| It is of significant importance for regional ecological security and sustainable development to maintain and enhance the quality as well as the integrity of ecosystem services along with urbanization. Urbanization and ecosystem has its own regular pattern, and the coordination of urbanization and ecosystem services is not only affected by external factors, but also constrained by their internal law of development. Thus, the internal mechanism of urbanization and ecosystem services is firstly analyzed. The process and characteristics of urbanization in Yiwu City from1991to2010is analyzed by the framework of Urbanization Development Index, which is established by AHP and entropy method. The evolution of ecosystem services’value in Yiwu from1991to2010is studied according to Costanza and Xie Gaodi’s research. On this basis, the impact of urbanization on ecosystem services is revealed through correlation and regression analysis. The coordination between urbanization and ecosystem services is quantitatively evaluated by the Urbanization and Ecological Services Coordination Index. Considering the situation of reality, some countermeasures are finally raised from the perspective of maintaining and optimizing regional ecosystem services, holding the principle of "ecological priority, balanced development". The results are as follows:(1) The Urbanization Development Index of Yiwu surged by0.6248in1991to5.2038in2010, with an average annual growth rate of36.64%; The Population Urbanization Index rose from the0.2667to0.5977, which has a steady annual growth rate of6.21%, reflecting the "bottom to top" urbanization motivation. The Economic Urbanization Index surged to1.3867from0.1112, which has an average annual growth rate of57.35%, reflecting the positive interaction between urbanization and industrial agglomeration; The Landscape Urbanization Index rose to3.2194from0.2469, and the average annual growth rate is60.20%, which reflects the urban space is expanded from point to line and ranges in radiation, as explosive speed as well. The main problems during urbanization in Yiwu include the coexistence of overloading and inefficient use of urban space, eroding of industrial space to ecological space, and continuous increasing of ecological costs which constraints the sustainable development both in economy and society.(2) The total value of ecosystem services of Yiwu City is49.68×108～46.84×108Yuan, estimated by a typical ecosystem service value benchmark prices. The value of Provisioning Service is5.75X108～5.15×108Yuan; Supporting Service is14.52×108～13.98X108Yuan; Regulating Service is26.04×108～24.12×108Yuan; and Cultural Service is3.36X108～3.59×108Yuan, which account for about11%,30%,52%and7%respectively. The total value in2010has decreased by about5.7%than that in1990, while the contribution of forest ecosystems has increased from69.56%to73.86%, grassland increasing from7.28%to8.86%, farmland decreasing from15.59%to9.06%, river/reservoir decreasing from7.50%to4.58%, and urban&settlements increasing from0.08%to3.65%. So the functions and services of ecosystem have degradated and the quality of environment is reduced.(3) Ecosystem services derived from the functions of ecosystems, and the content and the number of ecosystem services are closely related to the types and patterns of ecosystems. The results of correlation and regression analysis between the Urbanization Development Index and ecosystem services have shown that different aspects of urbanization and ecosystem services are strongly related. Landscape Urbanization has visually reflected land use/cover changes, and has affected the content and quantity of ecosystem services through alteration in landscape patterns. It is a symbol and approach to the variation of ecosystem services. Population Urbanization is the inner and core driving force of changes in ecosystem services. Economic Urbanization affects the contents and constitution of ecosystem services. The development process of Yiwu City from1991to2010is evaluated by the Urbanization and Ecological Services Coordination Index. The results have shown that urbanization and ecological services are in a mild state of conflict during the past20years. And it is mild conflict, basic coordination, mild conflict, and mild conflict observed by4periods of five-years. So the development of urbanization and ecosystem services in Yiwu City is not well coordinated, and the pressures which the ecosystem bears are in an increasing trend.(4) Based on ecological economics and landscape ecology theory, combined with the characteristics and functions of Yiwu, suggestions are raised that the current Supporting Service and Provisioning Service should be protected and the Cultural Service and Regulating Service should be enhanced in future urbanization for better coordination between urbanization and ecological services. By adjusting and optimizing landscape patterns, eco-functional zoning helps to keep the Supporting Service and Provisioning Service to a stable level. Four ecological function zones that ecological conservation zone of southern hilly region, ecological control zone of northeastern low hilly region, ecological coordination zone of southwestern hilly plains region and urban settlements zone of middle plain region are divided according to the current situation of economy and society, considering the contents and distribution of ecosystem services of all towns (street offices), analysis of ecological sensitivity and critical resource capacity. Three types of ecological construction goals that ecological conservation, ecological control, ecological coordination are determined while future directions of development for each functional region are clarified.Containing a large number of vegetation and water bodies and other natural elements, the urban green spaces are the main source of Cultural Service and Regulating Service to the urban built-up area. Survey on the patterns and structure of urban green spaces in downtown of Yiwu which has an area of67.42km2is carried out. There is a total green area of815.39hm2in downtown of Yiwu City, and the ratio of green space is12.09%; the green coverage rate is13.70%, which means the overall amount of green space is poor. Various types of green space developed unevenly, parks accounting for44.83%, business green space accounting for22.83%, residential green space only accounting for18.09%, and protective green space accounting for only14.25%. The green spaces are unevenly distributed in downtown which resulted in limited affection. There are much more green spaces in the east than in the west. The artificial greenery has a poor ecological function because of monotonous plant species and simple community structure. In order to improve the ecosystem services of urban green space system, the pattern of green spaces should be completed firstly according to the functions of Yiwu City. The benefits of green spaces should be brought into play through combining green spots into range. The network of urban and rural green corridors should be established and improved to obtain a landscape pattern of "aggregate with outliers". The structure of urban green spaces should be optimized simultaneously, and the functional planting communities should be reasonablely designed. Native plants should be protected and regional plant communities should be restored and reconstructed during the growth of urban green spaces. The following conclusions can be drawn through these studies:(1) There is a certain interaction between the evolution of the process of urbanization and ecosystem services;(2) The functions and the ecosystem services of a city are closely related, and the content and quantity of ecological services will inevitably vary according to the city’s functions and projects;(3) Optimization and development of ecosystem services should also be combined with city functions, and different strategies of adjustment should be considered according to different ecosystem service types. The content and the number of ecosystem services should be able to meet the future needs of city development by means of landscape pattern adjustment and ecological construction. |
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