BACK OFF: A mother marmot with her pups makes an alarm call.© BEN HULSE
This spring, ecologist Dan Blumstein’s research team headed out to field sites in Colorado to study yellow-bellied marmots (Marmota flaviventris), large mountain rodents related to ground squirrels. The team’s observations will help determine how the animals are responding to a major population crash that occurred in 2011. “This year there was not a lot of snowpack, and that acts as insulation for animals underground,” says Blumstein, a professor at the University of California, Los Angeles. “It’s always, ‘Are there going to be any animals?’”
The precipitous drop in marmot numbers came as a bit of a surprise. For 40 years, marmot populations in the Upper East River Valley of Colorado had fluctuated—from 100 animals, to 60, to 30, and back up again. But during the decade preceding the crash, a decade of shorter-than-average winters, the marmot population had surged. “It tripled in size and got up to 300 animals. We were sort of overrun with marmots,” says Blumstein. Then, after an unusually long winter in 2011, the population plummeted. Blumstein says the marmot study highlights the value of long-term data sets spanning decades. “Had we quit after the first 40 years, we would have had a different perspective on what’s possible,” he says.
“Long-term data sets create a certain ...
