Kneeland Prairie Penny-cress

Thlaspi californicum

Description

The Kneeland Prairie penny-cress is a perennial herb that grows from 3-6 in (8-15 cm) tall, from a basal rosette of leaves. The margins of the basal leaves range from entire to toothed. The four-petaled, white flowers have strongly ascending pedicels (or stalks). The ripe fruit is a sharply pointed silicle (a short fruit typically less than two to three times longer than wide).

Habitat

The Kneeland Prairie penny-cress occurs in native coastal prairie on serpentine soil. Serpentine soil contains high concentrations of nickel and cobalt, and an imbalance of the nutrients magnesium and calcium, and is inhospitable to nonadapted plants. The rare penny-cress occurs at an elevation of about 2,500 ft (760 m).

Distribution

The Kneeland Prairie penny-cress is a locally evolved (or endemic) species that is found only in Humboldt County, California.

Threats

The Kneeland Prairie penny-cress is only known to exist at one location, near Kneeland Airport, about 11 mi (18 km) east of Eureka. This population of roughly 11,000 plants grows over an area of only 0.6 acre (0.25 hectare). The construction of the airport divided the pre-existing population of the rare plant into two adjacent ones, both located on privately owned land. It is estimated that the area of habitat in the year 2000 was only about 30-40% of that existing in 1967. The remaining habitat is at risk from proposed expansion of the airport, and potential road construction. In addition, the very small area of critical habitat and single population of the endangered species means that it is at inherent risk of extinction caused by a severe disturbance by wildfire, an event of severe weather, or some other catastrophe.

Conservation and Recovery

The private landowners of the critical habitat of the Kneeland Prairie penny-cress are aware of the presence of the rare plant and of its extremely limited habitat, as are the airport operators and others involved in management of the area. Conservation of this rare plant requires that its habitat be protected by land acquisition and establishment of an ecological reserve, or by negotiating conservation easements. The surviving population of the Kneeland Prairie penny-cress should be monitored. Research should be undertaken into the factors that are limiting its abundance, and of appropriate management practices to enhance the chances of its survival.

Contacts

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
Eastside Federal Complex
911 N. E. 11th Ave.
Portland, Oregon 97232-4181
Telephone: (503) 231-6121
http://pacific.fws.gov/

U. S. Fish and Wildlife Service
Sacramento Fish and Wildlife Office, Endangered Species Division
2800 Cottage Way, W-2605
Sacramento, California 95825-1846
Telephone: (916) 414-6600
Fax: (916) 460-4619

References

U. S. Fish and Wildlife Service. 12 February 1998. "Endangered and Threatened Wildlife and Plants: Proposed Endangered Status for the Plant Thlaspi californicum (Kneeland Prairie Penny-Cress) From Coastal Northern California." Federal Register 63 (29):68903-68984.

U. S. Fish and Wildlife Service. 9 February 2000. "Endangered and Threatened Wildlife and Plants: Determination of Endangered Status for the Plant Thlaspi californicum (Kneeland Prairie Penny-Cress) From Coastal Northern California." Federal Register 65 (27):6332-6338.

U. S. Fish and Wildlife Service. 2000. "Humboldt County Native Plant Gains Federal Protection." U. S. Fish and Wildife Service News Releases: Region 1. (http://www.r1.fws.gov/news/2000-28.htm). Date Accessed: July 6, 2000.