Full-text - Norsk entomologisk forening

228 A. Lillehammer
Fig. 22. Stream Byrkjelandselva at Sveio in the
coastal area (A).
nearly the same height above sea level (from
5 to 10 m). The streams were chosen to be
as similar as possible regarding size of substratum
and amount of vegetation along the
streams. In an attempt to eliminate differences
in results arising from differences in
stream size, small and large streams both in
coastal areas and in the fjord areas were
examined for comparison. In all streams,
areas with riffles and pools and with different
substrata were investigated. The
amount of allochthonous matter was similar,
although somewhat less in Nordelva than in
the other two streams. The dominant deciduous
trees were Alnus, but Salix and other
trees were also present. All three streams
were surrounded by cultivated land.
Physical and chemical data from the
streams are given in Table XIX.
Stonefly fauna
The same trends were found as during the
investigation of the total area (Table XX).
Leuctra digitata, Capnia pygmaea and /soperla
obscura were only taken in Nordelva
and in fact have not been taken west of the
inner fjords.
Fig. 23. Stream Sandeidelva at Sandeid in the
central area (B).
Table XVIII. Temperatures (0C) at three stations
in the horizontal distribution investigation
Station
Date I 2 3
28 Apr. 66 11 3 2
15 June 66 \5 14 7
22 March 67 5 1 1
28 May 67 12 - 4
10 July 67 16 12 6
3 Sept. 67 12.5 10.5 9
28 May 70 16 12 4.5
8 Apr. 71 7 3 4
-­
Mean \1.7 7.9 4.9
Fig. 24. Stream Nordelva at Sauda in the inner
fjord area (C). Station (I). in the vertical zonation,
and station (3) in the horizontal zonation.
in Sveio, Hordaland (Fig. 22); Sandeidelva in
Vindafjord (Fig. 23) and Nordelva in Sauda
(Fig. 24), both in Rogaland. They represented
the range from coastal areas with an atlantic
climate to inner fjord areas with a more
continental climate. All the stations were
Table XIX. Maximum and mIlllmum measurements
of pH, Ca++ hardness and Mg++ hardness
at three stations in the horizontal zonation
in area 1
pH Ca++ mg/l Mg++ mg/l
Stations Max Min Min Max Min Max
1 6.7 6.4 0.4 1.7 0.3 0.4
2 6.4 5.3 0.2 1.7 0.1 0.2
3 6.0 5.6 0.1 0.9 0.1 0.2