Holarctic

The Holarctic is the name for the biogeographic realm that encompasses the majority of habitats found throughout the northern continents of the world, combining Wallace's Palearctic zoogeographical region, consisting of North Africa and all of Eurasia (with the exception of the southern Arabian Peninsula, Southeast Asia, and the Indian subcontinent), and the Nearctic zoogeographical region, consisting of North America, north of Mexico. These regions are further subdivided into a variety of ecoregions. Many ecosystems, and the animal and plant communities that depend on them, are found across multiple continents in large portions of this realm. The continuity of these ecosystems results from the shared glacial history of the realm. The floristic Boreal Kingdom corresponds to the Holarctic realm. Within the Holarctic realm, there are a variety of ecosystems. The type of ecosystem found in an area depends on the latitude and local geography. In the far north, a band of arctic tundra circles the shore of the Arctic Ocean. The ground beneath this land is permafrost, frozen year-round. In these difficult growing conditions, few plants can survive. South of the tundra, the boreal forest stretches across North America and Eurasia. This land is characterized by coniferous trees. South of here, the ecosystems become more diverse. Some areas are covered in temperate grassland, while others are covered in temperate forest, dominated by deciduous trees. The southern extent of the Holarctic typically reaches into the desert, which is dominated by plants and animals adapted to the dry conditions (Schultz 2007).