BC Conservation Data Centre: Conservation Status Report
Apodemia mormo
Mormon Metalmark
| Scientific Name: | Apodemia mormo |
|---|---|
| English Name: | Mormon Metalmark |
| Provincial Status Summary | |
| Status: | S1S2 |
| Date Status Assigned: | February 04, 2020 |
| Date Last Reviewed: | February 04, 2020 |
| Reasons: | Mormon Metalmark is at the northernmost limit of its range, has significant threats to its habitats, and is at low population numbers. The population was considered to be extirpated from the southern Okanagan Valley; however three new occurrences have been discovered near Osoyoos (2009) and Vaseux Creek (2017). |
| Range | |
| Range Extent: | C = 250-1,000 square km |
| Range Extent Comments: |
2020: CDC calculation is approximately 750km2, which includes the range extension to Vaseaux Creek. 2012 CDC calcuation of mapped occurrences (using convex hull), is 468 km2. [~818 w/Vaseux Ck. 2017] The Mormon Metalmark is known from current and existing populations in the sagebrush steppe in the Bunchgrass Biogeoclimatic Zone within the Similkameen River drainage and historically from the Okanagan Valley. The bunchgrass subzone covers approximately 117 square kilometres in the Similkameen drainage and approximately 249 square kilometres in the Okanagan. Combined the BC range extent for the Mormon Metalmark is 366 square kilometres (COSEWIC 2002c).The range extent of Apodemia mormo, including the south Okanagan and the lower Similkameen River valley, is estimated at 366 km2. Mormon Metalmark habitat includes hillsides, slopes and embankments with sandy or gravelly soils and moderate to high densities of rabbitbrush (E. nauseosus) and snow buckwheat (E. niveum). Larvae require buckwheat for feeding and may require buckwheat stems or leaf litter for hibernating. Adults require mature buckwheat for egg laying and flowering snow buckwheat and rabbitbrush for nectaring (COSEWIC 2002). All known sites occur in the Bunchgrass Biogeoclimatic Zone at elevations below 520 meters ASL (O. Dyer, pers. comm.). |
| Area of Occupancy (km2): | E = 26-125 |
| Area of Occupancy Comments: |
2012 CDC calculation = 26 x 4km3 = 104km2 Patch size of occupied sites in BC vary from 0.01 ha to 1.5 ha. Consistently occupied patches generally are greater than 0.5 ha. Most of the habitats within this range are likely unsuitable for the Mormon Metalmark and it is estimated that the total suitable habitat is approximately 50 hectares (COSEWIC 2002c).The area of occupancy is approximately eight hectares total, at each of the 15 known colonies (St. John 2003). The linear distance of occupancy ranges from 20 metres to 100 metres, depending on the site (Heron, pers. obs.). |
| Occurrences & Population | |
| Number of Occurrences: | BC = 6 - 80 |
| Comments: |
There are at least 16 occurrences known; a range in the number is used to capture the likelyhood that there are undetected locations. 2017: a new occurrence was discovered at Vaseaux Creek (T. McIntosh, pers. comm. 2017). 2009: there were 2 new observations, northwest of Osoyoos, which is a range expansion to the east. 2004:BC population occupies (2004) approximately 15 patches at 4 sites, separated by distances > 5 km. Only 1 of the 4 sites has a well-connected meta-population structure (O. Dyer; D. St.John; B. White, pers. comm.). Four locations are known for Apodemia mormo, all throughout the lower Similkameen River valley in the Keremeos area. There are historic records of the species in the southern Okanagan valley, over 50 years old. Twenty-two occupied habitat patches, totaling ~15 hectares in the Similkameen river valley are known (BCMOE 2004), constituting four locations for the species. An occupied habitat patch is an area of contiguous habitat (see section 6.1), generally > 0.1 hectare, with occurrences of adult Mormon Metalmarks between 1995 and 2004. Additional occupied habitat likely exists but is not known due to incomplete knowledge of the species distribution. |
| Number of Occurrences with Good Viability / Ecological Integrity: | B = 1 - 3 |
| Comments: | Only 1 location has a well-connected meta-population structure. This site is within the borders of the town of Keremeos and the EO has four colonies within the location. Habitat patch separation distances: Metalmarks move only 49m to 64m, respectively for males and females, with 600m maximum movements (Arnold and Powell 1983). Therefore, well-connected habitat patches should be less than 600 m (estimated) apart and preferably less than 100m apart within a site. Note that low quality habitat (sparse individual or small clusters of snow buckwheat and/or rabbitbrush) is difficult to map but appears to be reasonably abundant and may be important for dispersal between discreet habitat patches.The four locations are all threatened by roadside maintenance activities, fragmentation, vegetation ingrowth and development. None of the areas are protected. |
| Number of Occurrences Appropriately Protected & Managed: | A = None |
| Comments: | All locations are not protected, although some locations are known to occur on government (municipal or provincial) lands. The BC Ministry of Transportation and Highways is believed to own lands with some populations. One patch within a location is known from land owned by the town of Keremeos, but this locality is not protected. Land ownership overall is unknown. |
| Population Size: | E = 2,500 - 10,000 individuals |
| Comments: |
20014: Estimated 3,000 at minimum (COSEWIC 2014o) 2011: "The BC population of the Mormon metalmark survives at low numbers (estimated as approximately 2000 individuals; S. Desjardins unpublished)" (Crawford et al. 2011). 2000-2006: there is information on populations at each of the four known sites, from surveys conducted from 2000 to 2006 (Dyer, pers. comm.; Desjardins, pers. comm., St. John, pers. comm., White, pers. comm., Heron, pers. comm.). The information in these surveys does not quantify the population at each site, but instead records the number of observations within a day. Many of the sites have > 50 individuals seen on a given day of surveys. This information has not been converted into a known population size at a given location. |
| Threats (to population, occurrences, or area affected) | |
| Degree of Threat: | AB = Very high - high |
| Comments: |
2013: Very High- High: the locations are not properly managed, the species will likely be extirpated from that location. Most of the locations known for this species are from steep gravel and sand roadside embankments that are periodically disturbed from erosion. Should highway roadside expansion or vegetation management occur populations will likely be extirpated.Apodemia mormo is at the northernmost extension of its global range in Canada, making it more susceptible to climatic extremes that cause flowering failure in nectar sources, local outbreaks of disease, predator and parasitoid populations, and the localized application of pesticides (St. John 2003). The following threats to Mormon metalmark populations are listed in order of severity: 1. Construction and maintenance activities along transportation and utility corridors. This threat applies to all locations for the species, and is the primary overall threat to the species. All known locations are adjacent to roadsides and transportation corridors, and there may be However, these activities may also create new habitat for food plants. 2. Agricultural or urban development and gravel quarrying is considered a secondary threat to all four populations. The larval and nectar food plants occur within areas under development pressure, and the overall decrease in available habitat contributes to the decline of the species. In addition, the gravel sites where the species is known to occur are favourable places from which to remove road construction materials. 3. All terrain vehicle traffic appears to be a threat at two of the four known locations. Gravel slopes and embankments are favourable locations for all terrain vehicle use, and lead to erosion and slope instability, as well as direct destruction of larval and nectar food plants. At one site the all terrain vehicle traffic appears to be confined to a designated, but well used path, and with appropriate signage this impact could likely be minimized. 4. Disposal of unwanted debris including tree prunings (woody stems and leaves, grass cuttings and other forms of organic cuttings) and garbage. At least three of the known locations have evidence of vegetation deposition, either from private citizens or from roadside maintenance activities. The deposit of debris can impact foodplants through direct mortality (deposited directly on foodplants), but also indirectly prevents the establishment of new foodplants through covering exposed soil and slow rotting of organic debris. 5. Miscellaneous threats include the planting of roadside shrubbery and ornamental plants, and the subsequent irrigation of these ornamental plants along one roadside site. 6. Natural processes such as wild fires have affected three sites and pose a potential threat locally, where habitat is seriously fragmented. 7. Other potential threats include climatic change and variability, noxious weeds leading to embankment stabilization, intensive grazing of foodplants and consequential trampling of foodplants, and indirect harm to foodplants as a result of pesticide use (St. John 2003). Competition of invasive weed species may impact larval and nectar food plants (St. John 2003). Development on private lands and agricultural practices such as pesticide and grazing, disposal of prunings and other garden waste, planting and irrigating habitats and roadside maintenance activities (St. John 2003). |
| Trend (in population, range, area occupied, and/or condition of occurrences) | |
| Short-Term Trend: | U = Unknown |
| Comments: | Assessing the habitat trends is difficult and unclear. Both the lower Similkameen River valley and southern Okanagan valley have been extensively modified by urban/rural/agricultural development over the past century, with more rapid development in the past ten years. The introduction of invasive weed species may be displacing the larval and nectar food plants (St. John 2003). Approximately 366 km2 of the sagebrush steppe remains within the south Okanagan and lower Similkameen river valleys (St. John 2003). This species currently uses microsites within three types of natural biophysical habitat units (Lea et al. 1995). Two units, barren habitat and sagebrush needle-and-thread grass habitat, have decreased in area by 45% and 54% respectively, due to habitat loss and alteration (Lea et al. in prep). The third unit, Bluebunch wheatgrass - Sandberg's bluegrass on deep soil has not decreased significantly. This species is extirpated from the Okanagan drainage, where it likely occurred mainly in antelope-brush needle-and-thread grass habitat, which has decreased in area by 62%. Metalmarks also occur in two human modified units, gravel pit and dry pasture, which have increased in area due to disturbance by human activities. Known colonies mainly use disturbed microsites along transportation and utility corridors, which have increased in abundance due to initial construction but can be adversely impacted during maintenance activities. Habitat quality and fragmentation have not been quantified but likely influence distribution. |
| Long-Term Trend: | E = Decline of 30-50% |
| Comments: | The available habitat for this species has decreased signficantly in the past one hundred years. Agricultural land conversion and urban expansion, alien invasive plant species encroachment has contributed to the long term degradation of the ecosystem/habitat in which the Mormon Metalmark is known to occur. The populations in the Okanagan Valley have been extirpated. Assessing the habitat trends is difficult. Both the lower Similkameen River valley and southern Okanagan valley have been extensively modified by urban/rural/agricultural development over the past century, with more rapid development in the past ten years. The introduction of invasive weed species may be displacing the larval and nectar food plants (St. John 2003). |
| Other Factors | |
| Intrinsic Vulnerability: | B=Moderately vulnerable |
| Comments: | Due to the low number of known populations of this species in Canada, a site is unlikely to be recolonized following extirpation. Populations fluctuate greatly at each of the known sites, and parasitoids have been known to cause decreases in populations (St. John 2003). |
| Environmental Specificity: | A=Very narrow. Specialist or community with key requirements scarce. |
| Comments: | Apodemia mormo depends on Buckwheat (Eriogonum nudum auriculatum Benth.) as the larval foodplant. Adult butterflies require common rabbitbrush Ericameria nauseosus Pall. Both these larval foodplants occur on roadside embankments, gravel bars, or similar habitat types. |
| Other Rank Considerations: | |
| Information Gaps | |
| Research Needs: | Research is required to more accurately quantify specific habitat requirements including food plant density and patch size; species' dispersal capabilities, reproductive success and population viability; 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 utility and transportation corridor expansion and maintenance, aggregate quarrying, invasive weeds, adjacent property management and wild fire. Research is also required to assess potential threats from pesticide use and heavy livestock grazing on all life stages. |
| Inventory Needs: | Inventory of the lower Simillkamenn River valley and southern Okanagan valleys, targeting rocky and gravelly slopes and embankments with rabbitbrush and buckwheat. Inventory of potential habitat, population size and distribution is incomplete and requires additional surveys. Monitoring of population parameters including fluctuations in size, emigration, recruitment, persistence, dispersal distance, etc. is not available. A long term monitoring program must be established and implemented. |
| Stewardship | |
| Protection: | None of the known sites are protected. Four sites are on privately owned land, one site is on Indian Reserve No. 8 (Skemeoskuakin) and ten sites are on transportaion corridor right-of-ways managed by BC Ministry of Transportation and Highways (St. John 2003). |
| Management: | Best management practices guidelines for right-of-way maintenance crews, private landowners, ranchers and local citizens. |
| Version | |
| Author: | Heron, Jennifer, L. Ramsay, L. Gelling |
| Date: | March 06, 2020 |
| References | |
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Environment and Climate Change Canada. 2017. Recovery Strategy for the Mormon Metalmark (Apodemia mormo), Southern Mountain Population, in Canada. Species at Risk Act Recovery Strategy Series. Environment and Climate Change Canada, Ottawa. 2 parts, 36 pp. + 14 pp. |
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Arnold, R.A. and J. A. Powell. 1983. Apodemia mormo langei. Ch. 6 In Ecological studies of six endangered butterflies (Lepidoptera: Lycaenidae): Island biogeography, patch dynamics and design of habitat preserves. Univ. Cal. Publ. Entomol. 99: 1 - 161.
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B.C. Ministry of Environment (BCMOE). 2004. Working files in Arcview, based on inventory. Penticton, BC.
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COSEWIC. 2002c. COSEWIC assessment and update status report on the mormon metalmark Apodemia mormo in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. vii + 22 pp.
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COSEWIC. 2014o. COSEWIC assessment and status report on the Mormon Metalmark Apodemia mormo in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. xiv + 61 pp.
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Crawford, L.A., S. Desjardins and N. Keyghobadi. 2011. Fine-scale genetic structure of an endangered population of the Mormon metalmark butterfly (Apodemia mormo)revealed using AFLPs. Conserv Genet. 12:991-1001
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Lea, E.C., R.E. Maxwell, and A. Swanson. 1998. Biophysical Habitat Units of the South Okanagan Study Area. Working Report. British Columbia Ministry of Environment, Lands, and Parks. Victoria.
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Lea, T. 2008. Historical (pre-settlement) ecosystems of the Okanagan Valley and Lower Similkameen Valley of British Columbia - pre-European contact to the present. Davidsonia 19(1): 3-36.
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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. 2020. Conservation Status Report: Apodemia mormo. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Jun 13, 2026).