Get Involved You can learn more and explore new places when you join the Conservancy’s online community and build your own personalized nature page.   Housing development on the outskirts of Tucson spreads across the desert floor. Enlarge this photo "The Sonoran Desert is both the hottest and most tropical desert in North America." Go Deeper The  Sonoran Desert Ecoregion Learn more about this amazing landscape — which hosts wildlife from roadrunners to bighorn sheep to plant species that date back to the Ice Age. Namibia’s Kunene Region This region represents one of the last true wildernesses in Africa—and a rare opportunity to conserve a vast desert ecosystem and enhance its people’s quality of life

The Sonoran Desert is both the hottest and most tropical desert in North America. Forests of giant saguaro cactus salute night-blooming wildflowers in the Sonoran. The distinctive sound of rattlesnakes warns visitors that this is harsh terrain.

Yet this landscape is much more than dry, cracked ground and prickly plants:

• The Sonoran Desert is a 55-million-acre world of rugged mountain ranges, ancient lava flows, rivers, underground springs and sprawling sand dunes.
• About 200 imperiled species and many plants, reptiles and fish found nowhere else on Earth live here—such as the javelina, the only wild, native pig-like animal in North America.

Unfortunately, growing human populations within the ecoregion—along with invasive species and diminishing water resources—are threatening the fragile balance of this desert, which stretches from southeastern California through southern Arizona, Baja California and the Mexican state of Sonora.

That's why The Nature Conservancy is working with Mexican and U.S. government officials as well as private landowners and other partners to preserve the Sonoran. The work of the Conservancy and its partners in the desert includes:

• Identifying at-risk species like the desert tortoise, the nomadic Sonoran pronghorn and the saguaro cactus; 
• Attacking such invasive plant species as tamarisk (also known as salt cedar);
• Doing prescribed burns;
• Developing funds for conservation easements; and
• Bringing private landowners on both sides of the border together into networks that preserve biodiversity on their lands while also allowing hunting and ecotourism.     

Ideal Conditions for Unique Species

Although a dry and unforgiving landscape for much of the year, summer monsoons from the Gulf of Mexico and winter storms off the Pacific Ocean provide much-needed moisture in the cooler months and give the desert its tropical status.

Average yearly rainfall rarely exceeds a parched 12 inches. However, that's enough moisture to renew the springtime spectacle of flourishing wildflowers on the desert’s western edge, a major attraction for visitors and the javelina, which munches on the abundance of blooms and berries.

These unusual rainfall and moisture patterns—coupled with the intense heat—create ideal conditions for unique species adaptations, marking the Sonoran as a place that supports a broad diversity of life despite intense heat and extreme aridity:

• Singular reptiles, mammals and birds from the Gila monster to the Gila woodpecker and from the kangaroo rat to the roadrunner call the Sonoran home.
• Mesquite trees and some other plants here can die entirely above ground in order to preserve their root systems and rejuvenate with the next rainfall, helping them survive for as long as two centuries.
• Lupines and poppies typical of the Pacific west have migrated here and mingle with southwestern catclaw and creosote bush. 
• Other plants in this rare climate include the poisonous jimson weed, iconic tumbleweed, devil’s claw, ghost flower, and several cactus varieties, including hedgehog and Christmas cactus.

Working Across Borders to Ensure Ecosystem Health

Human influence is nothing new in the Sonoran. The desert contains significant archaeological sites, remnants of ghost towns and abandoned mines. But today, the Sonoran's biodiversity is under siege. From 1970 to 1990, the region's human population nearly doubled, to 6.9 million—and by 2020, the population is expected to reach 12 million.

As human population grows, native habitat is converted, scarce water resources are increasingly apportioned to human uses, and other growth-related impacts strain the viability of the region’s biodiversity.

Since much of the Sonoran Desert ecoregion is publicly owned, the Conservancy is working in collaboration with Mexican officials and the U.S. Bureau of Land Management to ensure adequate protection for these lands.

We are working with these officials to identify at-risk species and improve the health of their habitats. And we're developing guidelines for biodiversity management and protection with our federal partners.

Our collaboration with private landowners is also having an impact on conservation. In Mexico, the Conservancy is working with landowners to develop ecological management units, a federal land designation that allows people to operate their lands for hunting, ecotourism or conservation purposes.

And we are working to tackle invasive species issues across various jurisdictions to abate these and other threats to native plants and animals.

Benefits of National Monument Status

In 2001, a portion of the Sonoran Desert achieved National Monument status—which allows 496,000 acres within this rare ecoregion to be conserved permanently. The Conservancy's scientific analysis of conservation priorities for the Sonoran played a significant part in this designation.

Through community-based, cross-cultural and cross-national partnerships, monument status affords the Sonoran Desert and its many plants and animals a higher level of protection and preservation. After Death Valley, the Sonoran Desert National Monument is the largest U.S. national park and preserve south of Alaska.

Nature picture credits (top to bottom, left to right): Photos © Charlie Ott (Sonoran Desert); © Mark Godfrey/TNC (Rattlesnake); © Chris Helzer/TNC (Pima Canyon)