Scientific Name: Gnaphosa snohomish
Taxonomy Group: Arthropods
Range: British Columbia
Last COSEWIC Assessment: November 2012
Last COSEWIC Designation: Special Concern
SARA Status: No schedule, No Status
Georgia Basin Bog Spider (Gnaphosa snohomish) is a member of the ground spider family (Family Gnaphosidae). Ground spiders are 2-clawed spiders with enlarged, cylindrical, separated anterior lateral spinnerets and modified posterior median eyes. Gnaphosa spiders are characterized by a serrated keel on the posterior margin of the mouthparts. Georgia Basin Bog Spider is similar to other species in the genus and is distinguished by details of the genitalia. The body is 7.5 to 12 mm long. The abdomen is covered with short hairs. The legs are relatively stout with numerous large hairs. The carapace, abdomen, and legs are light brown to dark chestnut brown. The species is endemic to the Puget Sound and Georgia Basin area and about half of the known occurrences are in Canada. (Updated 2017/07/27)
The global distribution of Georgia Basin Bog Spider is restricted to the southern Gulf Islands, Puget Sound and Georgia Basin area of extreme southwestern British Columbia and adjacent Washington. In Canada, it occurs in three bogs and one marsh. Sites on the Gulf Islands (other than Tumbo Island) and adjacent Vancouver Island are believed to be transient and the result of wind dispersal of single individuals. (Updated 2017/07/27)
Georgia Basin Bog Spider is primarily associated with bogs throughout its Canadian and US range. With few exceptions the non-bog occurrences of this spider are of single specimens, likely the result of random ballooning events rather than being an indication of established populations. A cattail marsh on the Gulf Islands is the only known Canadian location for an established population associated with a wetland other than a bog. Five of the six sites in Washington State where this species occurs are bogs. Typical bog habitat is open heath with Sphagnum moss cover and ericaceous shrubs. (Updated 2017/07/27)
Most species in the genus are ground-dwelling nocturnal hunters that actively pursue their prey at night and remain under cover during the day. They are generalist predators on a range of prey including insects and other spiders. Georgia Basin Bog Spider overwinters in the subadult stage and matures in early spring. Life span is probably one year. In addition to simple localized wandering, dispersal of young spiders may occur by ballooning, involving climbing to an elevated perch and extruding a silk thread, which is caught in an updraft and carries the spider away. This method of dispersal is random and success for individual Georgia Basin Bog Spiders depends upon landing in suitable habitat. Ballooning by Georgia Basin Bog Spiders is supported by occurrences of single individuals in non-bog habitat in the Gulf Islands and adjacent Vancouver Island 20 to 30 km from known populations. (Updated 2017/07/27)
Saltwater flooding resulting from rising sea levels (due to climate change), winter storms, and tsunamis could impact all but one site; this is considered to be the most serious threat. Natural system modification, in particular destruction of wetland habitat and succession of native and exotic invasive plant species, currently or potentially impacts all sites of Georgia Basin Bog Spider. Agricultural impacts such as recent and historical peat extraction, cranberry farm development, and related changes to hydrological processes as well as pollution from agriculture, industry, and garbage disposal are important at two sites at least. Overall threat impact is calculated to be “very high” based on NatureServe’s Threat Calculator and seven categories of threat that are relevant. (Updated 2017/07/27)
PLEASE NOTE: Not all COSEWIC reports are currently available on the SARA Public Registry. Most of the reports not yet available are status reports for species assessed by COSEWIC prior to May 2002. Other COSEWIC reports not yet available may include those species assessed as Extinct, Data Deficient or Not at Risk. In the meantime, they are available on request from the COSEWIC Secretariat.
Georgia Basin Bog Spider (Gnaphosa snohomish) is a member of the ground spider family (Family Gnaphosidae). Ground spiders are 2-clawed spiders with enlarged, cylindrical, separated anterior lateral spinnerets and modified posterior median eyes. Gnaphosa spiders are characterized by a serrated keel on the posterior margin of the mouthparts. Georgia Basin Bog Spider is similar to other species in the genus and is distinguished by details of the genitalia. The body is 7.5 to 12 mm long. The abdomen is covered with short hairs. The legs are relatively stout with numerous large hairs. The carapace, abdomen, and legs are light brown to dark chestnut brown. The species is endemic to the Puget Sound and Georgia Basin area and about half of the known occurrences are in Canada.
This small (1 cm) wetland spider has a very limited global distribution, occurring in the Georgia Basin and western Washington State. In Canada, it is known from only 4 sites in southern British Columbia. These populations may become threatened over a very short time period. The greatest threat is inundation by sea water since three of the four known sites are less than 3 m above sea level and are at risk from projected increases in the frequency and severity of storms.
The Multi-species Action Plan for Gulf Islands National Park Reserve of Canada applies to lands and waters occurring within the boundaries of Gulf Islands National Park Reserve (GINPR). The plan meets the requirements for action plans set out in the Species at Risk Act (SARA (s.47)) for species requiring an action plan that regularly occur at this site. Measures described in this plan will also provide benefits to other species of conservation concern that regularly occur at GINPR.
His Excellency the Governor General in Council, on the recommendation of the Minister of the Environment, acknowledges receipt, on the making of this Order, of the assessments done pursuant to subsection 23(1) of the Species at Risk Act by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) with respect to the species set out in the annexed schedule.
Biodiversity is rapidly declining worldwide as species become extinct. Today’s extinction rate is estimated to be between 1 000 and 10 000 times higher than the natural rate. Biodiversity is positively related to ecosystem productivity, health and resiliency (i.e. the ability of an ecosystem to respond to changes or disturbances). Given the interdependency of species, a loss of biodiversity can lead to decreases in ecosystem function and services (e.g. natural processes such as pest control, pollination, coastal wave attenuation, temperature regulation and carbon fixing). These services are important to the health of Canadians, and also have important ties to Canada’s economy. Small changes within an ecosystem resulting in the loss of individuals and species can therefore result in adverse, irreversible and broad-ranging effects.
Under Canada’s Species at Risk Act (SARA), the foremost function of COSEWIC is to “assess the status of each wildlife species considered by COSEWIC to be at risk and, as part of the assessment, identify existing and potential threats to the species”.
COSEWIC held two Wildlife Species Assessment Meetings in this reporting year (October, 2012 to September 2013) from November 25 to November 30, 2012 and from April 28 to May 3, 2013. During the current reporting period, COSEWIC assessed the status or reviewed the classification of 73 wildlife species.
The wildlife species assessment results for the 2012-2013 reporting period include the following:
Special Concern: 19
Data Deficient: 4
Not at Risk: 1
Of the 73 wildlife species examined, COSEWIC reviewed the classification of 50 species that had been previously assessed. The review of classification for 26 of those species resulted in a confirmation of the same status as the previous assessment.
The Government of Canada is committed to preventing the disappearance of wildlife species at risk from our lands. As part of its strategy for realizing that commitment, on June 5, 2003, the Government of Canada proclaimed the Species at Risk Act (SARA). Attached to the Act is Schedule 1, the list of the species provided for under SARA, also called the List of Wildlife Species at Risk. Endangered or Threatened species on Schedule 1 benefit from the protection of prohibitions and recovery planning under SARA. Special Concern species benefit from its management planning. Schedule 1 has grown from the original 233 to 518 wildlife species at risk.
Please submit your comments by
March 23, 2014, for terrestrial species undergoing normal consultations
October 23, 2014, for terrestrial species undergoing extended consultations.