土壤生物对地上生物的反馈作用及其机制

Feedback mechanisms of soil biota to aboveground biology in terrestrial ecosystems

长期以来对陆地生态系统的研究主要集中于地上部分。由于测度上的困难,人们对地下部分(belowground)的认识还处于相当模糊的状态。当今的生态学家已经越来越强烈地认识到,地上生态系统与地下生态系统存在着不可分割的相互联系。100多年来的研究表明,作为地下生态系统最活跃部分的土壤生物,是联结地上部分与地下部分物质循环和能量流动的纽带,对地上部分的结构、功能及过程起着重要的反馈调控作用。土壤生物受资源的时空异质性、营养的可获得性以及非生物因素的选择性所驱动,通过直接作用于根系,或通过改变养分的矿化速率及其在土壤中的空间分布,改变植物根际的激素状况以及土壤环境等间接作用方式,对地上生物产生正、负反馈作用。因此,从土壤生物和地上生物的相互作用过程、土壤生物功能群及土壤食物网等角度分析土壤生物反馈作用的时空尺度、生物组织形式、方式、模型、驱动因素及其机制,能为理解地下生态学过程、维持生态系统稳定性以及制定生物多样性保护策略提供参考,并有助于理解全球变化下陆地生态系统结构及功能的动态和响应过程。

Much attention has been paid to the studies of aboveground biological processes in terrestrial ecosystems. Mutual feedbacks between aboveand belowground processes have recently become a central interest of ecologists. Soil biota, the most active portion in belowground systems, play crucial roles in processes such as nutrient cycling and energy transformation in terrestrial ecosystems. Soil biota, driven by resource heterogeneity, nutrient availability, and abiotic conditions, could impose direct or indirect and positive or negative feedbacks on aboveground biology by altering rates of nutrient mineralization and the spatial distribution of nutrient availability, rhizospheric hormones and the soil environment. We analyze spatial and temporal variations in soil functional diversity, soil foodweb structure, and the above-and belowground interactions across a wide range of terrestrial ecosystems. These analyses will improve our understanding of belowground ecological processes, and inform the management of ecosystem stability and biodiversity conservation in response to global changes.