Table IX. Species distribution in selected water courses and the number of specimens taken in the whole of area 7 (South Varanger) 'N 'Ṇ.. .::/ .::l ::>.. ~ ':l '::/ ;:l '" :::: ':l ':l "'- Cl " ':l 'N "t '" '" ~ ~ ,;: ~ ""- .;: ..2 ., ., ., ... t-< N. '" ;:l '" 'N ~ I:: ... ';::: ':l 'bi.J 'N I:: ... " ... oo
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
Change language