Chubbier Climate
Warming brings more, fatter marmots
Climate change is a good deal if you’re a marmot living on a mountainside in Colorado – so far, at least. Warmer temperatures are enabling the burrowing mammals to get fatter and have more babies, researchers report in today’s issue of Nature. The finding – drawn from a field study that’s run for nearly 50 years – offers another insight into how global warming is shuffling the ecological deck.
Kenneth Armitage, a professor emeritus of ecology and evolutionary biology at the University of Kansas in Lawrence, began counting and weighing Colorado’s Yellow-bellied marmots in 1962. “At the time we started, we had no idea that climate change was going to be a problem,” he says. But the long-term data became invaluable to researchers interested in understanding how warming temperatures are affecting wildlife.
In Colorado, it turns out that earlier snowmelts and longer growing seasons have been manna for marmots. They come out of hibernation earlier, have more time to feast on plants and, well, profusely procreate. Marmot population growth jumped from 0.56 marmots per year from 1976 to 2001, to 14.2 new marmots annually between 2001 and 2008, report a research team led by Arpat Ozgul of Imperial College London in the United Kingdom. Over the same period, your average adult marmot put on nearly a pound, jumping from 6.82 to 7.56 pounds.
The good times, however, may not last, Armitage warns. Over the long haul, for instance, reduced winter snow packs could mean less spring runoff – and so fewer plants that marmots like to eat. – David Malakoff
Source: Ozgul, A., Childs, D., Oli, M., Armitage, K., Blumstein, D., Olson, L., Tuljapurkar, S., & Coulson, T. (2010). Coupled dynamics of body mass and population growth in response to environmental change. Nature, DOI: 10.1038/nature09210
Image Ben Hulsey/Nature
