Fjölrit RALA - 05.12.1999, Side 90

Fjölrit RALA - 05.12.1999, Side 90
88 Rangeland degradation in Northern China whatever the cause, would be reduced. Rangeland restoration implies the increasing grazing rate to a standard matching that which it originally had. Rangeland degradation is the most extensive among the major types of current landuse. Few countries have less than 50 percent of their pastoral lands degraded (World Bank 1992). Overgrazing by livestock is the principal land problem in the arid and semi-arid regions, coupled with landuse change to cultivated farmland in the many countries short of farmland (Barrow 1991). The high percentage of the world’s rangeland that suffers from over use stems frorn the extensive, low intensity character of pastoral land use, the slow response to land management changes in arid climates, and the social and economic problems associated with reducing livestock numbers on heavily used rangelands (Narjisse 2000). Reducing populations of cattle, sheep, and goats among people living on the margin of survival cannot be done without providing other sources of livelihood and that is rarely available. China has a markedly higher percentage of degraded rangelands than the countries in the same latitude, primarily because of the heavier grazing pressure and the conversion to farmland (Jia 1995). In- vestigations have shown that more than 70% of the Ordos grassland is degraded and undergoing retrogressive succession. The community composition is being simplified, good herbage species are being reduced, production is declining, and environmental conditions are worsening. The state and functton of the Ordos rangeland Landforms and Iandscapes Located at the northem part of China, the Ordos Plateau is bordered by the Yellow River in the west and north, and the Loess Plateau in the south. The plateau can clearly be divided into four parts according to landform and landscape; the Jungle Loess Hills in the east, the Kubuqi and Maowushu Sandy Land stretching north to south, the Wsheng Basin in the center, and a dry plateau in the west (Shi 1991). These four land- forms and landscape units are covered by tme steppe of Stipa bung- eána, shmbs of Artem- isia spp., salt meadows and marshes, and desert steppe of Stipa brevi- flora, respectively (Jia 1995). The great varia- tion of landform and landscape make the plateau featured by a higher ecosystem diver- sity than most of the other regions (Li 1995) (Figure 1).
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