Comprehensive Assessment Of Habitat Suitability-Sensitivity-Ecological Risk In Ya’an Earthquake Area

The Ya’an earthquake area is characterized by vulnerability and environmental risk because it is located in the transition zone of the Sichuan basin and the Qinghai-Tibet plateau. This thesis focuses on the comprehensive assessments of the habitat suitability, the ecological sensibility and the ecological risk in Lushan county and baoxing county by use of 3S technologies. The thesis includes 3 parts, the detailed research contents and results are as following:(1) Firstly, this study evaluated the habitat suitability of Baoxing county by selecting total 16 driving factors such as terrain, meteorology, vegetation, geological disaster and so on. The results showed that habitat suitability increasing turned lower from southeast to northwest. The suitable, sub-suitable, unsuitable, worst suitable zones were 16.79%,26.93%,32.47%,23.81% of the whole area of Baoxing, respectively. The distribution area of the previous former two zones, with a height less than 2900 meter and slope no more than 30 degree in the sunny slope. The more suitable, sub-suitable zones concentrated in half-sunny slope, which was beyond the core area of the world heritage protected area and also was consistent with the distribution of population.(2) Secondly, this study assessed the ecological sensibility of Lushan county by choosing 6 driving factors such as average annual rainfall, terrain, vegetation, lithology, soil and so on.. The outcomes indicated that the ecological sensibility was higher in the northwest of study site, while the mid and southeast were lower. The areas of most sensitive and non-sensitive were 7.25% and 13.53% respectively, the areas of low-sensitive, mid-sensitive, high-sensitive were 23.63%, 25.25%, and 21.08%, respectively. Meanwhile, Lushan county was divded into 3 ecological functional zones from north to south, and are called biodiversity protection zone, agriculture and eco-tourism zone, eco-economic zone in turn.(3) Finally, this study built the ecosystem risk evaluation model of Lushan county based on the analysises of hazard-cause body, hazard-bearing body, exposure and vulnerability. The results showed that ecosystem risk decreased from south to north. The areas of lower-risk, low-risk, mid-risk and high-risk zones were 20.18%, 31.11%,28.78%,19.93%, respectively. The lower-risk and low-risk zones were located in forest and grassland ecosystems with high elevation, which have stronger bearing capacity to the interference because of diverse biodiversity, while the other zones distributed in the agro-ecosystem and the building land, and has a weak withstanding to the interference from the external world.