Tucson Region

Fire may devastate imperiled squirrels

Scientists fear the Nuttall Complex fire may devastate the sole population of Mount Graham red squirrels, an endangered species already imperiled by insect outbreaks, habitat loss and long-term drought. "It's what all of us connected to the biology end of this have feared," said John Koprowski, head of the UA's red squirrel monitoring project. The squirrels are restricted to about 10,000 acres above 8,000 feet elevation in the Pinalenos. Some of their best habitat lies between the fire and the Swift Trail, which firefighters plan to use as a fuel break. South-facing slopes that may be spared tend to have the most squirrels, Koprowski said, but the fire appears to be charring bug-killed forests that squirrels were just starting to recolonize. "We probably have 80 to 90 percent of females nursing their litter right now and at the stage where the little guys are just starting to emerge," he said. "They're probably not very well equipped to deal with this." The relatively agile adult squirrels are likely to flee the flames, but the fires may destroy the trees they rely on for cones to eat and the food caches squirrels fiercely defend. "It's not, in one fell swoop, going to wipe out every last squirrel. It's the loss of so much habitat that really creates the problem," he said. There are roughly 300 squirrels in the Pinalenos, about half the level recorded in 1999, before drought and insect outbreaks devastated Mount Graham's upper reaches. In 1997, the UA's monitoring project found 72 squirrels in the spruce-fir forest; by 2001, the number was down to eight. Even under the best conditions, it may take hundreds of years for the 2,000-acre spruce-fir forest to come back, but some scientists believe climate change may make that harder. "The spruce-fir may never come back because it's so dry," said Thetis Gamberg, a wildlife biologist with the U.S. Fish and Wildlife Service. "Nothing will ever be what it was before." A hint of fire's danger to the squirrels came in April 1996 during the 6,716-acre Clark Peak Fire. The Forest Service estimated 27 squirrels died in the fire or through its suppression.