东亚森林、草地碳利用效率及碳通量空间变化的影响因素分析

森林和草地是陆地生态系统的重要组成部分,研究整合基于涡度相关法观测碳通量的已发表文献,共选取东亚地区40个拥有1年以上数据的通量站(森林26个,草地14个),分析碳利用效率(CUE)以及净生态系统生产力(NEP)、总生态系统生产力(GEP)、生态系统呼吸(RE)的空间变异特征及其影响因素。东亚地区的森林和草地为碳汇,且森林的碳汇显著高于草地(p0.001),其NEP分别为328.64±256.46gC/(m~2·a),63.43±42.99gC/(m~2·a)。森林和草地的CUE分别为0.21,0.20,影响森林CUE变化的因素主要是林龄,呈线性负相关关系(p0.001)。影响草地CUE的因素主要是年均降水量(MAP),呈线性负相关关系(p0.05)。森林和草地的GEP,RE均是随纬度的升高而线性降低,NEP与纬度呈现二次函数关系,随纬度升高而先升高后降低。森林和草地的GEP,RE都与MAP呈线性正相关关系,且NEP与MAP呈先升高后降低的二次函数关系,其中森林和草地的饱和降水量大约为1 300mm和390mm。森林的GEP,RE与年均温(MAT)呈现线性正相关关系。森林和草地的GEP,RE与增强型植被指数(EVI)呈线性正相关关系。

Factors Affecting the Spatial Variation of Carbon Use Efficiency and Carbon Fluxes in East Asian Forest and Grassland

Forest and grassland play an essential role in the terrestrial ecosystem.The objective of this study is to analyze the spatial variation characteristics and influence factors of carbon use efficiency (CUE),gross ecosystem production (GEP),ecosystem respiration (ER),and net ecosystem production (NEP) based on more than one year data which were obtained from 40 sites (26 forest sites,14 grassland sites) in the East Asian region from published literatures.Forest and grassland in the East Asian region both exhibit carbon sinks,while forest showed significantly higher value than grassland (p＜0.001).The average NEP in forest and grassland in the East Asian are 328.64±256.46 gC/(m2 · a) and 63.43±42.99 gC/(m2 · a),respective ly.The average CUE in forest and grassland are 0.21 and 0.20 in this region,CUE of forest is negatively correlated with the forest age and mean annual precipitation (MAP),respectively.The results show that GEP and ER in forest grassland linearly decrease with an increase in latitude.In addition,relationship between NEP and latitude can be described by quadratic function.There is a clear linear relationship between GEP,ER with MAP in both forest and grassland.The results also show that MAP and NEP first increase and then decrease with a quadratic function relationship,NEP is the maximum when amounts precipitation are 1 300 mm and 390 mm for forest and grassland,respectively.GEP and ER in forest show a positive relationship with mean annual temperature.Moreover,GEP and RE in both forest and grassland showed a positive linear correlation with vegetation index.