Study On Land Cover Change And Ecological Response In Chongqing

The changes of land use/land cover have transformed the structures,functions and ecological status of the region's ecosystem,which have some influence on the development of ecological environment and social economy.The urbanization process has been accelerated,and a large scale of population has transferred to the western part of Chongqing since Chongqing became a municipality.It makes a great difference to the distribution situations of land structure and ecological environment between the northern and southern regions,and the eastern and western regions.With ecosystem service value and ecological security index being the effectors,this article analyzes the correlations among ecological service value variation tendency,ecological security pattern and land use/land cover based on Chongqing's land use structure and ecological environment conditions,which is of great significance to improve the ways of land use,optimize the layout of land structure,better the stability of ecosystem and improve the ecological environment.The main conclusions are as follows:The researches on land use/land cover changes of Chongqing during 2000 and 2015 find out that Chongqing's land use changed quickly,transformations among different types of land use were large;on the other hand,land use changed slowly and reached a steady state during 2010 and 2015.As a whole,transformations among different land use types were obvious;forestland areas expanded;the water areas increased then stabilized gradually;mass cultivated lands and grasslands transformed into forestlands and construction lands;the ecological environment in research area was improved gradually.During the whole research period in Chongqing,there was a small change in landscape indexes and a high abundance of landscape types,but a high degree of landscape fragmentation.Based on Chongqing's fundamental situation,the ecosystem service value has been revised per unit area,which mainly include coefficients of four service functions,being classified into water conservation,food production,gas regulation,and climate regulation.In the meanwhile,partial service functions of construction lands have been added.As a result,the ecological service value trend after the revision is in line with the specific situation of Chongqing by making comparison of the ecological service value between equivalent factor before revision and that after revision.The total value of ecosystem services of Chongqing was accelerating from 2000 to 2015 with its high value areas mainly distributed in the Yangtze River Basin,the Reservoir Area of Northeastern Chongqing and the Mountainous Area of Southeastern Chongqing and its low value areas of mainly concentrated in the main urban areas and the built-up areas of districts and counties,which have been expanding year by year.The increase in ecosystem services is due to the fact that a series of environmental projects gradually come into ecological effects which led to an increase in forestlands,and water areas increase resulting from the official operation of the Three Gorges Reservoir.In terms of different ecosystem service functions,the service value from soil formation and protection in Chongqing takes up the most;on the contrary,the service value from food production takes up the least.The Grain for Green Project was implemented in Chongqing in 1998.The following Forest Engineering Project,the Natural Forest Protection Project,and the Yangtze River Ecological Barrier Project have played a crucial role in improving the ecological environment.Due to acceleration of urbanization which brought a large number of people into the main city in early 2000,the internal structure of Chongqing was destroyed and the ecological environment of western part of the main city changed adversely with an extremely unstable ecological pattern and relatively small ecological security index.On the contrary,the ecological environment of northeastern and southeastern Chongqing where there exists a vast forest cover area has been further improved with the implementation of the ecological projects,in which various ecological protection policies have come into effect gradually and soil erosion and rocky desertification have been further bettered.What's more,the ecological security index in these regions has increased year by year with ascending environmental quality.