Fróðskaparrit - 01.01.1987, Page 61

WHEN, HOW, AND WHENCE?
65
a large species pool), but that the subse-
quent inner colonization may be rather
slow, if immigration from the source pool
ceases and the further colonization of the
island group becomes (mainly) dependent
on dispersal from the populations which
have established themselves in (perhaps a
few) beach-heads.
My belief is that this is what happened
for a number of species after the initial lar-
ge-scale immigration during the first Post-
Glacial dispersal event. This large-scale
immigration ceased after some time and
left the further spread of the taxa over the
islands to the already established popula-
tions. Some of the species distribution pat-
terns we have found in the Faroes indicate
that the dispersal process within the islands
is still not completed.
This general overview is, however, not
the place to discuss individual species, or
differences within larger taxonomical
groups when it comes to colonizing the
Faroe Islands. Some such patterns are
treated in fuller detail in Enchell et al.
1986.
Acknowledgements
I thank S.-A. Bengtson for many fruitful and stimulat-
ing discussions about the history of the Faroese biota,
and S. Douwes for help with the figures. D. Bloch as-
sisted in various ways during field and laboratory work.
We acknowledge the assistance of Støðisútbúgvingin
(Academia Faeroensis) and the Natural History Muse-
um in Tórshavn for laboratory and logistical facilities
and support. The Swedish Natural Science Research
Council is acknowledged for financial support (to S. -A.
Bengtson).
References
Andersen, B.G. 1980. The deglaciation of Norway
after 10,000 B.P. - Boreas 9: 211-216.
Anoymous 1973. Taxationsprotokol 1873. - J. H.
Schultz 1873 (reprinted 1973, Tórshavn)
(in Danish).
Arndt, W. 1928. Des Sússwasserschwamm Heteromey-
enia ryderi Potts auf den Faróern. - Zool. Anz. 77:
156-166.
Ashmole, N.P. 1979. The spider fauna of Shetland and
its zoogeographic context. - Proc. Roy. Soc. Edin-
burgh 78B: 63-122.
Ashworth, A.C. 1973. The climate significance of a
Late Quaternary insect fauna from Rodbaston Hall,
Staffordshire, England. - Ent. Scand. 4: 191-205.
Bengtson, S.-A. 1981. Terrestrial invertebrates of the
Faroe Islands: III. Beetles (Coleoptera): Check-list,
distribution, and habitats. - Fauna norv. Ser. B. 28:
52-82.
_ 1982. Lavere dyr pá land og i ferskvand. - In: Nørre-
vang, A. and Lundø, J. (eds), Danmarks Natur,
Part 12, Færøernes natur. Politikens Forlag, Copen-
hagen, pp. 123-141 (in Danish).
_ and Hauge, E. 1979. Terrestrial invertebrates of the
Faroe Islands: I. Spiders (Araneae): Check-list,
distribution, and habitats. - Fauna norv. ser. B 26:
59-83.
_ and Bloch, D. 1983. Island land bird population
densities in relation to island size and habitat quality
on the Faroe Islands. - Oikos 41: 507-522.
Bjørk, E. A. 1985. Færøsk bygderet (Faroese local law).
- Matrikulstovan, Tórshavn (3 vols, Animal husban-
dry, property rights, and shorerights; in Danish).
Braendegaard, J. 1928. Araneina. - Zoology of the
Faroes 47: 1-28. Copenhagen.
Brinck, P. 1966a. Animal invasion of Glacial and Late
Glacial terrestrial environments in Scandinavia. -
Oikos 17: 250-266.
_ 1966b. Djurvárlden och det nordiska landskapets ut-
veckling - Norsk Ent. Tidsskr. 13: 205-244 (in Swe-
dish)
Buckland, P.C. 1988. North Atlantic faunal connec-
tions: Introductions or endemics? - Ent. scand.
Suppl. 32: 7-29.
Coope, G.R. 1969. The contribution that the Coleop-
tera of Glacial Britain could have made to the subse-
quent colonization of Scandinavia. - Opusc. ent. 34:
95-108.
_ 1979. The Carabidae of the Glacial Refuge in the
British Isles and their contribution to the Post Glaci-
al colonization of Scandinavia and the North Atlan-
tic islands. - In: Erwin, T.L., Ball, G.E., and White-