森林生态系统细根周转规律及影响因素

根系周转是陆地生态系统碳循环的关键过程, 对研究土壤碳库变化及全球气候变化均具有重要意义。然而由于根系周转率的测量计算方法较多, 不同方法得出的结果差异较大, 且目前对全球区域尺度上森林生态系统根系周转的研究还不够充分, 使得全球森林生态系统根系周转变化规律仍不清楚。该研究通过收集文献数据并统一周转率计算方法, 对全球5种森林类型的细根周转空间格局进行整合, 同时结合土壤理化性质和气候数据, 得出影响森林生态系统细根周转的因子。结果表明, 不同森林类型细根周转率存在显著差异, 且随着纬度的升高逐渐降低; 森林生态系统细根周转率与年平均温度和年平均降水量呈正相关; 森林生态系统细根周转率与土壤有机碳含量呈正相关但与土壤pH值呈负相关。该研究为揭示森林生态系统细根周转规律及机制提供了科学依据。

Patterns and Influence Factors of Fine Root Turnover in Forest Ecosystems

Root turnover is a key process in the carbon cycle of terrestrial ecosystems, and plays an important role in studying soil carbon pool changes and global climate change. Various methods for measuring root turnover rate have been described, from which highly variable results are obtained. Moreover, the studies on root turnover in large regional scales are not sufficient, making the patterns of root turnover in global forest ecosystem still not clear. This study integrates the fine root turnover spatial pattern of five forest types in the world by collecting literature data and unifying the calculation method of turnover rate. Combined with soil physical and chemical properties and climate data, several factors driving the fine root turnover of forest ecosystems are obtained. We show that there was a significant difference in the different forest ecosystems and the fine root turnover rate almost decreased with the increase of latitude. The fine root turnover rate of forest ecosystems was positively correlated to the mean annual temperature and the mean annual precipitation. The fine root turnover rate of forest ecosystems was positively correlated to the soil organic carbon content but negatively correlated to soil pH. This study provides a model to study the fine root turnover laws and mechanisms of forest ecosystems.