The 1.78 million-acre Coronado National Forest spreads across twelve widely scattered mountain ranges or "sky islands" that rise dramatically from the desert floor in southeastern Arizona and southwestern New Mexico. Sky Islands support an astonishing diversity of plant communities such as those one would encounter on a trip from Mexico to Canada. The Coronado is divided into five noncontiguous ranger districts each of which consists of several mountain ranges. Elevations range from 3,000 feet to 10,720 feet. The plant and wildlife communities of the Sky Islands are particularly susceptible to the effects of global warming: hotter, drier conditions drive animals—even plants—to seek cooler refuges, which in the Sky Islands means moving up a mountain. But as warming continues, even the tops of the Sky Islands will become too warm for many species.
