| In recent years,human beings have gradually increased their efforts to develop natural resources,and a series of environmental problems have emerged,such as a decline in ecological quality,a decline in biodiversity,and aggravation of ecological environment pollution.The contradiction between the rapidly developing social economy and the fragile ecological environment is deepening,posing a threat to regional ecological security and seriously affecting the construction of ecological civilization and the coordinated development of the region..Under the background of ecological civilization construction,study the landscape ecological effect of land cover and evaluate the regional ecological security level,analyze the impact of regional land development and utilization on the ecological environment,and then identify and select core protection areas,important paths and As a strategic node,building and optimizing a regional ecological safety network is of great significance to improving regional environmental quality and ecological protection.This paper takes Ganquan County,Shaanxi Province,which is located in the loess hilly and gully area,as the research area,selects the land use data of 2010,2015,and 2020,and uses the land dynamic model,comprehensive land use index,and landscape index method to analyze the land use and land use in Ganquan County.Landscape pattern change characteristics;through the landscape ecological security evaluation model,explore the landscape ecological security change characteristics and temporal and spatial evolution laws in Ganquan County,and use the spatial autocorrelation model to analyze the spatial correlation of ecological security in Ganquan County;on this basis,through the ecosystem services The value calculation and the minimum cumulative resistance model construct the ecological safety network of Ganquan County in 2020 and propose optimization strategies.The main conclusions of the study are as follows:(1)From 2010 to 2020,the forest land and cultivated land accounted for the largest proportion in Ganquan County,and the difference in the dynamic degree of other land use was the most obvious,reaching 27.59%;the comprehensive land use dynamic degree was only 0.48%,and the changes in the area of land use types in Ganquan County were relatively stable;The comprehensive land use index increased from 212.51%in 2010 to 213.84%in 2015,and then dropped to 212.90%in 2020;in terms of land conversion types,cultivated land is the main type of transfer out of Ganquan County,and forest land is the main type of transfer in.During the study period,the patch dispersion degree in Ganquan County showed an increasing trend,the complexity of the landscape shape increased,the number of patches increased and the average area decreased,the degree of landscape connectivity was declining,the landscape heterogeneity was enhanced significantly,and the distribution of landscape types was relatively balanced,with a slight downward trend.(2)From 2010 to 2020,the ecological security level of Ganquan County in the southwest was higher than that in the central and northern parts,showing the characteristics of spreading around the county as a whole;in terms of area change,from 2010 to 2020,Ganquan County had high ecological security and relatively low ecological security.The area of high ecological areas increased by 51.47km~2 and 107.66km~2 respectively,and the proportion increased from 14.63%and 20.04%to 16.90%and 24.78%.The proportion of medium ecological security increased from 24.29%to 26.06%,and the proportion of low and low ecological security areas increased from 24.29%to 26.06%.From 23.54%and 17.49%to 18.90%and 13.37%respectively,the ecological security level of Ganquan County is in a benign development trend;in the spatial autocorrelation analysis,the global autocorrelation indices are 0.6062,0.6115 and 0.5535,respectively,indicating that the ecological security of Ganquan County has a high level of development.There is a significant positive spatial correlation.The results of local autocorrelation analysis show that the spatial distribution of ecological security in Ganquan County is dominated by two agglomeration types of "high-high" and "low-low",and other agglomeration areas account for a lower proportion.(3)The ecological source land of Ganquan County is extracted from three levels of ecological security level,ecological service value assessment and ecological protection area.The ecological source land area is about 441.66 km~2,accounting for 19.43%of the total area;a total of ecological attributes and interference are selected 7 resistance factors;determine the weights and construct the comprehensive resistance surface of Ganquan County;on this basis,the MCR model is used to extract 21 ecological corridors in Ganquan County,and 93 ecological nodes are extracted with the help of hydrological analysis tools,and the ecological safety network of Ganquan County in 2020 is comprehensively obtained.And put forward optimization strategies:ecological protection areas covered by ecological sources and Luohe will invest more manpower and material resources,delineate the protection red lines of forest areas and water ecological sources,and Shimen Town,Laoshan Township and Xiasi Bay that are not covered by ecological sources.The northern part of the town should be developed and constructed according to local conditions;the construction of ecological corridors is linked to urban planning.It is suitable to increase forests,grasslands and water areas in the northern part of Xiasiwan Town and the southern part of Dao Town.Expand and enrich ecological corridors and ecological nodes. |
