Full-text - Norsk entomologisk forening

Norwegian stone/lies II 213
NORTHERN NORWAY
The northern areas of Norway support a
special fauna (Table I). Studies making it
possible to compare the fauna of these areas
with those of southern Norway were preferable,
but the long travelling distance presented
problems. Therefore, the research could
not be of the same intensity as in the south,
and the areas were investigated only once
a year. The area around Kautokeino and the
coastal areas were visited both in 1968 and
1972 while the Pasvik area was visited only
in 1'966. The comparisons may, therefore,
not be so valid as in the south. Nevertheless,
the studies were carried out in the latter part
of June and July, the best months for Plecopteran
investigations in these areas, wh:re
the snow and ice disappears during the fIrSt
part of June.
Area 5. Kautokeino
This area was chosen because it lies within
the most continental area of Norway.
Area description
The area (Fig. 4) is part of the large
Kautokeino rural district which covers much
of inner Finnmark. It consists mostly of a
plateau cut into by river valleys. In this
area, 16 streams and 8 lakes were investigated.
The bedrock is Pre-Eocambrian which in
the far north changes to Eocambrian sediments.
The whole area is covered by a thick
layer of drift material, notably along the
Kautokeino river (Sollid et al. 1973).
Precipitation is less than 400 mm a year.
In Kautokeino village the valley floor lies at
3-400 m a.s.l. and the surroundings seldom
reach over 600 m a.s.l. In the north-western
areas the landscape is somewhat higher with
heights of 700 m a.s.l. and above. The area
is situated in the Sub-Alpine birch belt and
the Alpine belts.
In the valleys there is often very dense
growth of birch and willow, above which
there is a belt of willow, which may be very
dense in the lower parts.
Stream descriptions
The landscape is rich in lakes and streams,
most of them running into the Kautokeino
River, a part of the Alta watercourse. Both
small and large streams were investigated.
The pH was fairly constant at the time of
measurement, from 6.6 to 7.0. The Ca++
content varied quite a lot, from 0.83 to 28.7
mg/l. The highest values were recorded. in
small streams coming from shallow lakes With
slow renewal.
Stonefly fauna
During this investigation 26 species were
taken (Table VII). However, the total number
is 27, as Dinocras cephalotes was taken
in the Anojokka area in 1969. The five species
taken solely in northern Norway are
Capnia vidua, N emoura arctica, N emoura
sahlbergi, N emoura viki and Protonemura
intricata. The last mentioned is the only one
which has not been taken in this area, there
being only two records of this species, both
further north.
All the 27 species were taken in streams,
while in lakes and lakes outlets there were
10 species in each. In this area Diura bicaudata
was common both in streams and
lakes and dominated among the carnivorous
stoneflies. Diura nanseni was widespread
in both lakes and streams, but was
never as numerous as Diura bicaudata. The
third of the large carnivores, Arcynopteryx
compacta, was only found in lake outlets
and streams. All three occurred together in
the outlet of Stuorajavrre and in Masijokka.
The most common omnivorous species was
Isoperla obscura, which was taken in lakes,
outlets and streams.
Among the herbivorous species Leuctra
hippopus and Capnia atra were the most
widespread species, followed by N emoura
avicularis and N emoura cinerea.
In the streams the most common were
Leuctra hippopus, Capnopsis schilleri, Capnia
atra, Leuctra nigra and N emoura cinerea.
In certain streams N emoura arctica, N emoura
sahlbergi and N emoura viki were very numerous.
All the Norwegian N emoura species
have in fact been taken in streams in this
area. In lakes, four of them, N emoura avicularis,
N emoura arctica, N emoura cinerea
and N emoura viki, were taken.
Area G. Alta and its surroundings
This area (Fig. 4) represents the fjord areas
14 - Norsk ent. Tidsskr.