Colonization of lichens on Surtsey 1970–2006

A list of lichen species from the volcanic island Surtsey is presented. A total of 87 species have been recorded since the first three species appeared in 1970. Notes on distribution and short description of the main lichen communities are given. Possible colonization routes to the island are discussed. Four of the species treated are new to iceland, Gyalidea fritzei and Psilolechia clavulifera and two species, one Lecanora and one Stereocaulon which probably are new to science. Two further species belonging to Lecanora, provisionally determined as L. albescens and L. semipallida, are probably new to iceland. The primary colonization resembles what has been recorded on other lava fields in iceland. Lichen species established very slowly on Surtsey with relatively few species found during the first two decades, in 1984 only 17 species had been recorded. That number almost doubled during the next six years, 31 species had been recorded on the island by 1990 and there has been a constant accumulation of species since then. The lichen colonization benefitted from the activity of gulls. Many species were probably dispersed by the trampling birds and colonized the naked lava rock around the breeding area. Later soil formation started in connection with the gull colony and the first colonizers were replaced by other species. The palagonite tuff has only recently been colonized by lichens and on the coastal rocks of the island only one lichenized species has been found so far.