Hiltbrunner Erika, Aerts Rien, Bühlmann Tobias, Huss-Danell Kerstin, Magnusson Borgthor, Myrold David D, Reed Sasha C, Sigurdsson Bjarni D, Körner Christian
Department of Environmental Sciences, Institute of Botany, University of Basel, Schönbeinstrasse 6, 4056, Basel, Switzerland,
Oecologia. 2014 Sep;176(1):11-24. doi: 10.1007/s00442-014-2991-x. Epub 2014 Jun 18.
Research in warm-climate biomes has shown that invasion by symbiotic dinitrogen (N2)-fixing plants can transform ecosystems in ways analogous to the transformations observed as a consequence of anthropogenic, atmospheric nitrogen (N) deposition: declines in biodiversity, soil acidification, and alterations to carbon and nutrient cycling, including increased N losses through nitrate leaching and emissions of the powerful greenhouse gas nitrous oxide (N2O). Here, we used literature review and case study approaches to assess the evidence for similar transformations in cold-climate ecosystems of the boreal, subarctic and upper montane-temperate life zones. Our assessment focuses on the plant genera Lupinus and Alnus, which have become invasive largely as a consequence of deliberate introductions and/or reduced land management. These cold biomes are commonly located in remote areas with low anthropogenic N inputs, and the environmental impacts of N2-fixer invasion appear to be as severe as those from anthropogenic N deposition in highly N polluted areas. Hence, inputs of N from N2 fixation can affect ecosystems as dramatically or even more strongly than N inputs from atmospheric deposition, and biomes in cold climates represent no exception with regard to the risk of being invaded by N2-fixing species. In particular, the cold biomes studied here show both a strong potential to be transformed by N2-fixing plants and a rapid subsequent saturation in the ecosystem's capacity to retain N. Therefore, analogous to increases in N deposition, N2-fixing plant invasions must be deemed significant threats to biodiversity and to environmental quality.
对温暖气候生物群落的研究表明，共生固氮植物的入侵能够以类似于人为大气氮沉降所导致的方式改变生态系统：生物多样性下降、土壤酸化以及碳和养分循环的改变，包括通过硝酸盐淋溶导致的氮损失增加以及强大的温室气体氧化亚氮（N₂O）排放增加。在此，我们采用文献综述和案例研究方法，评估北方、亚北极和山地温带高海拔生活带的寒冷气候生态系统中类似转变的证据。我们的评估聚焦于羽扇豆属和桤木属植物，它们在很大程度上因有意引入和/或土地管理减少而成为入侵物种。这些寒冷生物群落通常位于人为氮输入较低的偏远地区，固氮植物入侵对环境的影响似乎与高氮污染地区人为氮沉降的影响一样严重。因此，固氮作用输入的氮对生态系统的影响可能与大气沉降输入的氮一样显著甚至更强，寒冷气候中的生物群落也不例外，同样面临被固氮物种入侵的风险。特别是，这里研究的寒冷生物群落既显示出被固氮植物改变的强大潜力，也显示出生态系统保留氮的能力随后迅速饱和。因此，与氮沉降增加类似，固氮植物入侵必须被视为对生物多样性和环境质量的重大威胁。
