Erioderma pedicellatum

Last updated

Erioderma pedicellatum
Erioderma pedicellatum2.JPG
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Fungi
Division: Ascomycota
Class: Lecanoromycetes
Order: Peltigerales
Family: Pannariaceae
Genus: Erioderma
Species:
E. pedicellatum
Binomial name
Erioderma pedicellatum
(Hue) P.M.Jørg. (1972)
Synonyms
  • Pannaria pedicellataHue (1911) [2]

Erioderma pedicellatum is a medium-sized, foliose lichen in the family Pannariaceae, [3] commonly called the boreal felt lichen. It grows on trees in damp boreal forests along the Atlantic coast in Canada, as well as in southcentral Alaska, the Kamchatka Peninsula [4] [5] , and Norway [6] .

Contents

Description

Erioderma pedicellatum is a foliose cyanolichen with lobes 2–5 cm across, and occasionally reaching 12 cm in diameter. It has a distinctively fuzzy upper surface that is greyish-brown when dry, and slate-blue when moist. Its underside is white, and its edges usually curl upwards, giving it the appearance of having a white fringe. [7] [8] It differs from the two other North American species of Erioderma by lacking soredia, and by having small, reddish-brown apothecia on its upper surface. [7]

Taxonomy and naming

Erioderma pedicellatum was first collected in 1902 from Campobello Island, Charlotte County, New Brunswick, Canada, by William Gilson Farlow. [9] It was originally identified as a species of Pannaria and named Pannaria pedicellata by French botanist Auguste-Marie Hue. [10] It remained in this genus until 1972 when it was reexamined by the Norwegian botanist Per Magnus Jørgensen and placed in the genus Erioderma as Erioderma pedicellatum. [11] It is an unusual species within that genus, both because of its laminal (upper surface) apothecia (lacking in other Erioderma) and its boreal distribution. [10] Erioderma pedicellatum has also been incorrectly called E. boreale. [11]

Biology and ecology

Erioderma pedicellatum grows on mossy trunks and branches of trees on slopes in areas that have a constant supply of moisture, and are rich in Sphagnum moss. [8] It is usually found on balsam fir, occasionally on black spruce, and rarely on white spruce, red maple, or white birch. [8] It does not appear to grow directly on bare bark, and is usually found growing in association with the epiphytic liverwort Frullania asagrayana . [8] Old growth balsam fir boreal forests in wet areas of eastern Canada regenerate by gap replacement, which creates many forest stands of different ages, while still maintaining a full or partial canopy. [12] It appears that this diversity in forest stands age is necessary for a viable population of E. pedicellatum. [8] Natural dispersal of E. pedicellatum is evidently possible within these old-growth forests, but there are no known examples of E. pedicellatum establishing in stands previously clear-cut. [8]

A healthy, mature specimen of E. pedicellatum can grow at a rate of 11 to 14 mm per year, and populations of this lichen have a generation time of about 30 years. [8] The species sexually reproduces. [13] However, as with most lichen, considerable information in understanding E. pedicellatum biology is missing, especially information about its life stages. [14]

Scytonema cyanobacteria photobionts of this lichen make it particularly sensitive to acid rain and other atmospheric pollutants. [8] It requires relatively cool and moist oceanic climates, and an open canopy. It deteriorates rapidly on dead trees, or if habitat succession occurs that reduces, or increases light availability. [8] Altered micro-climatic conditions caused by extensive logging also causes E. pedicellatum to deteriorate. [8]

Symbiosis

Erioderma pedicellatum, like all lichens, is a symbiotic, in this instance between an ascomycete fungus and cyanobacteria of the genus Scytonema , and is therefore capable of fixing nitrogen. E. pedicellatum may also be part of second symbiosis with the epiphytic liverwort Frullania asagrayana . [15]

The symbiosis between the free-living Scytonema and the germinating ascomycete spores of E. pedicellatum is hypothesized to begin within the water sacs of Frullania asagrayana, where the fungal hyphae assimilates a cyanobacterium, and needs to develop for 5 to 10 years before it reaches a visible size. [8] The liverwort may also benefit from the nitrogen that is being fixed by the cyanolichen growing within it. [8] This complex relationship means that the ecological balance between E. pedicellatum and its cyanobacterial symbiont (Scytonema), its host tree, and (potentially) its liverwort nursemaid (Frullania asagrayana), is very delicate and easily impacted by logging, air pollution, and other factors. More information is needed to fully understand the symbiosis within E. pedicellatum. [15]

Distribution

Erioderma pedicellatum is distributed in the Northern Hemisphere. It can be found on both sides of the Atlantic and Pacific coastal regions.

Atlantic populations

Erioderma pedicellatum was once prevalent in Norway, Sweden, and the provinces of New Brunswick, Nova Scotia, and Newfoundland in Atlantic Canada. In Europe, it was first discovered in three nearby sites in the boreal rainforests of Norway (1938–39) and in five forested canyons in Värmland, Sweden (1941) [16] , but logging soon led to its extinction from all known European sites. [6] [17] [18] [8] However, during later intensive searches for this lichen, a few individuals were found in two new sites and one old site [6] , and a few thousand individuals were found in one site in Rendalen, eastern Norway. [19] [20]

In Canada, it is no longer found in New Brunswick, and as of 2009 there were fewer than 200 individuals known in Nova Scotia. [8] [21] In Newfoundland, it is estimated that there are between 15,000 to 20,000 individuals. The remaining habitat in Newfoundland is therefore critical for the global survival of this species. Lockyer's Waters and Hall’s Gullies on the Avalon Peninsula to the southeast, and Bay d'Espoir to the south, are three of the Newfoundland's most prolific rare lichen habitats, and are important for the conservation of E. pedicellatum. [22] The lichen was recorded as new to Quebec in 2022. [23]

Pacific populations

Recently, populations were discovered in Denali area of Alaska, and in the Kamchatka Peninsula of Russia, increasing the known range of the species, and is the first time the species has been observed in the Pacific region. [4] [15] While little is known about the population in Russia, the Alaskan population has been projected to be able to increase the global population to about 100,000 individuals based on statistical modeling (ie. projecting the population size based on the known number of individuals counted in a certain area of the site, quantifying known variables, and the actual size of the site.) [24] However, more research is needed on the Alaskan population to determine its population stability, as well as whether it is genetically distinct from the Atlantic populations, since the Alaskan population were found on white spruce twigs, a different type of tree usually associated with E. pedicellatum in Canada. The Canadian populations were also found mostly on trunks, as opposed to twigs. [25]

Conservation status

Lichen conservation is a growing field. [14] E. pedicellatum is currently listed as endangered by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) [8] and critically endangered by the International Union for Conservation of Nature (IUCN) since its last assessment in 2003. [1] No other lichen is listed by the IUCN. [26]

Protection

Two of the main populations of E. pedicellatum in Newfoundland are currently within protected areas: Jipujijkuei Kuespem Provincial Park, and the Lockyer’s Waters interim protected area, which was established specifically to protect this lichen. [8] The Bay du Nord Wilderness Area in Newfoundland also includes some populations of the lichen. The Hall’s Gullies site is more in jeopardy, as it remains a designated cutblock (area allowed to be forested) under the current Forest Management Operating Plan. It has been noted that populations of this lichen can decline even in protected areas, which has been linked to air pollution [9] and introduced herbivores, such as moose. [21]

The Atlantic population of the E. pedicellatum is protected in Canada under the Federal Species at Risk Act (SARA), and is the focus of an ongoing recovery strategy. [27] Efforts are being made, through land purchases and agreements with landowners, to formally protect areas of forest that are home to this rare species. [27] [28] Furthermore, conservationists are engaging with private and government forest managers to encourage their participation in the mapping of E. pedicellatum habitat and the implementation of management plans that will prevent further habitat loss. [27]

For the Alaskan population, in the United States, E. pedicellatum appears not to be listed on the United States Fish and Wildlife Service's Threatened and Endangered Species List. [29] However, the population is in the Denali National Park and Preserve, a protected area, and efforts have been made by researchers to not give away its location within the site so that they will not be tampered with. [24]

Threats and efforts

The biggest threat to E. pedicellatum is deforestation and habitat loss. [1] Through statistical modeling, it has been shown that E. pedicellatum has an increased chance of death when growing next to areas with deforestation. [30] The habitat of E. pedicellatum was shown to be cut down faster than it can grow back, which is of concern given E. pedicellatum's narrow habitat niche. [31] Current models predict that the Atlantic E. pedicellatum population will continue to decrease substantially over the next 25 years. [25]

Most current efforts in studying the status and conservation efforts of E. pedicellatum are through statistical modeling to predict its population and habitat quality. Through statistical modeling, more information has been developed on the habitat of E. pedicellatum, including how it prefers older, established forests with poor soil drainage. [32] However, statistical modeling has disadvantages, including making broad assumptions based on missing knowledge in lichen ecology. [33]

Efforts have been made to further understanding the effects of air quality. [34] Air quality is shown to have a major impact on E. pedicellatum, most likely due to it being a cyanolichen. [34] In particular, acid rain is a major concern to E. pedicellatum because its habitat is already acidic. [35] Research has also been conducted looking at impacts from invasive gastropods, which were shown to possibly be grazing on E. pedicellatum in Nova Scotia. More research is needed on their impacts. [36]

Researchers are trying to understand the genetic differences between each segmented population of E. pedicellatum. Currently, initial genetic analysis hypothesizes that the Pacific populations of E. pedicellatum are more diverse than the Atlantic population. However, research is still needed on how the populations interact with one another, specifically through gene flow. [15]

In Norway, the responses of transplanted thalli of Erioderma pedicellatum have been studied to assess the feasibility of increasing its distribution; the conclusion was that reintroduction of E. pedicellatum into the boreal rainforest is possible, but challenging, since well-lit branches of Picea abies with high base cation availability in humid canopy layers are rare. [6]

Related Research Articles

<span class="mw-page-title-main">Northern hawk-owl</span> Species of owl

The northern hawk-owl or northern hawk owl is a medium-sized true owl of the northern latitudes. It is non-migratory and usually stays within its breeding range, though it sometimes irrupts southward. It is one of the few owls that is neither nocturnal nor crepuscular, being active only during the day. This is the only living species in the genus Surnia of the family Strigidae, the "typical" owls. The species is sometimes called simply the hawk owl; however, many species of owls in the genus Ninox are also called "hawk owls".

<span class="mw-page-title-main">Northern flying squirrel</span> Species of rodent

The northern flying squirrel is one of three species of the genus Glaucomys, the only flying squirrels found in North America. They are found in coniferous and mixed coniferous forests across much of Canada, from Alaska to Nova Scotia, and south to the mountains of North Carolina and west to Utah in the United States. They are light brown with pale underparts and grow to a length of 25 to 37 cm. They are proficient gliders but uncoordinated walkers on the ground. They feed on a variety of plant material as well as tree sap, fungi, insects, carrion, bird eggs and nestlings. They mostly breed once a year in a cavity lined with lichen or other soft material. Except when they have young, they change nests frequently, and in winter a number of individuals may huddle together in a shared nest. Unlike most members of their family, flying squirrels are strictly nocturnal.

<span class="mw-page-title-main">Olive-sided flycatcher</span> Species of bird

The olive-sided flycatcher is a small to medium sized passerine bird in the family Tyrannidae, the Tyrant flycatcher family. It is a migratory species that travels from South to North America to breed during the summer. It is a very agile flyer and mainly consumes flying insects on flight. Since 2016, this species has been assessed as being near-threatened globally (IUCN) and threatened in Canada (SRA) due to its declining populations.

<i>Frullania polysticta</i> Species of liverwort

Frullania polysticta is a species of liverwort in the family Frullaniaceae. It is found only in Madeira and the Canary Islands and is considered a vulnerable species.

<span class="mw-page-title-main">Steve Selva</span>

Steven B. Selva is Professor Emeritus of Biology and Environmental Studies at the University of Maine at Fort Kent, a lichenologist, and curator of UMFK's lichen herbarium. Selva is an expert on stubble lichens, called so because their millimeter-high stalks resemble beard stubble.

<i>Parmeliella</i> Genus of lichen

Parmeliella is a genus of lichenized fungi in the family Pannariaceae. It occurs mainly in the tropics and sub-tropics, with species found in Africa, Asia, Australasia and South America. A recent (2020) estimate places 41 species in the genus.

<i>Pannaria</i> Genus of lichens in the family Pannariaceae

Pannaria is a genus of lichen-forming fungi in the family Pannariaceae. The widespread genus contains an estimated 51 species, found primarily in tropical regions.

<i>Erioderma</i> Genus of lichens

Erioderma is a genus of lichen-forming fungi in the family Pannariaceae. They are commonly called mouse ears or felt lichens, and are small, pale brown to olive-brown foliose cyanolichens with a fuzzy upper surface that have the cyanobacteria Scytonema as their photobiont. Most species are found in the tropics of Central and South America, although three species are found in coastal regions of North America where they generally grow on mossy branches in humid sites. All North American species are rare. Species of Erioderma can resemble Pannaria, Leioderma, or small Peltigera, but their fuzzy upper surface and lack of veins on their lower surface distinguishes them from these lichens.

<i>Frullania asagrayana</i> Species of liverwort

Frullania asagrayana is a reddish-brown species of liverwort in the family Frullaniaceae that grows in eastern North America.

<span class="mw-page-title-main">Boreal woodland caribou</span> Subspecies of caribou or reindeer in North America

The boreal woodland caribou, also known as Eastern woodland caribou, boreal forest caribou and forest-dwelling caribou, is a North American subspecies of reindeer found primarily in Canada with small populations in the United States. Unlike the Porcupine caribou and barren-ground caribou, boreal woodland caribou are primarily sedentary.

Caribou herds in Canada are discrete populations of seven subspecies that are represented in Canada. Caribou can be found from the High Arctic region south to the boreal forest and Rocky Mountains and from the east to the west coasts.

<i>Degelia plumbea</i> Species of lichen

Degelia plumbea is a species of grey to blue-black or brown foliose lichen in the genus Degelia. It mostly grows on trees in undisturbed woodlands but occasionally on coastal rocks. It is found widely in Britain and western Ireland as well as in America and Canada, as it grows in maritime Atlantic climates.

<i>Vahliella</i> Genus of lichens

Vahliella is a genus of nine species of lichen-forming fungi in the order Peltigerales. It is the only member of Vahliellaceae, a family circumscribed in 2010 to contain this genus. Vahliella was formerly placed in the family Pannariaceae until molecular phylogenetics showed that it did not belong there. Vahliella species are found in the Northern Hemisphere – mainly in North America, but also in Europe and India.

<i>Parmelia fraudans</i> Species of lichen

Parmelia fraudans is a species of foliose lichen in the family Parmeliaceae. It is found in Europe and North America, where it grows on rocks.

<i>Lepidocollema marianum</i> Species of lichen

Lepidocollema marianum is a species of cyanolichen in the family Pannariaceae. It was first scientifically described by Elias Fries in 1825 as Parmelia mariana. Per Magnus Jørgensen transferred it to the genus Lepidocollema in 2014 following a molecular phylogenetics-guided revision of the Pannariaceae.

<i>Fuscopannaria leucosticta</i> Species of lichen

Fuscopannaria leucosticta, commonly known as the rimmed shingle lichen, is a species of lichen in the family Pannariaceae. It has a squamulose (scaley) thallus that lacks soredia and isidia, but has abundant apothecia with distinct white rims. Although its main centres of distribution are eastern North America and southeast Asia, where it grows in damp forests, it has been reported from various other high-altitude, humid locations.

<i>Pseudocyphellaria perpetua</i> Species of lichen

Pseudocyphellaria perpetua is a species of corticolous (bark-dwelling), foliose (leafy) cyanolichen in the family Peltigeraceae. It was described as new to science in 2002 by lichenologists Bruce McCune and Jolanta Miądlikowska. It is distinguished from similar species, including some forms of P. crocata, by its yellow medulla and mostly marginal soralia. Other characteristics include its narrow, linear lobes, and its pale lower undersurface. Some molecular phylogenetic analysis suggests that Pseudocyphellaria perpetua and P. crocata are morphotypes of the same phylogenetic species. P. perpetua occurs on both conifer and hardwood trees in oceanic areas of the western North America and in the Russian Far East. It has also been documented as an uncommon species in Nova Scotia.

Leioderma cherokeense is a species of corticolous (bark-dwelling), foliose lichen in the family Pannariaceae.

Joergensenia is a fungal genus in the family Pannariaceae. It comprises a single species, Joergensenia cephalodina, which is a corticolous (bark-dwelling), squamulose lichen found in southern South America.

References

This article incorporates text from the ARKive fact-file "Boreal felt lichen" under the Creative Commons Attribution-ShareAlike 3.0 Unported License and the GFDL .

  1. 1 2 3 Scheidegger, C.; et al. (Lichen Specialist Group) (2003). "Erioderma pedicellatum". IUCN Red List of Threatened Species . 2003: e.T43995A10839336. doi: 10.2305/IUCN.UK.2003.RLTS.T43995A10839336.en . Retrieved 20 November 2021.
  2. Hue, A.-M. (1911). "Monographiam generis Solorinae Ach. Morphologice et anatomice, addito de genere Psoromaria Ayl. appendice". Mémoires de la Société nationale des sciences naturelles et mathématiques de Cherbourg. 4 (in Latin). 38 (8): 54.
  3. Lumbsch TH, Huhndorf SM (December 2007). "Outline of Ascomycota 2007". Myconet. 13. Chicago, USA: The Field Museum, Department of Botany: 1–58. Archived from the original on 2009-03-18.
  4. 1 2 Nelson, P, J Walton and C Roland. 2009. Erioderma pedicellatum (Hue) P.M.Jorg, new to the United States and western North America, discovered in Denali National Park and Preserve and Denali State Park, Alaska. Evansia 26: 19 – 23.
  5. "Boreal Felt Lichen Conservation Case Study | The Mohamed bin Zayed Species Conservation Fund". www.speciesconservation.org. Retrieved 2019-12-10.
  6. 1 2 3 4 Bolkan, V. Y.; Solhaug, K. A.; Gauslaa, Y (2024). "Growth and acclimation dynamics in reintroduced Erioderma pedicellatum (Hue) P.M.Jørg., a critically endangered cyanolichen in boreal rainforest". Flora. 320, 152624.
  7. 1 2 Sharnoff S, Brodo IM, Sharnoff SD (2001). Lichens of North America. New Haven, Connecticut: Yale University Press. ISBN   0-300-08249-5.
  8. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 COSEWIC Status Report for Erioderma pedicellatum
  9. 1 2 Jørgensen, Per M. 2000. Survey of the Lichen Family Pannariaceae on the American Continent, North of Mexico. The Bryologist: 103(4): 670-704.
  10. 1 2 Jørgensen, M. 2001. The present status of the names applicable to species and infraspecific taxa of Erioderma(lichenised Ascomycetes) included in Zahlbruckner's "Catalogus". Taxon 50(2): 525-541.
  11. 1 2 Jørgensen PM (1972). "Erioderma pedicellatum new combination equals Erioderma boreale in New Brunswick Canada". Bryologist. 75 (3): 369–71. doi:10.2307/3241481. JSTOR   3241481.
  12. Thompson ID, DJ Larson, and WA Montevecchi. 2003. Characterization of old “wet boreal” forests, with an example from balsam fir forests of western Newfoundland. Environmental Reviews 11: S23-S46.
  13. Goudie, Ri; Scheidegger, C; Hanel, C; Munier, A; Conway, E (2011-03-09). "New population models help explain declines in the globally rare boreal felt lichen Erioderma pedicellatum in Newfoundland". Endangered Species Research. 13 (3): 181–189. doi: 10.3354/esr00326 . ISSN   1863-5407.
  14. 1 2 Scheidegger, Christoph; Werth, Silke (August 2009). "Conservation strategies for lichens: insights from population biology". Fungal Biology Reviews. 23 (3): 55–66. Bibcode:2009FunBR..23...55S. doi:10.1016/j.fbr.2009.10.003.
  15. 1 2 3 4 Cornejo, C., P.R. Nelson, I. Stepanchikova, D. Himelbrant, P.-M. Jorgensen and C. Scheidigger. 2016. Contrasting pattern of photobiont diversity in the Atlantic and Pacific populations of Erioderma pedicellatum (Pannariaceae). The Lichenologist 48(4): 275 – 291
  16. Ahlner, S (1948). "Utbredningstyper bland Nordiska barrträdslavar". Acta Phytogeographica Suecica. 22: 1–257.
  17. Ahlner, S (1954). Värmlands märkligaste lav. In: Magnusson, N.H. (ed.), Natur i Värmland[Värmland's strangest lichen. In: Magnusson, N.H. (ed.), Nature in Värmland.] (in Swedish). Stockholm: Bokförlaget Svensk Natur. pp. 99–102.
  18. "NCC: Boreal felt lichen". www.natureconservancy.ca. Retrieved 2019-12-10.
  19. Nilsson, A.R.; Solhaug, K.A.; Gauslaa, Y (2022). "The globally threatened epiphytic cyanolichen Erioderma pedicellatum depends on a rare combination of habitat factors". Lichenologist. 54: 123–136.
  20. Reiso, S; Hofton, T.H. (2006). "Trønderlav Erioderma pedicellatum og fossefiltlav Fuscopannaria confusa funnet i Hedmark". Blyttia. 64: 83–88.
  21. 1 2 Cameron, R, C Hanel, I Goudie, and N. Neily. 2009. Boreal felt lichen; Current status, conservation issues and future prospects. Botanical Electronic News, no. 420.
  22. Newfoundland Lichen Education and Research Group Archived 2007-06-21 at the Wayback Machine
  23. Anderson, Frances; Bouchard, Mathieu; Boudreault, Catherine; McCarthy, John; Hanel, Claudia (2022). "Noteworthy range extensions of two lichens in Eastern Canada: Erioderma pedicellatum (Pannariaceae) new to Québec and Parmelia fraudans (Parmeliaceae) new to Nova Scotia". Evansia. 39 (1): 20–28. doi:10.1639/0747-9859-39.1.20.
  24. 1 2 Stehn, Sarah E.; Nelson, Peter R.; Roland, Carl A.; Jones, Jennifer R. (2013-04-17). "Patterns in the occupancy and abundance of the globally rare lichen Erioderma pedicellatum in Denali National Park and Preserve, Alaska". The Bryologist. 116 (1): 2. doi:10.1639/0007-2745-116.1.002. ISSN   0007-2745. S2CID   86253216.
  25. 1 2 Cameron, Robert P.; Toms, Brad (2016-06-21). "Population decline of endangered lichen Erioderma pedicellatum in Nova Scotia, Canada". Botany. 94 (7): 565–571. doi: 10.1139/cjb-2016-0052 . hdl: 1807/72889 . ISSN   1916-2790.
  26. "The IUCN Red List of Threatened Species". IUCN Red List of Threatened Species. Retrieved 2019-12-10.
  27. 1 2 3 "Species at Risk Public Registry". May 2009. Archived from the original on 10 June 2013. Retrieved 26 July 2011.
  28. "The Nature Conservancy of Canada". May 2009. Archived from the original on 27 September 2011. Retrieved 26 July 2011.
  29. "ECOS Environmental Conservation Online System". U.S. Fish and Wildlife Services. Retrieved 10 December 2019.
  30. Cameron, Robert P.; Neily, Tom; Clapp, Harold (May 2013). "Forest harvesting impacts on mortality of an endangered lichen at the landscape and stand scales". Canadian Journal of Forest Research. 43 (5): 507–511. doi:10.1139/cjfr-2012-0452. ISSN   0045-5067.
  31. Cameron, Robert; Goudie, Ian; Richardson, David (November 2013). "Habitat loss exceeds habitat regeneration for an IUCN flagship lichen epiphyte: Erioderma pedicellatum". Canadian Journal of Forest Research. 43 (11): 1075–1080. doi:10.1139/cjfr-2013-0024. ISSN   0045-5067.
  32. Power, T.D.; Cameron, R.P.; Neily, T.; Toms, B. (July 2018). "Forest structure and site conditions of boreal felt lichen ( Erioderma pedicellatum ) habitat in Cape Breton, Nova Scotia, Canada". Botany. 96 (7): 449–459. doi:10.1139/cjb-2017-0209. ISSN   1916-2790. S2CID   89888719.
  33. Ellis, Christopher (2019-04-04). "Climate Change, Bioclimatic Models and the Risk to Lichen Diversity". Diversity. 11 (4): 54. doi: 10.3390/d11040054 . ISSN   1424-2818.
  34. 1 2 Cameron, Robert P.; Neily, Thomas; Richardson, David H. S. (March 2007). "Macrolichen Indicators of Air Quality for Nova Scotia". Northeastern Naturalist. 14 (1): 1–14. doi:10.1656/1092-6194(2007)14[1:MIOAQF]2.0.CO;2. ISSN   1092-6194. S2CID   85729275.
  35. Cameron, Robert (2004). "A Second Location for the Rare Boreal Felt Lichen in Nova Scotia". Evansia. 21: 40–41. doi: 10.5962/p.346587 . S2CID   254352740 via Research Gate.
  36. Cameron, Robert (2009). "Are Non-Native Gastropods a Threat to Endangered Lichens?". The Canadian Field-Naturalist. 123 (2): 169–171. doi: 10.22621/cfn.v123i2.697 . ISSN   0008-3550.