White meconella (Meconella oregana) COSEWIC assessment and status report: chapter 2

Executive Summary

White Meconella
Meconella oregana

Species information

Meconella oregana (white meconella) is a member of the poppy family (Papaveraceae) and the only species of the genus Meconella in Canada. It is a small annual herb, 2-16 cm tall with a slender taproot. Plants have either a single erect stem or stems that are sparingly branched near the base. The tiny, spoon-shaped leaves that form a rosette at the base of the plant are only 3-18 mm long, including their short stalks. The small stem leaves are opposite, lance-shaped to linear and lack stalks. Flowers are borne singly on long stalks at the end of the stems or from the upper leaf axils. Within the centre of the flower, consisting of six, white, egg-shaped petals and three sepals, are 4-6 stamens and a single pistil. The fruit is a linear capsule containing many tiny seeds less than 1 mm long. In the southwestern U.S. two other, slightly larger species occur (M. californica and M. denticulata) which were once described as subspecies of Meconella oregana.

Distribution

The global range of Meconella oregana extends from California to southern British Columbia. Within Canada it has been documented in low-elevation coastal areas from Victoria to Nanaimo, in the Gulf Islands, and in Port Alberni.

Habitat

In British Columbia, the plants grow on south-facing hillsides free of woody vegetation due to shallow and droughty soils that, however, are frequently subject to early-season seepage. Associated species are other small vascular plants and bryophytes.

Biology

The flowering period of Meconella oregana is between early March and mid-April and the plants set seed and dry off in early to later April, depending on weather conditions. Insect pollination has not been reported on and it is likely that wind pollination occurs. Germination under horticultural conditions has been reported both in fall and early spring. Herbivory of the plants has not been observed.

Population sizes and trends

The total population size of Meconella oregana in Canada was 3355 plants in 2004. The area of occupancy is only between 50 and 100 . Regular observations of population sizes and trends of Meconella over the years are not available for either the U.S. or Canada. In British Columbia 15 distinct populations are on record of which only five could still be confirmed as extant in the spring of 2004. Some of the records date back more than 100 years and seven of them have not been confirmed for 50 years. Population data for 2005 obtained subsequent to completion of the report and prior to designation have been added. These indicate that three of the four extant populations have suffered considerable declines since 2004.

Limiting factors and threats

The two major threats are habitat loss and habitat degradation. Habitat loss occurs primarily through residential development of the attractive open hillsides the species occupies. The two largest populations (75% of the Canadian total) are imminently threatened with such development. Habitat degradation occurs through recreational and other traffic, domestic grazing, disruption of seepage patterns, fire suppression and through the increasing colonization by non-native plant species. An intrinsic limitation for the species may be its poor dispersal ability.

Special significance of the species

It is the only species of the genus Meconella in Canada. No medicinal, ceremonial, or other human use is known for Meconella oregana.

Existing protection or other status designations

Based on 2004 counts, nearly 85% of Meconella plants were on private land, 11% were in a Regional Park, and just over 4% were on unprotected federal land.  Meconella oregana has no legal protection in Canada. It is a red-listed species in British Columbia with a rank of N1S1 (critically imperiled at the national and provincial level). Itis ranked S1 (critically imperiled) in California and Oregon and S2 (vulnerable to extirpation) in Washington.

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)

Species
Any indigenous species, subspecies, variety, or geographically defined population of wild fauna and flora.

Extinct (X)
A species that no longer exists.

Extirpated (XT)
A species no longer existing in the wild in Canada, but occurring elsewhere.

Endangered (E)
A species facing imminent extirpation or extinction.

Threatened (T)
A species likely to become endangered if limiting factors are not reversed.

Special Concern (SC) *
A species of special concern because of characteristics that make it particularly sensitive to human activities or natural events.

Not at Risk (NAR)**
A species that has been evaluated and found to be not at risk.

Data Deficient (DD)***
A species for which there is insufficient scientific information to support status designation.

* Formerly described as “Vulnerable” from 1990 to 1999, or “Rare” prior to 1990.
** Formerly described as “Not In Any Category”, or “No Designation Required.”
*** Formerly described as “Indeterminate” from 1994 to 1999 or “ISIBD” (insufficient scientific information on which to base a designation) prior to 1994.

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.

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

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