BC Conservation Data Centre: Conservation Status Report
Cercyonis pegala incana
Common Wood-nymph, incana subspecies
| Scientific Name: | Cercyonis pegala incana |
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| English Name: | Common Wood-nymph, incana subspecies |
| Provincial Status Summary | |
| Status: | S2? |
| Date Status Assigned: | March 31, 2021 |
| Date Last Reviewed: | March 31, 2021 |
| Reasons: | This species is threatened by ecosystem loss, and fragmentation. There are fewer records and locations. |
| Range | |
| Range Extent: | E = 5,000-20,000 square km |
| Range Extent Comments: | This species is restricted to southern Vancouver Island and the gulf islands, with scattered records in Sunshine Coast and lower mainland areas. |
| Area of Occupancy (km2): | E = 26-125 |
| Area of Occupancy Estimate (km2): | 79 |
| Area of Occupancy Comments: | Updated area of occupancy based on assessment of currently mapped source features (BC CDC 2020). |
| Occurrences & Population | |
| Number of Occurrences: | C = 21 - 80 |
| Comments: | Known from southeast Vancouver Island, Thetis Island, Qualicum Beach, Hornby Island, Wellington, greater Victoria area and other gulf islands. Mainland locations include Powell River and Sechelt. |
| Number of Occurrences with Good Viability / Ecological Integrity: | B = 1 - 3 |
| Comments: | This species has been observed recently, including at least four sites on Hornby Island (Miskelly 2003). One element occurrence is ranked AB (excellent or good estimated viability), while three are ranked BC (good or fair estimated viability), the remaining occurrences are known only as extant (BC CDC 2020). |
| Number of Occurrences Appropriately Protected & Managed: | B = 1 - 3 |
| Comments: | Helliwell Provincial Park; Tribune Bay Provincial Park |
| Population Size: | U = Unknown |
| Threats (to population, occurrences, or area affected) | |
| Degree of Threat: | B = High |
| Comments: | The southern portion of Vancouver Island, the Sunshine Coast, and the lower mainland regions of BC are becoming increasingly fragmented due to habitat conversion. Most, if not all ecosystems within this region are fragmented, and have changed due to invasive species. Much of this area is within private land ownership. Threats to this species include the potential for Btk spray (to control Gypsy Moth infestation (Lymantria dispar)); invasive species encroachment, inadvertent trampling by recreational users; grazing of larval and adult host plants by ungulates. Overall threats include habitat destruction; habitat fragmentation; changes in native vegetation composition from altered fire regimes; recreation; demographic collapse; mowing; changes to hydrology; climate change; maintenance activities; herbivory; pesticides; landscaping with non-native plants; and marine pollution. |
| Trend (in population, range, area occupied, and/or condition of occurrences) | |
| Short-Term Trend: | DE = Decline of 30-70% |
| Long-Term Trend: | D = Decline of 50-70% |
| Comments: | Used habitat loss and change as a proxy for the long-term trends experienced by this subspecies. |
| Other Factors | |
| Intrinsic Vulnerability: | B=Moderately vulnerable |
| Environmental Specificity: | B=Narrow. Specialist or community with key requirements common. |
| Comments: | Butterflies are known to require specific larval and adult food plants for their continued survival in a location. Larvae of C.p.incana are known to use grasses and sedges such as Tridens flavus, Avena fatua, Stipa, Andropoon and Carex (Guppy and Shepard 2001; Layberry et al. 1998). Adults are known to nectar on wildflowers (Layberry et al. 1998). |
| Other Rank Considerations: | The species occurs within the fragmented Garry oak ecosystems, and further decline of this habitat type threatens this subspecies. Invasive plants also threaten its habitat. |
| Information Gaps | |
| Research Needs: | Research to quantify specific habitat requirements (food plant density, size of habitat and foodplant patch), dispersal and recolonization capabilities, reproductive success and population viability; population sizes at each known location. 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 habitats from invasive weeds, adjacent property management and wild fire. Research is also required to assess potential threats from pesticide use and grazing on all life stages. |
| Inventory Needs: | Inventory and long-term monitoring of butterfly populations in the Garry oak ecosystems and lower mainland regions is needed. |
| Stewardship | |
| Protection: | This species and corresponding site specific information should be recorded within protected areas. Monitoring of populations should also occur at known protected areas. |
| Management: | This species is considered a Garry oak ecosystems species. Its food plants and habitat requirements need to be considered in management and planning decisions. Best management practices guidelines for respective land owners need to be developed. |
| Version | |
| Author: | Marks, D. |
| Date: | March 15, 2021 |
| References | |
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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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Layberry, R. A., P. W. Hall, and J. D. LaFontaine. 1998. The butterflies of Canada. University of Toronto Press. 280pp. + color plates.
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Miskelly, J. 2003. Hornby Island: Rare and endangered butterfly inventory 2003. Report prepared for Min. Water, Land and Air Protection, Region 1. 13pp.
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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. 2021. Conservation Status Report: Cercyonis pegala incana. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Sep 23, 2024).