Fróðskaparrit - 01.01.2004, Blaðsíða 235

HÆDDARÚTBREIÐSLA AV PLANTUSAMFELØGUM í FØROYUM
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distribution is rather disjunct. It is also de-
scribed from the southern hemisphere in
Tierra del Fuego (Hulten and Fries, 1986).
The Festuca vivipara-Agrostis capilla-
ris community is common on steep slopes
with many species and low vegetation cov-
er. Hansen (1967) and Hobbs and Averis
(1991) have described similar communities
(see Fosaa, 2001 for an overview). This
community is similar to the Festuca ovina-
Agrostis capillaris-Alchemilla alpina com-
munity (Rodwell, 1992-1995) in Scotland.
The Bistorta vivipara-Festuca vivipara
community has species of high constancy
like Thalictrum alpinum, Silene acaulis
and Racomitriun lanuginosum. This com-
munity is similar to the British Festuca ovi-
na-Alchemilla alpina-Silene acaulis com-
munity, which is found in the high alpine
region of Scotland, seldom below 700 m
a.s.l. (Rodwell, 1991-1995), and in Iceland
in low alpine areas (Páhlsson, 1998). In
the Faroe Islands, a Bistorta vivipara-Raco-
mitrium lanuginosum community has been
described in the alpine vegetation zone
(Bocher, 1937).
The Deschampsia flexuosa-Rhytidiadel-
phus loreus community has constant species
such as Carex bigelowii, Agrostis capillaris
and Festuca rubra. This community is sim-
ilar to the British Carex bigelowii-Polytri-
chum alpinum sedge heath (Rodwell, 1991-
1995), although the British community is
not as rich in species such as Deschampsia
flexuosa and Rhytidiadelphus loreus. This
vegetation is found in high mountain ar-
eas with a long duration of snow cover in
Scotland, often on transects with north- or
east-facing aspects. The Deschampsia flex-
uosa-Anthoxanthum odoratum-Alchemilla
alpina community is distributed in the low
and middle alpine area across the whole of
Iceland, while it is restricted to the mid-
dle boreal area of Fennoscandia (Páhlsson,
1998). The Faroese version of this commu-
nity does not have any Anthoxanthum odo-
ratum, but is rich in Carex bigelowii and
Polytrichum spp. This community has not
been discussed in older literature from the
Faroe Islands.
Racomitrium vegetation is widespread
at all altitudes in the Faroe Islands. True
Racomitrium vegetation without too many
other species of high dominance, however,
is restricted to high altitudes and mountain
summits. An example is the Racomitrium
lanuginosum community. In oceanic North
Atlantic areas like Iceland (Gunlaugsdot-
tir, 1985), Scotland (McVean and Ratcliffe,
1962), and the Faroe Islands (Ostenfeld,
1905-1908; Bocher, 1940), Racomitrium
dominated communities often transition
gradually into grassy moors, grassy heath
land and dwarf shrub communities. This
kind of community is equivalent to the moist
heath and grassland vegetation classifíed
in this study. Racomitrium heath, which is
similar to the high mountain vegetation in
the oceanic North Atlantic, is found on arc-
tic islands like Jan Mayen and Bear Island,
but the lowland transition type of grassy
moor, grassy heath land, and dwarf shrub
heath are not found on these arctic islands
(Virtanen et al., 1997). The Racomitrium
lanuginosum community is similar to
the British Carex bigelowii-Racomitrium
lanuginosum community, found in high al-
pine snow bed areas in Scotland (Rodwell,