退耕还林区生态环境监测与评价——以陕西省为例

The monitoring and evaluation of ecological environment in the returned forestlands——a case study of Shaanxi province

为监测和评价退耕还林区生态环境,以陕西省为研究区,采用退耕还林前后MODIS数据产品,运用GIS空间分析方法提取坡度、植被覆盖度、生物丰度、土地退化指数等评价指标,建立评价模型来监测与评价陕西省生态环境状况。结果表明:空间上,退耕还林前,环境等级为优的面积较小,小部分集中于咸阳市、渭南市、宝鸡市和西安市,而环境等级为差的面积相对较大。到2015年,优的面积增加且分布渐趋集中。差的面积大幅减小,零星分布在延安市、铜川市、渭南市、西安市和宝鸡市。时间上,2000—2010,环境等级为优的面积呈下降趋势,2010—2015逐渐上升;2000—2015,良的面积不断下降,一般的面积不断增加,差的面积不断减少。

Shaanxi province is set as the research area to monitor and evaluate the ecological environment condition in the returned forestlands with the MODIS data products monitored during and after the implementation of the policy of returning farmland to forest.The application of GIS spatial analysis method extracts the evaluation indexes as Slope,Vegetation Coverage,The Abundance and Land Degradation,and the establishment of environment evaluation model monitors and evaluates the situation of the ecological environment in Shaanxi province.The results show that：（a）On the spatial scale,before the implementation of the Policy,the area at the optimal environmental level is small,solely distributed in Xianyang,Weinan,Baoji and Xi＇an whereas the area at the poor environmental level is relatively large.Till 2015,the area at the optimal environmental level increases and becomes concentratedly distributed while the area at poor environmental level decreases greatly,scattered sporadically in Yan＇an,Tongchuan,Weinan,Xi＇an and Baoji.（b）On the time scale,from 2000 to 2010,the area at optimal environmental level shows a downward trend,while from 2010 to 2015,it increases gradually;from 2000 to 2015,the area at good environmental level falls,the area at general environmental level increases continuously,and the area at poor environmental level decreases constantly.