Fróðskaparrit - 01.01.1998, Síða 257

ELDRI HOLOSENAR RANNSÓKNIR ÚR SAKSUNARDALI
OG UPPRUNIN TIL TAÐ FØROYSKA BIOTA
263

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Strat.
Peat
'clay'
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Peot
Fig. 3. Pollen and spore diagram from Saksunardalur. All taxa expressed as percentages oftotal land pollen
extiuding alien arboreal taxa. • = < 2%.
Mynd 3. Strikumynd av flogsáð og grókorni úr Saksunardali. 011 taxa eru lýst sum prosentpartur av øllum
landflogsáð, undantikin fremmand taxa, sum liva á trøum. • = < 2 %.
provide habitat for the water beetles. The
dytiscids Agabus bipustulatus, Hydroporus
nigrita and H. pubescens are fairly eury-
topic in their requirements, occurring in
both oligotrophic and mesotrophic waters
(Nilsson and Holmen, 1995), whilst the hy-
drophilid Anacaena globulus also extends
to streams, wet meadow and grassland
(Hansen, 1987). Coelostoma orbiculare,
found in shallow water and moss at the wa-
ter’s edge (Koch, 1989), is not currently
recorded from the Faroes, despite extensive
recent pit fall trapping of the beetle fauna
(Bengtson, 1981; Dinnin et al. unpubl.), al-
though it is widespread in Central and
Northem Europe. Whether it has suc-
cumbed to the large scale modification of
virtually all of Faroes’ wetlands by human
activity, or has been overlooked, has yet to
be ascertained.
Several of the other species recovered
from the Saksunardalur samples are now
rare in the islands. The staphylinid Lathro-
bium brunnipes is present in most samples,
yet modern specimens are restricted to a
single locality on Vagar. It shows a similar
pattern of being a frequent fossil and rare at
the present day in southern Iceland (Buck-
land et al., 1991).
The fossil assemblage is typical of most
remote islands in the paucity of monopha-
gous or oligophagous phytophages. Of the
two weevils, Otiorhynchus nodosus is
polyphagous in most semi-natural habitats
in Faroe, the larvae feeding on plant roots,
whilst Micrelus ericae is usually found on
Calluna vulgaris, although occasionally it
may be found on the flowers of Erica spp.
The elaterid Hypnoidus riparius and the
scirtid Elodes minuta are also characteristic
of wet grassland and meadow.
The pollen data
The visible black ash layer at the pollen site
was 1.0 cm thick and was underlain by
black humified peat. Above the ash layer