Náttúrufræðingurinn - 1998, Blaðsíða 94

scape and land-use around Norwegian alu-
minium smelters. Environm. Pollut. 8.113-121.
Haukur Jóhannsson & Sigmundur Einarsson 1988.
Krísuvíkureldar I. Aldur Ögmundarhrauns og
Miðaldalagsins. Jökull 38. 71-87.
Kristinn P. Magnússon 1984. Ahrif loftmengunar
frá Alverinu í Straumsvík. Ritgerð við Líf-
fræðiskor Háskóla Islands.
Murray, F. 1981. Effects of Fluorides on Plant
Communities around an Aluminium Smelter.
Environm. Pollut., Ser. A 24. 45-56.
Richardson, D.H.S. & Puckett, K.J. 1971. Sulphur
Dioxide and Photosynthesis in Lichens. í: Ferry,
B.W., Baddeley, M.S. & Hawksworth, D.L.
(ritstj.), Air Pollution and Lichens. The Athlone
Press of the University of London. Bls. 283-
298.
SUMMARY
Plant community changes around the
ALUMINIUM SMELTER IN STRAUMSVÍK,
ICELAND
The aluminium smelter in Straumsvík, SW-Iceland,
has been in operation since 1969. In 1980, fluoride
emission from the smelter was 1100 tons/year on
average. During the period 1982-1991 itdecreased
to 500 tons/year and has since 1992 been approxi-
mately 140 tons/year, as a result of improved
cleaning system. Sulphur dioxide emissions have
remained near 1500 tons/year on average the whole
period 1980-1997.
The normal vegetation of this lava field consists
mainly of carpets of Racomitrium lanuginosum,
with Empetrum nigrum ssp. hermaphroditum on
exposed sites (Fig. 2). Sheltered depressions in the
lava fields are characterized by heath vegetation,
dominated by Calluna vulgaris, Empetrum nigrum
ssp. hermaphroditum, Vaccinium uliginosum and
Arctostaphylos uva-ursi (Fig. 1). Exposed lava
peaks, sticking out above the Racomitrium carpet,
are covered with lichens (Fig. 3), mainly Stereo-
caulon vesuvianum, Pertusaria corallina, Ochro-
lechia lactea and Porpidia melinodes.
During the first 20 years of operation consider-
able changes were observed in the vegetation within
1 km distance around the smelter. The vegetation
has been severely affected by air pollutants closest
to the factory. The Racomitrium carpets in 300 m
distance have become black, like they are more or
less bumed up (Fig. 8 and 9), the lichens are dead
and the rock faces are bare (Fig. 7), but Empetrum
nigrum has increased its coverage. In sheltered sites
all dwarf shrubs have disappeared from the heath
vegetation except Empetrum nigrum, which has in-
creased from 16 to 70% coverage (Fig. 6).
Vegetation analyses using the point quadrat
method were made in these lava fields in the fall
1989. Two sites were selected in 300 m distance
from the factory, one sheltered in a depression and
the other exposed. For comparison, two similar
sites were selected in 2 km distance from the fac-
tory, where the vegetation appeared to be normal.
The results of these analyses are shown in figs. 4—
6. At both sites the species diversity has declined
considerably in 300 m distance, as compared with 2
km distance from the smeltcr (Fig. 11).
It is remarkable how resistant Empetrum nigrum
seems to be, the only surviving dwarf shmb in 300
m distance from the factory. It not only survives,
but even increases its cover substantially as it colo-
nizes the area left by the declining Racomitrium
carpets. However, it was noticed that while the air
pollution didn’t affect its reproduction, the older
branches were damaged after several years of expo-
sure, as seen in fig. 6.
Similar experience has been reported near alu-
minium smelters in northem Norway (Gilbert
1975), where Calluna vulgaris in a dwarfshmb
heath was replaced by Empetrum nigrum and Salix
repens. In that case the lichens and the bryophytes
were also heavily damaged.
As a result of this investigation, the following
general conclusions were made:
1. Damage of vegetation is primarily to be ex-
pected on exposed surfaces like hills, cliffs, lava
peaks or on trees.
2. Damage of vegetation occurs mainly on the
side facing the source of pollutants.
3. Most damage is to be expected in the direc-
tion of prevailing winds from the origin of pol-
lutants.
4. Bryophytes and lichens are much more af-
fected than grasses and flowering plants sheding
their leaves every year.
5. Individual species of these plant groups re-
act to a different extent to the exposure to pol-
lutants.
PÓSTFANG HÖFUNDAR/AuTHOr's AdDRESS
Hörður Kristinsson
Náttúrufræðistofnun Islands/
Icelandic Institute of Natural History
Pósthólf/P.O.Box 180
IS-602 Akureyri
Netfang/E-mail
hkris@nattfs.is
252