Commentary: Colonization of the arctic archipelago Svalbard

Abstract

ISSN 1948-6596 news and update commentary Colonization of the arctic archipelago Svalbard We have more knowledge on colonization to the Arctic Archipelago of Svalbard than to any other arctic region. Previous analyses include the only native terrestrial mammals, reindeer (Flagstad and Roed 2003) and arctic fox (Dalen et al. 2005), the only fresh water fish, arctic charr (Brunner et al. 2001), several Daphnia species (Weider et al. 1999), the moth Plutella xylostella (Coulson et al. 2002), and many vascular plant species (Brochmann et al. 2003, Alsos et al. 2007). Re- cently, also the colonization routes for the only resident terrestrial bird, the Svalbard rock ptarmi- gan (Lagopus muta ssp. Hyperborea, Figure 1) have been analysed (Sahlman et al. 2009). Svalbard represents an ideal model system for studying colonization for several reasons. It was almost entirely glaciated during the last gla- cial maximum 20,000 years before the present (Landvik et al. 1998, Landvik et al. 2003) and thus glacial survival can mainly be ruled out as explana- tion for the presence of species. Fossil evidence indicates sparse arctic vegetation from 10,000 years B.P. (Birks et al. 1994), which thus gives the maximum time frame for colonization events. It is geographically isolated, and the distances to near- est lands are 470 to northeast Greenland, 650 km to N Norway, 870 km to Novaya Zemlya, and 240 to the high arctic archipelago Frans Josef Land. The Svalbard rock ptarmigan, L. muta ssp. hyperborea, is restricted to Svalbard and Frans Josef Land. It belongs to the large rock ptarmigan species complex (Lagopus muta) which originated in Beringia (Lucchini et al. 2001), and now consists of up to 30 different subspecies which are found throughout the circumpolar region as well as in many temperate alpine regions (Storch 2007). The Svalbard rock ptarmigan is commonly seen from March to October, but it is a puzzle where they spend the winter, as the dark polar night makes visual observations difficult. Rock ptarmigan in other regions have seasonal migrations of up to 500 km (arctic Russia) or 1,000 km (coastal Greenland). It is assumed that Svalbard rock ptar- migans stay in Svalbard during winter, possibly Figure 1. The Svalbard rock ptarmigan (Lagopus mutus ssp. hyperboreus) colonized Svalbard from Russia or Greenland according to a recent study (Sahlman et al. 2009). Photo: Bjorn Erik Sandbakk. frontiers of biogeography 1.2, 2009 — © 2009 the authors; journal compilation © 2009 The International Biogeography Society