中国森林生态系统土壤CO2释放分布规律及其影响因素

联合国气候框架公约的签署提升了人们对全球变暖、碳循环变化的关注。陆地生态系统在全球变暖格局下的地位与作用，尤其是土壤碳库对全球变暖格局的响应是全球变化研究的焦点。土壤CO₂释放作为土壤-大气CO₂交换的主要途径之一，也就成为各国生态学家研究的重点内容。在对我国森林生态系统CO₂释放通量以及相关气候、生物等因子的资料进行收集、整理和分析的基础上，探讨了我国森林生态系统土壤CO₂释放的分布规律，以及这种规律性分布的气候、生物影响因素。对于我国这样一个南北跨度大的国家，不同区域的森林生态系统土壤CO₂释放通量间存在较大的差异，在全国尺度上，森林生态系统土壤CO₂释放通量平均值为(1.79 ± 0.86) g C m^-2 d^-1，而且土壤CO₂释放通量随着纬度增加逐渐降低。作为一个复杂的生态过程，土壤CO2释放受到生物、非生物因子或独立、或综合的影响。通过分析指出，在全国尺度上，年均温、降雨量、群落净生产力及凋落物量显著地影响森林土壤CO₂释放通量。同时，也正是这些影响因子的纬度分布，导致了我国森林生态系统土壤CO₂释放通量的纬度分布规律。作为衡量土壤CO₂释放对温度敏感性的重要指标，计算了我国森林生态系统土壤CO2释放温度敏感性系数-Q₁₀值，约为1.5，该值显著低于全球平均水平，2.0。

Soil CON efflux of forest ecosystem in China: distribution and controlling factors

The observed increase in levels of atmospheric CO₂ and the signing of the UN Framework Convention on Climate Change have increased interest in the global warming and the global carbon cycle. What the role of terrestrial ecosystems plays in the pattern of the global change is one of studied hotspots. As one of the key components in the global carbon cycle, released CO₂ from soil is one of the major pathways to exchange CO₂ between soil and atmosphere, which is second only to gross primary productivity. Therefore, the response of soil carbon pool to the global warming is another studied focus issue in the recent years. In this paper, relative information of soil CO₂ efflux and climatic, biotic factors of forest ecosystem in China were collated from published studies, then the distribution of soil CO₂ efflux of forest ecosystems and its correlations to these factors were identified. Not only the studied forest ecosystems varied in composition and function, but also soil CO₂ efflux of these forest ecosystems differed significantly. On national scale, the averaged soil CO₂ efflux of forest ecosystems was (1.79±0.86) g C m^-2 d^-1, and declined gradually from the lower latitude to higher latitude. As a complex ecological process, many biotic and abiotc factors could influence soil CO₂ efflux independently or interactively. By the means of distinguishing the responses of soil CO₂ efflux to temperature, precipitation, productivity and litterfall, this paper suggested these factors affected soil CO₂ efflux positively on national scale. Furthermore, the distribution of soil CO₂ efflux on national scale was due to the distribution of climatic and biotic factors just about. The temperature sensitivity of soil CO₂ efflux in forest ecosystem in China, Q₁₀ value, was estimated. It was 1.5 and much lower than the global averaged value, 2.0.