San Rafael Cactus

Pediocactus despainii

Description

San Rafael cactus, Pediocactus despainii, is a dwarf barrel-type cactus with stems up to 2.3 in (6 cm) tall and 4 in (10 cm) wide. Spine clusters (areoles), composed of nine to 13 white, flattened radial spines, partially obscure the stem. Central spines are absent. Flowers, about 1 in (2.5 cm) across, are peach to yellow with a bronze tint.

This cactus is distinguished from other closely related members of its genus by its larger stem size and the bronze tint of its flowers. Buds form in the fall at ground level and overwinter to blossom in spring.

Habitat

San Rafael cactus grows on hills, benches, and flats of the Colorado Plateau's semi-arid grasslands, a savannah-like habitat characterized by scattered junipers, pinyon pines, low shrubs, and hardy herbs.

Distribution

The genus Pediocactus comprises eight rare species that are derived from a parent genus that was widely distributed throughout Arizona, Colorado, New Mexico, and Utah, thousands of years ago. Four members of the genus—Brady pincushion cactus (P. bradyi ), Knowlton cactus (P. knowltonii ), Peebles Navajo cactus (P. peeblesianus var. peeblesianus ), and Siler pincushion cactus (P. sileri )—are federally listed as endangered. The remaining relatives—P. paradinei, P. peeblesianus var. fickeiseniae, and P. winkleri —are currently being considered for listing under the Endangered Species Act.

This species has been found in Emery County, Utah, and grows in two populations about 25 mi (40 km) apart. Each population contains 2,000-3,000 individual plants.

Threats

Collectors pose the greatest threat to the San Rafael cactus. Since the plant is very rare, it is eagerly sought by collectors in the United States and abroad. Commercial collectors are known to "make the rounds" of the Four Corners to collect complete sets of Pediocacti. This activity is illegal under U. S. and international statutes.

One concentration of San Rafael cacti is adjacent to a popular camping area, which attracts many hikers and recreational off-road vehicles. Many plants there have been trampled underfoot or crushed by vehicles. Although the cactus' stems recede into the ground during the dry season, ground disturbance can destroy the delicate buds that overwinter at the surface, limiting the plant's reproduction.

Conservation and Recovery

Roughly half of the surviving cacti occur on Bureau of Land Management (BLM) lands that have been leased for oil, gas, and mineral exploration. Although these claims are not being actively developed, mineral companies are required to conduct annual assessments of their claims to retain their permits. Assessment activities, including scraping, drilling, and use of explosives, continue to disturb the habitat and destroy plants.

Since this cactus was listed, the BLM has undertaken a review of its process of granting land-use permits where activities may damage cacti populations. Annual surveys of the sites are conducted by U.S. Fish and Wildlife Service botanists.

Contact

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
P. O. Box 25486
Denver Federal Center
Denver, Colorado 80225
http://www.r6.fws.gov/

References

Heil, K., B. Armstrong, and D. Schleser. 1981. "AReview of the Genus Pediocactus." Cactus & Succulent Journal 53:17-39.

U. S. Fish and Wildlife Service. 1987. "Determination of Endangered Status for Pediocactus despaini (San Rafael Cactus)." Federal Register 52(179): 34914-34917.

Welsh, S. L., and S. Goodrich. 1980. "Miscellaneous Plant Novelties from Alaska, Nevada, and Utah." Great Basin Naturalist 40:78-88.