Skógræktarritið - 15.05.2001, Page 165

SKÓGRÆKT HANDAN SKÓGARMARKA / NSSE
ANDERS BRYN, ANN NORDERHAUG,
AND KAROLINE DAUGSTAD
Re-growth effects on vascular
plant richness in Norwegian,
abandoned summer farm areas
SAMANTEKT
Svæði á mörkum fjalllendis og Iáglendis eru mikiivæg fyrir afkomu
landbúnaðarvistkerfa á Norðurlöndum með því að veita bændum og
búfé þeirra líffræðileg gæði. í þessari rannsókn á sumarbýlaþyrping-
um á mörkum fjalllendis og Iáglendis sem eiga 4-5000 ára landnýt-
ingarsögu var könnuð tegundafjölbreytni háplantna eftir að býlin
höfðu verið yfirgefin. Þrjú framvindusvæði voru skilgreind, kortlögð
með GIS og notuð sem einingar í grasafræðilegar kannanir. Það kom í
Ijós að skráð áhrif endurvaxtar á fjölbreytileika plantna voru háð því
hvaða rúmlægi kvarði var notaður, og að tegundafjölbreytni plantna
jókst yfir lengra tímabil. Þegar endurvöxtur landslags á sumarbýlum
heldur áfram, rýrnar bæði líffræðilegt og menningarlegt gildi þeirra.
I tengslum við aukna plöntun trjáa á íslandi gæti átt sér stað sams-
konarrýrnun á Iíffræðilegum fjölbreytileika.
Since the Iron Age and up to this
century summer farming has
been an important and integrat-
ed part of Norwegian husbandry
(Kvamme and Norderhaug 1999).
The summer farm system was
based on the need to utilize the
resources of the outfields. The
mountain summer farms had
three main functions: (i) To pro-
vide summer pastures for the
animals in the outfields near the
summer farm, (ii) to be a produc-
tion place for milk and milk-
products, (iii) to serve as a base
for collection of winter fodder.
Norwegian summer farming
had its golden period in the mid-
dle of the 19th century, and in
1850 about 53 000 Norwegian
farmsteads had summer farms in
use (Reinton 1961). The number,
however, decreased towards the
end of the century, and this pro-
cess has continued throughout
the 20th century. In 1999 only
1738 summer farms were in use
(Statens Kornforretning 2000).
Grazing by different domestic
animals affected large areas and
formed the summer farm land-
scape in combination with mow-
ing of in-fenced areas, forests
and mires, collection of various
other types of fodder (branches,
leaves, lichen, etc.) and forest
logging.
The decrease in summer farm-
ing has permitted a large-scale
re-growth and secondary succes-
sion of mountain birch forests in
Norway (Aas and Faarlund 1995,
Austrheim 1998, Daugstad 2000).
The consequences of this re-
growth for the summer farm
landscape and vascular plant
species richness, exemplified
with results from a study in
Grimsdalen, southeast Norway,
is discussed in this paper.
Study area and methods
In Grimsdalen, Dovre municipali-
ty, summer farming is a more
than 400 years old tradition. In
the 1930s the utilisation period
at the summer farms, however,
decreased by three months, and
from the 60s until the 80s the
summer farms were abandoned,
except for three summer farms
still in use. The ceasing of felling
and mowing, and reduction in
grazing have resulted in a large-
scale re-growth of birch forest.
The investigated plots present-
ed in this paper, is situated
around three abandoned clusters
of summer farms. They are locat-
ed on basic rocks (Pedersen 1979)
and all sites are south-exposed
and situated between 940 and
1060 meter above sea level.
Average temperature during the
three warmest months is 9°C, e.g.
well below the potential sub-
alpine birch forest limit in this
area and just above the potential
Scots pine forest limit (Moen
1998). The annual precipitation
amounts 430 to 550 millimeters,
most of it as summer rain.
SKÓGRÆKTARRITIÐ 2001 I.tbl.
163