Study On Ecological Capacity And Environment Evaluation Of Qingyang, Gansu

Qingyang city lies in the Loess Plateau of eastern Gansu where energy resources base construction was promoting, while soil erosion, land desertification, degeneration of grassland, soil salinization and water environment depravation tended to worse. Based on regional natural resources and social development, ecological capacity, recourse and environment capacity, ecological security, ecological sensitivity, ecosystem services value assessment were evaluated with principal component analysis and analytic hierarchy process, by which some suggestions on ecological security construction were put forward. The main conclusions can be summarized as follows.1)The ecological footprint (EF) and ecological capacity (EC) of Qingyang during 2001 to 2005 were calculated, and the historical change pattern and the causes of EF and EC in the past five years were analyzed. A forecast model was established to foretell the sustainable development tend of Qingyang. The results showed that the average personal EF gradually increased from 1.12 ha to1.34 ha during 2001 to 2005, whereas the average personal EC declined from 1.13 ha to 1.11ha. It can be concluded that the EF and EC in Qingyang developed contrarily. In 2001 the ecological surplus was 0.02 ha, and in 2002 ecological deficit arose, which rose to 0.23 ha by 2005. The model forecasts that the average personal EF and EC would be 1.33ha and 1.03 ha, and the average personal ecological deficit would reach to 0.30ha in 2010. The overall result indicates that the ecological environment in Qingyang is unsafe and the present developing model is not sustainable.2)By establishing recourse and environment capacity assessment indicators that are suitable for the regional environment of Qingyang city,The integrated index of recourse and environment capacity was calculated using the multi-criteria, on which weight was selected by principal component analysis method. The result showed that there were difference in resources and environment capacity among different county.3)Based on“Pressure-State-Response”model, the indices system was established and ecological security of Qingyang was evaluate with analytic hierarchy process. The analysis showed that the ecological security index of Heshui is highest (0.66), the ecological security state was fine, the ecological security level was comparatively safe. The ecological security index of Huachi, Ningxian, Zhengning and Xifeng was medium (0.4-0.6), the ecological security state was general, and the ecological security level was warning. The ecological security index of Zhenyuan, Qingcheng and Huanxian is low (0.2-0.4), the ecological security state was poor, and the ecological security level was dangerous.4)The sensitivity of soil to erosion and to land desertification, and sensitivity of water environment and habitats were analyzed for a sample city,Qingyang city of Gansu province. Then the integrated ecological environment of Qingyang city was assessed, based on which the whole environment of Qingyang city were classified into four grades as: insensitive, moderately sensitive, highly sensitive and extremely sensitive. Nevertheless, proper environmental protection countermeasures and industry adjusting strategies should adopted against the regional situation of each grade so to achieve the sustainable development of Qingyang city.5)According to images and statistics material of Qingyang county territory in 2005, the value of ecosystem service such as support, moderation and civilization of five types of ecosystems are calculated and evaluated by using physical and value assessment methods for ecosystem service functions. The results show that the total value of ecosystem service is grassland>forest>farmland>orchard>water area. Service value of per unit area is forest land>garden plot>grassland>farmland. Various value of ecosystem service is water conservation>soil conservation>air conditioning>nutrient cycle>clean environment. The total value of ecosystem service of county territory is Huanxian >Heshui>Huachi>Zhenyuan>Ningxian >Qingcheng>Zhengning>Xifeng.Service value of per unit area is Ningxian >Heshuixian>Zhengningxian>Huachixian>Xifeng>Zhengyuanxian>Qingchengxian>Huanxian. Ecosystem service functions are mainly about water conservation and soil conservation in Qingyang. Ecosystem services value of forest ecological districts is the highest, and the contribution rate of forest ecosystem is the greatest in temperate and cool humid, cool semi-humid low hilly of the eastern,. Ecosystem services value of agro-ecological zone is the second, and the contribution rate of grassland and forest land is the greatest in temperate and semi-humid regions of south-central in plateau gully. Ecosystem services value of agriculture-nomad area is the least, and the contribution rate of grassland ecosystem is the greatest in the cool arid and semi-arid hilly of the northwest6)In order to solve the key problem of ecosystem safety in Qinyang City, the methods are presented to construct ecosystem safety.In ZiwuLing forest region,the following methods is applied,namely primarily optimizing patterns;actively implementing natural forest protection engineering;accelerating the speed of returing cultivated land to forest;constructing economic forest and forest for water and soil conservation according to the local situation. In the Gullied Loess Plateau , human intervention should be prevented;and the techonology system for drought-resistence agriculture should be adopted to improve resisting natural calamities in agriculture.In the Loess Hill-Gullied Areas, the primary measure is to reduce human activity,and enhance water and soil conservation by biological control measure and engineering measure.In windy desert area of north Huan county,husbandry activities should be restricted and desertified land ought to be constructively rehabilitated to elimilate dynamic factors to promote soil desertification.In the exploited oildom and the oildom to be exploited,pollution should be greatly reduced to ground water and near-surface soil.As to polluted ground water and near-surface soil, biological measure should be employed.At present, new export-oriented exploited oildom takes precautions to preclude pollution from the origin.