| With the rapid development of China’s economy and the progress of new urbanization, the rural peopleconstantly immigrate to towns and the urban construction land also expands. The human’s influence on the regional ecological safety has become more obvious, especially unreasonable land use patterns, whichdamage the original ecological landscape and the region’s natural biodiversity,break off regional ecological process, and seriously disrupt the regional ecological stability and regional ecological safety. Objective and quantitative evaluation of ecological risk level on regional landscape, and research on the dynamic changes of land use and spatial and temporal characteristics of ecological risk level on regional landscape with the correlations, which allows for the scientific plans of regional development, optimization of land use structure, and organic coordinated development of regional society, economy, population, resources and environment.This thesis takes Xichang City in Sichuan Province as theresearch area. Based on 2010 and 2014 Xichang City surveying data on land use changes,and by updating and supplementing sources, 2010-2014 land use dynamic characteristics in this area are analyzed.Then, by using the Patch Analyst plug-inof Arcgis10.1, the number, area, and average area of patches, and 13 other landscape indices are selected.Based on landscape level and landscape type, regional landscape structure changes in Xichang City are measured and analyzed. Meanwhile, a regional ecological risk assessment based on landscape pattern indices is built, and ecological risk level on regional landscapeof the research area during the research period are measured and analyzed.Finally, taking 37 countries and towns in Xichang City as the evaluation unit, and through using Arcgis10.1 and ESDA(Exploratory Spatial Data Analysis), spatial and temporal characteristics and Spatial autocorrelationof ecological risk level on regional landscape in 2010-2014 Xichang City are analyzed, and the changes of land use and elastic coupling index to ecological risk level on regional landscape are measured, which could provide some reference for the protection of regional ecological and environmental safety, and optimize land use structure.The main conclusions of this thesis are:(1)The main feature of land use variation in 2010-2014 Xichang City is the increase of construction land and the decrease of agricultural land and ecological land, especially the substantial growth of urban and industrial land and rapid decline of arable land. Forest occupies a dominant position in land use structure, accounting for more than 57% of the city’s total area.The changes in land use structure are showed mainly in the rapid transfer from other types of land, especially cultivated land to the construction land, mostly urban and industrial land. Spatial characteristics of land use focuses on the Xichang City area and the central region of the Anning River in its vicinity, with the highest extent of land use in Gaojian Countryside, and a gradual increasing trend is evident.In contrast, the extent of land use in the western mountainous land is low and has no changes.(2)2010-2014 Xichang City landscape pattern shows increase of landscape fragmentation, landscape patches dispersion, and irregular landscape shape affected by external disturbances. Changes in landscape patterns display that except woodland and grassland landscape,landscape patches fragmentation are larger in other types of landscape, especially in urban and industrial land landscape. Most landscape are influenced strongly by external factors.The fluctuation in ecological risk level on regional landscapeis very low. Ecological risk remains at a high level, in which woodland landscape and farmland occupies a high proportion. Meanwhile,there isan upward trend in risk level in urban, industrial, transportation and other land landscape.(3)Temporal and spatial patterns of ecological risk level on regional landscapein 2010-2014 Xichang Citygenerally exhibit the decline in high ecological risk areas, relatively high ecological risk areas andrelatively low ecological risk area, and rise in medium ecological risk areas and low ecological risk areas.The ecological risk areaswhich have commons in spatial pattern tend to get together, especially high ecological risk areas whichgather in flat and longitudinal valley of Anning River with good natural conditions, which is located in central Xichang, while low ecological risk areaslie annularly in east and west sidesmountains of the Anning River Valley. This shows a spatial positive correlation obviously, and forms anannular situation, with a high center and a low surrounding.There is an elasticcoupling positive correlation in ecological risk level on landscapein 54.05% of country land, which is mainly located in the Anning River Plain and transition districts between east and west mountains, which indicates that dynamic change in land use is an important force behind change in the ecological risk level on regional landscape, and there is a spatial trend thattransferringto the medium and relatively lower level ofregional landscape ecology in topographical transition zone. |
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