Now it’s the lemmings

Was the world really in equilibrium? So much biological research shows a unintended affection for point-in-time observation:

ScienceDaily: Will Lemmings Fall Off Climate Change Cliff?

Lemmings serve as an important prey species for a number of predators, including arctic foxes, red foxes, rough-legged hawks, peregrine falcons, snowy and short-eared owls, jaegers, gulls, weasels, wolverines, and grizzly bears. In fact, the population of many predators fluctuates in response to dips in lemming numbers. One of the key ingredients for lemming abundance and productivity is likely snow. Sufficient snow depth insulates the rodents from frigid temperatures, allowing them to devote more energy to breeding and less to avoiding predators. Later arrival of autumn snows, and earlier spring melts, could subject lemmings to longer periods of sub-freezing temperatures. Also, the tundra is experiencing unusual warm periods in winter, including freezing rain and episodes of thawing and freezing, which can coat much of the lemmings’ foods (sedges and dwarf shrubs) in ice.    (Has none of this occured before?)

Lemming predators also have to adapt to these changes. Predators that specialize on eating lemmings, such as snowy owls and arctic foxes, may suffer if lemmings are no longer so productive. Other predators may benefit. For example, there is evidence that red foxes have usurped considerable areas from arctic foxes in recent decades. Warmer temperatures may have increased the productivity of the red foxes’ diverse prey (ground squirrels, birds and lemmings), and improved their ability to survive the tundra winters. Researchers will investigate these possibilities, and track the productivity of foxes and raptors for comparison to historic data.

Arctic foxes, incidentally, may have other troubles than diminishing lemmings.