Frosted glass-whiskers (Sclerophora peronella) COSEWIC assessment and status report: chapter 11

Summary of Status Report

Sclerophora peronella is known from fewer than 20 collections for all of North America, including one in British Columbia and two in Nova Scotia.  The remainder are collections from western Oregon. It is possible, however, that due to its minute size and only relatively recent discovery in North America, further fieldwork in Canada will result in the finding of additional localities. To date, S. Selva has searched a total of 76 forested sites in northeastern North America with an emphasis on Maine, New Brunswick, Nova Scotia, Prince Edward Island, southeastern Ontario and southwestern Quebec. No new sites were found beyond the original discoveries. New localities for other calicioid lichens were found, however, during recent targeted searches for S. peronella. Current indications are that S. peronella appears to be a very rare species in Canada and North America.

For the world as a whole, the species is considered rare to extremely rare throughout its range and is red listed in Austria (Hafellner 2000), Denmark, Sweden and Finland (Tibell 1999). It is declining in Italy (Nimis 2000), and is known from only single records or from only a few collections in Russia and several other European countries. 

Each of the Nova Scotia collections was examined and determined to have apothecia that were in good condition, containing spores that appeared to be viable; the apothecia also did not demonstrate any of the negative symptoms associated with air pollution or attack by parasites.  Given the sensitivity of this and other calicioid species to disturbance, it was clear that S. peronella was healthy at the two sites.  Likewise, the species at the collection site reported by Trevor Goward for British Columbia was also healthy. However, the health of such disparate populations is difficult to judge when the species is so small that it cannot be positively identified in the field, appears to be rare to extremely rare throughout its range, and has been encountered only once in each of two forest ecosystems.

Given the available data, S. peronella seems to prefer the ecological stability associated with mature and old-growth forests.  Unfortunately, according to a report from the World Wildlife Fund (2000) on the status of the Acadian forest in northeastern North America--within which it resides in Nova Scotia, little intact habitat remains in this ecoregion, with only about 3-5 percent of this forest in presettlement condition.  British Columbia fares much better in this regard, as large tracts of older forests still remain and undoubtedly harbour more populations of this rare species.

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