Optimization Of Land Use Ecological Security Pattern In Yan’an District Delta Under Ecological Pressure

With the accelerated urbanisation process,the regional urban space has been expanding,and the originally continuous ecological space has been damaged and fragmented to a high degree,making the ecological space suffer from increasing ecological pressure and thus affecting the normal operation of the social and economic system.Building a land ecological security pattern is an effective way to cope with the problem of regional ecological pressure,which can guarantee regional ecological security and promote regional sustainable development;a good land ecological security pattern not only helps to improve the imbalance between the supply and demand of ecological space,but also helps to promote the integrity of natural ecological structure and function.This paper evaluates regional land ecological security based on the DPSIR-TOPSIS model,calculates the comprehensive land ecological security score,and identifies different levels of ecological pressure hot pots using nighttime lighting data.The preliminary identification of ecological source sites is based on the Morphological Spatial Pattern Analysis(MSPA)method,and the final ecological source sites are determined based on the patch area and landscape connectivity index;the comprehensive resistance surface is constructed based on consideration of the natural environment and socioeconomic factors in Yan’an,but in order to improve the accuracy and rationality of the potential ecological corridor simulation,it is modified using nighttime lighting data to obtain The final resistance surface of Yan’an City was constructed based on the MCR model;potential ecological corridors and ecological pressure demand corridors of different levels were constructed based on the MCR model,and important ecological corridors were selected using the gravity model;finally,the ecological security pattern of land in Yan’an City was constructed and optimized countermeasures were proposed.The research results show that:1)From 2011 to 2020,all districts and counties in Yan’an had an overall land ecological safety score below 0.8,with some increases and small decreases over the decade,but a steady upward trend overall.2011 saw all districts and counties with an overall score below 0.4,all in the insecure and less secure category,indicating that land ecological safety needs to be taken seriously.However,along with the gradual promotion of ecological protection construction,the ecological security of land in most districts and counties has improved,but there are still six districts and counties in the less secure category.Therefore,the overall ecological safety of land in Yan’an is not optimistic and there is still a long way to go in the future.2)Based on the MSPA,the total area of the ecological core area was identified as 778,545.63 hectares,accounting for 21.02% of the total area of the city,and taking into account the area of the patches and connectivity,the final ecological source land area of Yan’an was determined to be 421,437.96 hectares,accounting for 11.38% of the total area of the city and concentrated in the southern part of Yan’an;however,the unbalanced distribution of the existing ecological source land is likely to cause regional However,the unbalanced distribution of the existing ecological source lands is likely to cause the fragility of the regional ecosystem and make it difficult to meet the demand for land in the whole area of Yan’an.Therefore,the addition of 60,153.35 hectares of ecological source lands in the northern part of Yan’an effectively improves the coverage of ecological source lands,enhances the landscape connectivity between the northern and southern parts of Yan’an,and alleviates the unbalanced demand for ecological supply in the north.3)The combined resistance values of Yan’an City ranged between 1.1257 and 4.7243,with the high resistance areas located in the northern part of Yan’an City,but the aggregation phenomenon was not obvious.In order to improve the accuracy and rationality of the potential ecological corridor simulation,the final resistance surface of Yan’an was corrected using nighttime light data,with resistance values ranging between 0.0428 and 1434.56.The high resistance areas are located in the northern part of Yan’an,and the aggregation phenomenon is obvious,as there are mostly construction land and unused land in this area,and the elevation and slope are low,which is suitable for human production and living.The low resistance area is mainly located in the south of Yan’an City,with a large area of nature reserves,high vegetation cover and low human activities.4)The ecological corridor network in Yan’an includes important ecological corridors and ecological pressure demand corridors of different levels.There are 38 important ecological corridors,which effectively connect the ecosystems in the north and south of Yan’an and are important for the connectivity of the regional landscape;there are 29 ecological pressure demand corridors of different levels,whose ecological functions are different from those of the important ecological corridors,and whose main function is to extend and expand the service range of the existing ecological source areas and enhance the connection between the ecological core areas and the town space.Through the analysis of different types of ecological corridor landscapes,it was determined that the construction of woodland-based ecological corridor landscapes should be based on the original existing woodland,planting vegetation adapted to the local ecological environment and continuously enriching the vegetation types of woodland ecological corridors;the construction of arable land-based ecological corridor landscapes should be based on the adequate protection of the quantity and quality of arable land,and appropriate measures such as returning farmland to forest and grass to maintain the The stability of the regional ecological environment.5)Based on the minimum cumulative resistance value,the ecological function zones in Yan’an are divided into ecological conservation zones,ecological control zones,ecological transition zones and ecological occupiable zones.The ecological conservation zone,which accounts for 45.02% of the total,is the basis of the ecological security pattern in Yan’an and should be protected.The ecological control zone accounts for about 22.78% of the total,which on the one hand maintains the basic stability of the ecosystem,on the other hand alleviates the contradiction between ecological protection and arable land protection,and effectively protects the ecological conservation zone.The ecological transition zone accounts for about 12.25% of the total area.In this zone,the construction of green isolation zones should be improved,so that agricultural production and urban construction are within reasonable limits,effectively alleviating the contradictions between these three areas.The ecological occupiable zone accounts for about 19.94% of the area,where primary,secondary and tertiary industries are mainly developed to provide a material basis for the sustainable development of the ecological security of the region.