Regional and vegetation-ecological patterns in northern boreal flark fens of Finnish Lapland: analysis from a classic material

We analysed and interpreted ecologically a part of classic peatland vegetation material of prof. Rauno Ruuhijarvi dating from 1960. Sample plots formed a compositional gradient along NMDS 1 across three traditionally recognized peatland subzones of Finnish Lapland, and Cajanderian site types showed a poor-rich gradient along NMDS 2. Analysis-based major vegetation groups were related to the regional and the mire-expanse-to-margin gradient. Southerly-focused Eriophorum gracile-Potentilla palustris-Straminergon stramineum major group was interpreted as an indication of a more voluminous spring flood in a more oceanic climate, while northerly-focused Carex rotundata-Trichophorum cespitosum m. g. was interpreted as a reflection of a minor spring flood in a more continental climate. Regional communities were compatible with Cajanderian site types and showed new regional and vegetation-ecological features for site types. They were related to three European fen alliances, which represented boreal (Stygio-Caricion limosae), arcto-boreal-alpine (Drepanocladion exannulati) and widespread (Scheuchzerion palustris) vegetation. Introduction Mires in treeless fjelds belong to the least studied peatland types in Finland. Such sites are scattered and very small in area; they are more numerous in Sweden and Norway, which host the mountain range of the Scandes (Moen 1999, Rydin et al. 1999). Finnish Lapland, here referred to as an area roughly north of the Arctic