Updated: Jul 10, 2020
by Lee Dickson, Nature Journal South Africa member
I don't know how many people give much thought to lichen - that flaky greenish-grey stuff that grows on trees and rocks and old buildings - but it has always fascinated me.
When we learned about it at school, we were told it is the first organism to grow in a new environment[i]. Imagine an undersea volcano erupting and pushing a new atoll up above the surface of the ocean. It starts as bare rock, and it is likely that the first thing that will grow there is lichen. As time passes, the lichen will help to weather the rock, which helps produce soil in which plants can grow. As time passes, more and more organisms, both plants and animals, will arrive; and that bare rock becomes a tropical paradise with a rich variety of vegetation, trees and flowers and other plants, where birds, insects and other animals now live. But it all starts with lichen.
Lichen comes in an amazing variety of forms, in all sorts of colours and shapes. It can grow almost anywhere on our planet (even inside rocks, apparently, not just on them!). Rocks covered in lichen can look like abstract works of art. The health of an ecosystem can be determined by the kinds of lichen that grow there; sometimes their presence will show how polluted an area is[ii].
Some years ago, I used to attend Stella Presbyterian Church in Glenmore, Durban. Stella was a small, but very vibrant church. It grew out of a Sunday school for children from the Kenneth Gardens flats in the back garden of the home of a member of Frere Road Presbyterian, which was slightly closer to town. In time, the children's parents started to attend, and the Sunday School grew into a church. Twenty-odd years later when I was going there, we'd sometimes have visitors to the church, who'd come in to see what it was like. From where I usually sat, near the entrance, I would often see these folk after a service looking slightly shell-shocked because so many members of the congregation would ask them:
"Oh, are you visiting?”
“It's so nice to see you!”
“Wouldn't you like to come and have some tea or coffee?"
And "We hope we'll see you next week, please come again".
On hearing that I attended this church, an acquaintance made a somewhat disparaging remark to me to the effect that because we were so few, we couldn't really be that effective as a church or we would surely have grown bigger. It stirred something in my storyteller's mind. One section of the pavement outside the church was full of rosettes of flat grey lichen, and some of them had joined up to form large solid patches. And I thought, "We're like the lichen. We're small and maybe don't cover much space on our own; but our small patches can grow together and form something that looks beautiful, or provide the substrate on which bigger things can grow."
And the best part of it? Lichen isn't a singular organism. It is a combination of algae or cyanobacteria and a fungus that have joined in a symbiotic relationship[iii]. The two very different types of organisms rely on each other for their existence and, in mathematical terms, provide a whole that is greater than the sum of its parts.
Nature Journaling Activities
1. Lichen Exploration BEETLES: Science and Teach for Field Instructors has a downloadable Student Activity Guide with full colour ID cards for 3 types of lichen: leafy, crusty and shrubby, plus field card for activity leader. They suggest studying algae and fungi before delving into lichen.
3. From “How to Teach Nature Journaling” by John Muir Laws and Emilie Lygren
I Notice, I Wonder, It Reminds Me Of
Zoom In: Zoom Out
My Secret Lichen (plant)
Collection or Field Guide
4. Observe, ask questions and record
Make a diagram and label the parts
How many kind of crusty, leafy or shrubby can you find? What is different about them? What is similar about them?
What is it growing on? Is something growing on it?
What patterns do you see?
Lichens Buffelskloof Eco Reserve blog
Lichens - Did You Know? Rogge Cloof Plantlife blog
First supplement to the lichen checklist of South Africa. Bothalia. 46(1) · May 2016 DOI: 10.4102/abc.v46i1.2065 Ahti, Teuvo & Mayrhofer, Helmut & Schultz, Matthias & Tehler, Anders & Fryday, Alan. (2016).
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[i] 2019 Update on the “long and widely held assumption that lichens occupied early terrestrial ecosystems prior to the evolution of vascular plants and drove global change during this time.” At the moment there is no evidence for this theory. ” No support for the emergence of lichens prior to the evolution of vascular plants” Matthew P. Nelsen, Robert Lücking, C. Kevin Boyce, H. Thorsten Lumbsch, Richard H. Ree [ii] “Lichens are the ’canaries in the coal mine’ of Nitrogen deposition. A shift in their species composition and/or their health exemplifies the potential beginning of ecosystem decline due to Nitrogen deposition.” https://www.nps.gov/articles/lichens-as-bioindicators.htm [iii] “The fungus provides shelter for the algae and the algae provides food for the fungi. Lichens do not have roots; instead they receive all their nutrients from the atmosphere.” https://www.nps.gov/articles/lichens-as-bioindicators.htm