BC Conservation Data Centre: Conservation Status Report
Viola biflora var. carlottae
Haida Gwaii twinflower violet
| Scientific Name: | Viola biflora var. carlottae |
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| English Name: | Haida Gwaii twinflower violet |
| Provincial Status Summary | |
| Status: | S3S4 |
| Date Status Assigned: | April 30, 2019 |
| Date Last Reviewed: | April 30, 2019 |
| Reasons: | Viola biflora ssp. carlottae is known from at least 31 occurrences on the Queen Charlotte islands, and northern Vancouver Island (few locations) within a range of about 14000 square km. It is likely that V. biflora will be found in many more locations due to the availability of suitable habitat within its range. The liklihood, timeframe and severity of potential development threats (hydroelectric power, windfarms, and telecommunication installations) are not known, but it appears that it is only slightly threatened by any of these. |
| Range | |
| Range Extent: | E = 5,000-20,000 square km |
| Range Extent Comments: | Viola biflora ssp. carlottae is locally frequent on the Queen Charlotte Islands and northwest Vancouver Island; endemic to BC and southeast Alaska. It occurs over about 14000 square km in BC. |
| Area of Occupancy (km2): | AD = 1-25 |
| Area of Occupancy Comments: | Viola biflora ssp. carlottae in BC occupies about 4850 to 4980 square meters (a tally from occurrences where population data was available, in less than 31 sites). This likely represents an underestimated value, due to the fact that there are likely many more occurrences. |
| Occurrences & Population | |
| Number of Occurrences: | C = 21 - 80 |
| Comments: | There are 31 documented occurrences for this species. Given that there is ample suitable habitat within its range, there are likely upwards of 100 or more sites for this species. |
| Number of Occurrences with Good Viability / Ecological Integrity: | Rank Factor not assessed |
| Number of Occurrences Appropriately Protected & Managed: | D = 13 - 40 |
| Comments: | Fifteen populations are known to be protected in Gwaii Haanas National Park. |
| Population Size: | E = 2,500 - 10,000 individuals |
| Comments: | There are about 8100 to 9700 individuals in the 37 documented occurrences, though this likely represents an underestimation as there are likley many more sites and plants in BC. |
| Threats (to population, occurrences, or area affected) | |
| Degree of Threat: | Slightly threatened |
| Comments: |
Potential threats include development of wind farms, telecommunications installations, and hydroelectric dams. Deer browsing, especially in the long term, has been proposed as general imminent threat for native vegetation on the Queen Charlotte Islands, but has not been observed as a threat to this species in its mountain habitats. |
| Trend (in population, range, area occupied, and/or condition of occurrences) | |
| Short-Term Trend: | U = Unknown |
| Long-Term Trend: | U = Unknown |
| Other Factors | |
| Intrinsic Vulnerability: | U=Unknown |
| Environmental Specificity: | D=Broad. Generalist or community with all key requirements common. |
| Comments: | Viola biflora in BC occurs in blanket bogs, moist shaded clefts in rocks, on wind eroded cobble & rock blocks, on ledges, in crevices, in limestone sink holes, on alpine scree slopes and on rock cliffs. |
| Other Rank Considerations: | |
| Information Gaps | |
| Research Needs: | |
| Inventory Needs: | |
| Stewardship | |
| Protection: | |
| Management: | |
| Version | |
| Author: | J.L. Penny |
| Date: | February 16, 2004 |
| References | |
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Douglas, G.W., D. Meidinger, and J. Penny. 2002. Rare Native Vascular Plants of British Columbia, 2nd ed. B.C. Conserv. Data Centre, Terrestrial Inf. Branch, Victoria. 358pp.
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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. 2004. Conservation Status Report: Viola biflora var. carlottae. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Jun 4, 2026).