A New Hotspot for Blue Felt Lichen (Pectenia plumbea) in Atlantic Canada

Yolanda F. Wiersma^1,*, Riley Hennifent¹, Justin Hodge², Dean Gillingham², Barry Francis², Francis Skeard², and R. Troy McMullin³

¹Department of Biology, Memorial University, St. John’s, NL A1C 5S7, Canada.²Qalipu First Nation Land Guardians, Corner Brook, NL A2H 2Z4, Canada. ³Canadian Museum of Nature, Ottawa, ON K2P 2R1, Canada. *Corresponding author.

Northeastern Naturalist, Volume 32, Issue 1 (2025): 103–113

First published early online: 29 March 2025

Abstract
Pectenia plumbea (Blue Felt Lichen) is a cyanolichen considered rare and at-risk in eastern North America. Most of the North American distribution is in the Canadian Atlantic provinces. More than 60% of the previously documented individual thalli were from the province of Nova Scotia. Here, we document a new location for this species on the island of Newfoundland and test whether number of thalli per tree is related to tree size and extent of coverage on the bole, and whether size of largest thallus on each tree is related to thalli abundance. Unique to other Newfoundland localities with P. plumbea, this site is inland in the central region of the province. We found over 1000 thalli on 102 trees. Unlike previous occurrences throughout Atlantic Canada, most of the individuals are on Populus tremuloides (Trembling Aspen). We found statistically significant relationships between tree diameter and number of thalli, and the length of the bole covered by P. plumbea and the number of thalli per tree. Trees with more thalli also had larger thalli, which suggests ideal growing conditions that could be further examined to delineate critical habitat for this species-at-risk. Finally, we document threats and identify future research needs to better understand this species’ habitat requirements.

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