Two Decades of Experimental Manipulations of Heaths and Forest Understory in the Subarctic
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Current atmospheric warming due to increase of greenhouse gases will have severe consequences for the structure and functioning of arctic ecosystems with changes that, in turn, may feed back on the global-scale composition of the atmosphere. During more than two decades, environmental controls on biological and biogeochemical processes and possible atmospheric feedbacks have been intensely investigated at Abisko, Sweden, by long-term ecosystem manipulations. The research has addressed questions like environmental regulation of plant and microbial community structure and biomass, carbon and nutrient pools and element cycling, including exchange of greenhouse gases and volatile organic compounds, with focus on fundamental processes in the interface between plants, soil and root-associated and free-living soil microorganisms. The ultimate goal has been to infer from these multi-decadal experiments how subarctic and arctic ecosystems will respond to likely environmental changes in the future. Here we give an overview of some of the experiments and main results.
KeywordsTundra Warming Field experiments Plant–microbe interactions Carbon and nitrogen cycling
We are grateful to the staff at the Abisko Scientific Research Station for excellent facilities and support, and to the Director through many years, Prof. Terry V. Callaghan, for his encouragement and enthusiastic work in arctic ecological research. The studies have been supported by multiple grants from The Danish Council for Independent Research. We also wish to thank The Danish National Research Foundation for funding the activities within the Center for Permafrost (CENPERM). Numerous colleagues, students and field assistants are thanked for enthusiastic collaboration during the field and analytical work.
- Aerts, R., J.H.C. Cornelissen, and E. Dorrepaal. 2006. Plant performance in a warmer world: General responses of plants from cold, northern biomes and the importance of winter and spring events. Plant Ecology 182: 65–77.Google Scholar
- Arroniz-Crespo, M., M.D. Gwynn-Jones, T.V. Callaghan, E. Nunez-Olivera, J. Martınez-Abaigar, P. Horton, and G.K. Phoenix. 2011. Impacts of long-term enhanced UV-B radiation on bryophytes in two sub-Arctic heathland sites of contrasting water availability. Annals of Botany 108: 557–565.CrossRefGoogle Scholar
- Callaghan, T.V., L.O. Björn, Y. Chernov, T. Chapin, T.R. Christensen, B. Huntley, R.A. Ims, M. Johansson, et al. 2004. Effects on the function of Arctic ecosystems in the short- and long-term perspectives. AMBIO 33: 448–458.Google Scholar
- Christensen, T.R., T. Johansson, M. Olsrud, L. Ström, A. Lindroth, M. Mastepanov, N. Malmer, T. Friborg, et al. 2007. A catchment-scale carbon and greenhouse gas budget of a subarctic landscape. Philosophical Transactions of the Royal Society A-Mathematical Physical and Engineering Sciences 365: 1643–1656.CrossRefGoogle Scholar
- Craine, J.M., A.J. Elmore, M.P.M. Aidar, M. Bustamante, T.E. Dawson, E.A. Hobbie, A. Kahmen, M.C. Mack, et al. 2009. Global patterns of foliar nitrogen isotopes and their relationships with climate, mycorrhizal fungi, foliar nutrient concentrations, and nitrogen availability. New Phytologist 183: 980–992. doi: 10.1111/j.1469-8137.2009.02917.x.CrossRefGoogle Scholar
- Ekberg, A., A. Arneth, and T. Holst. 2011. Isoprene emission from Sphagnum species occupying different growth positions above the water table. Boreal Environment Research 16: 47–59.Google Scholar
- Faubert, P., P. Tiiva., A. Michelsen, Å. Rinnan, H. Ro-Poulsen, and R. Rinnan. 2012. The shift in plant species composition in a subarctic mountain birch forest floor due to climate change would modify the biogenic volatile organic compound emission profile. Plant and Soil 352: 199–215. doi: 10.1007/s11104-011-0989-2.
- Haugwitz, M.S., I.K. Schmidt, and A. Michelsen. 2011. Long-term microbial control of nutrient availability and plant biomass in a subarctic-alpine heath after addition of carbon, fertilizer and fungicide. Soil Biology & Biochemistry 43: 179–187. doi: 10.1016/j.soilbio.2010.09.032.CrossRefGoogle Scholar
- Jonasson, S., and A. Michelsen. 1996. Plant nutrition and nutrient cycling in the Subarctic, with special reference to the Abisko and Torneträsk area. Ecological Bulletins 45: 45–52.Google Scholar
- Karlsson G.P., C. Akselsson, S. Hellsten, P.E. Karlsson, and G. Malm. 2009. Övervakning av luftföroreningar norra Sverige – mätningar och moddellering. Svenska Miljöinstitut IVL rapport B1851. Lund Universitet (in Swedish).Google Scholar
- Michelsen, A., E. Graglia, I.K. Schmidt, S. Jonasson, C. Quarmby, and D. Sleep. 1999. Differential responses of grass and a dwarf shrub to long-term changes in soil microbial biomass C, N and P by factorial NPK fertilizer, fungicide and labile carbon addition to a heath. New Phytologist 143: 523–538.CrossRefGoogle Scholar
- Olsrud, M., B.Å. Carlsson, B.M. Svensson, A. Michelsen, and J.M. Melillo. 2010. Responses of fungal root colonization, plant cover and leaf nutrients to long-term exposure to elevated atmospheric CO2 and warming in a subarctic birch forest understory. Global Change Biology 16: 1820–1829. doi: 10.1111/j.1365-2486.2009.02079.x.CrossRefGoogle Scholar
- Rinnan, R., Å. Rinnan, P. Faubert, P. Tiiva, J.K. Holopainen, and A. Michelsen. 2011b. Few long-term effects of simulated climate change on volatile organic compound emissions and leaf chemistry of three subarctic dwarf shrubs. Environmental and Experimental Botany 72: 377–386.CrossRefGoogle Scholar
- Robinson, C.H., P.A. Wookey, A.N. Parsons, J.A. Potter, T.V. Callaghan, J.A. Lee, M.C. Press, and J.M. Welker. 1995. Responses of plant litter decomposition and nitrogen mineralisation to simulated environmental change in a high arctic polar semi-desert and a subarctic dwarf shrub heath. Oikos 74: 503–512.CrossRefGoogle Scholar
- Sorensen, P.L., A. Michelsen, and S. Jonasson. 2008a. Ecosystem partitioning of 15N-glycine after long-term climate manipulations, plant clipping and addition of labile carbon in a subarctic heath tundra. Soil Biology & Biochemistry 40: 2344–2350. doi: 10.1016/j.soilbio.2008.05.013.CrossRefGoogle Scholar
- van Wijk, M.T., K.E. Clemmensen, G.R. Shaver, M. Williams, T.V. Callaghan, F.S. Chapin III, J.H.C. Cornelissen, L. Gough, et al. 2004. Long-term ecosystem level experiments at Toolik Lake, Alaska, and at Abisko, Northern Sweden: Generalisations and differences in ecosystem and plant type responses to global change. Global Change Biology 10: 105–123.CrossRefGoogle Scholar