Functional structure mediates the responses of productivity to addition of three nitrogen compounds in a meadow steppe

Publikation: Bidrag til tidsskriftTidsskriftartikelfagfællebedømt

  • Jiangping Cai
  • Weiner, Jacob
  • Wentao Luo
  • Xue Feng
  • Guojiao Yang
  • Jiayu Lu
  • Xiao Tao Lü
  • Mai He Li
  • Yong Jiang
  • Xingguo Han

Atmospheric nitrogen (N) deposition is altering grassland productivity and community structure worldwide. Deposited N comes in different forms, which can have different consequences for productivity due to differences in their fertilization and acidification effects. We hypothesize that these effects may be mediated by changes in plant functional traits. We investigated the responses of aboveground primary productivity and community functional composition to addition of three nitrogen compounds (NH4NO3, [NH4]2SO4, and CO[NH2]2) at the rates of 0, 5, 10, 20 g N m−2 yr−1. We used structural equation modeling (SEM) to evaluate how functional structure influences the responses of productivity to the three N compounds. Nitrogen addition increased community-level leaf chlorophyll content but decreased leaf dry matter content and phosphorus concentration. These changes were mainly due to intra-specific variation. Functional dispersion of traits was reduced by N addition through changes in species composition. SEM revealed that fertilization effects were more important than soil acidification for the responses of productivity to CO(NH2)2 addition, which enhanced productivity by decreasing functional trait dispersion. In contrast, the effects of (NH4)2SO4 and NH4NO3 were primarily due to soil acidification, influencing productivity via community-weighted means of functional traits. Our results suggest that N forms with different fertilizing and acidifying effects influence productivity via different functional traits pathways. Our study also emphasizes the need for in situ experiments with the relevant N compounds to accurately understand and predict the ecological effects of atmospheric N deposition on ecosystems.

OriginalsprogEngelsk
TidsskriftOecologia
Vol/bind201
Sider (fra-til)575-584
ISSN0029-8549
DOI
StatusUdgivet - 2023

Bibliografisk note

Funding Information:
This work was financially supported by the National Natural Science Foundation of China (32271655, 32001386), Natural Science Foundation of Hebei Province (C2022201042), Major Special Science and Technology Project of Liaoning Province (2020JH1/10300006), and Natural Science Foundation of Liaoning Province (2020-BS-023).

Publisher Copyright:
© 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.

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