氮沉降对土壤线虫群落影响的研究进展

综述了主要陆地生态系统(草原、农田和森林)土壤线虫群落对氮沉降增加的响应格局和机制。总体上,氮沉降增加对线虫数量一般无显著影响,但增加了土壤中富集机会主义者(即低营养级的r-策略者)数量,降低了线虫群落成熟度指数(MI),表明氮沉降增加可能会使土壤食物网简化。氮沉降增加主要通过改变土壤微环境(如增加含氮离子浓度、降低土壤pH)直接影响土壤线虫群落,或者改变植物地上地下资源的输入和线虫与其他土壤动物的关系,间接影响线虫群落。最后,根据目前研究现状,指出了当前研究存在的局限性,包括研究时间和空间尺度上以及研究技术手段上的局限。建议综合多个全球环境变化因子,并结合室内试验及分子手段的方法对土壤线虫群落进行研究。

Advances in Effect of Nitrogen Deposition on Soil Nematode Communities

The increase of nitrogen deposition has altered ecosystem structure and function. As key bioindicators of soil ecosystems, soil nematodes have important ecological implications. With the globalization of nitrogen deposition, it has attracted widespread attention on how elevated nitrogen inputs affect soil nematode. The response pattern and mechanism of soil nematodes to elevated nitrogen deposition in terrestrial ecosystems (grassland, farmland and forests) were reviewed. In general, elevated nitrogen deposition had no significant effects on the number of soil nematodes, but increased the number of enrichment opportunist (i.e. r-strategy nematodes with low trophic levels) and decreased soil nematode maturity index (MI), indicating that the increase of nitrogen inputs might simplify soil food webs. Moreover, elevated nitrogen deposition could affect the soil nematode community directly by changing soil microenvironment, such as increased NH₄⁺ and NO₃^- concentration and decreased soil pH, or indirectly by changing plant resource inputs and the relationships between the nematodes and other soil biota. In the end, some limitations of previous studies were pointed out, including temporal and special scales, and measurement techniques. To better understand the effects of global environmental changes, it is urgent to explore how multiple global change factors affect soil nematode communities across different terrestrial ecosystems. It was suggested to combine both molecular biology techniques and laboratory incubation methods in the future.