Asrun Elmarsdottir¹, Borgthor Magnusson¹ and Ingibjörg S. Jonsdottir². ¹The Agricultural Research Institute, Reykjavik, Iceland ²Department of Evolutionary Botany, Gothenburg University, Gothenburg, Sweden

In 1996 an ITEX project was started at Audkuluheidi, NW Iceland at 490 m a.s.l. The main aim of the project is to follow changes in vegetation composition, species abundance and canopy height. The demography of Carex bigelowii, soil characteristics and temperature are also monitored at the site.

Ten hexagonal open top champers (OTCs) and equal number of control plots were placed within fenced area (ungrazed). Outside the fence (grazed by sheep) are ten control plots which can be used to follow vegetation changes caused by cessation of grazing. Measurements of vegetation composition and canopy height will be repeated in 1999. Temperature was monitored in control and OTC plots from May - September 1998.

The vegetation type in the area is dwarf-shrub heathland with Racomitrium lanuginosum, Cetraria islandica, Betula nana and Empetrum nigrum as dominants. In plots inside the fence 25 vascular plant, 5 moss and 9 lichen species were recorded. The average soil pH is 6,5, carbon and nitrogen content is 4,9% and 0,4% respectively and depth of the soil to the glacial till is 63 cm.

Decorana ordination was done on the initial vegetation data collected in 1996 and 1997. A separation was not found between OTC, control and grazed plots indicating homogeneity in the vegetation. The canopy height of shoots of Betula nana was tested for initial difference between treatments, a significant difference was not found between OTC and control plots. Repeated sampling and ordination analysis should reveal future vegetation changes and trends between treatments.