Spalding's campion (Silene spaldingii) COSEWIC assessment and status report: chapter 2

COSEWIC Executive Summary

Spalding's Campion
Silene spaldingii

Species information

Silene spaldingii is a perennial herb growing from a simple or branched stem base. The erect stems are glandular and hairy, with four to seven pairs of leaves. The inflorescence consists of several to many white flowers in a leafy and usually compact cluster. The fruit consists of an oblong capsule containing light brown seeds.

Distribution

Globally, Silene spaldingiioccurs from southeastern British Columbia to northwestern Montana and from north-central Idaho into eastern Washington and northeastern Oregon. In Canada, S. spaldingii is limited to an area of less than 1 km² on the rolling Tobacco Plains in the vicinity of the town of Roosville.

Habitat

Silene spaldingiioccurs between 580 and 1220 m elevation in the mesic grasslands that make up the Palouse prairie, a division of the Pacific Northwest bunchgrass habitat type. S. spaldingii populations are also known to extend into the edge of Pinus ponderosa woodlands. The species occurs in fragmented patches as a result of large-scale anthropogenic changes to its habitat over the last century, and seems to prefer gently sloping, northerly aspects.

Vegetation associated with Silene spaldingii in Canada includes Festuca species, Lupinus sericeus, Hypericum perforatum, Castilleja tenuis and C. thompsonii. The Silene spaldingii habitat is heavily grazed, with introduced Bromus tectorum occurring throughout.

Biology

Silene spaldingii is a perennial herb arising from a simple or branched stem base formed above a long, slender taproot. Its shoot tips are buried in the ground during the plant’s dormant stage which is typical of plants called “geophytes”.  In the plant’s first year, rosettes are formed, after which vegetative stems are produced. Rhizomes or other means of vegetative propagation are lacking. Flowers are borne in a branched, terminal, inflorescence and bloom in July, setting seed in August. Plants spend nearly 50% of their summers in a dormant condition.

Silene spaldingii is long-lived, usually surviving for at least five years. Recruitment of S. spaldingii is sporadic, and populations are able to persist many years without growth in population numbers. Loss of habitat is the primary factor affecting survival and recruitment in the species. Climatic fluctuations may also be a threat to S. spaldingiipopulations, particularly drought conditions. Non-native plants compete with S. spaldingii for water, nutrients and light, as well as pollinators.

Population sizes and trends

The Canadian Silene spaldingii population consisted of approximately 100 plants in 1995. In 2003 no plants were apparent at the site, probably due to the dormancy characteristics of the species. It is not currently possible to assess the population trend due to lack of information.

Limiting factors and threats

Habitat loss has historically presented the greatest threat to Silene spaldingii. The remaining S. spaldingiihabitat is increasingly affected by invasion of non-native species due to grazing. Fire suppression also threatens S. spaldingii by allowing ingrowth of woody vegetation and accumulation of plant litter. In addition, drought conditions over the past few years are likely increasing stress on S. spaldingii, intensifying anthropogenic pressures.

Special significance of the species

The Canadian population of Silene spaldingii, a total of 100 plants, is at the northern extent of the species’ range and, along with the Montana populations, may represent a genetically distinct element important for the long-term survival and evolution of the species, but this research has yet to be conducted. The species has no commercial value and is not known in cultivation, nor is it known to have cultural, medicinal or spiritual uses.

Existing protection or other status designations

Silene spaldingii is globally ranked as imperiled (G2), and is listed as threatened under the Endangered Species Act (U.S.A.), providing protection for the species on U.S. federal lands. In Canada, the species is ranked N1 but has no federal or provincial protection since the population occurs on private property.

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)*
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 wildlife species for which there is inadequate information to make a direct, or indirect, assessment of its 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.

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

Page details

Date modified: