Carbon Storages And Carbon Sequestration Potentials Of The Terrestrial Ecosystems On The Loess Plateau

Under the background of global climate change,terrestrial ecosystem plays an important role in carbon sequestration.The Loess Plateau has a fragile ecological environment and serious water and soil loss.With the implementation of ecological restoration projects such as GGP,the vegetation coverage of the Loess Plateau is significantly improved,which will change the carbon sequestration capacity of the ecosystem.Therefore,scientific and accurate assessment of carbon storage and prediction of carbon sequestration potential,as well as its spatial distribution and driving factors have a certain guiding effect on the formulation and implementation of ecological restoration and protection policies and carbon sequestration measures in the Loess Plateau.Based on the measured data of carbon density samples in the Loess Plateau,this study used Kriging spatial interpolation method to map the spatial distribution of carbon density in different ecosystems and estimate the status of carbon storage in the Loess Plateau.Based on the dataset of climate,topography,vegetation,soil and other environmental factors in the Loess Plateau,the main controlling factors and their contribution of the spatial patterns of carbon pool are analyzed by correlation analysis and path analysis.Based on the current carbon storage map of the Loess Plateau,the study had estimated the maximum carbon storage of the ecosystem can under the condition that the environmental factors and land use patterns remain unchanged and predicted its carbon sequestration potential,so as to provide a scientific basis for coping with climate change and serving regional carbon neutral goals.The main conclusions are as follows:(1)The status and spatial patterns of carbon storages on the Loess Plateau.The total carbon storage of forest,grassland and cropland in the Loess Plateau is about 2.265 Pg,and the aboveground biomass,background biomass and soil organic carbon storage were 0.422 Pg,0.319 Pg and 1.524 Pg,respectively.Forest,grassland,cropland ecosystem carbon were 0.978 Pg,1.086 Pg,and 0.205 Pg,between various bioclimatic zones,Ⅰ > Ⅱ > Ⅲ > Ⅳ > Ⅴ,different ecosystem carbon spatial patterns were in gradually reduce from southeast to northwest of the Loess Plateau,the spatial pattern of the grassland ecosystem was more similar to it.Moreover,the spatial pattern of carbon storage in forest and grassland ecosystems was mainly determined by the spatial distribution of soil organic carbon pool.(2)The factors affected on the spatial patterns of carbon pools on the Loess Plateau.Climate(mean annual temperature,mean annual precipitation),elevation,topography(slope),soil texture(clay content)and NDVI explained 12%,8%,44% and32% of the spatial variation of aboveground biomass carbon pool,background biomass carbon pool,non-cropland soil organic carbon pool and cropland soil organic carbon pool,respectively.The elevation had the greatest influence on aboveground biomass carbon pool,which also has the greatest direct and total effects.For the background biomass carbon pool,mean annual temperature had the largest effect.Mean annual precipitation has the greatest influence on the total SOC pool in non-cropland soil,but elevation had the greatest direct effect.For cropland soil organic carbon pool,soil clay content is the most important factor.(3)Carbon sequestration potentials and their spatial patterns on the Loess Plateau.The maximum carbon storage and carbon sequestration potential of the ecosystem in the Loess Plateau is about 4.42 Pg and 2.155 Pg,respectively.The carbon sequestration potential of aboveground biomass carbon pool,background biomass carbon pool and soil organic carbon pool are 0.420 Pg,0.319 Pg and 1.417 Pg,respectively,and soil carbon pool contributed the most to carbon sequestration potential.The carbon sequestration potentials of forest,grassland and cropland are 0.957 Pg,1.103 Pg and 0.091 Pg,respectively.In other words,the carbon sequestration potentials were mainly in the forest and grassland ecosystems in the Loess Plateau,and the grassland was slightly higher than the forest ecosystem.The carbon sequestration potential and carbon sequestration potential index of region Ⅱ are the highest among all bioclimatic regions.The spatial pattern of the maximum carbon storage in the Loess Plateau is similar to the status of carbon storage,which decreases gradually from southeast to northwest,but its spatial distribution is more continuous.The spatial pattern of carbon sequestration potential index and the spatial pattern of carbon storage show an opposite trend in most regions.In conclusion,although the ecological environment of the Loess Plateau has been restored to some extent,its carbon density level was still lower than the national average carbon density,and the spatial distribution is extremely uneven.In the future,in order to improve the carbon sequestration potential of ecosystems,we should take into account the spatial heterogeneity of carbon sequestration potential of different ecosystems in different regions of the Loess Plateau,comprehensively consider the local environmental conditions,formulate management measures according to local conditions,gradually realize the refined management of ecosystems,and make greater contributions to the construction of ecological civilization in China.