The concepts mire-margin effect and mire-expanse effect have central positions in the ecology and classification of boreal mires in Finland. Spruce-hardwood swamp vegetation is distinctive for margin influenced sites, and bog/fen vegetation for the centre influenced ones. Mire-margin vegetation typically forms a gradient between upland vegetation proper and mire-centre vegetation; passing from paludified upland forests, through paludified mire-margin forests to spruce-hardwood swamps. As being mixtures or mosaics of several ecological guilds (forest, swamp, marsh and spring vegetation) the mire-margin communities have their own typical pattern of diversity.
The aim of the study was: 1. to explore the ecological structure in the vegetation of natural forested mire-margin communities using numerical ordination (DCA, Detrended Correspondence Analysis) and classification (TWINSPAN) techniques, 2. to inspect both alpha diversity (diversity indices and the number of species) and beta diversity (DCA) of the vegetation of mire-margin communities and 3. to compare the structural diversity of the natural forested mire-margin sites and managed upland forest sites by means of preliminary indices based on the dimensions of tree and shrub cover.
In this poster we present the results of the study based on the data collected in association with the establishment of special permanent plots in the 8th Finnish National Forest Inventory (198586). The study data consists of 92 plots of natural forested mire-margin sites in south and central Finland (6066°N) and a sample of managed upland forest sites from the same area.
Key words: boreal mire, boreal forest, alpha diversity, beta diversity.
Correspondence: Leila Korpela, Finnish Forest Research Institute, P.O. Box 18, FIN-01301 Vantaa, Finland
Telefax: +358-0-85705569
E-mail: leila.korpela@metla.fi