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COSEWIC assessment and status report on the Boreal Felt Lichen in Canada
- Assessment Summary
- Executive Summary
- COSEWIC Mandate, Membership and Definitions
- List of Figures
- Species Information
- Population Numbers, Sizes and Trends
- Limiting Factors and Threats
- Special Significance of the Species
- Existing Protection or Other Status
- Summary of Status Report
- Technical Summary
- Acknowledgements, Literature Cited, and The Authors
Population Numbers, Sizes and Trends
- New Brunswick
- Nova Scotia
- Population Trends on Black Spruce
- A Note on the Misinterpretation of “Numbers”
The numbers of thalli of E. pedicellatum in the Maritime Provinces and insular Newfoundland have been summarized for the periods before 1995 and after 1994 and are provided below
Only about 10 thalli were documented in 1902 from the original collection locality on Campobello Island. No thalli have been found at the type locality since the original occurrence of this species in New Brunswick became more widely known through the publication by Jørgensen (1972).
The total number of thalli counted before 1995 in Nova Scotia had been 169. Of these, two had been found on the trunks of red maple, one on the fairly thick branch of a white spruce and one on a thin branch of balsam fir. The remaining 165 thalli occurred on the trunks of 102 balsam firs. The average number of thalli per trunk of balsam fir was therefore approximately 1.6. The total number of thalli that could be located in Nova Scotia in the late 90s was only 13, amounting to a reduction in numbers by about 92%. Accordingly, the total number of balsam fir trees colonized had shrunk from 102 to 7. It had been hoped that the habitat in the Moser River Valley (loc. NS-27) would have had the potential of maintaining itself for another ten or more years, since the present thallus to tree ratio was close to 2 per tree and since the habitat was relatively sheltered against receiving pollutants from the road. In spite of the high humidity at the site, caused by moisture rising from the adjacent swampy and wooded bottom of the river valley, the entire population had collapsed by the end of September 2002.
Within only a couple of years after 1979, when the senior author had begun to search for the presence of E. pedicellatum in all accessible suitable habitats of Nova Scotia, the lichen had disappeared from the southern parts of the province, even though the respective habitats had remained intact upon superficial inspection. Of the 46 localities originally found in Nova Scotia, only 3 localities (NS-12, NS-16 and NS-27, all in the eastern sub-coastal parts of Halifax County) have retained a viable habitat. Degraded habitats include all of those that had originally contained between 9 and 20 thalli.
Only 2 thalli had been encountered on branches, both of these in the most humid parts of the lowlands of Cape Breton Island. One had occurred on balsam fir near Enon (in loc. NS-43) and one on a white spruce in a very moist valley habitat (loc. NS-42). Two other exceptional occurrences had been on the trunks of red maple (locs. NS-6 and NS-46).
The population counts for the Island of Newfoundland are summarized below. Supplementary data compiled by provincial foresters based on fieldwork conducted in early 2002 subsequent to the completion of this report are now also included in this final draft. [This supplementary information of thalli counts was provided to COSEWIC members by the range jurisdiction representatives during discussions on status designation.]
Areas and Significant Populations
Occurrences of Erioderma pedicellatum have been documented in the following geographical areas of Newfoundland (in progressive order from Northwest to Southeast).
Area 1: GreatNorthern Peninsula (western slope)
A total of 23 thalli were recorded before 1995 and only 3 after 1994, all on balsam fir.
Area 2: Burgeo Road (northern areas)
Only 22 thalli have been documented on balsam fir and 1 thallus on black spruce between the Trans Canada Highway and Peter Strides Pond, all before 1995.
Area 3: Burgeo Road (Headlands of Grandy Brook)
Boreal felt lichen was only recorded after 1994 in this area; 88 thalli were found on balsam fir.
Area 4: South Central Newfoundland
This area includes regions between Great Burnt Lake, the Twin Brooks area to the Northwest of Hwy. 362, Jipujijkuei Kuespem Park, Hermitage Bay and Belle Bay areas (280 thalli on balsam fir, 199 on black spruce and 4 on red maple, for a total of 483 before 1995; 2671 thalli on balsam fir and 5 on black spruce for a total of 2675 found after 1994. [Additional surveys by provincial foresters on 13th and 14th of March 2002 in Jipujijkuei Kuespem Park added 1068 more thalli (1065 on balsam fir and 3 on white birch). Also, new surveys on 12th and 15th March, 2002 added 746 new thalli to the Salt Pit-Twin Brooks area, all found on balsam fir (pers. com. to Natalie Djan-Chekar from Bill Clarke, Forestry & Wildlife, 25 Apr. 2002). This totals about 4489 thalli in this region found after 1994.]
Salt Pit - Twin Brooks Road Population
The habitat for this population is about 3-4 km inland from Head of Bay D’Espoir and within about 1 km to the Northwest from Hwy. 361. The population number of 518 thalli is based on counts made by members of Newfoundland and Labrador Department of Forest Resources and Agrifoods (NFS). This area is not likely to receive protection of any kind, since intensive logging operations are being carried out in the general area on a continuing basis. The six sub-sites occupy an area of about 2 km2. Some of the studies by Robertson (1998) have highlighted wave forests where well-illuminated niches are created that may or may not become subsequently colonized by E. pedicellatum
Jipujijkuei Kuespem Park Population
The total number of E. pedicellatum thalli encountered within the former boundaries of the Park on balsam fir is 2107, and the approximate number of trees colonized is ~1088, which corresponds to a ratio of about 2 thalli / tree. The potential E. pedicellatum habitats in the Park cover an area up to 4 000 000 m2. So far, 13 more or less discrete sub-sites with a minimum of 30 thalli in each have been studied, which includes all areas on both sides of the River Pond. The most recent survey is that by Yetman (1999) who discovered a relatively juvenile habitat of 201 thalli on balsam fir in a former gravel pit that may have been used for the construction of Hwy. 360. The respective sub-site (NF-21b) contained 57 % juveniles. In general out of the 1021 thalli found here, 33.1% (338) are juvenile. This is an exceptionally high percentage compared to other populations in Newfoundland. The survival rate of these 338 immature thalli to spore-bearing maturity cannot be determined. However, the importance of their presence is that they attest to the healthy condition of the free-living forms of the Scytonema in these forests during those years when the immature thalli had been formed. Obviously, the creation of these juveniles demanded relatively pollution-free conditions.
There is a mix of serious and relatively minor threats in the Park, when considering other areas in Newfoundland. Moose browsing does occur in the Park but has not become as serious a factor as in Lockyer’s Waters. In contrast, however, aerial spraying of pesticides can be harmful to E. pedicellatum and has in the past been considered for this area.
Area 5: Burin Peninsula
This includes the peninsula and nearby islands in the Placentia Bay; 12 thalli were recorded on balsam fir and 1 thallus on the trunk of a white spruce before 1995 and 11 thalli after 1994, without specific information on substrates.
Area 6: East Central Newfoundland
This is the pond-rich sub-oceanic Bay-du-Nord Wilderness area that had not been visited before 1995, and the areas between Glovertown and Come-By-Chance; 125 thalli were recorded on balsam fir, mostly near Goobies, before 1995 and 128 thalli, all in the Bay-du-Nord lake district, after 1994.
Bay-du-Nord Wilderness Reserve Population
Habitats are located about 58 - 63 km to the West of Clarenville and North East of Meta Pond. They are distributed over 6 sites that contain altogether 16 sub-sites. The total number of thalli recorded for this Reserve was 128. The total area within which these newly found populations of E. pedicellatum were encountered lies within an area approximately 28.25 km2. Of the nearly 30 km2 mentioned, much of the land is occupied by heath-lands and rocky barrens, thereby giving a more approximate estimation of less than 15 km2. Based on this type of calculation for habitat size and considering our preliminary knowledge of this area, it remains a matter of uncertainty whether the Bay-Du-Nord Wilderness area should be considered as one of the major habitats or whether it is not better treated as a large area with numerous meta-populations.
Area 7: Avalon Peninsula
Lockyer’s Waters Population
The total count of thalli in the Lockyer’s Waters by the end of 1997 had surpassed 900; these had been found on close to 500 balsam fir trees, within 10 subsites (McHugh, 1998). This count has recently been adjusted to 953 (Yetman, 1999). The average ratio of thalli of E. pedicellatum on the occupied trees in the Lockyer’s Waters was close to 2:1.
Nine well-established and distinctly different sub-populations with respect to exposure, stand age and canopy density are present (McHugh, 1998). These sites cover an area of about 20 hectares whilst the trees themselves bearing Erioderma would cover only 5.54 hectares. Important long-term research in these areas is presently being conducted in order to learn more about the life cycle of Erioderma and the impact of environmental stress.
A number of factors currently threaten the population. First, the remote area to the southeast of Lockyer’s Waters is surrounded by cottage country (with over 1500 cottages). Second, the high density of moose in the area has stunted the regrowth of suitable stands of balsam fir for recolonization by second-generation Erioderma thalli. Third, during windstorms from a southwesterly direction, pollutants from the industrial areas of Holyrood may reach the wooded hills of Lockyer’s Waters and affect some of the populations of the lichen on northwesterly exposed slopes. And finally, the threat of logging in the area is still of concern. In 1997, logging was halted pending status designation for Erioderma pedicellatum by COSEWIC. Despite this interim protective measure, the future use of Lockyer’s Waters forests has not been determined.
Ripple Pond Ridge Road Population
Ripple Pond Ridge Road, which was built in 1997 for the purpose of salvaging wind-fallen timber, is about 3.5 km long and contains some very steep sections. The E. pedicellatum sites recorded (NF-80x to NF-80e) are discontinuously distributed along the length of this road, the great majority of them are within only a 50 m distance from the road. For an estimation of the area covered by these sub-populations, a 200 m broad strip of land was chosen as the basis for the following calculation: 3 500 m x 200 m = 700 000. A total of about 350 thalli had been present originally, including 18 thalli on black spruce. This is or was the second largest habitat for occurrences of E. pedicellatum on black spruce during the period after 1994. It is uncertain what impact logging operations will have on the long-term survival of this population.
Ripple Pond Population
Two sub-populations (NF-79a and NF-79b) were found in the woodlands about 300-350 m behind the western shores of Ripple Pond, more exactly 150-200 m to the Southwest and Northeast of a small pond which is located about halfway between the Ripple Pond and a narrow strip of sloping peatland to the West. The sub-populations are about 600 m apart from one another and contain a total of 154 thalli. The habitats for E. pedicellatum cover areas up to 300 000 m2 (= 0.3 km2).
Ninth Fox Pond Population
The two sub-sites combined contain 95 thalli on 70 trees of balsam fir and 39 thalli on the branches of 9 trees of black spruce. The area covered by the two sub-sites is about 100 000 m2. In the lower part of sub-site NF-80w some manual thinning had been carried out that might provide a future experimental research site.
Noseworthy’s Gully Population
Behind the East side of Noseworthy’s Gully or Pond lies site NF-81b. It consists of an interesting mosaic of fens and forest habitats on a mix of level ground and slopes (Ringius 1997; Robertson 1998). Here, 122 thalli of E. pedicellatum have been seen on an estimated number of 65 trees of balsam fir in one locality, and a few thalli on several trees of black spruce. The habitats encompass a total area of about 200 x 200 m (4 ha).
As a matter of curiosity, a few thalli have been found much farther to the north at Pegs Pond on the Carbonear Line (loc. NF-84).
The total count of thalli seen or recorded on the Avalon Peninsula during the past 3-4 years is 2148 (i.e., 2085 on balsam fir and 63 on black spruce), whereas before 1995 it was 107 thalli (19 on black spruce). This difference reflects the intensified search for this lichen in the woodlands of Newfoundland since 1996.
A revised total count for Newfoundland, including discoveries in March 2002, amounts to just under 6900 extant thalli. With many suitable habitats remaining in unexplored remote areas of the southern coast of insular Newfoundland, it is anticipated that there may be many more extant thalli.
Comparing Newfoundland’s Two Largest Populations
A comparison between the two largest populations of E. pedicellatum in Newfoundland sheds some light on the chances for long-term survival of the species. The largest and healthiest population occurs within Jipujijkuei Kuespem Park. The Park, excluding small adjacent populations to the North and East, has a total of 2112 thalli (including 5 morbid thalli on black spruce). When considering only populations of thalli in which distinctions were made between adult and juvenile thalli, the percentage of juveniles is 31.75% (327:1030 = x100). Perhaps anomalous to the trend was the high percentage of juveniles (57%) encountered by Yetman (1999) in subsite NF-21b. [NFS new records for this park found on 13th and 15th March, 2002 total 1068 thalli (pers. com. Newfoundland Forest Service)]
In comparison, the populations in Lockyer’s Waters consist of 952 thalli on balsam fir and 1 dead thallus on black spruce. According to data provided by McHugh (1998), 165 juveniles and 698 mature thalli had been documented in “sites 1 to 9”. Upon applying the same ratio to the updated figure for thalli found on balsam fir (952), the total number of juveniles in Lockyer’s Waters may be close to 182.
The Jipujijkuei Kuespem Park contains more than twice the number of thalli on balsam fir (2107) as compared to those that are present in Lockyer’s Waters on the same substrate (952). Approximately 31.75 % of those in the Jipujijkuei are juveniles, which translates into 669 young thalli, on the basis of extrapolations. This means that there are ~3.7 times more young thalli in the Jipujijkuei Kuespem Park than in Lockyer’s Waters. This figure, in the absence of mortality, reflects the possibility of long-term survival of the species in Jipujijkuei Kuespem Park.
Because of the heightened air pollution sensitivity of the lichen on this substrate the health and long-term persistence of thalli on spruces is in question (see Limiting Factors).
In former times, under largely pollution-free conditions, black spruce trees served as much better substrates for colonization by E. pedicellatum than presently. In the early 1980s, the average size of the colonies of E. pedicellatum on individual black spruces was nearly 4 times greater than the colonies on individual balsam fir trees. For instance, at least 50 healthy thalli had been observed on a single spruce in sub-site NF-27a of which 40% had been juveniles. The largest number of thalli observed on the trunk of a single balsam fir had been 16 (in site NF-15). Before 1995, 28.3% of the thalli found were on black spruce, whereas after 1994, only 1.5% of the thalli occurred on the same substrate.
The occurrences of E. pedicellatum on the black spruces of Newfoundland is therefore a good monitoring system to forecast problems in the environment that may become a threat to the long-term survival of the species as a whole, especially regarding air pollution. It is particularly important to maintain records on the health status of E. pedicellatum on this particular substrate.
There is a misconception as population numbers grow, as with E. pedicellatum, that the species is well distributed, essentially “everywhere”. It is appropriate, however; to take a more cautious approach in assessing the present situation. Thallus counts, as with all population assessments, are by no means static entities. This is particularly true when data are accumulated over a short period of time (1996-1999). This scenario becomes more complicated when populations are not distinct and therefore sub and meta-populations exist. For example, localities in Nova Scotia with meta-populations containing up to 20 thalli have been lost within only ten years. True to the nature of meta-population biology, such isolated and therefore vulnerable minor occurrences hold little hope for the long-term survival of the species.
Aside from that, no one can control and maintain the well-being of small populations, even with the best of intentions. The intimate cross-connections between the life-cycles of E. pedicellatum, Scytonema, Frullania and their host trees is a very vulnerable system that is difficult to conserve. We are far from understanding the population dynamics of this species and its complex ecological requirements.
Therefore, our present assessment of the status of Erioderma pedicellatum in Newfoundland is that it is a highly threatened species, not so much in terms of its present thallus numbers but largely in consideration of the outstanding vulnerability of this lichen and of its cyanobacterial symbiont towards air pollutants, global warming and clear cutting operations. Much more needs to be learned to fill in the enormous gaps in our current knowledge about the complexity of the life-cycle of E. pedicellatum, upon which the survival of this lichen depends.
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