Global warming’s refugees
EAGLE COUNTY – Meet the pika – possibly the cutest of all global warming refugees.He makes his home in cool alpine rock fields known as “talus” to the scientists. Perhaps you’ve seen this tiny, rabbit-like critter while hiking close to timberline, probably scurrying from boulder to boulder then ducking to his safe shade below the rocks to hide from birds of prey and the hot afternoon sun. He likes it cold. He thrives in chilly climates. His metabolism is like a furnace. He never hibernates and never sheds his thick fur coat. He won’t last too long even in crisp 75 degree weather.So what happens when his preferred home becomes much warmer?He dies. Man-made climate change is pushing pika populations up the mountains – closer to their preferred colder temperatures, and perhaps closer to extinction, says scientist Chris Ray, a researcher at the University of Colorado.It seems that this little creature we pass everyday on our favorite trails has become a very real example of how global warming is changing the earth.”An animal that humans don’t directly impact is starting to disappear from a lot of locations,” Ray said. “It should give us pause to what we’re doing to the environment.”
While listening for pika calls halfway up Notch Mountain, near Red Cliff, Ray tells a group from the Gore Range Natural Science School how small pika populations are going extinct at lower elevations. She spent an entire morning with the science school looking under rocks for their waste and the hay piles that sustain them through long winters. They come across an area where pikas apparently used to live, but don’t anymore.Pikas spend much of their day scampering around the talus, collecting enough flowers, leaves and grass to dry and store in hay piles hidden under the rocks. During the winter, that hay pile will keep them from starving, and the snow pack acts like a blanket, keeping the pikas warm enough to survive harsh cold snaps.So, another reason pikas are dying off at lower elevations, ironically, could be the cold. With less snow cover due to global warming, pikas lose that thermal blanket, and those cold snaps are actually killing them, Ray said.”We’re discovering a lot of half-eaten hay piles in the empty colonies,” Ray said.Ray says their trek up the mountain sides seems to be quickening. At monitoring sites, the lowest elevation pika populations have been spotted has climbed 10 meters a year for the past decade. It was about one meter a year for the good part of 100 years. Studies haven’t been done yet in the Rocky Mountains though, which is actually the largest home of the pika.”It’s very likely if they continue up hill at that rate, they’ll be gone in about 200 years or less,” she says.
While temperatures, both hot and cold, seem to be the best explanation for the dying pikas, global warming could be changing other aspects of pika life.The pika is very careful about what it eats – certain plants in the winter, certain plants in the summer. If global warming changes the balance of the pika’s food source, that could make a big difference.What if there are diseases that come up the mountain due to warmer temperatures and, for instance, take a toll on mice populations? Predators would then become more reliant on the pika for food.”Pikas are at the bottom of the food chain, and if there are more predators because they are moving up the mountain in response to climate change, that could effect them,” Ray said.Ever see a marmot on a hike? Marmots and pikas have a hard to pin down relationship – pikas respond to marmot distress calls, pikas gather marmot waste and put it in their hay piles for some reason, and pikas crawl into marmot dens.With global warming changing the timing of alpine summers, marmots are hibernating differently now, which could also affect pikas.
Usually, when a population goes extinct, humans had some very direct role, perhaps overgrazing a field or bulldozing for a housing development, Ray said.With the pikas, who live high on the mountains and rarely come in direct contact with anything human, the chain-reaction impact of global warming is more complex and difficult to see. There’s still a lot of data that needs to be collected on the pika, especially in the Rockies, to figure out exactly what global warming is doing.”It makes me want to learn more and understand more,” said Ann Stevenson, community programs director at the science school. “I like that there’s evidence, but there’s a lot of theories that need to be researched.”The Gore Range Natural Science School plans to start monitoring the pika habitats they found on Notch Mountain, Stevenson said. They’ll be watching things like temperature, snowpack and of course if the pikas are still there.”We’re seeing if we can add to that research – otherwise, we’re just jumping to conclusions,” Stevenson said.
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