Study On Land Use Change And Its Influence On Land Ecological Security In Changsha City

In recent years, people of Changsha constantly put more emphasis on the usage of the land. This leads to a set of serious problems in eco-environment, The more prominent contradiction between human and land. As a result, the sustainable development of Changsha’s economy and society has been intruded on. Based on the above case, the author of this paper, taking Changsha as the research object, analyses the affect of the land use change on its land ecological security. A brief introduction of the content and conclusion of this paper is as follows.The first part is on the data resources and data processing. The primary data of remote sensing interpretation in Changsha are selected from remote sensing images of1995,2002and2009LANDSAT5TM. They are preprocessed, classified and post-classification, by means of ENVI4.8and ARCGIS9.3. Three classification charts of land usage are thereafter obtained.The second part is on the change of land usage. The analysis develops from five aspects, namely changes of amount, changes of structure, changes of speed, changes of extent and transfer. The research shows that as for the changes of land use structure, except construction land and water area, the rest demonstrate reduced percentages during the research course and yet the information entropy of land use structure is on a continuously up trend; as for the changes of land use amount, in the past15years, the construction land and water area have maintained positive growth while farmland, forestry and unutilized land have been negative growth; as for the changes of land use speed, from1995to2009, the comprehensive dynamic degree of the five kinds of land is0.04, among which unitary land use dynamic degrees of construction land and unutilized land, both0.13, take the lead; as for the changes of land use extent, the index raises in a narrow range; as for land transfer, farmland ranks first in roll-in and roll-out and then comes forestry.The third part is on the effect of land use changes on land ecological security. In this paper, land ecological security indicator system is established, on the basis of P-S-R conceptual framework pattern and15index illustrating pressure, status or response. The index are, according to the practice of Changsha, devided into five levels. Then the unascertained measuring model and Entropy value method are adopted to evaluate land ecological security of the city. The result indicates that the land ecological security of Changsha fluctuates, with its evaluation score raising from2.4005in1995to2.9888in2009and its evaluation level from the fourth to the third. The overall land ecological security of pressure subsystem tends to decrease, while that of response subsystem increases step by step, with its evaluation score ascending from2.0240in1995to4.4860in2009.The final part of the paper puts forward countermeasures and suggestions on account of the research conclusion. At the beginning, reduce the pressure on land ecology. Secondly, adjust industrial structure and arrange the land use of each industry as a whole. Then, set up compensation mechanism for land ecology. Last,establishment the ecological function zoning of land.