Fróðskaparrit - 01.01.1992, Blaðsíða 58

62
THE LICHENS OF THE FAROES
area is 1399 km2. The islands are formed of
lavas about 50-60 mill. years old. The relief
is steep, the highest peaks reaching about
800 m a.s.l.
The climate is cold oceanic with month-
ly mean temperatures of 11 °C in August
and 4°C in February, and with a record
maximum of almost 25°C. The precipita-
tion amounts to 1200-2700 mm annually,
or even more in the mountains, mostly as
rain. Snow storms occur during winter, but
a snow cover of a longer duration is found
only in the mountains. Fog is very com-
mon, especially in summer.
The islands were perhaps totally covered
by ice during the last glaciation. Nunataks
may have been present on the highest parts
of the northem islands, but this has not
been proved. All life forms, or at least the
majority of species, must therefore have
invaded the area in postglacial time. The
recent introduction of some epiphytic
lichens and of Xanthoria elegans to the
islands was discussed by Alstrup & Alstmp
(10). Some genera are well represented and
therefore supposed to spread easily. In con-
trast Acarospora, Umbilicaria and Cetr-
aria e. g. are represented by only four, two
and one species respectively. Common and
widely distributed northern species as
Brodoa intestiniformis, Lecidoma demis-
sum, Orphniospora moriopsis, Diplo-
schistes scruposus and Icmadophila erice-
torum have not been found in the area.
The vegetation is superficially tundra-
like, but according to Tuhkanen (57) it is a
highly oceanic sector of the hemiboreal
subzone with the alpine areas above 150 m
belonging to the orohemiarctic zone.
The Faroes have been inhabited for
almost 1.500 years, the present population
amounts to c. 50.000 inhabitants. The econ-
omy is almost totally dependant on fishery
and whaling; sheep-breeding is also impor-
tant. (The indeginous name of the country
“Føroyar” means Sheep Islands). In prehis-
toric time the islands probably had a low
forest or scrub of birch and willow, with
juniper in some places. Due to the sheep-
breeding the scmb vegetation has almost
disappeared, and the present vegetation is
dominated by grasses and herbs, except for
a few plantations of recent age. Rocks are
totally covered in lichens and mosses.
Lichens are also found on soil, moss, turf,
building materials, bones etc.
The macrolichens of the Faroes are
presently not well-developed in most
places due to sheep-browsing. Sheep eat
lichens rather indiscriminately, and they are
good climbers. Good stands of macro-
lichens are therefor found only on steep
cliffs and huge blocks where sheep cannot
go. These places are also rather inaccessi-
ble to lichenologists. Collections of some
species of Lobaria, Sticta, Bryoria,
Parmelia s.l. and Platismatia are therefore
rare in the herbaria, but the species proba-
bly still exist in such protected places. Soil-
inhabiting lichens also suffer from tram-
pling of the sheep (with the exception of
Gyalecta foveolaris) and from a dense
grasscover, but the epilithic microlichens
are well-developed. During the last century
small plantations have been established in
many places. The plantations are fenced to
keep the animals out, and macrolichens
thrive well (10).