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More than meets the eye.

At first glance, the rock gnome lichen may not look like much--a mere crusty, green growth, easily overlooked in the dramatic landscapes where it occurs. But this Plain Jane combination of fungi and algae actually boasts ancient origins and exotic family ties--and for more than a decade, scientists have puzzled over the causes of its decline and what the lichen's disappearance would mean for the national parks and the broader ecosystems where it's found.

A member of the reindeer moss family, the rock gnome is the only species in its genus to grow in North America. Its closest relatives live in the Himalayas and the highest mountains of eastern Asia, including Japan. Like other lichens, the rock gnome is thought to be among Earth's first colonizers, clinging to rock surfaces and dissolving nutrients in the soil, allowing other plants like mosses to move in.

Scattered along high, rocky peaks and moist, deep river gorges throughout the Southeast, including the Blue Ridge Parkway and Great Smoky Mountains National Park, the rock gnome lichen was federally listed as endangered in January 1995. At the time, 32 populations were known to exist in the country--only seven covering areas larger than two square meters. Most covered about a yard or less. Since then, the total number of populations has risen to 49.

Evidence shows that certain human activities continue to affect the species' status. Hikers, rock climbers, and sightseers flock to Appalachian summits for grand scenic views and athletic thrills, unaware of the rare and delicate plant life under foot. "There are places in the Blue Ridge Parkway where you can see footsteps where people have walked [on the lichen]," says Chris Ulrey, a plant ecologist for the park. "No matter how well we 'sign' a place--whether we use interpretive signs or more law enforcement types people continue to go into these closed areas. If people really want to help, they should stay on trails and help us police these areas."

An elusive battle exists between illegal collectors and park staff stretched thin, unable to monitor remote areas where the plant occurs. Poached rock gnome lichen has a zero life expectancy, but collectors infatuated with owning a rare species harvest dwindling populations anyway.

Invasive species and dangerously high acidity from air pollution may play a role in population decline as well. The balsam and hemlock wooly adelgids destroy Frasier firs and hemlocks that play vital roles in balancing ecosystems where the rock gnome exists. Streambeds with dwindling hemlock populations lose shade, causing a change in air moisture. Because of the lichens demand for a precise amount of light and moisture, it cannot adapt quickly enough to such abrupt habitat changes.

But perhaps most perplexing to scientists is the potential effect of air quality on the lichen. Former U.S. Fish and Wildlife Service (FWS) biologist Nora Murdock, now a National Park Service (NPS) ecologist, worked side-by-side with Yuri Martin, a lichenologist from Estonia who travels the globe using lichens to monitor air pollution. As part of the FWS endangered species program, they performed intensive sampling from rock gnome lichen tissue throughout its southeastern range. Although end results showed no direct link between air pollution and the rock gnome, Murdock says that does not mean there isn't one, because "air pollution is a good guess for any declining plant."

A majority of rock gnome populations exist at high altitudes, relying on the moisture from clouds. These clouds may contain large amounts of contaminants produced by nearby coal-burning power plants and vehicular traffic. According to the Park Service, local rainfall in the Great Smoky Mountains is five to ten times more acidic than normal rain, and clouds covering the mountaintops are often 100 times more acidic, resulting in increased damage to vegetation at higher elevations. "It would probably be foolish to assume that air quality does not have an effect on the lichen, but it's a hard thing to prove," Ulrey says, mostly because such monitoring is costly and not an option with current park budgets. "Funding is always an issue with us. People should write to their politicians to boost funding for rare species monitoring and recovery."

Until funding is increased, he says, the best park rangers and others can do is to protect known populations from visitor threats and strive to obtain the quantitative data they're currently lacking. Within the parks, Ulrey adds, populations appear to be stable--but as air quality declines, the rock gnome lichen may decline with it.

"For the majority of people in this country, their day-to-day lives certainly wouldn't be impacted if the rock gnome lichen disappeared," Murdock says. "But it's one more brick out of the foundation of the building, and we don't know enough about what it's connected to and what it's holding up. Maybe you can get away with pulling one brick out--but then you take another, and another, and at some point you take the final one. The more you look into the connections, the more you realize how complex everything is, how little we know, and how desperately dangerous it is to let these species slip away from us."

Amy M. Leinbach is assistant editor for National Parks magazine.
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Title Annotation:Rare And Endangered; rock gnome lichen
Author:Leinbach, Amy M.
Publication:National Parks
Geographic Code:9JAPA
Date:Jan 1, 2005
Words:864
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