The goal of nature conservation is to plan, facilitate, maintain and enhance sustainable natural environments and facilities that contribute to the quality of life and which meets the needs of the present and future community (Nel, 1996).

South Africa's earliest conservation organisations, formed in the 1800's, were game preservation associations, concerned primarily with protection of wildlife. Single species conservation formed the focus of these conservation efforts until recently, when people became aware that all species are dependent on their habitat and life support systems. The realisation that the earth's resources (living and non-living) are both finite, and essential for the survival of human and other life, contributed to a broadening of the concept of conservation to include, as well as wild animals, all the interacting components of an ecosystem that are necessary for its healthy functioning. Today, conservation has come to be described as the wise use of the earth's resources such that they will be able to support, or sustain, all life for generations ahead (Enviro Facts, 1999d).

The Greater Johannesburg area contains a variety of fauna and flora, some of which are indigenous to the area. Development has long enjoyed priority over conservation in the metropolitan area. With the introduction of the Environmental Act of 1995, greater awareness and consideration will be taken of environmental issues. It is also now compulsory for an Environmental Impact Assessment to be conducted before any new development may take place. This process qualifies and quantifies the significance of the natural environment and ensures that the negative impacts of a development will be minimised and its positive benefits enhanced. It also aims to protect any scarce or endangered species present, and to keep ecosystems intact.

Greater Johannesburg is situated in the Rocky Highveld Grassland zone of the Grassland Biome of South Africa (Low and Rebelo, 1996). The natural features of this zone include:

Altitude: 1 500 – 1 600m.

Climate: Summer rainfall between 650 and 750mm per year, and temperatures between –12ºC and 39ºC, with an average of 16ºC. The highest rainfall of >750mm is found in an east-west zone from the west of Roodepoort to the Johannesburg CBD area. Rainfall decreases away from this zone in a northern and southern direction.

Conservation status: 65% transformed and 1,38% conserved.

Key environmental parameters: Fire, frost, exposed sites.

Geology: The area is underlain by many different geological formations. These range from the more stable granites in the north, to the less stable shales and dolomites in the south. The geologically sound areas (like the igneous granites and basalts of the north), have already been developed, while the less stable areas of dolomite and shale, and areas of mining hinder development and investment. The central Witwatersrand Ridge and mining area is made up of quartzite, while lava intrusions surround the Soweto area. Dolomites are found in the Lenasia area, going over into shales and quartzite around Ennerdale and Orange Farm.

Soils: Mainly shallow, rocky soils.

Vegetation: The area falls into the highveld mixed grassland zone, dominated by indigenous grasses such as Loudetia simplex (common russet grass), Themeda triandra (red grass) and Trachypogon spicatus (giant spear grass), as well as indigenous trees such as Acacia caffra (common hook thorn) and Rhus leptodictya (Karee). The vegetation includes pure grassland, bush grassland, mixed grassland, temperate mountain bushveld and wetland areas. A lot of different species of exotic plants, like Blue Gum Trees are also found in the area, which influences the water table, as well as the drainage and erosion capacity of the area. An indigenous plant or animal is one which occurs naturally in an area, and has not been assisted in its travels by people (Enviro Facts, 1999g). A species which does not occur naturally, but which has been introduced there by people, is called an alien (exotic). A few alien species reproduce and spread, unassisted by man, into areas where they are not wanted - these invasive aliens pose a serious threat to nature conservation. Highveld areas, including Greater Johannesburg, suffer mainly from wattle and bramble invaders, but also from lantana, prickly pear and bugweed (Enviro Facts. 1999g).

Water: The metropolitan area receives an average rainfall of 650-750mm per year. The entire southern African region is prone to droughts, which also affects Greater Johannesburg. Water is a very scarce resource in this metropolitan area, with a population of 2,5 million growing at a rate of 2,4% per year. Current water consumption levels are not sustainable, and problems such as water pollution and declining water quality aggravates the problem of scarce water resources.

Natural Resources: Greater Johannesburg not only possesses a wide variety of minerals, but also other natural resources such as rivers, pans, ridges and cliffs. These can be found in all parts of the metropolitan area. Pans and lakes are found mainly in the east, large ridges occur in the west and cliffs in the north. Greater Johannesburg also has a wide range of parks, botanical gardens and nature reserves that need to be protected against the forces of urban development.

Biodiversity: The protection of a wide range of fauna and flora, especially with regard to threatened species, is of a high priority in a metropolitan area where rapid urbanisation is taking place and informal settlements are sometimes created overnight in undeveloped areas.

Energy: The urban structure resulting from the apartheid era has caused Greater Johannesburg to be extremely energy-inefficient. The sustainable use of fuel, electricity and gas needs to be given more attention.

REFERENCES

Enviro Facts 1999d: Conservation. http://www.botany.uwc.ac.za/EnvFacts/facts/conserve.htm

Enviro Facts 1999g: Indigenous, Alien and Invasives. http://www.botany.uwc.ac.za/EnvFacts/facts/aliens.htm

Low, A.B. & A. Rebelo 1996: Vegetation of South Africa, Lesotho and Swaziland. DEAT: Pretoria.