One of the most endangered lichens in the world is a canary in the coal mine for human-caused environmental impacts, according to a Nova Scotia scientist.
"So many activities that humans do on the landscape this thing is sensitive to. I think that the decline in the population over the last 10 years I think is really telling for us," said Robert Cameron, an ecologist with the Nova Scotia Department of Environment.
Cameron was one of the authors of a study published this week in the scientific journal Botany.
According to the study, the boreal felt lichen population is expected to decline by 49 per cent within 25 years, despite moves to prevent environmental damage from activities like forestry and air pollution.
There are only a few hundred boreal felt lichens left in Nova Scotia and it's protected under the federal Species at Risk Act.
It's also critically endangered internationally, and is listed as endangered by the Committee on the Status of Endangered Wildlife in Canada and critically endangered by the International Union for Conservation of Nature.
The species is incredibly sensitive to the fallout resulting from human activities, said Cameron, meaning its decline acts as an early indicator that something is wrong in the forest.
"We thought that once we brought in these special management practices, we'd see the population stabilize a bit, but we haven't seen that and so that's very surprising for us," said Cameron.
The study is a culmination of more than 10 years of research.
2 organisms working together
Lichens are somewhat odd because they're actually composed of two different organisms, working together in what's called a symbiotic association.
"The algae does the photosynthesis and the fungi kind of creates a nice environment for them," said Cameron.
The boreal felt lichen is a combination of a fungi and a cyanobacteria. Cyanobacteria can "fix" nitrogen out of the air, manipulating the nutrient into a form that the rest of the forest ecosystem can use.
Nitrogen is a highly important nutrient for forests but is often in short supply, especially in Nova Scotia forests.
This is part of what makes the lichen's surprising decline so worrying. It also acts as one of the first indicators that something is wrong with the surrounding environment, Cameron said.
"The research shows that the amount of acid rain that we're getting from those sources is beyond the capacity of the ecosystem to buffer," he said.
"So we know that acid rain is still having an impact on our ecosystems and the boreal felt lichen is just one species of many, but it's particularly sensitive so it's a good indicator species."
Much of Nova Scotia's acid rain is caused by pollution carried on prevailing westerly and southwesterly winds from the northeastern United States, the midwest and Ontario, said Cameron.
Rare boreal felt lichens not easy to find
Cameron said people looking to spot the rare lichen are probably out of luck.
"It would be very hard for people to see them. If you went to a forest on the Eastern Shore, a balsam fir forest, a coniferous forest close to the coast on the Eastern Shore, for example — that would be a good spot to look for it," he said.
They're also found in Richmond County, Cape Breton, as well in the humid and coastal region of Denali State Park in Alaska. They were once in Europe but have nearly disappeared except for one location in Norway.
Still found in Newfoundland
In Newfoundland, the boreal felt lichen thrives, with about 12,000 specimens.
"That trans-boundary pollution is not as big a problem for Newfoundland because they're a little bit farther west and a little bit farther north," said Cameron.
Unfortunately, Cameron said "we think it's been lost to New Brunswick altogether."
So what can be done to help protect the boreal felt lichens that are left?
Cameron said people in forestry can follow special management guidelines, such as buffer zones around the lichen habitat. Also, anything people can do to help reduce air pollution is a good thing.