The Evaluation On Land Ecological Bearing Capacity Of Nanchang City Based On Grid System

Sustainable development is the core issue of environment and development issues, previously, people in the pursuit of rapid economic development, the use of natural resources greatly exceeds the renewal capacity of resources, ecological environment is deteriorating, a serious threat to human survival and development. One important way to study the ecological carrying capacity as the evaluation of sustainable development, based ecology, environmental science, resource science and economics on the comprehensive assessment of human activity is within the scope of the Earth can sustain, as formulated human decision making on the basis of sustainable development and achieve eternal Earth’s environment and human society. Being aware of the ecological carrying capacity is the key to the problem, the scholars from all over the world does the positive exploration. To date, most studies of ecological carrying capacity is based on administrative areas as an unit, to explore the ecological carrying capacity of regional overall situation, the lack of the analysis and evaluation of ecological carrying capacity within administrative region. Combination of the land use, and using the emerging ecological carrying capacity of GIS technology in the search for a small scale will be a brand new perspective. Taking Nanchang as the study area, interpretation of 2012 TM remote sensing image are extracted the land use data, united the data of land use of the year of 2000, 2005 and 2010, used GIS grid technology method, Urban and rural population spatial distribution model are established respectively. On this basis, using the ecological footprint method, three levels( the distinct level,the county level and the grid level)of ecological environmental carrying capacity evaluation explored the ecological environmental carrying capacity from 2000 to 2012 in the dynamic change of process, analyzed the reasons of the carrying capacity of the ecological environment change, and in view of the present ecological environmental carrying capacity in the study area situation put forward some suggestions and countermeasures, like the control of population scale, the pass of ways of land use change, etc.The main conclusions are as follows:(1) In the types of land use in Nanchang, the cultivated land is the most widely distributed, followed by woodland, water land and land for construction purposes. From 2000 to 2012,with the overall declining of cultivated land and forest land area, total construction land area is rising, and the increase in the form into the expansion of the "pie" type. The trend of cultivated land and forest land converting into construction land is obvious.(2)In the simulation of the spatial distribution of population, the urban population distribution mainly relate to the area of construction land and its distance to the city center. The spatial distribution of urban population showed a trend of envelops by decreasing outside introversion, the more closer to the city center, the more densely populated, this is in the Nanchang city(including 5 area) performance is particularly obvious. And in the rural population distribution of rural residential areas, the type of rural land use of cultivated land and forest land are related, the most significant relevance is rural residential areas, the correlation coefficient is 26.663,,the correlation coefficient of cultivated land is 3.584, and the correlation coefficient of woodland is the weakest, the correlation coefficient is 0.403. In the simulation results of the spatial distribution of the whole population in the study area, the simulated population less than statistical population by 24900 people, basically reached the requirements of the total population of simulation.(3)In 2012, the per capita ecological footprint of the study area is 1.295, the per capita ecological carrying capacity is 0.460, the ecological carrying capacity difference between supply and demand for 0.835, ecological environmental carrying capacity evaluation status called ecological deficit. When divided into counties ecological environmental carrying capacity evaluation, Nanchang(including 5 area) characterized by ecological deficits, while the Nanchang county, Xinjian county, Jinxian county and Anyi were characterized by ecological sensitive, the Nanchang county had the highest sensitivity, Anyi borne lowest sensitivity. On the grid level of evaluation of carrying capacity of ecological environment in the studied area, the ecological sensitive area and the ecological deficit area is not to cover the entire administrative region. The ecological deficit area, ecological sensitive area, ecological flat area and ecological surplus area distributed over the entire study area. The area of ecological deficit and ecological sensitive was corresponding to the distribution of construction land on the map, ecological flat area is corresponding to the distribution of cultivated land on the map, ecological surplus area corresponding to the distribution of woods region and waters.(4)From 2000 to 2012, within the scope of the study area, the most obvious change of ecological environment carrying capacity is the range of ecological deficit area, which expands gradually from Nanchang city in 2000 small scale to a wide range of ecological deficit area in 2012. Not only the original ecological deficit area was pie-like extensions, the downtowns of Jinxian and Anyi, which’s status of ecological carrying capacity were in sensitive or flat once, also presents the expansion of the area of ecological deficit from point to plane. At the same time, within the scope of the study area, ecological deficit area and ecological sensitive area spread with the extension of network and spread.