Fróðskaparrit - 01.01.2004, Síða 221

HÆDDARÚTBREIÐSLA AV PLANTUSAMFELØGUM í FØROYUM
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vegetation changes, based on plant com-
munities, along these altitudinal transects
in the Faroe Islands in order to define the
boundary between temperate vegetation in
the lowlands (temperate zone) and arctic-
alpine vegetation in the highlands (low al-
pine and alpine zones), and, in addition, to
further use these data as a basis for studying
the effect of changes in climate and land use
in the Faroe Islands. To place the vegetation
in the Faroe Islands in a broader context,
the plant communities are also discussed in
relation to plant communities in other simi-
lar oceanic areas.
Material and methods
Study cirea
The treeless Faroe Islands is usually placed
in the temperate vegetation zone in the low-
lands and into the arctic vegetation zone
in the highlands (Ostenfeld, 1905-1908;
Bocher, 1937). The highly oceanic climate
in the Faroe Islands, with an annual mean
temperature of 7°C and an annual mean
precipitation of 1,500 mm (lowlands),
yields measurable precipitation on 75% of
the days in a year (Cappelen and Laursen,
1998). The climate is greatly influenced by
the North Atlantic Current and by proxim-
ity to the common track of atmospheric
low-pressure systems in the North Atlantic
region. Consequently, the climate can be
humid, variable, and windy. Using the eco-
climatic-phytogeographical system, Tuh-
kanen (1987) included the Faroe Islands in
the highly oceanic sector of the hemiborial
sub-zone.
Grazing has a profound impact on
Fig. 1. Location ofthe Faroe Islands and location of
tliefive studied mountains in the Faroe Islands:
I: Sornfelli; 2: Mosarøkur; 3: Ørvisfelli; 4: Gráfelli
and 5: Villingardalsfjall.
the vegetation in the area. Sheep are the
most important herbivore, with an aver-
age number of around 44 sheep/km2 (Thor-
steinsson, 2001). The impact of geese and
hares, however, cannot be ignored, and, in
addition, there are larger herbivores like
cows and horses.
The soil in the Faroe lslands is relative-
ly nutrient poor (Olsen and Fosaa, 2002;