Fróðskaparrit - 01.01.1998, Blaðsíða 299

305
Environmental Change in ice-free
Greenland: a Review
Umhvørvisbroyting í tí ísfría Grønlandi: eitt yvirlit
01e Bennike
Geological Survey of Denmark and Greenland, Thoravej 8, DK-2400 Copenhagen, Denmark
Phone: +45 38 14 20 00, fax: +45 38 14 20 50, e-mail: obe@geus.dk
Úrtak
Lítil kunnleiki er um ikki-havbiotur fyri seinastu av-
glasialisering, men fyri 2,5 milliónum árum síðan var í
Norðurgrønlandi skógartundra við smáum trøum, og tað
bendir á ein miðaltemperatur um summarið, ið var 7-8
°C hægri enn í dag. I seinasta millumístíðarskeiði, fyri
um 115-130.000 árum síðan, var kjarr- og lynggróður í
Eysturgrønlandi, ið bendir á ein miðaltemperatur um
summarið, sum er um 5 °C hægri enn í dag. Tá ið temp-
eratururin var lægstur seinastu ístíð, var tað so kalt, at
bert sera harðførar plantur og sera harðbalin dýr komu
undan við lívinum í Grønlandi. Eftir seinastu avglasial-
isering, sum byrjaði fyri 11.600 árum síðan, fór ein slóð-
brótandi gróður uttan viðarplantur at breiða seg út yvir
landið. Temperatururin var helst hægstur longu tíðliga í
tí eftirglasiala tíðarskeiðnum, men nógvar plantur, nógv
dýr, og menniskjað, komu til Grønlands, eftir at temp-
eratururin var farin at lækka.
Abstract
Little is known about non-marine biotas prior to the last
deglaciation, but at 2.5 million years ago, forest-tundra
with small trees indicating a mean summer temperature
7-8°C higher than today existed in North Greenland.
During the last interglacial stage, at c. 115-130,000
years ago, scrub and healt vegetation in East Greenland
indicates a mean summer temperature c. 5°C higher than
today. During the temperature minimum of the last ice
age, temperatures were so low that only very hard plants
and animals could survive in Greenland. After the last
deglaciation that began at 11,500 years ago, a pioneer
vegetation without woody plants began to cover the
land. Temperatures probably already peaked in the ear-
ly part of the postglacial, but many plants and animals,
including man, immigrated to Greenland after tempera-
tures had begun to decline.
The ice-free parts of Greenland cover
around 380,000 km2, corresponding to 20%
of the total area of the island. Most parts are
mountainous, but major areas of lowlands
are found in some regions. Small patches of
subarctic birch woodland are found in the
far south where the mean July temperature
exceeds 10°C. In the far north, polar desert
with no woody plants, and a mean July
temperature of 0-2°C, is found in coastal
areas. Between these extremes, scrub and
healt vegetation is widespread in the low-
lands.
This small review focuses on non-marine
biotic changes during the Quarternary. The
main proxies for reconstructions of region-
al terrestrial biotic changes are pollen and
plant macrofossil analyses, which have
been applied in many parts of Greenland. In
addition, information is available from in-
sects, other invertebrates, and vertebrates.
Palaeolimnological studies have been per-
formed using macrofossils, diatoms and
Cladocera. Palaeo-environmental studies
of near-shore marine waters is primarily
based on molluscs.
At the beginning of the Quartemary, a
mixture of arctic and boreal plants com-
prising Dryas octopetala, Oxyria digyna,
Fróðskaparrit 46. bók 1998: 305-309