Mountain holly fern (Polystichum scopulinum) COSEWIC assessment and status report: chapter 5
Habitat
Habitat requirements
In North America, P. scopulinum is restricted to sites with ferromagnesian or ultramafic rock outcrops (Figure 3; Kruckeberg 1969; Wagner 1993). Although a number of ultramafic rock outcrops occur in western British Columbia, only the ultramafic (olivine clinopyroxenite) band (at elevations of 978 to 1768 m) between Olivine Mountain and Grasshopper Mountain in the Tulameen River valley supports P. scopulinum. These slopes have a typically depauperate ultramafic flora and tree cover. This is in contrast to the dense surrounding montane forests dominated by Pseudotsuga menziesii. Conspicuous species on the slopes include: Pinus contorta, P. albicaulis, Aspidotis densa, P. kruckebergii, Juniperus communis, Sedum lanceolatum, Senecio streptanthifolius and Arctostaphylos uva-ursi. In Quebec, P. scopulinum is restricted to the southerly slopes of the Vallée du Diable, on the eastern flank of Mont Albert, at an elevation of 800 to 900 m. Ultamafic rock types in this area includeserpentinite, dunite and pyroxenite. The flora is similarly depauperate, with Picea mariana, Betula glandulosa, Ledum groenlandicum, Vaccinium vitis-idaea and Potentilla fruticosabeing the predominant species. Other associates include local serpentine endemics such as Minuartia marcescens, Salix chlorolepis and Solidago simplex subsp. simplex var. chlorolepis, as well as western disjuncts such as Adiantum aleuticum and Aspidotis densa. The original locality description for the Newfoundland occurrence was given as “southerly slopes of dry serpentine ridge.”
Trends
At the British Columbia sites, habitat trends are mainly dependent on development activities. The latter area is being actively logged and mining exploration occurs sporadically. The largest population on Britton Creek would be especially susceptible to such activities. In Quebec, the population on Mount Albert seems stable and is protected from development activities. No specific information is available for the North Arm Mountain area locality in Newfoundland.
Protection/ownership
There is no specific legislation for the protection of rare and endangered vascular plants in British Columbia. The population in the Tulameen River area of British Columbia is on public land but is not part of a protected area. It is conceivable that this area could qualify as an ecological reserve but this status has yet to be proposed. In Quebec, P. scopulinum has been legally designated as "Threatened" (Loi sur les espèces menacées ou vulnérables, Gouvernement du Québec 1993). The habitat of the species is located in Parc de la Gaspésie, and is legally protected. The collecting of P. scopulinum and the modification of its habitat is forbidden and subject to legal prosecution. Ownership of the North Arm Mountain locality area has not yet been determined.