森林净生态系统生产力及其生物影响因子研究进展

Effects of biotic factors on net ecosystem production in forests: A review

在全球大气二氧化碳浓度上升的背景下,陆地生态系统碳循环及碳汇功能研究得到了广泛的关注,日益成为今后的政治和外交的重大议题之一。净生态系统生产力(net ecosystem production,NEP)是生态系统光合固定的碳与生态系统呼吸损失的碳之间的差值;或者为生态系统净的碳积累速率。NEP的研究整合生态系统地上和地下部分,把生态系统碳循环的影响因子有机地联系了起来。当NEP为正值时,说明生态系统为碳汇,NEP为负值则表明生态系统为碳源。随着植物和土壤相互联系及其对生态系统过程研究的深入,NEP已经成为生态系统碳循环研究的核心概念之一。以森林NEP为出发点,综述了国内外的最近的NEP研究进展,分析了NEP研究的科学意义;探讨了植物群落组成/生物多样性、土壤微生物群落、大型/土壤动物和人为的管理或干扰等生物因子对NEP的影响。根据综述研究提出未来研究应在:(1)土壤生物过程、土壤食物网及其与地上部分植物/动物相互作用对NEP的影响;(2)自然林生物多样性的竞争/共存机制与生态系统碳吸存稳定性;(3)人工林固碳潜力和不同植物功能群(灌草层)对生态系统碳动态影响等方面加强,以期为全面认识生物因子对森林生态系统系统固碳现状、机制和潜力提供理论基础。

Under the background of global change, carbon cycling and carbon sequestration in terrestrial ecosystems have attracted considerable attention, which has become one of the important politic and diplomatic agendas. Net ecosystem production （NEP） is defined as the difference between ecosystem-level photosynthetic gain of carbon （gross primary production, GPP） and ecosystem loss of carbon （ecosystem respiration）; or the net rate of carbon accumulation in ecosystems. NEP links above- and below-ground components which allow us to understand the carbon cycling in a complex ecosystem. Because the biotic linkages between plant and soil have been considered as the important driver for ecosystem properties and processes, NEP is considered as a central concept in ecosystem carbon cycling. When the NEP value is positive, it indicates the ecosystem is carbon sink; while the NEP value is negative, it indicates the ecosystem is carbon source. The paper reviewed the major findings of NEP in recent years. We highlighted the scientific importance of NEP research firstly, and then discussed the effects of plant community composition/plant diversity; soil microbial communities; macro/soil fauna activities and human activities/disturbance on NEP. The future challenges in the NEP studies also were discussed and the important topics that should be paid more attention aspects including were listed as following： （1） Effects of soil biological processes, soil food web and their interactions with plant communities on NEP; （2） Mechanisms of competitive/coexistence for plant communities in natural forests and their effects on ecosystem carbon sequestration; （3） Potential carbon sequestration of plantations and the contributions of different functional groups to ecosystem carbon dynamics. This review provides a theoretical foundation for a comprehensive understanding of the effects of biological factors on the status, mechanisms and potential of net ecosystem production in forests.