Ahti T. Terricolous lichens in East Asian boreal vegetation and flora in a circumpolar comparison. In: The East Asian Flora: and its role in the formation of the world’s vegetation

A circumpolar comparison of terricolous lichens in East Asian boreal vegetation and flora

Teuvo T. AHTI
Finnish Museum of Natural History, Helsinki, Finland

Terricolous, fruticose lichens are dominant members in the ground layer of xeric, open woodlands in extensive areas of continental sectors of the boreal zone in East Asia. Certain species are also common in the bryophyte-dominated mesic and submesic community types. In addition, lichens are often dominant on thin soil over open rock outcrops, in boulder fields, on sand-dunes, and on hummocks or even wet surfaces of peatlands. Their remarkable ecological role tends to increase towards the polar or alpine timberlines and in various forest successions on welldrained soil, but also on peatlands after forest fires or logging, then binding humus and parent soil against erosion, and forming lichen-rich, seral communities. The major lichen species in East Asian vegetation are largely circumpolar (e.g., Cladonia stellaris), occupying similar sites and subzones elsewhere in the circumboreal zone. Another element is present in all four boreal coastal regions (e.g., Cladonia maxima). The East Asian element is small, including Cladonia cineracea and some coastal species. The Amphiberingian element includes Cladonia alaskana, C. alinii, C. jacutica, C. kanewskii, C. nipponica, C. pseudoevansii, C. scotteri, and Flavocetraria minuscula. Cetraria laevigata and Cladonia wainioi occupy similar ecological niches extending to eastern North America. The arid boreal sectors (as in the Sakha Republic) include areas where calcicolous, primarily arctic or steppe lichens may form soil crusts with numerous tiny crustose species.