What is the Seaside Centipede Lichen?

The tiny Seaside Centipede Lichen lives only in the Pacific Northwest.
© Anna Roberts

This rare lichen of the Pacific Northwest was discovered only two decades ago, in the mid-1980's.

The Seaside Centipede Lichen is tiny-no bigger than a pencil eraser! The upper surface of each plant body (or "thalli") is usually pale greenish-white, but sometimes bluish-black. The lower surface is white and cottony. Urn-shaped outgrowths and tiny hair-like structures are two of the species' distinguishing features.

Where does the Seaside Centipede Lichen live?

A map of seaside centipede lichen locations in Canada
Much of the Seaside Centipede Lichen's range in Canada falls within Pacific Rim National Park Reserve.

As its name suggests, the Seaside Centipede Lichen is found where the land meets the sea. Just any old seaside won't do, however. The lichen needs just the right conditions to survive-continuous high humidity, good air circulation, moderate temperatures and shelter from exposure. These habitat requirements are so complex that the species lives only on the lower branches of Sitka spruce trees growing adjacent to the high tide line.

The known distribution of seaside centipede lichen is on the west coast of Vancouver Island. The core of its distribution is in and around Pacific Rim National Park Reserve of Canada. In 2004 the seaside centipede lichen was found 130 kilometres to the northwest of the park in Kyuquot Sound. There are also Seaside Centipede Lichen at one site in Oregon in the United States.

What's the status of the Seaside Centipede Lichen?

A Sitka spruce twig with seaside centipede lichen
It appears that the Seaside Centipede Lichen depends on nutrient enrichment to survive.

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.

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.

One colony of Seaside Centipede Lichen has already been lost to subdivision development.

Why is the Seaside Centipede Lichen in danger?

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

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)!

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.

What is Parks Canada doing to help save the seaside centipede lichen?

There are very few known sites where the Seaside Centipede Lichen grows. But these rare sites are home to most of the world's population of this species.

Recovery actions

Parks Canada is leading the development of a recovery strategy for the Seaside Centipede Lichen. The Seaside Centipede Lichen Recovery Team is reviewing a draft recovery plan that calls for further research, habitat protection and public education to help this endangered species recover.


Seaside centipede lichen habitat
Parks Canada is taking part in surveys of the seaside centipede lichen and research into its life history and ecology.

In 2001 and 2002, surveys and research were conducted in and around Pacific Rim National Park Reserve for Seaside Centipede Lichen. In total, 159 thalli were found. In 2003, Haida Gwaii and Gwaii Haanas National Park Reserve were searched for seaside centipede lichen. Although many new and rare species of lichen were found, researchers concluded that the Seaside Centipede Lichen likely does not occur in the archipelago. In 2004, a search was conducted for Seaside Centipede Lichen and other rare lichens in Kyuquot Sound and the Broughton Archipelago. New occurrences of Seaside Centipede Lichen were found on and around Spring island in Kyuquot Sound, bringing the total known number of thalli to 213 and extending the range 130 km to the northwest.

Although this work has substantially increased the known world population of this endangered species, it also clearly indicates how specific this species' habitat requirements are. Most of the seaside centipede lichen population exists in only a few sites.

In addition to surveys of the lichen's distribution, Parks Canada is also involved in research into the nutrient requirements of the Seaside Centipede Lichen.

Public education

In its research and as a member of the Seaside Centipede Lichen Recovery Team, Parks Canada is working with a variety of partners, including lichenologists and the Government of British Columbia.

How can I help?

Realize that everything is interconnected, that even the smallest part of an ecosystem has a part to play. A principle of the local Nuu-chah-nulth First Nations is "Hishuk-ish ts'walk" or "everything is one and interconnected."

If you are visiting Pacific Rim National Park Reserve:

  • Do not collect branches for firewood.
  • Take care when hanging food in bear bags in trees along the West Coast Trail. Use tree branches that have been used before rather than risk disturbing lichen on another branch. Don't use spruce trees.

At home:

  • Reduce your contributions to global warming, since the seaside centipede lichen depends on a cool, moist, temperate climate.