Islands in the Sky

THE SKY ISLANDS ARE USUALLY MUCH COOLER AND MORE LUSH THAN THE DESERTS OR GRASSLANDS BELOW, BUT CLIMATE CHANGE IS UPENDING LIFE HERE.

- Charles C. Hofer

In Western North America, two massive mountain ranges dominate the region. To the north are the Rocky Mountains that extend from Alaska to New Mexico. To the south are the Sierra Madre Occidental, a towering range that makes up the backbone of Mexico. Connecting these two different worlds is a scattered network of small mountain peaks that rise from vast oceans of desert and grasslands. These are the Sky Islands, one of the most biodiverse regions on the planet.

Spanning southern Arizona and northern Mexico, the Sky Islands are home to 450 bird species-nearly half of North America's bird species-along with more than 3,500 species of plants. More than 100 species of reptiles and amphibians and a similar number of species of mammals live in the Sky Islands. These mountains are also a global hotspot for bee and ant diversity.

The Sky Islands are important for more than their stunning biodiversity. These isolated mountains are also a living laboratory for scientists. The Sky Islands are helping scientists understand how plants and animals will adapt to climate change and how we can help. 

Two Worlds