One man’s moss helps study air quality

by David Hyland

While most visitors to the country’s national parks gaze up at nature’s majestic beauty, Clifford Wetmore stares at the ground. For the University plant biology professor, the majesty is in the lichen that he finds sprinkled across landscapes.
For most of his 40-year career, Wetmore has collected more than 80,000 lichen samples from national parks to study. In recent years, he and others have used the lichens to monitor the levels of air pollution.
Lichens are symbiotic, non-vascular organisms, similar to fungi or moss. There are more than 20,000 types of lichens throughout the world, with 550 types in Minnesota alone.
The value for air quality studies stems from lichen’s sensitivity to changes in the air’s composition, Wetmore said. Lichens are very reactive to the presence of sulfur dioxide in the air, which is a by-product released from smoke stacks.
Within a 50-mile radius of smoke stacks, some species of lichen die due to the poor air quality. Through studies of the plant, pollution control officials can determine if the air is worsening in those areas.
In conjunction with various government agencies, Wetmore has traveled to several national parks to conduct air surveys.
“There are still many places in this country where there are very few lichens because of air quality problems from the past,” said Jim Bennett, a research ecologist with the United States Geological Survey.
For the air quality tests, Wetmore combs the park for as many lichen samples he can find. He takes them back to his lab where he spends six to nine months identifying and conducting elemental analyses on them.
He said his air quality findings have typically received a mixed reaction by government officials.
“Mostly, the people who take it seriously are the people in the parks and in the forests,” he said. “The higher people in Washington, they don’t care much about it. They’re more interested in paper pushing.”
While it would be expensive for the government to start up a monitoring system of their own, Wetmore said, his work in the parks can be done cheaply.
Wetmore has studied in 30 national parks and wilderness areas throughout North America. Throughout his career, he has made trips to the Caribbean, China, and Australia, and he studied in Antarctica for three months.
Recently, Wetmore has been working on a lichen project in the Sonoran desert, which spreads across northern Mexico and California. With an international team, Wetmore and others have been cataloging, for the first time, what lichens are present there.
Besides their value for air quality studies, Wetmore said lichens are important as antibiotics and are a crucial food source for caribou and reindeer.
For Anita Cholewa, associate curator for the Bell Museum, Wetmore’s expertise is a rarity. She estimates that he is one of only a dozen in the country.
With fewer students interested in lichenology and scarce course offerings, the number of experts is shrinking, said Bennett, who is also an adjunct professor at the Institute for Environmental Studies at the University of Wisconsin-Madison.
“It seems to be a dying specialty,” Bennett said. “We’ll lose a lot of information if there aren’t anymore of them, if that ever happens.”
Cholewa has her own theory about the scarcity of lichenologists.
“Lichens aren’t showy like roses, tulips and lilies,” she said.
Although he is the only expert at the University, Bennett said Wetmore is far from isolated.
“He has contacts all over the world,” Bennett said. “He has an international reputation in his field as collaborated with many lichenologists around the world. In certain groups, he’s the expert.”
Cholewa said despite lichens’ obscurity and the lack of experts, lichens are important to study.
“If we want to understand how nature operates,” Cholewa said, “then its important to understand how all the facets work and how they work in connection to one another.”