Oregon forestsnail (Allogona townsendiana) COSEWIC assessment and status report 2013: chapter 5
Oregon Forestsnail (Allogona townsendiana) was assessed by COSEWIC in 2002 as Endangered. Since the first status report was prepared, new information on the distribution and habitat, habitat trends, threats and limiting factors has been gathered through inventory and research. Studies on life history, including clutch size and egg-laying sites, overwintering and aestivation sites, home range, food preferences, and association with Stinging Nettle (Urtica dioica), also have been completed.
From 2000 – 2011 substantial search effort for Oregon Forestsnail has resulted in additional sites within the species’ range in British Columbia (BC). Search effort has focused on the edges of the range yet the range has not been substantially expanded. The historical record on Vancouver Island at Westholme (1903) near Crofton was confirmed in 2003 and again in 2009.
Since 2000, over 1080 sites have been surveyed for gastropods within the range of Oregon Forestsnail. In 2002 there were 37 known sites for Oregon Forestsnail, and as of 2011 there are 66 known occupied sites. Site abundance ranges from one individual (at least 17 sites) to counts greater than 20 snails (9 sites). The largest number of observations at one time is 670 individuals at Colony Farm Regional Park.
While more sites have been found to be occupied by the snail, due to increased search effort as a consequence of listing as Endangered under the Species at Risk Act, 52 of the 66 known sites (78.8%) and 50 of the 75 occupied 2 km x 2 km grid cells (66.7%) were assessed as fragmented and isolated. At least 50 sites are less than 5 ha in size and/or are subject to urban development within the next 10 years (see Threats and Limiting Factors). These sites are isolated by distances of more than 1 km of unsuitable habitat as a result of past land development (since 2002) and most likely will not be able to maintain a viable snail population in the future.
The most serious and plausible threat identified in the original status report – urban development – continues to further fragment and eliminate Oregon Forestsnail habitat in the densely populated Lower Fraser Valley region of BC.
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 (2013)
- 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.
The Canadian Wildlife Service, Environment Canada, provides full administrative and financial support to the COSEWIC Secretariat.