The Intensity Of Human Activities In The Middle Reaches Of Heihe River And Its Influence On Wetland Landscape Pattern

As one of the three major ecosystems of the earth,wetlands play an important role in maintaining the balance of ecosystems.However,due to the intensification of human activities,the global wetlands face such problems as degradation or loss.The middle reaches of Heihe River is a hot area of human activities,which makes the area of wetlands in this area decrease continuously,and the ecological environment is seriously disturbed and destroyed.The spatial and temporal distribution of human activity intensity in the middle reaches of Heihe River is analyzed,and the effect of human activity intensity on wetland landscape in the study area is explored,In order to enrich the research case of the influence of human activities on the wetland in the middle reaches of Heihe River,and provide objective and scientific support for the protection,restoration and sustainable development of the wetland landscape in the middle reaches of Heihe River.Based on the theory of land science and landscape ecology,the dynamic process of wetland landscape in the middle reaches of Heihe River is revealed by remote sensing and Arc GIS technology in this paper.The spatial and temporal variation and agglomeration characteristics of human activity intensity in the middle reaches of the Heihe River are explored by the methods of calculation model of human activity intensity,grid analysis,natural discontinuity classification and spatial autocorrelation analysis,etc.Based on the calculation of landscape index,the change of wetland landscape pattern pattern with the change of human activity intensity is revealed from the level of type and the level of landscape.The main findings are as follows:(1)Quantitative Variation Characteristics of Wetland Landscape in the Middle Reaches of Heihe River,The area of natural wetland decreased from 1975 to 2016,and the area decreased by 7462.47hm2.The area of constructed wetland increased gradually,and the area increased by 1249.33hm2.The area of non-wetland type increased gradually,and the area increased by 6312.13hm2.Spatial Variation Characteristics of Wetland Landscape in the Middle Reaches of Heihe River,With the increasing intensity of human activities,the landscape types in the study area changed significantly,including the encroachment of non-wetland landscape on wetland types,the encroachment of constructed wetland on natural wetland and the degradation of natural wetland.(2)In the analysis of the change of the intensity of human activity,the equivalent area of construction land and the intensity of human activity in the whole region of the middle reaches of Heihe River from 1975 to 2016 mainly shows the trend of annual increase.The spatial distribution of human activity intensity is mainly medium intensity,low intensity and low intensity,and shows the characteristics of middle high and low surrounding.In the study period,the intensity of human activities in the middle reaches of Heihe River has the obvious spatial agglomeration characteristics,and the main type is high type and low type.(3)Gradient Response of Human Activity Intensity and Wetland Landscape Pattern,At the landscape level,with the increase of human activity intensity,In general,the diversity of wetland landscape shows a trend of increasing first and then decreasing,and the fragmentation degree increases.At the type level,with the increase of human activity intensity,the shape of natural wetland and constructed wetland tends to be simpler,and the fragmentation of natural wetland and constructed wetland is more serious with the intensification of human activity intensity.