A Race for Space? How Sphagnum fuscum stabilizes vegetation composition during long-term climate manipulations

• Published in: Global Change Biology
• Main Authors: Keuper, Frida, Dorrepaal, Ellen, Van Bodegom, Peter M, Aerts, Rien, Van Logtestijn, Richard, Callaghan, Terry V, Cornelissen, Johannes HC
• Other Authors: Department of Systems Ecology, University of Amsterdam Amsterdam (UvA), Climate Impacts Research Centre (CIRC), Umeå University, Dept of Systems Ecology, Department of Animal and Plant Sciences, Sheffield Centre for Arctic Ecology, University of Sheffield, Abisko Naturvetenskapliga Station, Royal Swedish Academy of Sciences
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2011
• Subjects: Life Sciences; Arctic; Betula nana; Climate change; Subarctic
• Online Access: https://hal.archives-ouvertes.fr/hal-00609003; https://hal.archives-ouvertes.fr/hal-00609003/document; https://hal.archives-ouvertes.fr/hal-00609003/file/PEER_stage2_10.1111%252Fj.1365-2486.2010.02377.x.pdf; https://doi.org/10.1111/j.1365-2486.2010.02377.x

International audience Strong climate warming is predicted at higher latitudes this century, with potentially major consequences for productivity and carbon sequestration. Although northern peatlands contain one-third of the world's soil organic carbon, little is known about the long-term responses to experimental climate manipulations of vascular plant communities in these Sphagnum-dominated ecosystems. We aimed to see how long-term experimental climate change in and outside the growing season affects total vascular plant abundance and species composition when the community is dominated by mosses. During 8 years, we investigated how the vascular plant community of a Sphagnum fuscum-dominated subarctic peat bog responded to six experimental climate scenarios, including factorial combinations of summer as well as spring warming and a thicker snow cover. Vascular plant species composition in our peat bog was more stable than is typically observed in (sub)arctic experiments: neither changes in total vascular plant abundance, nor in individual species abundances, Shannon's diversity or evenness were found in response to the climate manipulations. For three key species (Empetrum hermaphroditum, Betula nana and S. fuscum) we also measured whether the treatments had a sustained effect on plant length growth responses and how these responses interacted. Contrasting with the stability at the community level, both key shrubs and the peatmoss showed sustained positive growth responses at the plant level to the climate treatments. However, a higher percentage of overgrown E. hermaphroditum shoots and a lack of change in B. nana net shrub height indicated encroachment by S. fuscum, resulting in long-term stability of the vascular community composition: in a warmer world, vascular species of subarctic peat bogs appear to just keep pace with growing Sphagnum in their race for space. Our findings contribute to general ecological theory by demonstrating that community resistance to environmental changes does not necessarily ...