In southern Africa, White Rhinos are typically associated with drier forms of savanna woodland, with mean annual rainfall under750 mm. In Hluhluwe–iMfolozi Park they favor thornveld dominated by Acacia spp., but in Kruger N. P. they have settled abundantly in broadleaf savanna on granitic soils where Combretum spp. predominate.
They have never been recorded in the treeless grasslands of the Highveld and inland KwaZulu-Natal. Being dependent on water, white rhinos are always close to water, no more than 5km away. The recent range in Garamba N. P. is likewise mostly tall Loudetia/Hyparrhenia grassland on lateritic and granite-derived sandy soils with widely scattered trees of Vitex doniana and Terminalia mollis.
Falling within the Sudano-Guinean Savanna belt, the natural state of this area is tree/bush savanna Combretum/Terminalia woodland, but the southern part of the Garamba is kept like a grassland by frequent intense fires and a high density of elephants. The area is regularly dissected by flowing rivers with patches of gallery forest. A crucial feature of this habitat is the presence of regularly spaced termite glades. They cover 10–12% of the surface area of the grassland, but an average of 42% of all rhino observations over a ten-year period wherein termitaria clearings.
The Loudetia grass is unavailable to the rhinos as a food source above 0.5 m in height, but in the long grass seasons, the termitaria clearings are the site of smaller, more palatable species. The long grass-covered areas are used by rhinos as cover, both for resting during the day and when disturbed, but it is the termite in the tall grass that provides both protection and air circulation.
Black rhinos can be found anywhere where grass and woody chervil are found in sufficient quantities. As a result, black rhinos can survive in a wide range of habitats, including deserts, semi-deserts, wooded savannahs, forests, and also subalpine heaths up to 3700 m on Mount Kenya; occur in areas with mean annual rainfall between 100 mm and 1300.
The latter regions have an annual rainfall of 600 In East Africa, patches of subterranean forest marked by a plateau of Acacia xantophloea and dense forests throughout the year, the underlying layer of grasses and shrubs also supports very high densities of rhinos, such as Lake Nakuru, Kenya and the Lerai forests of the Ngorongoro Crater, although at present forest are more competitive for browsing and nuisance from savannah elephants Loxodonta africana.
In contrast, rhinos are found in low densities in the open habitats of inland East African savannah the Serengeti–Mara ecosystem, where browse availability is very sparse. The black rhino is found in parts of Kenya in the north and in forested areas of the western Serengeti, the lush valley of the bushveld in the Eastern Cape, and Zululand thornveld.
Nutrient poor habitats including broad-leafed miombo woodlands have low carrying capacities. In parts of southern Africa, frost also reduces the carrying capacity of the black rhino. Black Rhino carrying capacities over much of southern Africa are only in the region of 0.1 rhino/km2.
The availability of good and intermediate quality browse is the main factor determining Black Rhino density in a habitat. The speed of growth of navigation also affects the carrying capacity, and it is determined by the annual amounts of rainfall, rainfall seasonality, minimum temperatures, the fertility of the soil, and the resulting plant species composition.
The proportional plant species composition of the available browse and its palatability to the Black Rhino are also important. Black Rhinos are water-dependent in the majority of habitats, and rhino home ranges are arranged relative to permanent water sources in an area. Rhinos can, however, stray far enough from water within reach.
In Etosha N.P., only 1.1% of aerial sightings of black rhinos were more than 14 km from water, in other areas, rhinos prefer to stay within 4-8 km of the water source. However, where sufficient water-containing succulent vegetation occurs, Black Rhinos can survive for several months in the total absence of surface water.