Myrar på Storön vid Norrbottenskusten

Detta är en avhandling från Umeå : Umeå universitet

Sammanfattning: ELVELAND, J. 1976. Coastal mires on the Storön peninsula, Norrbotten, N Sweden. Wahlenbergia 3. 274 pp. (map + 1 fig. in end pocket). Umeå.Vegetation, flora and habitat conditions of mires on and above the seashore have been studied in an eutrophic coastal area (Storön) in N Sweden. Here the rate of land uplift is almost 1 m per century and vegetational dynamics are rather intense in the younger mires, especially in the seashore fens recently "born from the sea" (primary mire formation).The mire vegetation is dealt with in three main groups: seashore fens, fens above the seashore and bog vegetation. The plant communities have been classified on a basis of their physiognomically dominant species. "Sphagnum fuscum islets" (often called "miniature raised bogs" or "miniature bogs") in the rich fens form the predominant type of bog vegetation. In the present paper the main emphasis has been laid on the rich fens above the seashore.Several vegetational gradients are dealt with, i. a. rich fen-poor fen, mire margin-mire expanse and the complex gradient mud-bottom/carpet/magnocaricetum/ lawn/hummock. Both small-scale and large-scale successions are discussed and a floristic list (vascular plants, bryophytes and lichens) with ecological annotations is presented.Extensive field measurements of pH and electrolytic conductivity of mire waters have been made. The pH, ash content, SÌO2r s r P#• C and N, total content and exchangeable fractions of Na, K, Mg, Ca, Mn and Fe have been determined at different depths for various kinds of peat. The chemistry of lagoon and lake sediments have also been studied. The vertical gradients shown by the chemical parameters are of special interest regarding the Sphagnum fuscum islets. The surface peats of the islets are "functionally ombrotrophic", while from a depth of ca. 30 cm and downwards the chemical characteristics are those of a rich fen peat.Historical and present-day mire utilization is discussed, especially hay-making and cattle grazing.