Náttúrufræðingurinn - 1998, Page 18

Þóra Ellen Þórhallsdóttir 1998. Endurheimt vot-
lendis. í: íslensk votlendi. Verndun og nýting
(ritstj. Jón S. Ólafsson). Háskólaútgáfan (í
prentun).
Þóra Ellen Þórhallsdóttir, Jóhann Þórsson, Svafa
Sigurðardóttir, Kristín Svavarsdóttir &
Magnús H. Jóhannsson 1998. Röskun
votlendis á Suðurlandi. I: Islensk votlendi.
Verndun og nýting. (ritstj. Jón S. Ólafsson).
Háskólaútgáfan (í prentun).
Þröstur Eysteinsson 1998. Endurheimt Álfta-
vatns á Höfða (skriflegar upplýsingar,
5.2.1998).
■ SUMMARY
INITIATION OF WETLAND ReSTORATION IN
ICELAND
Extensive drainage of wetlands occurred in Ice-
land during the period 1945-1985. In the low-
lands only a few areas remain intact. With recent
changes in agriculture some of the drained areas
have fallen out of use. In 1996, an effort was
started by the Ministry of Agriculture to restore
some of the drained wetlands. In this paper op-
erations at two of the sites are described and first
results presented.
At Hestur in SW Iceland a 35 ha sloping mire,
drained in 1977, was selected as an experimental
site for the project. In the summer of 1996 the
water table was monitored and vegetation cover
and composition studied in the mire (Fig. 1). The
area was rewetted in October 1996 by filling in
the drainage ditches with the former excavated
peat. Monitoring of water table was continued
at the site in 1997. The blocking of the ditches
led to a considerable elevation'of the water table.
In the summer of 1996 the water table was gen-
erally in the range of 20-100 cm below surface
and fell down to 160 cm in the driest parts of the
mire. In 1997, on the other hand, the water table
was within 40 cm of the surface over most of the
mire area (Fig. 3) and did not fall below 90 cm in
the driest parts. Carex nigra was the dominant
species in the vegetation of the mire in 1996 (Fig.
7). It had not been greatly affected by the drain-
age. Several other wetland species remain in low
abundance in the vegetation. They will probably
respond to the elevated water table and increase
their abundance again. Grass species that gained
abundance following the drainage of the mire are
likely to decline (Fig. 6-7).
At Kolavatn in southern Iceland, a 7 ha shal-
low, drained lake in a mire area was restored (Fig.
12-13). A 40 m long outlet from the lake to a
drainage ditch was filled with soil material in
early July 1997. The water level rose consist-
ently over the summer and in early October the
lake basin was full (Fig. 14). By that time water-
fowl had started to visit the lake. The site was
not frequented by waterfowl before the restora-
tion and overall birdlife was poor.
Conditions for wetland restoration in Iceland
are considered favourable as most of the drained
mires have not been intensively cultivated or ex-
cavated. They still have semi-natural vegetation
which is relatively rich in wetland species. In
most cases the establishment of suitable hydro-
logical conditions should be sufficient for the
restoration of mires and other wetland areas.
PÓSTFANC HÖFUNDAR/AuTHOr's
ADDRESS
Borgþór Magnússon
Rannsóknastofnun landbúnaðarins/
Agricultural Research Institute
Keldnaholt, 112 Reykjavík
Netfang/e-mail:
borgthor@rala.is
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