基于遥感和GIS的农牧交错带生态资产定量评估——以宁夏盐池县为例

Quantitative Estimation of Ecological Assets in Farming-pasturing Ecotone Based on Remote Sensing and GIS——A Case Study in Yanchi County,Ningxia

自2003年宁夏全境实行禁牧政策以来,处于农牧交错带的盐池县生态与环境变化受到广泛关注。利用2000年、2005年、2010年TM/ETM+和MODIS NDVI数据,定量反演生态参数,计算3个时点的生态资产,评估禁牧政策的环境影响。结果表明:盐池县生态资产总值分别为1.62×108、2.15×108、2.70×108元;生态系统服务功能中水土保持价值比重最大,其中贡献最大的土地利用/覆盖类型为占研究区总面积最大的草地;单位面积生态资产价值最高的为旱地,10 a间生态资产总体呈递增趋势,东南部黄土丘陵区增幅明显,说明过去10 a来禁牧政策有助于生态资产的增加,环境质量总体趋好。

Yanchi County in Ningxia Hui Autonomous Region, China is located in an area where the ecological environment is vulnerable, and it is a typical farming-pasturing ecotone in north China. In the county, the ecological conservation and environmental protection is paid great attention to at all levels since the grazing-ban policy was put into practice in Ningxia in 2003. In this study, the TM/ETM^＋ and MODIS NDVI data were used to retrieve the ecological parameters and estimate the value of ecological assets in the county, and it was tried to provide an evidence for the ecological conservation, environmental protection and substantial development. The results show that the gross value of ecological assets was 1.62 ×10^8, 2.15 × 10^8 and 2.70 × 10^8 yuan RMB in 2000, 2005 and 2010 respectively. In ecosystem service functions, the value proportion of soil and water conservation was the highest, in which the contribution of grasslands with the largest area was the highest in the land use/cover types. The value of ecological assets of rain-fed farmland per unit area was the highest. The total value of ecological assets was in an increase trend in recent decade, especially in the loess hilly region, which demonstrated that the local ecological and environmental quality was trended to improvement under implementing the grazing-ban policy.