Landscape Change And Ecological Risk Assessment Of Ecological Resettlement Area

Ecological migration is a kind of special migration behavior or type accompanied by ecological pressure transfer.The direct impact on the immigration area is to change the structure and type of landscape,theoretically,there will be a dominant or recessive ecological risk.Based on the land use/Cover Change(LUCC),the theory of landscape ecology and ecological risk as a guide,taking Hongsipu county as an example,5 Landsat TM images in 1995,2000,2005,2010 and 2015 were selected as the data source,using the integrated technology method of ArcGIS?ENVI?Fragstats and Geoda spatial autocorrelation software to study ecological risk problem of landscape pattern in ecological resettlement area.Research results showed that:(1)The dominant land landscape elements in Hongsipu county was the grassland,accounting for 58%,followed by cultivated land,accounting for the proportion of 32%.The smallest is unused land and waters.Grassland area decreased,other land landscape area showed a continuous increase,especially the cultivated land area increased the most and the construction land was in the second place.The change of landscape area responsed the trend of the construction and development.Cultivated land?unused land and desert were sharply changing during the study.The land categories conversion was fierce in these three landscape and grassland.As the limitation of water area,the conversion activities with other landscape types were the weakest.All types of landscape pattern fluctuated complicated.But overall,landscape was developing towards the trend of fragmentation and heterogeneity.(2)The distribution of landscape ecological risk grade was of certain regulation in Hongsipu County.Hongsipu county covered by high risk area and higher risk area at the beginning of the study period,and dominated by high and medium risk area during the middle and late phase of study period(2005-2015),and high risk area decreased,low risk area increased,the distribution of the ecological risk was in the shape of"spindle" structure.From the perspective of ecological risk distribution,the high and higher risk areas were mainly distributed in the middle north part and southwestern part of Hongsipu county,which roughly corresponded to Hongsipu town,north central of Liuquan and Taiyang Mountain town and Southwest of Dahe town roughly.The low value center of ecological risk was the most evident in the middle part of the central and southern part of Hongsipu county,namely,the middle of the Xinzhuangji town,followed by the eastern boundary of the Taiyangshan town and the Liuquan town.(3)There was a certain accumulation affect in land use ecological risk index in space of Hongsipu county.Moran's I index fluctuated during the study period,Moran' I values were maintained at more than 0.4500 with the exception of the year 2000,which value was 0.3494,Moran's I index in 2015 reached the highest value of 0.5126.The variation of Moran s I index represented the variation of spatial homoplasy in different periods of Hongsipu county.The distribution of local spatial autocorrelation LISA index was dominated by high-high aggregation(H-H)and low-low aggregation types(L-L),and the low-high aggregation(L-H)and high-low aggregation(H-L)types were not obvious.High-high aggregation(H-H)was mainly found in northen and southwestern part of Hongsipu.Low-low aggregation types(L-L)was mainly found in east-central Hongsipu county.While high-low aggregation(H-L)and low-high aggregation(L-H)types scattered around high-high aggregation(H-H)and low-low aggregation(L-L)types.(4)According to the temporal and spatial variation differentiation regularity of ecological risk in Hongsipu County,this study proposed the following recommendation:choosing the scientific location of resettlement area,planning the immigrant population capacity rationally;Changing the structure of agricultural industry,building a modern and efficient water-saving agriculture;Strengthening the protection of ecological environment,improving the irrigation area and small watershed management;Formulating different risk management suiting local risk degree conditions.