Subarctic Eurasia covers most of the land mass of Russia and the Nordic countries – Iceland, Norway, Sweden, and Finland – and makes up the northern section of the Palearctic realm with four major subrealms as defined in the Bioregions 2020 framework -- Palearctic Tundra, Scandinavia & West Boreal Forests, Siberia & East Boreal Forests, and the Sea of Okhotsk. Palearctic Tundra stretches across the Eurasian continent, surrounding the eastern half of the Arctic Circle. The boreal and coastal forests of Scandinavia extend eastward and meet the Ural Mountains. Siberia is a vast expanse of boreal forests and taiga with some alpine tundra covering much of Russia. The Sea of Okhotsk& Bering Tundra subrealm, which includes Sakhalin Island, is particularly important for biodiversity with dense old-growth forests and one of the most biodiverse marine regions in the world, a feeding ground for four whale species, seals, and abundant fish populations.