Geoscience Reference
In-Depth Information
Table 26.4. Primary aims decided at the Desert Margins Initiative,
Nairobi, 23-26 January 1995. (Adapted from International Crop
Research Institute for the Semi-Arid Tropics, 1995 and author's notes.)
Overall goal
To contribute to sustainable food security and poverty alleviation
Overall objective
To promote innovative and action-oriented dryland management research to
arrest land degradation
Specific objectives
Understanding land degradation
Assessing dryland management practices
Evaluating the role of livestock in the rangeland/arable land continuum
Designing policies, programs and institutional options
Improving natural resource management
Fostering domestication of tree species
Formulating drought management strategies
Enhancing institutional capacities
Exchanging technologies and information
26.9 Conclusion
Given the widespread problems of land degradation and desertification discussed in
Chapter 25 , the question that comes most immediately to mind is whether or not we
can indeed live in an ecologically sustainable manner in the deserts and their semi-
arid and seasonally wet margins. Our survey of the past offers grounds for cautious
optimism. Plants, humans and other animals have adapted in a variety of effective and
often highly ingenious ways to the extremes of life in deserts, where water is, and
always will be, the limiting factor governing life in these harsh environments. Faced
in the past with extreme events, such as prolonged drought, all living organisms have
responded in one of three ways. Some have migrated into less harsh environments, as
did the nomadic Neolithic pastoralists who moved out of the Sahara when it dried out
some 4,500 years ago. Others adapted and remained, as did the San hunter-gatherers
of the Kalahari. Still others neither adapted nor migrated and instead became extinct.
Four conditions seem necessary if we are to continue to live in harmony with the
desert world. First and most fundamental is the need to conserve desert ecosystems,
since the only means of achieving a net increase in primary productivity on this earth
is through photosynthesis, which requires plants to be able to capture the energy from
the sun and carbon dioxide from the atmosphere to manufacture additional plant food
in the form of starch. Second, taking due heed of the first law of thermodynamics,
we should not systematically remove materials from any natural system or humanly
modified system at a rate that is faster than the rate at which that system can replenish
those materials. Extracting groundwater at a rate faster than its recharge rate disobeys
this principle, as does allowing soils to erode at a rate faster than they can develop.
Search WWH ::




Custom Search