Four millennia of rich fen vegetation composition and haymaking in boreal outfields at Nordmøre (Møre og Romsdal), Norway

Abstract This study provides new evidence on the beginning and continuity of outfield fen mowing, an essential practice to obtain fodder for the winter in traditional Norwegian farming. Pollen and spores from a peat sequence in a historically mown fen at Tågdalen (Nordmøre) were analysed and compared with modern vegetation and pollen data from local and regional reference sites using the modern analogue technique. A sloping rich fen developed from around 2350 bc from smaller patches, discontinuously expanding to its present-day extent around ad 980. Pollen of taxa which indicate mowing reveal the start and intensity of management for hay. Extensive mowing (about every 4 years) is detected from the early Roman Iron Age, ca. ad 40 onwards. Analogue matching indicates intensive mowing practices (about every 2 years) in a farming community in the early High Middle Ages, from ca. ad 1135. Mowing generally resulted in quantitative changes in fen plant cover, leading to an increased number of flowering plants and more pollen deposition of Thalictrum , probably T. alpinum , and Eriophorum spp. Mowing intensified in frequency and extent from ca. 1850, during the time of peak use of outfield resources in Norway, followed by a reduction from ca. 1920. Abandonment of mowing was reflected in the pollen composition from about 1940, in accordance with historical data. The fen represented an important resource under different cultural, social and climatic conditions. The main vegetation changes were related to changing land use and management. Analogue matching helped infer taxa that are poorly represented in pollen, such as Orchidaceae. Combined with taxa indicating mowing, this approach enabled reconstruction of vegetation history connected with this land use.