A multi-proxy palaeoecological study of Alanen Laanijärvi, a boreal-forest lake in Swedish Lapland |
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| Authors: | MARKUS L HEINRICHS SYLVIA M PEGLAR CHRISTIAN BIGLER H JOHN B BIRKS |
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| Institution: | Markus L. Heinrichs (e-mail: ), Climate Impacts Research Centre, Box 62, SE-981 07 Abisko, Sweden;Department of Ecology and Environmental Science, UmeåUniversity, SE-901 87 Umeå, Sweden (current address: Department of Geography, Okanagan University College, 3333 University Way, Kelowna, British Columbia, V1V 1V7, Canada);Sylvia M. Peglar, Department of Biology, University of Bergen, NO-5007 Bergen, Norway;Christian Bigler, Climate Impacts Research Centre, Box 62, SE-981 07 Abisko, Sweden;Department of Ecology and Environmental Science, UmeåUniversity, SE-901 87 Umeå, Sweden;H. John B. Birks, Environmental Change Research Centre, University College London WC1H 0AP, UK;Department of Biology and Bjerknes Centre for Climate Research, University of Bergen, NO—5007 Bergen, Norway |
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| Abstract: | Heinrichs, M. L., Peglar, S. M., Bigler, C. & Birks, H. J. B. 2005 (May): A multi-proxy palaeoecological study of Alanen Laanijärvi, a boreal-forest lake in Swedish Lapland. Boreas , Vol. 34, pp. 192–206. Oslo. ISSN 0300–9483.
Chironomids, pollen and spores were used to reconstruct Holocene aquatic and terrestrial environments at Alanen Laanijärvi, northern Sweden. Chironomid analysis revealed a pattern of limnological evolution from oligotrophic conditions in a relatively deep lake during 8.6 to 5.5 cal. kaBP, followed by a period of lake shallowing from 5.5 to 2.7 cal. ka BP. Increases in acidity and littoral habitat complexity may have occurred from 2.7cal. kaBP to the present, though some compositional changes may have resulted from human disturbance. Chironomid-inferred mean July air temperatures range between 9.8C in the Early Holocene to 11.3C in the Late Holocene. Limitations on chironomid-based quantitative temperature interpretations may exist because of low taxon richness. Diatoms were recovered from the upper sediments only, from about AD 1800. Pollen and spore analysis revealed an early colonizing vegetation of juniper, sedges and birch soon after local deglaciation, followed by birch forests until about 8.3 cal. kaBP. Alder stands occurred locally to 5.5 cal. kaBP, when pine and spruce forests developed and remain to the present day. These results suggest that little major terrestrial vegetation change may occur in some northern environments with predicted future global warming, where it is predicted to be most severe. Aquatic environments may, however, be greatly affected by a shift in precipitation regime, causing changes in allochthonous organic input, lake depth and possibly the amount of human activity or disturbance in the watershed. |
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