Phytosociological aspects of Dryas integrifolia vegetation on moist-wet soil in Northwest Greenland
Lünterbusch, Christoph H.; Daniëls, Fred J.A.
This paper deals with the results of a phytosociological study according to the Braun-Blanquet approach of Dryas integrifolia vegetation on moist-wet soil in the Uummannaq District, Northwest Greenland. Soil chemical analyses comprise pH, conductivity, C/N-ratio and content of organic material, Ca 2+ , Mg 2+ , K + , Na + and phosphate (mg/100g soil). Based on 49 relevés two associations and one community are distinguished, which were firstly described from the east coast of Greenland and so far only known from East Greenland. The Rhododendro-Vaccinietum microphylli Daniëls 1982 occurs on moist soil. A subass. campylietosum stellati nov. occurs mainly along lakes and rivulets and a subass. sphaerophoretosum globosi nov. is restricted to moist soil which dries out in summer. A north-western vicariant of the Saxifrago-Kobresietum simpliciusculae Daniëls & Fredskild in Fredskild 1998 mainly occurs on wet soil. A subass. ochrolechietosum frigidae nov. occurs on soil which partly dries out in summer and a subass. eriophoretosum angustifolii nov. occurs on permanent wet soil. An Eriophorum angustifolium-Rhododendron lapponicum community is confined to wet calcium- and magnesium-rich soil with permanent water supply. Literature research shows, that all vegetation types can be considered widespread in most parts of Greenland. Multivariate analyses (DECORANA and CANOCO) confirm the vegetation typology and the decisive differential role of soil moisture conditions between the vegetation types, just as do the results of a transect study along a soil moisture gradient. The vegetation types are classified within a new hygrophytic-mesophytic Rhododendrenion lapponici suballiance of the alliance Dryadion integrifoliae Ohba ex Danie¨ls 1982, order Kobresio-Dryadetalia (Br.-Bl. 1948) Ohba 1974, class Carici-Kobresietea Ohba 1974. The synecological conception of the Dryadion integrifoliae and floristical differentiation against Caricion atrofusco-saxatilis vegetation (Caricetalia davallianae Br.-Bl. 1949, Scheuchzerio-Caricetea (Nordh. 1937) R. Tx. 1943) are reconsidered and stated more precisely. The high species richness of Rhododendro-Vaccinietum vegetation stands with a mean species number of 65 and 70 per plot of respectively 4 m2 and 0.16 m2 is discussed.