Spatiotemporal Changes in Ecological Risks of Land Use in the Tuojiang River Basin Based on Landscape Structure
In this paper,Tuojiang River Basin was selected as the study object,based on the remote sensing data from 2005 to 2020,from the perspective of landscape structure,GIS,GeoDa software and land stochastic matrix were used to build a landscape land ecological risk assessment model,and to analyze the temporal and spatial changes of land ecological risk.The results showed that:1)Cultivated land was the landscape background value of the study area.Affected by natural and human factors,the areas of cultivated land and forest land were decreased over the past 15 years,while the areas of construction land,water body,grassland,and unused land were increased.The area of newly added construction land was the largest,with 91.95%coming from cultivated land(main source of construction land).2)Ecological risk indexes from 2005 to 2020 were calculated,and the Moran's I were all positive.At a 99%confidence level,the significance test was passed,indicating that ecological risk area had a significant positive correlation in space and exhibited a spatial aggregation state.The high-high aggregation was the main aggregation mode of land ecological risk.3)Over the past 15 years,in term of spatial distribution,the low-risk level showed an overall trend of transferring to the middle and lower reaches.The study area was mainly composed of high-risk and higher-risk areas,which were concentrated in the mountainous areas in the upper reaches of the basin and the hilly areas in the middle and lower reaches,and accounting for 49.20%and 48.98%of the total area of the study area,respectively.From the trend of area change,the areas of low-risk areas,lower-risk areas,and medium-risk areas were increased by 1 122.91,3 581.10,and 21 698.83 hm2 respectively year by year.The areas of higher-risk area first increased and then decreased,with an overall increase of 582 436.94 hm2.The areas of high-risk area first decreased and then increased,with an overall decrease of 608 839.78 hm2.The overall ecological risk of land use in the Tuojiang River Basin tended to weaken.Overall,except for a small amount of transformation from higher-risk areas to high-risk areas,most of the other areas were transferred from higher-level risk area to lower-level risk area.The transformation of risk area was manifested as mutual transformation between adjacent levels,indicating that the ecological risk changes of land use in the Tuojiang River Basin were relatively stable and no areas with sharp changes.
Tuojiang River BasinLandscape structureLand ecological risksGeographic information system
万方数据
维普
