Chisos Mountain Hedgehog Cactus

Echinocereus chisoensis var. chisoensis

Description

Chisos Mountain hedgehog cactus, Echinocereus chisoensis var. chisoensis, measures 3-6 in (7.5-15 cm) tall and has deep green or blue-green stems. The spine cluster consists of 12-14 radial spines and one to four white central spines. From March to early June, plants are conspicuous because of showy tri-colored flowers. Petals are red at the base, white at mid-length, and fuschia at the tips. Red-tinged, fleshy green fruits, covered with long white wool and bristles, mature between May and August. Each fruit contains 200-250 seeds.

Habitat

Chisos Mountain hedgehog cactus occurs on alluvial flats beside the Rio Grande River and smaller tributaries. It occurs at the base of mountain ridges at elevations of 1,050-2,390 ft (595-717 m). Ground cover in the area is sparse, estimated at 20-30%. The cactus is typically found on bare soil, within spreading clumps of Opuntia schottii, or in the shade of other associated plants.

Distribution

This cactus is endemic to flats and lower slopes of the southern Chisos Mountains in the Texas Big Bend Region. Botanists speculate that it was once more widespread in the region, because plants do not now occupy all available habitat within the current range. Surveys of the Mexican states of Chihuahua and Coahuila in 1982 did not locate any plants even though the habitat there is similar.

Only 11 small populations are known, all found within a small area—about 30 sq mi (77.7 sq km)— in the Big Bend National Park in Brewster County. Surveys conducted in 1986 and 1987 produced counts of only 183 plants, even though estimates in the early 1980s suggested a total population of about 1,000. The species 1993 recovery plan estimated that fewer than 1,000 plants remained, though it noted that a recent reconnaissance survey of the park located only a few dozen plants in visits to known sites, leading to the conclusion that the plants are very rare even within all of their known sites. Based on this and other surveys, the recovery plan noted that the plant had suffered a reduction in its geographical area of distribution and in the size and number of its populations. Many of the populations, especially those accessible to roadways, have been noted to be in decline.

Threats

Long-term climatic change—principally the region's desertification beginning some 5,000 years ago—may have contributed to the overall decline of Chisos Mountain hedgehog cactus. In spite of this decline, the cactus was still locally abundant in the early twentieth century, until the region was heavily used for cattle grazing. Cattle almost entirely eliminated the plant.

The species is presently threatened by its low numbers and narrow distribution. Plants growing next to a road have shown evidence of being collected casually by park visitors. The cactus is especially vulnerable to collectors during flowering when it is highly visible. During extended dry periods of the late 1980s Big Bend National Park personnel also noted damage to the plants from some kind of mammal predation, probably rodents or jackrabbits. Natural changes in climatic conditions, tending toward dryness, may also be adversely affecting the plant's reproduction. Catastrophic events such as fires, freezes and droughts could have potentially lethal effects on the existing populations, because of the plant's extremely limited distribution.

Conservation and Recovery

With the establishment of the Big Bend National Park, livestock grazing was suspended, and the gradual recovery of overgrazed rangeland may assist the plant's reestablishment. An effort to propagate seedlings for transplanting to suitable sites will figure prominently in recovery of this species. Unfortunately, low population viability may be limiting recovery.

But early cultivation experiments have been effective. In cooperation with the National Park Service, Sul Ross State University and the Chihuahuan Desert Research Institute have experimented with cultivating the cactus from cuttings and seeds, reporting in 1992 that they had grown more than 300 plants, though most were cloned from only a few individuals. This promising cultivation work has shown the potential for establishing a seed bank and cultivated collection. The Center for Plant Conservation (CPC) is also working with the National Seed Storage Laboratory in Fort Collins, Colorado, and the Desert Botanical Garden in Phoenix, to implement cultivation initiatives.

In 1990, the U.S. Fish and Wildlife Service (FWS) gave the species a recovery rating of 9 (on a scale of 1-18, with 1 being given the highest recovery priority). The 9 rating indicates that this is a plant variety with a moderate degree of threat and a high recovery potential.

The 1993 recovery plan for this species, from the FWS, calls for a goal of delisting by 2009. The species will be considered delisted when 50 distinct populations, each consisting of at least 100 reproductive individuals, have been established; and when it can be demonstrated that the populations are demographically stable and reproductively successful over a 10-year monitoring period.

Among the needed actions called for in the plan are the protection of present and newly discovered populations; the establishment of a reserve germ bank/cultivated population; the search for additional populations; and the development of a public education program. The plan also calls for research into successful management and restoration, and the assessment of restoration feasibility and establishment of a pilot reintroduction program.

Contact

Regional Office of Endangered Species
U.S. Fish and Wildlife Service
P.O. Box 1306
Albuquerque, New Mexico 87103
http://southwest.fws.gov/

References

Benson, L. 1982. The Cacti of the United States and Canada. Stanford University Press, Stanford, California.

Evans, D. B. 1986. "Survey of Chisos PitayaEchinocereus reichenbachii var. chisoensis. " Report. U.S. National Park Service, Big Bend National Park, Texas.

Heil, K. D., and E. F. Anderson. 1982. "Status Report on Echinocereus chisoensis." U.S. Fish and Wildlife Service, Office of Endangered Species, Albuquerque.

Heil, K. D., S. Brock, and J. M. Porter, 1985, "TheRare and Sensitive Cacti of Big Bend National Park." U.S. National Park Service, Big Bend National Park, Texas.

Taylor, N. P. 1985. The Genus Echinocereus. TimberPress, Portland, Oregon.

U.S. Fish and Wildlife Service. 1993. "Chisos Mountain Hedgehog Cactus Recovery Plan." U.S. Fish and Wildlife Service, Albuquerque.

U.S. Fish and Wildlife Service. 1988. "Determination of Threatened Status for Echinocereus chisoensis var. chisoensis." Federal Register. 53(190): 38453-38456.