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COSEWIC assessment and status report on the contorted-pod evening-primrose (Camissonia contorta) in Canada

Executive Summary

Contored-pod evening-primrose
Camissonia contorta

Species information

Contorted-pod evening-primrose (Camissonia contorta) is a distinct member of the Evening-primrose family. It is an diminutive, slender herb, up to 40 cm long, arising from a slender taproot. Its stem is wiry, usually branched, peeling below and often sprawling.  It bears small flowers with four yellow petals. Its fruits are small, twisted pods that contain several small seeds. The stems, leaves and capsules are often deep red, particularly in unshaded environments.

Distribution

Contorted-pod evening-primrose ranges from British Columbia to California, east to Idaho and western Nevada. In Canada, it is restricted to coastal areas along southeastern Vancouver Iisland and the adjacent Gulf Islands, an area of approximately 750 km². Within this area, the plants occupy seven small areas totaling about 8 ha.

Habitat

In Canada, it is restricted to semi-stable sandy flats and dunes no more than 15 m above sea level. Such habitats are naturally fragmented, but have become more so with the degradation of sandy coastal dunes habitats within its Canadian range.

Biology

Contorted-pod evening-primrose is a short-lived annual. Plants typically germinate from March to May, and flower in April or May and disperse seeds in May or June. Most plants die with the onset of the summer drought in June. In unusual years, with significant rainfall events during the summer, a small proportion of plants may survive until late summer or early autumn. These plants may show renewed vegetative growth, flowering and fruiting following major rainfall events.

The seeds of Ccontorted-pod evening-primrose lack any apparent adaptations to assist in long-distance dispersal. Most seeds likely remain in the immediate vicinity of the parent plant. The short distances of seed dispersal and the strong tendency towards self-pollination suggest that there is little potential for a rescue effect, even over short distances.

Population sizes and trends

There are seven extant populations and one extirpated population in Canada. Individual populations vary from 20 to 2,000 plants and the total Canadian population is estimated to consist of 3,500-4,500 mature plants. One population has recently disappeared and another has declined by an estimated 95%. Overall, the total Canadian population is estimated to have declined by  approximately 35% in recent years.

Limiting factors and threats

Five Several major factors threaten extant populations and potential habitat. The most serious threat is posed by habitat loss and altered sand dynamics. Rrecreational activities, particularly those associated with vehicle use and beach activitieson the remaining areas of suitable habitat that have,themselves, undergone losses over recent decadesare also a major threat. A number of exotic, invasive shrubs and herbs are severely altering the ability of sites to support the species. Six of the seven populations are so small that they face a moderate to serious threat of demographic collapse. Herbivory, apparently by introduced Eastern Cottontails, has had a light minor impact on several mature plants. It does not appear to pose a serious threat to the species.

Existing protection

In British Columbia, the only area of Canada where the species occurs, it has been ranked S1 (critically endangered). There is no provincial legislation protecting contorted-pod evening-primrose at the species level. None of the populations occur within provincially protected areas, but there is one very small population in a national park reserve. Two populations, one large (about 2,000 individuals) and one medium-sized (<1,000), occur in Capital Regional District Parks. They are protected by park policy; however there is considerable recreational activity even within the small areas occupied by these populations.

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 5th 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 entities (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 science members and the co-chairs of the species specialist subcommittees and the Aboriginal Traditional Knowledge subcommittee. The Committee meets to consider status reports on candidate species.

Definitions (2006)

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 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 category that applies when the available information is insufficient (a) to resolve a species’ eligibility for assessment or (b) to permit an assessment of the species’ risk of extinction.

 

Canadian Wildlife Service

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

 

Footnote a

Formerly described as “Vulnerable” from 1990 to 1999, or “Rare” prior to 1990.

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Footnote b

Formerly described as “Not In Any Category”, or “No Designation Required.”

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Footnote c

Formerly described as “Indeterminate” from 1994 to 1999 or “ISIBD” (insufficient scientific information on which to base a designation) prior to 1994. Definition of the (DD) category revised in 2006.

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