Zuni Fleabane

Erigeron rhizomatus

Description

Also commonly known as rhizome fleabane, the Zuni fleabane, Erigeron rhizomatus, is a perennial herb growing from a rhizome—an elongated, horizontal underground root. Clumps of slender, erect stems push up from the rhizome to a height of 10 to 16 in (25 to 45 cm) and display dark green, narrow leaves that are oblong to linear, and only about a 0.4 in (1 cm) long. The plant blooms from May to June, bearing small, single radial flowers with blue or white rays and yellow disks. Flowering stems are sparsely leafy, while sterile stems bear profuse leaves.

With Zuni fleabane, it is difficult to tell where one individual plant stops and another begins because each plant produces many stems from a single underground rhizome. New plants are rarely established by seed, although a large volume of seed is produced each year.

Habitat

Zuni fleabane grows on mid-elevation mountain slopes, restricted to a zone of red clays derived from the Chinle and Baca shales. Habitat elevation averages about 7,870 ft (2,400 m) and annual rainfall is 14 to 16 in (36 to 40 cm) per year. This plant prefers a northern exposure and takes root along the base of a slope where clay has crumbled to form a stratum of loose particles. Associated vegetation is pinyon-juniper woodland.

Distribution

The historic range for Zuni fleabane was probably throughout McKinley, Cibola, and Catron Counties, New Mexico, in localized areas of the Zuni Mountains, and the Datil and Sawtooth ranges.

About 20 populations are known from two widely separated localities in McKinley and Catron Counties: in the Cibola National Forest south of Fort Wingate (McKinley County); and in the Cibola National Forest and adjacent areas northwest of Datil (Catron County). All known populations occur on public lands, managed by the U.S. Forest Service or by the Bureau of Land Management (BLM). As recently as 1985, populations were considered stable, but no population figures were published. The species appears to be reproducing well, as plants of all age classes are represented.

Threats

The major threat to the Zuni fleabane is the potential for uranium mining in its habitat. The band of clays preferred by this species is geologically associated with underlying strata containing uranium ore. Many, if not all, known fleabane sites are encompassed by historic or active uranium mining claims. At present, a world glut in uranium has made development of the area unprofitable, but if uranium prices climb, these sites will become attractive to mineral development. Resumed mining activity would warrant upgrading the status of Zuni fleabane to Endangered.

Conservation and Recovery

Zuni fleabane is on the New Mexico State Endangered Plant Species List, which protects the plant from general molestation. The Forest Service and the BLM are required by law to consider the species when developing management plans for public lands under their jurisdiction. Whatever the future of uranium mining in the area, a portion of the Zuni fleabane's habitat will be set aside as a permanent preserve.

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

Martin, W. C., and C. R. Hutchins. 1981. A Flora of New Mexico. J. Cramer, Frankfurt, Germany.

Sabo, D. G. 1981. "Status Report: Erigeron rhizomatus." Office of Endangered Species, U.S. Fish and Wildlife Service, Albuquerque.

U.S. Fish and Wildlife Service. 1988. "Zuni Fleabane Recovery Plan." U.S. Fish and Wildlife Service, Albuquerque.