High Resilience in Heathland Plants to Changes in Temperature, Drought, and CO sub(2) in Combination: Results from the CLIMAITE Experiment

• Published in: Ecosystems (New York) 2012-03, Vol.15 (2), p.269-283
• Main Authors: Kongstad, Jane, Schmidt, Inger K, Riis-Nielsen, Torben, Arndal, Marie F, Mikkelsen, Teis N, Beier, Claus
• Format: Article
• Language: English
• Subjects: Calluna vulgaris; Deschampsia flexuosa
• ISSN: 1432-9840; 1435-0629
• DOI: 10.1007/s10021-011-9508-9

Climate change scenarios predict simultaneously increase in temperature, altered precipitation patterns and elevated atmospheric CO sub(2) concentration, which will affect key ecosystem processes and plant growth and species interactions. In a large-scale experiment, we investigated the effects of in situ exposure to elevated atmospheric CO sub(2) concentration, increased temperature and prolonged drought periods on the plant biomass in a dry heathland (Brandbjerg, Denmark). Results after 3 years showed that drought reduced the growth of the two dominant species Deschampsia flexuosa and Calluna vulgaris. However, both species recovered quickly after rewetting and the drought had no significant effect on annual aboveground biomass production. We did not observe any effects of increased temperature. Elevated CO sub(2) stimulated the biomass production for D. flexuosa in one out of three years but did not influence the standing biomass for either D. flexuosa or the ecosystem as more litter was produced. Treatment combinations showed little interactions on the measured parameters and in particular elevated CO sub(2) did not counterbalance the drought effect on plant growth, as we had anticipated. The plant community did not show any significant responses to the imposed climate changes and we conclude that the two heathland species, on a short time scale, will be relatively resistant to the changes in climatic conditions.