Squirrels and scopes in the line of fire
The Mount Graham red squirrel suffers an ecological shock
TUCSON, Arizona — During the 1980s and 1990s, environmentalists and American Indians tried just about everything, including lawsuits and chaining themselves to cattle guards, to stop the University of Arizona from building a telescope complex atop Mount Graham (HCN, 7/24/95: Making a mountain into a starbase: The long, bitter battle over Mount Graham). Environmentalists predicted the road-building and forest-clearing needed for the three telescopes would sound the death knell for the Mount Graham red squirrel, an endangered species found only atop southern Arizona’s tallest mountain range.
Construction on the telescopes began in 1989, with the agreement that they would only impact 8.6 acres of the mountaintop — and the squirrel survived.
But this summer, lightning-sparked wildfires nearly destroyed both the squirrels and the scopes. According to environmentalists, the crisis also let firefighters complete a controversial forest-thinning project on one of the Southwest’s most heavily litigated patches of land.
The Mount Graham red squirrel has been isolated on this mountaintop for thousands of years. In the cooler, wetter period before the end of the last Ice Age — when piñon and juniper grew in Tucson instead of saguaros and cholla cacti — the squirrels found suitable habitat in the region’s lower mountains. But as the Southwest warmed and dried, the squirrels and the forests they depend on retreated upslope, disappearing from all but the highest terrain.
Because of the squirrel’s vulnerability, public access to nearly 2,000 acres around the observatories — which the government declared a refugium for squirrels in 1988 — is forbidden. Despite that, the university had won approval over the past two years to clear about 850 trees 100 feet out from the telescopes to reduce fire danger. This year, it proposed extending that work another 100 feet, asking the Coronado National Forest to approve the project with only a limited environmental study.
That proposal was still under review when the 29,400-acre Nuttall and Gibson blazes converged in early July to become crown fires as they hit the mountaintop’s old-growth spruce-fir forest. With flames approaching the telescopes, firefighters removed 1,000 to 1,500 trees from the area, clearing even more fuel than astronomers had proposed.
Had the trees not been removed, says Jack Cohen of the Forest Service’s Missoula Fire Sciences Laboratory, the inferno would have come within 50 feet of the $110 million Large Binocular Telescope.
But Robin Silver of the Center for Biological Diversity says the university took advantage of the fire to expand its footprint. "They’ve sterilized an area that’s now a 200-foot radius around what was supposed to be their 8.6-acre limitation," says Silver.
The fire did scorch the heart of critical habitat for the squirrel, and the ecological shock hit a population already in grave condition. Just 284 squirrels were found in this spring’s survey — half the peak recorded in 1999.
Before the fires, biologists were hopeful the overall squirrel population would rise because of a bumper crop of the cones squirrels eat. Nine out of 10 females produced litters this spring, potentially adding 400 young squirrels, says John Koprowski, head of the University of Arizona’s squirrel monitoring project.
Now, however, newborn squirrels that escaped the flames will struggle to make it through the winter because cones, mushrooms and other food sources are gone. Many middens — piles of debris where squirrels squirrel away their food — also burned.
"It certainly burned incredibly hot up top," says Koprowski. "We’re probably talking a century before you have real habitat up there." But there is still hope: "Things could have been much worse," he says. "The burn wasn’t as severe as many feared, and it was controlled before it hit some of the best areas of squirrel habitat."