Lebombo North: Crested Guinea Fowl, Pumbe Sandveld North to Shingwedzi River
Location and Geomorphology
This landscape is the extention of Landscape 29 on the rhyolites of the Lebombo Mountains. There is, never the less, good motivation as to why it is classified as a separate landscape, as will be seen from the descriptions of the climate and vegetation composition. This area extends from Pumbe sandveld northwards to the Shingwedzi River with Singomeni as a detached unit further north. The Lebombo Mountains are intersected west/east by deep incisions of the Olifants and
Fig. 68. Landscape 30. Pumbe Sandveld – page 104
Fig. 69. Landscape 30. Pumbe Pan with pebble-bed. – page 104
Shingwedzi Rivers. This part of the landscape just north of the Olifants River, is drained south and south-west by a number of spruits of which the Mkhadzi, Mhalamhala, Msimbitsane, Masaka and Marhandzala are the most important drainage channels. The Lebombo Mountains in this area are situated between 300 and 400 metres a.s.l. and are strongly undulating with dense bushy ravines. This landscape covers 480 km/2 or 2.9 percent of the area of the KNP.
Climate and more specifically rainfall, is the most important reason why the Lebombo range has been divided into two landscapes. The rainfall in the northern part of the Lebombo Mountains varies between 450 and 500 mm annually. The occurrence of fog in the vicinity of the river gorges in the Lebombo Mountains contributes extensively to the availability of moisture to plants in this area. The temperature is high in summer with the absence of frost in winter. Temperature data from Letaba (Table 6) are applicable to this landscape.
The soils of this landscape are shallow and rocky and in most cases it cannot be classified as soil. Up to 80 percent of the surface can be covered with stones and rocks.
The vegetation of this landscape is very similar to that of the Lebombo South (Landscape 29) except that it is slightly drier (Fig. 70). The vegetation is consequently less mesic and the following species are present:
Fig. 70. Landscape 31. Lebombo North. – page 105.
Combretum apiculatum, Commiphora mollis, Kirkia acuminate, Euphorbia confinalis, E. cooperi, Ximenia caffra, Grewia flavescens, G. bicolor, G. hexamita, Cassia abbreviate, Tricalysia allenii, Boscia albitrunca, Croton gratissimus, Rhus gueinzii, Adenia spinosa. Rhoicissus revoilii, Phyllanthus reticulates, Capparis tomentosa, Gardenia resiniflua, Elehantorrhiza burkei, Cissus rotundifolius, Strychnos decussate, Pavetta schumanniana, Lannea stuhlmannii, Sclerocarya caffra, Combretum mossambicense and Ficus soldanella. The drier habitat of this landscape provides ideal habitat for trees such as Adansonia digitata and Androstachys johnsonii and they occur frequently on the slopes and in the ravines. Other rare species that occur sporadically are listed in Landscape 29.
The field layer on the Lebombo Mountains is naturally sparse, considering that 80 percent and more of the soil surface is covered with rock. Dominant grasses are Panicum maximum, Digitaria eriantha var. pentzii, Heteropogon contortus, Enneapogon cenchroides and Aristida congesta subsp. barbicollis. Forbs that occur regularly are Barleria affinis, Tragia dioica, Heliotropium steudneri and Cardiospermum halicacabum.
A characteristic attribute of this landscape is the occurrence of dense thickets of Androstachys johnsonii (Fig. 71), especially in the vicinity of the Olifants River valley. Coetzee (1983), Van Rooyen (1978) and Van Wyk (1973) provide descriptions of the composition of this bush. It is a dense forest community with closed canopies and is completely dominated by Androstachys johnsonii. Other species that occur are Euphorbia confinalis, Phyllanthus reticulates, Entandrophragma caudatum, Strophanthus kombe, Croton pseudopulchellus, Hymenodictyon parvifolium and Boscia albitrunca. The field layer is usually very sparse to absent and the following species may be present: Aristida congesta subsp. barbicollis, Cymbosetaria sagittifolia, Brachiaria xantholeuca, Cyperus rupestris and Selaginells dregei.
Fig. 71. Landscape 31. Androstachys johnsonii bush on the Lebombo Mountains. – page 106
Van Rooyen (1978) describes Androstachys johnsonii bush in the Punda Maria area, and according to him the following woody species can be associated with the above-mentioned: Pouzolzia hypoleuca, Euphorbia espinosa, Dombeya kirkii, Monodora junodii, Vitex amboniensis, Alchornea laxiflora, Cassia abbreviata and Combretum apiculatum. The following species occur in the field layer: Sporobolus panicoides, Enteropogon macrostachyus, Setaria ustilata, Leptocarydion vulpiastrum, Cymbosetaria sagittifolia, Danthoniopsis pruinosa, Panicum heterostachyum, Pseudobrachiaria deflexa, Achryanthes sicula, Celosia trigyna, Selaginella dregei, Cleome monophylla, Corchorus longipedunculatus, Blainvillea gayana, Xerophyta equisetoides and X. humilis. It would appear that the Androstachys johnsonii bush at Punda Maria is more mesic than that of the Lebombo Mountains.
A characteristic of both these variations of the Androstachys johnsonii bush is the occurrence of the lichen, Usnea poliotrix. Under normal circumstances this climate would be too dry for this lichen and it can therefore be speculated that moisture, other than that coming from rain, plays a role in the occurrence of U. poliotrix as well as the Androstachys johnsonii bush. The regular occurrence of fog can perhaps play a role ( Coetzee 1983). All areas where this plant community occurs are subject to regular fog and moisture may possibly be adsorbed by the system in this manner.
Kudu are the most important large mammal moving about in the Lebombo Mountains. Buffalo, impala, zebra, waterbuck and warthog occur regularly but in smaller numbers. Sharpe’s grysbok, duikers and bushbuck occur in the dense ravines and in the Androstachys johnsonni bush. Giraffe is also present in this area. Elephant breeding herds occur regularly in the Lebombo Mountains just north and south of the Olifants River valley. Nyalas may be found along the lower Letaba and Mkhadzi and eland are sometimes seen in the vicinity of Longwe. The most important habitat foe sable antelope has probably been fenced off by the boundary fence, but a small herd occurs along the Kalabyene spruit.
According to Newman (1980), the crested guinea fowl (Guttera edouardi) occurs in small numbers on the northern Lebombo Mountains, especially in the dense Androstachys johnsonii bush.