Global warming harming plant-eating animals in the Arctic
Global warming harming plant-eating animals in the Arctic
mongabay.com
May 21, 2008
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Climate change is making it more difficult for plant-eating animals in highly seasonal environments like as the Arctic to locate food, according to a new study published in the online edition of the journal Proceedings of the Royal Society B.
Examining the feeding habits of caribou in West Greenland, researchers led by Penn State Associate Professor of Biology Eric Post found that the animals are “arriving at their breeding grounds too late in the season to enjoy the peak availability of food” and “suffering from a reduced ability to locate the few high-quality plants that remain”.
“This combination of time and space constraints is a double-whammy for species in highly seasonal environments,” said Post. “Moving through space–across the landscape–is a strategy used by these animals to deal with shifts in the time their forage plants are available, but now climate change is really putting this strategy to the test.”
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“Think of it like this,” he explained. “You’ve been out on the town with friends, and on the way home you want to stop off for a bite to eat, but the restaurant you’ve always gone to has closed early. So you try for one around the corner that’s always open a little longer. But when you get to that one, it too is closed. For herbivores, the fact that there are several ‘restaurants’–their food patches–dispersed across the landscape isn’t useful if they all begin closing at the same time in addition to closing earlier in the season.”
The researchers say that warming temperatures are causing the caribou’s primary food sources to emerge earlier in the year — before pregnant females reach their feeding grounds. Adding to their difficulties, high temperatures is reducing the variability of the landscape so that patches that patches of plants that in the past might have been late bloomers are now also emerging earlier.
“Variation in the landscape provides an insurance policy for animals, like caribou, that count on being able to climb to the top of the next hill or go across the next valley to find plants that are still newly emergent and highly nutritious,” Post said. “Climate change is reducing the value of that insurance policy.”