Seaside bone (Hypogymnia heterophylla) COSEWIC assessment and status report: chapter 2

Species information

Golden paintbrush has a chromosome count of 2n=24. Studies have shown that exceptionally high levels of genetic diversity are maintained within the species compared with other narrowly endemic plant species. The Trial Island population, though one of the most geographically isolated, was the most genetically diverse and showed relatively low levels of genetic divergence. In contrast, the Alpha Islet population showed the second highest level of genetic convergence but only middling levels of genetic diversity.

Distribution

The global distribution of the North American endemic species Hypogymnia heterophylla is along the Pacific coast from the southern tip of Vancouver Island in the north to Puget Sound in Washington and the outer Pacific coast south through Oregon and California to the Santa Barbara/Los Angeles/Channel Islands coastal regions. In Canada, H. heterophylla is known from four coastal locations at the southwest tip of Vancouver Island.

Habitat

Hypogymnia heterophylla is found in the driest sub-zone of the Coastal Western Hemlock biogeoclimatic zone.Locations where H. heterophylla occurs are typically coastal ledges at low elevation with high solar radiation, strong west-southwesterly winds, moderate precipitation and high humidity. Preferred habitat for H. heterophylla is coastal early to intermediate shore pine (Pinus contorta var. contorta) seaside stands. Marine aerosols from salt water spray may a be habitat requirements for this species.

Biology

Asexual reproduction in Hypogymnia heterophylla may occur by fragmentation of the lateral lobules that are perpendicular to the branch and by the production of conidiospores that act as asexual spores. Sexual reproduction in H. heterophylla must take place by the dispersal of sexually produced fungal ascospores that must capture compatible Trebouxia green algal cells before growth takes place.

Population sizes and trends

Ten subpopulations of Hypogymnia heterophylla were found at four locations on the southwest tip of Vancouver Island: East Sooke Regional Park, Bentinck Island and Sheringham Point. The total number of thalli estimated is likely greater than 1000. Lichen populations most likely remain stable in these locations.

Herbarium database searches at the University of British Columbia (UBC) and the British Columbia Conservation Data Centre (CDC) indicate no collection of H. heterophylla has been accessioned after 1996, indicating that recent non-targeted collections have not contained H. heterophylla or collections may not have been accessioned.

Limiting factors and threats

The primary factors limiting the dispersal and spread of Hypogymnia heterophylla are the necessity of early seral shore pine habitats located on rocky windswept ledges with southwest to western aspects. Damage caused by winter storms appears to be the major threat.

Special significance of the species

Hypogymnia heterophylla is an endemic species in North America and its restricted occurrence in Canada is at the northern limit of its range. This epiphytic species is restricted to the Pacific Northwest coastal areas of North America.

Existing protection or other status designations

Hypogymnia heterophylla was designated a species of Special Concern by COSEWIC in 1996. Parks and federally owned land protect the existing locations on the southwest tip of Vancouver Island where H. heterophylla is found. British Columbia ranks H. heterophylla as S1 indicating that occurrences are tracked. Washington (S3) tracks H. heterophylla while Oregon (SNR) and California (SNR) have not ranked this species.

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 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 (2007)

DEFINITIONS (2007)
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)* 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)** A wildlife species that has been evaluated and found to be not at risk of extinction given the current circumstances.
Data Deficient (DD)*** 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.
   
* 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. Definition of the (DD) category revised in 2006.
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Environment Canada

Canadian Wildlife Service

Environnement Canada

Service canadien de la faune

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

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