Nearctic realm

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The Nearctic realm is one of the eight biogeographic realms constituting the Earth's land surface.

The Nearctic realm covers most of

The Northern Mexico bioregion includes the mild-winter to cold-winter deserts and xeric shrublands, warm temperate and subtropical pine and pine-oak forests, and Mediterranean climate ecoregions of the Mexican Plateau, Baja California peninsula, and the southwestern United States, bordered to the south by the Neotropical Trans-Mexican Volcanic Belt.^[1] This region also includes the only subtropical dry broadleaf forest in the Nearctic realm, the Sonoran–Sinaloan transition subtropical dry forest.

In terms of

Although North America and South America are presently joined by the Isthmus of Panama, these continents were separated for about 180 million years, and evolved very different plant and animal lineages. When the ancient supercontinent of Pangaea split into two about 180 million years ago, North America remained joined to Eurasia as part of the supercontinent of Laurasia, while South America was part of the supercontinent of Gondwana. North America later split from Eurasia. North America has been joined by land bridges to both Asia and South America since then, which allowed an exchange of plant and animal species between the continents, the Great American Interchange.

A former land bridge across the

• Order Primates – the first primate/proto-primate, Purgatorius, originated in the Early Paleocene of the Nearctic.
• Family Canidae – dogs, wolves, foxes, and coyotes.
• Family Camelidae – camels and their South American relatives including the llama. Now extinct in the Nearctic
• Family Equidae – horses, donkeys and their relatives. Now only found in the Nearctic as feral horses.
• Family
  Tapiridae – tapirs
  now extinct in the Nearctic.
• Family Antilocapridae – last survivor of which is the pronghorn.
• Subfamily Tremarctinae (short-faced bears) – including the giant short-faced bear (Arctodus simus). The only surviving member of the group is the spectacled bear (Tremarctos ornatus) of South America.

Flora and fauna endemic to the Nearctic

One

Plant families endemic or nearly endemic to the Nearctic include the Crossosomataceae, Simmondsiaceae, and Limnanthaceae.

Nearctic terrestrial ecoregions

See also

• List of ecoregions in Canada (WWF)
• List of ecoregions in Mexico (WWF)
• List of ecoregions in the United States (WWF)

References

• Abell, R.A. et al. (2000). Freshwater Ecoregions of North America: A Conservation Assessment Washington, DC: Island Press, Freshwater Ecoregions of North America: A Conservation Assessment.
• Flannery, Tim (2001). The Eternal Frontier: an Ecological History of North America and its Peoples. Grove Press, New York.
• Ricketts, Taylor H., Eric Dinerstein, David M. Olson, Colby J. Loucks, et al. (1999). Terrestrial Ecoregions of North America: a Conservation Assessment. Island Press, Washington DC., Terrestrial Ecoregions of North America: A Conservation Assessment.

External links

Wikimedia Commons has media related to Nearctic.

Wikivoyage has a travel guide for North American wildlife.

• Map of the ecozones
• Nearctica, The Natural World of North America
• "Nearctic Region" .
  New International Encyclopedia
  . 1905.