They blow like green scarves from trees, crust rocks, frost fences, paint bark, and glow on roofs, tombstones, blue tarps — really anything that will stay still for a bit can be a swell home for a lichen.
Lichens delight, confound and inspire. A thing unto themselves on the tree of life, they have puzzled scientists for more than a century as to just what they even are. One of earth’s most adaptable forms of life, lichens live on every continent and have passed multiple tests of their ability to survive in outer space, even for months.
Beyond their persistence, lichens are productive: They bind and build soil. Work as bioindicators of air pollution and climate change. Produce nitrogen from thin air that feeds the forest floor and wildlife. Hummingbirds and bushtits gather lichens to wind into their nests. Ungulates, including caribou, elk and deer, subsist on lichens in winter, when other foods are scarce.
Lichens provide dyes, food and medicines for people, too, with their antimicrobial, antifungal and immune-support attributes deployed in traditional herbal medicines. Extracts of lichens also are used in deodorant, toothpaste, salves, extracts, teas and perfume.
Self-sufficient, lichens have no roots, no vascular tissue, make their own food and don’t need pollinators to reproduce.
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Quiet and immobile as they may seem, they are actually articulate storytellers. The presence — or absence — of a lichen species, and changes in either, can indicate a shift in air quality and narrate the march of climate change.
And for all their fixedness — lichens are remarkably slow-growing — they are not passive. Some lichens wage mighty battles to define their boundaries, deploying chemical warfare, visible in a black line around their borders, to keep other lichens or their mortal enemy, moss, from encroaching, and even growing right on top of them, snuffing them out.
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It was Spribille who revealed that lichens are not a twosome at all, but actually a ménage à trois, with a hitherto overlooked partner — for some 140 years.
Spribille and his collaborators shared their discovery in a 2016 scientific paper published in Science. Their genetic analysis found that lichens aren’t just the result of a single fungus and a photosynthesizing partner (be it an alga, a cyanobacteria, or both.) They found there also is a second fungus, a yeast, in the mix. Follow-up DNA analysis by Spribille and his colleagues — of 52 lichen genera from six continents — also detected the second fungus. The initial breakout from the one-lichen-one fungus paradigm was not a one-off.
Scientists are still exploring whether the yeast is truly a symbiotic contributor, or just along for the ride. But even discovering its presence was a shocker, revealing lichens to be ecosystems unto themselves, with complexities that scientists are still trying to understand.
“We underestimated lichens for a very long time,” Spribille tells me. “It is not so much that people in the past got it wrong, as that they were missing a part of the picture, with the tools they had available to them, before the advent of genomics and modern molecular DNA sequencing.”
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“Why wouldn’t they matter?” Goward says of lichens. “There are animals that feed on them, reindeer and caribou would not exist without them, they are beautiful, they color our world, they grow where other things don’t grow, they can live where nothing else can, they have the capacity to grow everywhere.”
And they are that example in nature in which one plus one equals … three. Perhaps that is why lichens have challenged science for so long.
“Science is reductionist,” Goward said. “The study of biology reduces life to its parts, the whole disappears. Lichens challenge that.”
To him, though, it goes much deeper. Lichens provide a window to see how in life things really work.
“It is still gobsmacking, the idea that lichens are a portal through which you look in one direction, and what you look at is the organism, and you turn around and what you see is the ecosystem, and they are a variation on the same thing.”
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The way forward to a better future is an empathic relationship with the living world, Goward says, a future in which we recognize and honor our connections to the earth, and one another. Lichens, he continues, are our ancient mentors in this, reliable truth tellers about how the world really works.
“You can see the whole world in lichens.”
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