Bakalin. Hepatic distribution patterns in the Russian Far East

Hepatic distribution patterns in the Russian Far East

Vadim A. BAKALIN ^{1, 2}
¹ Botanical Garden-Institute FEB RAS, Vladivostok, Russia
² Institute of Biology and Soil Science, Vladivostok, Russia

The liverwort flora of the Russian Far East is the most taxonomically diverse regional flora within Russia including 405 species, or ca. 80 % of total hepatic diversity. Almost 14 % (55 species) are known in Russia from this region only. The main reasons underlying high hepatic diversity are: the strong diversity of thermal regimes and humidity conditions in the Russian Far East, diverse orography and degree of geological stability, the absence of continuous ice cover in most parts of territory during the Cenozoic glaciations and wide distribution of modern glaciers, and the close modern and ancient floristic contacts between this territory and North America, East Siberia and Southeast Asia. Many taxa have limited distribution in the Russian Far East: namely northern, southern and western, or else are either known in localities isolated from the main area body, or are endemics. The floras of landmasses with continental and oceanic climates are predictably different. Species richness in the insular and peninsular parts of the Far East and is ca. 5 times that of the continental part. The increasing proportion of Temperate species from the North to the South and a parallel decrease of Arctic species is obvious, but in the insular part these changes are not as evident as in the continental section. The species diversity exhibits unique centers of concentration, but is unevenly distributed within the Russian Far East. The highest number of species is recorded in the mountainous region of the central Sredinnyj Range in Kamchatka, the eastern Chukotka Peninsula, the southern Vostochno- Sakhalinskiye mountains, in Sakhalin Island, the southern flank of Sikhote-Alin Range, and South Kurile Islands. Another likely center of diversity in the Russian Far East is the coastal range westward of Sea of Okhotsk where, unfortunately, the hepatics have not yet been studied.