Fróðskaparrit - 01.01.1998, Page 306

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COULD PLANTS SURVIVE GLACIAL CLIMATIC CONDITIONS INICELAND?
- IMPLICATIONS OF THE LAKE TORFADALSVATN POLLEN RECORD
nunatak areas in Iceland and Greenland
(Einarsson, 1970; Gjærevoll and Ryvarden,
1977), plant survival in Iceland during
glacial climatic conditions may well be fea-
sible, given that ice-free areas existed.
There are strong geomorphological indica-
tions from several coastal mountain areas
for ice-free conditions during the last
glacial maximum (e.g. Sigurvinsson, 1983;
Hjort et al., 1985; Norðdahl, 1991), but
there are yet no palaebotanical data avail-
able from these areas to support glacial
plant presence.
The Icelandic fossil plant record reflects
a Late Cenozoic cooling and a transition
from a flora dominated by American ele-
ments to one with more European affinities
(Símonarson, 1979; Einarsson, 1994), and
many of the taxa important in the present
Icelandic flora, e.g. Betula nana, Salix, Em-
petrum nigrum, Ericaceae, Poaceae, Cyper-
aceae, Dryas octopetala, Caryophyllaceae,
Plantago and Lycopodium, are recorded al-
ready in the early Pleistocene. This floral
change may be interpreted as the result of
increased long-distance dispersal from
northwestern Europe and northem Eurasia,
due to a gradual change in oceanic circula-
tion in connection with the opening of the
North Atlantic, in combination with plant
survival in Iceland during cold periods and
glaciations. The lack of endemics in the
Icelandic flora may be explained by contin-
uous long-distance dispersal by ocean cur-
rents, wind and birds, both in the post-
glacial period and earlier epochs.
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