Frosted glass-whiskers (Sclerophora peronella) COSEWIC assessment and status report: chapter 5

Habitat

Habitat requirements

Sclerophora peronella has been found on bark and lignum of old deciduous trees such as Acer, Fagus, Fraxinus, Quercus, Sorbus, Tilia and Ulmus in humid and rather shaded situations, and more rarely on lignum of Alnus, Betula, Fagus, Populus, and Malus (Tibell 1999). Tibell also notes (pers. comm.) that “it usually occurs on wood of hardwoods--usually on decorticated parts in hollows of living trunks and more rarely on bark. It is often associated with old-growth forests, but also occurs in parklands and on the margins of old deciduous forests.”

According to Eric Peterson (pers. comm.), S. peronella “mainly grows on large trunks of old Quercus garryana in open savannas. One collection is from a large old Acer macrophyllum, and another is from a very odd habitat; a somewhat young Abies grandis (approximately 100 years old) within an old growth Douglas fir forest”. Describing the 14 collections he has made, Jouko Rikkinen (pers. comm.) says the species is “relatively common only on aged hardwoods in the Willamette Valley (Oregon). In other types of forests I only found a few small populations, mostly in riparian old-growth stands”. It should be noted that the region in Canada most similar in climate and vegetation to the Willamette Valley is the Puget Sound area of southeast Vancouver Island where Sclerophora peronella has not yet been found despite the earlier intensive collecting efforts of Noble (1982).

The specimen from British Columbia was corticolous (on bark) at the base of a large black cottonwood (Populus trichocarpa) in a rich, rather shady cottonwood stand. Both of the specimens from Nova Scotia were lignicolous on the exposed heartwood of living Acer rubrum growing in old-growth northern hardwood stands.

Sclerophora peronella is likely to be confined to maritime areas in Canada, owing to the frost sensitivity of its trentepohlian algal partner.

Trends

The availability of the habitat, environmentally stable older forests in coastal regions, is declining. For example in the Acadian Forest Region where it is currently known in Nova Scotia, little intact habitat remains, with logging cited as the main cause of habitat loss (World Wildlife Fund 2000).

British Columbia fares much better in this regard, as large tracts of older forest still remain. Although S. peronella may be known today from only one collection in a black poplar stand, the available data suggests that older coniferous and deciduous forests may both be considered suitable habitat for this species. However, because of the low numbers of specimens collected in Canada over the last 30 years, survival trends cannot be determined.

Protection/ownership

Both NS sites that presently have the lichen, the Sugarloaf Mountain and Margaree River sites, are Crown Land Wilderness Areas that are afforded official protected status by the province of Nova Scotia under the Wilderness Areas Act.

The site in BC that has the lichen, Kitsumkalum Lake site, is best described as a provincial forest service Recreational Reserve with a portion set aside as a demonstration forest for small scale logging, e.g., horse logging (K. Kriese, pers. comm.). There is nothing in the currently established objectives for this stand that protects the S. peronella site. 

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