Biologists burn mountains to rescue lizards

WASHINGTON U.-ST. LOUIS (US) — A 30-year study of collared lizards in the Ozark glades finds burning entire mountains and valleys has helped bring back lizard populations.

The work by Alan Templeton, a professor of biology at Washington University in St. Louis, is described in the cover story of the September issue of Ecology. The major revelation of the work: Landscape-level burning undid ecological damage that was slowed but not stopped by smaller prescribed burns.

In fact, it allowed the lizards to undertake their own expanded restoration effort without the assistance of worried biologists.

Odd as a lizard in the woods might seem, the collared lizard is just one of the larger and more visible of the many beautiful and rare species that live in the Ozarks. (Credit: Alan Templeton)


Burning also benefited other species, including a rare fen orchid and fen dragonfly, that were flying under the radar and would probably never have commanded labor-intensive restoration efforts on their own.

The glades are areas of exposed bedrock in the Ozark woodlands that create their own hot, dry, desert-like microclimates. Among the species that live in the Ozark glades are tarantulas, scorpions, prickly pear cactus—and lizards. The Ozarks also are home to more than 200 species found nowhere else on the planet.

The subject of Templeton’s research is the startling eastern collared lizard (Crotaphytus collaris collaris), so called for the darkly pigmented bands around its neck. The collared lizard is not endemic to the Ozarks, but its existence is entwined with that of many endemic species, as Templeton was to discover.

Witness to extinction

In 1982, after a rigorous survey of the Missouri glades, Templeton and colleagues estimated that at least 75 percent of the lizard populations had gone extinct. In some areas of the Ozarks, the lizards had vanished entirely.

What had happened? The answer turned out to be firefighting,

“In the Ozarks, you really didn’t have effective fire suppression until after World War II,” Templeton says. “That’s when all the fire towers and lookout towers went in, and the forest service began to fight wildfires.” (Smokey the Bear, the forest service’s mascot, dates from 1944.)

Glades no longer swept by fire were invaded by Eastern red cedar (Juniperus virginiana). “Before fire suppression, the red cedar was actually a very rare tree,” says Templeton. “Now they’re just all over the place.”

Templeton explains that red cedars typically grow slowly in the harsh glade environment. “So there is a 30- or 40-year lag before the consequences of fire suppression catch up to you.

“Then, suddenly, the red cedars are big enough to start shading out the glade and the whole glade community collapses.”

Glade restoration

At first, Templeton tried local restoration. People were hired to cut the red cedar and burn the glades.

“It didn’t take long to get the glades back into shape, at least from a botanical point of view,” he says.

Having restored the glades, Templeton wanted to restore the lizards. He reintroduced lizards to three glades on Stegall Mountain in the Peck Ranch in 1984, 1987, and 1989.

By 1993, however, it was clear that something was wrong. All three populations still existed but the lizards were not recolonizing other glades and no dispersal was taking place between the different populations.

As a population biologist, he knew that these small (often 10 or fewer), isolated lizard populations were not stable and would eventually hit a bump and crash again.

Power of fire

The problem, Templeton suspected, was that the lizards were trapped on the glades by the dense understory of the woodlands surrounding them, which had not been touched by fire for a long time.

In 1992, a Biodiversity Task Force, of which Templeton was a member, recommended landscape-level burning.

“We’d been burning prairies and glades for a long time, and everybody liked that,” Templeton says, “but what we were saying was we’re going to burn an entire landscape, including glades and prairies but also woodland and fens. Everything. Because that’s the way fires used to be.”

“We did the burn and to tell the truth, I wasn’t really very optimistic about it,” Templeton says. “I thought it was more really to reduce the fuel load, but I was stunned by what it did. Just one burn totally changed the environment. All of us were just shocked at how beneficial it was.

“The fire mainly got rid of the woody understory and thick mats of leaf litter, but it didn’t destroy the canopy trees. In fact, with the woody understory gone, the canopy trees grew better.

“The woody understory was mostly exotics, little shrubby trees that came from elsewhere. Once they were gone, the nutrients were released into the soil, and the soil was exposed to more sunlight, the endemics came back. All these endemic herbaceous plants came out of the forest floor and with them came a very abundant insect community.”

Templeton says soon the lizards started to move about. “The burn was in early April and by May and June of that year, the lizards were already beginning to disperse and colonize new glades.”

They burned larger and larger areas with similar results. The Ecology paper celebrates the fact that on Stegall Mountain, the first mountain to be recolonized, the metapopulation of lizards living on interconnected glades had been stable since 2000.

“The glades only support a dozen lizards or so,” Templeton says, “so you always have this problem that just by chance one population might go extinct. And if you’re in a situation where the glade can’t be recolonized, that’s it, you’re done.

“[T]he important point is we no longer have to transport lizards. Instead, we’ve created the ecological conditions that let them get there on their own four legs. I put them on three glades on those mountains, and on their own they’ve colonized another 140.

“So our work shows that if you manage at the landscape level and restore fundamental ecological processes, that’s the best way of doing species conservation, because we just don’t have the time and resources to save a species one by one.”

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