BC Conservation Data Centre: Conservation Status Report
Myosurus apetalus var. borealis
bristly mousetail
| Scientific Name: | Myosurus apetalus var. borealis |
|---|---|
| Scientific Name Synonyms: |
Myosurus aristatus
|
| English Name: | bristly mousetail |
| Provincial Status Summary | |
| Status: | S4 |
| Date Status Assigned: | April 29, 2015 |
| Date Last Reviewed: | April 30, 2019 |
| Reasons: | Myosurus apetalus var. borealis occurs in at least eleven discrete locations (with many others expected) over a large area (ca. 13,000 square km) in south-central British Columbia, with over 20,000 individual plants. It does not appear to be intrinsically vulnerable, is moderately specific in its habitat preference, and is overall only slightly threatened. |
| Range | |
| Range Extent: | E = 5,000-20,000 square km |
| Range Extent Comments: | Myosurus apetalus var. borealis has a range of more than 13,000 square km (using GIS tools) and grows across south central British Columbia from Osoyoos in the south, north to Merritt, Lytton, Ashcroft, Kamloops and Westwold. |
| Area of Occupancy (km2): | AC = 1-5 |
| Area of Occupancy Comments: | Myosurus apetalus var. borealis occupies at least 3,000 square m in British Columbia. |
| Occurrences & Population | |
| Number of Occurrences: | BC = 6 - 80 |
| Comments: | Eleven occurrences are known, but potential habitat for this species is abundant and additional populations almost certainly occur. |
| Number of Occurrences with Good Viability / Ecological Integrity: | C = 4 - 12 |
| Comments: | Little information is available that can be used to rank all known occurrences, but at least four populations (ca. 30% of all reported sites) are estimated to have good viability. |
| Number of Occurrences Appropriately Protected & Managed: | B = 1 - 3 |
| Comments: | Though it is unknown if they are effectively protected, two occurrences are located at Painted Bluffs Park, near Kamloops and at Epsom Provincial Park, south of Ashcroft. A third population may occur within Anarchist Protected Area, but confirmation is not possible without more precise location information. |
| Population Size: | F = 10,000 - 100,000 individuals |
| Comments: | Well over 20,000 plants have been reported. |
| Threats (to population, occurrences, or area affected) | |
| Degree of Threat: | Widespread, low-severity threat |
| Comments: | This species has likely been impacted by all of the following: residential and recreational development, overgrazing, forest encroachment, road and trail development and off-road recreation use, all of which have resulted in irreversible losses of native grassland species, throughout south-central B.C. The primary threat however, are current range practices which involve cattle concentrating around alkaline watering holes and trampling vegetation and activities which disrupt spring moisture rendering habitats more amenable to weed encroachment. This threat is probably not adversely affecting a large proportion of the population and other associates in such habitats are probably much more sensitive than Myosurus. |
| Trend (in population, range, area occupied, and/or condition of occurrences) | |
| Short-Term Trend: | G = Relatively Stable (<=10% change) |
| Comments: | Populations in B.C. have not been monitored, and therefore short term trends are unknown, but since populations of this species are only slightly threatened and can tolerate some degree of disturbance, the short-term trend is expected to be stable. Annual population fluctuation is probably normal for this annual plant, with the potential for large changes in different climatic scenarios. However, unlike some annual species, Lomer (pers. comm. 2007) usually sees large populations, despite different climatic conditions each year. |
| Long-Term Trend: | U = Unknown |
| Comments: | Insufficient historical information is available to determine long-term trends. However, it has been known in BC since 1875 and has been verified in that location recently suggesting the trend may be more or less stable. This species can also opportunistically colonize waste areas near urban developements where a suitable hydrological regime prevails. On the other hand, Intensive land in the early part of the 20th century could have reduced suitable habitat. |
| Other Factors | |
| Intrinsic Vulnerability: | C=Not intrinsically vulnerable |
| Comments: | The species is able to opportunistically invade waste areas near urban developments, suggesting that it is not intrinsically vulnerable. Large populations are often observed. |
| Environmental Specificity: | C=Moderate. Generalist or community with some key requirements scarce. |
| Comments: | Myosurus apetalus var. borealis grows in vernally moist meadows, streambanks and pools, and bare soil in sagebrush within the Bunchgrass and Ponderosa Pine biogeoclimatic zones of British Columbia, which occupy a relatively small area of the province. However, these vernally moist habitats are not limiting features on the landscape. This subspecies can also be found in gravelly waste areas near urban developments (so long as there is spring moisture). |
| Other Rank Considerations: | |
| Information Gaps | |
| Research Needs: | |
| Inventory Needs: | Directed surveys of known sites to evaluate their status, and a thorough survey of vernally moist meadows, streambanks and pools in the steppe zone to determine if more populations exist than are currently known. |
| Stewardship | |
| Protection: | |
| Management: | |
| Version | |
| Author: | Donovan, M. and J. L. Penny |
| Date: | October 24, 2007 |
| References | |
|
British Columbia Conservation Data Centre. Botany Program. 2000. Database containing records of rare plant collections and observations in the province of British Columbia.
|
|
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. 2007. Conservation Status Report: Myosurus apetalus var. borealis. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Jun 7, 2026).