High CO 2 dampens then amplifies N-induced diversity loss over 24 years.

Publisher: Nature Publishing Group Country of Publication: England NLM ID: 0410462 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1476-4687 (Electronic) Linking ISSN: 00280836 NLM ISO Abbreviation: Nature Subsets: MEDLINE

Publication: Basingstoke : Nature Publishing Group
Original Publication: London, Macmillan Journals ltd.

Atmosphere*/chemistry ; Biodiversity* ; Carbon Dioxide*/analysis ; Carbon Dioxide*/metabolism ; Grassland* ; Nitrogen*/metabolism ; Nitrogen*/analysis ; Plants*/classification ; Plants*/metabolism ; Plants*/radiation effects ; Soil*/chemistry; Biomass ; Light ; Time Factors

Rising levels of atmospheric carbon dioxide (CO 2 ) and nitrogen (N) deposition affect plant communities in numerous ways ^1-11 . Nitrogen deposition causes local biodiversity loss globally ^12-14 , but whether, and if so how, rising CO 2 concentrations amplify or dampen those losses remains unclear and is almost entirely unstudied. We addressed this knowledge gap with an open-air experiment in which 108 grassland plots were grown for 24 years under different CO 2 and N regimes. We initially found that adding N reduced plant species richness less at elevated than at ambient CO 2 . Over time, however, this interaction reversed, and elevated CO 2 amplified losses in diversity from enriched N, tripling reductions in species richness from N addition over the last eight years of the study. These interactions resulted from temporal changes in the drivers of diversity, especially light availability, that were in turn driven by CO 2 and N inputs and associated changes in plant biomass. This mechanism is likely to be similar in many grasslands, because additions of the plant resources CO 2 and N are likely to increase the abundance of the dominant species. If rising CO 2 generally exacerbates the widespread negative impacts of N deposition on plant diversity, this bodes poorly for the conservation of grassland biodiversity worldwide.
Competing Interests: Competing interests The authors declare no competing interests.
(© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

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142M471B3J (Carbon Dioxide)
N762921K75 (Nitrogen)
0 (Soil)

Date Created: 20241016 Date Completed: 20241114 Latest Revision: 20241119

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10.1038/s41586-024-08066-9

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