| Mountains are sensitive areas for global change and play an important role in ecological security.With global warming,the combined effects of climate change and human activities make mountain ecosystems very fragile,and the supply capacity of mountain ecosystems is seriously threatened.Mountainous areas account for about a quarter of the world’s total land area,provide direct or indirect habitation for about 52% of the world’s population,and are an important part of global biodiversity and cultural diversity.Mountain ecosystem services can provide a wide range of benefits for human well-being,including provision,regulation,support and cultural services.Therefore,the changes of mountain ecosystem services and the carrying capacity of the ecological environment have always been the research hotspots of geography and ecology.In this study,the Qinling-Daba Mountains,the main body of the north-south transition zone in China,were selected as the study area.Fragstats software,PLUS model,In VEST model and SPSS software were used to analyze the changes in the landscape pattern of the Qinling-Daba Mountains from 2000 to 2035.Scenarios and ecological protection scenarios,simulate the characteristics of land use change under different future scenarios,evaluate the current and future ecosystem carbon storage in QinlingDaba Mountains,and comprehensively analyze the factors affecting the temporal and spatial evolution of Qinling-Daba Mountains ecosystem carbon storage.The main research conclusions are as follows:(1)The main land use types in the Qinling-Daba Mountains are forest land,grassland and cultivated land.The forest land is mainly distributed in the southwest,central and eastern regions of the Qinling-Daba Mountains,the grassland is mainly distributed in the southwest,and the cultivated land is mainly distributed in the northwest and northeast regions.From the perspective of land use dynamic degree,the single land use dynamic degree in Qinling-Daba Mountains shows a trend of "increase and then decrease",and the comprehensive land use dynamic degree shows a trend of "first increase and then decrease";The land use change in Bashan Mountains shows the characteristics of continuous increase of construction land and grassland,and a sharp decrease of cultivated land;from the comprehensive index of land use degree,the comprehensive index of land use degree in Qinling-Daba Mountains shows a trend of first decreasing and then increasing.From the patch level,the land use types with the highest landscape fragmentation and landscape diversity in Qinling-Daba Mountains are cultivated land,forest land and grassland,and the overall landscape shape changes from regular to irregular;The landscape fragmentation index showed a trend of first decreasing and then increasing,the landscape clustering and dispersing index showed a fluctuating trend,and the landscape shape index showed a continuously increasing trend.(2)Under the natural growth scenario in 2035,the land use change in Qinling-Daba Mountains shows a continuous decrease in the area of arable land and grassland,and an increase in the area of forest land,water area and construction land;from 2015 to 2035,the landscape of land use types in Qinling-Daba Mountains under this scenario Fragmentation increases,landscape diversity gradually decreases,and the number of patches in the landscape tends to be complex.Under the 2035 arable land protection scenario,due to strict restrictions on the outflow of arable land,the area of arable land,forest land and water area will increase;from 2015 to 2035,the Qinling-Daba Mountains landscape will be more fragmented,and the landscape diversity will decrease,and the landscape will be spotty.The number of blocks tends to be complex.Under the ecological protection scenario in 2035,ecological land such as forest land,grassland and water area in Qinba Mountains is effectively guaranteed.However,the area of construction land increases rapidly,but the increased area under the ecological protection scenario is smaller than that in the natural development scenario;from 2015 to 2035,the Under the scenario,the fragmentation degree of Qinba mountain landscape is greatly reduced,and the landscape diversity is gradually reduced,indicating that the patch types in the landscape are gradually becoming consistent.(3)From 2000 to 2015,the spatial distribution pattern of carbon storage and carbon density in the Qinling-Daba Mountains ecosystem remained basically stable.It can be seen that the areas with higher carbon storage are mainly distributed in the southwest,central and eastern parts of the study area,mainly due to the high vegetation coverage and large forest coverage in these areas;the areas with lower carbon storage are mainly distributed in the study area.The topographically flat areas in the central and northeastern regions are mainly due to rapid economic development,high population density and increased construction land.In2035,the ecosystem carbon storage and carbon density decreased in the natural development scenario,the cultivated land protection scenario and the ecological protection scenario.Among them,the natural growth scenario decreased the most;the carbon storage and carbon density of different landscape types were in descending order.The order is: forest land>grassland>arable land>construction land>water area>unused land;the carbon storage and carbon density in different provinces are in descending order:Shaanxi>Sichuan>Gansu>Hubei>Henan>Chongqing;3 different scenarios in 2035 The overall spatial distribution pattern of ecosystem carbon storage in the study area showed a spatial distribution characteristic of "high in the west and low in the northeast".(4)The analysis results of the influencing factors of the temporal and spatial evolution of ecosystem carbon storage in Qinling-Daba Mountains show that land use/cover and changes in ecosystem carbon storage show significant consistency,and the change in land use quantity determines the quality and spatial distribution pattern of ecosystem carbon storage;With the elevation,the ecosystem carbon storage and carbon density in Qinling-Daba Mountains showed a trend of "first increase and then decreased";the ecosystem carbon storage and carbon density on different slopes in Qinling-Daba Mountains showed a "W"-shaped change trend as a whole;The vegetation coverage in Qinling-Daba Mountains is consistent with the changes in ecosystem carbon storage and carbon density,that is,the higher the vegetation coverage,the higher the ecosystem carbon storage and carbon density content;Reserves and carbon density showed a fluctuating trend of "increase first and then decrease".In addition,the results of correlation analysis show that,from 2000 to 2035,the carbon storage of the Qinling-Daba Mountains ecosystem has a strong and significant positive correlation with vegetation coverage,and it is closely related to slope,precipitation,clay,silt,sand and altitude.There was a significant positive correlation,and a significant negative correlation between population density and economic density. |
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