The Eco-security Research Of Rapid Urbanization Region Based On The Efaa-yiwu Zhejiang Province As Example

Associated with the rapid urbanization in China and the spread of urban problems,a specific assessment of regional ecological security becomes increasingly important. Based on the ecological carrying principle, the Ecological Footprint Approach is designed to generate agrregate information on a population's demand on nature with its concise and clear calculation process.This methodology is proved to be a powerful tool of quantifying regional ecological carrying conditions by tracking the amount of natural resources a population uses and comparing it to the amount the ecosystems of a region can offer,moreover,to study the Ecological Security of a region. With the maturing of remote sensing technology, using remote sensing data for calculating the key parameters of the Ecological Footprint Approach Analysis have been made possible, which not only improves the precision of the calculation results and the depth of analysis, but also gives significance on the development of urban planning policy.Using Ecological Footprint Approach Analysis, this paper studys the ecological security of Yi'wu City in Zhejiang Province during its period of rapid urbanization (2000 -2007 years). The main contents of this paper are as follows: Combination of remote sensing technology, the author improves two key parameters of the Ecological Footprint Approach: the bio-productive area and the vegetation field factor, and obtains two years'land use data by interpret ting the TM image in 2000 and the SPOT image in 2007.They are all proved to have high degree of accuracy with the higher precision close to 90 percent, which is significantly superior to the conventional data source from the Statistical Yearbook. Compared with the actual situation, the field factors of cultivated-land, forest-land and grass-land also have a higher objective truth, which are estimated by the NPP results with the CASA model.Using those per capita consumption data from the Statistical Yearbook, the five bio-productive areas and the three vegetation field factors with remote sensing technology, and the other parameters already by hands in 2000 and 2007, the author estimates the Ecological Footprint in this period of Yi'wu city. The results show that, during this period the ecological carrying of Yi'wu city is deficit, and the per capita deficit expands from the 0.36gha per capita in 2000 to 0.64gha per capita in 2007.The ecosystem balance of Yi'wu city has been broken, and the ecosystem has been under a large pressure. According to the Ecological Footprint of each town in Yi'wu city, the author calculates their ecological carrying pressure index, and estimates the spatial distribution of ecological safety in Yi'wu city by standardizing the ecological carrying pressure index. The results illuminate that the ecological safety degree of Yi'wu city in 2000 is so low that nearly two third areas is at the"heavily unsafe"level, moreover, in 2007 the situation becomes worse that almost five sixth area reaches the"heavily unsafe"line.In order to further analyze the variation of the ecological safety in Yi'wu City, this paper assesses the ecological safety deterioration intensity in Yi'wu city by selecting a threshold value according to the standardized ecological pressure index changes during the year 2000 to 2007.Combined with the actual urbanization development of each town in Yi'wu city, some suggestions and measurements on lightening this area's ecological carrying pressure are proposed.