The four deserts that sprawl across the southwest corner of the United States and into Mexico are a sight to behold.

Tall, twisted Joshua trees speckle the dry landscape. A series of mountain ranges emerge like islands from an ocean of flat plains. The jaw-dropping Grand Canyon slices through the Colorado plateau.

From the Mojave and Colorado deserts in the U.S. to the Chihuahuan and Sonoran and Baja Californian, these North American deserts are more biologically rich and diverse than any desert region in the world. Species here are also packed into an arid area smaller than most: Taken together, these deserts are only 13 percent the size of the African Sahara.

This relatively concentrated region is home to several Native American and Mexican communities that have long lived according to customs and traditions centered upon a deep respect for a healthy landscape. It is also home to nearly 6,000 vascular plant species, more than half of which live only here. Because they’re in good shape, Wilderness Areas like the North American Deserts help the broader environment function well, whether by regulating climate or harboring watersheds.

In the middle of the Mojave, Death Valley National Park is the largest protected area in the continental United States. It’s no coincidence that Mexico’s first protected areas were also created in these deserts. But while we celebrate this region’s health, we know it’s a challenge to keep it that way. The Mojave’s Lake Mead is a stark example. Pumped out of the desert to meet people’s demands for water in Las Vegas and Southern California, Lake Mead is shrinking by the day.