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Sustainable Use of Biodiversity in Drylands

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Arid, semi-arid and sub-humid areas encompass a wide range of natural habitats, including grasslands, savanna, barren deserts, scrublands, woodlands and forests. These lands possess a rich array of biodiversity that is unique in its ability to survive in and adapt to dry conditions.

Biodiversity is vital for maintaining the health of dryland ecosystems. The loss of a few species may reduce ecosystem resilience significantly, with dire consequences for human livelihoods. A diverse array of domesticated and wild plant species provide people with food, livestock and wildlife with feed as well as many other goods and services.

Equally valuable is the rich genetic wealth tied up in domesticated animals. The estimated 4,000 animal breeds known around the world are gaining importance in the fight against poverty, hunger and disease. But some 30 percent of the world's domesticated animals, most of which are found in the tropics and have never been developed, now face the prospect of extinction.

Pastoral livestock production can easily coexist with wildlife. But as crop production is extended into grasslands, wildlife populations decline dramatically. So, a major challenge in areas such as the Mara-Serengeti ecosystem in southwestern Kenya and northern Tanzania is to manage conflicts between cropping, pastoral livestock production and wildlife-based tourism and enhance the benefits from these competing activities.

Biodiversity contributes vitally to agriculture in drylands, as it does in other ecosystems. The wild relatives of staple foods often contain genes that are useful for crop improvement. And the cover provided by diverse vegetation is critical for soil conservation and for the regulation of rainfall infiltration, surface runoff and local climates. Through activities such as overgrazing, deforestation and the expansion of cultivated land, agriculture may contribute to biodiversity loss, which helps trigger desertification. Once this process is underway, it not only threatens dryland agriculture and pastoralism but also leads to further erosion of biodiversity.

To promote the protection and sustainable use of this valuable resource, scientists have opted in recent years for a research approach that addresses the challenges of agriculture and the management of biodiversity and other natural resources in an integrated fashion. This approach aims to promote diversified rural livelihoods in drylands, based on sustainable management of genetic resources.

Selected Highlights from Research for Dryland Development

Seed fairs to promote plant genetic diversity: A project carried out by the International Plant Genetic Resources Institute (IPGRI) with NGOs and other partners in Mali and Zimbabwe is demonstrating how dryland farmers manage and conserve their plant genetic resources and how to spread best practices. It is also showing how farmers can use these resources to cope with the effects of drought and desertification and improve their livelihoods.

One valuable technique, pioneered in eastern Africa by NGOs working with several CGIAR Centers, involves "seed fairs" organized by rural communities. They offer farmers an opportunity to share information and experience and to display and swap samples of the crops and other plants they grow. The emphasis is on variety, not perfection or abundance, and prizes are awarded for the most diverse displays rather than for the finest crops. International aid agencies have created programs that provide farmers with vouchers for buying seed at these fairs. This measure reinforces local seed systems rather than undermining them, as did the previous practice of introducing imported seed in connection with disaster relief.

Managing trees in agricultural landscapes: Trees are scarce but important in drylands. They capture and recycle nutrients and water, stabilize hillsides and sand dunes, and provide diverse products that are important for people and animals.

The semi-arid Parklands of West Africa provide one example of a traditional system that integrates trees, crops and livestock. Spanning the whole of the Sahel, the Parklands sustain more than 40 million people but are believed to be undergoing rapid degradation in many areas.

One promising approach for reversing the trend is agroforestry. This is the science of integrating trees into agricultural landscapes, where they can help strengthen food security, raise incomes, and restore soil fertility. For example, various live fence technologies developed by the World Agroforestry Centre have proven useful in Africa's Sahel region for protecting market gardens from livestock that roam and graze freely. Some live-fence species have further uses, providing fruit and other useful products, such as tanning chemicals and dyes.

A particularly valuable species in Parklands is the Shea tree. It provides important environmental services, and its products contribute to human nutrition and income. One of these products, shea butter, is controlled mainly by women, and benefits from its sale are shared among all members of rural families. The World Agroforestry Center and its partners are engaged in a project that seeks strategies by which women can improve the processing of shea butter and thus command higher prices for this value-added product.

Fodder banks are another promising option, developed by the International Livestock Research Institute (ILRI). Small areas are enclosed by a fence and sown with forage legumes. Farmers then use the fodder bank as they would a pantry, drawing on it when green grass is in short supply during the dry season, In addition to helping reduce livestock pressure on Parklands, the forage legumes offer the further advantage of nourishing the soil through the accumulation of nitrogen in their roots. An ILRI study conducted in the late 1990s showed that this technology is spreading across West Africa and enhancing livestock productivity.

Arid forest lands resist the sands of time: CGIAR researchers are also working at the policy level to ensure that Africa's dry forests get the attention they deserve from land planners and other decision makers. Working with NGOs and research and development organizations at all levels of government, the Center for International Forestry Research (CIFOR) is building a scientific basis for policies that encourage such practices as opening dry forests to small-scale, sustainable use; marketing of dry forest products, like honey and charcoal; and development of eco-tourism.