Desert Abundance
The Santa Cruz Valley is a unique natural environment with mountain ranges scattered throughout desert grasslands, a desert river and its streams serving as ribbons of life, and rich biological diversity that serves as a critical route for migrating birds. This natural heritage shaped human settlement throughout the region.
The interpretive themes of the Santa Cruz Valley National Heritage Area that highlight the region’s rich biological diversity and natural heritage include the Sonoran Desert, Sky Islands & Desert Seas, Streams in the Desert, and Bird Habitats and Migration Corridors.
Saguaro National Park is in the SCVNHA. Its two sections are on east and west sides of the city of Tucson. The park is named for the large saguaro cactus, native to this desert environment. Photo courtesy Visit Tucson.
Sonoran Desert
The Sonoran Desert and its Arizona Uplands have the greatest diversity of plants of any desert in the world. It extends from the Santa Cruz Valley west into California and south along the Gulf of California into the state of Sonora Mexico. The natural habitat of the iconic saguaro cactus is exclusive to the Sonoran Desert.
Photo Courtesy of Visit Tucson.
Sky Islands and Desert Seas
Southeastern Arizona, southwestern New Mexico, northwestern Chihuahua, and northeastern Sonora are a landscape of wonder, beauty, wildness, and astounding biological diversity. This is the “Sky Island” region and Santa Cruz Valley National Heritage Area is its heart.
The southwestern Sky Island “archipelago” is unique on the planet and is the only Sky Island complex extending from subtropical to temperate latitudes with a globally unprecedented array of plant and animal species of northern and southern origins. These mountain islands are among the most diverse ecosystems in North America due to their great topographic relief and location at the meeting point of major desert and forest biomes.
Sky Islands are forested mountain ranges isolated from each other by intervening basins and valleys of desert and grassland, usually below 4,000 feet in elevation. The 40 ranges of the Sky Island system may be thought of as an “archipelago” connecting the “continents” of the Sierra Madre Mountain Range of northern Mexico to the south with the Rocky Mountains of the United States to the north.
A number of tropical and subtropical species inhabit this region, including the jaguar, coatimundi, Mexican long-tongued bat, elegant trogon, violet-crowned hummingbird, and banded rock rattlesnake. Eighteen species of bats, more than 400 species of birds, and about 100 species of butterflies can be seen here. Herds of the rare desert bighorn sheep survive in the most rugged and remote terrain. This is also one of the few places in the world where the saguaro cactus grows.
The Santa Cruz Valley is the only place in the United States where tourists can visit the sky islands and desert seas landscape and enjoy the exceptional scenic views and biological complexity in a National Heritage Area.
To learn more about the Sky Islands and Desert Seas read more here.
Streams in the Desert
The Santa Cruz River is a natural treasure for three nations: United States, Tohono O’odham, and Mexico. The river is nationally unique in that it originates in the U.S., crosses into Mexico, and returns to the U.S. Rising in the San Rafael Valley of southern Arizona, it crosses south into Sonora, Mexico, then turns north to reenter the U.S. east of Nogales. It continues north to cross about a 10-mile stretch of the San Xavier District of the Tohono O’odham Nation, through Tucson, and then north-northwest to the Gila River west of Phoenix.
Riparian areas along the banks of the Santa Cruz River and its perennial tributaries are home to special plants and animals, and are corridors for wildlife movements and migrations. These oases are habitats and migration stopovers for many bird species.
In the Santa Cruz River watershed there are 90 miles of streams and rivers that flow year-round, supporting riparian habitats—on the banks of streams and rivers—that are both beautiful and integral to life in the desert. At lower elevations, riparian habitats are dominated by willow and cottonwood trees. At higher elevations, these are joined by hackberry, sycamore, ash, walnut, alder and other trees. Some 60 to 75 percent of all wildlife in this region depend on riparian areas at some point in their lives, and 90 percent of all bird species are found in these desert oases.
To learn more about Streams in the Desert read more here.
Bird Habitats and Migration Corridors
Because of the area’s range of elevations and habitat types, a diversity of birds can be found here. These include species that people come here especially to see, such as the elegant trogon, common black-hawk, northern beardless tyrannulet, broad-billed hummingbird, Montezuma quail, and buff-breasted flycatcher. Of the 36 species of raptors (birds of prey) that nest in Arizona, 31 do so in the Santa Cruz River watershed. The valley is also a major migration corridor for species that winter in the tropics and nest north of the Mexican border. The Santa Cruz Valley has 21 of the 50 stops on the Southeastern Arizona Birding Trail.
Read more about Bird Habitats here.
