Next time you’re out in nature, take a moment to look for the lichens. You’ll see their unique colors and patterns on the rocks, trees, and stone structures everywhere from Northern Minnesota to the world’s deserts, tropics, and tundras. A symbiotic organism that’s part fungi, part algae or cyanobacteria, lichens are the unsung pioneers of the natural world.
“They are really the first line of colonization,” says Daniel Stanton, a University of Minnesota ecologist, museum associate, and assistant professor in the department of Ecology, Evolution & Behavior. “They create the context for everything else to come in.”
Independent from roots or groundwater, lichens are tough as nails. They can grow and reproduce in extremely harsh, dry environments like Antarctica. Some studies have shown they can even survive in outer space. Around 10,000 years ago, lichens were among the first “settlers” when the last glaciers retreated in Minnesota. They established on the bare rocks, eroded those rocks and built up soil, and then seeds from other plants started to germinate.
A showy lady's slipper from the herbarium
Currently, there are about 170,000 lichens within the Bell Museum’s fungi collection. They come from across Minnesota, the broader United States, and all corners of the globe. “Most institutions have just a few thousand lichen specimens, so ours is one of the biggest and best collections available,” Stanton says.
Although bryophytes are considered plants and are from a different kingdom, they are similar to lichens in appearance and ecological niche. These mosses, liverworts, and hornworts also have a strong presence in the Bell’s collection.
The collection holds several bryophyte species that live on just a few islands in Greenland, northern Canada, and the Susie Islands of Lake Superior. In addition, there are many species of peat moss, or sphagnum. Abundant in peat bogs, sphagnum has been building up carbon since the glaciers retreated, so the specimens serve as invaluable climate records for the state.
During his time at the museum, Stanton has worked to identify and organize many specimens collected by Clifford Wetmore, a retired University of Minnesota biologist. Wetmore studied lichen diversity and lichens as indicators of air quality, with a focus on the genus Caloplaca, a relative of the golden splotches that adorn the rocky landscape of Minnesota’s north shore.
In recent years, Stanton began an extensive survey of lichens and bryophytes in Minnesota’s forests and the ecosystem services they provide. Mosses, for example, behave like a sponge: they absorb pollutants and change how water flows through the forest. The question is, how much benefit are they providing in Minnesota, compared to places like the Southwest, where they aren’t as abundant? “It’s a lot of exploratory work to try to answer these questions with hard numbers,” Stanton says.
Stanton could write a book about the important role of lichens and bryophytes, but his main advice to people is to simply pay attention: “What initially might look like a bare tree or a brown rock, when you look more closely, it may have more than a dozen different species on it. They are a big part of our Minnesota landscape that we often overlook.”
Housed in an herbarium on the St. Paul campus, the Bell’s lichens and bryophytes collection dates back to the 1800s. Each specimen is in a paper envelope with a label that identifies the collector, date, and location. Those envelopes are glued onto sheets and filed in folders.
In addition to tree bark, which the collector scrapes off, many of the lichen specimens are originally found on rocks. In these cases, the collector needs to chisel off the lichen so it doesn’t fall apart.
Needless to say, this provides some unique travel challenges. Stanton recently returned from a week in Mexico with a 30-pound bag of rocks. “I go around doing research with a hammer and a chisel, so I often look more like a geologist than an ecologist.”