The cost of conserving biodiversity is less than the penalty of allowing its destruction. Once lost, this heritage cannot be recovered.

1.4-1.75 million species have been identified but scientists believe that there are over 13.5 million more species. The size of the grey drawings indicates the number of species known, while the larger shadow indicates the total estimated number.

The diversity of life on earth is essential to the survival of humanity. Yet it is being lost at an unprecedented rate. Natural habitats are being destroyed, degraded and depleted, resulting in the loss of countless wild species. Traditional crop varieties and animal breeds are being replaced with new ones that are more suited to modern agriculture.

When natural diversity is lost, so is irreplaceable genetic material, the essential building blocks of the plants and animals on which agriculture depends. These plants and animals are the result of 3 000 million years of natural evolution -and 12 000 years of domestication - and selection. Of the thousands of plant species that can be used for food, only 15-20 are of major economic importance. In fact, only a handful supply the dietary energy needs of most of the world's population. Since 1900, however, about 75 percent of the genetic diversity of agricultural crops has been lost.

In India, there will soon only be 30-50 rice varieties covering an area where 30 000 once flourished. Half of the animal breeds that existed in Europe at the start of the present century are now extinct, and one-quarter of the livestock breeds in the rest of the world are now at high risk of loss. The traditional knowledge and skills of indigenous peoples who selected, bred and cultivated such varieties over thousands of years - are also disappearing, often along with the people themselves.

The loss of genetic resources has accelerated with the spread of intensive agriculture and high-yielding crop varieties to large parts of the developing world, replacing the traditional diversity of crops with monocultures. Yet the varieties being lost may contain genes that could be used to develop even more productive varieties or to improve resistance to pests. The N'Dama cattle of West Africa, for example, have developed tolerance, over thousands of years, to trypanosomiasis, which threatens some 160 million other domesticated animals in Africa, costing an estimated US$ 5 000 million a year in meat production alone.

Popular movements to conserve traditional crop varieties are spreading throughout the world. The Seed Savers Exchange, a network of around 1 000 farmers and gardeners in the United States, locates and conserves thousands of varieties of endangered vegetables. KENGO, a network group in Kenya, promotes the conservation and use of indigenous tree species.

FAO stresses the importance of building the capacity of developing countries to conserve, develop and use diversity sustainably as a means of reducing hunger and poverty. The Organization has pioneered the concept of Farmers' Rights which recognizes that farmers and rural communities, especially those in the developing world, should be rewarded - and to no lesser extent than plant breeders -for the contribution they make to the creation, conservation and availability of genetic resources.

Number of species by area

Number of species per 10 000 square kilometres, 1990-92
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Domesticated animals at risk