Fróðskaparrit - 01.01.1992, Page 50

54
THE EXOTIC LAND PLANARIAN .. .
trolled import of goods from
abroad. Many supply ships came
from Scotland, though some came
from as far away as New Zealand
and South America, delivering
vegetables, meat and other produce
to Tórshavn.
Since 1976 there has been a regular
summer ferry service between the
Faroes and Shetland/Scotland, so
allowing the possibility of tourists
retuming to the Faroes with plant
material (c.f. Bloch, 1992).
Introduction of plant material from
both northem and southem hemi-
sphere countries has been initiated
by the Nordic arboreta. In particu-
lar, material originating from a
Nordic arboretum expedition to
New Zealand/Tasmania/Australia
in 1974/75 has been introduced
(albeit indirectly) to the Faroes and
subsequently distributed.
Each of the above points remains as a
contender for the immigration route for A.
triangulata, and it is clearly possible that
specimens of the land planarian (adults,
juveniles or egg capsules) may have been
accidentally introduced to the Faroes on
more than one occasion in the past, directly
and/or indirectly from New Zealand.
Furthermore, it is highly likely that the land
planarian had already reached the islands
some years prior to the first sighting in
1982, particularly as specimens are easily
overlooked by the inexperienced eye.
Since land planarians in general are
prone to desiccation (Ball and Reynoldson,
1981), and as A. triangulata is very suscep-
tible to mechanical damage (Willis and
Edwards, 1977) and temperatures above
20° C which are lethal (Blackshaw and
Stewart, 1992), ideal media for the trans-
port of the land planarian are cool, moist
soil and moss. Thus, potted plants and
plants with root-systems bound in moss
which are transported under cool storage
conditions seem excellent vehicles for the
long-distance passive migration of these
soil organisms. Also possible is the trans-
port of land planarians with freshly har-
vested potatoes or other root crops, and
smaller juveniles may be able to find refuge
within the outermost scales of plant bulbs
(Willis and Edwards, 1977), or between the
outer foliage of certain vegetables (e.g.
cabbage).
Adaptation to Faroese conditions
With regard to an understanding of the land
planarian’s apparent success in the Faroe
Islands, it is perhaps worthwhile to consid-
er how well plant material from New
Zealand has adapted to Faroese conditions.
The plant material originating from the
Nordic arboretum expedition to New
Zealand/Tasmania/Australia in 1974/75
was first propagated in arboreta at Hørs-
holm, near Copenhagen in Denmark, and at
Milde, near Bergen in Norway, after which
material was sent to the Faroes (Ødum,
1989). As the present-day arboretum was
not yet established, the material was plant-
ed in the conservator’s garden in Tórshavn