Ute Ladies'-tresses

Spiranthes diluvialis

Description

Ute ladies'-tresses is a perennial orchid 8-20 in (20-50 cm) tall arising from tuberously thickened roots. The narrow leaves are about 11 in (28 cm) long at the base of the stem and become reduced in size going up the stem. The flowers consist of 3-15 small white or ivory colored flowers clustered into a spike arrangement at the top of the stem. The species is characterized by whitish, stout, flowers gapping at the mouth. The sepals and petals, except for the lip, are rather straight, although the lateral sepals are variably oriented, with these often spreading abruptly from the base of the flower.Sepals are sometimes free to the base. The lip lacks a dense cushion of trichomes on the upper surface near the apex. The rachis is sparsely to densely pubescent with the longest trichomes 0.008 in (0.02 cm) long or longer.

Ute ladies'-tresses generally flowers from late July through August, occasionally into September and early October.

Habitat

This species is a riparian species endemic to moist soils in mesic or wet meadows adjacent to springs, lakes, or perennial streams between the elevations of about 5,500-6,850 ft (1,676-2,087 m). Within these habitat types, Ute ladies'-tresses can be found in the more open areas that have not been heavily grazed. The two eastern populations occur in mesic riparian meadows in relict tall grass prairie areas in Colorado. The central populations of Ute ladies'-tresses are in wet or mesic riparian meadows or in understory meadows of riparian woodlands in eastern Utah. The western populations are found in riparian, lake and spring-fed wet or mesic meadows in western Utah and eastern Nevada.

Distribution

Ute ladies'-tresses is found in three separate geographic areas of the interior western United States.

There are two populations in Colorado; one on property owned by the City of Boulder, Boulder County, and the other along Clear Creek in Jefferson County. Historic collections may have been made from either Weld or Morgan County along the South Platte River Valley in 1856 and in El Paso County in 1896.

The second area is along the Colorado River drainage in eastern Utah. Populations are found along: Green River, Daggett County; Dinosaur National Monument's Cub Creek drainage, Uintah County; Uinta and Whiterocks Rivers, Duchesne and Uintah Counties; Duchesne River, Duchesne County; Fremont River in Capitol Reef National Park, Wayne County; Deer Creek, Garfield County. All of the eastern Utah populations were discovered after 1977.

The third area is in western Utah and eastern Nevada including: Utah Lake, Utah County; Weber County, Utah; Jordan River drainage, Salt Lake County, Utah; Red Butte Canyon near Salt Lake City (plants in this population were last observed in 1966); Tooele County, Utah (plants in this population were last observed in 1956); and Lincoln County, Nevada (plants in this population were last observed in 1936). Most of the Utah populations are on Bureau of Land Management (Vernal and Cedar City Districts), National Park Service (Dinosaur National Monument and Capitol Reef National Park), or U.S. Forest Service (possibly on Ashely, Dixie, Fishlake, Manti-Lasal, Uinta, and Wasatch-Cache National Forests) lands. One population is found on Ute Indian Tribal lands on the Uintah and Ouray Reservation. Two populations are found on private property.

Less than 6,000 individual plants of Ute ladies'-tresses are known (as of 1992) in the 10 remaining populations. The Boulder County population is the largest of the known populations. In 1986 this site contained 5,500 plants.

Threats

Modifications to and losses of riparian habitat have adversely affected Ute ladies'-tresses, especially along the Wasatch Mountain foothills in Utah. These areas have been affected by urbanization, stream channelization, and construction projects in and adjacent to the Jordan and Weber Rivers and their tributaries, and in wetlands and wet meadows adjacent to Utah Lake and the Great Salt Lake. All but two populations in western Utah and Nevada are believed to be extinct due to the above mentioned activities. The Colorado populations are threatened by the potential conversion of open space areas to developed parks. Most of the populations are in areas where they could be impacted by livestock grazing and trampling. The actual impacts of these activities on Ute ladies'-tresses are unknown. Intense grazing is thought to be detrimental but light to moderate grazing may actually be beneficial.

Localized catastrophic events could lead to the extinction of individual populations as could the indiscriminate use of herbicides or other chemicals.

All riparian plant species are vulnerable to alterations in stream flow and water table levels.

Conservation and Recovery

Recovery of Ute ladies'-tresses will depend on the protection and restoration of the riparian habitats inhabited by this plant. Studies are needed to determine this species' specific life history and ecological requirements, as well as how livestock grazing and other human related activities affect the plant. Propagation and transplant techniques should be developed and Ute ladies'-tresses should be introduced or reintroduced into areas with suitable habitat to establish new populations.

Contacts

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

Ecological Services Field Office
Lincoln Plaza
145 East 1300 South, Suite 404
Salt Lake City, Utah 84115

Reference

U.S. Fish and Wildlife Service. 17 January 1992. "Endangered and Threatened Wildlife and Plants; Final Rule to List the Plant Spiranthes diluvialis (Ute Ladies'-tresses) as a Threatened Species." Federal Register. 57(12): 2048-2053.