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Bryoria salazinica Brodo & D. Hawksw.

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Scientific name
Bryoria salazinica
Brodo & D. Hawksw.
Common names
Smooth horsehair lichen
IUCN Specialist Group
Assessment status
Assessment date
IUCN Red List Category
IUCN Red List Criteria
C2a(i); D
Paquette, H., Lendemer, J. & Yahr, R.
McMullin, T.

Assessment Notes

The content on this page is fetched from The IUCN Red List of Threatened Species: https://www.iucnredlist.org/species/194660286/194678109


Bryoria salazinica is endemic to north-eastern North America. In total, there is a maximum of 17-29 mature individuals, known from seven locations. There is a continuing population decline, with past declines inferred to have been caused by habitat loss and air pollution. The population is thought to be continuing to decline due to impacts from logging, climate change, and development. Therefore, this species is Critically Endangered; C2a(i); D.

Geographic range

Bryoria salazinica is endemic to eastern North America. It is known from the Canadian provinces of New Brunswick, Newfoundland and Labrador, Nova Scotia, Prince Edward Island and Quebec (Brodo and Hawksworth 1977, Laflamme-Levesque et al. 1979, Gowan and Brodo 1988, Paquette and McMullin 2020). It was historically known in the United States (US) from Maine and Massachusetts (Brodo and Hawksworth 1977). Modern occurrences (post-1960) are exclusive to maritime Canada. Despite extensive study of macrolichens in north-eastern US, this lichen has not been found in the region since 1909, where it was known from only three records. The lack of new records from this highly studied region suggests that it has been extirpated from this part of its range.

Population and Trends

The extant global population appears to be locally rare and restricted to north-eastern North America, specifically hyper-coastal environments. A total of only 17 occurrences are known, and all contemporary records for this species are in Canada (12 occurrences from seven localities, only one reported in the last 40 years), with an estimated maximum number of 17-29 extant mature individuals. Although it has historically been reported from the US, these sites are presumed extirpated, and no new occurrences have been reported from the US since 1909, despite extensive study and collection activity in north-eastern, and specifically coastal US (e.g. Hinds and Hinds 2007, Seaward et al. 2017). Sites in the US were likely extirpated after 1930 due to increased development and industrialization at that time. For example, the record from Massachusetts (1878) is presumed extirpated due to development of the city of Springfield throughout the early 1900's.

This species has been found only once in the last decade (in the province of Quebec; Paquette and McMullin 2020), despite large-scale activity throughout the Canadian Maritimes by expert lichenologists (e.g. Selva 1999, Anderson 2014, McMullin et al. 2012, 2017b, McCarthy et al. 2015, McMullin and Wiersma 2017, McMullin and Arsenault 2019, Tumur and Richardson 2019); and the US (as noted). The exact number of mature individuals at each site is unknown; however, given overall rarity and that it is represented by a single voucher from all but one site (the three collections from Prince Edward Island National Park in Prince Edward Island, Canada are represented by a single occurrence point), we estimate that the modern sites host five or fewer functional individuals. We infer a population reduction, given the likelihood of the US subpopulations being extirpated within the last 90 years and the continued infrequent detection of this species in Canada.

Population Trend: decreasing

Habitat and Ecology

This species is an epiphtye on coniferous trees (primarily balsam fir) (Brodo and Hawksworth 1977, Hinds and Hinds 2007). It is restricted to exposed coastal environments away from urban development. Exceptionally, it has been reported from Acer rubrum and not immediately coastal, but in proximity to maritime influences from the Bay of Fundy in New Brunswick, Canada (Gowan and Brodo 1988). It is a greenish-brown pendant fruticose lichen with a smooth cortex, lacks isidia or soredia, and its branches are characteristically curled and twisted (Brodo and Hawksworth 1977, Paquette and McMullin 2020). Chemically, it is distinguished from other Bryoria species by the presence of salazinic acid in its cortex (Brodo and Hawksworth 1977).


In addition to loss of habitat due to development and/or logging, climate change related impacts, such as changes to humidity regimes (including rain, dew and fog), increasing severity of storms and sea-level rise are the most severe threats to this species. Although Bryoria salazinica has not been studied in detail, studies of other Bryoria species have identified climate-related threats. For example, Gauslaa (2014) outlined the importance of humidity, dew and rainfall as drivers of distribution in hair lichens, including Bryoria species. Additionally, a Swedish study by Esseen et al. (2016) showed Bryoria occurrence to decrease with warming temperature (warming temperatures have already been observed in Canada and are predicted to continue; ECCC 2019) and predicted large distribution shifts as a result of climate change, nitrogen deposition and forest structure in the hair lichens they studied. Phinney et al. (2021) found additional support for climate change driven distributional shifts in hair lichens (including Bryoria) and showed that Bryoria species are likely to decrease as a result of warmer, wetter winters and thicker forest canopies, which aligns with predictions for the Canadian Maritimes (ECCC 2017). On the west coast of North America, Glavich et al. (2005) also found evidence of temperature negatively effecting occurrence of two rare Bryoria species with hyper-coastal distributions. In addition to these atmospheric climate change threats, the physical threat of diminishing habitat from sea-level rise and severe storms destroying host trees is expected as extreme weather events are predicted to increase under most scenarios, corresponding with increased warming (ECCC 2017)

Declining air quality is an additional suspected threat; however, more research is needed to understand the extent of this threat. Pollution responses in lichens are complex (e.g. Ellis et al. 2014, 2015), due to the varying compounds and their effects as directly toxic or as modifiers of their environments, but several Bryoria species are known to be sensitive to nitrogen (as NHx) deposition and present only where air quality is high and fertility (i.e., nutrient deposition) is low (e.g. Geiser and Neitlich 2007). The balance of nitrogen deposition has strongly shifted towards NHx over the past decades, a trend that has overwhelmingly grown across the area of distribution of this species (Zhang et al. 2018), suggesting a potential risk. Finally, no economic use or trade is presently known for this species; however, collection due to its rarity does pose a threat.

Conservation Actions

Four of the Canadian locations of Bryoria salazinica (one each in New Brunswick, Newfoundland & Labrador, Quebec, and Prince Edward Island) are found in National Parks which are legally protected through the National Parks Act in Canada. This species it not otherwise legally protected in Canada or the US. Protection of the known sites and habitats is recommended for the preservation of this rare species. Education for local land managers and owners should be provided to raise awareness of its status and sensitive habitat needs.

The Canadian occurrences reported prior to 2017 should be examined to verify that they are extant as is presumed here. Analyses of habitat availability in north-eastern North America that a) identify the amount of available habitat and b) predict potential shift and/or loss of its habitat under different climate change scenarios would be valuable contributions for managing this species. Additionally, the impact of air quality on B. salazinica should be studied to clarify the extent of this threat.

Use and Trade

Presently, no economic use or trade is known for this species; however, collection due to its rarity does pose a threat. Pressures from collection should be mitigated in research conducted on this lichen.

Source and Citation

Paquette, H., Lendemer, J. & Yahr, R. 2021. Bryoria salazinica. The IUCN Red List of Threatened Species 2021: e.T194660286A194678109. https://dx.doi.org/10.2305/IUCN.UK.2021-2.RLTS.T194660286A194678109.en .Accessed on 27 September 2022

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