Halving sunlight reveals no carbon limitation of aboveground biomass production in alpine grassland
JournalArticle (Originalarbeit in einer wissenschaftlichen Zeitschrift)
ID
4525567
Author(s)
Moehl, Patrick; Hiltbrunner, Erika; Koerner, Christian
Author(s) at UniBasel
Möhl, Patrick Hiltbrunner, Erika Körner, Christian
Year
2020
Title
Halving sunlight reveals no carbon limitation of aboveground biomass production in alpine grassland
Journal
Global change biology
Volume
26
Number
3
Pages / Article-Number
1857-1872
Mesh terms
Biomass; Carbon; Grassland; Plant Physiological Phenomena; Sunlight
Abstract
In temperate alpine environments, the short growing season, low temperature and a slow nutrient cycle may restrict plant growth more than carbon (C) assimilation does. To test the C-limitation hypothesis, we applied a shade gradient ranging from ambient light to 44% (maximum shade) of incident photon flux density (PFD) in late successional, Carex curvula dominated alpine grassland at 2,580m elevation in the Swiss central Alps for three years (2014-2016). Total aboveground biomass did not significantly decrease under reduced PFD, with a confidence interval reaching from+4% to -15% biomass in maximum shade. Belowground biomass, consisting to more than 80% of fine roots, was significantly reduced by a mean of 17.9±4.6% (± SE), corresponding to 228g/m2 , in maximum shade in 2015 and 2016. This suggests reduced investments into water and nutrient acquisition according to the functional equilibrium concept. Specific leaf area (SLA) and maximum leaf lengths of the most abundant species increased with decreasing PFD. Foliar concentration of non-structural carbohydrates (NSC) was reduced by 12.5±4.3% under maximum shade (mean of eight tested species), while NSC concentration of belowground storage organs were unchanged in the four most abundant forbs. Further, maximum shade lowered foliar delta13 C by 1.56±0.35 and increased foliar nitrogen concentrations per unit dry mass by 18.8±4.1% across six species in 2015. However, based on unit leaf area, N concentrations were lower in shade (effect of higher SLA). Thus, while we found typical morphological and physiological plant responses to lower light, shading did not considerably affect seasonal aboveground biomass production of this alpine plant community within a broad range of PFD. This suggests that C is not a growth limiting resource, matching the unresponsiveness to in situ CO2 enrichment previously reported for this type of grassland.© 2019 John Wiley & Sons Ltd.
ISSN/ISBN
1365-2486
edoc-URL
https://edoc.unibas.ch/78147/
Full Text on edoc
No
Digital Object Identifier DOI
10.1111/gcb.14949
PubMed ID
http://www.ncbi.nlm.nih.gov/pubmed/31799736
ISI-Number
000509573900001
Document type (ISI)
Journal Article
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