Arid lands in the Sudan have been subjected to degradation manifested by loss of soil fertility, shortages of fodder and fuel, and moving sands. [Acacia tortilis], [A. senegal] and [Prosopis chilensis] are valuable afforestation species to restore these lands and provide fodder, fuelwood and other products. Animals, particularly goats and sheep, are effective long-distance dispersers of seeds. The ingested seeds are preserved from further attacks of predators and their germination capabilities are enhanced by ingestion and pelleting. Because of the small mass of the droppings, the ingested seeds are transported by wind and water to low-lying places where run-off water usually collects.
The Encyclopedia of World Problems and Human Potential is a collaboration between UIA and Mankind 2000, started in 1972. It is the result of an ambitious effort to collect and present information on the problems with which humanity is confronted, as well as the challenges such problems pose to concept formation, values and development strategies. Problems included are those identified in international periodicals but especially in the documents of some 60,000 international non-profit organizations, profiled in the Yearbook of International Organizations.
The Encyclopedia includes problems which such groups choose to perceive and act upon, whether or not their existence is denied by others claiming greater expertise. Indeed such claims and counter-claims figure in many of the problem descriptions in order to reflect the often paralyzing dynamics of international debate. In the light of the interdependence demonstrated among world problems in every sector, emphasis is placed on the need for approaches which are sufficiently complex to encompass the factions, conflicts and rival worldviews that undermine collective initiative towards a promising future.
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