The site consists of the Waterberg range and its cliffs. The range is about 150 km long and it runs from 15 km north-east of Thabazimbi, eastwards, to Hanglip Point c.30 km west of Potgietersrus. The Kransberg, a massif within the western sector of the Waterberg range, has been incorporated into Marakele National Park. The region is surrounded by granite, basalt and sandstone ridges, which are eroded into natural blocks by the Mogol and Lephalala rivers.The area is characterized by open broadleaved woodland that is common on the plains below the Waterberg mountains, dominated by trees of Faurea, Terminalia, Acacia, Burkea and Peltophorum in the deep sandy areas, with Kirkia and Englerophytum characteristic on the rocky slopes. Other trees scattered throughout various communities include species of Heteropyxis, Dombeya, Lannea and Pterocarpus. Natural climax grassland is scarce and it occurs only in the highest regions where it is restricted to the highest plateaus or cool south-facing slopes. On deep sands, where termitaria occur, typical bushveld clumps become common. Proteoid shrubland occurs on cool slopes. Forest and thicket communities develop in the kloofs and ravines, holding trees of Podocarpus, Mimusops, Combretum, Olea, Calodendrum, Ficus, Diospyros, Maytenus and other forest elements.
See Box for key species. Kransberg holds the largest Gyps coprotheres colony in the world; it comprised c.900 breeding pairs in 1984, but by 1998 numbers had fallen to c.700 pairs. Most of the vulture cliffs are situated outside Marakele National Park, which should be enlarged to incorporate the key breeding cliffs. The Kransberg also holds breeding Ciconia nigra. The grasslands support small populations of Neotis denhami and Eupodotis senegalensis. Promerops gurneyi occurs at higher altitudes where Protea roupelliae dominates the proteoid shrubland. The woodland at the base of the mountains holds Bucorvus cafer and Ardeotis kori, which breed near Ellisras, and are regular within the IBA. Other woodland birds include Eupodotis ruficrista, Mirafra passerina, Bradornis mariquensis, Lamprotornis australis, Cercotrichas paena, Calamonastes fasciolatus, Laniarius atrococcineus, Vidua regia and Eurocephalus anguitimens.
Non-bird biodiversity: The threatened butterfly, Eriksonia acraeina, occurs here. The global ranges of the cycad Encephalartos eugene-maraisii, and the reptiles Lygodactylus waterbergensis, Cordylus breyeri and Platysaurus minor, are virtually restricted to these mountains. Both Platysaurus guttatus and P. relictus (LR/nt) have global ranges restricted to the Waterberg and nearby Soutpansberg (IBA ZA002). The mammal Loxodonta africana (EN) has been reintroduced in various high-profile conservation areas.
Pressure/threats to key biodiversity
Within the Waterberg system, the Kransberg in the west is protected in Marakele National Park (44,000 ha) and the adjoining Welgevonden Private Nature Reserve (14,000 ha). Ironically, most of the vulture breeding cliffs fall outside the protected areas; reserve boundaries should be reconsidered in order to include these. Strychnine poisonings (from surrounding farmland) have been recorded regularly, and pose a major threat to vultures that feed on poisoned carcasses set for vermin. Hundreds of vultures can be killed in a single irresponsible poisoning incident. A vulture-awareness campaign for farmers may help reduce poisonings. Disturbance by recreational mountaineers has been shown to greatly reduce hatching success and has been recognized as a major source of mortality to both eggs and young. Collisions with radio and television towers have also caused substantial vulture mortality.