| With the deepening of the human activities, changes of ecological environment caused by land use/cover is becoming more and more intense, and the contradiction between land and population is more serious and critical. Understanding the laws, characteristics and process of the land use/cover change, and clearing the response of the ecosystem services value to cover change has important academic value and practical significance to guide the production and living of people, promote the adjustment and optimization of land use policies, and strengthen the protection of ecological environment.This article taking Qianwei County as the study area which is a typical hilly area in Sichuan, using the remote sensing image data in 1990,2002 and 2013, through geometric correction, radiometric calibration, atmospheric correction, image enhancement and image cropping, complete the pretreatment of remotely sensed images. According to the land use/cover classification principles, establishing the classification system and the key of image interpretation, the cover types of land use in this county can be divided into 6 classes:cultivated land, farmland, forest land, grassland, water body, construction land and unused land. Using supervised classification and unsupervised classification method, realized the interpretation of three periods remote sensing image data in the studied area, get the three periods maps of land use/cover types in Qianwei County, and obtain the objective change data of land use/cover in the study area. Under the support of modern geographic information technology ENVI5.0 and ARCGIS 9.3, using models such as the land use dynamic degree, information entropy, the degree of land use, transition matrix and the change of gravity center to analyze the spatio-temporal change characteristics of land use/ cover types of Qianwei County during1990-2004. Then, according to the actual situation of Qianwei make up the equivalent factor table of ecosystem services value, using the ecosystem service value assessment model realize the quantitative evaluation and calculation of ecosystem service value of Qianwei, and analyze the differences of space change of ecosystem service value of the three land use comprehensive functions, towns and industrial development area, the agricultural industry development area and ecological industry development area. Finally, through the calculation of correlation coefficient of land use and ecosystem service value and the variation contribution rate of ecosystem services, analyze the response characteristics of ecosystem service value for the land use change, and put forward the optimization strategy of land use in Qianwei. The results of the study are as follows:The space-time variation characteristic of land use/cover change in Qianwei County was obvious. From the point of view of time sequence, land use/cover conversion is frequent, less arable land and the increase of forest land is the main aspects of change. From 1990 to 2013, cultivated land cut down 8813.68 hectares, and the forest land area aggrandize 6951.05 hectares, the proportion rose from 39.12% to 44.20%. Construction land rise to 2158.75 hectares during the 24 years, the proportion rise from 5.07% to 6.64%. Seen from space, the characteristics of the change of gravity center of cultivated land and forest land is obvious in nearly 24 years. The emphasis of cultivated land is moving to the center of agricultural industry development area, and the focus of the forest land is moving to ecological industry development area. The core of construction land mainly move in sort distances near the county. The emergence of that trend is roughly identical to the adjustment of industrial structure and the direction of the optimal allocation of land use structure of Qianwei County, and coincides well with exerting the principal function of land use comprehensive functional areas of qianwei County.Ecosystem service value increases, and the space changes obviously. In period of study time, T he ecological service value of the land use has increased in Qianwei County, and the forest and area also has increased, which become the main reason for the increasing trend of the ecosystem ser vices value. In space Qianwei ecosystem services value of 3 big functions have different amplitude change in different periods, The ecological industry development area which located in the southwe st is the fastest one. This region become more apparent in the green ecological defense in this count y, which is related closely with the main function of the usage of land to safeguard the ecology secu rity.Ecosystem service value of land use/cover change significantly in response. Woodland ecosystems is the most important factor in Qianwei ecosystem service value. On the value of ecosystem services, the contribution rate of farmland are negative in every period, the later period decreased by about 10 percent from the previous period, forest ecosystem service value of the contribution rate in each period are positive.changes of forest land and the forest ecosystem services value of Qianwei are consistent, and changes in the value of ecosystem services is the most important contribution factor. Improve land the saving and intensive utilization levels at the urban industrial development zone, strengthen the construction of basic farmland at the agricultural industry development zone, stable the status of agricultural production, and consolidate the status of the ecological functions of forest service, bring the ecological industry development area into full play, which is the main directions for Qianwei County to make effective and sustainable use of land. |
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