BC Conservation Data Centre: Conservation Status Report
Plagiobothrys figuratus var. figuratus
fragrant popcornflower
| Scientific Name: | Plagiobothrys figuratus var. figuratus |
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| Scientific Name Synonyms: |
Plagiobothrys figuratus
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| English Name: | fragrant popcornflower |
| Provincial Status Summary | |
| Status: | S1 |
| Date Status Assigned: | April 30, 1996 |
| Date Last Reviewed: | April 30, 2019 |
| Reasons: | A total of 12 occurrences have been documented historically in British Columbia, only one of which may still be extant. No plants have been observed in BC since 2005 or possibly 2011, despite ongoing monitoring of the last extant site. The one recently observed location occurs on private land beside a road in a residential area and is highly vulnerable to both human and stochastic disturbances, competition from invasive species, and impacts of climate change. The scope and severity of threats are high. Total population size for P. figuratus in BC is zero, with the possible exception of a persistent seed bank. Short-term (10-yr) trends are unknown, but there is strong evidence of historical declines in BC. |
| Range | |
| Range Extent: | A = <100 square km |
| Range Extent Comments: | The Range Extent is presently equal to the Area of Occupancy. |
| Area of Occupancy (km2): | AC = 1-5 |
| Area of Occupancy Comments: | As of 2005 (when plants were last observed), the occupied habitat was less than 1 m-sq. Using a 2 km x 2 km grid analysis, this species occupies 1 grid (4 sq km). The habitat patch where Plagiobothrys figuratus was last observed has an overall area of approx. 300-sq m (M. Fairbarns and M. Miller, pers. comm. 2009). |
| Occurrences & Population | |
| Number of Occurrences: | A = 1 - 5 |
| Comments: | The last reported Canadian occurrence of Plagiobothrys figuratus is from Hornby Island (COSEWIC 2008). No individuals have been documented at this site since 2005 (M. Fairbarns and M. Miller, pers. comm. 2009) but there is an unconfirmed report of plants from 2011. Historically, Fragrant Popcornflower was found along the southeastern coast of Vancouver Island from Comox to Victoria. Between 1885 and 1986, the species was recorded a total of 12 times from a minimum of seven independent locations: Comox, Nanaimo, Wellington, Hornby Island (two sites), Victoria, and Cedar Hill. However, the precise historical range cannot be determined from the limited information available from collection notes. Most historical localities have presumably been lost to urban development (COSEWIC 2008). |
| Number of Occurrences with Good Viability / Ecological Integrity: | A = None (zero) |
| Comments: | The last remaining extant occurrence (on Hornby Island) is thus thought to have very low viability since no plants have been observed there since 2005 (COSEWIC 2008). |
| Number of Occurrences Appropriately Protected & Managed: | A = None |
| Comments: | There are no protected occurrences of Plagiobothrys figuratus in Canada. The last documented extant occurrence is located on private land. |
| Population Size: | A = 1 - 50 individuals |
| Comments: | The last documented extant occurrence, located on Hornby Island, has not produced any flowering plants since 2005 when a single flowering individual was observed. Prior to 2005, the last known observation of Plagiobothrys figuratus in Canada was at this same site in 1986. It is possible that the population still persists in the form of a dormant seed bank, but this has not been confirmed (COSEWIC 2008). |
| Threats (to population, occurrences, or area affected) | |
| Degree of Threat: | Substantial, imminent threat |
| Comments: | The last documented locality for Plagiobothrys figuratus is a semi-overgrown vernal pool depression in a remnant patch of coastal meadow situated adjacent to a paved road. Potential threats to Plagiobothrys figuratus include invasive alien plant encroachment, residential development, road maintenance, and climate change (COSEWIC 2008, M. Fairbarns and M. Miller, pers. comm 2009). Of these, only invasive species are known to pose a continuing and imminent threat (M. Fairbarns and M. Miller, pers. comm. 2009). The site suffers from significant thatch accumulation from introduced grasses such as Sweet Vernal Grass and Soft Brome, while invasive herbs such Ribwort Plantain and Hairy Cat's-ear may be competing with P. figuratus for resources and space (M. Fairbarns and M. Miller, pers. comm. 2009). Although residential development poses a future potential risk, the present landowner has no current plans to develop the property in a fashion that would compromise the ability of the site to support P. figuratus. Road management activities on the adjacent paved road have the potential to directly damage plants or the habitat. Activities such as ditching or culvert placement could alter the hydrological regime of the vernal pool to the detriment of P. figuratus, although the long-term effects are difficult to predict (M. Fairbarns and M. Miller, pers. comm. 2009). Climate change effects are also unknown, although climate change could have a devastating impact on this vernal pool habitat. Small shallow pools such as those which support P. figuratus are vulnerable to changes in precipitation and evaporation rates, as these determine the duration of continuous inundation, the frequency of inundation events suited to the reproduction of vernal pool species, and the seasonal distribution of inundation (Pyke 2005). Changes to spring and early summer precipitation patterns could alter the habitat or lead to a whole-scale habitat shift (i.e., loss of the vernal pool habitat), as well result in physiological stresses, reduced germination and fitness, and reduced population viability for P. figuratus (M. Fairbarns and M. Miller, pers. comm. 2009). |
| Trend (in population, range, area occupied, and/or condition of occurrences) | |
| Short-Term Trend: | U = Unknown |
| Comments: | The 10-year population trend is unknown. Prior to 2005, no individuals had been observed on Hornby Island since 1986. However, the population was not regularly surveyed during this interval, and the available data are insufficient for estimating short-term population trends (COSEWIC 2008). The site where Fragrant Popcornflower was most recently observed (in 2005) is currently dominated by invasive grasses and forbs. California Oatgrass, the leading native grass species, is very scarce although it may have been the dominant plant prior to the arrival of exotic species (M. Fairbarns and M. Miller, pers. comm. 2009). |
| Long-Term Trend: | A = Decline of >90% |
| Comments: | Population size has declined within the last century. Although the historical population size in Canada is not known, the existence of several collection records from the coastal plains of southeastern Vancouver Island and the Gulf Islands is strong evidence that this species, while likely never common, was once significantly more abundant than at present . The historical range of Plagiobothrys figuratus encompasses a broad mosaic of maritime meadows, coastal bluffs, grasslands, and wet meadows within Garry oak and associated ecosystems. During the past century, this environment has been substantially altered by urbanization, land development, and fire suppression, to the point where only an estimated 1-5 % remains in a near-natural (i.e., pre-contact) condition (Fuchs 2001, Lea 2006). Despite ongoing efforts to protect what is left of this system, most remnant P. figuratus habitat remains under threat from continued urban development (COSEWIC 2008). |
| Other Factors | |
| Intrinsic Vulnerability: | A=Highly vulnerable |
| Comments: | The biology and demography of this species in Canada have not been investigated. Nevertheless, intrinsic vulnerability is considered "high" on the grounds (Master et al. 2009) that, within its known range in British Columbia, it is known to reproduce infrequently and has low fecundity such that populations are very slow to recover from decreases in abundance; it exhibitis limited dispersal capability such that extirpated populations are unlikely to become reestablished through natural recolonization (unaided by humans); and ecosystem occurrences are highly susceptible to changes in composition and structure that rarely if ever are reversed through natural processes even over substantial time periods. Other factors may further limit its viability, including: (1) potentially poor competitive ability, especially with respect to invasive alien species; (2) an annual life cycle that is dependent on winter/spring rains, and hence a possible predisposition to demographic failure if the spring/summer drought arrives early; (3) its very small area of physical occupancy which leaves it susceptible to chance events and small-scale disturbance; and (4) its small population size and highly fragmentated distribution which may reduce its genetic diversity and limit the potential for local rescue effects (M. Fairbarns and M. MIller, pers. comm. 2009). |
| Environmental Specificity: | B=Narrow. Specialist or community with key requirements common. |
| Comments: | Plagiobothrys figuratus occurs at low elevations in moist soils. Across its range, it is found in a range of vernally wet habitats including vernal pools, wetland prairies, ditches, and seasonally flooded fields and meadows. In British Columbia, P. figuratus is restricted to vernally wet habitats within the Coastal Douglas-fir biogeoclimatic zone (Moist Maritime subzone). This zone features a Mediterranean-like climate with warm, dry summers and mild, wet winters. Summer drought is an important climatic feature (COSEWIC 2008). |
| Other Rank Considerations: | The BC range currently makes up 100% of the Canadian range but less than one percent of the species' total North American range. The probability of a rescue effect is low. |
| Information Gaps | |
| Research Needs: | Current knowledge of Plagiobothrys figuratus is limited to general autecological characteristics and habitat preferences. The population dynamics have not been studied. For example, it is not known how large the population must be to be self-sustaining. Likewise, there is no information on the pollination mechanism or whether the population is limited by pollination. Responses to management activities such as invasive species removal are unknown. One important knowledge gap concerns the present viability of the soil seed bank at the Hornby Island site, as no plants have been observed here since 2005. The survival of the Canadian population may depend on the existence of a viable seed bank at this site. If any viable seeds do remain, it would be beneficial to know what conditions are necessary for successful germination and establishment. What biotic and abiotic factors are currently inhibiting germination, flowering, and seed set? Are there management techniques available to aid recruitment? |
| Inventory Needs: | Annual inventory of the Hornby Island site is urgently needed to determine the status of the last known occurrence. Searches of all potential and historical Plagiobothrys figuratus habitats on Vancouver Island and the Gulf Islands have not been completed. For example, the species was known historically from Comox, but this area has not been surveyed recently (COSEWIC 2008). So much of the best habitat on southeastern Vancouver Island and Gulf Islands has now been lost to urbanisation that the probability of finding new occurrences, or rediscovering historical occurrences, is very low; nevertheless, there is still a slim chance that additional surveys could yield positive results. |
| Stewardship | |
| Protection: | Measures should be taken to protect the last documented site from land conversion and any other imminent, external threats resulting from human activities. Protection for sites on private property can be achieved through a variety of mechanisms including voluntary stewardship agreements, conservation covenants, and purchase from willing sellers (M. Fairbarns and M. Miller, pers. comm. 2009). |
| Management: | A SARA-compliant recovery strategy, which identifies management needs of Plagiobothrys figuratus, is currently being drafted by the Garry Oak Ecosystems Recovery Team (M. Fairbarns and M. Miller, pers. comm. 2009). GOERT should be consulted prior to undertaking any management activities for this species. At the existing site as well as at proposed (re)introduction sites, management emphasis will be on ensuring proper environmental conditions for population persistence and growth. Site-specific and regional plans will focus on achieving a significant level of control over invasive alien species (and encroaching woody species), ensuring that critical hydrologic processes are intact, and improving landscape connectivity between potential recovery sites. The possible dependence of this species on seasonal (winter/spring) inundation may call for special management. |
| Version | |
| Author: | M. Miller and M. Donovan |
| Date: | August 21, 2013 |
| References | |
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COSEWIC. 2008b. COSEWIC assessment and status report on the fragrant popcornflower Plagiobothrys figuratus in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. vi + 23 pp.(www.sararegistry.gc.ca/status/status_e.cfm).
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Lea, T. 2006. Historical Garry Oak Ecosystems of Vancouver Island, British Columbia, pre-European Contact to the Present. Davidsonia 17(2):34-50. http://www.davidsonia.org/bc_garryoak
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Master, L., D. Faber-Langendoen, R. Bittman, G.A. Hammerson, B. Heidel, J. Nichols, L. Ramsay, and A. Tomaino. 2009. NatureServe conservation status assessments: factors for assessing extinction risk. NatureServe, Arlington, VA.
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Parks Canada Agency. 2013f. Recovery Strategy for the Fragrant Popcornflower (Plagiobothrys figuratus) in Canada. Species at Risk Act Recovery Strategy Series. Parks Canada Agency, Ottawa. vi + 19 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. 2013. Conservation Status Report: Plagiobothrys figuratus var. figuratus. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Jun 7, 2026).