Liken the Lichens

By Valerie Fieldwebster


Fifteen thousand years ago after the Wisconsin Glacier receded, this area was left with bald rock. The melt waters from this enormous glacier inundated the area. The scouring action of this tumultuous water carved potholes, drilled tunnels and turned rock to sand and gravel.


It took thousands of years of evolving and revolving at 900 miles per hour for nature’s finely balanced cycles to allow succession to take hold and thousands more to make a visible difference. The naturalising of our landscape reads like a bizarre science fiction. All of our lush and complicated ecosystems began as rock, water, sunlight and some microscopic algae.


As the Glaciers retreated algae began to grow in the frigid water. Through photosynthesis the algae converted the sun’s energy into organic matter. Sadly, the algae had no structure and were therefore limited to living in the water. Then an ancient relationship blossomed, a relationship which provided the foundation for the next step in developing our ecosystem.


A shy, beguiling, limp alga met the fungi, and oh, what a body that fungi had. Each in awe of the other’s capabilities, they became one and called themselves lichen enmeshed in a symbiotic dance. Like the fungi, the lichen could grow on land, and like the algae, the lichen was also able to photosynthesize.


Lichens are a hardy bunch. They can grow in the cold arctic, on the wave-whipped rocks of Georgian Bay, or in a lush Muskoka forest. The lichens grew all over this fair land providing the foundations for the soil which supports us today.


Their foundation work done, lichens are now providing us with another function. They are now our ‘Canary in a coal mine’: Lichens don’t grow where the air is polluted. The Lichens declared Toronto inhabitable years ago.


Our natural ecosystem today is a great web of relationships. The greater diversity of species and the more relationships between species, the stronger and more resilient an ecosystem is. Lichens are just one small but important component of this complex system.



 Past articles are available in this blog under the Watershed Notes Articles category or under Past Articles in the Resources section.