Analysis On Landscape Change And Ecological Stress Of Sha River Watershed In Yong’an

The dissertation, based on the theories of landscape ecology and with Sha River Watershed in Yong’an as the research object, interprets Landsat TM remote sensing images in1991and2010with RS and GIS to obtain the distribution map of landscape types in the research area; And then it works out indexes of23landscape patterns of the research area with Fragstats software. Landscape indexes are screened according to correlation analysis and factor analysis, then quantitative analysis is made about changes of landscape patterns of the research area; The change area of landscape types, rate of change and detailed transformation types are analyzed through the transfer matrix of landscape types; accordingly, features of ecological stress to the river’s ecosystem are analyzed from perspectives of landscape structure and functions; finally, exploratory ways of ecological restoration of the research area are offered in the dissertation.The main conclusions are as follows:(1) The three common factors, which were respectively the factor of area and extent characteristics, the factor of shape characteristics and the factor of spatial distribution characteristics, could explain main information of23landscape indexes.(2)Through a detailed analysis of features of Landscape Pattern, we can find that the woodland is the dominant landscape in target area, the division structure is the most reasonable; cultivated land is getting less and division is centralized. The land for construction has increased with the rapidest rate, the level of aggregation and connectivity are both growing up. The main conversion is that woodland, cultivated land and garden land convert into the land for construction.(3)The ecological threats in target area is caused by the changes of landscape pattern under the influence of human activity, such as the reduction of the woodland, the increasing of the land for instruction, the centralized division of land for instruction, and the over exploitation of slope land. The approach of ecological restoration of optimization distribution of landscape and the management of riparian zone and slope farmland has been brought forward.