Publication Date

1997

Description

Growth responses to a doubling of the atmospheric CO2 concentration for 15 species represented in temperate pastures of southern Australia were investigated in a glasshouse experiment. The final dry weight increase due to CO2 enrichment averaged 34% across species but varied widely. The variation in CO2 response was greater among species within botanical groups than it was among groups. The CO2 response of a number of ‘desirable’, but also a number of ‘undesirable’ species was greater than the mean response, suggesting that these species may increase their proportion in pastures as atmospheric CO2 rises. Our results do not support the hypotheses that CO2 responsiveness is related to nutrient responsiveness or to the species inherent relative growth rates. Thus, knowledge of CO2 response at the level of the individual species may be necessary to understand, predict or model the response of plant communities to elevated CO2.

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Growth Response of Australian Temperate Pasture Species to CO2 Enrichment

Growth responses to a doubling of the atmospheric CO2 concentration for 15 species represented in temperate pastures of southern Australia were investigated in a glasshouse experiment. The final dry weight increase due to CO2 enrichment averaged 34% across species but varied widely. The variation in CO2 response was greater among species within botanical groups than it was among groups. The CO2 response of a number of ‘desirable’, but also a number of ‘undesirable’ species was greater than the mean response, suggesting that these species may increase their proportion in pastures as atmospheric CO2 rises. Our results do not support the hypotheses that CO2 responsiveness is related to nutrient responsiveness or to the species inherent relative growth rates. Thus, knowledge of CO2 response at the level of the individual species may be necessary to understand, predict or model the response of plant communities to elevated CO2.