Scientific Name: Ranunculus californicus
Taxonomy Group: Vascular Plants
Range: British Columbia
Last COSEWIC Assessment: November 2008
Last COSEWIC Designation: Endangered
SARA Status: Schedule 1, Endangered
Image of California Buttercup
California Buttercup is a low, hairy perennial. The numerous stems are sprawling to erect and 15 to 50 cm long. The stems each generally have several shiny, lemon-yellow flowers in an open inflorescence. The flowers have up to 16 petals, unlike most species of buttercup, which typically have only 5 petals. During the spring, the species produces lobed basal leaves that are 2 to 8 cm long. This species is easily recognized by its showy, multi-petalled flowers. It is also readily distinguished from similar buttercup species, such as the Western Buttercup with which it hybridizes in British Columbia, by the curved beak on the dry fruits, or achenes.
Distribution and Population
California Buttercup is found along the west coast of North America, from southwestern British Columbia and the adjacent part of the state of Washington to Baja California where it is widespread. In British Columbia, it is restricted to two small island clusters that lie southeast of Victoria. Records from 2003 and 2005 indicate that there are four small confirmed California Buttercup populations in British Columbia and perhaps a fifth reported population on private land that could not be confirmed. There are believed to be between 3100 and 3600 individuals in these known populations. Searches throughout the British Columbian extent of potential occurrence have not resulted in any new populations of the species, although some sites adjacent to known populations appear to support hybrids. Given the lack of reliable long-term information on past population sizes of this species in Canada, current population trends are unknown. However, the amount of potential habitat has declined over the last century as a result of the partial development of coastal meadows for residential and recreational use. Because of limitations in seed dispersal, colonization and development of new populations is unlikely.
In Canada, California Buttercup is restricted to open coastal meadows on oceanic bluffs exposed to wind and salt spray on the southeast coast of Vancouver Island, which is characterized by mild, wet winters and cool, dry summers. It occurs in sites that remain open because of wind exposure along the shore, summer drought in thin soils, and winter seepage that waterlogs soils, preventing taller vegetation from dominating. California Buttercup is restricted to areas within 50 m of the coast, where frequent coastal fogs occur in the fall and winter and the climate is buffered against deep frosts in the winter.
Very little is known about the biology of this species. However, it is known that California Buttercup is normally a perennial species but sometimes acts as an annual in Canada. It is primarily bee-pollinated, although pollination may also be accomplished by thrips and flies. No specific information is known about seed dispersal in this species, but it is thought to be by adhesion to fur, feathers or clothing. Wind is also thought to contribute to seed dispersal for short distances. If California Buttercup is eaten by voles, as is the case with other buttercup species, its seeds could also germinate after passage through animal digestive systems and thus would be dispersed by the animal’s movement. However, since the species does not seem to be grazed by any herbivores in the islands and islets to which it is restricted, this mode of dispersal seems unlikely. Finally, California Buttercup is adapted to conserve moisture during the dry summer months.
Limitations for the California Buttercup populations in Canada are habitat loss through development, and alteration of habitat, particularly resulting from the invasion of sites by alien species. Extant populations of California Buttercup have generally been observed growing in a matrix dominated by many invasive alien species, which threaten them in various ways. First, shrubs and tall grasses shade out California Buttercup. Second, many grasses and forb species may outcompete California Buttercup for moisture and nutrients. Third, alien annual species prevent California Buttercup from colonizing suitable sites through their ability to pre-empt such sites. Perennial aliens may have established permanent cover in sites that formerly provided a constant supply of bare mineral soil. Another major threat to the species is recreational activities. A portion of one population occurs in the campground of a provincial marine park and has been mowed repeatedly. The balance of that population occurs in the immediate vicinity of a walking trail through the marine park. Although the other populations are located within reserves where recreational activities are prohibited, they are located in spots that are used nevertheless for recreation, particularly by picnickers who arrive by boat from Victoria. One of the populations occurs on an Indian reserve and could be placed at risk by the planned enlargement of communications towers. One other factor contributing to the decline of California Buttercup is fire suppression. Pre-European fire regimes in the dry coastal belt of southeast Vancouver Island killed young Red Alder and Douglas-fir and checked the growth of Trembling Aspen and most shrub species. The increase in light levels and decrease in competition resulting from fires favour low plants such as California Buttercup. In the absence of burning, the availability of suitable habitats has likely diminished.
Federal ProtectionThe California Buttercup is protected under the federal Species at Risk Act (SARA). More information about SARA, including how it protects individual species, is available in the Species at Risk Act: A Guide.
California Buttercup is not protected by any provincial legislation in British Columbia.
Provincial and Territorial Protection
Status of Recovery Planning
Recovery Strategies :
Name Recovery Strategy for the California Buttercup (Ranunculus californicus) in Canada
Status First posting on SAR registry
Garry Oak Ecosystems Recovery Team
Conan Webb - Chair/Contact - Parks Canada
Phone: 250-478-5153 Send Email
PLEASE NOTE: Not all COSEWIC reports are currently available on the SARA Public Registry. Most of the reports not yet available are status reports for species assessed by COSEWIC prior to May 2002. Other COSEWIC reports not yet available may include those species assessed as Extinct, Data Deficient or Not at Risk. In the meantime, they are available on request from the COSEWIC Secretariat.
8 record(s) found.
- COSEWIC Status Reports (1 record(s) found.)
- COSEWIC Assessments (1 record(s) found.)
- Response Statements (1 record(s) found.)
- Recovery Strategies (1 record(s) found.)
- Orders (2 record(s) found.)
- COSEWIC Annual Reports (1 record(s) found.)
- Consultation Documents (1 record(s) found.)
COSEWIC Status Reports
COSEWIC Annual Reports
COSEWIC Annual Report - 2009 (2009)2009 Annual Report to the The Minister of the Environment and the Canadian Endangered Species Conservation Council (CESCC) from the Committee on the Status of Endangered Wildlife in Canada.
- Date modified: