Madrean Archipelago

Madrean Archipelago

The western and southern edges of the Madrean Sky Island region are poorly defined and have received little study. Also known as the Sky Islands in the United States, this is a region of basins and ranges with medium to high local relief, typically 3,000 to 5,000 feet. Native vegetation in the region is mostly grama-tobosa shrub steppe in the basins and oak-juniper woodlands on the ranges, except at higher elevations where ponderosa pine is predominant. The region has ecological significance as both a barrier and bridge between two major cordilleras of North America: the Rocky Mountains and the Sierra Madre Occidental.

Flora:

Apachian Valleys and Low Hills: Sideoats grama, black grama, cane beard grass, plains love grass, blue grama, hairy grama, sand dropseed, vine mesquite, curly mesquite, false mesquite, Mormon-tea, mimosa, yucca, ocotillo, cacti, and agaves

The Lower Madrean Woodlands (generally above 5,000 feet): The Madrean encinal, evergreen oak woodlands, savannas, emory, silverleaf, Tourney, Arizona white oaks occur, piñon, juniper, mesquite, chaparral, cottonwood, sycamore, and willow

Madrean Pine-Oak and Mixed Conifer Forests: Ponderosa pine-oak forests, ponderosa pine forests, montane fir forests, and mixed conifer forests.