BC Conservation Data Centre: Conservation Status Report
Bartramia aprica
rigid apple moss
| Scientific Name: | Bartramia aprica |
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| Scientific Name Synonyms: |
Bartramia stricta
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| English Name: | rigid apple moss |
| Provincial Status Summary | |
| Status: | S2 |
| Date Status Assigned: | April 30, 2024 |
| Date Last Reviewed: | April 30, 2024 |
| Reasons: | In BC, there are four extant occurrences of Bartramia stricta. Two of these are protected and are considered to have good viability, and the status of two is unknown. A fifth population appears to be extirpated. Population size is estimated between 50 - 250 individuals. Area of occupancy based on a 2km x 2km grid analysis is 20 square kilometres. Current trends suggest a loss of 20% of the BC population and long term trends are estimated to be a decline of 25% - 50%. The scope and immediacy of threats to B. stricta are high, but severity is moderate if populations can recover in 50 - 100 years. Habitat is facing increasing threat from urbanization and encroachment by competing vegetation in the absence of fire. |
| Range | |
| Range Extent: | C = 250-1,000 square km |
| Range Extent Comments: | In BC, Bartramia stricta is limited to the dry Coastal Douglas-fir zone on southeastern Vancouver Island, where occurrences are limited to the extent of grassy rock outcrops associated with Quercus garryana, extending from SW of Victoria to Lasqueti and possibly Hornby Island, representing an historical and existing area of 250 - 1,000 square kilometres. These populations occur at the northernmost edge of the range of the species. |
| Area of Occupancy (km2): | D = 6-25 |
| Area of Occupancy Comments: | Using dimensions of "patches" reported by Belland (1997), Byrne et al. (2005), and the BC Bryophyte Recovery Team (2007), populations of Bartramia stricta at Nanoose Hill and Mary Hill are estimated to occupy 0.09 square metres and 0.08 square metres, respectively, a total of 0.17 square metres. No population data are available for the occurrences on Lasqueti Island, Sidney Island, and at Pedder Bay (BC Bryophyte Recovery Team 2007). Using a 2 km x 2 km grid analysis, this species occupies 5 grids (20 sq km). |
| Occurrences & Population | |
| Number of Occurrences: | AB = 1 - 20 |
| Comments: | Five occurrences of Bartramia stricta are known from BC: Nanoose Hill, Lasqueti Island, Sidney Island, Mary Hill, and Pedder Bay (Belland 1997; Byrne et al. 2005; BC Bryophyte Recovery Team 2007). The Pedder Bay population was first discovered by W.B. Schofield in 1974 but has not been relocated and may have been extirpated by invasive vascular plants (Belland 1997; R. Belland, pers. comm. 2007). The Lasqueti Island and Sidney Island populations were discovered in 2002 by K. Sadler (BC Bryophyte Recovery Team 2007). It is likely that other populations may exist, particularly around the perimeter of urbanized areas where development has been less intense. Further search effort has been recommended by the BC Bryophyte Recovery Team (2007). |
| Number of Occurrences with Good Viability / Ecological Integrity: | B = 1 - 3 |
| Comments: | Two populations are estimated to have good viability. Those at Nanoose Hill and Mary Hill appear to be large enough and are being protected by the land owner (Byrne et al. 2005; McIntosh 2007). The population at Pedder Bay appears to have been extirpated, and no current information is available for the populations on Lasqueti and Sidney islands (BC Bryophyte Recovery Team 2007). |
| Number of Occurrences Appropriately Protected & Managed: | B = 1 - 3 |
| Comments: | Two occurrences (Nanoose Hill, Mary Hill) are on DND land, and DND is protecting habitat for Bartramia stricta through voluntary stewardship activities such as controlling access, maintaining habitat structure, and monitoring populations. The population on Lasqueti Island occurs within an Ecological Reserve. No information is available regarding protection of populations on Sidney Island or at Pedder Bay and these two occurrences are currently not considered protected (BC Bryophyte Recovery Team 2007). |
| Population Size: | BC = 50 - 1,000 individuals |
| Comments: | Patches or sods of bryophytes may originate from a single spore or vegetative propagule and by convention each is counted here as an individual plant (Hallingback and Hodgetts 2000). Using numbers of patches reported by Belland (1997), Byrne et al. (2005), and the BC Bryophyte Recovery Team (2007), populations of Bartramia stricta at Nanoose Hill and Mary Hill are estimated to be 125 - 183 and 44, respectively, a total of 169 - 227. No population data are available for the sites on Lasqueti Island, Sidney Island, or at Pedder Bay (BC Bryophyte Recovery Team 2007). |
| Threats (to population, occurrences, or area affected) | |
| Degree of Threat: | Substantial, non-imminent threat |
| Comments: | The scope of threats to Bartramia stricta is high, severity is moderate and immediacy is unknown. Region-wide habitat loss, spread of exotic species, and fire suppression are the most serious threats, particularly to those populations with small numbers of plants. The Quercus garryana - Arbutus menziesii - Pseudotsuga menziesii woodland and savanna habitat in which B. stricta occurs is relatively extensive but has been decimated by livestock grazing, urbanization, and fire suppression. Less than 5% of this habitat exists in undisturbed condition, making it one of the most imperiled natural communities in Canada (Fuchs 2001; BC Bryophyte Recovery Team 2007). These sites have no agricultural potential and are unsuitable for most forms of commercial development, but their value for residential development is increasing because of the rapidly expanding population around Victoria and Nanaimo. Potential habitat in public parks is at risk because of heavy recreational use and the absence of habitat management plans. Fire supression has enabled exotic species (e.g., Cytisus scoparius, Daphne laureola, Anthoxanthum odoratum, Hypochaeris radicata) and native woody species (e.g., Pseudotsuga menziesii, Symphoricarpos albus) to invade and shade out habitat. Increased shade and moisture availability enables native mosses such as Dicranum scoparium and Rhytidiadelphus triquetrus to invade. These species form large sods that overrun those of exposed rock outcrops and savannas. Encroachment by vascular plants has probably led to the extirpation of B. stricta at Pedder Bay (Belland 1997; BC Bryophyte Recovery Team 2007; J. Christy, pers. comm. 2008). |
| Trend (in population, range, area occupied, and/or condition of occurrences) | |
| Short-Term Trend: | F = Decline of 10-30% |
| Comments: | Population data reported by Belland (1997), Byrne et al. (2005), and the BC Bryophyte Recovery Team (2007) indicate a stable trend over the last 10 years at the two sites surveyed. Information is not available for the populations at Pedder Bay and Lasqueti Island. Belland (1997) and M. Ryan (pers. comm. in Belland 1997) feel that the Pedder Bay location is extirpated, thus representing a projected loss of 20% of the population. |
| Long-Term Trend: | E = Decline of 30-50% |
| Comments: | Trend over the last 200 years is estimated to be a moderate decline, but specific data on historical extent and losses are not available. Presumably Bartramia stricta survived thousands of years of aboriginal occupation and cultural burning practices, and available habitat was (and still is) relatively abundant. Since 1850, fire suppression, livestock grazing, urbanization, and competition from invading vascular plants have caused large declines in rare vascular plants that occur in the same habitat as B. stricta. However, in contrast to vascular plants, bryophytes are often able to persist in suitable microhabitats despite the presence of invasive exotic species or the loss of major ecosystem processes such as fire. Their small size and ability to grow in specialized habitats such as rock faces sometimes enable them to persist where native vascular plants cannot. |
| Other Factors | |
| Intrinsic Vulnerability: | U=Unknown |
| Comments: | Intrinsic vulnerability is unknown. Bartramia stricta is known to reproduce both sexually and vegetatively, and traits that could hinder dispersal and establishment are not evident. |
| Environmental Specificity: | B=Narrow. Specialist or community with key requirements common. |
| Comments: | Environmental specificity is narrow. Bartramia stricta is restricted to low elevation, dry, exposed and rocky savanna habitats with a Mediterranean climate. Available habitat is relatively abundant on southeastern Vancouver Island, however Bartramia stricta disappears if these habitats convert to shrubby or forest vegetation. |
| Other Rank Considerations: | In BC, Bartramia stricta occurs at the northern limit of its distribution in North America. The Canadian populations probably represent under 0.01% of its global distribution and abundance (Belland 1997; BC Bryophyte Recovery Team 2007). |
| Information Gaps | |
| Research Needs: | Detailed habitat requirements and the effects from competing vegetation are not well known. Because there is no evidence that Bartramia stricta was ever abundant or widespread in coastal BC, recovery efforts should focus on improving the viability of populations. Successful recovery will depend on a combination of research, habitat protection and management, and long-term population monitoring. Barriers to recovery of existing populations need to be identified and removed (BC Bryophyte Recovery Team 2007). |
| Inventory Needs: | Inventory is still required across the range of Bartramia stricta in BC, even though some areas already have been searched by bryologists.The populations on Lasqueti Island and Sidney Island need to be revisited and assessed. Sites surveyed by bryologists need to be compiled in order to focus new search efforts (BC Bryophyte Recovery Team 2007). Prospects for recovery will be enhanced if new and larger populations can be found (McIntosh 2007). Belland (1997) noted that at least 10 Quercus garryana sites have been fairly well surveyed (including Colwood, Royal Oak, William Head, Thetis Lake, Mount Tolmie, Clovelly Terrace, Mary Hill, Mount Maxwell, Mount Tzuhalem and Nanoose Hill), but much potential habitat remains unknown. An intensive inventory of all oak and cliff habitats on the southwestern BC coast is recommended, and will capture new occurrences of other species of bryophytes and vascular plants that occur in the same habitat (BC Bryophyte Recovery Team 2007). |
| Stewardship | |
| Protection: | DND has implemented protection plans for populations of Bartramia stricta at Nanoose Hill and Mary Hill. Because the Pedder Bay population is thought to have disappeared, there are no other opportunities for protection until the condition of the populations on Lasqueti Island and Sidney Island are assessed, or until new sites are found. |
| Management: | DND is managing habitat for Bartramia stricta at Nanoose Hill and Mary Hill by controlling access, maintaining habitat structure, and monitoring populations. Because future changes in DND funding or program needs may impair their management effectiveness, it is advisable to involve volunteer private-sector stewards in land management activities. In the case of a downturn in federal support, volunteer stewards could carry on with critical habitat management and monitoring to ensure the viability of B. stricta. |
| Version | |
| Author: | Christy, John A., J. L. Penny and S. Hartwell |
| Date: | February 18, 2010 |
| References | |
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Belland, R.J. 1997. Status Report on the Apple Moss Bartramia stricta Brid. in Canada. Rep. submitted to the Comm. on the Status of Endangered Wildl. in Can. Ottawa. 24pp.
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British Columbia Bryophyte Recovery Team and Garry Oak Ecosystems Recovery Team. 2007. Recovery strategy for the rigid apple moss (Bartramia stricta Bridel) in British Columbia. Prepared for the B.C. Minist. of Environ., Victoria, BC. 20pp.
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Byrne, L., N. Ayotte, and A. Robinson. 2005. Survey for rigid apple moss (Bartramia stricta) on Department of National Defence Land on Vancouver Island (CFMETR and Mary Hill) IRF Project #397. Report prepared for Natural Resources Canada and the Canadian Forest Service. 11pp.
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Fuchs, Marilyn A. 2001. Towards a Recovery Strategy for Garry Oak and Associated Ecosystems in Canada: Ecological Assessment and Literature Review. Tech. Rep. GBEI/EC-00-030. Environ. Can., Can. Wildl. Serv., Pac. and Yukon Region.
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Hallingbäck, T. and N. Hodgetts. 2000. Status survey and conservation action plan for bryophytes: mosses, liverworts, and hornworts. IUCN/SSC Bryophyte Specialist Group. Gland, Switzerland and Cambridge, UK. X+106 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. 2010. Conservation Status Report: Bartramia aprica. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Jun 17, 2026).