GUIDE TO: Lichen Hunting

Worlds within worlds. Strange and wonderful, lichens push on the boundaries of our understanding of life and the questions we ask when studying nature. 

Lichens are those oddly beautiful, colourful, splotches you see everywhere ... once you start looking for them. Hiding in plain sight, you will find lichens spread like blistering paint on a tree bark and splashed like ink across rocks and walls. Walk along a city footpath, an exposed rocky coast, or in woodlands, and you will surely find lichens.

Lichens represent toughness, new beginnings and teamwork in nature. Best of all, they break the rules of our understanding of living organisms.

Here are a five starting points to feed your new lichen obsession.

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1. Lichens are ancient worlds and might be immortal.

Lichens are slow growing and can be extremely long-lived. Some lichens are considered to be among the oldest living things on earth. Lichens grow slowly, with some only adding around 0.5mm in diameter per year. And because lichens are rule breakers, researchers are currently probing the idea that lichen might even be immortal.


2.Lichens are ‘critical pioneers”.

Lichens are often the founding members of new habitats and among the first non-microscopic life forms to appear in a harsh new environment - think a concrete city footpath or an abandoned quarry. This is because lichens are incredibly resilient. They do not have roots, or require a constant supply of water. As a result, lichens can grow in places that other plants cannot.

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3. Lichen are micro-ecosystems, worlds within worlds. 

At first glance lichens look like quite like a plant or maybe a fungus. In fact, they are neither. And they are both. Lichens are ‘symbiotic organisms’. This means that lichens are a kind of alliance between a fungus and an alga, that benefit from living together. Lichen can survive harsh weather that would kill a fungus or an alga growing alone. The alga produces food through photosynthesis, while the fungus provides protective structures to gather moisture, nutrients and provide an anchor to the environment. Lichens are a character study in toughness derived from teamwork.

“What's also interesting about a lichen is realising that it's an entire habitat for other creatures inside it: of bacteria, of other fungi. So, when you look at a lichen, when you're walking by, it's not just an individual - it's an entire ecosystem, sort of like a tropical rainforest in miniature, just maybe the size of the palm of your hand growing on a fencepost. “ . Dr. Anne Pringle

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4. Lichens defy many classifications

Our inherited inclination is to study nature through tidy systems of classification. But, again and again, lichens break the rules. Lichens defy classifications and the instinct to shoehorn species into fixed buckets.

That said, for the beginner (like us), it is helpful to know that lichens generally fall into three three main groupings: 

1. fruticose (looks like a weird land-based seaweed) 

2. crustose lichens (circular paint-like splatters) 

3. foliose lichens (can look like blistering and peeling paint).

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5. Lichen remind us that we can only ask questions that we have the imagination for.

When the idea that lichen were ‘symbiotic organism’ was first proposed, it was scoffed at. The notion of different organisms living so closely with—or within—each other and that they should coexist to their mutual benefit went entirely against the dominant thinking of the time.  Researchers were wedded to the Darwinian idea of nature shaped by conflict, with winners and losers. The proposal that lichens were cohabiting, cooperative ‘symbiotic organisms’ was for decades dismissed. Simply because it didn't fit the dominant ideology. 

Further reading and information sources:

“We can only ask questions that we have imagination for.”

https://www.theatlantic.com/science/archive/2019/01/how-lichens-explain-and-re-explain-world/580681/

“I wanted to learn about fungi because those are the organisms that broke all the rules,”

https://www.nytimes.com/2013/01/01/science/studying-seemingly-immortal-lichens-in-a-place-for-the-dead.html










Gearoid Muldowney