Impacts of warming and elevated CO2 on a semi-arid grassland are non-additive, shift with precipitation, and reverse over time

It is unclear how elevated CO2 (eCO2) and the corresponding shifts in temperature and precipitation will interact to impact ecosystems over time. During a 7‐year experiment in a semi‐arid grassland, the response of plant biomass to eCO2 and warming was largely regulated by interannual precipitation,...

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Bibliographic Details
Published in:Ecology letters 2016-08, Vol.19 (8), p.956-966
Main Authors: Mueller, K. E., Blumenthal, D. M., Pendall, E., Carrillo, Y., Dijkstra, F. A., Williams, D. G., Follett, R. F., Morgan, J. A.
Format: Article
Language:English
Subjects:
Artemisia frigida
Bouteloua gracilis
C3 grass
C4 grass
Carbon Dioxide - chemistry
Carbon Dioxide - pharmacology
Climate Change
forb
Global warming
Grassland
Grasslands
Greenhouse gases
nitrogen
plant productivity
Precipitation
Rain
root biomass
soil moisture
Terrestrial ecosystems
Time Factors
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Summary:It is unclear how elevated CO2 (eCO2) and the corresponding shifts in temperature and precipitation will interact to impact ecosystems over time. During a 7‐year experiment in a semi‐arid grassland, the response of plant biomass to eCO2 and warming was largely regulated by interannual precipitation, while the response of plant community composition was more sensitive to experiment duration. The combined effects of eCO2 and warming on aboveground plant biomass were less positive in ‘wet’ growing seasons, but total plant biomass was consistently stimulated by ~ 25% due to unique, supra‐additive responses of roots. Independent of precipitation, the combined effects of eCO2 and warming on C3 graminoids became increasingly positive and supra‐additive over time, reversing an initial shift toward C4 grasses. Soil resources also responded dynamically and non‐additively to eCO2 and warming, shaping the plant responses. Our results suggest grasslands are poised for drastic changes in function and highlight the need for long‐term, factorial experiments.
ISSN:1461-023X
1461-0248
DOI:10.1111/ele.12634