Fróðskaparrit - 01.01.1998, Blaðsíða 305

311
Could Plants survive glacial climatic
Conditions in Iceland? - Implications of the
Lake Torfadalsvatn Pollen Record
✓
Kundu plantur hóra undan í seinastu ístíð í Islandi?
- Ábendingar av flogsáðskrásetingum úr Torfadalsvatni
Mats Rundgren
Mats Rundgren, Department of Quaternary Geology, Lund University, Tomavagen 13, SE-223 63 Lund, Sweden
phone: +46-46-222 7889, fax: +46-46-222 4830, e-mail: mats.rundgren@geol.lu.se
Úrtak
Upplýsingar um flogsáð úr Norðuríslandi sýna, at floran
í tí yngra dryastíðarskeiðnum var lutfalsliga fjølbroytt.
Av tí at íslendska veðurlagið hetta tíðarskeið líktist veð-
urlagnum, tá ið tað var kaldast seinastu ístíð, og tá havt
verður í huga, hvussu lutfalsliga fjølbroytt plantulívið er
í háarktiskum økjum og nunatakum í dag, er tað sann-
líkt, at nøkur harðbalin sløg eisini hóraðu undan alla
seinastu ístíð í Islandi.
Extended abstract
Pollen assemblages preserved in lake sedi-
ments deposited during the Younger Dryas
stadial, a cold event during the last glacial-
interglacial transition, reflect the presence
of a relatively diverse flora on the Skagi
peninsula in northern Iceland, including
woody plants like Betula nana, Salix, and
possibly also Juniperus communis (Rund-
gren, 1995). This discovery has implica-
tions for the much-debated question of
plant survival in Iceland during glacial pe-
riods (e.g. Buckland and Dugmore, 1991),
since palaeoceanographic data suggest that
Younger Dryas climatic conditions in
northem Iceland were similar to those at
the peak of the last (Weichselian) glacial.
Summer sea-surface temperatures north of
Iceland were no more than 3°C lower dur-
ing the last glacial maximum than during
the Younger Dryas stadial (Sarnthein et al.,
1995), and estimates of winter sea-surface
temperatures are almost identical for both
periods. In addition, recent palaeoclimatic
data from ice-cores and deep-sea sediment
cores show that the Weichselian was a peri-
od of abrupt changes in air temperature and
ocean circulation in the North Atlantic re-
gion (Johnsen et al., 1995; Dokken and
Hald, 1996), with the coldest events of
about the same duration as the Younger
Dryas stadial.
Taking into account that many plants can
endure extreme climatic conditions, as
shown by the relative diversity found in
high Arctic areas (e.g. Edlund and Alt,
1989; Bay, 1992) and in present-day
Fróðskaparrit 46. bók 1998: 311-313