The variation in genetic constitution between species, populations and individuals, and the barriers between species, form the basis of biological diversity of biodiversity.

Scientists find it convenient to consider biodiveristy from three different angles: genetic, species and ecosystem diversity. These three levels are closely interconnected. Biodiversity is most simply measure as numbers of species per unit area.

The key determinants of an area’s biodiveristy are its evolutionary history and size. Areas whose climate has changed impacting the flow of animal and plant migrations across them, usually exhibit a greater mix of species today, than those that have experienced a stable environment over a longer stretch of time. The larger the area, the greater chance of a wider species diversity.

The Okavango and Chobe river areas in Botswana are the richest floral areas in southern Africa. Lakes Tanganyika and Malawi have a great variety of fish species not found anywhere else in the world. The Kruger National Park (South Africa), Hwange National Park (Zimbabwe), Makgadikgadi Pan Game Reserve (Botswana) and the Selous Game Reserve (Tanzania) are examples of protected areas in southern Africa with a great diversity of wildlife species, both fauna and flora.

The number of species in the world is estimated at between 10 million and 30 million including insects, birds, fish, mammals, plants and other life-forms. But species are disappearing at an alarming rate of several dozens a day.

Threats to biodiversity include farming, livestock-grazing, urban and rural settlement, loss of woodlands, deforestation, poaching and loss of habitat.

Population growth is a major factor behind biodiversity loss. Increasing populations exert pressure on the environment in terms of resources consumed. To support growing populations, more land is needed for agriculture, less land becomes available for many animal and plant species and there is loss of habitat.

A number of species are already extinct in southern Africa: two mammal species (quagga, blue antelope); 34 plant species (most in the fynbos, South Africa); four turtle species (Green, Hawskbill, Olive, Leatherback); two butterfly species( Bashee River Buff, Morant’s Blue). Many other species are threatened.

War has also contributed to the loss of southern African biodiversity. IUCN estimates that Angola may have lost as much as 90 percent of its wildlife in protected areas during the 20 years of war, since 1975. The wild animals in Mozambique’s Zinave National Park, in northern Inhambane Province, were overhunted to supply both urban and army centres.

Genetic diversity is particularly threatened among domestic crops such as sorghum, millet, cowpeas, and groundnuts because of the introduction of hybird and foreign varieties. The indigenous cultivars (plants found only under cultivation) are more acclimatised to the environment than imported breeds. Potential threat to the diversity of marine areas is global warming which may cause a rise in sea level as glaciers melt and water expands due to a rise in temperatures.

This may cause the submergence of low-lying areas, estuaries and islands such as Mauritius and Inhaca.

Island in Mozambique, negatively affecting plant and animal species adpted to those environments. Much of the coastal area of Mozambique is low-lying.

It is also possible that increased temperatures will upset the sex ratio of turtles as their sex at hatching is determined by temperature. Surface-nesting birds, such as African penguins, are likely to desert their nests to avoid excessive heat, leading to the continued decline in their numbers.

People depend on biological resources for food, clothes, shelter and medicines. The ecosystems of forests, savannas, deserts, lakes and seas, farmer’s fields and gardens contain most of the world’s biodiversity. Smaller, but significant quantities, are found in gene banks, botanical and zoological gardens.

The conservation of biodiversity can bring long- and short-term, specific and general benefits to southern African countries. Biodiversity can be considered as a great national asset as are diamonds and / or Oil. The returns and benefits from biodiversity are longer term and in many countries it is largely unstudied and unprotected.

The biodiversity of local crops, medicinal plants, tree, plant and animals species in general, contributes to southern Africa’s food self-sufficiency, development of local pharmaceutical and other industries, and boosts ecotourism. The importance of indigenous plants as the basis of traditional medicines, which are used by over 80 percent of the people of sub-Saharan Africa, cannot be over emphasised. Such plants can also be processed and used in developing modern medicines.

Ecologists say the more people know about ecosytems, the more they understand how every species is connected to all others. Loss of each of these "building blocks" brings the whole system a step closer to collapsing.

The southern African region has come up with some innovative programmes to protect biological diversity both in and outside protected areas. These are aimed and ---------------depleted stocks, and in some cases, keeping wildlife populations within the carrying capacity of the land. The programmes also seek the support and participation of people in communal areas and on private land.

Game from private land has been used to restock protected areas where wildlife populations have been depleted.

Community – based wildlife management is another approach for biodiversity conservation; where wildlife in and around rural areas is managed and utilised for the benefit of the residents. Some of these programmes in the region are:

• Selous Conservation Programme in Tanzania;
• Wetlands Programme in the Kafue and Bangweulu flats of Zambia;
• Administrative Management Design for Game Management Areas (ADMADE) in Zambia;
• Wereldsend Community in Namibia; and
• Communal Areas Management for Indigenous Resources (CAMPFIRE) project in Zimbabwe.

The more control and benefit people get from wildlife, the greater the incentive to conserve it.

Biotechnology

A new dimension has been added to the value of biodiversity in recent years with the growth in biotechnology. This is a set of techniques which allow specific artificial changes to be made in the genetic material of plants, animals and micro-organisms, leading to the increased availability of food and the protection of the environment.

But the promises of biotechnology are essentially dependent on the biodiversity that has evolved over millions of years. Every loss in biodiversity, every species extinction, is a loss of future potential use to people.

In southern Africa, the growth of agricultural productivity requires, among other inputs, the use of improved varieties of commercial and subsistence crops. Future breeding programmes will need disease resistant and adaptive characters of local germplasm (a susbstance in germ cells that transmits hereditary characteristics to the offspring).

Black rhino, giant sable - poaching / hunting

Wild dog, cheetah, hyena - elimination by farmers as pests

Protea - habitat loss

African penguin - egg-collection, lack of food, contamination by toxic

Chemicals

Shoe –billed stork - illegal trade

Geometric tortoise - overexploitation of eggs and adults for meat, shells

(+ all other turtles species) For ornaments, and skins for leather

coconut crab - for use as an aphrodisiac

mollluscs - indicrimante use of pesticides

to kill insects and grasshoppers

Source: SADC/IUCN/SARDC, State of the Environment in Southern Africa.

Maseru/ Harare, 1994, pp. 169-171

Seed samples of varieties of Themeda triandra, one of the most important grasses in southern Africa, are now resting in a gene bank in Lesotho. This grass can be useful in reclaiming degraded land in the region.

International cooperation can benefit biodiversity protection. Through organisations such as the World Conservation Union (IUCN) and World Wide Fund for Nature and Natural Resources (WWF), the region has received technical, monetary and material support.

Debt-for nature exchange involves the purchase of foreign debts by international donors in return for setting aside land for conservation where no development should take place. So far, in southern Africa, only Zambia has such a deal. The Zambian government agreed to allow WWF to manage the Kafue and Banweulu flats in return for the writing off of US$2.27 million debt.

The Food and Agriculture Organisation (FAO) oversees the International Board for Plant Genetic Resources (IBPGR). This institution maintains gene banks to assure the long-term survival of an array of plant species, particularly cereal crops. The FAO also supervises an Animal Genetic Resources Data Bank. These resources are available to all UN member states.

Due to global concern on biodiversity decrease, the 1992 Earth Summit in Rio de Janeiro, Brazil, finalised a global Convention on Biodiversity which came into effect at the end of 1993. All 12 SADC countries are signatories to this convention.

There are several treaties dealing with biodiversity either in whole or in part, such as the Convention on International Trade in Endangered Species of Fauna and Flora (CITES), the Convention on Wetlands of International Importance(Ramsar), the Convention on the Protection of World Cultural and Natural Heritage Sites, and the African Convention on Conservation of Nature and Natural Resources.