| In the context of global change,due to the increasing frequency of human activities,the change of landscape pattern has intensified,making the originally fragile ecological environment face more severe ecological security problems.This poses a certain threat to the health of regional landscape patterns and ecosystems,as well as to the sustainable development of human beings.Based on the characteristics of regional land use change,objectively evaluating the temporal and spatial characteristics of landscape ecological risks can provide important decision support for the rational allocation of regional land resources and optimization of landscape patterns and scientific basis for ecological security construction in the region.In view of this,taking the Qinling-Daba Mountains as the research object,and based on the surface cover data in 2000,2010 and 2020,this paper used the Ca-Markov model to predict the spatial distribution pattern of land use under the two scenarios in 2030,and analyzed the temporal and spatial evolution law of land use in Qinling-Daba Mountains from 2000 to 2030.Then,based on the land use data of Qinling-Daba Mountains from 2000 to 2030,and by constructing a landscape ecological risk evaluation model,the spatio-temporal differentiation characteristics and spatial correlation of the ecological risk of the Qinling-Daba Mountains from 2000 to 2030 were explored,Finally,the influence factors were analyzed by geographic detectors,and reasonable suggestions were put forward in combination with ecological function zoning.The main conclusions were as follows:(1)Based on the prepared land use suitability atlas,the CA-Markov model was used to predict the spatial distribution pattern of land use in the Qinling-Daba Mountains in 2020.The simulation results were tested from the perspective of quantity and space,and it was found that there was little difference in the number of land use types,and the Kappa coefficient was as high as 0.8973,indicating that the simulation results were relatively reliable and can be used to simulate and predict the spatial distribution pattern of land use in the Qinling-Daba Mountains in 2030.(2)From 2000 to 2020 and in the two development scenarios of 2030,forest land,cultivated land and grassland are always the main land use types in Qinling-Daba Mountains.From 2000 to 2020,the area of forest land increased significantly,followed by the area of construction land and water area,while the area of grassland and cultivated land decreased to varying degrees.The conversion between grassland,forest land and cultivated land was the most active and gradually frequent,and the conversion between other land use types was relatively stable.The transformation part was manifested in space: local concentration,overall dispersion,and the spatial scope was gradually expanded,and the spatial distribution was more dense.Under the two development scenarios in the future,the land use types of Qinling-Daba Mountains were significantly different.However,the transformation between various land use types was significantly weakened,and the area of spatial pattern change was also reduced.Under the natural development scenario,the area of forest land decreased sharply,and the area of cultivated land,grassland,and construction land increased to varying degrees.Under the sustainable development scenario,the expansion of construction land area only came from cultivated land,the grassland area changed from decrease to increase,and other land use types increased to varying degrees according to the original trend.(3)From 2000 to 2020 and in the two development scenarios of 2030,the overall ecological risk of Qinling-Daba Mountains landscape was relatively low,and the spatial differences were significant.The ecological risk level of the landscape as a whole showed a spatial distribution pattern of high on the east and west sides and the middle high,and the north and south were low,which was partially manifested as the distribution characteristics of the circular radial around the center high,which was closely related to the topographic environment in the region.In terms of spatial distribution,there was a significant positive correlation between the landscape ecological risk value,and the spatial agglomeration effect was obvious,and the overall low-low and high-high aggregation were the main characteristics,showing the distribution characteristics of east-west high and north-south low,which was highly consistent with the spatial distribution pattern of landscape ecological risk in the same period.(4)From 2000 to 2020,the ecological risk of Qinling-Daba Mountains landscape continued to decline,the low-value ecological risk area continued to expand,and the high-value ecological risk area shrunk significantly,indicating that the quality of the ecological environment in the study area was gradually improved,and the ecosystem became more and more stable.From the perspective of the spatial distribution pattern changes,most of the ecological risk areas were in a stable state,and the improvement area is distributed in the southeast and northwest of the study area,and the deterioration area was scattered in the central,eastern and western marginal areas of the study area.In 2030,most of the landscape ecological risks would still be in a stable state with obvious local changes.Under the natural development scenario,affected by the frequent conversion between land use types,the area of the low ecological risk area increased significantly,and the area of the low and medium ecological risk area decreased sharply,and the improvement area spread throughout the study area.Under the sustainable development scenario,affected by restrictive conditions,the area of high ecological risk was significantly reduced,which was obvious in the western part of the study area and the Danjiangkou area.The area of low ecological risk was significantly reduced,and the area of medium ecological risk increased,which was concentrated in the northwest and northeast of the study area.Finally,according to the results of landscape ecological risk assessment and combined with the service functions of ecological functional areas,corresponding management suggestions were put forward.In order to provide scientific basis and scientific basis for realizing the rational allocation of land resources in QinlingDaba Mountains,continuously improving the quality of ecological environment and promoting regional sustainable development.theoretical support. |
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