Jökull - 01.01.2004, Blaðsíða 12

Hafdís Hanna Ægisdóttir and Þóra Ellen Þórhallsdóttir
Table 1: A comparison of vascular species richness and endemism on selected oceanic islands at latitudes
>30◦N and >30◦S. Greenland is included because of its geographical setting as Iceland’s closest neighbour.
– Samanburður á tegundaauðgi æðplantna og fjölda einlendra tegunda á völdum úthafseyjum á breiddar-
gráðunum >30◦N og >30◦S. Grænland er tekið með í samanburðinn vegna nálægðar sinnar við Ísland.
Island or archipelago ref. latitude isolation approx. area indigenous endemic %
approx. km to of island or vascular taxa endemism
nearest continent island group species
Greenland 1 59◦46’-83◦41’N 2,175,600 497 15 3.0
383,600a)
Svalbard 2 74–81◦N 930 62,000 164 2–3? 1.2?
Iceland 3 63◦23’–66◦32’N 810 (Scotl.), 970 (Norw.) 103,000 480 (1)d) (0.3)
Faroe islands 1 62◦N 330 (Scotl.), 600 (Norw.) 1,399 250 (1)d) (0.4)
French Southern 1 37◦41’-48◦50’S >2,000 7,829 50 11 22.0
Territoriesb)
Chatham island 1 43◦58’S 800 965 320 40 12.5
subantarctic islands 1,5 49◦42’–54◦37’S 200–800c) 949 ca. 250 35 ca. 14
(Auckland, Campbell,
Antipodes and
Macquarie islands)
Falkland islands 1 52◦S 530-550 12,200 165 14 8.5
a) area of ice-free land (Böcher and Petersen, 1997)
b) includes the archipelagos of Crozet and Kerguelen and the volcanic islands of Amsterdam and St Paul
c) refers to distance to New Zealand
d) the bracketed figure of 1 refers to the same species for both Iceland and the Faroe islands, the apomictic Alchemilla
fareoensis.
References, 1) Davis et al., 1996; 2) Elvebakk, 1997; 3) Válisti 1. Plöntur, 1996; 4) Scott, 1985; 5) McGlone, 2002.
amined and tested first. Here, the hypothesis of a
Holocene age for the North Atlantic flora must be re-
garded as simpler as it requires fewer environmental
and biological assumptions. Since the subject was
first broached over a century ago, there have been
several paradigm shifts, from the early acceptance of
tabula rasa to glacial survival in the mid 20th cen-
tury. At present, the pendulum seems to be moving
towards tabula rasa again (Brochmann et al., 2003)
but whether that will be the end of the debate is hard
to say. Only more studies and discussions in the fu-
ture will help us further in our search for an answer
on the history of the North Atlantic flora.
Acknowledgements
The authors like to thank Árni Einarsson and Kristján
Sæmundsson for useful comments on an earlier draft
of this paper. We would also like to thank Hörður
Kristinsson and Ólafur Ingólfsson for permission to
use their pictures.
ÁGRIP
Kenningar um sögu flórunnar við N-Atlantshaf
Í greininni er fjallað um þróun ördeyðu- og miðsvæða-
kenninganna frá lokum 19th. aldar en þær hafa verið
miðpunktur skoðanaskipta um uppruna og sögu flór-
unnar við Norður Atlantshaf allt fram á okkar daga.
Ummerki eftir ísaldarjökulinn í Skandinavíu urðu um
miðja 19. öld kveikjan að hugmyndum um að allt líf-
ríki hafi dáið út á jökulskeiðum ísaldar en borist þang-
12 JÖKULL No. 54