fulltext - DiVA

to the Myrica- Cyperaceae fen in ALMQUIST (1929,Table 30), which is a type of rich fen veget2,tion.The south-western dwarf shrub heaths 129ERICA TETRALIX COMMUNITY.-This communityis rare in Sweden and nearly confined to the WestCoast (cf. BocHER 1943, p. 85). Erica tetralix is thechief dominant. Further Calluna vulgaris, Myricagale, Drosera rotundifolia, Carex panicea, Juncussquan·osus and Trichophorum caespitosum occur. Inthe bottom layer lichens are important (Cladoniacrispata, C. floerkeana, C. impexa, C. squamosa, C.uncialis, Cetraria islandica, Oornicularia aculeata).They are associated with the mosses Dicranumscoparium, Hypnum ericetorum, H. imponens andLeucobryum glaucum, as well as Ptilidium ciliareand several other liverworts. Peat-mosses (esp.Sphagnum compactum and S. molle) are found invarying amounts. Related communities occur on thebogs of the western type (cf. OsvALD 1923, pp.95 ff) and are widely distributed in western Europe ·(cf., e.g., V ANDEN BERGHEN 1951).SKANOR's LJUNG.-The largest area mainlycovered by Erica-Myrica vegetation is Skanor'sLjung on a low south-western peninsula projectingfrom Skane (GuNVOR RASMUSSON, unpubl.). Fora long time this area has been used for grazing andcutting of peat. The flat sandy soil is only slightlybrownish but covered by a peaty mor layer, whichimpedes the drainage. Its thickness is very variable(2 to 48 cm) but usually about 10 cm. The reactionis acid (pH 4.0-5.0).On some low ridges of sand there is a Calluna­Empetrum community, but most of the rest is heldby the Erica-Myrica vegetation. A lichen dominatedErica tetralix community occurs in areassituated above the highest winter water-level. Itprobably grows on soil exposed by peat cutting anddevelops into a Calluna dominated_ communityrich in Erica tetralix and Hylocomium splendens(cf. DAMMAN 1957, p. 381; GIMINGHAM 1961, Table7 and p. 675). Very large areas have the Myricagale-Molinia coerulea community and are submergedfor a long time each winter but not in anormal summer. Mter peat has· been cut the initialstages leading to this community seem to be EricaFig. 5. The shore of the oligotrophic lake Attavarasjon,Breared, SE Halland. In the background planted pineforest with some birch on a former Oalluna heath. In theuppermost zone of the geolittoral a Myrica gale - Moliniacoerulea community with Erica tetralix, Gentiana pneumonanthe,Potentilla erecta, Viola palustris, Juncus squarmsusand T'richophorum caespitosum. In the bottom layerSphagnum imbricatum and S. papillosum dominate. Ata somewhat lower level a Rhynchospora community, withDrosera intermedia, Lycopodium inundatum, Oarex Oederi,Rhynchospora alba, R. jusca, Sphagnum auriculatum, S.compactum and S. molle. Further lakewards, in the foreground,Littorella unijlora, Lobelia dortmanna and Ranunculusjlammula v. reptans. The lower limit of foliaceouslichens on the boulder marks high waters. Photo N.Malmer.tetralix communities rich in peat-mosses, esp.Sphagnum compactum. ·In such depressions (often caused by peatcutting) which are periodically submerged evenin summer, a Rhynchospora community replaces theother two. It cannot be regarded as a heath community,however. Its most typical species are Droseraintermedia, Hydrocotyle vulgaris, Lycopodium inundatum,Carex Oederi, C. panicea, Deschampsiasetacea (rare), Juncus bulbosus, Molinia coerulea,Pilularia globulifera (rare), Rhynchospora alba, R.fusca and in the sparse bottom layer Drepanocladusexannulatus, Scorpidium scorpioides (only locally),Sphagnum auriculatum and Gymnocolea inflata. Itdevelops into a Carex panicea - Molinia coeruleaActa Phytogeog.t·. Suec. 50