Macoun’s meadowfoam (Limnanthes macounii) COSEWIC assessment and status report: chapter 2

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Executive Summary

Species information

Macoun’s meadowfoam (Limnanthes macounii) is an annual species whose reclining stems with upturned tips arise from a fibrous root system. Its alternate leaves are pinnately divided. The inconspicuous white flowers have four sepals and petals and eight stamens; the pistil is four-lobed with the style having four stigmas. The fruit consists of up to four nutlets.

The species is endemic to southern Vancouver Island and several adjacent islands. It is the only native species of the genus Limnanthes in Canada and, with False Mermaidweed, Floerkea proserpinacoides, one of two Canadian representatives of the family Limnanthaceae.

Macoun’s Meadowfoam is unique in the family by having floral parts in multiples of four, whereas all other species of meadowfoam (Limnanthes) have floral parts in multiples of five.

Distribution

Macoun’s meadowfoam is known only from southern Vancouver Island and several other islands close to Vancouver Island. It has not been found on the mainland of British Columbia nor in Washington State.

In 1998, a large population of a plant originally identified as Macoun’s meadowfoam was found in California in a cabbage field, but so far it has not been found in natural habitats. Californian plants differ from those in British Columbia in a number of features and likely represent an undescribed species.

Habitat

Plants occur in seasonally wet depressions or along intermittent seeps in low elevations and usually close to the ocean. The majority of the sites are in open areas of Garry oak ecosystems.

Biology

Macoun’s meadowfoam is a winter annual. It germinates in the fall after the first heavy rains and grows throughout the winter. It flowers in March and April. The ovary develops into a maximum of four nutlets that are shed by the beginning of June. At that time, the plants wither and die.

Population sizes and trends

Macoun’s meadowfoam is now known from 28 extant populations. The original1988 status report listed 52 “populations” many of which should be treated as mere subpopulations. Applying the present concept of populations, the original 1988 COSEWIC report would have consisted of 24 populations. Four populations known in 1988 have been destroyed and seven previously overlooked populations have been found.

Of the 52 occurrences that were reported in the 1988 COSEWIC report (as “populations”), 29% (15) disappeared, 27% (14) declined, 19% (10) remained about the same and 23% (12) increased.

Limiting factors and threats

Macoun’s meadowfoam requires sufficient moisture in winter months and open soil. Threats include human activities and competition from introduced perennial grasses.

Special significance of the species

Macoun’s meadowfoam is a species endemic to British Columbia.

Existing protection

In 1988, Macoun’s meadowfoam was designated as vulnerable by the Committee on the Status of Endangered Wildlife in Canada (changed to Special Concern in 1999). In British Columbia, the Conservation Data Centre includes this species on its tracking list, as a BLUE-listed species.

Macoun's meadowfoam grows in areas with various legal protections. One site is a part of an ecological reserve (with one subpopulation legally excluded from the reserve, but managed as being a part of it). Two populations (7 sub-populations) are in provincial parks, three are in regional parks and three populations (8 sub-populations) are in municipal parks. Three large populations (27 sub-populations) occur in Department of National Defence (DND) lands, four (17 sub-populations) on Indian Reserves and eight (25 sub-populations) on private lands.

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.