The Study On Land Carrying Capacity Of Chongming Island Based On GIS And Remote Sensing

The Chongming Island which lies in the Yangtze delta, where the agriculture is the primary and fundamental industry. The Island is relatively less influenced by human activity, and is thought to be full of most significance in its latent strategically space for further development of Chongming Island. In recent years, the Shanghai Municipal Government launched a strategic program to construct a sustainable Chongming Eco-island (CEI). How to develop economy but at the same time to protect ecological environment, has put the government and the policy-maker into a dilemma. To fulfill the construction of CEI, we encounter many questions such as what's the Chongming Eco-island. How many people the Island can bear? How many land resources the Island has leave for the further development needed? How to resolve the problem between the population growth and land decrease and degradation? But first of all, how much the ecological carrying capacity for Chongming Island is the first but essential question to the sustainable development and Eco-island construction for Chongming. It is a great challenge to researchers and decision-makers.In this thesis, the method such as production estimation model, crop production estimation with remote sensing data, field investigation and observation and statistical analysis was employed, in support of remote sensing, Geographical Information Science and Global Positioning Systems which so-called "3S" techniques, to quantify and analyse the interactions between the population, food, land resources and life quality. We aim to address that (1) how about the current status of land resources in Chongming island; (2) the land production potential in different conditions; (3) the population carrying capacity in Chongming island; (4) the comprehensive carrying capacity of land resources for Chongming island. Finally the optimization of landuse type and composition and the reservation of land for further development were also discussed. The findings are as followed:(1)The results from the landuse type extracted from aerial photos of Chongming Island acquired in 2005 showed that the total area of the three Chongming Island is about 1590.6km~2, in which the agricultural land area is 911.19km~2, the water area reaches 420.47km~2, both account for almost 83.72% of the total area. That is indicative of mono-landuse type in Chongming Island.(2)The proportion of agricultural population and agricultural lansuse type account for 72.18% and 57.29%, respectively which demonstrate that the agriculture is the basic and pillar industry in Chongming island.(3)According to the average grain consumption per capita and the lower land carrying capacity basing upon the present land productivity, the standard of living in Chongming Island has achieved confortable level in 1999 and surpassed well-off level in 2004, but has not reached wealth at present. That is to say, the current population carrying capacity was overloaded if in terms of wealthy standard of living.(4) Based upon the potential climate production we calculated. The upper population carrying capacity is approximately 24 persons per hectare per year. So there is great growth space of 65.7% for the population in Chongming Island.(5) The use efficiency of annual mean potential climate productivity is in the range of 50% to 65% according to the estimation results of Miami model, Thornthwaite Memorial model and CASA model, which demonstrates that there is great potential for land productivity promotion in the future.(6) The actual area of arable land is lower than the demand in 2001, and it is projected that the arable land demands will be satisfied at 80% in future 15 years in terms of the present land productivity;(7) The estimated minimum productive land area demonstrated that there are approximately 22,092.8hm~2 land area can be used to further development on the premise of that keeping the people in the wealthy standard of living and the land productivity can reach the potential climate production;(8) The performance of modified CASA model in estimation of land productivity and the method of crop estimation with remote sensing data for large area demonstrated that the two ways is robust and reliable in the estimation of land productivity support with 3S techniques. But better quality data and more data quantity should be needed to further enhance the accuracy of the estimation in the future.