Advantage of Water Shade in Both Natural Pasture and Improve Forages, Constraints and Option of Range Plats on Rage Ecology of Pastoral and Agro Postural in the Low Land Areas of Ethiopia. A Systematic Review (July, 2015)

The rangelands of East African countries are almost exclusively found in dry land areas where there is general moisture deficit (Coppock, 1994; Herlocker, 1999). The dry land ecosystem covers areas where rainfall is low, variable, often unreliable, and generally unevenly distributed throughout the year (UNEP, 1992; IUCN, 1999). Dry lands have highly seasonal rainfall regimes with significant inter-annual variability and mean annual precipitation values which vary from about 800 mm in summer rainfall areas to 250 mm in winter regimes (IUCN, 1999). They are the habitat and source of livelihood for about one quarter of the earth’s population. It is estimated that these ecosystems cover one third of the earth total land surface and about half of this area is in economically productive use as range or agricultural land (CCD Secretariat, 1997). According to FAO (1996) classification, Ethiopia is one of the thirty-six dry land developing countries in the world. The dry lands, which includes the arid, semi-arid and dry sub-humid areas The rangelands of Ethiopia cover about 60% of the total area and are the major sources of livestock feed (BLPDP 2004; PFE 2004). These areas are characterized by lowland plains, relatively harsh climate with low, unreliable and erratic rainfall and high temperatures (Ayana, 2007). Of the total livestock population of the country, about 40% cattle, 75% goats, 25% sheep and almost 100% of camels are raised in the rangelands (Alemayehu, 2004). The rangelands are not only known for livestock rearing, but there are also many wildlife, parks, sanctuaries, and reserves (Abule et al 2005). In most developing countries, rangelands have contributed to the major portion of feed consumed by ruminants. In Ethiopia more than 90% of the ruminant livestock feed on natural pastures, which vary in composition depending on the agro-ecology (Alemayehu, 2005). Rangeland is defined as land producing natural forage for animal consumption (Coppock, 1994). Most rangelands are at best only marginally suitable for arable cropping, and in Ethiopia there are extensive areas where livestock raising on the natural vegetation is the only possible types of land use. The lowlands of the country are found below 1500 meter above sea level (masl) and are estimated to cover about 78 million hectares, which is about 61–65% of the total land area of the country (Friedel et al. 2000). They are home for about 12-15% of the human and 26% of the livestock population (Beruk and Tafesse, 2000). Pastoral communities dominate the lowland areas of the country. Low human population density and highly variable and uncertain rainfall characterize the lowland areas. In the pastoral community, grazing biomass is entirely determined by the amount, pattern and timing of rainfall.The rangelands are presently undergoing extensive deterioration both in quantity and quality (Belaynesh, 2006). The rangelands have limited capabilities in vegetative production and in providing reasonable animal sustenance and production due primarily to adverse environments including low and seasonal rainfall; moisture gathering winds; varying degrees of poor soil; soil erosion; lack of or inadequate forage and grazing management; and overstocking rates (Alemayehu, 2005). Intensity of grazing and browsing and restriction of livestock mobility have more serious consequences on the rangelands than the number of animals owned by the pastoralists. Community structure is vastly altered when improper grazing continues for long periods (Holcheck et al. 1998)