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Species‐level effects more important than functional group‐level responses to elevated CO 2 : evidence from simulated turves
Author(s) -
HANLEY M. E.,
TROFIMOV S.,
TAYLOR G.
Publication year - 2004
Publication title -
functional ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.272
H-Index - 154
eISSN - 1365-2435
pISSN - 0269-8463
DOI - 10.1111/j.0269-8463.2004.00845.x
Subject(s) - biology , biomass (ecology) , forb , mesocosm , lotus corniculatus , nutrient , plant community , grassland , grazing , ecosystem , agronomy , botany , zoology , ecology , species richness
Summary1 Using mixtures of 14 calcareous grassland plant species drawn from three functional groups, we looked at the effects of elevated atmospheric CO 2 on contrasting levels of ecosystem performance (species, functional group and community). Experimental communities were subjected to ambient (≈350 µmol mol −1 ) or elevated CO 2 (≈600 µmol mol −1 ) in controlled environments, with grazing simulated by clipping at monthly intervals for 546 days. 2 We assessed the effect of elevated CO 2 on plant performance by quantifying the productivity (biomass) and cover of component species. We also examined the effect of elevated CO 2 on the vertical structure of the plant canopy. Elevated CO 2 resulted in a significant increase in total community biomass only following nutrient addition. Within functional groups, non‐leguminous forb species had significantly greater biomass and cover in elevated CO 2 both before and after nutrient addition, although the effect was mainly due to the influence of one species ( Centaurea nigra ). Grasses, in contrast, responded negatively to elevated CO 2 , although again significant reductions in biomass and cover could mainly be ascribed to a single species ( Brachypodium pinnatum ). Legumes exhibited increased biomass and cover in elevated CO 2 (the effects being particularly marked for Anthyllis vulneraria and Lotus corniculatus ), but this response disappeared following nutrient addition. Vertical structure was little affected by CO 2 treatment. 3 We conclude that due to the idiosyncratic responses of individual species, the categorization of plants into broad functional groups is of limited use in guiding our understanding of the impacts of elevated atmospheric CO 2 on plant communities.