Assessing the regional ecological security: Methodology and a case study for the western Jilin province, China

摘要

Ecological security can be investigated in both broad sense and narrow sense. Because of the wide area and regionaldiscrepancy in influencing factors and ecological background, the investigation on regional environment hasn't beendone systematically. Assessment on regional security in fragile region is important content of sustainable development.The western Jilin Province is located in the semi-arid agro-pastoral interweaving belt (APIB), within which agricultureand animal husbandry interplay or frequently alternate with each other. Study on the regional ecological security ofthis region can be the scientific sport for protesting the regional environment and sustainability. This article sets up theStress-Feedback-Control model according to the interaction between human and environmental system, and assesses theecological safety degree in the western part of Jilin Province in year 2000, using compound model and Grid methodbased on GIS and RS. The Ecological Security Index (ESI) was calculated by multilayer synthesis with liner weightingfunction method, which divides the area into the following four different conditions: absolutely secured, secured, riskyand unsecured, regarding the change of environmental key point as the threshold value that varied under the stress ofhuman activity. The results show that most part of the investigated area belongs to the secured condition while the riskyand unsecured area distributed in the middle and western part of the investigated area. Furthermore, the condition in theeastern part is better than that of the western part. When talking about the ten counties in the region, absolutely securedcondition accounts for a very small percentage. The county that has the widest area of secured condition is Qian'an,while the smallest is Da'an. Tao'nan is the county that has the largest area of risky condition, which accounts for 43.08% of the whole county area; while Qian'an has the smallest area of risky condition, accounting for 1.56 % only. Theareas in unsecured condition in Tongyu, Zhenlai and Da'an have exceeded 10 % and they become the region requiringurgent treatment. The sequence of the regions regarding average security is Qian'an, Qianguo, Zhenglai, Songyuan City,Changling, Baicheng City, Fuyu, Taonan, Da'an and Tongyu, with the first one the highest and the last one the lowest.In study we also analysis the relationship between ESI and landuse change from 1980 to 2000 in order to find animproving method from landscape. The studying show that decreasing of grassland is most import factor influencing thecondition of the western Jilin province.