The Nearctic Realm: North America's Biogeographic Kingdom

The Nearctic is one of Earth's eight biogeographic realms, covering North America (Greenland, Canada, USA, Mexico to ~central plateau), Bermuda, and the Arctic Archipelago.

Boundaries

• North/West: Arctic Ocean.
• East: Atlantic Ocean.
• South: Neotropical realm (transition ~central Mexico).

Habitat Diversity

• Tundra: High Arctic, alpine.
• Boreal Forest (Taiga): Spruce, fir, pine — vast carbon store.
• Temperate Forests: Deciduous (East), coniferous (NW), mixed.
• Grasslands: Tallgrass (prairie), shortgrass (plains), palouse.
• Deserts: Mojave, Sonoran, Chihuahuan, Great Basin.
• Mediterranean: California chaparral.
• Subtropical: SE USA, Gulf Coast.

Climate Drivers

• Continentality (extreme seasons interior).
• Gulf of Mexico moisture → humidity, storms.
• Pacific currents → Mediterranean (CA) & marine (PNW).
• Arctic air masses → winter cold.
• Rain shadows (Rockies, Sierra, Cascades).

Iconic Flora

Conifers (Douglas fir, redwood, sequoia, pines), deciduous (oak, maple, beech, hickory), grasses (big bluestem, buffalo grass), cacti (saguaro, prickly pear), wildflowers.

Iconic Fauna

• Mammals: Bison, elk, moose, caribou, bears (grizzly, black, polar), wolves, cougar, bobcat, beaver, pronghorn, bighorn sheep.
• Birds: Bald eagle, wild turkey, sandhill crane, snow goose, woodpeckers, hummingbirds.
• Reptiles/Amphibians: Rattlesnakes, gila monster, alligator, salamanders.
• Fish: Salmon, trout, bass, catfish, sturgeon.

Conservation Status

Habitat loss, fragmentation, invasives, climate change threaten many endemics. Protected areas (Yellowstone, Banff, Wood Buffalo, etc.) and corridors (Yellowstone to Yukon) are critical.

The Nearctic: a continent of extremes, from polar ice to subtropical wetlands, united by evolutionary history.