Gold-edged gem (Schinia avemensis) COSEWIC assessment and status report: chapter 2

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Executive Summary

Species information

The Gold-edged Gem is a small (has a 16-20 mm wingspan), day-flying, noctuid (cutworm or owlet) moth in the subfamily Heliothinae (Flower Moths). These moths have greenish-brown and maroon, or mostly maroon, forewings crossed by two partial, ochre-yellow bands. There is also a prominent yellow band along most of the distal edge of the forewing, hence the common name. There are no named subspecies. The early stages (egg, larvae, and pupae) are undescribed.

Distribution

In Canada, Gold-edged Gems are known from two disjunct populations in the Prairie Ecozone in the southern part of the Prairie Provinces. They occur as a single population at one site in southwestern Manitoba and as a second population at three current and a fourth historical site in southwestern Saskatchewan and adjacent southeastern Alberta. Elsewhere, they are known only from three sites in Colorado.

Habitat

Gold-edged Gems always occur within active sand dunes and blow-outs, in close association with the larval host plant. Suitable habitat appears to consist of colonies of the host plant growing on active dune sands where a suitable adult nectar source is present.

Biology

Adult Gold-edged Gems are active during the day. They can be found resting on, or flying among, the larval host plants or resting on and nectaring at nearby blossoms. They are single-brooded, with adults of Canadian populations present from July 10 to August 20. The only known larval host is the native Prairie Sunflower, and a species of skeletonweed is the primary nectar source used by adult moths.

Population size and trends

The number of sites occupied by the Gold-edged Gem in Canada appears to be stable. There are too few data available on which to base useful population estimates. Based on recent observations at all known occupied Canadian sites, a reasonable estimate is believed to be 700-6,000 adult Gold-edged Gems in Canada in 2004-2005.

Limiting factors and threats

The primary limiting factor is availability of active sand dunes or dunes with “blow-

outs”, supporting colonies of the larval host plant.

The major threat to the long-term survival of the species appears to be the loss of habitat resulting from the stabilization of active sand dunes by both native and introduced vegetation. This natural process has probably accelerated since settlement and the resulting reduction in the number and extent of wildfires. Serious overgrazing of prairie sunflowers could severely impact small, isolated populations of Gold-edged Gems.

Special significance of the species

The Gold-edged Gem is a sand dune specialist, known from only two small populations in Canada and two in the United States (Colorado). 

Existing protection

The Manitoba population is located mostly, or entirely, within Spruce Woods Provincial Park; it may also extend into adjacent CFB Shilo, which is under federal jurisdiction. Two of the four sites where Gold-edged Gems have been found in Alberta (Bindloss) and Saskatchewan (Burstall) are located on private property, and the third (Pakowki Lake) is located on provincially owned leased land; the specific site where the fourth, historic collection was made is unknown.

The Gold-edged Gem is not ranked by the Nature Conservancy (NatureServe), or by the three provinces where it occurs. It is not included on CITES, IUCN or US Fish and Wildlife lists.

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 Secretariat 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^th 2003, the Species at Risk Act (SARA) was proclaimed. SARA establishes COSEWIC Secretariat 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 Secretariat 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 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 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.