Ecological Vulnerability Assessment in the Middle and Lower Reaches of the Hanjiang River Basin

The purpose of this paper is to develop a framework of ecological vulnerability assessment, and to assess the ecological vulnerability by this framework in the middle and lower reaches of the Hanjiang River Basin. Based on the theory of cause - and - consequence, we proposed an indicator system of ecological vulnerability assessment at basin scale. Twelve indicators are selected to constitute the proposed framework of ecological vulnerability assessment. Based on the Landsat TM images acquired in 2000 and technical support of ERDAS & GIS software, an empirical study was carried out. The results of study show that the general characteristics of ecological vulnerability in spatial differences in the Hanjiang River Basin are as follows: the expression of ecological vulnerability is the most vulnerable in the plain regions, the middle vulnerable in hilly regions, and the weakest vulnerable in mountainous regions.