Study Of Temporal Dynamics On Ecological Carrying Capacity Of Land In Shanghai City

Ecological footprint as a measure of the degree of sustainable development of bio-physical methods, from the man and the relationship between development and ecological environment, starting by tracking the area of biological resources and energy consumption, material flow will be transformed into a variety of essential biological productive land area, accounted for the formation of a global, national, regional, and household and individual use of the simple framework of natural capital. The method by measuring the gap between the human ecological footprint and ecological capacity of the region to determine whether the ecological carrying capacity is within the scope of the ecological carrying capacity in the region to the assess sustainable development. Since the method is easy to understand, analyze visual and operability, it is widely used measure of ecological sustainable development.Based on the ecological footprint method, using the spatial information techonology such as RS and GIS, the ecological footprint and ecological capacity of 1987, 1997, 2007 was calculated and analyzed, and three periods of ecological footprint pressure, supply of ecological carrying capacity and ecological deficit of spatial pattern change were analyzed. In the ecological carrying capacity calculations, the use of RS technology in 1987, 1997, 2007 TM image interpretation, access to the land use data of three periods in Shanghai. In addition, in order to accurately reflect changes in regional ecological productivity, by using the method of the calorific value the yield factors of various types of land of three times were calculated. In summary, this paper by analyzing temporal and spatial variation of ecological force of land of the three periods in Shanghai, the following main conclusions were drawed: (1) The production capacity of various types of land in Shanghai is higher than the world level. In the three years of 1987,1997,2007 , the average yield factor of land was 3.36, woodland average 2.12, grassland 11.07, water 44.71 , construction sites is 3.36, indicating that the productivity of the land in Shanghai are higher than the world average level.(2) The per capita ecological footprint of Shanghai from 1.7565ha in 1987 increased to 4.5465ha a in 2007, rapid growth of ecological footprint; calculated data for three years, Shanghai has been in a state of ecological deficit, from 1.3479 in 1987 ha to 4.283ha in 2007, a serious deterioration of ecological deficit, indicating that Shanghai is in a state of non-sustainable development, people's demand for ecosystem services has exceeded the carrying capacity of the ecosystem.(3) In addition to the ecological footprint of farmland and forest land downward, other types of ecological footprint were in growing trend. Fossil fuels in the largest proportion of the total land, and ecological footprint grew the most obvious trend, indicating that urban social and economic development, a substantial increase in the demand for energy. The growth of land for construction is also more evident that the acceleration of urbanization, housing and road construction for land was increasing.(4) From 1987 to 2007 in Shanghai, per capita ecological footprint, per capita ecological deficit, per capita ecological carrying capacity and the dynamic change of all were analyzed to find the overall per capita ecological carrrying capacity show a downward trend, but the decline is not very obvious, the growth of per capita ecological deficit and the growth of the per capita ecological footprint were in the same trend, that is, the increase in per capita ecological footprint is the direct cause of the growth of the ecological deficit.(5) By the analysis of the pressure on the ecological footprint, ecological carrying capacity supply, ecological deficit of spatial pattern in 1987, 1997, 2007, we can see than the spatial pattern on ecological carrying capacity distribution more uniform, the change rate is not very obvious with the time, the ecological footprint of high pressure concentrated in the central area of the city, from 1987 to 2007, areas of high ecological footprint pressure of expanding the spatial distribution and ecological deficit and ecological footprint pressure trend is basically the same.In summary Shanghai was in the eco- deficit state in the nearly twenty years, and the ecological deficit was in the growth trend with the risk of ecological sustainability increasing.(6) The million GDP eclolgical footprints of Shanghai show a downward trend. Ecological footprint of the million GDP in 2007 was 0.6931ha / million, less than the national 1.785ha / million, that is, the output of the same unit, the ecological footprint of consumption in Shanghai is less than the national average. With the million GDP eclolgical footprint decline, the ecological footprint of Shanghai has achieved rapid economic development, than mean the economic development that was faster than the unit occupied by the ecological footprint of the amount of GDP.