Construction Of Ecological Security Pattern Of The Key Biodiversity Conservation Project Area Of Wuling Mountains Based On Habitat Quality

Human activities continue to drive economic development and changes in land structure,which seriously hinders the protection of biological habitats and landscape connectivity.Mountainous areas are hotspots of biological habitat and biodiversity,however,the urbanization process is also accelerating,a large amount of land with ecological functions is encroached upon subsequently,which profoundly affects the landscape pattern and function of ecosystems,which is not conducive to regional sustainable development.In order to better protect biodiversity and maintain ecosystem stability,building an ecological network can effectively avoid habitat destruction and fragmentation.This is of great significance for rational planning of ecological security,ecosystem protection and restoration,and optimal regulation.This paper takes the Key Biodiversity Conservation Project Area of Wuling Mountains of Guizhou Province as an example,analyzes the dynamic characteristics of land use/cover and landscape pattern from 1990 to 2018,evaluates habitat quality based on the Integrated Valuation of Ecosystem Services and Trade-offs(In VEST)model,and uses the topographic position index to reveal the topographic gradient distribution characteristics of habitat quality.The ecological source was extracted from the results of the 2018 habitat quality assessment,and the landscape connectivity evaluation was carried out by Conefor to determine the ecological source.Based on spatial principal component analysis,the resistance factors were evaluated and the comprehensive resistance surface was constructed.Finally,the minimum resistance model(MCR)is used to identify the ecological corridor and construct the ecological security pattern of the study area.The results of the study showed that:(1)During 1990-2018,the land use types in the study area were mainly cultivated land,grassland and forestland,the main changes were that forest land and grassland decreased by134.4km~2and 241km~2respectively,the area of construction land continued to expand,increasing by 214km~2,and the area of cultivated land and water body increased slightly,increasing by 77km~2and 84.7km~2respectively.The land area of unused land is relatively stable.From 1990 to 2018,cultivated land was mainly converted into forestland and construction land,mainly concentrated in the northeast area of the study area,grassland was mainly transferred to cultivated land and forestland,mainly distributed in the central area of the study area,and forest land was mainly transferred to cultivated land and grassland,distributed throughout the study area.From the perspective of landscape pattern index,the degree of landscape fragmentation in the study area increased,the influence of the largest patch on the landscape pattern gradually decreased,the landscape showed a trend of gradual irregularity and diversification,the number of patches in the landscape increased,and the aggregation and connectivity of patches decreased.(2)The In VEST-HQ model was used to evaluate the habitat quality,and the habitat quality was divided into four grades:low grade,medium grade,higher grade and high grade.During 1990-2018,the habitat quality index was high,and the average habitat quality in 1990,2000,2010 and 2018 was 0.812,0.807,0.809 and 0.805,respectively,showing an overall decrease.The grade of habitat quality is mainly medium and high,and the spatial pattern generally shows a trend of"high east-west,low north-south";The topographic gradient had a significant effect on spatial patterns of habitat quality.High habitat quality distribution became dominant with the rise of topographic gradient,while the low habitat quality distribution was dominant along the low topographic gradient.the low-level gradient.(3)Based on the spatial principal component analysis,the comprehensive resistance surface of the study area was determined,and the ecological resistance of the principal component analysis study area mainly included three types of impact factors:natural habitat impact factor,human activity impact factor,and topographic impact factor.Using the MCR to construct the ecological security pattern,the total area of the 14 ecological source areas identified in this paper is 4871.5km~2,accounting for 14.56%of the study area,which are mainly distributed in the southern,western and eastern parts of the study area,and there are fewer ecological sources in the central and northern regions;The ecologically security zone consists of low-resistance zones,medium-resistance zones and high-resistance zones.The area of low resistance zone is 14763.56km~2,the area of medium resistance area is14007.82km~2,and the area of high resistance area is 4637.34km~2.The minimum cumulative resistance model was used to obtain 38 ecological corridors with a total length of 2935.65km.Based on the above research results,put forward suggestions for optimizing the ecological security pattern,in order to provide reference for the protection and restoration of land space in plateau mountainous areas,ensure regional ecological security,and build an ecological security pattern.