Effects Of Landscape Pattern On Ecosystem Services In The Upper Reaches Of Ganjiang River Basin

In this study,ten landscape pattern indexes and four ecosystem services in the upper reaches of the Ganjiang River basin,a typical mountain region in southern China,were spatially quantified by using remote sensing,climate,soil and hydrology data.Based on the understanding of the correlation characteristics of landscape pattern and ecosystem services,the relative importance,marginal effect and spatial non-stationarity of the impact of landscape pattern on ecosystem services were explored,which could provide reference for adjusting the landscape pattern of land use in the basin according to local conditions and improving the supply of ecosystem services.The main conclusions of the study are as follows:(1)The spatial distribution of different land use types in the upper reaches of Ganjiang River basin is obviously different,with woodland and cultivated land widely distributed.The gardens are mostly distributed in areas with higher elevations.The construction land is mainly distributed in the river banks and flat gully areas.The average patch area,aggregation degree,maximum patch index,edge density and integration degree of forest land were the largest,but the separation degree was the smallest.The patch density of cultivated land is the highest.The average patch area,maximum patch index,patch density,edge density,degree of aggregation and degree of association were all the smallest in the unutilized area.(2)The coefficient of variation of food production service,soil conservation service,carbon sequestration service and ecosystem service index was large,indicating that the spatial difference of ecosystem service was large in the subwatershed.The ecosystem service capability provided by different land use types was different,and the average value of the ecosystem service index of cultivated land was the highest.The overall ecosystem service index showed a lower distribution pattern in the middle and a higher distribution pattern in the periphery,which was the comprehensive spatial performance of the other four kinds of services.The overall performance of ecosystem service index grade area in the basin is "three more and two less",that is,the area of good,medium and poor grade is more,and the area of good and poor grade is less.(3)Ecosystem service index was positively correlated with average patch area,cohesive degree and spread degree,positively correlated with maximum patch index,negatively correlated with patch density and Shannon evenness index,and negatively correlated with separation degree and Shannon diversity index.The basin landscape pattern index and ecosystem service index showed significant spatial positive correlation globally.There are some overlaps of cold and hot spots between landscape pattern and ecosystem service.(4)There is a nonlinear relationship between landscape pattern and ecosystem services.For the ecosystem service index,Shannon diversity index,average patch area and edge density had the greatest influence on the ecosystem service index.With the increase of Shannon diversity index,average patch area and edge density,the ecosystem service index showed nonlinear change,nonlinear increase and nonlinear increase,respectively.(5)There were spatial differences in the effects of landscape patterns on ecosystem services.For ecosystem service index,patch density,edge density and Shannon diversity index had both positive and negative effects on ecosystem service index.The four dominant landscape pattern index regions of the ecosystem service index were positive influence area of edge density,negative influence area of patch density,positive influence area of patch density and negative influence area of Shannon diversity index.