Limpopo Levubu Floodplains: Nyala, Buffalo, Waterbuck, Impala, Elephant Bulls
Location and Geomorphology
As the name indicates, this landscape occurs on the banks of the Limpopo and Levubu Rivers. The underlying material of this area is alluvium that has been deposited over the years on the floodplains along the rivers. This is a low lying landscape with a flat to concave topography. The altitude varies between 200 and 250 metres.
When the Limpopo and Levubu Rivers are both in flood, a blockage takes place above the confluence and because the area is flat, and sometimes concave, flooding of the land adjacent to the rivers takes place. Silt is deposited and pans that normally hold water for a long period such as the Gwalala, Rietbok, Nyala, Nwambi, Hulukulu, Makwadzi, Spokenyolo and Dakamila pans, are filled. This pan veld is a unique characteristic of this landscape while koppies do not occur.
Purely from a rainfall point of view, this is one of the driest landscapes in the KNP, with an annual average of 438 mm at Pafuri. Moisture is more available in these parts due to the flooding of the river banks. Temperatures are extremely high during summer, but there is no weather station situated near enough to record the temperature variations.
The soils of this landscape are alluvial and the material thus probably originates from granite, Waterberg Sandstone, Cave Sandstone, basalt, dolerite as well as other parent rock formations. Expected soil Forms are Inhoek, Dundee and Oakleaf on the floodplains, with Arcadia and Willowbrook soils in the pans.
Van Rooyen (1978) describes the following components of this landscape:
1. Colophospermum mopane/Acacia tortilis/Urochloa mosambecensis-tree savanna.
2. Acacia albida/Ficus sycomorus-river forest.
3. Acacia xanthophloea/Panicum meyerianum-open tree savanna.
4. Sporobolus consimilis-grass veld.
The Colophospermum mopane/Acacia tortilis/Urochloa mosambicensis-tree savanna (Fig. 62) occurs on the basalt footslopes. Dominant woody species associated with Colophospermum mopane and Acacia tortilis are Maerua parvifolia, Grewia bicolor, Azima tetracantha, Acacia Senegal var. rostrata, Salvadora angustifolia, Hyphaene natalensis, Commiphora glandulosa, Thilachium africanum, Ximenia Americana, Gardenia resiniflua, Maytenus heterophylla, Dalbergia melanoxylon, Acacia nigrescens, Gardenia spatulifolia, Zanthoxylum humilis, Boscia albitrunca and Adansonia digitata. Almost homogeneous stands of baobab occur in certain localities. The field layer is sparse with a large variety of species.
Fig. 62. Landscape 28. Colophospermum mopane/Acacia tortilis/Urochloa mosambicensis tree savanna. – page 96
Grass species are Tragus berteronianus, Aristida congesta subsp. barbicollis, Chloris virgata,Sporobolus smutsii, Enneapogon cenchroides and Dactyloctenium aegypteum. Forbs are Alternanthera pungens, Trianthema trigquetra, Cyathula crispa, Corbichonia decumbens. Pupalia lappacea, Hibiscus micranthus, H. engleri, Indigofera rhytidocarpa, Boerhaavia difuusa, Ecbolium revolutum, Gisekia africana and Ipomoea obscura. The Acacia albida/Ficus sycomorus-river forest (Fig. 63) occurs on the banks of the rivers and consists of a large variety of species. Van Rooyen (1978) gives a complete species list, but only a few of the most important species are mentioned here. The community is a closed forest of about 20 metres high. Dense undergrowth with little grass occurs. The most important woody species are: Acacia albida, Ficus sycomorus, Acacia robusta, Trichilia emetica, Xanthocercis zambesiaca, Acacia ataxacantha, Ficus capreifolia, Combretum microphyllum, Grewia caffra, Diospyros mespiliformis, Tabernaemontana elegans, Acacia xanthophloea, Lonchocarpus capassa, Combretum imberbe, Acacia tortilis, Kigelia africana, Maclura africana, Albizia harveyi, Rauvolfia caffra, Ekebergia capensis, Strychnos potatorum, Breonadia microcephala, Syzygium guineense, Deinbollia oblongifolia, Ochna confuse, Nuxia oppositifolia, Azima tetracantha, Mimusops zeyheri, Garcinia livingstonei, Croton megalobotrys, Hyphaene natalensis and Ficus stuhlmanii.
The field layer of this community is sparse and the following species are important: Abutilon angulatum, Achyranthes aspera, Epaltes gariepina, Hypoetes verticillaris, Hibiscus engleri, Wissadula rostrata, Ageratum conyzoides, Cynanchum schistoglossum. The grass cover is sparse and consists of species such as Panicum meyerianum, Urochloa mosambicensis, Echinochloa pyramidalis, Chloris gayana, Cymosetaria sagittifolia and Sporobolus consimilis.
Fig. 63. Landscape 28. Acacia albida/Ficus sycomorus river forest. – page 97
The Acacia xanthophloea/Panicum meyerianum-open savanna (Fig. 64) is found in the floodplains. It is a tree veld from between six to 15 metres high and consists of the following species: Acacia xanthoploea, Combretum imberbe, Dichrostachys cinerea subsp. africana, Securinega virosa, Combretum mossambicense, Lonchocarpus capassa, Combretum hereroense, Croton megalobotrys, Xanthocercis zambesiaca, Kigelia africana, hyphaene natalensis, Spirostachys africana and Maytenus senegalensis.
The above-mentioned community continues into a Sporobolus consimilis- grass veld (Fig. 65) with the disappearance of the woody component to leave an open grass veld. A grass height of two can be reached and the dominant species are: Sporobolus consimils, Setaria sphacelata, Panicum meyerianum, P. deustrum, Ischaemum afrum, Panicum maximum, Chloris gayana, Cenchrus ciliaris, Echinochloa pyramidalis, Phragmites australis and Sorghum verticilliflorum. Forbs that occur occasionally are: Achyranthes aspera, Abutilon guineense and Corchorus kirkii.
The communities occurring in and around the pans consist mainly of the following species: Sporobolus consimilis, Panicum meyerianum, Echinochloa pyramidalis, Ischaemum afrum, Setaria sphacelata, Cyperus fastigiatus, C. corymbosus, C. sexangularis, C. immensus, C. articulatus, C. distans and Nymphaea caerulea.
This landscape accommodates the largest population of nyalas in the KNP. Other species of game that are abundant on these floodplains are bushbuck, duiker, buffalo, kudu, waterbuck, impala and elephant bulls. Baboons and vervet monkeys (Cercopithecua pygerythrus) are plentiful and recently Samango monkeys (Cercopithecus albogularis) were reintroduced. Hippo and crocodile (Crocodylus niloticus) are common in the water. This landscape also represents the only confirmed habitat of bushpigs (Potamochoerus porcus) in the KNP. This landscape is a paradise for birds, with its dense, high trees and water pans and Newman (1980) gives a complete list of the birds to be found here.