Ecologically implausible carbon response?
Magnani et al. present a very strong correlation between mean lifetime net ecosystem production (NEP, defined as the net rate of carbon (C) accumulation in ecosystems) and wet nitrogen (N) deposition. For their data in the range 4.9-9.8 kg N ha(-1) yr(-1), on which the correlation largely depends, the response is approximately 725 kg C per kg N in wet deposition. According to the authors, the maximum N wet deposition level of 9.8 kg N ha(-1) yr(-1) is equivalent to a total deposition of 15 kg N ha(-1 )yr(-1), implying a net sequestration near 470 kg C per kg N of total deposition. We question the ecological plausibility of the relationship and show, from a multi-factor analysis of European forest measurements, how interactions with site productivity and environment imply a much smaller NEP response to N deposition.
de Vries
Wim
W
Alterra, Wageningen University and Research Centre, PO Box 47, 6700 AA Wageningen, The Netherlands. wim.devries@wur.nl
Solberg
Svein
S
Dobbertin
Matthias
M
Sterba
Hubert
H
Laubhahn
Daniel
D
Reinds
Gert Jan
GJ
Nabuurs
Gert-Jan
GJ
Gundersen
Per
P
Sutton
Mark A
MA
D002244:Carbon / Q000378:metabolism*; D004463:Ecology; D017753:Ecosystem; D005060:Europe; D009584:Nitrogen / Q000378:metabolism; D014197:Trees / Q000378:metabolism
D002244:Carbon; D009584:Nitrogen