Valuation Of Vegetation Ecological Services In Vulnerable Ecological Region

Unreasonably long-term natural resource development of human beings has brought about a series of eco-environmental problems. Basic structure and native function of ecosystem in different special scales were disturbed and destroyed, which led to the formation of frangible ecosystem of ecological services. Frangible ecosystem is greatly embodied by degradation and ruin of vegetation. Evaluating ecosystem services and the importance of vegetation is the basis to restore and rehabilitate frangible eco-environmental area. In this thesis, based on literature review of the origin, development and tends of ecosystem services research, analyzed effect of human beings activities on regional ecosystem services. Meanwhile, both of the connotations and valuation methods to vegetation ecological services were studied systematically, and value of vegetation ecological services was evaluated on Minqin oasis in arid desert region and the north semi-arid regions of the Yuzhong in Loess Plateau. According to valuation, many suggestions to restore and reconstruct of vegetation ecological services in vulnerable ecological region were proposed. The main contents are as follows:(1) The connotations of vegetation ecological services were discussed. According to the characters of circumstance and cover with vegetation in the region, the typical vegetation types in terrestrial ecosystems, including forest, grassland, cropland and desert plants, have very importance ecosystem services. Forest vegetation not only supply man with the production of ecosystem goods such as food, timber and pharmaceuticals, but also perform fundamental life-support services, including the soil retention, water-holding, wastes treatment, nutrient cycle, carbon dioxide fixation, oxygen production, climate regulation, soil formation, environmental purification, production and maintenance of biodiversity, disturbance prevention and windbreak function. Grassland vegetation and farmland plantshave the similar ecological services, but the levels are different. Ecological services of desert plants are special as they have very important value of scientific research, letdown wind speeds, prevention disturb of wind and windbreak function.(2) Based on literature colligation of valuation methods of ecosystem services, valuation methods on ecosystem services value unit area of Chinese terrestrial ecosystem by Gaodi Xie etc. was summarized. Meanwhile, the new means for verifying the sensitivity of value coefficients were introduced and improved through using the concept of elasticity coefficients on economics. The vegetation ecological services in the study area were estimated by "ecosystem services value unit area of Chinese terrestrial ecosystem" and the economic value of food production per hectare was supplied by cropland ecosystem. The veracity of the value coefficients and representative of vegetation types was tested by the sensitivity of value coefficients.(3) Several vegetation types in the Minqin desert oasis, including natural forest, artificial forest, natural grassland, artificial grassland, cropland, orchard, desert plants, were studied. The value of vegetation ecological services in Minqin desert oasis was estimated by "the table of equivalent weight factor of ecological value of ecosystem services of China", and the economic values of food production per hectare was supplied by cropland ecosystem and vegetation area in 1983, 1993 and 2003. The results showed that the value of vegetation ecological services in Minqin Oasis was 5.22><109 Yuan/a in 2003, and 3.02xlO9Yuan/a in 1993, and 2.22x 109Yuan/a in 1983, and the ecological value of artificial forest had the most roles of vegetation ecological services in Minqin desert oasis.According to the results of valuation, we think of the key measures to preferential assured vegetation water requirement, restored degenerative natural forest and artificial forest, and natural grassland in order to restore and reconstruct of vegetation ecological services in theMinqin desert oasis area.(4) Several vegetation types in north semi-arid region of the Yuzhong, including artificial forest, natural grassland, artificial grassland, cropland, desert plant, were studied. The value of vegetation ecological services in north Yuzhong semi-arid region was estimated with "the table of equivalent weight factor of ecological value of ecosystem services of China", and the economic value of food production per hectare was supplied by cropland ecosystem and vegetation area in 1983, 1993 and 2003. The results showed that the value of vegetation ecological services in north Yuzhong semi-arid regions was 15.98* 107Yuan/a in 2003, and 13.32xl07Yuan/a in 1993, and 7.69xlO7Yuan/a in 1983, which is about 11.3 times that of the production in 2003, and 10.8 times in 1993, and 9.1 times in 1983. On the one hand, the results showed vegetation ecological services are existent in north Yuzhong semi-arid region;on the other hand it fully reflected unbalance between "ecological productivity" and "economic productivity". The ecological value of natural grassland was the most roles of vegetation ecological services in north Yuzhong semi-arid region.According to the results of valuation, suggesting the emphases measures must to establish the vegetation systems of grassland restorations and appropriate plant shrubbery in order to restore and reconstruct of vegetation ecological services in north semi-arid region of the Yuzhong lied in Loess Plateau.(5) With restriction of natural condition and resources, restoration and reconstruction of vegetation ecological services in the vulnerable ecological regions should still pay attention to "naturalness" of vegetation and the key factors which affect vegetation ecological services, including the vegetation water requirement, ecological compensation mechanism, and ways of restoration and reconstruction of vegetation, protection and maintenance of old vegetation, invasions of exotic species and transform of ecosystem services market and so on. SomeFramework suggestions were put forward, which is including adjusting measures to local water resource, constructing diversified mechanism of ecological compensation and products market of ecosystem services under national macro-management on restoration and reconstruction of vegetation ecological services.(6) According to the natural condition and character of social-economic in the north semi-arid region of the Yuzhong in Loess Plateau, we have done the restoration tests of vegetation such as natural restoration of vegetation, artificial restoration of vegetation, and the effect of shrubbery cut down in the technological demonstration project of comprehensive ecological agriculture. The purpose of tests consists in exploring the effectual models for vegetation restoration in parallel with improving of regional social-economic development.The studies showed that countermeasures and appraisal ways of two kinds of ecological areas were made by quantitative research results. It is laid an academic foundation not only for restoration and rehabilitation of vegetation ecological services in vulnerable ecological regions but also for sustainable development of eco-economical system.