Main content area

Central boreal mire plant communities along soil nutrient potential and water content gradients

Närhi, Paavo, Middleton, Maarit, Hyvönen, Eija, Piekkari, Matti, Sutinen, Raimo
Plant and soil 2010 v.331 no.1-2 pp. 257-264
Carex, Comarum palustre, Equisetum fluviatile, Menyanthes trifoliata, cluster analysis, electrical conductivity, forestry, fuel production, indicator species, loess, peatlands, plant communities, regression analysis, soil, soil nutrients, species diversity, vegetation, water content, Finland, Lapland
Peatlands have traditionally been exploited in forestry and agriculture over the boreal region, yet they also provide substantial source of fuel production. The large-scale exploitation of peatlands has raised a concern about the diversity of mire plant communities. We studied composition of mire plant communities along soil nutrient potential and water content gradients, to recognize the areas with the high plant diversity. Soil electrical conductivity (ECb) was measured to characterise soil nutrient regimes and soil dielectric permittivity (DP) the soil (volumetric) water regimes. A total of 115 mire sites were studied in the central boreal region of south-western Finnish Lapland. We found that Ward's hierarchical cluster analysis produced eight stable ECb and DP clusters with discrete vegetation compositions. On the basis of a locally weighted regression analysis (Loess), Carex dioica L., Comarum palustre L., Equisetum fluviatile L., Menyanthes trifoliata L., and Scorpidium scorpioides (Hedw.) Limpr. were found as indicator species for nutrient-rich regimes as designated by high soil ECb. The soil ECb is a diagnostic measure of plant diversity as ECb > 7 mSm⁻¹ resulted in a considerable increase in species richness. Our classification method, based on electrical measurements, provides a simple way to classify mires and focus detailed research to areas with potentially high conservation value.