Full-text - Norsk entomologisk forening

Norwegian stone/lies II 219
which was also taken in the same habitats.
Diura nanseni and Arcynopteryx compacta
were also present. The most common herbivorous
species were N emoura cinerea and
Amphinemura borealis, which also occurred
in large numbers. Four of the five northern
species were taken in this area, N emoura
arctica, N emoura sahlbergi, N emoura viki
and Protonemura intricata.
The total number of species in area 7 is 28,
as Amphinemura norwegica, Leuctra /usca,
Cafmia vidua and Isoperla difformis were
registered by Tobias (1973, 1974).
Discussion: northern Norway
Of the areas investigated, Kautokeino and
Pasvik contained the richest fauna with 27
and 28 species, Alta and Korpfjell the poorest
with 18 and 15 species, respectively.
There are marked differences between the
areas. The three carnivorous species occupy
quite different positions. In Pasvik
Diura bicaudata completely dominated and
was numerous both in lakes, outlets and
streams while Diura nanseni and Arcynopteryx
compacta were rare. Around Kautokeino
Diura bicaudata still dominated, but
Diura nanseni and Arcynopteryx compacta
were more common and were taken in greater
numbers. Around Alta Arcynopteryx compacta
was more common than either Diura
bicaudata or Diura nanseni. In all three
areas Arcynopteryx compacta, Diura bicaudata
and Diura nanseni were taken at least
once together in lakes or outlets. Among the
omnivores, Isoperla obscura was common in
Pasvik and Kautokeino but not around Alta.
Among the herbivores, Leuctra hippopus,
Nemoura cinerea and Capnia atra were most
common in Alta. In Pasvik Amphinemura
borealis and N emoura cinerea were the most
common while in the Kautokeino area N e­
moura avicularis, N emoura cinerea, Leuctra
hippopus and Capnia atra were the most
common herbivorous species. Most marked
was the absence of the Amphinemura species
in the Alta area.
COMPARISON OF SOUTHERN AND
NORTHERN NORWAY
There were considerable differences in the
fauna distribution in the 7 areas investigated.
For the most part they hold different species.
Even the species which they have in common
vary in occurrence from area to area. The
differences between the north and south in
the distribution of the carnivore species Diura
nanseni, Diura bicaudata and Arcynopteryx
compacta are marked. In the north the three
species are very common and occur in small
and large streams, lakes and outlets, sometimes
occurring together. In the south, however,
they have a quite different distribution.
Diura bicaudata is found solely in lakes and
outlets and Diura nanseni is nearly always
taken in streams, both lowland and high
altitude. In the Low-Alpine belt and above,
Arcynopteryx compacta takes over as the
most common carnivorous species. The three
species were never taken together in the south.
The wider ecological preference of these
species in northern Norway indicates that
environmental conditions are neairer the
optimal.
Two other species, the herbivore Amphinemura
borealis and the omnivore Isoperla
obscura, also have a wider distribution in
the north and therefore also seem to be in
or near their optimal environment.
Both in the east and west of southern
Norway there is a reduction in the number
of species from inner fjords towards coastal
areas. In southern Norway the species of the
family Capniidae are mainly found in the
parts where there are rich soils with deciduous
trees along the streams. This is documented
both in areas 2 and 3.
Common for northern, southern and western
areas is the decrease in species where the
deciduous trees and willow bushes disappear
from along the streams at higher altitudes.
The fauna of the Sub-Alpine birch wood
areas is richer in the continental areas in
northern Norway and poorest in the western
areas in southern Norway. The differences
shown in the present work were so marked
that it seems natural to compare the results
with the results of other investigations made
in northern Fennoscandia by Brinck (1949),
Brinck & Wingstrand (1949), Brinck & Froehlich
(1960), Bagge (1965, 1968), Ulfstrand
(1967, 1968a & b, 1969), Ulfstrand et al.
(1971), Meinander (1972). They are all shown
to be different from the Norwegian areas and
from each other. The Kilpisjarvi area in
Finland (Meinander 1972) is situated at the