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Madrean Sky Islands Montane Forests (Sierra Madre Occidental Pine-Oak Forests)  (WWF ecoregion NA0302)

Madera Canyon, southeastern Arizona
Madera Canyon, southeastern Arizona

Source of bioregions data: Olson, D. M. and E. Dinerstein. The Global 200: Priority ecoregions for global conservation. (PDF file) Annals of the Missouri Botanical Garden 89:125-126.

Distinctiveness (1=highest,4=lowest): 1 (globally outstanding)
In the United States, this ecoregion is an archipelago of mountaintops surrounded by xeric grass and shrublands.  The dynamic history and isolation of the forested peaks has produced unusual evolutionary phenomena.  Mixing of suptropical and temperate organisms has also created unusual ecological assemblages.  The Madrean Sky Islands in the U.S. are a northern extension of the Mexican Sierra Madre Occidental mountain system.*

Conservation Status (1=most endangered, 5=most intact): 4 (relatively stable in U.S.)
Overgrazing, recreational pressure, military use, and development are threats.  In Mexico, much of the forests have been cleared through logging and agriculture.*

Characteristic species*
Pinus leiophylla var. chihuahuana (Chihuahuan pine)
Pinus cembroides (Mexican pinyon)
Pinus arizonica var. arizonica (Arizona pine)
Quercus hypoleucoides (silverleaf oak)
Quercus arizonica (Arizona white oak)
Quercus emoryi (Emory oak)
Quercus rugosa (netleaf oak)

Juniperus deppeana (alligator juniper)

Arctostaphylos pungens (pointleaf manzanita)
(c) 2004 Maurice J. Kaurmann

Some Arizona plants


Some views from the ecoregion

Madera Canyon, southeastern Arizona

Transition to shrubland on lower slopes hires

Oak-pine woodland vegetation hires

Pinus engelmannii (Apache pine) hires

Platanus wrightii (Arizona sycamore) hires

Arbutus arizonica (Arizona madrone) hires

* Ricketts, T.H., E. Dinerstein, D.M. Olson, C.J. Loucks, et al.  (1999) Terrestrial Ecoregions of North America: A Conservation Assessment.  World Wildlife Fund - United States and Canada.  Island Press, Washington, D.C. pp. 258-260.

Except as noted, images copyright 2002-2004 Steve Baskauf - Terms of use