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
Selected Highlights from Research for Dryland
Seed fairs to promote plant genetic
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
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
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
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