Holocene vegetation dynamics and inferred climate changes at Svanåvatnet, Mo i Rana, northern Norway

• Published in: Boreas
• Main Authors: BJUNE, ANNE E., BIRKS, H. J. B.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2007
• Subjects: Mo i Rana; Norway; Northern Norway
• Online Access: http://dx.doi.org/10.1111/j.1502-3885.2007.00006.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1502-3885.2007.00006.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1502-3885.2007.00006.x

Pollen and plant macrofossil analyses from Svanåvatnet in northern Norway provide records of past vegetation and climate in this region from c . 8700 cal. yr BP until the present. Pollen accumulation rates and the presence of plant macrofossils indicate that Betula pubescens (birch) was present from c . 8600 cal. yr BP and Pinus sylvestris (pine) from c . 8200 cal. yr BP. Quantitative climate is reconstructed using modern pollen‐climate transfer functions based on weighted‐averaging partial least squares regression. A rapid increase in mean July temperature (T jul ) and mean annual precipitation (P ann ) is inferred for the early Holocene. At times when tree abundance is at its highest and most diverse, inferred T jul indicates maximum temperatures during the mid‐Holocene of about 2°C warmer than at present. During the same time period, inferred P ann is 200–300 mm above present‐day conditions until c . 3000 cal. yr BP. Mean January temperatures (T jan ) are reconstructed to be about 2°C warmer than today from 8000 to 3500 cal. yr BP. After 3500 cal. yr BP until today, a gradual decrease is seen in all the reconstructed climate parameters, together with a reduction in tree abundance and the development of a mosaic of open vegetation with grasses, dwarf shrubs and wet areas, and of woodland containing B. pubescens , P. sylvestris and Picea abies (spruce).