湖南省植被碳汇动态及其自然驱动因子分析

Dynamic and natural driving factors of vegetation carbon sink in Hunan Province

净生态系统生产力(net ecosystem productivity,NEP)是生态系统极为重要的特征量,也是陆地生态系统与大气之间碳交换的物理量。该文基于MODIS NPP和气象数据,利用土壤微生物呼吸模型估算2000—2020年湖南省的植被NEP,并结合趋势拟合、变异系数和标准差椭圆等方法对植被碳汇动态变化特点进行分析,进而利用地理探测器和相关分析等方法定量分析自然因子对植被碳汇的影响。结果表明:湖南省植被碳汇多年平均值为603.01 gC·m^(-2)·a^(-1),呈现出南高北低、西高东低,由西南向东北逐步降低的空间分布格局;2000—2020年,植被碳汇平均趋势系数为2.97 gC·m^(-2)·a^(-1),整体呈现增加趋势;变异系数以低波动和较低波动为主,高波动地区主要分布于部分城市周边容易受到自然或人为因素干扰的区域;植被碳汇变化是多因子共同作用的结果,各因子解释力依次为:海拔>坡度>气温>降水量>坡向,海拔和坡度对湖南省植被碳汇的时空分布具有较强的解释力,气温和降水对植被碳汇的解释力较弱,植被碳汇与气温、降水量正相关的区域分别占植被总面积的75.13%和73.11%。研究结果可为该区域生态文明建设和实现“双碳”目标提供科学参考。

Net ecosystem productivity(NEP)is recognized as an important characteristic quantity of ecosystems and a physical quantity of carbon exchange between terrestrial ecosystems and the atmosphere.Utilizing MODIS NPP and meteorological data,this study estimated the vegetation NEP in Hunan Province from 2000 to 2020 using a soil microbial respiration model.Furthermore,this study analyzed the dynamic characteristics of vegetation carbon sink through trend analysis,variation coefficient,and standard deviation ellipse methods,followed by a quantitative assessment of the impacts of natural factors on vegetation carbon sink using geographical detectors and correlation analysis.The results indicate that the annual multiyear average of vegetation carbon sink in Hunan Province was 603.01 gC·m^(-2)·a^(-1).The vegetation carbon sink presented a spatial distribution pattern of higher values in the south and west and lower values in the north and east,decreasing gradually from southwest to northeast.From 2000 to 2020,the average trend coefficient of vegetation carbon sink was 2.97 gC·m^(-2)·a^(-1),trending upward overall.The coefficient of variation was primarily characterized by small fluctuations and fairly small fluctuations,while areas of great fluctuations are mainly scattered around certain cities,which are more susceptible to natural or anthropogenic disturbances.The variations in vegetation carbon sink in Hunan Province result from multiple factors,with the explanatory power of various factors decreased in the order of altitude,slope,temperature,precipitation,and slope.Both altitude and slope exhibited strong explanatory power regarding the spatiotemporal distribution of vegetation carbon sink in Hunan Province,while temperature and precipitation demonstrated weaker explanatory power.Areas where vegetation carbon sink was positively correlated with temperature and precipitation accounted for 75.13%and 73.11%of the total vegetation area,respectively.