Euro-Siberian region
The boreal and temperate Euro-Siberian region is the largest ecoprovince in the Palearctic realm. It transitions from tundra in the northern reaches of Russia and Scandinavia to the vast taiga: the boreal forests which run across the north of Eurasia. South of the taiga is a belt of temperate broadleaf and mixed forests and temperate coniferous forests. The vast Euro-Siberian region is characterized by many shared plant and animal species, and has affinities with the temperate and boreal regions of the Nearctic ecoregion of North America. Eurasia and North America were often connected by the Bering land bridge, and have similar mammal and bird fauna. Many Eurasian species migrated to North America, and some North American species have also moved to Eurasia. Many zoologists consider the Palearctic and Nearctic to be a single Holarctic realm. The Palearctic and Nearctic also share many plant species, which botanists call the Arcto-Tertiary Geoflora.
