Sebastopol Meadowfoam

Limnanthes vinculans

Description

Sebastopol meadowfoam is an annual in the false mermaid (meadowfoam) family that grows to a mature height of about 12 in (30 cm). Its multiple stems bear long-stemmed, pinnately divided leaves comprising three to five leaflets. Single white flowers bloom at the ends of the stems.

Habitat

This species is limited to vernal pools and other seasonal wetlands in the Cotati Valley, California, which lies north of San Francisco. These pools occur where a non-porus material, such as clay, hard-pan, or volcanic stone, lies under surface depressions. In these areas, winter rains form pools which gradually dry out during the spring and summer. This unique habitat is not suitable for plant species that are intolerant of inundation or for aquatic species that require permanent standing water.

Sebastopol meadowfoam is found in Cotati Valley vernal pools along with two other endangered plants: Burke's goldfields (Lasthenia burkei) and Sonoma sunshine (Blennosperma bakeri). These species occur is an area of Sonoma County about 16 mi (26 km) long and 5-11 mi (8-18 km) wide. This range is bounded on the north by the town of Windsor; on the south by the town of Hessel; on the west by the Laguna de Santa Rosa, a tributary of the Russian River; and on the east by the foothills of the Sonoma and Mayacmas mountains. In the Cotati Valley, vernal pools form on Huichica loam and Clear Lake clay soil types where there is an impervious layer a few feet below the surface.

Other plants that grow in these vernal pools include fringed downingia (Downingia concolor), Navarretia spp. smooth lasthenia (Lasthenia glaberrima ), and Lobb's buttercup (Ranunculus lobbii ).

Distribution

Sebastopol meadowfoam was first described in 1969 from specimens collected in 1966 along Todd Road in Sonoma County. The species has never been recorded outside of the Cotati Valley.

At present there are 19 populations of Sebastopol meadowfoam in vernal pools in the southern portion of the Cotati Valley, Sonoma County. These scattered sites stretch from the vicinity of Santa Rosa south to Hessel. Most of the vernal pools are privately owned. One site, the Todd Road Reserve, is owned by the California Department of Fish and Game. It contains a population of Sebastopol mead-owfoam as well as the endangered Sonoma sunshine (Blennosperma bakeri). Four other sites are owned by county or city agencies.

Threats

The overwhelming threat to Sebastopol mead-owfoam and other vernal pool species is the destruction of these unique habitats for residential and agricultural development. So far about 90% of the Cotati Valley has been developed. The need for affordable housing within commuting distance of San Francisco has increased developmental pressure throughout the valley.

The construction of housing developments near Santa Rosa is destroying populations of Sebastopol meadowfoam, as well as Burke's goldfields (Lasthenia burkei) and Sonoma sunshine (Blennosperma bakeri). Recently, more than a dozen pools have been filled without the landowners obtaining permits from the Army Corps of Engineers as required by the federal Clean Water Act. In part because most of the pools are relatively small, the Corps of Engineers has been reluctant to examine the ecological effects of destroying these seasonal wetlands. Now that Sebastopol meadowfoam and other vernal pool species have been listed under the Endangered Species Act, the Corps is required to consult with the U. S. Fish and Wildlife Service whenever alteration of their wetland habitat is proposed, regardless of size.

Sebastopol meadowfoam faces an additional threat related to development. Santa Rosa is planning to expand its wastewater treatment facility to accommodate its growing population. Currently, treated wastewater is used to irrigate about 4,500 acres (1,821 hectares) of cropland. Expansion plans call for the construction of a series of terraces planted with water-tolerant grasses and flooded with waste-water for treatment. The water would then be recycled for irrigation. The plan calls for the wastewater capacity to be increased to irrigate 7,500 acres (3,035 hectares). Even if vernal pools were not directly flooded, the increase in residential and agricultural development, as well as the probable spread of the semi-aquatic grasses, would threaten Sebastopol meadowfoam and other vernal pool species.

A lesser threat to Sebastopol meadowfoam is livestock grazing, which has reduced populations of endemic vernal pool species at many of their historic sites.

Conservation and Recovery

The most crucial need for conservation of the Sebastopol meadowfoam is the protection of its critical habitat from residential and agricultural development. In particular, the illegal filling of vernal-pool habitat must be stopped. Most of the surviving habitat is privately owned and potentially threatened by various activities. This habitat should be protected by acquiring the land and designating ecological reserves, or by negotiating conservation easements with the landowners. The populations of the Sebastopol meadowfoam should be monitored, and research undertaken into its biology, habitat needs, and beneficial management practices.

Contacts

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

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

References

Brown, C., and S. K. Jain. 1977. "Rare Plant Status Report: Limnanthes vinculans." California Native Plant Society, Sacramento.

Holland, R. E 1976. "The Vegetation of Vernal Pools: a Survey." In Vernal Pools: their Ecology and Conservation, a symposium sponsored by the Institute of Ecology, University of California, Davis, May 1 and 2, 1976. Institute of Ecology Publication No. 9.

Jain, S. 1976. "Evolutionary Studies in the Meadowfoam Genus Limnanthes, an Overview." In Vernal Pools: their Ecology and Conservation, a symposium sponsored by the Institute of Ecology, University of California, Davis, May 1 and 2, 1976. Institute of Ecology Publication No. 9.

Ornduff, R. 1969. "Limnanthes vinculans, a New California Endemic." Brittonia 21:11-14.

Waaland, M. 1989. "Santa Rosa Plains Endangered Plant Protection Program Report, Section A." Sonoma County Planning Department and California Department of Fish and Game.

Wainright, T. C. 1984. "Status Report on Sebastopol Meadowfoam, Limnanthes vinculans Ornduff. U. S. Fish and Wildlife Service, Sacramento.