VEGETATION ECOLOGY ALONG A TROPHIC GRADIENT ON DRAINED PINE MIRES IN SOUTHERN FINLAND

The study treats the plant communities of sedge pine mires drained for forestry ca. 25 years previously (60 sites) an those of natural mires (10 sites) of the same site types. The plant communities were analysed in relation to the following environmental variables: the tree stand characteristics, hydrology and nutrient contents of the Peat. Canonical correspondence, analysis was used to relate the environmental variables to the plant community data. The species-environment relationships are also shown by means of scatter Plots. Because of the problem of multicollinearity, the effects of the individual environmental factors could not be studied in detail. It is evident, however, that the post-drainage vegetation succession has been most rapid in the mom fertile site types, due to the tree stand development and the higher nutrient levels. In fact, sites drained at about the same time, represent different stages of succession. The results show, however, that the post-drainage plant communities can be used in site classification. The distinction between the site classes is better in the nutrient-rich part of the tropic series.