Download seaside centipede - Draft

Seaside Centipede (Heterodermia sitchensis)
Global: G2G3 Provincial: S1 COSEWIC: E, BC List: Red
Note on Taxonomy for Heterodermia sitchensis: Lichen are composite organisms consisting of a fungus and a photosynthetic partner, usually an algae which
form a symbiotic relationship. Seaside centipede is a member of the family Physciaceae and is also referred to as Sitka shield lichen (E-Flora, USDA). Lichens
are generally assigned to one of four groups: Foliose Macrolichens (of which Heterodermia sitchensis belongs to), Mesolichens, Fruticose Lichens and
Crustose Lichens. These groups reflect the ecology and physical attributes of the species within each group (from “Ways of Enlichement” 2010).
Distribution: Elevation 0-200 m A unique lichen to North America, seaside centipede is known only from one remote area (Pacific Rim National Park) on the
west coast of Vancouver Island in BC and one site on the Oregon coast (Cape Lookout). Within its area of occurrence in BC nearly 70 percent of these lichen
are confined to the seaside forests of coves and inlets which range along the coastlines of the Mission Group Islands in Kyoquot Sound to Folger Island in
Barkley Sound (NRT, BCCDC 2007).
Description: This semi-erect arboreal lichen forms cushiony structures of irregularly branched lobes averaging 20 mm across. The stiff lobes are short to
slightly elongated, and quite thin (0.5-2 mm wide). The top surface is usually a faint greenish-white colour but can also have a deep blue appearance. The
smooth upper surface is strongly convex like a cup, with occasional warts and whitish spots. The lower surface has a white colour and cottony texture.
Reproductive formations shaped like small urns and minute wispy hair-like structures rim the upper edges or lip (NRT, BCCDC 2007)..
Look’s Like? The hair-like structures, urn-shaped outgrowths, pale greenish lobes and cottony lower surface all make this species structurally unique to other
lichesn which may be found in association with it. It may be confused with another Heterodermia species, elegant centipede however this species has distinctly
elongated lobes and lacks the urn-shaped outgrowths of seaside centipede.
Primary Habitat: This lichen has an extremely narrow range of habitat and nutrient requirements revolving around ventilation, humidity, substrate and
temperature. Ideal conditions appear restricted to localized micro-climates found on the lower branches of maritime variant Sitka spruce trees in association
with undisturbed old-growth western hemlock-dominated forests. All of which combine to restrict this species in its ability to colonize and reproduce
effectively.
Secondary Habitat: There is some indication that this species can survive desiccation and dryer exposed conditions, however its prolonged ability to tolerate
such changes to habitat and moisture regimes (i.e. changes due to climate change) is unknown (NRT, BCCDC 2007).
Critical Features: Within its narrow ecological niche, seaside centipede is only associated with small defoliated twigs in the lower canopy of Sitka spruce
within several meters of the high tide zone. This proximity to the marine environment is a critical factor as this lichen depends on very high moisture such as
that provided by sea-spray drift or fog. Protection from direct exposure may also be important (i.e. leeward sides of bays, coves and inlets). Nutrient sources
appear to be a key requirement. This species appears to be associated with locations where surrounding geology provides high mineral inputs (calcium rich
bedrock), marine and terrestrial inputs of fecal matter (below bird perches or high levels of seabird flyby, sea lion scat) as well as First Nations shellfish
midden sites (NRT, BCCDC 2007).
Seasonal Life Cycle
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Reproduction is asexual, lobes break off, disperse by wind or rain and colonize new Sitka
spruce branch substrates
*This lichen may live up to 10-15 years
Habitat Guild: Maritime variant mature and old growth coniferous forests
Threats:
 This species has a life history that suggests a strong dependence on local micro-climate factors and a need for habitat unlikely to go through any sudden
changes. A short lifespan, poor dispersal ability, highly specific habitat requirements, ephemeral nature of its preferred habitat and limited suitable habitat
 availability contribute to this species rarity and vulnerability to declines.
 Development, clearing, forestry and silviculture management practices, collection of branches for community purposes (e.g. firewood) and other
disturbance factors remain a significant issue.
 Recovery and recolonization rates for disturbed, damaged or destroyed colonies could take decades in order for suitable host tree maturation to occur.
 Clearing of forest understory and thinning and pruning of lower tree branches for recreational access or improvement of sightlines can involve loss of
lichen colonies and associated habitat potential.
 Forest harvesting within or in close proximity to seaside centipede colonies can reduce microclimate suitability and function and subsequent colony
viability. It has been suggested that a minimum buffer at least 60 meters wide is required to reduce harvesting impacts to sensitive lichens such as
Heterodermia sitchensis.
 Changes to the critical nutrient regimes this species requires to persist can lead to significant declines.
 Increased severity of weather events (precipitation, storm surges) and related impacts from climate change (potential loss of critical moisture regimes) are
difficult to project and manage for.
Key Conservation & Management Objectives
 A targeted inventory is needed to determine if undiscovered populations exist elsewhere within the Coast Region (i.e. Pacific Rim area) and to assess the
status of all known populations.
Draft 2010
Disclaimer: This species account and related conservation recommendations are draft only and presently under review and subject to change.
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Monitor existing populations on an ongoing basis to assess viability and reduce potential disturbance from land use activities. Where suitable habitat
occurs, work with land managers and land owners to ensure development or recreational activities do not disturb or encroach on sensitive areas.
Conduct outreach to raise awareness of this species and how to identify it to improve distribution knowledge
Prevent activities that will lead to changes to critical seaside centipede habitat requirements (kindling collection, clearing and slash removal) that will
reduce viability of existing populations.
Meet objectives for this species and the conservation of its habitat as set out in the “Recovery Strategy for Seaside Centipede Lichen (Heterodermia
sitchensis) in Canada”.
Sightings, specimens, or observations of activities threatening its habitat should be reported to the regional Species at Risk Biologist at the Ministry of
Environment office.
Main References/Literature Cited
National Recovery Team for Heterodermia sitchensis (Seaside Centipede Lichen). 2007. Recovery Strategy for Seaside Centipede Lichen (Heterodermia
sitchensis) in Canada. Species at Risk Act Recovery Series. Parks Canada Agency. Ottawa. vi + 19 pp.
Goward, Trevor. 2004. SEASIDE CENTIPEDE (HETERODERMIA SITCHENSIS): PORTRAIT OF A LICHEN. In the Botanical Electronic News, No. 335
September 29. Accessed online July 2010.
BC Species & Ecosystems Explorer (BC Conservation Data Center Summary Report)
Bjork, Curtis et al. 2010. Ways of Enlichenment: The Book (online). Accessed online July 2010.
International Forest Products Limited and BC Ministry of Environment. 2003. A Field Guide to Species at Risk in the Coast Forest Region of British Columbia
Develop With Care: Environmental Guidelines for Urban and Rural Land Development in British Columbia.
BC Species & Ecosystems Explorer (BC Conservation Data Center Summary Report)
NatureServe Explorer
Committee on the Status of Endangered Wildlife in Canada
E-Flora Electronic Atlas of the Plants of British Columbia
USDA, NRCS. 2010. The PLANTS Database
Image credits:
Seaside Centipede: Tim Wheeler
Habitat: Random Truth (Flickr)
Draft 2010
Disclaimer: This species account and related conservation recommendations are draft only and presently under review and subject to change.
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