Place

Ajo Mountain Drive Stop 1

A mature Organ Pipe Cactus stands amongst desert vegetation, with mountains in the background.
Welcome to the Sonoran Desert, the most diverse desert in North America.

NPS Photo/ Craig Stocks

Quick Facts
Location:
Mile 0 [km 0] along the Ajo Mountain Drive

Information Kiosk/Bulletin Board

Stop 1

The Sonoran Desert


Welcome to Organ Pipe Cactus National Monument, the heart of the Sonoran Desert. This desert covers 110,000 square miles (280,000 sq km), an area about the size of the state of New Mexico. The Sonoran Desert is the most diverse desert in North America, home to over 4,000 species of plants and animals. Why is this place so diverse? What makes this desert different from the Great Basin Desert to our north, Mojave to our west or the Chihuahuan to our east? Many factors make the Sonoran Desert unique. Our winters are mostly frost-free, and there are two rainfall periods, one in the winter/spring and another in July and August. The high mountain ranges affect how much rain falls in an area, creating a diversity of
habitats for specially adapted plants and animals to thrive. Everything seems to be related or connected to something else in complex ways.

Based on plant evidence, scientists believe this is a young desert, only about 10,000 years old, with its ancestry in the tropics. Many of our perennial plants (cacti and other succulents) and animals (such as lizards and snakes) migrated from the tropics or are descendants of tropical species. They prosper in the brief summer storms that occur here. Annual plants, like many wildflowers, rely on the soaking winter rains that help make the Sonoran Desert so diverse. Many plants and animals in the Sonoran Desert have adapted to reproduce or grow after sufficient rainfall in winter or summer. Most animals that live here are either nocturnal or crepuscular (dusk- or dawn-active) to thwart the high daytime temperatures. These adaptations, along with many more, allow the Sonoran Desert life to thrive.

Welcome to the Green Desert! As you travel down this road, we encourage you to travel slowly, pay attention to details, and discover some of these unique relationships for yourself.

 

Organ Pipe Cactus National Monument

Last updated: June 4, 2021