High in Great Smoky Mountains National Park, a gentle rain soaks through a dense spruce-fir forest where the air goes quiet just steps from the road. On the moss-covered trunk of a single aging yellow birch, a careful eye can find more than 17 distinct species of lichen and moss — including at least one so rarely documented it has no common name.
Four people in rain gear move through it slowly, deliberately, magnifying lenses in hand. What looks like a quiet walk is something else entirely.
A park teeming with life most visitors never see
Great Smoky Mountains National Park draws millions of visitors each year, most following the same paved roads and popular overlooks. But the park exists at a different scale than most people experience — in the spongy mat of lichen on a birch trunk, in the microscopic rotifer drifting through a forest stream, in the red-cheeked salamander darting beneath a wet log.
The park is the most biodiverse site in the entire U.S. national park system. A global hotspot for salamanders, fungi, mosses, and lichens, it supports organisms that thrive across its varied elevations and countless microclimates. Since 1998, a long-running initiative called the All Taxa Biodiversity Inventory, or ATBI, has catalogued more than 22,000 species here — over 1,000 of them new to science at the time of discovery.
That number likely represents only a fraction of what actually lives in the park. Researchers estimate that documented species account for somewhere between a quarter and a third of its true biological diversity. The gap is widest for the smallest organisms: mites, mosses, rotifers, lichens. Rarely glamorous, but often foundational to the ecosystems around them.
The ‘Gang of Retirees’ filling the gaps science funding can’t
Academic field seasons tend to cluster in spring and summer, when weather cooperates and grant timelines align. The Smokies, however, do not pause between semesters. Species migrate, overwinter, and emerge during months when most researchers have returned to labs and classrooms.
That is where GRISLD comes in. The Gang of Retirees in Search of Life’s Diversity — not all of them retired, but all deeply committed — spends hours moving through remote corners of the park that professional researchers rarely reach. Connected through a listserv and a shared passion for the park’s biodiversity, they track species active in colder months and during migration windows that fall well outside the typical field calendar.
“The park’s really known during that time of the year,” said James Hollinger, a retired computer scientist turned amateur lichen scientist. “But what about the things that are off-period?”
The group works in partnership with Discover Life in America, the nonprofit that manages the ATBI alongside the park. During the 2025 government shutdown, when federal salaries were paused, nonprofit partners helped keep park operations running — a concrete illustration of how dependent the park’s scientific work has become on outside relationships.
Climate change is already rewriting the Smokies’ ecosystem
The changes are not subtle, at least not to those who have been watching long enough. Warming temperatures have allowed the woolly adelgid — a tiny insect native to Asia — to move into higher elevations and infest thousands of hemlocks. These trees, sometimes called the “redwood of the East,” once anchored stream corridors and shaded the cool, clear water that species like brook trout depend on. Many are now dead or dying.
Other invasive pests have devastated Fraser firs, elms, and ash trees. Each loss cascades through the food web. More frequent floods, fires, and violent storms are reshaping the landscape in ways visible even to casual visitors.
The most precarious situation belongs to the park’s high-elevation ecosystems. These “sky islands” — isolated pockets of cooler, wetter habitat — harbor species found nowhere else on earth. As temperatures rise, those species have nowhere to go. Some may disappear before anyone has formally recorded their existence.
Why naming a species is not a small thing
It might be easy to dismiss a lichen or a moss as background scenery. But these organisms do essential work. At high elevations, they regulate moisture, keeping the mountain cool and foggy, and their presence shapes the water cycle for entire downstream communities.
Retired biologist Paul Super, who coordinated research in the park for more than two decades, puts it plainly. “We’re at the top of the watershed,” he said, “and everybody’s drinking water is downhill from here.” The health of the smallest organisms on the mountain has direct consequences for the people living at its base.
Lichenologist Laura Boggess, who grew up in western North Carolina, describes documentation as something more than data collection. “The naming of a species, which isn’t a small thing,” she said, “is like an accumulation of small, cooperative creation.” As ecological change accelerates, that accumulation becomes more urgent, not less. Long-term observation also reveals what a single visit cannot: what looks normal today may represent decades of quiet loss. The visitor who comes for a week, as Super notes, will not know what the park used to be.
A race against time — and budget cuts
The ATBI is one of the oldest and most sustained biodiversity inventories in the country — a model that researchers studying ecological hotspots around the world have looked to for guidance. Its value lies in continuity. Short-term snapshots cannot reveal slow-moving change, and only decades of consistent observation can.
That continuity is now under pressure. Deep cuts to federal agencies threaten the long-term monitoring programs and biodiversity research the Park Service has historically supported. Nonprofits and volunteer networks are stepping in to fill widening gaps, but institutional infrastructure cannot be fully replaced by goodwill alone.
Will Kuhn, who leads scientific research at Discover Life in America, is direct about the stakes. Many species, he warns, could disappear before they are ever documented. The window for recording them is open — but it is closing.
There is something worth sitting with in that possibility. Every species that vanishes unnamed takes with it an unknown role in an ecosystem we are still trying to understand. The volunteers moving slowly through the rain, magnifying lenses in hand, are not just cataloguing the past. They are preserving the possibility that we might understand what we are losing before it is gone entirely.