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

Official title: COSEWIC Assessment and Status Report on the Oregon Forestsnail Allogona townsendiana in Canada - 2013

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Endangered
2013

Table of Contents

Document Information

• COSEWIC Assessment Summary
• COSEWIC Executive Summary
• Technical Summary
• Preface
• Wildlife Species Description and Significance
  • Name and Classification
  • Morphological Description
  • Population Spatial Structure and Variability
  • Designatable Units
  • Special Significance
• Distribution
  • Global Range
  • Canadian Range
  • Extent of Occurrence and Index of Area of Occupancy
  • Search Effort
• Habitat
  • Habitat Requirements
  • Habitat Trends
• Biology
  • Life Cycle and Reproduction
  • Physiology and Adaptability
  • Dispersal and Migration
  • Interspecific Interactions
• Population Sizes and Trends
  • Sampling Effort and Methods
  • Abundance
  • Fluctuations and Trends
  • Severe Fragmentation
  • Rescue Effect
• Threats and Limiting Factors
  • Threats to Oregon Forestsnail
  • Number of Locations
  • Limiting Factors for Oregon Forestsnail
• Protection, Status, and Ranks
  • Legal Protection and Status
  • Non-Legal Status and Ranks
  • Habitat Protection and Ownership
• Acknowledgements
  • Authorities Contacted
• Information Sources
• Biographical Summary of Report Writer
• Collections Examined

List of Figures

• Figure 1. Oregon Forestsnail (Allogona townsendiana) adult, June 11, 2010, Colony Farm Metro Vancouver Regional Park. Photograph by Jennifer Heron.
• Figure 2. Oregon Forestsnail (Allogona townsendiana) underside of the shell showing the white apertural lip, June 11, 2010, Colony Farm Regional Park. Photograph by Jennifer Heron.
• Figure 3. Global range of Oregon Forestsnail (Allogona townsendiana), based on Pilsbry (1940, figure 508) and Canadian records (BCConservation Data Centre 2013). Originally published in COSEWIC (2002).
• Figure 4. Canadian distribution of Oregon Forestsnail (Allogona townsendiana) (see Table 1) (BC Conservation Data Centre 2013).
• Figure 5. The Index of Area of Occupancy (IAO) for Oregon Forestsnail.
• Figure 6. Search effort for terrestrial snails within and adjacent to the known range of the Oregon Forestsnail. The current extant sites and historically occupied sites also are shown. Data from the BCConservation Data Centre (2013) up to April 2012 as well as Forsyth (unpubl. data up to 2011) are included (map produced by COSEWIC Secretariat).
• Figure 7. Open and forested habitat at Campbell Valley Regional Park, Langley. Mixed-wood forest with Bigleaf Maple and patches of Stinging Nettle represent potential Oregon Forestsnail habitat, June 1, 2010. Photo Laura Parkinson.
• Figure 8. Oregon Forestsnail (Allogona townsendiana) habitat. Aldergrove Lake Regional Park, Abbotsford. A patch of Stinging Nettle where Oregon Forestsnail were observed, May 19, 2010. Photo Laura Parkinson.
• Figure 9. Oregon Forestsnail (Allogona townsendiana) habitat at Bridal Veil Falls Provincial Park, July 9, 2011. Note dense patch of Stinging Nettle (Urtica dioica) adjacent to a road right-of-way and parking area for recreational vehicles (partially shown). Photo by Jennifer Heron.
• Figure 10. Oregon Forestsnail (Allogona townsendiana) habitat at Colony Farm Regional Park, June 11, 2010. The trail edges and habitat beyond have dense Stinging Nettle (Urtica dioica). Photo by Jennifer Heron.
• Figure 11. Mating individuals of Oregon Forestsnail (Allogona townsendiana) as observed at Trinity Western University Ecological Study area (Figure 2B reproduced with permission from Steensma et al.2009).
• Figure 12. Urban housing projects (red dots on map) in the City of Abbotsford (Greater Vancouver Real Estate 2011). Note the large natural green area to the east is Sumas Mountain.

List of Tables

• Table 1. Sites occupied and Area of Occupancy (AO) for Oregon Forestsnail (Allogona townsendiana) in BC up to April 2012 (BC Conservation Data Centre 2013). While the ASU Chilliwack site is included, no additional data are provided due to the lack of a data-sharing agreement. A "Yes" for "Fragmentation & Isolation" suggests that the site is not viable for Oregon Forestsnail.
• Table 2. Surveys for Oregon Forestsnail (Allogona townsendiana) on Vancouver Island, Gulf Islands and Lower Fraser Valley, BC. Note Search Effort Time (hours) and Search Effort Distance (km) have often not been measured during surveys.
• Table 3. Threat classification table for Oregon Forestsnail. The threat classification below is based on the IUCN-CMP(World Conservation Union–Conservation Measures Partnership) unified threats classification system and is consistent with methods used by COSEWIC, BC Conservation Data Centre and BC Conservation Framework (BC Ministry of Environment 2011a). For a detailed description of the threat classification system, see the Conservation Measures Partnership web site (CMP 2010). For information on how the values are assigned, see Master et al. (2009) and table footnotes for details. Threats for Oregon Forestsnail were assessed across the species geographic range in Canada (Table 1).

List of Appendices

• 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.
• 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.