Ecological Safety Evaluation Of Land In Longnan City

Longnan City,as one of the four major development areas of geological hazards in China,has complex topography and geomorphology,staggered distribution of geological fracture zones and fragile land ecological environment.The geological and ecological environment has seriously affected and restricted the development of local economy and environment.Therefore,land ecological security evaluation and early warning is important for understanding and deconstructing the ecological security situation and change trends in Longnan City.In this paper,20 indicator factors are selected based on landuse data,statistical data and disaster point data for a total of eight years in 2000,2003,2006,2009,2012,2015,2018 and 2020,an indicator evaluation system based on the DPSIR model is constructed,while the geographic detector model and mutation model are used from two dimensions of time and space.The analysis of the impact degree of indicators and the study of police situation are carried out.The main research results and conclusions achieved are as follows:(1)Revealed the spatial and temporal variation characteristics of land ecological security in Longnan city.During the study period,based on the DPSIR model of Longnan City land ecological security evaluation index system,the land ecological safety status of the study area shows a trend of gradual improvement and optimization,the proportion of “insecure” grade area in the land ecological security grade decreases from 15.32% in 2000 to 12.13% in 2020,while the area of “secure”grade area increases more,from 6.15% in 2000 to 16.79% in 2020.indicating that more and more areas of Longnan city land ecosystem structure tends to improve and resistance to stress enhance.Spatially,in 2020 compared with 2000,insecure region area shrink,medium security grade area expand,land ecological security spatial pattern security advantage is obvious,the overall pattern of spatial distribution gradually healthy,ecological security index growth,land ecological security continues to be good.(2)Screening out key indicators affecting the ecological safety status of land in Longnan City.Geographical probe on the DPSIR model of different levels and single indicator factors are analyzed,through the divergence and factor detector results obtained,the main impact on the ecological security of Longnan City land level for the driving force layer and the impact layer;single indicator factors have the strongest impact on the per capita GDP,agricultural fertilizer application and forest cover.The interaction detector between different dimensions of the DPSIR model and the influencing indicator factors are found to be mainly in the form of a two-factor enhanced or non-linear enhanced relationship through the interaction probe.The ecological detector probe is used to find that the indicator factors of GDP per capita,afforestation area GDP per capita,afforestation area,forest cover,human disturbance index and land utilization rate have significant influence on the spatial distribution of land ecological security.This can be seen: the current situation of land ecological security in Longnan city mainly exists in the excessive use of agricultural fertilizers,unbalanced water and soil coordination,human interference index,unbalanced total power of agricultural machinery and high density of geological disasters and other land ecological security problems,Some of the problems have had a serious impact on the stability of the overall function of the ecological security of the land in Longnan city.(3)The development status of land ecological security alarm in Longnan City was discussed.Longnan city overall land ecological security warning level mainly in the “good level” and “better level” range.Analysis of the early warning results of land ecological safety at different levels: the early warning results of land ecological safety at the social level are mainly concentrated in the two levels of“good status” and “better status”;the early warning results of land ecological safety at the economic level are all greater than 0.97,which is the first level of “good status”.Indicating that the growth of regional economic income,GDP and economic growth are conducive to the mobilization of more resources to promote social and ecological construction,social equity and harmony,a green and healthy living environment;the early warning results of land ecological safety at the environmental level are located at the first and third levels.“good status” and “early warning” level.Based on the above findings the following recommendations are made: to prevent agricultural surface source pollution caused by excessive use of agricultural chemical fertilizers,the use of organic fertilizers should be encouraged to promote the development of green agriculture.Meanwhile,for the impact of geological disaster density indicators on land ecology,risk prevention and response capability should be strengthened,natural disaster defense lines should be accelerated,weak links in disaster relief should be closed,disaster early warning monitoring and disaster prevention infrastructure should be improved and response capability to natural disasters should be enhanced.Finally,the government should increase propaganda efforts to promote ecological civilization and advocate green development.