Ecosystems ( IF 3.7 ) Pub Date : 2020-08-10 , DOI: 10.1007/s10021-020-00537-0 Xiao-Tao Lü , Shuang-Li Hou , Sasha Reed , Jiang-Xia Yin , Yan-Yu Hu , Hai-Wei Wei , Zhi-Wei Zhang , Guo-Jiao Yang , Zhuo-Yi Liu , Xing-Guo Han
Anthropogenic nitrogen (N) deposition has affected plant community composition and nutrient cycling in terrestrial ecosystems worldwide. This includes changes to the way plants use and recycle nutrients, including effects on nutrient resorption, which is a key process through which plants recover nutrients from tissue during senescence. Nutrient resorption has considerable adaptive and functional significance for plants and helps regulate core ecosystem processes such as decomposition. However, our understanding of how N deposition affects nutrient resorption and, in particular, of how N inputs alter ecosystem resorption via changes to existing species’ resorption compared with changes to community composition remains poor. To disentangle the role of species versus community composition controls driving variation in nutrient resorption responses to N inputs, we carried out an experiment with six different N addition rates in a temperate steppe. We found that species-scale nutrient resorption responses to N enrichment were variable; for example, only half of the measured species reduced both N and P resorption efficiency in response to increased N inputs. In contrast, community-scale responses consistently resulted in reduced N and P resorption. Still, N-induced changes in community composition were a weaker control on overall resorption responses than were the effects on individual species; however, it was the synergistic interaction between the two that resulted in the large total reductions of nutrient resorption in the face of increased N. Taken together, our results highlight that understanding and predicting nutrient resorption responses will be most accurately scaled by accounting not only for species’ reductions in resorption but also for changes in community composition.
中文翻译:
氮的富集通过改变物种吸收和植物群落组成来减少氮和磷的吸收
人为氮(N)的沉积已经影响了全球陆地生态系统中的植物群落组成和养分循环。这包括改变植物利用和循环利用养分的方式,包括对养分吸收的影响,这是植物在衰老过程中从组织中恢复养分的关键过程。营养吸收对植物具有重要的适应和功能意义,并有助于调节核心生态系统过程,例如分解。但是,我们对氮沉积如何影响养分吸收的理解,尤其是对氮输入如何通过改变现有物种的吸收而不是改变群落组成来改变生态系统吸收的了解仍然很少。弄清物种对群落组成控制着氮素输入对养分吸收响应的驱动变化,我们在温带草原进行了六种不同氮素添加量的实验。我们发现,物种尺度的养分吸收对氮富集的响应是可变的。例如,响应增加的氮输入,只有一半的被测物种同时降低了氮和磷的吸收效率。相反,社区尺度的反应始终导致氮和磷的吸收减少。尽管如此,氮诱导的群落组成变化对总体吸收反应的控制要弱于对单个物种的影响。然而,正是由于两者之间的协同作用,面对增加的氮素,营养吸收的总量大大减少了。总之,