Species Spotlight: Lichen

Rick Samco

Author: Scott Bowler  |  Published: March 13, 2023  | Category: Species Spotlight 

Oh man, I’m liking those lichen! Lichen are both ubiquitous and highly diverse, yet little known and understood, perhaps not really even noticed by many in “the general public.” Lichens are highly successful, and encrust somewhere around 8 percent of Earth’s terrestrial surface — an area greater than that covered by tropical rainforests.

With nearly infinite variations in color, shape, and form, lichen offer a fascinating topic for closer study.

Lichen are symbionts, coming from a “marriage” (or perhaps more properly, a fusing) of two or more distinctly different creatures. Most are composed of a tough fungal “shell” providing structure and protection to a colorful algae colony residing inside. The algae, through photosynthesis, provide nutrients to share with the fungus. Many lichens — probably all — also contain other life forms like bacteria, viruses, et cetera, making them far more complex than they first appear.

Lichen play a vital role in colonizing rock and other hard surfaces, beginning the slow process of soil creation. As scientist and author Merlin Sheldrake notes, in his phenomenal book about fungi, Entangled Life, “lichens are how the inanimate mineral mass within rocks is able to cross over into the metabolic cycles of the living … (they) are the go-betweens that inhabit the boundary of life and nonlife.”

Sheldrake also notes that the study of lichens was foundational to both the understanding of symbiosis and the development of the concept of ecology: “Lichens had become a type case of inter-kingdom collaboration.” This is because lichens are more than a fungal-plant partnership, and form in such a way that both partners create, what Sheldrake went on to describe as, an “emergent phenomena, entirely more than the sum of their parts … Lichens are small biospheres that include both photosynthetic and non-photosynthetic organisms, thus combining Earth’s main metabolic processes.”


Stewardship Fence Building Timelapse

Stewardship Fence Building Timelapse


What defines Oregon’s high desert?

What defines Oregon’s high desert?

Bounded by the Cascade Mountains to the west and the Blue Mountains to the north, Oregon’s high desert covers approximately 24,000 square miles. Annual rainfall in the high desert varies from 5 to 14 inches. The average elevation is 4,000 feet; at 9,733 feet, the summit of Steens Mountain is the highest point in Oregon’s high desert. The terrain of the high desert was mostly formed by a series of lava flows that occurred between 30 and 10 million years ago.

Sources: The Oregon Encyclopedia; Wikipedia  


Helen Harbin, ONDA Board Member

Helen Harbin, ONDA Board Member

“I connect with Oregon’s high desert through my feet, my eyes, my sense of smell, and all the things I hear. Getting out there is a whole body experience.” Supporting ONDA, Helen says, not only connects her with wild landscapes, but is also a good investment. “I felt like if I gave them $20, they might squeeze $23 out of it.”

Crustose and foliose lichen grown on basalt

Scott Bowler

Xanthoria sp. and other species grow on pyroclastic ash flow

Scott Bowler

Wolf lichen (Letharia vulpina)

Scott Bowler

In Oregon’s high desert, we have hundreds of species, remarkable in their diversity, abundance, durability and tenacity. While lichens as a group can grow on almost any surface (and in some especially harsh environments they actually grow into and even below the surface layer of rock, which affords them more protection), most individual species have a relatively narrow habitat preference. Which variety grows where depends upon growth substrate, exposure, temperature, moisture and sunlight levels. Recently a species was found in Great Basin National Park, Nevada, for example, that was previously only known to be a high Arctic and Antarctic species — so clearly there’s a lot yet to discover.

Most of our high desert lichens are of the “crustose” form — like it sounds, a crust growing, usually, on a rock surface. They are able to dry out almost completely, yet can revive nearly instantaneously to utilize a bit of dew, snowflake, or raindrop, and even a species adapted to pack rat urine. And, most of our high desert species grow incredibly slowly, such as our lovely chartreuse yellow species, Acarospora chlorophana, which inhabits primarily shady vertical rock faces and may grow only a few millimeters per century.

Look for lichen next time you’re out exploring and see how many different kinds you can find. They’re really quite fascinating and worthy of a deeper dive — and quite photogenic too.

While you’re looking closely at lichen, you might also notice the dark semi-shiny surface on many desert rocks that is known as “desert varnish.” This is also a biotic artifact, in this case a bacterial colony — but that’s another story for another day.

About the author: Scott Bowler is a retired science educator and frequent ONDA volunteer. Read more of his work.