| The carbon in the ecosystem is mainly stored in vegetation and soil,and is divided into four parts:aboveground carbon pool,underground carbon pool,dead carbon pool and soil carbon pool.Carbon storage and its changes are important indicators of carbon pool function,which reflect regional climate and ecological conditions,and the research on carbon storage and its changes has important theoretical significance and use value for mining,maintaining and improving the potential of regional ecological spatial carbon sinks and realizing China’s"Carbon peaking and carbon neutrality"goal.Located in the eastern part of Shanghai,at the confluence of the Yangtze and Qiantang rivers,the Pudong New Area is subject to frequent and complex changes in the carbon storage of the ecosystem due to sediment erosion and coastal engineering.As the vanguard of China’s opening up,Pudong New Area has undergone significant changes in carbon storage in recent years due to rapid economic development and rapid improvement of urbanization level,under the influence of various factors of natural environment and human activities.In this dissertation,the land use map of Pudong New Area from 2000 to 2020 is obtained by using the Landsat series of remote sensing images,and the land use change analysis is carried out.On this basis,combined with carbon density data,the carbon storage in Pudong New Area from 2000 to 2020 was obtained by using the InVEST model,its changes were analyzed,and the influence of nine factors in the natural environment and human activities on the change of carbon storage was detected by using geographic probes.The main conclusions are as follows:(1)From 2000 to 2020 year,the land use in Pudong New Area was mainly construction land and cultivated land.Construction land,water and forest land continued to grow,cultivated land,other land and reclamation land continued to decrease,grassland first decreased and then increased,and overall decreased.The comprehensive land use dynamics in 2000-2010 and 2010-2020 were 3.39%and 1.44%,respectively;the land use pattern in 2010-2020 was more stable than that in 2000-2010;in 2000-2010 and 2010-2020,the single most dynamic land use type was forest land and construction land,respectively,the former reached 21.46%,and the latter was 3.17%.From 2000 to 2020,the transfer between land uses in the study area was frequent,and the land use types other than other land use and reclamation land were transferred out and transferred in to different degrees,cultivated land was the largest land use type transferred out,a total of 464.86 km~2was transferred,425.48 km~2was transferred to construction land,and construction land was the largest land use type transferred in,with a transfer area of 523.84 km~2.The land type with the largest transfer area in all land types is construction land.From 2000 to 2020,the trajectory of land use change was mainly stable,with a total area of 674.33 km~2,accounting for 47%of the total regional area,of which stable construction land was the mainstay,with an area of 391.82 km~2,mainly distributed in the central and western regions,and more concentrated in the west.The trajectory of variable land use change is mainly distributed in the western and eastern coasts,and the land use changes in the eastern coastal areas are more frequent and complex than those in the west.(2)The total carbon storage in 2000,2010 and 2020 was 59.53×10~5Mg C,62.84×10~5Mg C and 61.94×10~5Mg C,respectively,showing a trend of first increasing and then decreasing.aboveground carbon storage showing a decreasing trend year by year,and belowground carbon storage and soil carbon storage showing a trend of increasing year by year.Among all types of land use change in the study area from 2000 to 2020,reclamation land,forest land,grassland,water area and other land were positive contribution factors,and the sum of positive contribution rates was 72.39%.Reclamation land was the main positive contribution factor.Construction land and cultivated land were negative contribution factors,and the sum of negative contribution rates was-27.61%.Construction land was the main negative contribution factor.The contribution rate of cultivated land to carbon storage changed from positive to negative,and the contribution rate of reclaimed land,grassland,woodland,water area and other land to carbon storage changed from high to low.(3)From 2000 to 2020,the standard deviation elliptical angleθof carbon storage in the study area decreased from 146.81°to 143.159°,and although the spatial distribution of carbon storage in the study area maintained the pattern of northwest-southeast,there was a trend of transformation to due west-due east.From 2000 to 2020,the center of gravity of the spatial distribution of carbon storage first shifted 1.83 km to the southeast and then0.35 km to the northeast,showing an overall trend of southeastward movement.From the direction of the long axis,the distribution of carbon storage from 2000 to 2020 showed the directionality of northwest-southeast,the elliptical long axis first expanded and then decreased,and the short axis gradually expanded,combined with the elliptical range,carbon storage was dispersed in the northwest-southeast direction and northeast-southwest direction,especially in the northeast and southeast directions,the increase of carbon storage in the eastern part of the study area was more obvious,but the decrease of carbon storage in the west was not obvious.(4)In 2000,2010 and 2020,the Moran’s I of carbon storage in the study area were0.838,0.662 and 0.415,respectively,and the Moran’s I decreased with the increase of years,and the agglomeration effect of the spatial distribution of carbon storage in the study area was constantly weakening.The LISA map of carbon storage from 2000 to 2020 is dominated by high-high agglomeration and low-low agglomeration.In 2000,the spatial distribution of carbon storage showed a pattern of"high in the west-low in the east",and in 2010 and 2020,the spatial distribution of carbon storage showed a pattern of"low west-medium high-low in the east".According to the calculation results of Moran index and the LISA clustering map,the spatial agglomeration characteristics of carbon stocks in the study area from 2000 to 2020 showed a trend of weakening and dispersion.(5)From 2000 to 2020,land use degree was the main influencing factor of carbon storage changes in the study area,followed by soil type,average annual precipitation,and population density(P<0.05)on carbon storage changes was not particularly significant compared with other factors.Except for land use,soil type and average annual precipitation,there were no significant differences between other factors on of carbon stock changes.The influence of single factors on carbon storage changes was significantly enhanced under the interaction of two pairs,and the interaction between land use degree and soil type was the largest,at 0.337,followed by the interaction between land use degree and average annual precipitation,which was 0.330.Pudong New Area had the highest carbon storage growth when the elevation range was 0-7 m,the slope was greater than10.13°,the slope was no slope,the soil type was coastal saline,the average annual temperature was 16.25°C-16.31°C,the average annual precipitation was 1 132.41-1 150.02mm,the land use degree was 200-268.24,the population density was 1.76-3.32 ten thousand people/km~2,and the GDP was 291 799.79-644 331.46 ten thousand yuan/km~2.Strengthening the operation and management of the eastern coastal zone,optimizing land use methods,and protecting soils with strong carbon sequestration capacity will help improve the carbon sink capacity of the Pudong New Area. |
PDF Full Text Request