Circular-leaved Peat Moss (Sphagnum cyclophyllum): COSEWIC assessment and status report 2024

Official title: COSEWIC Assessment and Status Report on the Circular-leaved Peat Moss (Sphagnum cyclophyllum) in Canada

Endangered

2024

COSEWIC assessment summary

Assessment summary – November 2024

Common name: Circular-leaved Peat Moss

Scientific name: Sphagnum cyclophyllum

Status: Endangered

Reason for designation: This medium-sized peat moss is known in Canada only from three sites within 10 km from each other in a single watershed of southwestern Nova Scotia; these sites are 700 km from the nearest ones in the United States. Dispersal ability of the species is poor because sexual reproduction is rare and asexual reproduction by fragmentation has never been observed. Fewer than 250 individuals have so far been found in Canada. The species grows in shallow depressions in three open peatlands, each of which supports few individuals. The most important threats include climate change-induced drought and increased fire frequency. The unexpected recent fire that affected one site highlights the importance of the latter threat.

Occurrence: Nova Scotia

Status history: Designated Endangered in November 2024.

COSEWIC executive summary

Circular-leaved Peat Moss

Sphagnum cyclophyllum

Wildlife species description and significance

Sphagnum cyclophyllum Sullivant, Circular-leaved Peat Moss, is significant for its rarity in Canada, where the species is at the extreme northern edge of its geographical range and known from only three close occurrences. The species’ impressive ability to retain water greatly influences hydrology. It also plays an important role in carbon cycling and in the chemistry and microbiology of its habitat.

Aboriginal (Indigenous) knowledge

All species are significant and are interconnected and interrelated. There is no species-specific Aboriginal traditional knowledge (ATK)in the report.

Distribution

Circular-leaved Peat Moss is virtually endemic to the Americas with only one record (which is questionable) reported outside the Americas, in Russia. Apart from the Russian occurrence, the species has a disjunct range with populations found in North America mostly along the east coast and the Gulf of Mexico, and in South America, in Columbia and Brazil. There are some inland disjunct subpopulations in Tennessee and in the northern parts of Alabama and New York State.

In Canada, Circular-leaved Peat Moss is only known from a single population in Nova Scotia. Although herbarium specimens and observations come from almost the entire Atlantic coast of the United States, these occurrences are sporadic, and the species is considered rare in many U.S. states.

Habitat

Across its distribution, Circular-leaved Peat Moss prefers open grassy savannahs, pine barrens and other pinelands, as well as the edges of ditches along sandy roads that are submerged for part of the year. It also occurs in depressions in open to semi-open peatlands that dry up in summer. In Canada, it has been collected in dried depressions of open bog habitat and in submerged ditches.

In the main part of its range, this Sphagnum seems to be dependent on small-scale substrate disturbances and is found on recently exposed soil and in vegetation types subject to fire such as grassy savannahs and pinelands.

Biology

Sphagnum, also known as peat moss, is a group of mosses that commonly inhabit wet areas, and are considered the “engineers” of bogs and fens. They are perennial species with indeterminate apical growth and live tightly appressed together in low hummocks or mats.

Circular-leaved Peat Moss is dioicous, meaning male and female reproductive structures are found on separate plants. The capsules are immersed in the leaves and therefore less effective for dispersal. Sexual reproduction is rare, and few fertile individuals have been observed throughout the species’ range. Vegetative fragmentation appears to be its main mode of reproduction.

Dispersal of vegetative fragments in Circular-leaved Peat Moss is presumed to be mainly passive, occurring by wind or water. It is possible that the species could also be dispersed by animals; however, there is no mention of this in the literature.

Population sizes and trends

There is no information on population trends in Circular-leaved Peat Moss in North America. The Canadian population consists of three occurrences, which are located in Shelburne County, Nova Scotia and cover an area ranging from 0.2 to 124 m² depending on the site. At each occurrence, colonies are found in one or more depressions, where the species’ cover ranges from abundant (85% cover) to only a few stems in the depression. Circular-leaved Peat Moss typically grows in small patches that do not extend beyond the depression in which they are found.

Threats and limiting factors

Climate change is the most important threat to Circular-leaved Peat Moss, since regional drought can decrease the abundance of peatlands and since large, high intensity fires could destroy all of the known colonies in Canada given their clustered distribution.

Recreational activities may pose a threat to and may destroy Circular-leaved Peat Moss colonies at the most impacted sites. Intensive ATV use has been recorded at two of the three known sites in Canada.

Limiting factors include the species’ narrow habitat tolerance and environmental tolerance, its very limited sexual reproduction, and its poor dispersal ability.

Protection, status and ranks

Circular-leaved Peat Moss is not protected internationally nor is it protected in most U.S. states where it occurs. Globally it is ranked Vulnerable (G3). Among the 12 states where it is found in the United States, it is considered to be Vulnerable in New Jersey (S3), Georgia (S3), and Mississippi (S3), and apparently secure in Virginia (S4?). In Canada and in the province of Nova Scotia, where the only known population is found, it is designated Critically Imperiled (N1?S1?).

Technical summary

Scientific name: Sphagnum cyclophyllum

English common name: Circular-leaved Peat Moss

French common name: Sphaigne à feuilles rondes

Range of occurrence in Canada (province/territory/ocean): Nova Scotia

Demographic information

Generation time (usually average age of parents in the population; indicate if another method of estimating generation time indicated in the IUCN guidelines (2011) is being used)

11 to 25 yrs

Estimation method: (Bergamini et al. 2019)

Long-lived species

Is there an [observed, inferred or projected] continuing decline in number of mature individuals?

Inferred due to loss of historical sites and larger proportion of moribund colonies

Estimated percent of continuing decline in total number of mature individuals within [5 years or 2 generations, whichever is longer up to a maximum of 100 years]

Unknown

[Observed, estimated, inferred, or suspected] percent [reduction or increase] in total number of mature individuals over the last [10 years, or 3 generations, whichever is longer up to a maximum of 100 years].

Unknown

[Projected or suspected] percent [reduction or increase] in total number of mature individuals over the next [10 years, or 3 generations, whichever is longer up to a maximum of 100 years].

>78% reduction suspected over the next 3 generations because of the predominance of small, moribund colonies (individuals).

[Observed, estimated, inferred, or suspected] percent [reduction or increase] in total number of mature individuals over any period [10 years, or 3 generations, whichever is longer up to a maximum of 100 years], including both the past and the future.

Suspected reduction of 1-80% in the future because of the predominance of small, moribund colonies (individuals). Also see threat calculator

Are the causes of the decline a. clearly reversible and b. understood and c. ceased?

Yes, for most occurrences where the decline results from human disturbance (2/3)

1. Yes, for most occurrences where the decline results from human disturbance (2/3)
2. Yes. Prolonged drought due to climate change.
3. No

Are there extreme fluctuations in number of mature individuals?

No

Extent and occupancy information

Estimated extent of occurrence (EOO)
EOO = 12 km² (based on IAO value; EOO cannot be less than IAO value)

12 km²

Index of area of occupancy (IAO)
(Always report 2x2 grid value).

12 km²

Is the population “severely fragmented” that is, is > 50% of its total area of occupancy in habitat patches that are (a) smaller than would be required to support a viable population, and (b) separated from other habitat patches by a distance larger than the species can be expected to disperse?

1. No
2. Yes

Number of “locations” (use plausible range to reflect uncertainty if appropriate)

1 to 3 locations based on the three different threats (climate change, recreational activities, and mining/quarrying) which operate independently in each occurrence.

Is there an [observed, inferred, or projected] decline in extent of occurrence?

Yes, inferred, due to threat of climate change (drought, wildfire).

Is there an [observed, inferred, or projected] decline in index of area of occupancy?

Yes, inferred, due to threat of climate change (drought, wildfire).

Is there an [observed, inferred, or projected] decline in number of subpopulations?

Yes, inferred, due to threat of climate change (drought, wildfire)..

Is there an [observed, inferred, or projected] decline in number of “locations”?

Yes, inferred, due to threat of climate change (drought, wildfire).

Is there an [observed, inferred, or projected] decline in [area, extent and/or quality] of habitat?

Yes, inferred decline in area, extent and/or quality of habitat due to threat of climate change (drought, wildfire).

Are there extreme fluctuations in number of subpopulations?

No

Are there extreme fluctuations in number of “locations”?

No

Are there extreme fluctuations in extent of occurrence?

No

Are there extreme fluctuations in index of area of occupancy?

No

Number of mature individuals (in each subpopulation)

Bloody Creek

12 to 166

Quinns Meadow Conservation Lands (CL)

1

Pug Lake

1

Total

14 to 168

Quantitative analysis

Is the probability of extinction in the wild at least [20% within 20 years or 5 generations whichever is longer up to a maximum of 100 years, or 10% within 100 years]?

No analysis performed.

Threats

Was a threats calculator completed for this species?

Yes, December 13, 2022 (see Appendix 1)

The main threats, in order of importance, are:

11.2 Climate change and severe weather: increase in drought events resulting in habitat losses through a reduction in peaty areas and the drying up of depressions, and/or more frequent and severe fires, temperature extremes, and storms and flooding resulting in habitat gains. (Very high-Medium impact)

7.1 Fire and Fire Suppression: Fire could detrimentally affect the species at sites that are severely burned. However, fire may also be beneficial as it could open up new habitat for colonization for the species (High-Low impact)

6.1 Recreational activities: Habitat destruction by motorized vehicles (High-Low impact)

1.1 Housing and urban areas: possibility of backfilling for construction (Low impact)

Overall assessment was Very high - High

What limiting factors are relevant?

species’ narrow habitat tolerance
limited environmental tolerance (sensitivity to drought)
very limited sexual reproduction
poor dispersal ability

Rescue effect (immigration from outside Canada)

Status of outside population(s) most likely to provide immigrants to Canada

Unknown

Is immigration known or possible?

No (closest population is in Massachusetts, approx. 700 km away in a straight line)

Would immigrants be adapted to survive in Canada?

Unknown

Is there sufficient habitat for immigrants in Canada?

Unknown

Are conditions deteriorating in Canada?

Yes, due to climate change, and if industrial development, recreational activities and residential development are not prohibited in peatlands

Are conditions for the source (that is, outside) population deteriorating?

Yes, assumed because the status of the species is “Vulnerable” in USA)

Is the Canadian population considered to be a sink?

No (the closest population located in Massachusetts is too far away for the exchange of spores or fragments to occur)

Is rescue from outside populations likely?

No

Status history

COSEWIC status history: designated endangered in November 2024

Status and reasons for designation

Status: Endangered

Alpha-numeric codes: B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v); C2a(i); D1

Reason for designation: This medium-sized peat moss is known in Canada only from three sites within 10 km from each other in a single watershed of southwestern Nova Scotia; these sites are 700 km from the nearest ones in the United States. Dispersal ability of the species is poor because sexual reproduction is rare and asexual reproduction by fragmentation has never been observed. Fewer than 250 individuals have so far been found in Canada. The species grows in shallow depressions in three open peatlands, each of which supports few individuals. The most important threats include climate change-induced drought and increased fire frequency. The unexpected recent fire that affected one site highlights the importance of the latter threat.

Applicability of criteria

Criterion A (decline in total number of mature individuals):

Not applicable. May meet Endangered A3b. Future population reduction decline may exceed threshold for 50%.

Criterion B (small distribution range and decline or fluctuation):

Meets Endangered, B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v). EOO of 12 km² and IAO of 12 km² are below the threshold for Endangered, population occurs at <5 locations and the species is experiencing a continuing inferred decline in (i) EOO, (ii) IAO, (iii) extent or quality of habitat, (iv) number of locations or subpopulations, and (v) number of mature individuals.

Criterion C (small and declining number of mature individuals):

Meets Endangered, C2a(i). Number of mature individuals is 14-168, with fewer than 250 in any one subpopulation, and there is an inferred continuing decline.

Criterion D (Very small or restricted population):

Meets Endangered, D1. Number of mature individuals estimated to be 14-168.

Criterion E (quantitative analysis):

Not applicable. Analysis not conducted.

COSEWIC history

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) was created in 1977 as a result of a recommendation at the Federal-Provincial Wildlife Conference held in 1976. It arose from the need for a single, official, scientifically sound, national listing of wildlife species at risk. In 1978, COSEWIC designated its first species and produced its first list of Canadian species at risk. Species designated at meetings of the full committee are added to the list. On June 5, 2003, the Species at Risk Act (SARA) was proclaimed. SARA establishes COSEWIC as an advisory body ensuring that species will continue to be assessed under a rigorous and independent scientific process.

COSEWIC mandate

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assesses the national status of wild species, subspecies, varieties, or other designatable units that are considered to be at risk in Canada. Designations are made on native species for the following taxonomic groups: mammals, birds, reptiles, amphibians, fishes, arthropods, molluscs, vascular plants, mosses, and lichens.

COSEWIC membership

COSEWIC comprises members from each provincial and territorial government wildlife agency, four federal entities (Canadian Wildlife Service, Parks Canada Agency, Department of Fisheries and Oceans, and the Federal Biodiversity Information Partnership, chaired by the Canadian Museum of Nature), three non-government science members and the co-chairs of the species specialist subcommittees and the Aboriginal Traditional Knowledge subcommittee. The Committee meets to consider status reports on candidate species.

Definitions (2024)

Wildlife Species

A species, subspecies, variety, or geographically or genetically distinct population of animal, plant or other organism, other than a bacterium or virus, that is wild by nature and is either native to Canada or has extended its range into Canada without human intervention and has been present in Canada for at least 50 years.

Extinct (X)

A wildlife species that no longer exists.

Extirpated (XT)

A wildlife species no longer existing in the wild in Canada, but occurring elsewhere.

Endangered (E)

A wildlife species facing imminent extirpation or extinction.

Threatened (T)

A wildlife species likely to become endangered if limiting factors are not reversed.

Special Concern (SC)^*

A wildlife species that may become a threatened or an endangered species because of a combination of biological characteristics and identified threats.

Not at Risk (NAR)^**

A wildlife species that has been evaluated and found to be not at risk of extinction given the current circumstances.

Data Deficient (DD)^***

A category that applies when the available information is insufficient (a) to resolve a species’ eligibility for assessment or (b) to permit an assessment of the species’ risk of extinction.

^* Formerly described as “Vulnerable” from 1990 to 1999, or “Rare” prior to 1990.

^** Formerly described as “Not In Any Category”, or “No Designation Required.”

^*** Formerly described as “Indeterminate” from 1994 to 1999 or “ISIBD” (insufficient scientific information on which to base a designation) prior to 1994. Definition of the (DD) category revised in 2006.

The Canadian Wildlife Service, Environment and Climate Change Canada, provides full administrative and financial support to the COSEWIC Secretariat.

Wildlife species description and significance

Name and classification

Scientific name: Sphagnum cyclophyllum Sullivant, in A. Gray, Manual ed. 2. 611. 1856. (FNA 2007; Knapp and McAvoy 2012).

Related scientific name: Sphagnum cyclophyllum Sull. and Lesq. in Sull., in Gray (Harvey and Maass 1978).

Common name: Circular-leaved Peat Moss.

Kingdom: Plantae

Phylum: Bryophyta

Class: Sphagnopsida

Order: Sphagnales

Family: Sphagnaceae

Genus: Sphagnum

Section: Subsecunda

Morphological description

Circular-leaved Peat Moss forms dense colonies of erect or procumbent stems ranging in colour from yellowish green to brown or even reddish (Gray 1862; Flora of North America Editorial Committee 2007). Under dry conditions, the stems become yellowish to whitish and brittle.

The most distinctive features of Circular-leaved Peat Moss are the absence of a capitulum and the very small number of lateral branches. Its main stem, which is sturdy and woody in appearance, is brown to black, sparsely branched, and covered with broadly ovate, closely imbricate leaves. This stem, which is turgid, cylindrical and rope-/worm-like (that is, julaceous), ends in an endive-shaped bud cupped by terminal leaves. All the leaves are large, concave, cucullate and 2 to 3 mm long. Atypically for the genus, the species is isophyllous, meaning that the leaves on the main stem, lateral branches, and capitulum are all similar (Figure 1).

Figure 1. Photographs showing the morphological characteristics of Circular-leaved Peat Moss: A) general growth habit; B) stem leaves; C) cross-section of stem; D) hyalocysts and leaf pores. Photos: Maurane Bourgouin and Marion Barbé.

Designatable units

There is only one designatable unit of the species in Canada, specifically the Clyde River valley population in Shelburne County, Nova Scotia. It is composed of three occurrences: Bloody Creek, Pug Lake, and Quinns Meadow Conservation Lands situated in a 11.93 km² area. Given the close proximity of the occurrences, it is unlikely that there is any genetic or behavioural differentiation among them.

Special significance

This species is significant from a biogeographical perspective. The three occurrences are the only ones known in Canada, where the species is at the northern edge of its range in North America and disjunct from the nearest subpopulations, which are located about 700 km away.

The specific significance of Circular-leaved Peat Moss and its role in ecosystem functioning are unknown. However, Sphagnum species help to retain moisture and nutrients and play a role in the thermal regulation of soils. Sphagnum accumulation in peatlands as a result of slow decomposition (the process that gives rise to this type of ecosystem) also contributes to atmospheric carbon sequestration (Turetsky et al. 2012). In addition, Sphagnum species are used by animal species (for example, insects and small mammals) for shelter and perhaps as a food source (Glime 2007).

There are no reported anthropogenic uses of Circular-leaved Peat Moss specifically. Other Sphagnum species growing in Ireland and Canada are used as insulating and horticultural materials and as heating fuel. The species may be incidentally exploited at sites where it occurs among other Sphagnum species. The species’ rarity and its sporadic occurrence may explain its limited anthropogenic and socio-economic importance.

Aboriginal (Indigenous) knowledge

Aboriginal traditional knowledge (ATK) is relationship-based. It involves information on ecological relationships between humans and their environment, including characteristics of species, habitats, and sites. Laws and protocols for human relationships with the environment are passed on through teachings and stories, and Indigenous languages, and can be based on long-term observations. Place names provide information about harvesting areas, ecological processes, spiritual significance or the products of harvest. ATK can identify a species’ life-history characteristics or distinct differences between similar species.

Cultural significance to Indigenous peoples

There is no species-specific ATK in this report. However, Circular-leaved Peat Moss is important to Indigenous Peoples who recognize the interrelationships of all species within the ecosystem.

Distribution

Global range

Circular-leaved Peat Moss is native and endemic to the Americas (North and South America; Figure 2). Although there is one published report of the species from Russia (Kasymov and Agafontsev 2016), no specimens are known to be associated with it, and no response or confirmation has been forthcoming to date from the authors of this record. In North America, the species occurs all along the Gulf of Mexico and along the Atlantic coast from Texas to New Jersey, as well as farther north, in Massachusetts (United States) and Nova Scotia (Canada) (Figure 3). Most Circular-leaved Peat Moss occurrences in North America correspond to the extent of the Atlantic Coastal Plain Ecosystem, which is characterized by a rich flora of phylogenetically unrelated rare species (Series, 2016), and to the pine barrens that extend from Florida to Maine. Although there are some records from New York, Maine, Vermont, and New Hampshire, they date back 60 to 130 years, and the identifications have not been verified or confirmed (Shaw pers. comm. 2020). There are no records of the species in New Brunswick.

Figure 2. Map of the global distribution of Circular-leaved Peat Moss. The black dots indicate the countries or states where the species is present (adapted from Flora of North America Editorial Committee 2007; Bryophyte Portal 2020). Map created by Maurane Bourgouin and Marion Barbé using PowerPoint.

Figure 3. Map of the North American distribution of Circular-leaved Peat Moss. The red dots correspond to the occurrences compiled by COSEWIC based on herbarium data (UBC, Duke, and Atlantic Canada Conservation Data Centre herbaria; Bryophyte Portal 2020; Mid-Atlantic Herbaria Consortium 2020). Map created by Maurane Bourgouin and Marion Barbé with Esri ArcGIS.

Atlantic Coastal Plain vascular plant species are found in southwestern Nova Scotia, and along the coast of Georgian Bay in Ontario (Environment Canada and Parks Canada Agency 2015).

The species has a limited Canadian range and is isolated from populations in the United States, with the closest occurrences in Massachusetts, roughly 700 km away (in a straight line).

Circular-leaved Peat Moss has also been found in South America, in Colombia and Brazil (Bryophyte-Portal 2020).

Canadian range

In Canada, the species is limited to a single watershed in southwestern Nova Scotia. Despite intensive searching for Sphagnum, the Circular-leaved Peat Moss has not been found elsewhere in the Maritimes. To date, the only three occurrences of the species are located within 10 km of one another in Shelburne County, more specifically at the confluence of Bloody Creek and the Clyde River (Figure 4).

Figure 4. Map of the current and historical distribution of Circular-leaved Peat Moss in Canada. Middle Clyde River and Beaverdam Lake sites are approximate localities of the specimens collected by Maass and held in the NSPM herbarium. These sites were not visited during the 2021 field survey. Note that for NSPM specimen 10930, the Middle Clyde River is mentioned as the locality, but the description does not match this locality. UPC7 and UPC8 in Queen’s Meadow Natural Lands (QMNL) are approximate localities of historical records that were visited, but the species was not found. Map created by Maurane Bourgouin and Marion Barbé based on herbarium data (UBC, Duke and Wolfgang Maass [New Brunswick Museum] and Atlantic Canada Conservation Data Centre herbaria) and fieldwork in 2021.

Previous searches and those associated with this report failed to locate any sites outside of the Clyde River area. The genus Sphagnum is well documented in Atlantic Canada and has been collected at many sites throughout the region (Figure 5). Despite this immense collecting effort, Circular-leaved Peat Moss has not been found outside Shelburne County, Nova Scotia.

Figure 5. Map showing collecting sites in Atlantic Canada for the genus Sphagnum. Created by René Belland from data available on the Bryophyte-Portal (2024).

Extent of occurrence and area of occupancy

In Canada, the extent of occurrence (EOO) of Circular-leaved Peat Moss is 12 km² and its index of area of occupancy (IAO) is 12 km² based on a 2×2 km grid calculation. As per IUCN guidelines, the EOO has been adjusted to be equal to the IAO to ensure consistency with the definition of IAO as an area within EOO. The extent of occurrence and area of occupancy were estimated in Google Earth Pro, using field observations from September 2021, information found in digital herbarium records, and information obtained from experts.

The biological area of occupancy was estimated at 50.46 m², based on measurements made during the fieldwork.

Search effort

The Canadian range of Circular-leaved Peat Moss described in this report is partially based on the study of Clapp and Neily (2017), in which occurrences were located (or relocated) during a census of rare lichens and bryophytes. Those authors manually calculated, in situ, the area occupied by the species and collected specimens, which they subsequently identified and described in the laboratory (Neily 2020).

In addition, for the purpose of this report, botanical inventories were conducted in Nova Scotia in September 2021, following a review of herbarium data and a cartographic study of the species’ habitat preferences. To narrow down search effort to the most likely areas, a preliminary map of site preferences was made based on descriptions of habitat from herbarium specimens. Raster images of surficial deposits, forest composition and wetlands were used, and their values were ranked according to the species’ preference from one to five, where one indicates a low affinity for a given substrate/habitat, and five, a high affinity. Ranked raster images were then overlaid using the Raster Calculator tool in Esri’s ArcMap. In the resulting map (Figure 6), the sites with the highest scores had the highest probability of being present. Note that this map was only constructed for Shelburne and Yarmouth counties. The assessment of potential habitat was based on a simple calculation that did not consider the interaction between predictors and their contribution to the species’ presence. The map was constructed to support fieldwork; therefore, conclusions based on this map must be treated with caution. Further analyses are needed to refine habitat predictions for Circular-leaved Peat Moss. Nevertheless, the habitat prediction map shows a concentration of favourable sites in the Clyde River valley and in patchy areas in Shelburne County.

Figure 6. Map of potential Circular-leaved Peat Moss habitat based on surficial deposits and forest cover. Note: (1) the probability of occurrence of Circular-leaved Peat Moss in an area is enhanced in a fire zone; (2) only post-1986 fires are shown. Potential habitat assumes a link between fire and the presence of Circular-leaved Peat Moss; this link is not been well documented or supported in Canada. Map created by Maurane Bourgouin and Marion Barbé with Esri’s ArcGIS based on a literature review, herbarium data (UBC, Duke and Wolfgang Maass [New Brunswick Museum] and Atlantic Canada Conservation Data Centre herbaria) and fieldwork in 2021.

The fieldwork involved visits to a total of 25 sites (Table 1; Figure 7) in Shelburne and Yarmouth counties along the Clyde River and also in a neighbouring watershed (Woods Harbour) where similar habitat is also found (Figure 4). These visits involved a total search effort of 96 hours. The presence of Circular-leaved Peat Moss at three previously documented sites (Bloody Creek, Quinns Meadow Conservation Lands, and Pug Lake) was confirmed. The species was not detected at three other historical sites (QMNR, UPC7 and UPC8, Table 1, Figure 4). Information on the specific localities of these sites was so vague, it was impossible to confirm whether the species has been extirpated from these sites. Two other historical sites were not visited (Beaverdam and Middle Clyde, Table 1 and Figure 4). Note that the Middle Clyde River site is approximate. The locality mentioned and its description in the herbarium record from the Nova Scotia Provincial Museum do not match. Although a fire polygon is present near Middle Clyde River (an area not yet searched), searches for the species in the burned peatlands at four sites in the Woods Harbour watershed failed to locate it (Pubnico site, see Table 1).

A final field survey was conducted in June 2024 to check for the continued presence of Circular-leaved Peat Moss in the Quinns Meadow occurrence after the 2023 Shelburne fire.

Figure 7. Map of sites visited during the 2021 field survey for Circular-leaved Peat Moss. Magenta dots are visited sites where the species was not found; Blue dots, historical sites where the species was confirmed; Green dots historical occurrences that were not visited or found during the 2021 survey. Such sites do not seem to have adequate environmental characteristics to host Circular-leaved Peat Moss. Map created by Maurane Bourgouin and Marion Barbé.

Habitat

Habitat requirements

In the United States, Circular-leaved Peat Moss prefers open to semi-open habitats such as peatlands, grassy savannas, and pine or oak barrens, that is, grass-dominated wetlands with a partially closed tree canopy, primarily composed of pines and oaks (McCormick 1998; Forman 2012). Within these habitats, the species is found at the edges of ditches and sandy roads that are submerged for part of the year, or in peaty depressions in open to semi-open peatlands that dry up in the summer (Flora of North America Editorial Committee 2007; Knapp and McAvoy 2012; Clapp and Neily 2017). The species’ substrate preferences are mixed, and it has been found growing in acid soils in pine stands as well as in calcareous sandy soils or on dried and/or dead peat. In North America, it has been recorded at low to moderate elevations (herbarium surveys: 15 m to 600 m [Bryophyte Portal 2020; ACCDC 2023; Mid-Atlantic Herbaria Consortium 2023]). In South America, it can be found at significantly higher elevations (Bryophyte Portal 2020). In Nova Scotia, it is known only from permanently submerged or very wet depressions, for example, the flooded ditch at the Bloody Creek occurrence (Figure 8). The species occurs at sites with a pH between 3.8 and 4.7.

There is no evidence indicating that Circular-leaved Peat Moss may be associated with regular small-scale disturbances in Nova Scotia. The microhabitats where the species was observed were predominantly open shallow depressions (often between Sphagnum hummocks), where only a small number of species were present (a few companion Sphagnum mosses and Drosera spp., Table 1). The depressions are likely natural, resulting from differential growth and niche partitioning of the different Sphagnum species inhabiting the bog. Circular-leaved Peat Moss may be found in these depressions because of a relatively high resilience to water level fluctuations, from flooded conditions in spring to dry conditions in late summer and autumn.

Figure 8. Colony located in a deep ditch along the edge of Bloody Creek peatland (Photos: Maurane Bourgouin and Marion Barbé).

Habitat trends

The sites surveyed in September 2021 where the species was found are the same as those recorded in the herbarium (herbarium records date from 1973 to 2012). Recent habitat trends are unknown. However, the presence of many moribund colonies strongly suggests that the species has been affected by recent drought. Future declines in habitat quality are inferred because of droughts and fire resulting from global warming.

Biology

The following information on the biology of Circular-leaved Peat Moss comes from the Flora of North America (FNA) (Flora of North America Editorial Committee 2007), and from field studies by Knapp and McAvoy (2012) and Clapp and Neily (2017).

Life cycle and reproduction

Circular-leaved Peat Moss is dioicous, with male and female inflorescences (perichaetia) located on different plants.

Sexual reproduction is rare in Circular-leaved Peat Moss, and few fertile individuals have been observed (Harvey and Maass 1978). No information has been found on the presence of this species in spore banks. Vegetative fragmentation seems to be the predominant mode of reproduction in this species (Karlin 2020).

Circular-leaved Peat Moss fits the description of a long-lived perennial, according to life-history strategy classification theory for bryophytes (During 1992). In the absence of species-specific data, this type of bryophyte can be assumed to have a generation time of about 11 to 25 years (Bergamini et al., 2019).

The species’ reproductive phenology, hybridization potential, fertility, dormancy, population structure, and age at first reproduction are unknown.

Physiology and adaptability

There is no information on Circular-leaved Peat Moss’s physiological requirements and tolerances, although it is presumed to be adaptable and morphologically plastic (based on the different phenotypes observed in moist and dry conditions) as is the case for other Sphagnum species and bryophytes in general. This enables it to survive in temporarily suboptimal conditions (for example, high temperatures leading to the temporary drying of depressions in which it occurs). A wet and acidic microhabitat is probably necessary, at least for the establishment of the species (Hájek and Vicherová 2014).

In addition, spore structure in Sphagnum allows for delayed germination when environmental conditions are unfavourable and spore capsules can tolerate being buried (Sundberg and Rydin 2000).

Because Circular-leaved Peat Moss has been found in habitats where fire is common, moderate heat could stimulate spore germination in the species, as has been reported for other species of Sphagnum (Yusup et al. 2022). Species found in hollows demonstrated a greater ability to develop desiccation tolerance (Hájek and Vicherová 2014) and a stronger positive germination response to heat (Yusup et al. 2022). Nevertheless, prolonged drought (Gerdol and Vicentini 2011) and very high temperatures (over 60°C) are detrimental to Sphagnum species (Yusup et al. 2022), and Circular-leaved Peat Moss is no exception.

Dispersal and migration

The limited geographic distribution of species in the section Subsecunda, such as Circular-leaved Peat Moss, suggests that they have limited dispersal capacities. Sporophytes are rarely produced in Circular-leaved Peat Moss (McQueen and Andrus 2007), which may be attributable in part to the species being dioicous, with male and female plants occurring separately in different subpopulations. Furthermore, they are morphologically atypical in that their capsules are narrow walled and immersed in the leaves, and they have few to no pseudostomata, which participate in contraction of the capsule allowing the spores to be ejected (Andrews 1960; Sundberg 2009). The lack of pseudostomata, the physical barrier formed by the apical leaves, and the rarity of sporophyte production suggest that even when spores are produced, they have little chance of being ejected into the atmosphere to facilitate inter-patch dispersal.

Circular-leaved Peat Moss is presumed, like other bryophytes (Glime 2007, Barbé et al. 2016), to be mainly dispersed passively, through wind (anemochory) and water (hydrochory) (Glime 2007). Transport through active dispersal mechanisms (zoochory), which has been recorded in some bryophyte species, may also be possible. When the peatland is wet and the water level is high, passive dispersal by hydrochory could allow the species to colonize nearby depressions, thus ensuring the survival or even expansion of a given occurrence. However, during dry periods, depressions are likely to be more isolated, limiting passive dispersal.

Two of the occurrences (Bloody Creek and Quinns Meadow) are connected by a network of wetlands. They are 5.2 km apart and are separated by a mosaic of Crown forest land and peatland/wetland habitats. It is possible that the species could colonize areas near the currently known occurrences by dispersing along the Clyde River. However, the likelihood of this type of colonization would depend on disturbance events, because the adjacent peatlands appear to be too closed and densely colonized by other plants to allow Circular-leaved Peat Moss to establish.

A detailed study of the species’ reproductive parameters will likely be needed to test these assumptions, because no fruiting Canadian individuals have been observed either in the field or in herbarium specimens. This situation could be attributable in part to the fact that fruiting does not occur in late summer or fall (no sporophytes of other Sphagnum species were observed during the fieldwork), that the species does not reproduce at the northern edge of its distribution, or that the species primarily reproduces vegetatively (asexual reproduction by fragmentation). However, there have been no documented events of dispersal of asexual propagules. Understanding the species’ dispersal pattern is essential, because the shoots found in the depressions scattered here and there in a peatland are very small in size (often limited to a few individuals / shoots), and their demise could rapidly lead to the complete extirpation of a subpopulation in a given site.

Interspecific relations

No interspecific interactions involving this species have been reported, although predation (for example, browsing, use for nests and shelters) is possible (Glime 2020). Circular-leaved Peat Moss is sometimes found (4/14 depressions) in a mixture with other more conventional branched species such as Sphagnum cuspidatum.

Population sizes and trends

Population sizes and trends in Circular-leaved Peat Moss in North America are unknown (the U.S. experts contacted had no information on this subject).

Maass was the first to collect Circular-leaved Peat Moss in Canada in Nova Scotia “from a few localities newly discovered in 1973 and 1974 (Maass et al., unpublished)” (Harvey and Maass 1978). Harvey and Maass (1978) also documented the presence of Circular-leaved Peat Moss growing with Sphagnum pylaesii along the Clyde River Road. These historical samples from NSPM and NBM (Table 1) have locality descriptions of limited accuracy and precision because GPS technology was not available when they were first described. Despite this, the most likely candidate sources for these samples have been visited, and the writers of this COSEWIC report are confident that two sites, Quinns Meadow and Pug Lake (NSPM collection #10950), are still extant.

As of 2024, three sites with Circular-leaved Peat Moss have been found: Quinns Meadow Conservation Area ([Maass collection, Andrus collection, Clapp and Neily [2017], this report); Bloody Creek (Clapp and Neily [2017], this report) and Pug Lake (Maass collection, this report).

In total, 14 to 168 individuals of Circular-leaved Peat Moss were known from Canada in 2024, following the 2023 Shelburne County wildfire (Figure 9). On the basis of colony size, these can be assumed to be “mature individuals,” but reproductive maturity remains undocumented at present. The number of depressions (each of which houses a colony) is used as a proxy for the number of individuals, following the recommendations of Bergamini et al. (2019). Detailed information on the existing Circular-leaved Peat Moss sites is provided below.

The Quinns Meadow Conservation Lands (designated as such in 2009, total area of 405 ha) is an open wet peatland, accessible only by canoe, where there are trees with fire traces on the peatland edge. Two colonies were found in partially or completely dried-up depressions along the treed peatland edge (QMCL1 and QMCL2, Figure 10). These colonies were 70 m apart. Both colonies (QMCL1 and QMCL2) are within the footprint of the 2023 Shelburne County wildfire (Figure 9): one colony was completely consumed, and only a few shoots remain in the other. However, a third colony (QMCL3), described by Clapp and Neily (2017), was not affected by the fire and is still in good health. It covers an area of 50 m² and is dominated by Circular-leaved Peat Moss (Haughian pers. comm. 2024).

Figure 9. Burned areas and aerial fire-retardant drop sites from 2023 Shelburne County fire, shown with extant Circular-leaved Peat Moss occurrences. The map was created by Maurane Bourgouin and Marion Barbé using fire extent polygons compiled by Marcel Morin, Lost Art Cartography.

Figure 10. Peatland on the Quinns Meadow Conservation Lands (Photo: Maurane Bourgouin and Marion Barbé).

The Bloody Creek site is a fairly dry, open peatland near a sandpit with trees (mainly spruce) bearing fire traces along the peatland edge. The colonies were 60 m apart on average.

A total of 12 colonies were found:

• one colony in a 1-m-deep ditch, where the species is dominant (by percent cover) and healthy (large individuals) (BC1, Figure 8). This ditch, unlike others in the peatland, is likely anthropogenic in origin as it was probably dug as a firebreak (Neily pers. comm. 2021).
• 11 colonies located in partially or completely dried depressions along the treed peatland edge (BC2 to BC9, Figure 11).

Figure 11. Circular-leaved Peat Moss colonies (BC2 to BC9 – partially dried-up depressions in Bloody Creek peatland). Photos: Maurane Bourgouin and Marion Barbé.

The Pug Lake Road site (Pug Lake, Figure 12) is a dried-up, open peatland that has visible fire scars (Figure 13); a portion of it is dominated by shrubs and tall heath species. The age of the fire scars is unknown. The single Circular-leaved Peat Moss colony was found on the peatland edge in a wet, open depression with a substrate of decomposed peat and a sparse heath cover.

Visits to other sites described in herbarium collections from the New Brunswick Museum (NBM) and the Nova Scotia Museum of Natural History (NSPM) failed to locate Circular-leaved Peat Moss colonies. It is unlikely that colonies exist in some of these sites currently as they are not suitable habitats for the species. They consist of alder-lined ditches, dried-up depressions below roadside ditches and dense peatlands (Table 1). It could be that the positions listed were inaccurate. Furthermore, the exact positions of many of the sites mentioned on herbarium specimens in the NSPM collection are very hard to establish. Two sites, one near Middle Clyde River and one on the north shore of the Beaverdam Lake, were mentioned in a specimen in the NBM collection that was not visited but could potentially contain the species.

Figure 12. Circular-leaved Peat Moss colony in wet depression in Pug Lake peatland (Photos: Maurane Bourgouin and Marion Barbé).

Figure 13. Pug Lake peatland. Fire traces are visible on the trees and a temporary shelter can be seen right on the edge of the peatland (top right). Photo: Maurane Bourgouin and Marion Barbé.

Sampling effort and methods

As mentioned above in Search effort, a simple model of habitat preference was generated. Sites with known colonies, together with sites predicted to have appropriate habitat, were visited within and outside of the Clyde River valley. To refine the surveyors’ understanding of the species’ habitat preferences, less suitable sites for the species were also visited: closed peatlands, river and stream edges, wetlands, and sites that are not sandy or adjacent to pine forests and coastal peatlands.

Once the field team reached the site, the peatland was searched for colonies. When the species was identified in the field, the GPS point, cover percentage (Braun-Blanquet scale [Poore 1955]) and area, vigour (good, that is, well-shaped individuals, several strong stems, bright green to yellowish green, or moribund, that is, tiny stems or fragments, brown and partially decomposed with few green parts, light yellowish green to orange brown tones), and the presence or absence of sporophytes were noted. Vigour was used as a means to assess the state of the colony, that is, as an index of survival potential or habitat quality for the species. Moribund colonies are not necessarily already lost but they have a higher risk of extirpation and may indicate the most likely demographic trajectory. The rest of the peatland was then searched, with a major effort devoted to the treed edges and to accessible microhabitats deemed suitable for the species (that is, open depressions with exposed soil).

The habitat at each site was briefly characterized, including herbaceous vegetation, shrubs and trees, and companion species. Companion bryophyte species were sampled for later identification in the laboratory. To measure the pH, water or peat samples were taken at sites with occurrences and at certain other sites with suitable habitat but no occurrences.

Abundance

Because the presence of Circular-leaved Peat Moss is restricted to shallow depressions in bogs in Nova Scotia, the number of mature individuals can be evaluated as the number of depressions containing the species (that is, colonies of) on each site (following the guidelines in Bergamini et al., 2019). Using this approach, a total of 14 “mature individuals” are currently found in Canada, with 11 consisting of moribund and senescent colonies having only a few scattered and decaying stems. If, however, all stems (regardless of their health condition) in the 11 moribund and senescent colonies are counted, with each such colony having 15 or fewer stems, then the estimated total population is 168 individuals. The Canadian population is thus estimated to be 14 to 168 individuals.

On the Quinns Meadow Conservation Lands, two depressions smaller than 1 m² were found with vigorous individuals accounting for 55% cover of the depressions in 2021 (QMCL1 and QMCL2). The total cover occupied by the species at the Quinns Meadow CL site likely declined between 2017 and 2021 (Clapp and Neily pers. comm. 2021). In 2024 a search confirmed the complete loss of these two colonies following the 2023 Shelburne wildfire (Figure 9). However, on this trip, the third colony, QMCL3, was relocated for the first time since 2017, and had not burned during the fire. This colony is large (50 m²) and contains vigorous Circular-leaved Peat Moss individuals. The site with the highest abundance of individuals (colonies) of the species was Bloody Creek with 12 depressions having colonies of various sizes ranging from very small (trace: less than 3% of the depression) to large (85% cover of the wet depression). The largest depression (124.32 m²) also had the most vigorous individuals. All other depressions at the Bloody Creek site were smaller than 1 m² and contained moribund individuals. Only one 4.8 m² depression was found in the Pug Lake site; it harboured vigorous individuals covering 60% of the depression.

Fluctuations and trends

Searches conducted in 2021 for this report failed to identify any new sites, and some historical occurrences were not relocated. On the basis of this information, it is difficult to conclude that a loss of occurrences has occurred, because the exact localities of occurrences are hard to establish. Therefore, it is unknown whether there has been a decline in extent of occurrence, area of occupancy, or locations since 2021. The 2023 wildfire reduced the number of individuals at one site but did not extirpate the species. Once established on a site, the species is believed to persist until there is a natural shift in habitat quality. This could take many decades. Therefore, there are no extreme fluctuations in subpopulation size, location, occurrences, or area of occupancy. However, many of the individuals (colonies) were moribund and if habitat conditions decline, for instance, as a result of prolonged drought or colonization by other species, it can be inferred that these individuals have been extirpated. Therefore, it is suspected that of the 14 extant individuals (colonies) found in 2024, the 11 individuals that were moribund could become extirpated over the next three generations, resulting in a loss of about 78% of individuals.

Rescue effect

There is little chance of rescue from populations farther south, in the U.S. The nearest occurrence in Massachusetts is approximately 700 km away. This large gap, combined with the species’ limited dispersal ability, suggests a very small possibility of rescue from southern occurrences.

Threats and limiting factors

The threats to Circular-leaved Peat Moss were assessed based on the IUCN-CMP (International Union for Conservation of Nature–Conservation Measures Partnership) unified threats classification system (IUCN and CMP 2006; Salafsky et al. 2008; Master et al. 2009). They are discussed below in decreasing order of impact, ending with those for which impact is unknown (see Appendix 1 for details). The calculated overall threat Impact assigned to Circular-leaved Peat Moss is “Very high-High” (Appendix 1).

The most serious and plausible threats to Circular-leaved Peat Moss include climate change-induced drought and increased frequency of fire. The 2023 fire season highlights the vulnerability of this species to fire. Another important threat is recreational activities (ATV use). The species may also be threatened by quarrying, mining and pollution due to the discharge of garbage and solid waste near occupied sites. In Canada, the species is known from three sites spread over an area of 12 km², considered to be only one location subject to the threat of climate change. The entire Canadian population may therefore be extremely vulnerable to climate change and stochastic events, such as uncontrolled wildfires. However, the effect of several concurrent threats to the species’ dynamics, as well as specific aspects of the species’ biology (generation length, reproduction effort), remain unknown, resulting in an overall assigned threat assessment of “Very high-High” for Circular-leaved Peat Moss.

Climate change and severe weather (threat category 11.2 droughts; impact very high-medium)

Climatic conditions, particularly successive periods of drought, combined with the species’ low dispersal ability, are the main threat to Circular-leaved Peat Moss.

Climate change, particularly the increase in drought events and the generalized drying of peatlands over increasingly long periods, has also been described as an indirect threat to the Nova Scotia population (Neily pers. comm. 2020). An analysis of the Nova Scotia drought of 2016 showed that the counties in southwestern Nova Scotia were most impacted, including Yarmouth County where Circular-leaved Peat Moss is found (Kennedy and Drage 2017). This report also states that: "Although climate change models predict small precipitation increases for the region, they also project more extreme weather events and a 36% increase in summer water deficits (for example, actual – potential evapotranspiration) from the 1980s to the 2050s.” A study by Richards and Daigle (2011) shows an increase in moisture deficits for Yarmouth to 2080 (Table A20, page 60). A similar trend of increasing moisture deficits has been observed for other areas of southwestern Nova Scotia. The large percentage (>78%) of moribund Circular-leaved Peat Moss individuals seen during the fieldwork for this report may be a direct result of the 2016 drought.

While overall precipitation predictions for Nova Scotia show increases in total amounts of precipitation, precipitation events are expected to be less frequent but more intense (Kennedy and Drage 2017). This type of precipitation event can result in more overland runoff and less infiltration into aquifers, which can paradoxically result in increased drought (Kennedy and Drage 2017).

While the natural fire return interval varies considerably across Nova Scotia, it is around 250 years in the area near the occurrences of Circular-leaved Peat Moss. Taylor et al. (2020) reported that fires are expected to increase in the province. The summer of 2023 was a good example of this. Fires may have a positive effect on Circular-leaved Peat Moss distribution as new microhabitats are created and made available for colonization, allowing natural habitat succession to start over. However, the suspected link between the species and fire and other disturbances has yet to be shown.

In the IUCN Threats Calculator, the threat of Climate Change and Severe Weather has a severity of “Extreme-Moderate,” and a timing of “High,” and the entire population of Circular-leaved Peat Moss will be affected. Therefore, the scope is “Pervasive.” The overall threat impact is calculated as “Very high-Medium.” In this category, the most serious and plausible threat to the species is drought, which may lead to natural system modifications such as increased fire frequency and severity, and possibly an acceleration of succession from open wetland to forested wetland (threat category 7.1 and 7.3 respectively).

Other climate threats, linked with the one described above, are Temperature Extremes and Storms and Flooding. The calculated overall impact of those threats is “Unknown,” their scope is considered “Pervasive,” and the Severity and Timing are “Unknown.” Storms and flooding may lead to the species’ extirpation as the entire population is located in the Clyde River basin.

Climate change vulnerability index (Appendix 2)

According to the framework for assessing a species’ vulnerability to climate change proposed by Foden et al. (2013), Circular-leaved Peat Moss should be sensitive to climate change given its narrow environmental tolerance and its rarity. This species also has a reduced adaptive capacity due to its presumably limited intrinsic dispersal potential (see Dispersal and migration) and low microevolution potential (long generation time and low reproduction rate; see Life cycle and reproduction). Furthermore, it is exposed to adverse effects from climate change due to the latter’s impacts on the duration and intensity of droughts and fire regimes. This is particularly true in the fragile habitats where it occurs—peatlands and other wetlands—which are especially vulnerable to climate change (Hengeveld 2000).

A Climate Change Vulnerability Index (CCVI) was completed for Circular-leaved Moss to support the above climate change appraisal in the Threats Assessment. The vulnerability of Circular-leaved Peat Moss was evaluated using the NatureServe Canadian Climate Change Vulnerability Index (NatureServe 2024). The CCVI combines vulnerability information from three components: (1) indirect exposure to climate change, (2) species-specific sensitivity and adaptive capacity (including dispersal ability, temperature and precipitation sensitivity, physical habitat specificity, interspecific interactions, and genetic factors), and (3) the species’ adaptive capacity to withstand environmental changes. Indirect exposure to climate change is measured by examining the projected changes in annual climate moisture deficit across the species’ range within the assessment area in addition to projected changes in mean annual temperature. The result is a numerical sum for the species. The sum is then converted into a categorical score by comparing it to threshold values (Young and Hammerson 2016). The six possible scores from the CCVI are Extremely Vulnerable, Highly Vulnerable, Moderately Vulnerable, Less Vulnerable, and Insufficient Evidence. These results are consistent with the impact score for the “Climate Change and Severe Weather” threat discussed above. The climate data used are derived from the Intergovernmental Panel on Climate Change’s Fifth Assessment Report (IPCC 2013).

The CCVI score for Circular-leaved Peat Moss was Extremely Vulnerable, indicating that the species’ abundance and/or range extent in Canada is extremely likely to substantially decrease or disappear by 2050. This date falls within three generations, using 11 years as the generation time for the species. Confidence in this score was Extremely High.

Natural system modifications (threat category 7.1 fire and fire suppression; impact high-low)

With an increase in fire frequency expected due to climate change (Taylor et al. 2020), an increase in fire suppression activities is also expected. Fire suppression effects can range from the relatively benign application of fresh water to the distribution of salt water or chemicals with effects ranging from fertilization to degradation of vegetation (Backer et al. 2004). The creation of firebreaks and use of “back-burns” or prescribed burns can also involve removal of trees and understorey plants, and may consequently affect both above-ground habitat properties, such as shading, and below-ground properties, such as the flow and availability of nutrients and water (Backer et al. 2004). Among these activities, the direct application of fire suppressants and salt water on Circular-leaved Peat Moss colonies is most likely to have significant negative impacts, because of the species’ association with open freshwater peatlands. In the IUCN Threats Calculator, the fire and fire suppression threat was initially considered to have a pervasive-large scope, unknown severity, and high timing; however, following the severe 2023 wildfire, a severity range of slight (1%) to serious (70%) seems more plausible.

Human intrusions and disturbance (threat category 6.1 recreational activities; impact high-low)

The peatland on the Quinns Meadow Conservation Lands is a conservation area that is isolated and difficult to access (accessible only by canoe or boat). Therefore, no motorized recreational activities are possible at this site. The Bloody Creek and the Pug Lake peatlands are more subject to human intrusions and disturbance from recreational uses. These sites can be directly accessed from a logging road and a dirt road, respectively, and several ATV tracks have been observed on the peatlands.

ATV traffic has caused heavy damage at Pug Lake and Bloody Creek (stripping of peat layer, ruts, related waste; Figure 14). Although ATVs create ruts and potholes that might be suitable for the establishment of the species, this has never actually been observed. The observed tracks seem recent and associated with repeated traffic, but tracks have not been found in the areas containing Circular-leaved Peat Moss. Nonetheless, the use of these peatlands in the future for recreation and vacationing could lead to the complete extirpation of the species from the sites in question if existing colonies are disturbed.

This local threat should not simultaneously affect the three sites where Circular-leaved Peat Moss occurs. In addition, the real effect of recreational activities on Circular-leaved Peat Moss has not been documented. However, ATV disturbance similar to that seen elsewhere in these peatlands (that is, stripping of the upper peat layer) could result in the loss of a Circular-leaved Peat Moss colony. Therefore, in the IUCN Threats Calculator (Appendix 1), the scope of the threat was assessed as “Large-Restricted,” severity as “Serious-Slight,” and timing as “High.” The calculated overall impact of recreation activities on Circular-leaved Peat Moss is “High-Low.” Note that the possible consequences of an oil and gas leak from the use of ATVs are unknown.

Figure 14. Stripping of peat and ruts left by ATVs in a peatland in Woods Harbour (Photos: Maurane Bourgouin and Marion Barbé).

Residential and commercial development (threat category 1.1 housing and urban areas; impact low)

The Pug Lake peatland site is particularly vulnerable to residential and commercial development because part of the peatland has already been filled in (extending roughly 10 m into the peatland), and a trailer is parked there. Anthropogenic development poses a direct threat to the species. The Clyde River area has many homes, temporary shelters, trailers and cottages. Determining if this development constitutes a threat to the species in the long term will require an examination of the land-use plans for the region.

In the IUCN Threats Calculator (Appendix 1), the scope of the threat was assessed as “Small,” severity as “Serious,” and timing as “Moderate.” The calculated overall impact of housing and urban areas on Circular-leaved Peat Moss is “Low.”

Limiting factors

According to Karlin (pers. comm. 2020), the rarity of sexual reproduction in Circular-leaved Peat Moss is likely the reason for the species’ limited expansion. He suspects that the species’ various sites consist of clonal populations resulting from vegetative reproduction, given that the Canadian population is disjunct from the populations found elsewhere in North America.

Neily (pers. comm. 2020) also considers the geographic isolation of the sites and the distance between sites as limiting factors for the species’ expansion in Canada.

Number of locations

Each occurrence of the Circular-leaved Peat Moss is exposed to different localized threats: ATVs in Pug Lake and Bloody Creek, quarrying and garbage waste in Bloody Creek, and accelerated transition to a wooded fen or swamp in Quinns Meadow Nature Reserve (see succession in the Climate Change section). Considering these localized threats, the maximum number of locations is three. Nevertheless, the most significant threat to these species may be climate change-induced droughts and drying of wetlands. These impacts could affect all three subpopulations concurrently because of their close proximity, in which case the number of locations is one. In addition, because much of the potential habitat is in a restricted area (Figure 6), it is quite likely that climate change-induced changes would affect all the subpopulations that may be found there.

Therefore, the number of locations is 1 to 3.

Protection, status and rank

Legal protection and status

Circular-leaved Peat Moss does not have any protected status internationally (it is not listed under the U.S. Endangered Species Act or the Convention on International Trade in Endangered Species of Wild Fauna and Flora [CITES]), nor is it protected at the federal, provincial or territorial levels. To date, it has not been the subject of any protection, recovery, restoration or management measures or actions.

Non-legal status and ranks

Internationally, Circular-leaved Peat Moss has no protected status (it is not on the IUCN Red List of Threatened Species, IUCN 2020).

Globally, the species is ranked Vulnerable (G3; NatureServe Explorer 2023), meaning that it is at moderate risk of extinction or collapse due to a fairly restricted range, relatively few populations or occurrences, recent and widespread declines, threats or other adverse factors (NatureServe Explorer 2023).

In the United States, Circular-leaved Peat Moss is ranked NNR, and at the subnational scale it is ranked as Vulnerable (New Jersey) (S3; NatureServe Explorer 2020) or Apparently Secure (S4; NatureServe Explorer 2020). In Canada, it is designated Critically Imperiled (Nova Scotia, N1 S1; NatureServe Explorer 2020).

It has not been ranked in the other states where it has been recorded (Status Not Ranked).

In South America (Colombia and Brazil), the status of Circular-leaved Peat Moss has not been assessed (González et al. 2016).

Habitat protection or ownership

A portion of Circular-leaved Peat Moss habitat in Nova Scotia is legally protected. The colonies on the Quinns Meadow Conservation Lands (405 ha, established in 2009), which are owned by Nature Conservancy of Canada (Nova Scotia Government 2013). However, since the rates of colonization and decline are unknown, it is not possible to determine whether protecting a single site would be sufficient to ensure the species’ persistence in the study area.

Lastly, since the species’ presence appears to be linked to localized disturbances, it is bound to disappear from some sites after the time interval required for the canopy to close and for more competitive species to colonize the area as part of natural succession. Consequently, even though its habitat is legally protected, Circular-leaved Peat Moss could be extirpated from the habitat during natural forest succession, or as a result of fire and similar disturbance events.

Acknowledgements

The report’s authors would like to thank all the individuals listed in the “Authorities Contacted” and “Information Sources” sections for graciously providing their advice, assistance and networking, which have been extremely useful.

We would particularly like to express our gratitude to Tom Neily and Harold Clapp, who provided extensive advice and comments during our many email exchanges, and also joined us in Nova Scotia to assist us during the fieldwork.

We also thank Kendra Driscoll, Amanda Bremner, Jennifer Doubt, Thomas Neily, William McAvoy, Sean Blaney, Sean Haughian, and Eric Karlin, who provided us with invaluable information on the species, as well as herbarium lists, and allowed us to consult their collections and gain access to specimens of Circular-leaved Peat Moss.

We would also like to thank Sean Basquill for the information he provided on Shelburne County, as well as Frances MacKinnon for assistance in map making.

Lastly, our heartfelt thanks go to Jenny Wu and René Belland, who provided support throughout the writing of this report and contributed greatly to its improvement.

Authorities contacted

• Agafontsev, Mikhail – Ecologist, Tomsk State University (Tomsk, Western Siberia, Russia) – No response
• Arsenault, André – Forest Ecologist, Natural Resources Canada (Corner Brook, Newfoundland and Labrador, Canada) – No response
• Basquill, Sean – Biologist, Nova Scotia Department of Natural Resources (Halifax, Nova Scotia, Canada) – Information on the species in Nova Scotia
• Belland, René – Faculty/Researcher, University of Alberta (Edmonton, Alberta, Canada) – Resource person for mosses and lichens, information on the species, and herbarium lists
• Blaney, Sean – Executive Director, Atlantic Canada Conservation Data Centre (Sackville, New Brunswick, Canada) – Information on sites, ecology, threats and status, and herbarium lists
• Bremner, Amanda – Assistant Curator, Herbarium of the New Brunswick Museum (Saint John, New Brunswick, Canada) – Herbarium lists, consultations, loan of specimens, consultation of W. Maass collection
• Campbell, Christopher – Director, University of Maine Herbarium (Orono, Maine, U.S.A.) – No response
• Clapp, Harold – Mersey Tobeatic Research Institute, non-profit organization (NPO) (Kempt, Nova Scotia, Canada) – Information on his article, sampling method, the species and fieldwork
• Clayden, Stephen – Retired Curator, Herbarium of the New Brunswick Museum (Saint John, New Brunswick, Canada) – No response
• Doubt, Jennifer – Curator, Botany, Canadian Museum of Nature (Ottawa, Ontario/ Quebec, Canada) – Referrals (contacts), digitized herbarium specimens, herbarium lists, loan of specimens
• Driscoll, Kendra – Assistant Curator, Herbarium of the New Brunswick Museum (Saint John, New Brunswick, Canada) – Herbarium lists and consultation
• Durocher, Adam – Data Manager, Atlantic Canada Conservation Data Centre (Sackville, New Brunswick, Canada) – No response
• Faulkner, Sheri – Biologist, Canadian Wildlife Service (Canada) – No response
• Fey, Emmanuelle – Biologist, Canadian Wildlife Service (Canada) – No information
• Filion, Alain – Scientific and GIS Project Officer, COSEWIC Science Support and CITES, Canadian Wildlife Service, Environment and Climate Change Canada
• Harpel, Judith – Adjunct Professor, University of British Columbia (Vancouver, British Columbia, Canada) – UBC Herbarium lists
• Haughian, Sean – Curator, Nova Scotia Museum (Halifax, Nova Scotia, Canada) – Updating of database and consultation of W. Maass collection
• Hébert, Nancy – Biologist, Quebec Department of Environment and the Fight Against Climate Change (MELCC) (Quebec City, Quebec, Canada) – Referral of resource persons
• Humber, Jessica – Ecologist, Government of Canada (Corner Brook, Newfoundland and Labrador, Canada) – Referral of resource persons
• Hurlburt, Donna – Ecologist, Nova Scotia Department of Lands and Forestry (Kentville, Nova Scotia, Canada) – No response
• Kaeser, Christina – Ecosystem Geomatics Specialist, Parks Canada (Gatineau, Quebec, Canada) – No response
• Karlin, Eric – Professor, Ramapo College of New Jersey (Mahwah, New Jersey, U.S.A.) – Duke Herbarium lists; information on status of U.S. populations, habitat preferences, threats and factors limiting expansion
• Kasymov, Denis – Ecologist, Tomsk State University (Tomsk, Western Siberia, Russia) – No response
• Labrecque, Jacques – Botanist, MELCC (Quebec City, Quebec, Canada) – No response
• Lavoie, Gildo – Ecologist, Environment and Climate Change Canada (Quebec City, Quebec, Canada) – No response
• McAvoy, William – Botanist, State of Delaware (Dover, Delaware, U.S.A.) – Information on Delaware sites, habitat preferences, threats
• MacKinnon, Frances – GIS and Remote Sensing Support, Nova Scotia Department of Lands and Forestry, Wildlife Division
• McKnight, Julie – Biologist, Canadian Wildlife Service (Canada) – No response
• Moores, Shelley – Manager, Government of Canada (Corner Brook, Newfoundland and Labrador, Canada) – No response
• Neily, Thomas – Biologist, Mersey Tobeatic Research Institute, NPO (Kempt, Nova Scotia, Canada) – Information on his article, sampling method, the species and fieldwork
• Rivard, Diane – Specimen Preparation and Collection Maintenance, Louis-Marie Herbarium, Laval University (Quebec City, Quebec, Canada) – No response
• Sabine, Mary – Biologist, Hugh John Flemming Forestry Centre (Fredericton, New Brunswick, Canada) – Referral of resource persons
• Sam, Donald – Biologist, Nova Scotia Department of Lands and Forestry (Kentville, Nova Scotia, Canada) – No response
• Seidler, Tristram – Curator, University of Massachusetts Herbarium, Amherst (Amherst, Massachusetts, U.S.A.) – No response
• Shaw, Jon – Professor, Duke University (Durham, North Carolina, U.S.A.) – Access to Bryophyte Portal, information on U.S. sites where species is present and its disjunct range
• Skema, Cindy – Manager, Mid-Atlantic Herbaria Consortium (online) – Herbarium lists
• Struwe, Lena – Professor/Director, Chrysler Herbarium, Rutgers, The State University of New Jersey (New Brunswick, New Jersey, U.S.A.) – Referral of contact persons and access to Bryophyte Portal

Information sources

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Barbé, M., É.E. Chavel, N.J. Fenton, L. Imbeau, M.J. Mazerolle, P. Drapeau, and Y. Bergeron. 2016. Dispersal of bryophytes and ferns is facilitated by small mammals in the boreal forest. Ecoscience 23:67-76.

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Clapp, H., and T. Neily. 2017. Sphagnum cyclophyllum: a second site in Nova Scotia for a rare Sphagnum moss. Evansia 34:6-8.

Clapp, H., and T. Neily. pers. comm. 2021. Email correspondence to M. Bourgouin and M. Barbé. Biologist at Mersey Tobeatic Research Institute, Kempt, Nova Scotia.

During, H.J. 1992. Ecological classifications of bryophytes and lichens. Pp. 2-32, in J.W. Bates and A.M. Farmer (eds.). Bryophytes and lichens in a changing environment, Clarendon Press, Oxford Science Publication.

Environment Canada and Parks Canada Agency. 2015. Amended Recovery Strategy and Management Plan for Multiple Species of Atlantic Coastal Plain Flora in Canada [Proposed]. Species at Risk Act Recovery Strategy Series. Environment Canada and Parks Canada Agency. Ottawa. 141 pp. + appendices.

Flora of North America Editorial Committee. 2007. Flora of North America: Volume 27: Bryophytes, Part 1: Mosses. Oxford University Press.

Foden, W.B., S.H.M. Butchart, S.N. Stuart, J.-C. Vié, H.R. Akçakaya, A. Angulo, L.M. DeVantier, A. Gutsche, E. Turak, L. Cao, S.D. Donner, V. Katariya, R. Bernard, R.A. Holland, A.F. Hughes, S.E. O’Hanlon, S.T. Garnett, C.H. Sekercioglu, and G.M. Mace. 2013 Identifying the world's most climate change vulnerable species: a systematic trait-based assessment of all birds, amphibians and corals. PLoS ONE 8(6): e65427. https://doi.org/10.1371/journal.pone.0065427

Forman, R. 2012. Pine Barrens: Ecosystem and Landscape. Elsevier.

Gerdol, R., and R. Vicentini. 2011. Response to heat stress of populations of two Sphagnum species from alpine bogs at different altitudes. Environmental and Experimental Botany 74:22-30.

Glime, J. 2007. Bryophyte ecology. Ebook sponsored by Michigan Technological University and the International Association of Bryologists. Website: https://digitalcommons.mtu.edu/bryophyte-ecology/ [accessed January 2021].

González, R.B., S.R. Gradstein, and M.C. Pacheco. 2016. Catalogue of the plants and lichens of Colombia. Universidad Nacional de Colombia, Sede Bogotá, Facultad de Ciencias, Instituto de Ciencias Naturales. 3056 pp.

Gray, A. 1862. Characters of some Compositae in the collection of the United States South Pacific exploring expedition under Captain Wilhes.

Hájek, T., and E. Vicherová. 2014. Desiccation tolerance of Sphagnum revisited: a puzzle resolved. Plant Biology 16:765-773.

Hengeveld, H.G. 2000. Projections for Canada's climate future: a discussion of recent simulations with the Canadian Global Climate Model. Environment Canada, Meteorological Service of Canada. Science Assessment and Integration Branch, En57-2000-01E.

Intergovernmental Panel on Climate Change (IPCC). 2013. Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, UK and New York, NY. Available at: https://www.ipcc.ch/report/ar5/wg1/ [accessed Sept. 27, 2023].

IUCN. 2020. International Union for Conservation of Nature. Website: https://www.IUCN.org/ [accessed June 2020].

Karlin, E. pers. comm. 2020. Email correspondence to M. Barbé. Professor at the New Jersey College, Mahwah, New Jersey.

Kasymov, D., and M. Agafontsev. 2016. Experimental study of the influence of ignition source position on the parameters of peat fire propagation. Page 060004 in AIP Conference Proceedings. AIP Publishing LLC.

Kennedy, G.W., and J. Drage. 2017. Development of indices to assess the potential impact of drought to private wells in Nova Scotia in GEO2017. Ottawa, Ontario: Canadian Geotechnical Society. Website: https://novascotia.ca/natr/meb/data/pubs/cs/cs_me_2017-005.pdf [accessed Sept 24,2024].

Knapp, W.M., and W.A. McAvoy. 2012. Sphagnum cyclophyllum new to Delaware and Maryland. Evansia 29:101-103.

McCormick, J. 1998. The vegetation of the New Jersey pine barrens. Pine barrens: ecosystem and landscape.:229-242.

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Mid-Atlantic Herbaria Consortium. 2023. Encyclopedia of Life. National Museum of Natural History. Website: https://midatlanticherbaria.org/portal [accessed February 2020].

NatureServe. 2024. Climate Change Vulnerability Index - Canadian Version. https://www.natureserve.org/products/climate-change-vulnerability-index-canadian-version [accessed Sept. 2024].

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Neily, T. pers. comm. 2020. Email correspondence to M. Bourgouin and M. Barbé. July 2020. Biologist at Mersey Tobeatic Research Institute, Kempt, Nova Scotia.

Neily, T. pers. comm. 2021. Email correspondence to M. Bourgouin and M. Barbé. September 2021. Biologist at Mersey Tobeatic Research Institute, Kempt, Nova Scotia.

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Poore, M. 1955. The use of phytosociological methods in ecological investigations: I. The Braun-Blanquet System. Journal of Ecology 43:226-244.

Richards, W., and R. Daigle. 2011. Scenarios and Guidance for Adaptation to Climate Change and Sea-Level Rise – NS and PEI Municipalities. W. Richards Climate Consulting, Oak Point, NB, 78 p. Website: https://www.novascotia.ca/nse/climate-change/docs/ScenariosGuidance_WilliamsDaigle.pdf [accessed Sept. 24, 2024].

Salafsky, N., D. Salzer, A.J. Stattersfield, C. Hilton-Taylor, R. Neugarten, S.H.M. Butchart, B. Collen, N. Cox, L.L. Master, S. O’Connor, and D. Wilkie. 2008. A standard lexicon for biodiversity conservation: unified classifications of threats and actions. Conservation Biology 22:897-911.

Shaw, J. pers. comm. 2020. Email correspondence to M. Bourgouin. May 2020.

Sundberg, S. 2009. Size matters for violent discharge height and settling speed of Sphagnum spores: important attributes for dispersal potential. Annals of Botany 105:291-300.

Sundberg, S., and H. Rydin. 2000. Experimental evidence for a persistent spore bank in Sphagnum. New Phytologist 148:105-116.

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Young, B.E., and G. Hammerson. 2016. Guidelines for using the NatureServe Climate Change Vulnerability Index. Version 3.0, Canada. NatureServe, Arlington. 61 pages.

Yusup, S., S. Sundberg, B. Fan, M. Sulayman, and Z.-J. Bu. 2022. The response of spore germination of Sphagnum mosses to single and combined fire-related cues. Plants 11:485.

Biographical summary of report writers

Maurane Bourgouin earned her master’s degree in ecology from the Université du Québec en Abitibi-Témiscamingue, specializing in bryology and predictive mapping. Her master’s thesis involved predictive mapping of bryophytes using indices derived from digital terrain models and LiDAR point clouds. This led her to analyze the effects of landscape on the diversity and distribution of bryophytes associated with fragmented landscapes, in the context of timber harvesting. She is currently doing her PhD in biology at the Université de Montréal with a focus on disentangling the taxonomy of the troublesome Bidens taxa of Northeastern North America. She is also a bioecology technician and has implemented numerous sampling protocols in the field, for research on aquatic life, micromammals, entomology, and natural habitat characterization.

Marion Barbé obtained her doctorate in environmental science from the Université du Québec en Abitibi-Témiscamingue in 2017. Specializing in forestry and bryology, she wrote her dissertation on bryophyte community dynamics in Quebec’s black spruce–moss forests. This ultimately involved refining the concepts of residual forest islands and ecosystem-based forest management with the Quebec Department of Forests, Wildlife and Parks (MFFP). Subsequently, she conducted post-doctoral work on the use of bryophytes as climate change indicator species in Quebec (2017 to 2018). As part of this research, she conducted bryophyte inventories in Quebec, the James Bay region, New Brunswick, Alberta, British Columbia, Yukon, the Northwest Territories, and France. She has also worked as an independent bryology consultant for the Quebec Department of Sustainable Development, Environment and the Fight Against Climate Change (MDDELCC), and is currently preparing a field guide to bryophytes with the Société Québécoise de la bryologie.

Collections examined

Consultation of specimens sent by Amanda Bremner (Herbarium of the New Brunswick Museum) to the Laval University Herbarium. [Loan number: NBM loan B2020-13 FW, samples #11988 and #4729].

Appendix 1: Threats calculator assessment for sphagnum cyclophyllum (circular-leaved peat moss)

Species scientific name: Sphagnum cyclophyllum Circular-leaved Peat Moss

Date: 12/13/2022

Assessor(s):

Moderator: Dwayne Leptizki (COSEWIC member) SR writers: Marion Barbé, Maurane Bourgouin, M&L SSC: René Belland (Co-chair), Jennifer Doubt, Karen Golinski, Chris Deduke, Sean Haughian, Toby Spribille, Marc Favreau
Jurisdictions: Donna Hurlburt
External participants: Julie McKnight, Claire Elizabeth Wilson O’Driscoll

References: draft COSEWIC status report and threats calculator

Assigned overall threat impact: Very high - High

Impact adjustment reasons: Not applicable

Overall threat comments: Generation length estimated at 11 to 25 years; therefore timeframe for severity and timing is 33 to 75 years; pop trend unknown; currently known from 3 sites Clyde River area southwestern NS, so; 3 sites ( total 14 individuals, 11 (= 79%) in Bloody Creek, although only 9 shown Appendix 1b states 9 colonies; 2 (= 14%) in Quinns Meadow CL; 1 (= 7%) in Pug Lake; Figure 4 shows distribution.

Appendix 2. Results of the climate change vulnerability index for circular-leaved peat moss

The NatureServe climate change vulnerability index

Release: 3.01 – Canada, January 2016

Version 3.01 (minor bug fix Aug 2021)

Geographic area assessed: Nova Scotia

Assessor: R. Belland, R.Caners, J. Doubt, N. Fenton., C. Robillard, C. Deduke

Species scientific name: Sphagnum cyclophyllym

English name: none

Major taxonomic group: Nonvascular Plant

G-Rank: N1?

Check if the species is an obligate of caves or groundwater systems: S-Rank: not applicable

Check if species is migratory and exposure data can be entered for the migratory range that lies outside of the assessment area:

Assessment Notes (to document special methods and data sources)

Major sources of information for this assessment include: (1) COSEWIC. 2024. COSEWIC status Report on Circular-leaved Moss Sphagnum cyclophyllum in Canada. 2-month Interim Status Report prepared for the Committee on the Status of Endangered Wildlife in Canada. (2) Nature Conservancy Climate Wizard (http://www.climatewizard.org). (3) Young and Hammerson, 2016. Guidelines for using the NatureServe Climate Change Vulnerability Index. Version 3.0, Canada. NatureServe, Arlington.

Exposure: scope estimates (Section A) were based on % of all known sites in Canada exposed to each category of temperature and Climate Moisture Deficit severity, consulting maps included in NatureServe 2024 and the Climate Wizard. Nova Scotia sites = 3/3 sites. 100% Change in Mean Annual Temperature (MAT since 1950s and predicted to 2080s: NS - >2.53 to 2.84°C warmer. Change in Climate Moisture Deficit (CMS) for the same period: NS - >3.23 to 21.04 mm.

Sources for these trends: Young and Hammerson 2016 Figures 2,3,5,6. Figure 6 also used for historical hydrological niche (C2bi).

Section A: Exposure to local climate change (calculate for species' range within assessment area)

Section B: Indirect exposure to climate change (evaluate for specific geographical area under consideration)

Mark an "X" in all boxes that apply.

Comments: Species at the northern limit of range. Cabot Strait will limit northern expansion as well as lack of habitat.

Factors that influence vulnerability (* at least three required)

1. Exposure to sea level rise
2. Distribution relative to barriers
   1. Natural barriers
   2. Anthropogenic barriers
3. Predicted impact of land use changes resulting from human responses to climate change

Section C: Sensitivity and adaptive capacity

Mark an "X" in all boxes that apply.

Check up to three boxes per factor.

Factors that influence vulnerability (* at least 10 required)

1. Dispersal and movements
2. Predicted sensitivity to temperature and moisture changes
   1. Predicted sensitivity to changes in temperature
      1. historical thermal niche
      2. physiological thermal niche
   2. Predicted sensitivity to changes in precipitation, hydrology, or moisture regime) historical hydrological niche
      1. physiological hydrological niche
   3. Dependence on a specific disturbance regime likely to be impacted by climate change
   4. Dependence on ice, ice-edge, permafrost, or snow-cover habitats
3. Restriction to uncommon landscape/geological features or derivatives
4. Interspecific interactions
   1. Dependence on other species to generate required habitat
   2. Dietary versatility (animals only)
   3. Pollinator versatility (plants only)
   4. Dependence on other species for propagule dispersal
   5. Sensitivity to pathogens or natural enemies
   6. Sensitivity to competition from native or non-native species
   7. Forms part of an interspecific interaction not covered by 4a-f
5. Genetic factors
   1. Measured genetic variation
   2. Occurrence of bottlenecks in recent evolutionary history (use only if 5a is "unknown")
   3. Reproductive system (plants only; use only if C5a and C5b are “unknown”)
6. Phenological response to changing seasonal temperature and precipitation dynamics.

Section D: Documented or modeled response to climate change (optional; may apply across the range of a species)

Mark an "X" in all boxes that apply

Comments: Not applicable

Climate change vulnerability index for Sphagnum cyclophyllum in Nova Scotia

Extremely vulnerable: Not applicable

Confidence in vulnerability index score: Very high

Data completeness

Section B: 4/4 factors

Section C: 12/16 factors

Section D: 0/4 factors

Scores are less reliable with more unscored factors

Climate exposure in migratory range: Not applicable

Results of a Monte Carlo simulation (1000 runs) of the data entered in the Index.

Definitions of index values

Extremely Vulnerable (EV):

Abundance and/or range extent within geographical area assessed as extremely likely to substantially decrease or disappear by 2050.

Highly Vulnerable (HV):

Abundance and/or range extent within geographical area assessed as likely to decrease significantly by 2050.

Moderately Vulnerable (MV):

Abundance and/or range extent within geographical area assessed as likely to decrease by 2050.

Less Vulnerable (LV):

Available evidence does not suggest that abundance and/or range extent within the geographical area assessed will change (increase/decrease) substantially by 2050. Actual range boundaries may change.

Insufficient Evidence (IE):

Information entered about a species' vulnerability is inadequate to calculate an Index score.