| In recent years,the overall situation of the ecological environment of lakes(reservoirs)in China has been deteriorating.Coupled with the weak supervision and management capabilities of the lakes,some lakes have faced the dual threats of pollution and ecological degradation.Jilin Province is located in the hinterland of the Songnen Plain.It is one of the provinces(regions)with rich lake resources in China.In the past 20 years,with the population growth and economic development in the lake basin,excessive development and human activities have changed the status of land use in the basin,and the impact of global climate change has caused changes in lakes(reservoirs)in Jilin Province,and some lake ecosystems Degradation,fragmentation of habitats,reduction of biodiversity,and degradation of ecosystem services.The amount and area of lake water storage decreased,lake sedimentation occurred,and lake water eutrophication occurred.The author studies the spatial and temporal characteristics of the lakes in Jilin Province in the past 20 years and changes in the landscape pattern characteristic index,and reveals the driving mechanism of lake evolution.It is of great significance for Jilin Province to formulate and implement countermeasures for lake environmental protection and protection,and to study and establish a long-term mechanism for lake ecological environment protection.Under the support of the scientific research project of the Jilin provincial Environmental Protection Department of Jilin Province,the research project"Jilin lake environmental status assessment and the comprehensive technical system of ecological environment protection",this research is based on remote sensing satellite images to obtain the lake(reservoirs)distribution map of Jilin Province in the past1995-2015 years and 20 years,and should use the spatial analysis technique of GIS to reveal the lake The characteristics of space-time distribution,the landscape pattern characteristic index of the lake(reservoirs)distribution are analyzed by the landscape ecology principle,and the main process of the landscape pattern change is revealed.By screening natural and human driving factors,the driving factors of the lake(reservoirs)environment change in our province(water,temperature,GDP,population quantity,etc.)are established.To make clear the main driving force of the change of the lake reservoir environment.The main conclusions of this paper are as follows:(1)From 1995 to 2010,the shrinking area of lakes(reservoirs)in Jilin Province is also decreasing.After 2010,the shrinkage of the water surface area of the lake reservoir has eased and the area has gradually increased.Among them,the area of lakes in the west of Jilin Province shrank by 15.81%,the central area shrank by27.67%,and the eastern area shrank by 19.04%.The annual average number of lakes was 148 in the west,69 in the center,and 26 in the east.The number of lakes in the west is greater than that in the middle,much larger than in the east and the area of lakes in the west is less than that in the central and eastern regions.(2)Based on Fragstats 4.2,the landscape pattern index of the lake(reservoirs)in the east,middle and west of Jilin Province was calculated.Average annual plaque area(PD):Eastern>Central>Western;Largest patch index(LPI)values:Western>Eastern>Middle,indicating that western lake landscapes are affected by human activities more than the eastern and central regions;landscape shape index(LSI)values:Western>Central>Eastern,indicating that the western landscape has a low degree of regularization and complex edges,and is more susceptible to human activities.From1995 to 2010,the COHESION was in a downward trend,and the index value increased from 2010 to 2015.The"Connecting"project effectively changed the connectivity of the western lake landscape.(3)This paper selects seven key lakes(reservoirs)in Jilin Province for detailed analysis and concludes that the water area of Chagan Lake has been well protected in the past 20 years,and the lake area has not changed significantly.The average area value is 310.1 km~2;the moon bubble is nearly 20 years The area affected by the Nen River has changed greatly;the water area of the Boluo bubble in 2003 was five times that of the 2001;the Xinlicheng Reservoir,the Shitoukoumen Reservoir,and the Erlongshan Reservoir were in a state of shrinkage from 1995 to 2010,and the water area in 2010-2015 was It was restored;Songhua Lake had a maximum water area of335.2 km~2 in 2005,and the smallest water area in 2015 was 184.53 km~2,with an average lake area of 289.92 km~2.(4)This paper analyzes the impact of natural driving factors and human-driven factors in Jilin Province on the area and number of lake banks,and concludes that the increase in population is caused by Grade I(1-10 km~2),Grade II(10-50 km~2)and Grade IV(>100 km~2).The main reason for the shrinkage of the lake depot area and the decrease in the number of the lake depots is that,at the same time,the regional GDP has increased the area of the lake bank of Grade II(10-50 km~2)to a certain extent;the water area of Erlongshan Reservoir and Songhua Lake has shrunk,and the population has also contributed to the shrinking of the water area of Chagan Lake. |
