The Great Kobuk Sand Dunes of the Kobuk Valley National Park in northwestern Alaska (67° 07.636' N, 159° 02.371' W) were surveyed for lichens in August of 1999 and 2000. These 62 sand dunes are located in the Kobuk River valley about 160 km east of the town of Kotzebue, Alaska and the Chukchi Sea. Annual precipitation and frost-free days at the sand dunes, nearby sub-arctic forests and tundra average 203mm and 70 days, respectively. The sand dunes were created during the late Pleistocene and consist of calcareous sands eroded from the Brooks Range by glaciers and transported to their present location by the Kobuk River and wind. Much of the material has been stabilized by vegetation and the remaining active dunes are now separated from the Kobuk River by coniferous forest. At the perimeter and within the active dunes area, vegetation islands in various stages of succession and soil stabilization can be found. To examine lichen communities characteristic of the various successional stages, monitoring plots were located on a gradient of weakly stabilized sand to fully forested habitats. Lichens identified from the sand dunes and surrounding habitats comprise 63 genera and 160 species, many with circumpolar arctic-alpine and Amphi-Beringian distributions. Results from this research will assist the US National Park Service in the development of dune conservation strategies and visitor-use regulations, and contribute to the knowledge of the cryptogamic flora of the Beringian region.

Key words: Alaska, lichens, sand dunes, succession