Evaluating the effects of eco-environment conservation projects in China by remote sensing technology

National key projects of eco-environment conservation have been carried out to combat the environmental degradation in the fragile ecological zone in China since 1998. To evaluate the project´s effect on eco-environment restoration, five cases, locating in different eco-environmental zones and representing the different types of practiced measures, were selected to map land cover for each sample area, respectively, using Landsat TM images in 1997 and 2002. The mapping coverage of each sample site was confined within the overlaying extent of two images with the same path and row. And then the land cover changes were detected using overlaying technology in GIS. The results show that the land cover changes of each case site except for the site E located in the northeastern China characterized by farmland decreasing and natural or seminatural vegetation increasing, and that a serious of practiced measures adopted by the conservation projects have an effect on the rehabilitation of ecological environment.