Dryland Agrobiodiversity

The Convention of Biological Diversity (CBD) is a legally binding agreement signed at the 1992 United Nations Conference on Environment and Development (UNCED), which is aimed at the conservation and sustainable use of biodiversity,  and the fair and equitable sharing of its  benefits. One hundred sixty-eight countries have ratified the Convention since it entered into force by the end of 1993. It explicitly recognizes national sovereignty over the biological resources within a country's borders, with access to others, subject to mutually agreed terms and prior consent. The CBD recognizes the intrinsic value of the biological diversity and expresses the signatory Parties' concern over the extent and speed of its degradation and the need to take action to prevent further losses.

Biological diversity has been defined by the CBD as the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems, and the ecological complexes they are part; this includes diversity within species, between species, and of the ecosystems.  Biological diversity embraces the total variability of all living organisms and the ecological complexes they inhabit and occurs at three levels: the number of different species, the different combinations of species within ecosystems, and the different combinations of genes within species (IPGRI, 1999).

Agricultural biodiversity or agro-biodiversity includes all components of biological diversity relevant to food and agriculture. It encompasses the variety of animals, plants and micro-organisms, at genetic, species and ecosystem levels, which are necessary to sustain key functions of the agro-system, its structure, and processes for, and in support of, food production and security (CBD-document SBSTTA-5-10e). It occupies a unique place within the biological diversity and is essential to satisfy basic human needs for food and livelihood security. Agro-biodiversity is actively managed by farmers. It contains:

* Genetic resources for food and agriculture (harvested crop varieties,
   livestock breeds, fish species and non-domesticated wild relatives,
   forests, rangelands and aquatic ecosystems);
* Components of agriculture biodiversity that provide ecological
   services (non-harvested species within production ecosystems that
   support food provision, including pollinators, nutrient cycling
   species, natural enemies), as well as services important to
   agriculture such as water catchment, maintaining water quality,
   carbon sequestration, and maintenance of local wildlife and
   habitats; and
* Biotic factors affecting the agricultural biodiversity and the
   socio-economic factors that are shaping it through human activities
   and management.

Dryland agro-biodiversity: 

The dryland areas have ratios of precipitation and evapotranspiration ranging between 0.05 and 0.65. They include semi-arid regions with annual rainfall below 600 mm, arid regions, and hyper-arid regions. Drylands occupy 6.1 billion hectares representing more than 41% of the total global land area with an average annual net primary production of 1200-1500 kg per hectare. Over one billion people, or  one-sixth of the world population, live in the drylands. The dryland agro-biodiversity supports the livelihood of these people  and is maintained within fragile environments. Therefore, drylands agrobiodiversity deserves special attention at national, regional and international levels.

The Subsidiary Body on Scientific, Technical and Technological Advice (SBSTTA) of the CBD recommended to the Conference of Parties to establish a program on dryland biodiversity including grassland, savannah, and Mediterranean lands. Although the tropical forests are known for their richness in species, with probably half of the total higher plant species, the dryland areas may be as important, if not more, in terms of the attributes of the species found in these regions.

* The biological diversity of drylands is very significant and valuable
   because of its high species diversity and high endemism found
   within some biomes. Resistance to harsh environments such as
   drought and heat makes the local germplasm a vital source of
   genes for breeding efforts.

Among the estimated 250,000 flowering species, only 3,000 are food source. Some 200 species are domesticated but only 15-20 species are of major economic importance (Harlan, 1992). Interestingly, most of these major food crops originated in the drylands. The Mediterranean-type ecosystems are exceptionally important in this regard. They contain 4 out of 18 hot spots of endemic flora.  One of the three nuclear centers of agricultural origin defined by Hawkes (1983), the Near East region is the center of origin for wheat, barley, lentils, forage species and many fruit trees. The species which originated from this area are feeding over 38 % of the world's population. Wheat alone accounts for about one-third of the global food production.

The ecosystems in the drylands are fragile. The degradation of habitats and the loss of related biodiversity are already leading to irreversible situations responsible for migration of local communities, desertification and increasing mass poverty. The drylands degraded soils could be a potentially significant source of carbon emissions.

References cited
   CBD. 2000. Documents on the fifth meeting of the Subsidiary Body
   on Scientific, Technical and Technological Advice. In
   www.biodiv.org/sbstta5/Html/SBSTTA-5-10e.

    Harlan, J.R. 1992. Crops and man. Am. Soc. Agron. Inc. Madison,
    Wisconsin, U.S.A., 284 pp.

    Hawkes, J. G. 1983. The diversity of crop plants. Harvard
    University Press, Cambridge, Massachusetts and London.

    IPGRI. 1999. Diversity for development. The New Strategy of the
    International Plant Genetic Resources Institute, IPGRI, Rome,
    Italy.