Eco-environmental vulnerability evaluation in mountainous region using remote sensing and GIS—A case study in the upper reaches of Minjiang River, China

Abstract

The upper reaches of Minjiang River-valley, located on the eastern edge of Qinghai–Tibet Plain, is characterized by the complex distribution of hills and valleys. It is a typical and key mountainous region with apparent upland ecosystem vulnerability and sensitivity according to National Eco-environmental Renovating Scheme of china. In order to analyze eco-environmental vulnerability, remote sensing (RS) and geographical information system (GIS) technologies are adopted, and an environmental numerical model is developed using spatial principle component analysis (SPCA) method. The model contains nine factors including elevation, slope, accumulated temperature, drought index, land use, vegetation, soil, water-soil erosion, and population density. Using the model, the integrated eco-environmental vulnerability index (EVI) of study area in 1972, 1986, and 2000 are computed. According to the numerical results, the vulnerability is classified into five levels: potential, slight, light, medial, and heavy level by means of the cluster principle. The eco-environmental vulnerability distribution and its dynamic change in the last 30 years from 1972 to 2000 are analyzed and discussed. The results show that the eco-environmental vulnerability in study area is at medial level, and presents apparent vertical-belt distribution, and that driving forcings of dynamic change are mainly caused by human social economic activities and the contribution of late national eco-environmental protection policies, such as Natural Forest Protection and Grain for Green. According to these results, the study area is regionalized into three sub-regions, which may serve as a base for decision-making for eco-environmental recovering and rebuilding. The results of this study indicate that the method that integrates RS, GIS, and the SPCA to evaluate eco-environment vulnerability in mountainous region, cannot only distinctly represent the input subject spatial distribution of mountain vertical-belt feature, but also respect the river-valley as a whole system.