Seaside Centipede Lichen
Scientific Name: Heterodermia sitchensis
Other/Previous Names: Seaside Centipede
Taxonomy Group: Lichens
COSEWIC Range: British Columbia
COSEWIC Assessment Date and Status Change: May 2021
COSEWIC Status: Threatened
COSEWIC Status Criteria: B1ab(iii,v)+2ab(iii,v); D1
COSEWIC Reason for Designation: This leafy lichen is known from 20 occurrences on the west coast of Vancouver Island, Canada, and from two in the US. It has highly specific habitat requirements and grows only on partially defoliated small-diameter Sitka Spruce twigs on trees, close to the shoreline, that often receive nitrogen enrichment from sea lion haul-out sites or bird nest sites. The number of mature individuals (thalli) is thought to be less than 1000, and the lichen is highly vulnerable to intense storm activity associated with climate change that destroys the twigs upon which the lichen is found. The change of status from Endangered reflects increased knowledge of the distribution as a result of increased survey effort.
COSEWIC History of Status Designation: Designated Endangered in April 1996. Status re-examined and confirmed in May 2000 and in April 2006. Status re-examined and designated Threatened in May 2021.
SARA Status: Schedule 1, Endangered
Date of Listing (yyyy-mm-dd): 2003-06-05
Please note that this information is provided for general information purposes only. For the most up to date and accurate list of species listed under the Species at Risk Act, please see the Justice Laws Website.
Image of Seaside Centipede Lichen
Seaside Centipede Lichen is a semi-erect, leafy lichen that is shaped like a cushion. On average, this tiny lichen grows to 2 cm in width. The lobes are thin, stiff, separate and irregularly branched. The highly convex upper surface of the Seaside Centipede Lichen is a pale greenish white with a few scattered whitish spots. The lower surface is white and cottony. This species can be recognized by the presence of long, hair-like structures along the edges of its lobes and by the small urn-shaped structures near the tips of its lobes. The urns have prominent flaring rims and the inner surfaces of these rims are covered with numerous soredia (powdery reproductive structures).
Distribution and Population
Seaside Centipede Lichen is found only in coastal British Columbia and Oregon. The United States population consists of a single small and isolated population at Cape Lookout. In Canada, this species occurs from the Pacific Rim National Park Reserve to an area 210 km north of Vancouver Island. To date, it has only been recorded in 12 sites, 10 of which are in or near the Pacific Rim National Park Reserve. The two other sites are near the village of Kyuquot. The two original populations, i.e., the Ucluth Peninsula population near the northern tip of Ucluelet and the Schooner Cove population in the Pacific Rim National Park Reserve, have now disappeared. Based on counts performed from 2001 to 2004, the Canadian population of the Seaside Centipede Lichen comprises 211 thalli spread out over 10 confirmed sites, with 65% of all individuals concentrated in two sites, the Florencia and Wouwer island sites in the Pacific Rim National Park Reserve and the site in the Kyuquot region. Depending on the intensity of winter storms, population sizes can vary significantly from year to year. However, long-term trends in population size have not yet been documented.
In Canada, the Seaside Centipede Lichen is limited to the old-growth Western Hemlock forests along the west coast of Vancouver Island. This species will only grow on the nitrogen-rich lower branches of Sitka Spruce trees. This lichen has very specific habitat requirements. Its presence appears to depend on the convergence of several factors, including proximity to the ocean and the seaward orientation of the site, the presence of old Sitka Spruce trees with defoliated lower branches, and the presence of sites rich in nitrogen and calcium such as sea lion haulouts or seabird nesting sites.
Given its strong tendency to colonize small branches, the Seaside Centipede Lichen has a short lifespan. Over the course of 10 to 15 years, the small branches are typically taken over by mosses, hepatics and other lichens, all of which tend to displace the Seaside Centipede Lichen. Like all lichens, the Seaside Centipede Lichen is a plant organism composed of fungus and algae, which exist in a symbiotic relationship. This is a mutually beneficial relationship that is essential to their survival. While there are sexual fruiting structures near the tips of mature lobes, these structures are not involved in the lichen’s reproductive process. This species reproduces vegetatively by releasing soredia, which are powdery particles containing cells from both of the partners that make up this lichen. These soredia are essentially instant lichen plants that can establish themselves directly without having to recreate the plant’s characteristic symbiotic relationship. While the Seaside Centipede Lichen produces abundant soredia, they are confined to the inner surface of a few tiny structures at the tips of the lobes, which makes dispersal difficult. Forest birds may possibly help the Seaside Centipede Lichen to reproduce by carrying its soredia from tree to tree.
Logging operations constitute the main threat to the Seaside Centipede Lichen, due particularly to the enormous commercial value of its host, the Sitka Spruce. Other threats to this species include housing developments, such as the project that resulted in the disappearance of a population in the southern part of Ucluth Peninsula and, albeit to a lesser extent, the gathering of branches by campers for use as firewood. Seaside Centipede Lichen is very vulnerable to the increasingly harsh winter storm activity associated with global warming.
The Seaside Centipede Lichen is protected under the federal Species at Risk Act (SARA). More information about SARA, including how it protects individual species, is available in the Species at Risk Act: A Guide.
Half of the Canadian population of Seaside Centipede Lichen is in the Pacific Rim National Park Reserve where it is protected by the Canada National Parks Act.
Provincial and Territorial Protection
Status of Recovery Planning
Recovery Strategies :
Name Recovery Strategy for the Seaside Centipede Lichen (Heterodermia sitchensis) in Canada
Status Final posting on SAR registry
Seaside Centipede Lichen Recovery Team
Brian Reader - Chair/Contact - Parks Canada
Phone: 250-478-5131 Fax: 250-478-8415 Send Email
Recovery Progress and Activities
Summary of Progress to Date The Seaside Centipede was discovered in 1983 in Pacific Rim National Park Reserve. Prior to 2001, only two localities for this species were known. One of these sites was outside the Park Reserve, and was lost due to a housing development. Intensive field surveys are helping to determine the distribution of the lichen, as well as its habitat requirements. Summary of Research/Monitoring Activities Pacific Rim National Park Reserve was intensively surveyed for Seaside Centipede in 2001-2002. This study confirmed that the lichen has very particular habitat requirements, growing only on small slow-growing twigs of old Sitka Spruce trees near the ocean. Furthermore, the species requires exceptionally high levels of nutrient enrichment, particularly nitrogen. Two primary nitrogen sources are bird guano and sea lion scats (i.e., feces); Seaside Centipede typically grows below perching sites of birds or near sea lion winter haulouts. It is suspected that the high concentration of nitrogen in the air near sea lion haulouts permeates the bark of nearby trees. Surveys are also being conducted outside Pacific Rim National Park Reserve to establish the lichen’s entire range in British Columbia. In 2004, Seaside Centipede was found in Kyuquot Sound, 130 kilometres north of Pacific Rim, representing the northern-most observation. Samples of Sitka Spruce branches from Seaside Centipede communities are being analyzed chemically to further clarify the lichen’s pH and micronutrient requirements. Branches from other lichen communities are also being chemically analyzed for comparison. Summary of Recovery Activities Lichens are slow-growing and sensitive to disturbance. Furthermore, public use of Pacific Rim National Park Reserve is concentrated near the shore, which is also Seaside Centipede’s preferred locale. Therefore, park users are asked not to collect branches with lichen for firewood. Hikers of the West Coast Trail are encouraged to take care when hanging food from trees to keep it away from rodents and bears; using a tree branch that already has the lichen rubbed off it is preferable to disturbing lichen on another branch. Cooperation of the public will help to minimize direct impacts on Seaside Centipede and other rare lichens found in Pacific Rim National Park Reserve.
PLEASE NOTE: Not all COSEWIC reports are currently available on the SARA Public Registry. Most of the reports not yet available are status reports for species assessed by COSEWIC prior to May 2002. Other COSEWIC reports not yet available may include those species assessed as Extinct, Data Deficient or Not at Risk. In the meantime, they are available on request from the COSEWIC Secretariat.
10 record(s) found.
- COSEWIC Status Reports (1 record(s) found.)
- Response Statements (2 record(s) found.)
- Recovery Strategies (1 record(s) found.)
- Action Plans (1 record(s) found.)
- Critical Habitat Statements (1 record(s) found.)
- COSEWIC Annual Reports (2 record(s) found.)
- Consultation Documents (2 record(s) found.)
COSEWIC Status Reports
Response Statement - Seaside Centipede Lichen (2022-01-10)This leafy lichen is known from 20 occurrences on the west coast of Vancouver Island, Canada, and from two in the US. It has highly specific habitat requirements and grows only on partially defoliated small-diameter Sitka Spruce twigs on trees, close to the shoreline, that often receive nitrogen enrichment from sea lion haul-out sites or bird nest sites. The number of mature individuals (thalli) is thought to be less than 1000, and the lichen is highly vulnerable to intense storm activity associated with climate change that destroys the twigs upon which the lichen is found. The change of status from Endangered reflects increased knowledge of the distribution as a result of increased survey effort.
Response Statements - Seaside Centipede Lichen (2006-11-29)This is a foliose lichen restricted to shoreline Sitka Spruce trees on the west coast of Vancouver Island. It has been documented from only ten locations in Canada, 11 worldwide. It requires high levels of nitrogen, so is restricted to sites subject to nitrogen enrichment, for example, sea lion haul-out sites and bird nest sites. The species may have poor dispersal abilities. It is highly vulnerable to tsunamis, and intensified winter storm activity associated with global warming.
Critical Habitat Statements
COSEWIC Annual Reports
COSEWIC Annual Report - 2006 (2006-08-30)2006 Annual Report to the The Minister of the Environment and the Canadian Endangered Species Conservation Council (CESCC) from the Committee on the Status of Endangered Wildlife in Canada.
COSEWIC Annual Report 2020 to 2021 (2021-10-12)Over the past year COSEWIC assessed a total of 66 wildlife species, of which 4 were assigned a status of Not at Risk. Of these 66, COSEWIC re-examined the status of 41 wildlife species; of these, 80% were reassessed at the same or lower level of risk. To date and with the submission of this report, COSEWIC’s assessments now include 826 wildlife species in various risk categories including 369 Endangered, 196 Threatened, 239 Special Concern, and 22 Extirpated (i.e. no longer found in the wild in Canada). In addition, 19 wildlife species have been assessed as Extinct, 62 wildlife species have been designated as Data Deficient, and 202 have been assessed as Not at Risk.