Cultural History
Native Peoples
Prehistoric desert people, wandered the upland canyons of the Ajo Range to gather wild foods and to drink from pools of water in the rock known as tinajas. When the Spanish arrived in the 16th century, descendants of these prehistoric peoples, the Tohono O'odham (formerly called the Papago), occupied this section of the Sonoran Desert and were engaged in dry farming.
Exploration & Settlement
During the next three centuries, Spanish, Mexicans and Americans greatly disturbed the natural habitat by cattle ranching and mining the desert of its precious metals. But in the last half century, since its establishment as a national monument, this unique region of the Sonoran area has begun to revert to its wilderness state.
Political History
The Monument was established by President Franklin Roosevelt on April 23, 1937.
Established as a Biosphere Reserve in 1976, it is an almost pristine example of the Sonoran Desert.
Acreage: 330,688.86
- Federal: 329,316.31;
- Non-federal: 1,372.55.
- Wilderness area: 312,600.
Natural History
Plants & Animals
Organ Pipe Cactus National Monument was established to protect the rare Organ Pipe Cactus and 26 other cacti species, as well as more than 200 species of birds and other animals, many of which are unique to this area. Three distinctive divisions of the Sonoroan Desert converge here, representing six plant communities. The uniqueness of this habitat is attested to by the rarity of the Organ Pipe Cactus itself, and the even more rare Senita Cactus, both of which are found nowhere else in the US.
Prevalent plants include: Buckhorn Cholla, Creosote Bush, Chain-fruit Cholla, Teddy Bear Cholla, Ocotillo, Bursage, Englemann's Prickly Pear, Barrel Cactus, Jojoba, Mexican Jumping Bean, Christmas, Cactus, Pencil Cholla, Palo Verde, Oak, Juniper, Ironwood and Mesquite trees.
There are six varieties of rattlesnakes, as well as Gila Monsters and scorpions here at Organ Pipe. These animals play an important role in the ecology of the desert and should not be harmed. The include the Roadrunner, Western Diamondback Rattlesnake, Red-tailed Hawk, Coyote, Cactus Wren, Javelina, Desert Tortoise, Gila Monster, Gila Woodpecker and White-winged Dove.
Geology
As elsewhere in southern Arizona, steep linear mountain ranges are separated by sloping desert plains melting into pediments. All the mountains in Organ Pipe are fault-block ranges of different age and rock types.
The Bates Mountains in the northwestern portion of the park are flat-topped, sharp-edge mesas topped with Quarternary basalt lava flows.
The Ajo Range and the northwest slope of the Puerto Blanco Range are rugged, eroded Tertiary volcanic rocks with tilted layers of tuff, lava and breccia. The Ajos are cut through with numerous igneous dikes.
The southern Puerto Blanco Mountains and those in the Senita Basin are rounded hills of Mesozoic granite.
The central portion of the Puerto Blanco Mountains are light-colored metamorphic schist and gneiss from the Mesozoic. In places they contain pegmatite dikes.
Organ Pipe Cactus NM Package - Book and Map to help explore the park.
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