Madrean Sky Islands

The sky islands are the northernmost of the Madrean pine–oak woodlands, and are classified as part of the Sierra Madre Occidental pine–oak forests ecoregion, of the tropical and subtropical coniferous forests biome. The sky islands were isolated from one another and from the pine–oak woodlands of the Sierra Madre Occidental to the south by the warming and drying of the climate since the ice ages.

There are approximately 27 Madrean sky islands in the United States, and 15 in northern Mexico. The major Madrean sky island ranges in Arizona are the Baboquivari Mountains, Chiricahua Mountains, Huachuca Mountains, Pinaleño Mountains, Santa Catalina Mountains, Santa Rita Mountains and Whetstone Mountains. Similar sky island ranges include the Animas Mountains in New Mexico and the Guadalupe Mountains, Davis Mountains and Chisos Mountains in west Texas.

Significant urban areas located very close to the Madrean Sky Islands include Las Cruces, New Mexico, and Tucson, Arizona.

Fauna

Though formerly extirpated from the United States, the North American jaguar has returned to the area from northern Mexico in small numbers. One such jaguar is named El Jefe.