Evaluation of oasis ecosystem risk by reliability theory in an arid area: A casestudy in the Shiyang River Basin, China
LI Wei-de , LI Zi-zhen , WANG Ji-quan
DOI:
Received August 20, 2006,Revised November 24, 2006, Accepted , Available online
Volume 19,2007,Pages 508-512
- Summary
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Ecosystem risk is a new concept in understanding environmental problems. It is important to study and develop quantitative methods
for regional ecosystem risk analysis. In this study, some new indicators and methods formeasuring oasis ecosystem risk were established
using reliability theory. These indicators are linked to water resource, which is the key restricting factor in arid area oasis ecosystems.
They have clear meanings and can also be compared in different arid area oases. A case study in the Liangzhou oasis of the Shiyang
River Basin in China shows how to calculate these ecosystem risk indicators. The results of the case study are as follows: the reliability
indicator, risk indicator, stability indicator, and integrated loss indicator of the Liangzhou oasis are 0.686, 0.314, 0.743, and 0.301,
respectively. This means that the reliability degree of the oasis’s ecosystem safety is 68.6%; the degree of risk that it is unsafe is 31.4%;
the stability degree is 74.3%; and 30.1% of the oasis’s area is supported by over-exploiting underground water and damaging the lower
reaches of the ecosystem. This result can be used as a guide in controlling and managing ecosystem risk in the research area.
