Eureka Valley Dune Grass

Swallenia alexandrae

Description

Eureka Valley dune grass, Swallenia alexandrae, is a coarse perennial with jointed stems, from 6-39 in (15-100 cm) tall, punctuated with stiff, lance-shaped leaf blades, 1-4.8 in (2.5-12 cm) long. Flowering stems develop large, grain-like flower heads, up to 4 in (10 cm) long.

This hardy grass forms large clumps at the base of a dune and spreads as sand stabilizes over and around it. When stems are buried, new stems root and grow from the leaf nodes. Most new growth occurs in February after the winter rains. Plants begin flowering in May. Seeds are dispersed by late June.

Habitat

Eureka Valley dune grass is found among active dunes and blowing sand along a valley that is dissected by washes and gullies that drain toward the southeast. Seasonal runoff turns the valley floor into a shallow, temporary lake. Habitat elevation ranges between 2,900-4,000 ft (900-1,200 m).

Clark's dicoria (Dicoria canescens ssp. clarkae ) is a common associate of this dune grass and is considered important in the overall dunes ecology. Many other plants in this region are noted for their singularity and are of particular scientific interest.

Distribution

This dune grass is endemic to the Eureka Valley Dunes of semi-arid eastern California.

Eureka Valley is situated 25 mi (40 km) east of Big Pine in Inyo County, California. The valley is bounded by the Inyo Mountains to the north and west, by the Saline Range to the south, and by the Last Chance Mountains to the east. Only four populations of this dune grass are known, all from southern Eureka Valley. The largest and most vigorous population is found on the massive north ridge of the Eureka Dunes. Other populations are found at Saline Spur Dunes, Marble Canyon, and south of Marble Canyon in an isolated sand deposit in the Saline Range.

Threats

Except for a few state-owned parcels, the entire Eureka Valley is federal land administered by the Bureau of Land Management (BLM). The relative inaccessibility of the valley served to protect the delicate dunes ecosystem for many years, but more recently the isolation has attracted campers, hikers, and off-road vehicle enthusiasts. In the 1960s, off-road vehicle traffic severely damaged the dunes. When portions of the Eureka Valley were classified as a Special Design Area in 1976, the dunes were officially closed to vehicles of any kind. Without this disturbance, the habitat has made a dramatic recovery.

Conservation and Recovery

The U. S. Fish and Wildlife Service Recovery Plan for this and the federally Endangered Eureka Valley evening-primrose (Oenothera avita ssp. eurekensis ) has a single, basic premise—to limit disturbance of the habitat. Left alone, the hardy dune grass will survive and reproduce. Therefore, the BLM is intent on strictly enforcing current restrictions on hiking, camping, and vehicular traffic in the valley. Camping and picnic sites will be made available but located away from sensitive dune borders and slopes.

Contact

Regional Office of Endangered Species
U.S. Fish and Wildlife Service
Eastside Federal Complex
911 N. E. 11th Ave.
Portland, Oregon 97232
http://pacific.fws.gov/

References

DeDecker, M. 1979. "Can BLM Protect the Dunes?"Fremontia 7:6-8.

Henry, M. A. 1979. "A Rare Grass on the Eureka Dunes." Fremontia 7:3-6.

Roll, L. A. 1979. "Can BLM Protect the Dunes?—A Reply." Fremontia 7:8.

U.S. Fish and Wildlife Service. 1982. "The Eureka Valley Dunes Recovery Plan." U.S. Fish and Wildlife Service, Portland.