Náttúrufræðingurinn - 1964, Blaðsíða 30

76
NÁTT Ú RUF RÆÐINGURINN
Plinarsson has in a paper 1959 stated from geological investigations that in
the Eyjafjörður-district a goocl deal of the mountains were really icefree during
the maximal glaciation of thc Great Ice Age. These mountains arc marked on
thc map (Fig. 1), ancl I have grouped them and marked them with the figures
1-23.
The Eyjafjörður-district is better investigated botanically tlian any other
district of Iceland, so that we know the total distribution of the plants within
the district comparatively well. In the district 77 centric species are found,
whereof 27 species are true alpine plants. Of these species 17 are so distinctly
connected with the icefree areas that of their 179 localities mentioned, 160
are in the icefree areas and the 19 localities then left are mostly in their
immediate vicinity, but 8 localities are in a mountain-group, where there might
have been nunataks. And outside the icefree areas most of these species are
hardly to be found. The remaining 10 alpine species are either common in
most of the mountains of the district or the knowledge of their distribution
is too uncertain to form a basis for conclusions. Yet they seem to be more
closely connected with the icefree areas than with other parts of the district.
The centric lowland species are 42. I divide them into four groups. 1) Species
which have a scattered distribution. These are 27 and are found in 184 local-
ities, whereof 135 are in close connection with the icefree areas, i. e. situated
in the slopes below the icefree mountaintops. Eighteen localities are in the
northern part of the district on the westside of the fjord, where Einarsson says
there has been a number of nunataks, although they are not marked on the
map. Only 11 of the localities left are situated in those parts of the districts
that are farthest from the icefree areas.
2) Five species common in the northern part of the district but not found
in the southern part. Their distribution may be caused by the climate which
is more marine in that part ol' the district. But on the whole the lowland
species are far more common in the northern part of the district, where the
icefree areas has been biggest and come closest to the sea level.
3) Three species witli conlinuous distribution in the central part of the
district, in close connection with the areas 8, 16—17, 20—21 and also area 1,
but not found elsewhere in the district.
4) Four species, where distribution leads to no conclusion.
As the figures show, the connection between the distribution of the centric
species in the Eyjafjörður-district and the icefree areas is so distinct that it can
hardly be a mere accident. It is also remarkable that hardly any of the centric
species are found in the widcst lowland area which had no icefree mountains
behind it, i. e. the inner part of the eastcoast of the fjord. The same applies
to the southern part of the district, where no nunataks liave been recorded.
In other words: The distribution of the centric species in the Eyjafjörður-
district points distinctly to their overwintering in icefree refugees in the
mountains during the Great Ice Age.
II. This part is some remarks and answers to Sturla Friðrikssons criticism of
the overwinteringstheory (Friðriksson 1962).