Ecological, topographic and successional patterns across wetlands in a rugged land uplift coast in Nyby, northern Finland

We studied 45 mid-boreal wetlandsin a rugged land uplift coast with a thin cover of till. Wetlandsranged from 1 to 53 m a.s.l. and were of highly various sizes. Our aims were to examine, if vegetation typesare valid in comparing wetlands, what kind of ecological major pattern the vegetation typecomposition of wetlandsshows and how vegetation typesdistribute across altitudes. On those ground we discuss the wetlandsuccession of the study area. We used the Finnish miresite types as vegetation types. Miresite types could be used for an ecological classification and ordination of the wetlands. As was expected, the major gradient consisted of the transition from miremargin (swamp) to expanse. The distribution of the Major Vegetational WetlandGroups (MVWG) responded to a general water-flow pattern in the landscape. Partly different peatland succession sequences occur in areas with small mirebasins and in areas with larger mirebasins with evolving mirecomplexes. Sequences of small wetlandsand those of mirecomplexes follow the same trajectory only as far as the major gradient is considered while they differ with regard to the vegetation typecomposition of locally rare vegetation typesand with regard to peatland morphology. Trajectories of mirecomplexes at catchment divides differfrom those at catchment centers where the waters in the landscape tend to gather. Peatland forms of aapa miresexperience a change reaching altitudes of 30–50 m a.s.l. Small bogcomplexes at catchment divides reach a stage of an unpatterned Sphagnum fuscum bogin the study area. Mature mixed complexes with aapa- mireparts and patterned sloping- bogparts only occur at altitudes higher than 60 m a.s.l. Peculiarities in the succession of the wetlandsof Nyby, which include the presence of separate incomplete successional sequences in the same area, are mainly caused by the peculiar topography with various sub-areas and with an abundance of rock outcrops.