Study On Landscape Pattern And Habitat Quality In Xiangjiang River Basin

Human activities have led to rapid changes in the landscape pattern,affecting the pattern and function of regional ecosystems.The ecological environment of the Xiangjiang River Basin is related to the quality of life and the sustainable development of production in the whole region.The research on landscape pattern and habitat quality of this basin is of great significance to the construction of regional ecological environment and the scientific and rational use of land.Based on the three-phase land use/cover data in 2000,2010 and2018,this study uses Arc GIS and Fragstats software to explore the landscape structure and spatial and temporal evolution of landscape pattern in the Xiangjiang River Basin by using landscape type dynamics,transition matrix,landscape index method and moving window method.The In VEST model is used to evaluate the temporal and spatial change characteristics of the ecological environment from the habitat quality index and the degree of habitat degradation,and Geo DA software is introduced to conduct a bivariate spatial autocorrelation analysis of the two,to explore the impact mechanism of human activities on the ecological environment change,and to propose optimization suggestions.The following research conclusions are obtained:(1)The forest land and cultivated land in the Xiangjiang River Basin are the dominant landscapes.The overall landscape structure remains stable,and some areas are affected by rapid urbanization,construction land receives forest land and cultivated land landscape transfer,the growth is significant;affected by the ecological policies of returning farmland to forest and returning farmland to lakes,the area of arable land has decreased,and the area of woodland and wetland has increased.(2)Landscape pattern analysis with 100 m grain size and 1000 m range shows that the fragmentation and diversity of landscapes increase,and the landscape shape tends to be complex;the patches of construction land change drastically,which strengthens the control over the overall landscape,and cultivated land,grassland and forest land are returned to farmland.The impact of forest and cultivated land occupation-compensation balance policy changes frequently and tends to be fragmented.In the distribution areas of Nanling,Luoxiao and Mulian Jiushan,there are few human activities,and the landscape is agglomerated and the shape is regular and connected.(3)The overall habitat quality of the watershed is relatively good,with high-level habitats and mild degradation as the main ones.The average value of the habitat quality index is decreasing year by year,and the degradation index is increasing year by year,indicating that the ecological environment of the river basin tends to deteriorate;The large area of forestland maintains a relatively complete ecological space,and belongs to the high habitat and mildly degraded distribution area;the central Loushaoheng Yongqiugang water-saving agricultural area is concentrated and contiguous,which belongs to the general habitat and general degradation distribution area;the northern Changzhutan city The core area of the cluster is affected by multiple threat factors such as towns,industrial and mining land,and road networks,and presents a low-level habitat and is highly degraded.(4)Habitat quality was positively correlated with the largest patch index,negatively correlated with the number of patches,patch density,landscape shape index,Shannon diversity index and Shannon evenness index,but not significantly correlated with the spread index.The high-value area is dominated by the upper mountain forest area,and the landscape pattern with patch aggregation and regular shape is conducive to maintaining biodiversity;the low-value area is dominated by the agricultural area in the middle reaches of the watershed and the downstream urban area,with fragmented patches and discrete and complex landscapes.Pattern characteristics are not conducive to maintaining habitat stability.Finally,land use and management suggestions are put forward by division and river section.