Species Spotlight: Lichen

Rick Samco

voices

Durlin Hicock, Alice Elshoff Award winner

“Protecting public land is part of my spiritual being. It’s central to my identity to be in wilderness and to see it protected.” Durlin is proud to protect public lands for future generations, saying, “The highlight of my childhood was our family’s weekend outdoor trips. I look forward to my grandchildren having similar experiences outside in their lifetimes, and it wouldn’t be possible without ONDA.”

fact

Bobcat

Found only in North America, where it is the most common wildcat, the bobcat takes its common name from its stubby, or “bobbed,” tail. The cats range in length from two to four feet and weigh 14 to 29 pounds. Bobcats mainly hunt rabbits and hares, but they will also eat rodents, birds, bats, and even adult deer.

Latin name: Lynx rufus fasciatus

fact

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

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.