Oregon forestsnail (Allogona townsendiana) COSEWIC assessment and status report 2013: chapter 16

Collections Examined

The following institutional collections were consulted as part of the COSEWIC (2002) status report for Oregon Forestsnail:

Canadian Museum of Nature [CMN], PO Box 3443, Stn. D, Ottawa, ON, Canada K1P 6P4 (museum records).

The Field Museum of Natural History [FMNH], 1400 S. Lake Shore Drive, Chicago, IL, USA 60605-2496

Royal British Columbia Museum [RBCM], 675 Belleville Street, Victoria, BC, Canada V8V 1X4

The following institutions reported that they have no holdings of Oregon Forestsnail (COSEWIC 2002):

Delaware Museum of Natural History [DMNH], 4840 Kennett Pike, PO Box 3937, Wilmington, DE, USA 19807-0937

The Philadelphia Academy of Natural Sciences [ANSP], 1900 Benjamin Franklin Parkway, Philadelphia, PA, USA 19103

Royal Ontario Museum [ROM], 100 Queen’s Park, Toronto, Ottawa, ON, Canada M5S 2G6

Smithsonian Institution [USNM], Washington, DC, USA 20560-0163

Appendix 1. List of Oregon Forestsnail Museum and Collection Records up to 2001. CMH: Canadian Museum of Nature, Ottawa; RBCM: Royal British Columbia Museum, Victoria; FMNH: Field Museum of Natural History, Chicago.
Museum No./ Published record Site Geoposition Year Date Number Individuals /specimens
CMN 002988; Whiteaves 1906 Chilliwack River   1901 1901-VI-20 1
CMN 002995 E&N railroad ¼ mi. NW of Westholme Station, Vancouver I.   1903   2
CMN 008003 SW of Abbotsford 49°02´N, 122°18´W 1954 1954-VI-27 10
CMN 007182 E side of Abbotsford 49°02´N, 122°18´W 1954 1954-VI-27 4
CMN 008164 South shore of Fraser River, Chilliwack 49°06´N, 121°56´W 1959 1959-05-24 5
CMN 008234 Vedder Crossing   1959 1959-07-17 6
CMN 008134 S shore of Fraser River, Chilliwack 49°06´N, 121°56´W 1959 1959-V-15 3
CMN 008125 Vedder Crossing   1959 1959-V-21 2
CMN 008145 Vedder Crossing   1959 1959-V-21 2
CMN 008038 Vedder Crossing   1959 1959-V-25 1
CMN 008147 Prairie Central & Patterson Rd., Chilliwack   1959 1959-V-26 1
CMN 008045 S shore of Fraser River, Chilliwack 49°06´N, 121°56´W 1959 1959-V-29 1
CMN 008596 South shore of Fraser River, Chilliwack 49°06´N, 121°56´W 1959 1959-V-29 1
CMN 008948 South shore of Fraser River, Chilliwack 49°06´N, 121°56´W 1959 1959-V-29 20
CMN 008944 South shore of Fraser River, Chilliwack 49°06´N, 121°56´W 1959 1959-VI-15 15
CMN 008152 Elk Creek Power House   1959 1959-VII-07 1
CMN 008945 Elk Creek Power House   1959 1959-VII-07 1
CMN 008042 Silver Creek, 7 mi. S of Hope 49°20´N, 121°28´W 1959 1959-VII-09 2
Cameron 1986 Locality 7; =Cheam Lake Regional Park 49°11.9´N, 121°45.0´W 1984   2
Cameron 1986 Locality 8; =Bridal Veil Falls Prov. Park 49°11.1´N, 121°44.5´W 1984   2
Ovaska et al. 2001; RBCM 000-099-001 Bridal Veil Falls Provincial Park 49°11.1´N, 121°44.5´W 2000 22-IV-2000 5
Ovaska et al. 2001 Near Yarrow, Chilliwack 49°04.7´N, 122°02.5´W 2000 22-IV-2000 3
Ovaska et al. 2001; RBCM 000-104-001 Near Cheam Lake 49°11.9´N, 121°45.0´W 2000 22-IV-2000 1
Ovaska et al. 2001 Herrling Island Road 49°14.8´N, 121°45.0´W 2000 22-IV-2000 1
Ovaska et al. 2001; RBCM 000-103-001 Hopyard Hill, Agassiz 49°13.99´N, 121°46.98´W 2000 23-IV-2000 2
Ovaska et al. 2001 Cemetary Hill, Agassiz 49°14.21´N, 121°48.11´W 2000 23-IV-2000 9
Ovaska et al. 2001; RBCM 000-102-001 Nicomen Slough, Hodgekins Rd. 49°12.51´N, 122°00.44´W 2000 23-IV-2000 1
Ovaska et al. 2001; RBCM 000-101-001 Warton Creek, Neilson Regional Park, Mission 49°09.5´N, 122°14.9´W 2000 23-IV-2000 3
Ovaska et al. 2001 Nicomen Island, 900 m SW of Deroche 49°10.74´N, 122°04.50´W 2000 23-IV-2000 1
Ovaska et al. 2001; RBCM Tamihi Creek, Chilliwack Valley 49°04.25´N, 121°50.46´W 2000 30-IV-2000 6
Ovaska et al. 2001 Trinity Western University, Langley 49°08.3´N, 122°35.7´W 2001 08-IX-2001 5
Ovaska et al. 2001 Warton Creek, Neilson Regional Park, Mission 49°09.5´N, 122°14.9´W 2001 09-VI-2001  
Ovaska et al. 2001 St. Mary’s Park, W side of D’Herbomez Creek, Mission 49°08.5´N, 122°16.9´W 2001 09-VI-2001 2
Field Museum of Natural History 146670 Agassiz     ? 1
Dall 1905; repeated by La Rocque 1953 Chilliwack Lake     ? ?
Dall 1905; repeated by La Rocque 1953 Sumas Prairie     ? ?
Whiteaves 1906 as Polygyra ptychophora; USNM? Mission Junction     ? ?

Appendix 2. Geographic Information System (GIS) mapping exercise overlaying known Oregon Forestsnail occurrence records with projected urban growth boundary layers in the Fraser Valley Regional District.

The core areas of natural habitat remaining within the geographic range of Oregon Forestsnail in Canada are within the municipalities of Abbotsford, Chilliwack, Harrison Hot Springs, Hope, Kent, District of Langley and Mission. Together, these municipalities, in part, form the Fraser Valley Regional District (FVRD).

The FVRD, including all municipal governments within the boundaries, began their urban growth strategy in 1996 and finalized their Regional Growth Strategy in 2004. Within the FVRD Regional Growth Strategy there are urban growth boundaries (Table 2.1) which aim to contain urban growth. It is expected that within a 20 - 30 year time frame (2004-2034) these areas will be highly developed as urban centres within the FVRD. At present, the amount of urban growth (non-natural habitat) within these areas is not mapped, but it can be assumed only habitat not within the Agricultural Land Reserve or within protected areas, is targeted for urban growth.

Table 2.1. Amount of area contained within urban growth boundaries of the Fraser Valley Regional District (FVRD).
FVRD Municipalities Area within urban growth boundaries (ha)
Abbotsford 7587
Chilliwack 4405
Harrison Hot Springs 343
Hope 713
Kent 718
Langley (District of) 2
Mission 3370
Total 17,138

For this exercise, known Oregon Forestsnail occurrence records from the BC Conservation Data Centre were overlaid with urban growth boundary layers. In the Lower Mainland and Lower Fraser Valley, Oregon Forestsnail is recorded from Burnaby to Hope, with the majority of records being from the FVRD (Figure 2.1). Each municipality within the FVRD has a defined "urban growth boundary" – a geographic area where the municipality will focus approvals for increased development and urban growth densification (e.g., housing, commercial, industrial, etc.) (Figure 2.2). These become human population centres.

Each municipality has separate bylaws that require development proposals to consider environmental values such as species at risk. Abbotsford has some of the most stringent environmental bylaws in the province, and requires proponents to collect data on species at risk under specific Wildlife Assessment Report Guidelines (City of Abbotsford 2010). Therefore the best data on Oregon Forestsnail distribution as well as GIS habitat overlays is available for the Abbotsford region, which is south of the Fraser River across from Mission (Figure 2.3). The Fraser Valley Regional Growth Strategy (2004) projected development from 2004 - 2034 defines the urban growth boundary for the City of Abbotsford at 7587 ha; the urban growth boundary for Mission is 3370 ha (FVRD 2004). Some of the urban growth boundary is currently developed (e.g., housing and infrastructure) and some is currently natural land (private). Data are collected on Oregon Forestsnail distribution during development proposal planning processes in the City of Abbotsford and were used for the construction of habitat suitability maps on Sumas Mountain.

Sumas Mountain is 6600 ha and one of the last relatively intact forested areas in the Lower Fraser Valley. A total of 4570 ha (70%) of the mountain is within the Abbotsford urban growth boundary (City of Abbotsford 2010), which is 60% of the total urban growth boundary for Abbotsford (Table 2.1). The suitability of habitat for Oregon Forestsnail was mapped for 3900 ha (59%) of Sumas Mountain (City of Abbotsford 2010; Bettles pers. comm. 2013; Durand pers. comm. 2013) (Figure 2.4). Within the mapped study area of Sumas Mountain there are 624 known occurrences of the Oregon Forestsnail (City of Abbotsford 2010). Habitat suitability for the snail is based on sensitive ecosystem mapping information (Durand pers. comm. 2013) and was divided into four categories:

high = snail presence, older > 50 years, broadleaf forest;

moderate = some polygons have snails, younger disturbed broadleaf forest but with natural forest attributes;

low = very few to no snail presence, natural but disturbed areas;

nil = urban development and no possibility of snail habitat

GIS was used to overlay the Abbotsford urban growth boundary onto the mapped mollusc suitability on Sumas Mountain (City of Abbotsford 2010). A total of 465 ha of the mapped area within the urban growth boundary of Abbotsford is considered to have high suitability for the snail (Figure 2.4). Similarly, 41 ha has moderate, 82 ha has low, and 499 ha has no suitability, likely because this land is already developed. This means that 47% of the 1087 ha of mapped habitat on Sumas Mountain within the urban growth boundary of Abbotsford has high or moderate suitability for Oregon Forestsnail and can be expected to be lost when urban development occurs from 2004-2034. However, only 14% (or 1087 ha) of the total 7587 ha within the urban growth boundary of Abbotsford has been mapped for suitability for Oregon Forestsnail.

The District of Mission also requires development to consider Oregon Forestsnail. The most recent example of a large urban development project was the "Wren Creek Development" (see Figures 13 and 14 in the main report), which through the development process was deemed to have high environmental values. Concern over the impacts to Oregon Forestsnail was expressed by both the Canadian Wildlife Service and BC Ministry of Forests, Lands and Resource Operations (see Scott Resource Services Inc. 2011). Wren Creek development received final approval on 16 April 2012 (MacNair 2012) despite the presence of Oregon Forestsnail.

Urban growth boundaries for the areas around Chilliwack also contain polygons mapping known Oregon Forestsnail sites (Figure 2.5). While the polygon showing the known Oregon Forestsnail site around Hope are outside the urban growth boundary (Figure 2.6), there are known Oregon Forestsnail sites within the urban growth boundary near Kent (Figure 2.7). Similar to Abbotsford (Figure 2.3), point records for Oregon Forestsnail within the urban growth boundaries of these cities also are not available.

While the overall amount of habitat loss that has occurred in the past and is projected to occur into the future over the entire range of Oregon Forestsnail is untallied, it can be concluded that all areas within the urban growth boundary are slated for future land conversion and development. This development will eliminate most large contiguous Oregon Forestsnail habitats, and the small pieces of habitat that remain as part of municipal set-aside requirements, riparian corridors, or compensation are likely to be sinks with snail populations declining to or nearly to zero in the short term (< 10 years).

If development occurs within the entire urban growth boundaries (Table 2.1) of the FVRD, a 171.38 km2 reduction in natural habitat can be expected within the next 30 years. It is currently not possible, given the available data, to quantify the effects of this urban development on reductions in EO, IAO, number of populations, and number of mature individual Oregon Forestsnail; however, the outlook is not good.

References (in addition to those in main body of report):

Bettles, T., pers. comm. 2013. Personal communication to Jennifer Heron (phone and email). February 21, 2013. Environmental Coordinator, City of Abbotsford, British Columbia.

City of Abbotsford. 2010. Sensitive Ecosystem Inventory Mapping project. Completed by R. Durand for the City of Abbotsford, BC. Summary report available at City of Abbotsford [accessed 22 February 2013].

City of Abbotsford Wildlife Assessment Report Guidelines. 2010. Available at City of Abbotsford [accessed February 19, 2013].

Durand, R., pers. comm. 2013. Personal communication to Jennifer Heron (phone and email). February 19, 2013. Biologist, Taara Environmental, Crescent Valley, British Columbia.

Fraser Valley Regional District (FVRD). 2004. Fraser Valley Regional District Growth Strategy. Available at Fraser Valley Regional District [accessed February 15, 2013]

MacNair, A. 2012. Wren Creek development receives approval despite opposition. Newspaper article in the Mission City Record available at Mission City Record [accessed February 19, 2013].

Scott Resources Services Inc. 2011. Letter to Mayor and Council, District of Mission. Adoption of agenda item to Regular Council Meeting, 17 October 2011. Web site: District of Mission [accessed 19 February 2013].


Figure 2.1. Municipalities in the Lower Mainland and Lower Fraser Valley, with Oregon Forestsnail records (habitat polygon data, BC Conservation Data Centre 2013.

Map giving an overview of Oregon Forestsnail occurrence (see long description below).

Note: large circular polygons represent occurrences with low representational accuracy). Oregon Forestsnail occurs within two regional government districts: Metro Vancouver (Burnaby, Delta, Surrey, White Rock, Coquitlam, Maple Ridge) and Fraser Valley Regional District (Langley, Abbotsford, Mission, Chilliwack, Kent, Harrison Hot Springs and Hope).

Description of Figure 2.1

Map giving an overview of Oregon Forestsnail occurrence in the Lower Mainland and Lower Fraser Valley. Occurrences of Oregon Forestsnail are indicated in areas. Municipal boundaries are outlined. The Fraser Valley Regional District urban growth boundaries are indicated. Parks, Indian reserves, and private land are also indicated.

 


Figure 2.2. Overview range map of Oregon Forestsnail in the Fraser Valley Regional District (FVRD)

Map giving overview of Oregon Forestsnail range in the Fraser Valley Regional District (see long description below).

FVRD is made up of numerous municipalities including Abbotsford, Langley (District), Mission, Chilliwack, Hope, Kent, Harrison Hot Springs (and others) with Oregon Forestsnail records (BC Conservation Data Centre 2013).

Description of Figure 2.2

Map giving overview of Oregon Forestsnail range in the Fraser Valley Regional District. Occurrences of Oregon Forestsnail are indicated. Municipal boundaries are outlined. The Fraser Valley Regional District urban growth boundaries are indicated. Parks, Indian reserves, and private land are also indicated.

 


Figure 2.3. Urban growth boundaries of Abbotsford and Mission, showing Oregon Forestsnail occurrences (BC Conservation Data Centre 2013).

Map showing the urban growth boundaries of Abbotsford and Mission (see long description below).

Abbotsford urban growth boundary is 7587 ha and Mission 3370 ha, projected for development from 2004 - 2034 (FVRD 2004). The green patch extending northwest of the urban growth boundary for Abbotsford includes Sumas Mountain.

Description of Figure 2.3

Map showing the urban growth boundaries of Abbotsford and Mission and Oregon Forestsnail occurrence. Municipal boundaries are indicated. Parks, Indian reserves, and private land are also indicated. Also shown are agricultural, forest, limited use, and rural/rural resource areas.

 


Figure 2.4. Suitability of habitat for Oregon Forestsnail within the urban growth boundary of Abbotsford on Sumas Mountain

Map showing suitability of habitat for Oregon Forestsnail (see long description below).

City of Abbotsford 2010; Bettles pers. comm. 2013; Durand pers. comm. 2013.

Description of Figure 2.4

Map showing suitability of habitat for Oregon Forestsnail within the urban growth boundary of Abbotsford on Sumas Mountain and Oregon Forestsnail occurrence. The degree of habitat suitability is shown. Details of high suitability, moderate suitability; low suitability and unsuitable are indicated in detail.

 


Figure 2.5. Urban growth boundaries of Chilliwack and surrounding areas, showing Oregon Forestsnail occurrences.

Map showing urban growth boundaries for Chilliwack and surrounding areas (see long description below).

BC Conservation Data Centre 2013. Chilliwack urban growth boundary is 4405 hectares, projected for development from 2004 - 2034 (FVRD 2004).

Description of Figure 2.5

Map showing urban growth boundaries for Chilliwack and surrounding areas and Oregon Forestsnail occurrences. Municipality boundaries are indicated. Parks, Indian reserves, and private land are indicated. Also shown are agricultural, commercial outdoor recreation; residential; limited use, and natural resource / outdoor resource areas.

 


Figure 2.6. Urban growth boundaries of Hope and surrounding areas, showing Oregon Forestsnail occurrences.

Map showing urban growth boundaries for Hope and surrounding areas (see long description below).

BC Conservation Data Centre 2013. Hope urban growth boundary is 713 hectares, projected for development from 2004 - 2034 (FVRD 2004).

Description of Figure 2.6

Map showing urban growth boundaries for Hope and surrounding areas and Oregon Forestsnail occurrences . Municipality boundaries are indicated. Parks, Indian reserves, and private land are indicated. Also shown are agricultural and limited use areas.

 


Figure 2.7. Urban growth boundaries of Kent and surrounding areas, showing Oregon Forestsnail occurrences.

Map showing urban growth boundaries of Kent and surrounding areas (see long description below).

BC Conservation Data Centre 2013. Kent urban growth boundary is 718 hectares, projected for development from 2004 - 2034 (FVRD 2004).

Description of Figure 2.7

Map showing urban growth boundaries of Kent and surrounding areas and Oregon Forestsnail occurrences. Municipality boundaries are indicated. Parks, Indian reserves, and private land are indicated. Also shown are limited use ; natural resource / outdoor resource; rural / rural resource; commercial recreation; agriculture; industrial; commercial/industrial; park / recreation and open space; and resource management areas.

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