Pastoralism and Rangeland Management on the Tibetan Plateau in ...

farming l<strong>and</strong>scapes. As topographically the l<strong>and</strong>mass of China tilts from west
to east, this makes the rangel<strong>and</strong>s in the west (accounting for about 41 % of the
of China’s l<strong>and</strong> territory) extremely important since they are the upper-stream
areas of most of the major rivers of China.
Source: Baidu 2010c; Sen 1989
Figure 1: Division between pastoral <strong>and</strong> agricultural regions of China
3.3 Rangel<strong>and</strong>s as an important carbon sink
With the global concern of climate change, increasing attention has been
directed to the contribution <strong>and</strong> potential of rangel<strong>and</strong>s in carbon sequestration.
Well-managed rangel<strong>and</strong>s can act as a carbon sink by fixing <strong>and</strong> storing
carbon in the biomass <strong>and</strong> soil. It is estimated that rangel<strong>and</strong>s store 572.6 billion
metric tons of carbon, accounting for 33 %–34 % of total carbon fixed by the
global ecosystem, only secondary to the forest ecosystem which accounts for
39 %–40 % of the total carbon storage. The rangel<strong>and</strong> ecosystem in China is
said to have a carbon stock of 44.09 billion metric tons <strong>and</strong> 51 % of it is contributed
by alpine or temperate meadows, steppes <strong>and</strong> grassl<strong>and</strong>s (Guo 2010). In
rangel<strong>and</strong> ecosystem, over 90 % of the carbon is stored in soil <strong>and</strong> less than 10 %
is stored in the biomass. Fang et al. (2008) calculated the biomass carbon stock
of rangel<strong>and</strong>s in Qinghai, Tibet, Inner Mongolia <strong>and</strong> Xinjiang <strong>and</strong> concluded
that the total biomass carbon storage is about 0.536 billion metric tons. On the
other h<strong>and</strong>, degraded rangel<strong>and</strong>s have lower carbon fixing <strong>and</strong> storage capacity
<strong>and</strong> could eventually act as a source of greenhouse gas once the thresholds are
exceeded. L<strong>and</strong> reclamation <strong>and</strong> overgrazing are major causes for decrease of
rangel<strong>and</strong>’s carbon storage capacity. By 1998, over 660 million ha of rangel<strong>and</strong>s
have been converted to farming l<strong>and</strong>s worldwide by human beings, resulting in a
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