Full-text - Norsk entomologisk forening

Abundance and diversity in the fauna of nocturnal moths
at two sites in South Norway
ALF BAKKE
Bakke, A. 1974. Abundance and diversity in the fauna of nocturnal moths at two
sites in South Norway. Norsk ent. Tidsskr. 21, 173-184.
From 1969 to 1971, light-trap catches were made every night from early spring
until late autumn at Grimstad, 2 km from the coast, and at Amli, 44 km further
north in the inland of South Norway. More than 29 thousand specimens from the
families Notodontidae, Saturniidae, Endromididae, Lasiocampidae, Lymantriidae,
Drepanidae, Polyplocidae, N octuidae, Hylopilidae, and Plusiidae, comprising 230
species, were trapped. Numbers of each species caught at the two sites every year
are listed. The flight periods of the various species in 1971 are indicated. Comparisons
are made with records from the same area about a hundred years ago,
between the records from the two sites, and between the records from the various
years. An attempt is made to estimate the percentage of the total number of species
collected in a year which is likely to be trapped in periods of ten days during the
season.
All Bakke, Norwegian Forest Research Institute, N-1432 As-NLH, Norway.
Human influence on nature has considerably on a precisely described method, to collect
changed the distribution and abundance of information on the flight periods of the speplant
and animal life during the last century. cies and on the abundance and diversity of
This has been recorded in many vertebrates. species during the season, to compare the
Changes in the composition of the invertebrate present fauna with the records of earlier
fauna are more difficult to notice because periods, especially those of Schneider (1882),
very few reports are available on the fauna to compare the fauna of two sites within the
of earlier times which might have made a same area, but with different distance from
comparison possible. This demonstrates the the coast, and to study changes in the abunnecessity
of carrying out faunistical inventory dance of the various species during the threework
which can provide a basis for ecological year period.
~tudies of future generations.
Some families of Lepidoptera belong to the
groups of insects which faunistically and
systematically were studied in Norway during
MATERIAL AND METHODS
the 19th century. From a few areas faunistic
data were published. The southern part of the Areas of investigation
county of Aust-Agder, on the south coast of The light-traps were situated at two sites in
Norway, is one of these areas (Schneider the county of Aust-Agder AAy (Strand
1882). 1943) in southern Norway (Fig. 1): one at
At two sites in the same area, light-trap Dommesmoen horticultural school, Grimstad,
catches were made from 1969 to 1971, as altitude 30 m, approximately 2 km from the
part of a bio-climatological programme sup­ coast; the other at Amli, altitude 150 m, 1
ported by the Agricultural Research Council km south of the commercial centre of the
of Norway. The objects of the study were to community, approximately 37 km from the
analyse the composition of the fauna based coast and 44 km north of Grimstad. Both