Introduction to lichens

what are lichens?

Lichens are strange and ancient life forms.  Each one is a union between one or more fungi and either an alga or a bacterium, the whole quite different than the parts.

Some lichens are leafy as a head of lettuce, others a thin skim on bark or rock or soil. Some lichens can live and thrive in all sorts of conditions, but others require conditions that only the interiors of very old forests can provide.

Eons before forests existed, lichens, anchored to rocks, gathered dust and fragments, making soil. As trees grew in the new soil, lichens evolved with them, finding homes on trunks and twigs, in cracks and cavities. The older a forest, the more nooks and crannies it offers, and the more kinds of lichens find places to grow.

why are lichens important to forests?

Lichens play an important part in our forest ecosystems, providing food for moose and deer during harsh winters as well as supplying nest-building materials for flying squirrels and the migratory Northern parula.

Lichens can also tell us about the conditions in our forests. Because they feed by absorbing whatever lands on their surfaces, lichens are vulnerable to air pollution, some more than others. Thriving populations of these species indicate clean air. 

how can lichens protect Forests?

Some lichens are slow-growing, very particular in their choice of habitat, and vulnerable to any disturbance of that habitat.  Their presence is an indication that a particular forest has been relatively undisturbed for a long time. Such forests are likely to shelter other rare species and to be of high conservation value.  

Now that so many old forests have been destroyed, the lichens that depend on those complex, undisturbed habitats are endangered. Some have been listed federally and provincially as Species at Risk.  

In Nova Scotia the Department of Natural Resources and Renewables (NRR) is responsible "for the protection, designation and other relevant aspects of the conservation of species at risk in the Province, including habitat protection. Land use activities on crown and private lands have the potential to damage and destroy lichen populations and their habitat."  As part of its responsibility for protection NRR has developed Special Management Practices for Species At Risk Lichens. 

That is how one of the tiniest lichens has come to the defence of some of the biggest, oldest trees left in the Maritimes. 

Frosted Glass-whiskers lichen 

(Sclerophora peronella)

The Frosted Glass-whiskers lichen (Sclerophora peronella) is a tiny stubble lichen which needs to be examined under microscope to confirm its identity.  Here is what makes this lichen so special:

Fosted Glass-whiskers lichen. Photo: Ashlea Viola

other SPecies at Risk lichens in annapolis county

In addition to the Frosted Glass-whiskers lichen, citizen scientists have documented other species at risk lichens in forests around Goldsmith Lake and Beal's Brook.  These include examples of, Blue felt lichen (Pectenia plumbea), and Black foam lichen (Anzia colpodes), and Wrinkled shingle lichen (Pannaria lurida).


Blue felt lichen (Pectenia plumbea)

Photo: Nina Newington

Black foam lichen 

(Anzia colpodes)

Photo: Frances Anderson

Wrinkled shingle lichen (Pannaria lurida) 

Lichens are far from the only endangered species that need old forests. In Nova Scotia almost every species that depends on old forests, from the Blackburnian warbler to the American marten to the mighty Mainland moose, is in steep decline. The best way we can protect those species is to protect and restore the habitat they depend on: intact old forests.

The best way we can protect our own species is to change the way we relate to nature. 

We are a part of nature, never separate. 

What we do to the rest of nature we do to ourselves.