河西走廊瓜州绿洲生态系统稳定性评价与生态风险防御对策

Ecosystem Stability Assessment and Defense Countermeasures of Ecological Risk for Guazhou Oasis in Hexi Aisle

瓜州绿洲属于国家级极端干旱荒漠自然保护区,光热资源丰富,但草场退化、土地沙化、土壤盐渍化等问题严重。以1991-2007年瓜州县统计数据为基础,从自然资源状况、环境压力、社会经济状况三方面建立瓜州绿洲生态系统稳定性评价指标体系,用变异系数赋权法确定指标权重,运用模糊数学评价法进行综合评价。结果表明:瓜州绿洲生态系统处于Ⅲ级,即潜在不稳定状态。并认为水资源需求压力大、气候极端干旱、草场退化、土地沙化、土壤盐渍化问题严重及城镇化水平低是造成研究区生态系统潜在不稳定的主要原因。针对以上问题,本文提出了瓜州绿洲生态风险防御的对策。

Guazhou Oasis is state-level nature reserve, rich in light and heat resources, but the grassland degradation, desertification and salinization are serious. Based on the date recorded by Guazhou County Forestry Bureau and Guazhou Statistical Yearbook during the period of 1991-2007, Evaluation index system of the ecosystem stability in Guazhou oasis is developed, which takes natural conditions, environment pressures and socio-economic situation into consideration. The weighting values of the relative importance of the indexes are established by using the coefficient of variation method. The comprehensive evaluation is completed by fuzzy math method. The result shows that the study area is potentially unstable. It points out that this result is due to water shortage, climate extreme drought and grassland degradation, desertification and soil salinization serious, the low level of urbanization. Finally, the defense countermeasures of ecological risk are presented.