.
Summer grazing by cattle, horses, sheep, and goats.
Extreme overstocking of grazing animals in Lesotho
(300% overstocking).
Severe soil erosion and inwashing of silt.
Large areas in Lesotho flooded to provide Lesotho
Highlands Water Project for South Africa. Value
about $38 million per year by 2030.
Natal Drakensberg produces water worth about
$929 million per year for South Africa.
8.
Maletsunyre Gorge and Fields, 2400 m
9.
Lesotho Huts, Semonkang, 2100m
10. Lesotho Horsemen
11. Lesotho Horsemen and pack ponies
12. Basuto Village
13. Village chiefs
14. Hilary and (other!) chiefs
15. Musicians
16. Semonkong 'hotel' hut
Vegetation
Biomes of southern Africa – all in 'grassland' biome
In Afromontane
and Afroalpine
phytogeographical
region
Montane belt
1280 – 1830 m
Podocarpus latifolius forest
Subalpine belt
1830 – 2750 m
Fynbos (= species-rich heath); now mainly grassland
Alpine belt
2750 – 3484 m
Erica – Helichrysum 'tundra' heath and grasslands
Debate about what is the 'alpine belt'.
Defined climatically rather than floristically at 2750 –
2865 m elevation.
Called Afroalpine region, whereas lower levels above
1800 m are Afromontane region.
No real change, gradual floristic changes, but there
is the big escarpment in the way!
Extent of alpine belt above 2750 m
BOTANICAL FEATURES
State of Knowledge, Richness, and Endemics
About 2200 species, 4 endemic genera, 400 endemic
species (ca. 18%)
Largest families
1. Asteraceae
5. Cyperaceae
2. Scrophulariaceae
6. Orchidaceae
3. Poaceae
7. Ericaceae
4. Iridaceae
Helichrysum (85)
Argyrolobium (18)
(Fabaceae)
Senecio (76)
Moraea (16)
(Iridaceae)
Erica (25)
Thesium (15)
Disa (24)
(Orchidaceae)
Hypoxis (15)
(Hypoxidaceae)
Selago (19)
(Scrophulariaceae)
Kniphofia (15)
(Liliaceae)
Crassula (19)
Life-study of Olive Hilliard and Bill Burtt, now retired
but still very active at Royal Botanic Gardens Edinburgh.
September
2003
Visited Drakensberg with Alpine Garden Society 5 – 20
January 2002 with David McDonald and John
Grimshaw.
Saw about 700 species – richest area we have visited!
Great show of colourful bulbous plants, orchids, and
composites.
Has strong affinities with the Cape Floristic Region
as well as the Afromontane Region.
Weak links with the Afroalpine Region of East
Africa.
88 genera in Drakensberg have their centres of
diversity in the Cape Floristic Region (e.g. Erica,
Protea, Helichrysum).
ALTITUDINAL ZONATION
Montane Belt
1280 – 1830 m (lowest visited 1750 m)
Podocarpus latifolius forest
Protea savannah
Grassland – C4 grasses (? result of fire)
Cliffs and rock outcrops
17.
Royal Natal National Park Podocarpus forest, 1750 m
18.
Thamocalamus tesselatus
19.
Peperomia retusa
20.
Zantedeschia albomaculata
21.
Carex zulensis
22.
Begonia sutherlandii
23.
Impatiens hochstetteri – Old World Tropics
24.
Steptocarpus gardenii
Gesneriaceae
25.
Stenoglottis fimbriata
Orchidaceae
26.
Pteris cretica
27.
Gleichenia umbraculifer S. Hemisphere
28.
Adiantum poiretii
29.
Elaphoglossum drakensbergensis – tropical America, 400 spp
30.
Harveya speciosa Parasitic Scrophulariaceae
bamboo
Piperaceae
Arum lily
Araceae
16 species
200 or 1 spp
Africa
31. Golden Gate and scrub, 1895 m
32.
Protea roupelliae
33.
Cyathea dregei
34.
Agapanthus campanulatus Liliaceae
35.
Agapanthus campanulatus
36.
Gladiolus crassifolia
37.
Berkheya rapontica
38.
Leonotis leonuris Labiatae 40 spp. Africa
39.
Phygelius capensis 2 spp.
40.
Zaluzianskya microsiphon
41.
Sopubia cana
42.
Striga bilobata
43.
Scilla nervosa
10 spp.
S. Africa
75 spp. S. Africa
40 spp. Africa
50 spp. Africa, Himalaya, Formosa, Vietnam
Hemiparasite, 40 spp.
40 spp.
Africa, Asia, Australia
44.
Ophioglossum polyphyllum
45.
Drosera natalensis
46.
Brunsvigia radulosa
47.
Waterfall, Royal Natal National Park, 18450 m
48.
Gladiolus microcarpus
49.
Hilary and Galtonia regalis
50.
Galtonia viridflora
51.
Royal Natal National Park sandstone cliffs, 1800 m
52.
Asplenium aethiopicum
53.
Cheilanthes multifida
54.
Crassula umbraticola
55.
Crassula pellucida ssp. brachypetala
125 spp. 18 in SA, mainly NZ or Australia
Africa, 20 spp. Amaryllidaceae
150 spp. 100 in S. Africa
4 spp. Liliaceae
300 spp. 280 in S. Africa
Subalpine Belt
1830 – 2750 m
Protea savannah
Grassland – C4 grasses (? result of fire)
Mires, flushes. and 'sponge' bogs
Cliffs and rock outcrops
56.
Oxbow, Lesotho
2500 m
57.
Protea roupelliae 115 spp. 80 in S. Africa, W Cape
58.
Protea dracomontana
59.
Protea subvestita
60.
Dioscorea sylvatica Dioscoreaveae 600 spp. semi-tropical,
20 in SA
61.
Crassula sarocaulis
62.
Bowkeria verticillata
63.
Erica drakensbergensis 650 spp. 600 in SA (Cape)
64.
Dierama dracomontanum
65.
Dieranam robustum
66.
Naude's Nek 2400 m
67.
Moraea alticola
68.
Moraea alpina
69.
Sandersonia aurantiaca
70.
Gladiolus longicollis
Shrub Scrophulariaceae
75 spp. Africa Iridaceae
90 spp. 75 in S. Africa
Liliaceae
Christmas Bells
71.
Hesperantha grandiflora
60 spp. Iridaceae
72.
Watsonia densiflora
73.
Watsonia pillandsi
74.
Androcymbium striatum
75.
Croscosmia pearsii
76.
Dianthus basuticus
77.
Naude's Nek Cliffs 2550 m
78.
Nerine bowdenii
79.
Ranunculus baurii
80.
Kniphofia ritualis
81.
Kniphofia triangularis
82.
Craterocapsa congesta 4 spp.
83.
Wahlenbergia cuspidata
84.
Chironia perglerae
85.
Cephalaria oblongifolia
86.
Harpachloa falix
70 spp.
S Africa
Iridaceae
30 spp. 3 in Mediterranean
Iridaceae Endemic 9 spp.
22 spp. S Africa only
70 spp. 45 in S Africa
Amaryllidaceae
Liliaceae
S Africa
200 spp. mainly S Africa
Gentianaceae
30 spp.
Africa
Dipsaceae Mediterranean, Asia, Cape
Caterpillar Grass
Monotypic
87.
Hypoxis rigidula
Hypoxidaceae
100 spp. 50 in S Africa
88.
Xerophyta viscida Velloziaceae
89.
Geranium multisectum
90.
Monsonia brevirostrata
91.
Pelargonium alchemilloides
92.
Lotononis sericophylla
93.
Lotononis pulchra
94.
Sutherlandia montana
6 spp.
95.
Pachycaprus dealbatus
Ascelepiadaceae
96.
Pachycarpus campanulatus
97.
Selago cf. flanaganii
98.
Jamesbrittenia pristisepala
99.
Diascia vigilis
Africa, Arabia
28 spp.
Geraniaceae 25 spp. Africa
250 spp. S Africa
100 spp.
Africa, India
S Africa
50 spp. 24 in S Africa
50 spp. 24 in S Africa
150 spp.
S Africa
83 spp. 74 S Africa
30 spp. S Africa
100. Cycnium racemosum
40 spp.
Africa
Hemi-parasite
101. Alectra capensis Hemi-parasite 40 spp. S America, Asia, 10 in SA
102. Harveya leucopharynx
Parasite
40 spp. 25 in S Africa
103. Rhodes – Naude's Nek 2400 m
104. Berkheya cirsiifolia
105. Berkheya purpurea
106. Haplocarpha scaposa
107. Inulanthera calva
8 spp. Africa
10 spp. Africa
108. Senecio macrospermus
2000 spp. 350 in S Africa
109. Senecio isatidens
110. Senecio gramineus
111. Senecio macrocephalus
112. Senecio polyodon
113. Naude's Nek grassland 2800 m
114. Hirpicum armerioides
115. Gazania krebsiana
12 spp.
16 spp.
116. Pterygodium magnum
Africa
S Africa
14 spp.
80 in area
117. Corycium nigrescens
15 spp.
118. Satyrium neglectum
100 spp.
119. Schizochilus flexuosus
120. Holothrix scopularia
121. Disa nervosa
10 spp.
35 spp.
130 spp.
Africa
122. Disa stachyoides
123. Disa crassicornis
124. Disa thodei
125. Disa fragrans
126. Disa versicolor
127. Eucomis autumnalis
10 spp.
Africa
Liliaceae
128. Eucomis bicolor
129. Eucomis bicolor
130. Eucomis schiffii
131. Bulbine capitata
35 spp. mainly Cape
132. Meadow near Semonkong
2200 m
133. Pharcocapnos pruinosus
134. Argemone ochroleuca
135. Papaver aculeatum
Fumariaceae
3 spp. Africa
Papaveraceae
100 spp. 1 in Africa
136. Kniphofia caulescens
Liliaceae
137. Kniphofia caulescens
138. Kniphofia caulescens
sun-birds
139. Carex cognata
140. Cyperus spaerocephalus
600 spp.
50 in Africa
141. Sponge bogs, Black Mountain 2800 m
142. Eriocaulon dregei var. sonderiana
400 spp. 12 in Africa
143. Anagallis huttonii
30 spp. 2 in S Africa
144. Utricularia livida
30 spp. 15 in S Africa
145. Crassula papillosa
146. Limosella major
18 spp. 6 in S Africa
147. Gunnera perpensa
148. Sani Cliffs 1900 m
Gunneraceae
50 spp.
1 in S Africa
149. Cotyledon orbiculata var. oblongata
150. Aloe aristata
Liliaceae
Crassulacea 40 spp.
Africa
300 spp. 145 in S Africa
151. Aloe polyphylla
152. Aloe polyphylla
153. Euphorbia clavarioides
2000 spp.
200 in A Africa
154. Erica reenensis
155. Steptocarpus pusillus
156. Holothrix incurva
Orchidaceae
157. Hemanthus humilis ssp. hirsutus
158. Cyrtanthus epiphyticus
159. Sebaea natalensis
Amaryllidaceae
100 spp. 45 in S Africa
160. Polystichum monticola
161. Ceterach cordatum
162. Cheilanthes hirta
163. Dryopteris athamantica
164. Mohria hirsuta
Amaryllidaceae 21 spp. SA
Schizaeaceae
50 spp.
Africa
Gentianaceae
Alpine Belt
2750 – 3484 m
Alpine heath 'tundra'
Alpine grassland and summit areas
Mires and flushes
Aquatic and stream-side communities
Cliffs
165. Ben MacDhui 3001 m
166. Black Mountain, Lesotho
3220 m
167. Macowania sororis
11 spp. 9 in Eastern S Africa
168. Euryops montanus
98 spp.
S Africa
169. Euryops tysonii
170. Chrysocoma tenuifolia
18 spp. 12 in S Africa
171. Erica frigida
172. Helichrysum marginatum
173. Helichrysum milfordiae
174. Sentinel Plateau 3010 m
175. Albuca humilis
75 spp. mainly S Africa
176. Crassula natalensis
177. Massonia cf. echinata
Liliaceae
178. Lotononis galpinii
179. Jamesbrittenia jurassica
180. Selago galpinii
181. Sutera breviflora
130 spp. Africa
1 in Canary Isles
182. Diascia fetcaninesis
183. Luzula africana
80 spp. 1 in S Africa
184. Cerastium capense
60 spp. 5 in S Africa
185. Polygala gracilenta
600 spp. 100 in S Africa
186. Alchemilla natalensis
187. Hesperantha radiata
250 spp. 20 in S Africa
Iridaceae
60 spp Africa
188. Asclepias humilis
189. Aster eruciformis
190. Felicia rosulata
250 spp. few in S Africa
80 spp. mainly S Africa
191. Delosperma congesta
Mesembryanthemaceae
140 spp.
192. Delosperma lineare
193. Romulea thodei
Iridaceae
194. Manulea parviflora
Scophulariacea 60 spp. S Africa
195. Sentinel Summit 3010 m
196. Kniphofia fluviatilis
90 spp. 70 in S Africa
197. Sentinel Summit pools 3000 m
198. Juncus dregeanus
300 spp. 25 in S Africa
199. Cotula lineariloba
90 spp. 40 in s Africa
200. Alepidea woodii
Umbelliferae 25 spp. all S Africa
201. Wurmbea elatior
202. Lobelia erinus
Liliaceae 25 spp. Africa and Australia
Campanulaceae
203. Rhodohypoxis baurii var. baurii
300 spp. 70 in S Africa
Hypoxidaceae 6 spp. SA only
204. Rhodohypoxis baurii var. confecta
205. Crassula drakensbergensis
206. Isolepis fluitans
40 spp. 30 in S Africa
207. Aponogeton junceum Aponogetonaceae 25 spp. Africa, Asia,
Australia 5 in S Afric
208. Lagarosiphon muscoides Hydrocharitaceae 16 spp. 5 in S Africa
209. Sani Top 3100 m
210. Ben MacDhui 3001 m
212. Devil's Tooth, Sentinel
213. Teguela Falls
214. Steel ladders, Sentinel Escarpment
215. Gladiolus flanaganii
216. Euryops evansii
217. Woodsia montevidensis 40 spp. 1 in S Africa
218. Diascia cordata
219. Diascia stricta
220. Nemesia rupicola
70 spp Africa
221. Crassula setulosa var. curta
222. Glumicalyx goseloides 6 spp. Drakensberg only
223. Tiffendall Ski Resort
224. Sani Pass Transport
225. Sani Chalet
2900 m
2873 m
THE BIG TAXONOMIC HEADACHE –
HELICHRYSUM!
Mainly African genus, some in Mediterranean Europe,
SW Asia, S India, Sri Lanka, Australia
 600 species, 245 in South Africa, 85 in Drakensberg,
found 60
Herbs, climbers, low shrubs
Grasslands, woodland, scrub, cliffs, screes, windblasted open grassland, rock outcrops, mesic areas
226.
Helichrysum montanum
237. H. aureoniteus
227.
H. marginatum
238. H. aureum
228.
H. milfordiae
239. H. albo-aureum
229.
H. pagophilum
240. H. herbaceum
230.
H. vernum
241. H. flanaganii
231.
H. bellidiastrum
242. H. panduratum
232.
H. tenuifolium
243. H. acutatum
233.
H. witbergense
244. H. krokii
234.
H. trilineatum
245. H. hypoleucum – climber
235.
H. ecklonis
246. H. drakensbergense
236.
H. confertiflium
247. Hilary and H. montanum
WHY SO RICH?
Drakensberg is an international 'hot-spot' of plant
biodiversity, not only of vascular plants (2200 species)
but also of bryophytes (over 1000 species).
Nothing known about vegetational history.
Endemics (18%) are mixture of palaeo-endemics and
neo-endemics.
Some major disjunctions (e.g. Macowania – Drakensberg,
Ethiopia, Yemen; Thamnocalamus – Drakensberg, east
Asia).
Small area ca. 40 000 km2 ( Belgium)
Possible contributory factors for high diversity
1. Centuries of low-intensity ('intermediate') disturbance
from Bush-people.
2. Soils are infertile but not strongly acid and high in Al.
3. Mixture of floristic elements (Cape, Afromontane, etc.)
4. Altitudinal range of over 2000 m.
5. Climatic gradients within 1500 m from alpine periglacial
features to lush Podocarpus forest with Streptocarpus.
6. Topographical diversification into distinct valleys and
watersheds, favouring isolation of species.
7. Fine-scale topographical variation with springs, flushes,
soaks, mires, etc. within well-drained grassland.
CONSERVATION AND THE FUTURE
3% in Lesotho and 97% in Natal Drakensberg are protected
as Nature Reserves, National Parks, and Wilderness Areas.
Major threats by overstocking and soil erosion in Lesotho.
Also threats from invasive exotic plants and clearance for
crops in an area very poorly suited to arable agriculture in
Lesotho.
At present alpine areas (nearly all in Lesotho) are
unprotected.
Urgent need for whole areas as Biosphere Reserve or
World Heritage Site.
But conservation is not the major problem facing southern
Africa……
Besides problems of overstocking, soil erosion, and
hydroelectric development in Lesotho, major threat
is from 'global warming'.
McDonald et al.
(2002) defined
climate
envelopes for 16
alpine species
today, to define
the modern
'alpine' climate.
Predicted the extent of the 'alpine' climate under
future scenario of IPCC for 2150.
See major reduction in 'alpine' climate, confined
to the few highest areas. Would become very
fragmented. Major loss of species.
Much reduced snow cover, loss of available
water. Major ecological and economic effects.
248. David MacDonald and John Grimshaw
249. Amphitheatre, Witsishoek 04:30 hours
Thanks
John Grimshaw
Bill Burtt
David McDonald
Olive Hilliard
Else Pooley
Cathy Jenks