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BC Conservation Data Centre: Conservation Status Report

Camissonia contorta
contorted-pod evening-primrose

Scientific Name: Camissonia contorta
Scientific Name Synonyms: Oenothera cruciata
English Name: contorted-pod evening-primrose
Provincial Status Summary
Status: S1S2
Date Status Assigned: May 06, 2022
Date Last Reviewed: March 31, 2022
Reasons: There are currently 8 known occurrences of Camissonia contorta in British Columbia, all of which are considered extant. The range extent is 2,742 square kilometres and the area of occupancy is 32 square kilometres. The small, fragmented populations may be impacted by habitat loss, recreational use and competition from invasive exotic plants.
Range Extent: D = 1,000-5,000 square km
Range Extent Comments: The range extent for Camissonia contorta, calculated using a convex hull, is 2,742 square kilometres; known from a half dozen locations on southern Vancouver Island and two outlying occurrences on Savary Island.
Area of Occupancy (km2): D = 6-25
Area of Occupancy Comments: The area of occupancy, using a 2km x 2km grid cell for extant occurrences, is 32 square kilometres.
Occurrences & Population
Number of Occurrences: B = 6 - 20
Comments: There are currently 8 known occurrences of Camissonia contorta in British Columbia, all of which are considered extant.
Number of Occurrences with Good Viability / Ecological Integrity: BC = 1 - 12
Number of Occurrences Appropriately Protected & Managed: B = 1 - 3
Population Size: Rank Factor not assessed
Comments: Population size is not considered for plants with an annual life history.
Threats (to population, occurrences, or area affected)
Degree of Threat: AB = Very high - high
Comments: The COSEWIC status report (COSEWIC 2006c) identifies these threats: habitat loss and altered sand dynamics: the introduction of breakwaters, retaining walls, and other shoreline armouring features have eradicated sandy backshore areas; recreational activities (A population in Saanich was extirpated as a direct result of four-wheel-drive activity); and finally, invasive plants known to co-occur with Camissonia with potential to do harm: Cytisus scoparius, Bromus spp., Allium vineale and Ammophila arenaria.
Trend (in population, range, area occupied, and/or condition of occurrences)
Short-Term Trend: Rank Factor not assessed
Long-Term Trend: U = Unknown
Other Factors
Intrinsic Vulnerability: Rank Factor not assessed
Environmental Specificity: Rank Factor not assessed
Other Rank Considerations:
Information Gaps
Research Needs: Subjects that require investigation include dispersal ability and mechanisms (wind, animals, etc.), substrate dynamics (effects of substrate and its movement, etc., on reproductive success), and pollination by insects. Studies are also required to determine by what means and to what degree certain types of disturbance (natural and anthropogenic) affect populations. This could include the effects of invasive plant species. Additionally, population trends need to be investigated, and the sustaining characteristics of these populations need to be identified. This addresses the issue of demographic collapse. At what level (number) are populations considered to be self-sustaining and how do different substrates and conditions affect population viability?
Inventory Needs: Immediate surveys of extant populations are not required, although an inventory monitoring program should be established so that population trends can be determined. The smallest, most vulnerable populations should be monitored diligently to determine status and prevent extirpation. Reports of potential new sites should be documented for future investigation, and surveys of suitable habitat should be completed opportunistically.
Protection: All populations need some level of protection (from gross disturbances) and may require protection from invasive species (especially Cytisus scoparius). Site monitoring will help determine protection needs. Small, concentrated populations are very susceptible to disturbance and eradication and should receive immediate attention. The smallest population of 20 individuals in 1 m2 should be monitored diligently and supported with whatever actions are deemed necessary. These may include exclosures (to humans and small mammals) and the removal of invasives or substrate-binding/covering plants that may impede reproduction, dispersal, and persistence.
Management: Existing populations need to be secured. The immediate need is to prohibit major disturbances that will lead to the probable eradication of the population. This includes major developments (buildings, roads, trails, recreational features). Population monitoring is needed to determine population trends and the levels and types of disturbance that are affecting the populations. This will inform additional management needs.
Author: Henderson, P., Hartwell, S., Donovan, M. and R. Batten
Date: November 23, 2021
COSEWIC. 2006c. COSEWIC assessment and status report on the contorted-pod evening-primrose Camissonia contorta in Canada. Comm. on the Status of Endangered Wildl. in Can. Ottawa. vi + 21 pp.
Fairbarns, M. 2004d. Potential recovery actions for Contorted-pod Evening-primrose in CRD Parks: report prepared for CRD Parks by Aruncus Consulting. 14 pp. + append.

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

Suggested Citation:

B.C. Conservation Data Centre. 2021. Conservation Status Report: Camissonia contorta. B.C. Minist. of Environment. Available: (accessed Nov 29, 2022).