The Milton Ranch north of Roundup was crawling with botanists on the cool, wet, third week in September, and Roger Rosentreter, retired state botanist for the Bureau of Land Management in Idaho, was probably the most ebullient member of the team.
When he arrived back at the ranch headquarters two hours past the usual afternoon gathering time, he said, “We’ve been out searching for manna lichens! Do you know what they are? They’re the kind that blow on the wind, and came in time to save the Israelites from starving in the desert during their exodus from Egypt!”
Bill and Dana Milton hosted and fed the high-powered group that was assembled by Andrea Pipp, the program botanist for the Montana Natural Heritage Program in Helena. Pipp applied for and received grants from the BLM and the Montana Native Plant Society to fund the team’s travel expenses, while they donated their time and expertise to compile the first inventory of lichens and mosses in Musselshell County.
Specimens of each moss and lichen species found on the ranch will be curated and housed at the University of Montana herbarium in Missoula, observation data will be entered into the MTNHP database, and as time allows, photographs will be posted on the MTNHP website.
Ten botanists who specialize in the study of lichens (lichenology) and mosses (bryology) spent at least four hours a day on their hands and knees, looking through magnifying lenses to locate the sometimes tiny organisms that live on the surface of soil, rocks, fence posts and bark. Each specimen was carefully placed in an envelope labeled with the exact location, habitat, general abundance, date and any other pertinent information.
Afternoons and evenings were spent identifying the specimens by species using microscopes, literature and shared expertise. Mosses are small members of the true plant kingdom while lichens are lumped in with the fungi kingdom. Despite this classification, lichens actually occupy two kingdoms, growing from a symbiotic relationship between fungi and photosynthetic partners of algae and/or cyanobacteria.
The lichen species was first identified in Saskatchewan, Canada, and later was thought to be widely present in the high plains of the continent. However, DNA testing has shown that there are actually five different species of lichen that resemble that first find.
McCune is confident that his sample in hand is the “real deal,” but genetic testing may be necessary to confirm that. He was also excited at the discovery on the ranch of a possible new lichen species that he and a colleague first found in Kansas and Minnesota. If it is verified to be a new species, they will be granted the honor of naming it.
Microscopic examination of a “cute” specimen collected by Daphne Stone, who is a consultant, adjunct professor in Oregon and president of Northwest Lichenologists, showed tiny dark circles on the surface of the lichen. These, she said, were the openings of perithecia, little pouches that contain fungal spores and algal cells which when released by water or wind can start a new lichen, assuming they come to rest in a suitable place to grow.
Neither can survive on their own for very long. To confuse the issue, some other types of green algae and cyanobacteria can also grow independently without a fungus partner. The team found many examples of free-living cyanobacteria on the ranch. Some looked like globs of jelly on the soil while others grew in long, stringy fibers embedded in the soil, serving as “glue” to hold soil particles together against the forces of wind and water erosion.
Green algae and cyanobacteria both photosynthesize, but it is the cyanobacteria that also fix atmospheric nitrogen. When it rains, the fixed nitrogen is leached from cyanobacteria into the soil, where it can be accessed by neighboring plants to promote growth.
Research by Rosentreter and others has shown that biological soil crusts made up of lichens, mosses, free-living green algae, cyanobacteria, fungi and liverworts (small green plants that may look like moss) play an important role in the health of our arid Western landscapes.
Where precipitation is intermittent and light, biological soil crusts help condition soils to absorb and retain moisture and nutrients. Lichens and mosses provide raindrop-capturing texture to the soil that lies between larger plants, and this reduces erosion and retains moisture at the surface.
Disturbed biological soils crusts are slow to re-establish because of these organisms’ limitations in reproduction and growth. It often takes 10 or more years for them to reach a beneficial density. In the meantime, invasive plants such as noxious weeds find the bare earth attractive for colonization. Wind and water erosion strip soil from the area until recovery is complete.
The team—which came together through Northwest Lichenologists, an organization that supports lichenology and bryology—collected hundreds of samples, and traded them around like baseball cards to get them properly identified.
For Rosentreter, McCune and Ann DeBolt,a retired BLM botanist from Boise, Idaho, interest in lichens began when Mason Hale, a renowned lichenologist working at the Smithsonian Institution in Washington, D.C., was invited to teach a class in the esoteric science of lichenology at the University of Montana’s Yellow Bay Research Station on Flathead Lake in 1977.
In 1981 he returned to teach the class again. That was the total extent of classes in lichenology ever taught at the University of Montana. Since then these three attendees have collaborated in many lichen projects, and they brought that sense of special camaraderie to the Milton Ranch.
Despite the wealth of expertise present at the ranch, the scientists admitted that there is much more to learn about the roles lichens and mosses play in rangeland health. It’s difficult to study organisms that are all so small and that shrivel when dry, yet still function and reproduce in mysterious ways to help hold the West’s precious soil in place.
Wendy Beye is a freelance writer living near Roundup. Her opinion pieces have appeared in High Country News out of Paonia, Colo., and as syndicated columns in other regional newspapers.