BC Conservation Data Centre: Conservation Status Report
Euphyes vestris
Dun Skipper
| Scientific Name: | Euphyes vestris |
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| English Name: | Dun Skipper |
| Provincial Status Summary | |
| Status: | S2S3 |
| Date Status Assigned: | February 01, 2020 |
| Date Last Reviewed: | February 01, 2020 |
| Reasons: | Low number of occurrences; hight threats to habitat within the species' range. |
| Range | |
| Range Extent: | F = 20,000-200,000 square km |
| Range Extent Comments: |
Based on known records, the historic and present (combined) range extent of occurrence is 32,597 sq. km (25,924 sq. km for the mainland and 6673 sq. km for Vancouver Island and Gulf Islands) (Heron 2011). Recently (2018) there has been a range extension to the Pend-d'Oreille Valley, along the Salmo River (INaturalist ND; accessed Feb. 2020; confirmed by C.Guppy in 2018). On Vancouver Island, Dun Skipper ranges from the Greater Victoria area north to Courtney/Comox. Known Gulf Island localities include Salt Spring Island, Denman Island and Hornby Island. Within the lower Fraser Valley the species northernmost location is Lillooet ranging south through Boston Bar, Yale and Hope and into the lower mainland area at Burns Bog. West, the species has records in Pemberton and Powell River (Heron 2011). |
| Area of Occupancy (km2): | E = 26-125 |
| Area of Occupancy Comments: | The Index of Area Occupancy using a 2 km x 2 km grid is 188 sq. km; 26-125 4-km2 grid cells (Heron 2011). |
| Occurrences & Population | |
| Number of Occurrences: | C = 21 - 80 |
| Comments: | There are 23 element occurences in B.C. (BC Conservation Data Centre accessed 2012) within the coastal lowlands of the lower Fraser Valley, the southern Gulf Islands and southeastern Vancouver Island. (29 as of 2020-Jan) + |
| Number of Occurrences with Good Viability / Ecological Integrity: | U = Unknown |
| Comments: | The species is difficult to assess for viability due to the rarity in a documented location. There are likely 10 element occurrences with good viability, including Burns Bog, various locations on Vancouver Island, Saltspring Island, Helliwell Provincial Park |
| Number of Occurrences Appropriately Protected & Managed: | C = 4 - 12 |
| Comments: | Protected locations include Burns Bog (GVRD) in 2004; Thetis Lake Regional Park; Goldstream Provincial Park; Francis King Regional Park; Spectacle Lake Provincial Park; Helliwell Provincial Park on Hornby Island. There is no species specific management in these protected areas. |
| Population Size: | U = Unknown |
| Comments: |
Population sizes and trends are not available for Dun Skipper in B.C. (Heron 2011). The species is difficult to assess due to the rarity in a documented location - usually only seen as one or two specimens at any one time. |
| Threats (to population, occurrences, or area affected) | |
| Degree of Threat: | AB = Very high - high |
| Comments: |
The following threats are taken from the 2011 draft COSEWIC report: Loss of habitat from urban and rural land conversion is a threat to the Dun Skipper as the lower Fraser Valley and southeastern Vancouver Island are developing areas. Through land conversion, fragmentation of the necessary open, wet habitat and plant communities may occur. Natural forest succession is a threat to the Dun Skipper which require open habitat with abundant light and moisture. Fire suppression, within Garry oak and associated habitat, has led to further natural forest succession within open habitat thus causing a decline in potential Dun Skipper habitat. Invasive species are a threat to the Dun Skipper as habitat may become degraded or dominated by species such as Scotch Broom (Cytisus scoparius L.). As well the Dun Skipper is within the range for potential introduction of European Gypsy Moth (Lymantria dispar L.). Should significant numbers of Gypsy moths be found the pesticide Btk (Bacillus thuringiensis kurstak) could possibly be sprayed within the range of the Dun Skipper. Btk for gypsy moth is typically applied in early April to early May, which coincides with the Dun Skipper larval activity. Climate change is a potential threat to the Dun Skipper; primarily due to the impacts such change brings to the wetland ecosystem and plant communities within which the species lives. Climate change may increase summer drought on southeastern Vancouver Island and the lower Fraser Valley, potentially resulting in premature senescence of larval and nectar host plants. Overall, there is significant urban/agricultural development within the species BC range. The habitat is known to be open, grassy, moist to wet meadows with significant sedge components. The species is typically found at roadsides where ditches/wet areas occur and sedges are growing. Wetlands, old moist fields and ditches are being filled (lower mainland region and greater Victoria region). Species specific threats may be the hostplant specificity at a given site (although numerous sedges may be available for consumption, the species is hostplant specific to one or two species of sedges). Additional threats include the possibility of Btk spray for gypsy moth (Lymantria dispar) and invasive species. |
| Trend (in population, range, area occupied, and/or condition of occurrences) | |
| Short-Term Trend: | F = Decline of 10-30% |
| Comments: | The species may be impacted at select locations by road maintenance, ditch digging or wetland filling/development. Invasive species, filling in of ditches and roadside wetlands, fragmentation of the landscape and overall changes to habitat all threaten the species and declining trend. |
| Long-Term Trend: | E = Decline of 30-50% |
| Comments: | Overall, there is significant urban/agricultural development within the species BC range. Wetlands, old moist fields and ditches are being filled. |
| Other Factors | |
| Intrinsic Vulnerability: | C=Not intrinsically vulnerable |
| Environmental Specificity: | B=Narrow. Specialist or community with key requirements common. |
| Comments: | Like all butterflies, this species relies on a given foodplant(s) for its existence and without these food sources the butterfly will not persist in a given area. The specific foodplants for this species are unknown, but the butterfly likely relies on sedges. The species is thought to exhibit hostplant specificity in a given location, but over its entire range may have numerous hostplants. |
| Other Rank Considerations: | |
| Information Gaps | |
| Research Needs: | Specific habitat requirements (food plant density, size and habitat requirements), dispersal capabilities, reproductive success and population viability. Additional research to assess the potential impacts of predation, parasitism, climatic variation, small population size, and population isolation is also needed. Research is required to assess the potential threats to habitat from invasive weeds. |
| Inventory Needs: |
Inventory and monitoring of all butterflies throughout British Columbia, specifically the lower mainland as this area is under extreme development pressures from both the agricultural and housing sectors. Monitoring of known populations within protected areas is needed. Further surveys in the Lillooet and Pemberton regions are required, focusing on IDFww, CWHds1/dm2 and PPxh2 biogeoclimatic zones. Future range extension activity should focus on adjacent valleys in the IDFww and CWHds1 biogeoclimatic zones, in addition to PPxh2. Habitat appears to be limited in the CWHdm subzones, but appropriate sites should be investigated (Knopp et al. 2008). |
| Stewardship | |
| Protection: | Species specific management within protected areas is needed. |
| Management: | This species needs to be incorporated into parks and protected areas planning documents. Best management practises guidelines for private landowners such as urban/agricultural developers, municipalities and highways maintenance workers and forest companies. This species is a likely candidate for the Identified Wildlife Management Strategy under the BC Forest and Range Practises Act. |
| Version | |
| Author: | Heron, J., Wilson, K. |
| Date: | July 12, 2012 |
| References | |
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BC Conservation Data Centre: Conservation Data Centre Mapping Service [web application]. 2006. Victoria, British Columbia, Canada. Available: http://maps.gov.bc.ca/imf50/imf.jsp?site=cdc.
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Guppy, C.S., and J.H. Shepard. 2001. Butterflies of British Columbia. UBC Press in collaboration with Royal B.C. Mus. 414pp.
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iNaturalist. Website. Available: http://www.inaturalist.org/
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Knopp, D., L. Larkin and J. Heron. 2008. Survey for Dun Skipper in the Lower Fraser Valley, B.C. B.C. Ministry of Environment, UBC Campus, 315-2202 Main Mall, Vancouver B.C. 53 pp.
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Please visit the website Conservation Status Ranks for information on how the CDC determines conservation status ranks. For global conservation status reports and ranks, please visit the NatureServe website http://www.natureserve.org/.
Suggested Citation:
B.C. Conservation Data Centre. 2012. Conservation Status Report: Euphyes vestris. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Jun 13, 2026).