The impact of elevated CO2 on plant-herbivore interactions: experimental evidence of moderating effects at the community level.

DÍAZ, S; FRASER, L..H.; GRIME, J.P.; FALCZUK, V.

OECOLOGIA

SPRINGER

Lugar: Berlin; Año: 1998 vol. 117 p. 177 - 186

0029-8549

Surprisingly little research has been published on the responses to elevated [CO2] at the community level, where herbivores can select their preferred food. We investigated the combined e.ects of atmospheric [CO2] and herbivory on synthesised plant communities growing on soils of di.erent fertility. Factorial combi- nations of two [CO2] (350 or 700 ll l)1), two fertility (fertilised or non-fertilised), and two herbivory (herbi- vores present or absent) treatments were applied to a standard mixture of seven fast- and eight slow-growing plants in outdoor microcosms. The herbivores used were the grain aphid (Sitobion avenae) and the garden snail (Helix aspersa). We measured plant biomass, foliar nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca (Helix aspersa). We measured plant biomass, foliar nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca (fertilised or non-fertilised), and two herbivory (herbi- vores present or absent) treatments were applied to a standard mixture of seven fast- and eight slow-growing plants in outdoor microcosms. The herbivores used were the grain aphid (Sitobion avenae) and the garden snail (Helix aspersa). We measured plant biomass, foliar nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca (Helix aspersa). We measured plant biomass, foliar nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca growing on soils of di.erent fertility. Factorial combi- nations of two [CO2] (350 or 700 ll l)1), two fertility (fertilised or non-fertilised), and two herbivory (herbi- vores present or absent) treatments were applied to a standard mixture of seven fast- and eight slow-growing plants in outdoor microcosms. The herbivores used were the grain aphid (Sitobion avenae) and the garden snail (Helix aspersa). We measured plant biomass, foliar nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca (Helix aspersa). We measured plant biomass, foliar nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca (fertilised or non-fertilised), and two herbivory (herbi- vores present or absent) treatments were applied to a standard mixture of seven fast- and eight slow-growing plants in outdoor microcosms. The herbivores used were the grain aphid (Sitobion avenae) and the garden snail (Helix aspersa). We measured plant biomass, foliar nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca (Helix aspersa). We measured plant biomass, foliar nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca level, where herbivores can select their preferred food. We investigated the combined e.ects of atmospheric [CO2] and herbivory on synthesised plant communities growing on soils of di.erent fertility. Factorial combi- nations of two [CO2] (350 or 700 ll l)1), two fertility (fertilised or non-fertilised), and two herbivory (herbi- vores present or absent) treatments were applied to a standard mixture of seven fast- and eight slow-growing plants in outdoor microcosms. The herbivores used were the grain aphid (Sitobion avenae) and the garden snail (Helix aspersa). We measured plant biomass, foliar nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca (Helix aspersa). We measured plant biomass, foliar nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca (fertilised or non-fertilised), and two herbivory (herbi- vores present or absent) treatments were applied to a standard mixture of seven fast- and eight slow-growing plants in outdoor microcosms. The herbivores used were the grain aphid (Sitobion avenae) and the garden snail (Helix aspersa). We measured plant biomass, foliar nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca (Helix aspersa). We measured plant biomass, foliar nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca growing on soils of di.erent fertility. Factorial combi- nations of two [CO2] (350 or 700 ll l)1), two fertility (fertilised or non-fertilised), and two herbivory (herbi- vores present or absent) treatments were applied to a standard mixture of seven fast- and eight slow-growing plants in outdoor microcosms. The herbivores used were the grain aphid (Sitobion avenae) and the garden snail (Helix aspersa). We measured plant biomass, foliar nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca (Helix aspersa). We measured plant biomass, foliar nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca (fertilised or non-fertilised), and two herbivory (herbi- vores present or absent) treatments were applied to a standard mixture of seven fast- and eight slow-growing plants in outdoor microcosms. The herbivores used were the grain aphid (Sitobion avenae) and the garden snail (Helix aspersa). We measured plant biomass, foliar nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca (Helix aspersa). We measured plant biomass, foliar nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca 2] at the community level, where herbivores can select their preferred food. We investigated the combined e.ects of atmospheric [CO2] and herbivory on synthesised plant communities growing on soils of di.erent fertility. Factorial combi- nations of two [CO2] (350 or 700 ll l)1), two fertility (fertilised or non-fertilised), and two herbivory (herbi- vores present or absent) treatments were applied to a standard mixture of seven fast- and eight slow-growing plants in outdoor microcosms. The herbivores used were the grain aphid (Sitobion avenae) and the garden snail (Helix aspersa). We measured plant biomass, foliar nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca (Helix aspersa). We measured plant biomass, foliar nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca (fertilised or non-fertilised), and two herbivory (herbi- vores present or absent) treatments were applied to a standard mixture of seven fast- and eight slow-growing plants in outdoor microcosms. The herbivores used were the grain aphid (Sitobion avenae) and the garden snail (Helix aspersa). We measured plant biomass, foliar nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca (Helix aspersa). We measured plant biomass, foliar nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca growing on soils of di.erent fertility. Factorial combi- nations of two [CO2] (350 or 700 ll l)1), two fertility (fertilised or non-fertilised), and two herbivory (herbi- vores present or absent) treatments were applied to a standard mixture of seven fast- and eight slow-growing plants in outdoor microcosms. The herbivores used were the grain aphid (Sitobion avenae) and the garden snail (Helix aspersa). We measured plant biomass, foliar nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca nitrogen and soluble tannin concentration, aphid fe- cundity, and snail growth, fecundity, and feeding pref- erences over one growing season. Elevated [CO2] did not have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca have a signi®cant impact on (1) the combined biomass of fast-growing or slow-growing plants, (2) herbivore feeding preferences, or (3) herbivore ®tness. There was, however, a signi®cant biomass increase of Carex ¯acca (Helix aspersa