| As the largest global carbon pool,terrestrial ecosystem play a key role in global climate change and carbon cycle processes.Regional land use change affects the carbon emission and carbon sink process of terrestrial ecosystem,which is an important factor affecting the global terrestrial ecosystem carbon stock and carbon sequestration function.Zhongtiao Mountain is located in the transition area from Loess Plateau to North China Plain,which is a key area for national forest protection,and the rich vegetation resources mean that it has great carbon sink potential.In recent years,due to human activities and climate change,the regional ecosystem and land use types have changed,which in turn has led to changes in the regional terrestrial ecosystem carbon stocks.Terrestrial ecosystems play an important role as carbon sinks in achieving indirect emission reduction,and exploring the characteristics of terrestrial ecosystem carbon storage is of great significance for promoting regional low-carbon construction and achieving regional"peak carbon and carbon neutrality"goals.In this study,the annual land use data of Zhongtiao Mountain from 2000 to 2020were used to analyze the spatial and temporal changes and transfer characteristics of land use;the carbon stock estimation module of InVEST model was used to analyze the spatial and temporal distribution characteristics of terrestrial ecosystem carbon stocks,and the results were corrected by estimating the net ecosystem productivity(NEP)of vegetation in Zhongtiao Mountain;finally,correlation analysis and geographic detector were used to analyze the driving factors of carbon storage changes and spatial differentiation in Zhongtiao Mountain.The main conclusions are as follows:(1)From 2000 to 2020,significant spatial and temporal changes in land use were observed in Zhongtiao Mountain.The main land types in the study area were forest,farmland,grassland,and construction land,with forest being the largest,accounting for more than 50%of the total area of the study area,followed by farmland,which accounted for more than 35%of the study area.From 2000 to 2020,the forest,farmland,and construction land areas in Zhongtiao Mountain increased,while the grassland area decreased significantly by 54.4%,and the decreased area was mainly converted into farmland and forest,with the increase in construction land area mainly coming from the conversion of farmland.Land use conversions between different years were relatively frequent,with conversions between farmland and grassland and between farmland and forest being more frequent.(2)From 2000 to 2020,the revised carbon stock of the terrestrial ecosystem in Zhongtiao Mountain exhibited a fluctuating pattern of"first increasing,then decreasing,and then increasing",with an overall increasing trend.The carbon stock increased by a total of 2.296×10~6 t,with a multi-year average carbon stock of 7.979×10~7 t.The spatial distribution pattern of the revised carbon stock was not significantly different from that before revision,and showed an"east high and west low"spatial distribution characteristic.The high carbon stock area was mainly concentrated in the eastern,central,and northwestern parts,while the low carbon stock area was distributed in the southwestern and central small regions.The spatial distribution was mainly determined by land use types and vegetation distribution.Regions with higher carbon stocks had a larger proportion of forests,while regions with lower carbon stocks had a relatively higher proportion of construction land.From 2000 to 2020,the carbon summary value of terrestrial ecosystems in Zhongtiao Mountain shows a fluctuating upward trend,with a multi-year average NEP of 3.837×10~5 t C/a and a total of 8.057×10~6 t C fixed during the period;The annual unit area NEP was 0.060 kg C/(m~2·a),indicating a carbon sink characteristic in the region as a whole.There were significant spatial differences in the distribution of NEP,and there was a spatial positive correlation.Overall,the NEP was high in the northeast and low in the northwest,with carbon sinks mainly distributed in the northeast and carbon sources in the central and northwestern regions.(3)The spatial and temporal variation of carbon storage in the Zhongtiao Mountain terrestrial ecosystem is jointly influenced by natural and social factors.Correlation analysis between the carbon storage of the Zhongtiao Mountain terrestrial ecosystem and temperature,precipitation,potential evapotranspiration,normalized difference vegetation index(NDVI),population,and human activity intensity(HAILS)from 2000to 2020 showed that carbon storage changes were positively correlated with NDVI and temperature,and negatively correlated with precipitation,potential evapotranspiration,population,and HAILS.The proportion of significant correlation area was highest for HAILS,followed by population and NDVI,accounting for 43.3%,18.9%,and 16.5%of the total area,respectively,indicating that social factors such as human activity intensity and population had a significant impact on carbon storage changes in the Zhongtiao Mountain area over the past 20 years.Geographic detection analysis of the relationship between the carbon storage of the Zhongtiao Mountain terrestrial ecosystem and driving factors showed that different driving factors had significant differences in their impact on spatial differentiation of carbon storage.NDVI,human activity intensity,and potential evapotranspiration were the primary factors influencing carbon storage spatial differentiation,followed by temperature,population,and elevation,while slope,aspect,and precipitation had relatively small effects.The interaction of different factors had a dual-factor enhancement and nonlinear enhancement effect on carbon storage,with the interaction effect between NDVI and human activity intensity having the largest impact,indicating that the spatial differentiation of carbon storage was the result of the joint action of natural and human factors.In ecological environment protection and regional low-carbon construction in Zhongtiao Mountain,it is necessary to comprehensively consider the characteristics of different influencing factors,adopt differentiated ecological regulation models and strategies,improve the stability of the ecosystem,and enhance carbon storage capacity. |
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