Geografia | lkjh
Correspon al reialme Neartic.
Les Rocky Mountains s’extenen per tot l’oest, de Canadà a Mèxic, (orogènia laramy 80-55ma) i les Appalachian Mountains a l’est (orogènia caledonia 490-390 Ma).
Els principals rius són el Yukon, Mackenzie a Alaska, el Mississipi i Missouri al centre, el Colorado i el Río Grande que limita amb Mèxic.
-
- The Canadian Shield bioregion (55 a 70º latitud) extends across the northern portion of the continent, from the Aleutian Islands to Newfoundland. It includes the Nearctic’s Arctic Tundra and Boreal forest ecoregions. In terms of floristic provinces, it is represented by part of the Canadian Province of the Circumboreal Region.
- The Eastern North America bioregion includes the temperate broadleaf and mixed forests of the Eastern United States and southeastern Canada, the Great Plains temperate grasslands of the Central United States and south-central Canada, the temperate coniferous forests of the Southeastern United States, including Central Florida. In terms of floristic provinces, it is represented by the North American Atlantic Region and part of the Canadian Province of the Circumboreal Region.
- The Western North America bioregion includes the temperate coniferous forests of the coastal and mountain regions of southern Alaska, western Canada, and the Western United States from the Pacific Coast and Northern California to the Rocky Mountains, as well as the cold-winter intermountain deserts and xeric shrublands and temperate grasslands and shrublands of the Western United States. In terms of floristic provinces, it is represented by the Rocky Mountain region.
- Northern Mexico and Southwestern North America. The Northern Mexico bioregion includes the mild-winter to cold-winter deserts and xeric shrublands of northern Mexico, Southern California, and the Southwestern United States, including the Chihuahuan, Sonoran, and Mojave Deserts. The Mediterranean climate ecoregions of the Southern and Central Coast of California include the California chaparral and woodlands, California coastal sage and chaparral, California interior chaparral and woodlands, and California montane chaparral and woodlands. The bioregion also includes the warm temperate and subtropical pine and pine-oak forests, including the Arizona Mountains forests and the Sierra Madre Occidental, Sierra Madre Oriental, and Sierra Juarez and San Pedro Martir pine-oak forests.