Vegetation in Iceland
One of the main differences between vegetation in Iceland and in neighbouring countries is how few vascular (higher) plant species grow wild here – a total of around 490. Iceland spent the last Ice Age under a glacier, which erased all or most of the vegetation that had previously established itself on the island. Other major contributing factors to the lack of species diversity in Iceland include its isolation and the limited means by which species could spread to Iceland. While some experts think that as much as a fifth of Iceland's flora survived the Ice Age, others believe that all species growing in Iceland today were carried here after the Ice Age by the wind, migrating birds or humans. Humans have brought a number of new species to Iceland over the years, both intentionally and unintentionally. Some plants introduced as garden plants have gradually made their way out into the wild.
Around half of all vascular plant species are found throughout the country, with the occasional exception of the central highlands, where growing conditions are much harsher than in coastal areas. These plants include flowering plants such as dandelions and buttercups. Other species have more limited distribution and grow only in certain areas of Iceland. Some of these are emblematic for the region in which they grow, such as harebells and yellow saxifrage in East Iceland and arctic poppies and small cow-wheat in the West Fjords. Still other species have been found at no more than a few locations – some are only known to grow at a single location. These rare species include northern spleenwort (Asplenium septentrionale) in Northern Iceland and wolf's-foot clubmoss (Lycopodium clavatum) in Southwestern Iceland. All the same, regional differences are not as great as one might expect for an island of Iceland's size.
Around 600 moss species, 700 lichen species and 2,000 species of fungi have been found in Iceland. As with vascular plants, Icelandic mosses, lichens and fungi show greater similarity to Northern European species than those found in North America, and a degree of regional variation can be seen. Some species are extremely common, while others are very rare. Certain moss species are among the most common plant species in Iceland, including the racomitrium mosses Racomitrium lanuginosum and Racomitrium canescens.
Sources: Eyþór Einarsson. 2005. Flóra og gróður Íslands. In ÍSLANDSATLAS (pp. 18-23). Reykjavík: Edda.
Hörður Kristinsson. 2010. A Guide to the flowering plants and ferns of Iceland. Reykjavík: Mál og menning.