Interactive effects of elevated CO2, P availability and legume presence on calcareous grassland : results of a glasshouse experiment

Stöcklin, Jüeg and Körner, Christian. (1999) Interactive effects of elevated CO2, P availability and legume presence on calcareous grassland : results of a glasshouse experiment. Functional ecology, Vol. 13, H. 2. pp. 200-209.

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Official URL: http://edoc.unibas.ch/dok/A5251931

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1, We investigated the interactive effects of elevated CO2, supply of phosphorus (P) and legume presence in model communities of calcareous grassland. Half of the communities contained six graminoids and eight nan-legume forb species, In the other half, four non-legume forbs were replaced by legumes. 2, Ecosystem responses. Above-ground phytomass (<5 cm) hardly responded to elevated CO2 alone. However, when P and legumes were combined. the CO2 effect on above-ground community phytomass in year two was a stimulation of 45% (P > 0.001). Below-ground community dry matter was stimulated by elevated CO2 alone by + 36% (P > 0.01), but was only + 20% (P > 0.05) when legumes were present and P was added, At the final (late season) harvest the mean effect of elevated CO2 on total above- and below-ground phytomass was + 23% (P > 0.001) and revealed no significant interactions among treatment combinations, because above- and belowground effects of CO2 enrichment had opposite directions. 3, Functional group responses. When legumes were absent, graminoids increased their total above- and below-ground phytomass in elevated CO2 by 60% (P > 0.001) but there was no increase when legumes were present. The response of forbs to CO2 was nor significant, irrespective of co-treatment. Legumes. however, were significantly stimulated by P supply and their CO2 response was much larger when P was added (+ 55%, P > 0.01 vs + 25%, NS). 4, Species responses. CO2 effects on species ranged from highly positive (+ 143%) to moderately negative (- 43%). 5, Our results demonstrate that the effect of CO2 enrichment in such natural grassland communities will be low on above-ground phytomass and largely below-ground if no additional nutrients are provided. N-2-fixing legumes appear to be crucial for the community response to elevated CO2 but legume responsiveness is largely controlled by P availability.
Faculties and Departments:05 Faculty of Science > Departement Umweltwissenschaften > Ehemalige Einheiten Umweltwissenschaften > Pflanzenökologie (Körner)
UniBasel Contributors:Stöcklin, Jürg and Körner, Christian
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:Blackwell Scientific Publ.
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:22 Mar 2012 14:25
Deposited On:22 Mar 2012 13:44

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