锡林郭勒生物圈保护区草原生态系统服务间接价值动态评估

Changes of steppe ecosystem service values in Xilingol Biosphere Reserve of Inner Mongolia,China

草地是我国面积最大的陆地生态系统类型,对于维持我国北方的生态安全具有重要价值。北方草原的大面积退化已引起人们的极大关注。以内蒙古锡林郭勒生物圈保护区为研究区域,利用2个年份的遥感数据,结合地面样方调查,在GIS的支持下,绘制出草原退化空间分布图。选取草原生态系统在控制土壤侵蚀、减少土壤肥力流失、营养物质循环、CO2储存和O2释放方面的功能指标,对草原生态系统服务间接价值进行了动态评估。1985年和1999年草原退化面积分别为7190.9和7689.3 km2,占研究区总面积的67.19%和71.86%。2个年份草原生态系统间接服务总价值分别为28.24和26.75亿元,下降了5.28%,单位面积间接服务价值分别为2990和2830元,下降了5.35%。人类的过度放牧是导致草原大面积退化,生态系统功能降低和服务价值下降的主要原因。

Grassland ecosystem is the largest terrestrial ecosystem in China, and plays an important role in maintaining the ecological safety of Northern China. In this paper, the maps of steppe degradation in the Xilingol Biosphere Reserve of Inner Mongolia in 1985 and 1999 were drafted, based on remote sensing data and field survey. The changes of steppe ecosystem values were estimated by selecting the ecosystem functions such as soil erosion control, soil nutrient maintaining, nutrient cycling, C storage, and O2 production. The total valuation of the steppe ecosystem services in 1987 and 1999 was 28.24 × 10^8 Yuan RMB and 26.75 × 10^8 Yuan RMB, respectively, with a decrease of 5.28%, while the valuation of the steppe ecosystem services per unit area in 1987 and 1999 was 2.99 × 10^3 Yuan RMB·hm^-2 and 2.83 × 10^3 Yuan RMB·hm^-2, respectively, with a decrease of 5.35 %. The results indicated that owing to over-grazing, the steppe became more and more degraded, and the functions and ecosystem services of the steppe were also decreased. To restore the degraded steppe, keeping the densities of human and livestock under the carrying capacity of the steppe region should be the most essential solution.