Biodiversity is a popular way of describing the diversity of life on earth: it includes all life forms and the ecosystems of which they are a part. World Food Day — the anniversary of FAO's founding on 16 October 1945 — celebrates, in particular, that part of biodiversity that nurtures people and contributes to long-term food security for all. Biodiversity forms the foundation for sustainable development. It is the basis for the environmental health of our planet and the source of economic and ecological security for future generations.
|In the developing world, biodiversity provides the assurance of food, countless raw materials such as fibre for clothing, materials for shelter, fertilizer, fuel and medicines, as well as a source of work energy in the form of animal traction. The rural poor depend upon biological resources for an estimated 90 percent of their needs. In the industrialized world access to diverse biological resources is necessary to support a vast array of industrial products. In the continuing drive to develop efficient and sustainable agriculture for many different conditions, these resources provide raw material for plant and animal breeding as well as the new biotechnologies. In addition, biodiversity maintains the ecological balance necessary for planetary and human survival.|
We are losing biological diversity at an unprecedented rate. The loss of species is not new. In the course of geological time one has only to recall the fate of the dinosaurs. By and large, however, the disappearance of species in past eras has occurred by virtue of natural processes within the context of evolutionary time-scales. Today, however, human activities contribute more to the loss of biodiversity than any other factor.
Biological resources are renewable resources, but they are being exploited at rates that exceed their sustainable yield. Human destruction of habitats, whether exploited for commercial or subsistence reasons, is the greatest threat. The clearing of land for agriculture, overgrazing of grasslands, cutting and burning of forests, unsustainable logging and fuelwood collection, indiscriminate use of fertilizers and pesticides, over-watering of crops, overexploitation of fisheries, draining and filling of wetlands, poor water management, urbanization and pollution of air and water, figure prominently in the degradation of our biological resources. Five to seven million hectares of cultivated land are destroyed every year.
Loss of biodiversity is frequently presented as an environmental problem, but the underlying causes are essentially social, economic and political. The excessive and unsustainable consumption of resources by a small but rich minority of the world's population, combined with the destructive impacts of the world's poor and hungry in a desperate bid for survival, have destroyed or overexploited habitats worldwide.
Genetic erosion — the reduction of diversity within and the main cause of extinction of a species — is a global threat to agriculture. The greatest loss of crop genetic resources results from the introduction of modern, uniform plant varieties in place of a mix of traditional ones. The Green Revolution introduced high-yielding varieties of rice and wheat to the developing world, but displaced traditional varieties and their wild relatives on a massive scale. In India, for example, agronomists predict that just ten rice varieties will soon cover three-quarters of the total rice area where once over 30 000 different varieties were grown. In the United States, over 85 percent of the 7 000 or so apple varieties grown in the last century are now extinct.
The same is true of animal genetic resources. The introduction of a very few modern breeds that are better suited for the high input-output of industrial agriculture is displacing the diversity of indigenous livestock breeds. In Europe, half of all the breeds of domestic animals (horses, cattle, sheep, goats, pigs and poultry) that existed at the beginning of the century have become extinct. A third of the remaining 770 breeds are in danger of disappearing within the next 20 years.
What is biodiversity?
Biological diversity is made up of all species of plants and animals, their genetic material and the ecosystems of which they are a part:
Genetic diversity refers to the variation of genes and genotypes between and within species. It is the sum total of varied genetic information contained in the genes of individual plants, animals and microorganisms that inhabit the earth. Diversity within a species gives the ability to adapt to change whether in environment, climate and agricultural methods or the presence of new pests and diseases.
Species diversity refers to the variety of species within a given area.
Ecosystems consist of interdependent communities of species (complex mixes of diversity between and within species) and their physical environment. The extent of an ecosystem or habitat is imprecise; a single ecosystem may cover thousands of hectares or just a few. They include major natural systems such as grasslands, mangroves, coral reefs, wetlands and tropical forests as well as agricultural ecosystems that, while depending upon human activity for their existence and maintenance, have characteristic assemblages of plants and animals.
Why is biodiversity important?
Genetic diversity in agriculture enables crops and animals to adapt to different environments and growing conditions. The ability of a particular variety to withstand drought or inundation, grow in poor or rich soil, resist one of the many insect pests or diseases, give higher protein yields or produce a better-tasting food are traits passed on naturally by its genes. This genetic material constitutes the raw material that plant and animal breeders and biotechnologists use to produce new varieties and breeds. Without this diversity we would lose the ability to adapt to ever-changing needs and conditions. Sustainable agriculture could not then be achieved in many of the world's different food production environments.
Diversity among individual plants and animals, species and ecosystems provides the raw material that enables human communities to adapt to change — now and in the future. Deprived of biodiversity, the ability of humankind to meet the challenges resulting, for example, from global warming and ozone depletion would be severely limited. The diversity found within the small number of plant and animal species which form the basis of world agriculture and food production remains a small but vital part of the earth's biodiversity. Through modern biotechnologies wild diversity can also be incorporated into crops and contribute to world agricultural development.
Biodiversity for sustainable development
The biological resources of each and every country are important, but not all are equally endowed. In general, a small number of countries lying within the tropics and subtropics account for a very high percentage of the world's biodiversity. Tropical forests, for example, cover only 7 percent of the earth's land surface, but they are estimated to contain at least 50 percent of all species.
The most important food crops, however, appear to have originated in areas that have pronounced seasons, not in the tropical forests. This tends to coincide with arid and semi-arid zones, which include famine-prone countries such as Ethiopia. It makes sense, therefore, to look for sources of certain food crop diversity in such areas. A single Ethiopian barley plant, for example, has yielded a gene that now protects California's annual barley crop from yellow dwarf virus.
The fact that the richest nations are home to the smallest pockets of biodiversity while the poorest are stewards of the richest reservoirs underscores the interdependency of all nations, and the urgency of crafting common strategies for sustaining biodiversity that share both responsibility and benefits. On the eve of the twenty-first century, the challenge for the global community is not to save biodiversity for its own sake, but to ensure that biodiversity is used sustainably and equitably for human development.
F A C T S
Nobody knows how many species are disappearing (or being generated) on the earth: probably fewer than 10 percent of species have even been given a scientific name.
Since the beginning of this century about 75 percent of the genetic diversity among agricultural crops has been lost.
The rural poor depend upon biological resources for an estimated 90 percent of their needs.
A 13.7 km2 area of La Selva forest in Costa Rica contains almost 1 500 plant species — more than all those found in the United Kingdom's 243 500 km2.
Panama contains more species than all of North America.
In the United States, 25 percent of all prescriptions dispensed by pharmacies are substances extracted from plants. Another 13 percent come from microorganisms and 3 percent from animals.