Editing Nearctic realm (section)

==Major ecological regions==
The [[World Wildlife Fund]] (WWF) divides the Nearctic into four '''[[bioregions]]''', defined as "geographic clusters of ecoregions that may span several habitat types, but have strong biogeographic affinities, particularly at taxonomic levels higher than the species level (genus, family)."

===Canadian Shield===
The [[Canadian Shield]] bioregion extends across the northern portion of the continent, from the [[Aleutian Islands]] to [[Newfoundland and Labrador|Newfoundland]]. It includes the Nearctic's [[Arctic Tundra|arctic tundra]] and [[boreal forest]] ecoregions.

In terms of [[floristic province]]s, it is represented by part of the Canadian Province of the [[Circumboreal Region]].

===Eastern North America===

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, savannas, and shrublands|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 province]]s, it is represented by the [[North American Atlantic Region]] and part of the Canadian Province of the [[Circumboreal Region]].

===Western North America===
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 [[West Coast of the United States|Pacific Coast]] and [[Northern California]] to the [[Rocky Mountains]] (known as the [[Cascadia (bioregion)|Cascadian bioregion]]), 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 province]]s, it is represented by the [[Rocky Mountain Floristic Region|Rocky Mountain region]].

===Northern Mexico===
The Northern Mexico bioregion includes the mild-winter to cold-winter deserts and xeric shrublands, warm temperate and subtropical pine and [[Madrean pine–oak woodlands|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 realm|Neotropical]] [[Trans-Mexican Volcanic Belt pine–oak forests|Trans-Mexican Volcanic Belt]].<ref>{{Cite web |title=Ecoregions 2017 © |url=https://ecoregions.appspot.com/ |access-date=2023-01-25 |website=ecoregions.appspot.com}}</ref> This region also includes the only [[Tropical and subtropical dry broadleaf forests|subtropical dry broadleaf forest]] in the Nearctic realm, the [[Sonoran–Sinaloan transition subtropical dry forest]].

In terms of [[floristic province]]s, it is represented by the [[Madrean Region]].