Branched phacelia (Phacelia ramosissima) COSEWIC assessment and status report: chapter 2

COSEWIC Executive Summary

Branched Phacelia
Phacelia ramosissima

Species information

Branched phacelia (Phacelia ramosissima)is a member of a genus of about 150 species, occurring mostly in western North America and Mexico. Eight of these species occur in British Columbia and 11 in Canada. Since only a single variety (var. ramosissima) is found in Canada the species is referred to simply as P. ramosissima in the report except where required for clarity to distinguish the species in Canada from variants in the United States.

Phacelia ramosissima is a prostrate to weakly ascending perennial herb from a branched stem-base and a taproot. The alternating leaves are 10-20 cm long, and 3-10 cm wide. The inflorescence is fiddlehead-shaped and consists of a cluster of lavender, pale cream, or sometimes white, corollas. The fruits are capsules that contain 8 to 12, 1-2 mm long, pitted seeds.

Distribution

Phacelia ramosissima occurs in western North America, from the southern Okanagan Valley in south-central British Columbia south through Washington and Oregon to Nevada and southern California. In British Columbia, Phacelia ramosissima has been collected or observed at 12 sites on the slopes of Mount Kruger, near Osoyoos, in the southern Okanagan Valley.

Habitat

Populations in British Columbia are found on the slopes of Mt. Kruger, in the Bunchgrass Biogeoclimatic Zone of southern British Columbia. This zone, particularly in the southern Okanagan Valley, has a cold, semi-arid steppe climate. The Bunchgrass Zone occupies less than one percent of the total area of British Columbia and is one of the most populated and developed areas in the B.C. interior. P. ramosissima is restricted, within this zone, to extremely dry talus slopes at the base of usually calcareous cliffs and rock outcrops.

Biology

There has been little research on the biology of Phacelia ramosissima. The species is a perennial that is well adapted to growing in areas with little precipitation. The plant is a heliotrope with its flowers turning to face the sun throughout the day.

Bees are known to be major pollinators of Phacelia ramosissima in California and are probably important in the southern Okanagan. Individuals of this species in British Columbia occur in close enough proximity for effective pollen transfer and the plants produce large amounts of seeds. Short-range dispersal is likely by small mammals or birds and in some cases by downslope movement of seeds. Long-range dispersal mechanisms remain unknown.

Although the habitat of this species receives little precipitation during the growing season, below-ground moisture is apparently sufficient for growth and reproduction. Highly specialized with respect to its habitat in Canada, Phacelia ramosissima occurs only on a narrow band of talus and rock debris below rock outcrops.

Population sizes and trends

Phacelia ramosissima has likely always been rare in British Columbia, since British Columbia is the northern extent of the species’ range. The total Phacelia ramosissima population consists of three separate populations, all on Mount Kruger in the southern Okanagan Valley in British Columbia comprising a total of fewer than 1000 plants. The area of occupancy is between 800 and 1000 m2. Two known subpopulations have been extirpated.

Limiting factors and threats

Phacelia ramosissima is limited to talus slopes in the southern Okanagan Valley in British Columbia. Significant threats to the population include mining and urban development.

Special significance of the species

Populations ofPhacelia ramosissima in British Columbia are unique in that they are at the northern extent of their geographic range. The species has been grown in the gardens of some native plant gardeners. In southern California, Aboriginal peoples used the leaves for food and the roots for the treatment of certain medical conditions.

Existing protection or other status designations

In Canada, Phacelia ramossisima has a rank of N2. Provincially, it is ranked as S2 (imperiled). There is currently no specific endangered species legislation in place for the protection of vascular plants in British Columbia that have been given this critical rank. One population and one subpopulation are protected by the Provincial Park Act.

COSEWIC History

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) was created in 1977 as a result of a recommendation at the Federal-Provincial Wildlife Conference held in 1976. It arose from the need for a single, official, scientifically sound, national listing of wildlife species at risk. In 1978, COSEWIC designated its first species and produced its first list of Canadian species at risk. Species designated at meetings of the full committee are added to the list.  On June 5, 2003, the Species at Risk Act (SARA) was proclaimed. SARA establishes COSEWIC as an advisory body ensuring that species will continue to be assessed under a rigorous and independent scientific process.

COSEWIC Mandate

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assesses the national status of wild species, subspecies, varieties, or other designatable units that are considered to be at risk in Canada. Designations are made on native species for the following taxonomic groups: mammals, birds, reptiles, amphibians, fishes, arthropods, molluscs, vascular plants, mosses, and lichens.

COSEWIC Membership

COSEWIC comprises members from each provincial and territorial government wildlife agency, four federal agencies (Canadian Wildlife Service, Parks Canada Agency, Department of Fisheries and Oceans, and the Federal Biodiversity Information Partnership, chaired by the Canadian Museum of Nature), three non-government members and the co-chairs of the species specialist and the Aboriginal Traditional Knowledge subcommittees. The Committee meets to consider status reports on candidate species.

Definitions (November 2004)

Wildlife Species

A species, subspecies, variety, or geographically or genetically distinct population of animal, plant or other organism, other than a bacterium or virus, that is wild by nature and it is either native to Canada or has extended its range into Canada without human intervention and has been present in Canada for at least 50 years.

Extinct (X)

A wildlife species that no longer exists.

Extirpated (XT)

A wildlife species no longer existing in the wild in Canada, but occurring elsewhere.

Endangered (E)

A wildlife species facing imminent extirpation or extinction.

Threatened (T)

A wildlife species likely to become endangered if limiting factors are not reversed.

Special Concern (SC) Footnotea

A wildlife species that may become a threatened or an endangered species because of a combination of biological characteristics and identified threats.

Not at Risk (NAR) Footnoteb

A wildlife species that has been evaluated and found to be not at risk of extinction given the current circumstances.

Data Deficient (DD) Footnotec

A wildlife species for which there is inadequate information to make a direct, or indirect, assessment of its risk of extinction.

 

Canadian Wildlife Service

The Canadian Wildlife Service, Environment Canada, provides full administrative and financial support to the COSEWIC Secretariat.

 

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