Mosses are the underdogs of the plant world. These scientists are trying to protect them

From Harvest Public Media:

The forest at Shaw Nature Reserve outside St. Louis is a mosaic of dry browns on a cold January morning.

But John Brinda quickly homes in on a little patch of green and crunches through fallen leaves to get a closer look.

“I leave the trail as soon as I can,” Brinda said. “Trails are to get me near the bryophytes, and then I just run around in the woods.”

Brinda is an assistant scientist at the Missouri Botanical Garden who studies bryophytes — a group of plants that includes mosses, liverworts and hornworts. When he’s in the field, Brinda spends a lot of time on his knees, squinting at moss through a small magnifying hand lens he wears around his neck.

What Brinda and many bryologists have in common is an appreciation for the little guy. Mosses, they say, are underdogs.

“They’re overlooked,” Brinda said. “Not just in the conservation world; they’re overlooked generally.”

But that can be a problem. Mosses and other bryophytes don’t get much attention, even among scientists, so there are a lot of gaps in our understanding of them. It’s a conservation challenge — you can’t protect a species that you don’t know is struggling.

That’s why Brinda and a group of scientists from across Canada and the United States are launching a new group called the Bryophyte Conservation Alliance to better understand and protect these plants.

Ecosystem engineers

Mosses and the like play an outsized role in their natural communities, said Mandy Slate, a plant ecologist and assistant professor at The Ohio State University and a member of the Bryophyte Conservation Alliance organizational committee.

“It’s just like this missing link to understanding the entire ecosystem that we’ve just kind of overlooked,” Slate said.

The tiny plants affect how water moves through ecosystems, cycle nutrients like nitrogen and store carbon. That’s especially true of peatlands, which are moss-dominated ecosystems like fens and bogs.

“[Peatlands] are enormous carbon reserves — much more carbon is stored in peat than in trees, for example,” said Keir Wefferling, an assistant professor of biology at the University of Wisconsin-Green Bay who studies peatlands.

Bryophytes are also habitats themselves. Under a microscope, a patch of moss is like a mini forest, full of different types of plants and even smaller creatures, like tardigrades. And they’re indicator species, helping inform scientists about the integrity of a wetland or other habitat.

“They’re just wonderful,” Wefferling said. “They’re just beautiful, wonderful little plants.”

Many mosses can also come back to life after long periods of dormancy. In one example, scientists reanimated moss that had been covered in permafrost for hundreds of years.

“They started growing,” Slate said excitedly. “They had been covered in ice for hundreds and hundreds of years, and they were still able to grow. Like, that just kind of blows people’s minds.”

But she added there’s a lot left to learn about mosses and other bryophytes.

“We don’t know where they actually occur, we don’t know their abundance in those locations, and we don’t know any threats,” Slate said. “But all of that information is needed together at the same time to really understand how a species is doing.”

Federal protection

In order for a species to get legal protection under the Endangered Species Act, scientists need to first collect detailed information on it, including where it occurs and the threats it faces.

More than 1,600 species of plants and animals are currently protected under the act, but of those, only one moss is on the list. Brinda at the Missouri Botanical Garden said based on data from Europe, which is much further along in bryophyte conservation, North America may need to conserve as many as 500 species.

In the U.S., the only federally endangered moss is the South Llano Springs Moss, which only has one known population on a private ranch in Texas.

“To our knowledge, there’s only male individuals left in that population, and it is even possible that the entire population consists of clones of a single surviving individual, we really don’t know,” said Chris Best, a former Texas state botanist for the U.S. Fish and Wildlife Service who did the species assessment for the moss.

Best said in his 19 years at the Fish and Wildlife Service, he saw plants get a lot less conservation attention than animals.

“We have very few botanists in the whole country,” Best said. “And a lot of the work on plants done by our agency is done by people who had training in another field. You know, they really didn’t have botany or plant training, and that’s a concern to me.”

And mosses are an even smaller specialty within botany.

The South Llano Springs Moss was listed as an endangered species in 2023. Brinda at the Missouri Botanical Garden thinks if a larger plant had been facing the same conditions, it would have been protected decades ago.

“That’s the tip of the iceberg,” Brinda said. “There are a dozen other species that are in the same situation, but they haven’t had anybody advocate for them.”

As the Bryophyte Conservation Alliance gets to work, they’re cataloging where different species live. They’re also creating profiles for about 50 species that they know are in particularly dire straits, to collect the information that someone would need to petition the U.S. government for protection.

Appreciating mosses

While the Bryophyte Conservation Alliance would welcome more legal protections for mosses, liverworts and hornworts, the effort goes beyond federal lists.

“That would be awesome if the species that need it reach that point,” said Slate, at The Ohio State University. “But creating this network of people that are willing to share their expertise and opening themselves up to new people who don’t have that expertise but really care about their flora is another valuable outcome.”

Brinda’s work in St. Louis has taught him to look at the world in a new way, and he’s eager to share his knowledge and passion for mosses. He recommends beginners get a hand lens and a field guide to the bryophytes in their region to get started.

“You can go to pretty much any environment and there’s going to be some kind of bryophyte there,” Brinda said. “I mean, just walking down the street here, there’s things growing on the retaining walls, they’re in the alleys, they’re everywhere. But people just walk past them and don’t know their names and don’t know much about them. And I think they’re just really cool.”

This story was produced in partnership with Harvest Public Media, a collaboration of public media newsrooms in the Midwest and Great Plains, including Texas. It reports on food systems, agriculture and rural issues.