Reply to: Data do not support large-scale oligotrophication of terrestrial ecosystems.

Hiltbrunner et al. apply a reductionist approach to argue that the evidence for widespread terrestrial oligotrophication2 should be replaced with a two-factor explanation (growth dilution and depositional signatures) that does not invoke reductions in N availability, that is, the supply of N relativ...

Full description

Bibliographic Details
Main Authors: Craine,  Joseph M., Elmore, Andrew J., Wang, Lixin  , Boeckx, Pascal, Delzon, Sylvain, Fang, Yunting  , Gray, Alan  , Guerrieri , Rossella, Gundale, Michael J., Hietz , Peter, Nelson, David M.  , Peri, Pablo Luis, Templer, Pamela H., Werner, Christiane
Format: info:ar-repo/semantics/artículo
Language:Inglés
Published: Springer Nature 2021
Subjects:
Online Access:http://hdl.handle.net/20.500.12123/9044
https://www.nature.com/articles/s41559-019-0949-4
https://doi.org/10.1038/s41559-019-0949-4
Description
Summary:Hiltbrunner et al. apply a reductionist approach to argue that the evidence for widespread terrestrial oligotrophication2 should be replaced with a two-factor explanation (growth dilution and depositional signatures) that does not invoke reductions in N availability, that is, the supply of N relative to plant demand. Contrary to any “adjustment of leaf photosynthetic capacity and a widening of leaf C:N ratios,” there is little evidence that observed declines in foliar [N] are caused solely by photosynthetic downregulation. Photosynthetic downregulation is not universal and probably could be caused by reduced N availability. A comprehensive synthesis of data on responses of plant productivity and N acquisition to elevated CO2 in free-air carbon dioxide enrichment (FACE) experiments demonstrated that there were declines in N uptake in low-N ecosystems as a result of decreased ‘access’ to N, not reduced demand4. The growth dilution hypothesis was ‘refuted’ as an explanation for these declines.