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Species at Risk

Seaside Centipede Lichen

Heterodermia sitchensis

What's the status of the seaside centipede lichen?

The seaside centipede lichen is listed as endangered under Canada's Species at Risk Act. This means that the species is very rare and at risk of extinction unless we ensure that its habitat is protected.

What's so special about the seaside centipede lichen?

Seaside centipede lichen research keeps revealing fascinating new information on this species' life history and ecology.

A Sitka spruce twig with seaside centipede lichen.
It appears that the seaside centipede lichen depends on nutrient enrichment to survive.
© Parks Canada

It appears that the seaside centipede lichen is dependent on nutrient enrichment from sources such as seabirds, raptors, sea lions and ancient First Nation village sites. At these sites, nutrient enrichment is provided by the rich organic materials in the sweepings and garbage that accumulated around the wood longhouses. People searching for such sites may even be able to use the lichens to indicate where the villages were. The seaside centipede lichen prefers, however, to get its nutrients from bird droppings and the constant, nutrient-rich spray of water in areas where sea lions gather. In fact, researchers were able to correctly predict the presence of seaside centipede lichen on an island based on this knowledge.

Species at Risk - Who Knew?

One colony of seaside centipede lichen has already been lost to subdivision development.

Why is the seaside centipede lichen in danger?

The seaside centipede lichen was originally discovered in Canada at two locations: one in Pacific Rim National Park Reserve and one adjacent to the park reserve. Unfortunately, the site outside the park reserve was lost to subdivision development.

The seaside centipede lichen only exists in a very small number of sites that provide the specific conditions necessary to its survival. This, combined with the species' poor capacity to spread, puts it at risk of extinction. In fact, in 1996, the entire known world population of the seaside centipede lichen was only 15 thalli (plant bodies)!

Seaside centipede lichen habitat.
Only a small number of sites provide the conditions necessary for the seaside centipede lichen's survival.
© Parks Canada

Although the lichen is protected in Pacific Rim National Park Reserve, it may be at risk from people gathering twigs and branches for campfires (which is illegal under the Canada National Parks Act). Coastline development is perhaps the greatest threat to any seaside centipede lichen that may exist outside of the park reserve.

The seaside centipede lichen can also be killed by salt spray, breakage of the host branch, wind, prolonged periods of dry weather, competition from other organisms (such as other lichens and mosses), and the loss of the lichen's source of nutrient enrichment.