Grasslands of the World.pdf - Disasters and Conflicts - UNEP

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Grasslands of the world
of the total degraded rangeland in the whole of the Tibetan Autonomous
Region (Ciwang, 2000).
Seriously degraded alpine meadow is often termed “black beach”, since the
Kobresia -dominated community has deteriorated to such a degree that most of
the sedges and associated grasses have disappeared, leaving annuals and bare
soil. The dynamics of this degradation are not well understood; it is usually
blamed on overgrazing and the burrowing of pikas, but there is increasing
evidence that climate change and desiccation may play a major role in vegetation
changes (Miehe, 1988). Livestock may just accentuate natural ecological
processes instead of being the underlying cause.
THE TIBETAN PASTORAL PRODUCTION SYSTEM
Tibetan pastoralism has evolved through long-term adaptation and persistence
by herders (Ekvall, 1968; Goldstein, 1992; Goldstein and Beall, 1991; Miller,
1999b). Pastoralists kept a mix of livestock in terms of species and class and used
a mosaic of grazing sites, exploiting seasonal and annual variability. Herders
bartered products (Plate 8.8) for grain and supplies; quite elaborate trade linkages
(Plate 8.9) developed between pastoral and agricultural areas; traditional
pastoralism was more than subsistence oriented. Tibetan pastoralism is distinct
ecologically from that of other semi -arid regions, except Mongolia (Ekvall,
1974), since it is separated from agricultural areas by temperature not aridity
(Ekvall, 1968; Barfield, 1993; Goldstein and Beall, 1990; Miller, 1998a). The yak
(Plate 8.10), which is superbly adapted to the cold Tibetan Steppe , also distinguishes
Tibetan pastoralism (Cai and Wiener, 1995; Miller, 1997b).
Plate 8.8
Yaks transporting wool.
DANIEL MILLER