Waterberg Biosphere
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The Waterberg Biosphere is a massif of approximately 15,000 square kilometers in north Limpopo Province, South Africa. Waterberg is the first region in the northern part of South Africa to be named as a Biosphere Reserve by UNESCO. The extensive rock formation was shaped by hundreds of millions of years of riverine erosion to yield diverse bluff and butte landform[1]. The ecosystem can be characterised as a dry deciduous forest or Bushveld. Within the Waterberg there are archaeological finds dating to the Stone Age, and nearby are early evolutionary finds related to the origin of humans.
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[edit] Geology
The underlying rock formation derives from the Kaapvaal craton, formed as a precursor island roughly 2.7 billion years ago. This crustal formation became the base of the Waterberg, which was further transformed by upward extrusion of igneous rocks[2]. These extruded rocks, containing minerals such as vanadium and platinum, are called the Bushveld igneous complex. The original extent of this rock upthrust involved about 250,000 square kilometers, and is sometimes called the Waterberg Supergroup.
Sedimentary deposition from rivers cutting through Waterberg endured until roughly 1.5 billion years ago. In more recent time (around 250 million years ago) the Kaapvaal craton collided with the supercontinent Gondwana, and split Gondwana into its modern day continents. Waterberg today contains mesas, buttes and some kopje outcrops. Some of cliffs stand up to 550 meters above the plains, with exposed multi-coloured sandstone.
[edit] Stone Age man at Waterberg
The sandstone formations could retain groundwater sufficient to make a suitable environment for primitive man. The cliff overhangs offered natural shelters for these early humans. The first human ancestors may have been at Waterberg as early as three million years ago, since Makapansgat, 40 kilometers distant, has yielded skeletons of Australopithecus africanus[1]. Hogan suggests that Homo erectus, whose evidence remains were also discovered in Makapansgat, "may have purposefully moved into the higher areas of the Waterberg for summer (December to March) game".
Bushmen entered Waterberg around two thousand years ago. They produced rock paintings at Lapalala within the Waterberg, including depictions of rhinoceros and antelope. Early Iron Age settlers in Waterberg were Bantu, who had brought cattle to the region. The Bantu created a problem in Waterberg, since cattle reduced grassland caused invasion of brush species leading to an outbreak of the tse-tse fly. The ensuing epidemic of sleeping sickness depopulated the plains, but at higher elevations man survived, because the fly cannot survive above 600 meters.
Later people left the first Stone Age artifacts recovered in northern South Africa. Starting about the year 1300 AD, Nguni settlers arrived with new technologies, including the ability to build dry-stone walls, which techniques were then used to add defensive works to their Iron Age forts, some of which walls survive to today. Archaeologists continue to excavate Waterberg to shed light on the Nguni culture and the associated dry-stone architecture.
[edit] European arrival
The first white settlers arrived in Waterberg in 1808 and the first naturalist a Swede appeared just before mid 19th century. Around the mid 19th century, a group of Dutch travelers set out from Cape Town in search of Jerusalem. Arriving in Waterberg, they mis-estimated their distance and thought they had reached Egypt.
After battles between Dutch settlers and tribesmen, the races co-existed until around 1900. The Dutch brought further cattle grazing, multiplying the impacts of indigenous tribes. By the beginning of the 20th century there were an estimated 200 western inhabitants of the Waterberg[3], and grassland loss began to have a severe impact upon native wildlife populations.
[edit] Flora and fauna
There are several sub-habitats within the Waterberg Biosphere, which is fundamentally a dry deciduous forest; according to Hogan: "These sub-habitats include high plateau savanna, specialized shaded cliff vegetation system and riparian zone habitat with associated marshes".
The savanna consists of rolling grasslands and a semi-deciduous forest, with trees such as Mountain seringa, Silver-leaf terminalia and Lavender tree. The canopy is mostly leafless during the dry winter. Native grasses include Signal grass, Goose grass and Heather-topped grass. Indigenous grasses provide graze to support native speciess including impala, kudu, klipspringer and Blue wildebeest. Some Pachypodium habitats are found especially in isolated kopje formations.
Other indigenous mammals include giraffe, white rhinoceros and warthog. Snakes include the black mamba and spitting cobra. In 1905 Eugene Marais studied these snakes of the Waterberg[4]. Some birds seen are the Black-headed oriole and the White-backed vulture[5].
Vegetative cliff habitats are abundant in the Waterberg due to the extensive historic riverine erosion. The African Porcupine uses the protection of these cliffside caves. Some trees cling to the cliff areas, including the Paper tree, whose flaking bark hangs from their thick trunks. of specimens clinging to cliffsides above winding streams below. Another tree in this habitat is the fever tree, thought by Bushmen to have special power to allow communication with the dead. It is found on cliffs above the Palala River including one site used for prehistoric ceremonies, which is also a location of some intact rock paintings.
Riparian zones are associated with various rivers that cut through Waterberg. These surface waters all drain to the Limpopo River which flows easterly to discharge into the Indian Ocean. Red bush willow is a riparian tree in this habitat. These riparian zones offer habitat for birds, reptiles and mammals that require more more water than plateau species. The riverine areas house the apex predator Nile crocodile and the hippopotamus. These wet habitats are almost absent of water-related insects, and the Waterberg is thus considered an almost Malaria-free region.
[edit] Land management
As of the year 2006 about 80,000 people live in the Waterberg, which is considered part of the Bushveld district of the Limpopo Province of South Africa. After cattle grazing wrought ecological havoc in the mid 1900s, the land owners of the region became aware of the benefits of restoring habitat to attract and protect the original species of antelope, white rhino, giraffe, hippopotami, and other species whose numbers dropped in the era of intense cattle grazing.
The rise in eco-tourism has stimulated interest in soil conservation practices to restore original grass species to the Waterberg. Land management practises required are expensive, but repay the landowner with added value of wildlife habitat. There is also a trend of larger farms and open space areas with the resultant advantage of fence removal. This outcome not only benefits large mammal migration, but yields an improved gene pool.
[edit] References
- ^ a b C.Michael Hogan, Mark L. Cooke and Helen Murray, The Waterberg Biosphere, Lumina Technologies, May 22, 2006. [1]
- ^ William Taylor, Gerald Hinde and David Holt-Biddle, The Waterberg, Struik Publishers, Capetown, South Africa (2003) ISBN 1-86872-822-6
- ^ The Encyclopedic History of the Transvaal, Praagh and Lloyd, Johannesberg (1906)
- ^ Eugene Marais, Soul of the Ape, Human and Rousseau (1937)
- ^ Tracey Hawthorne, Common Birds of South Africa, Struik Publishing, South Africa (1998) ISBN 1-86872-120-5
