I’ve been studying pikas, little cousins of rabbits for over 50 years, and I’m not tired of looking at them. These tailless, egg-shaped down balls live mainly in cold mountain environments, in piles of broken rock, called talus.
During the summer, observers can see the pika carefully gathering clothes of grass and leaves in the hayfields that will serve as food throughout the winter. Their light brown coats blend well with the environment, so they are most easily noticed when perched on prominent cliffs and ring to alert other pike of their presence.
When fellow hikers see me watching pikas in the Sierra Nevada of California, they often tell me that they have read that these animals are becoming extinct. I’ve gathered a stack of press releases that say exactly that. But based on my recent research and a comprehensive review of over 100 peer-reviewed studies, I find this interpretation misleading.
Constrained by climate
As I showed in my first research, the biology of pikas suggests that they are likely to be affected by a warm climate. Most importantly, the normal body temperature is high, which puts them at risk of overheating when active in hot environments. When temperatures are warm, pike retreat to the much colder depths of their talus habitat.
Temperature also plays a role in the ability of the pikas to move from one place to another. Warm weather inhibits their movements, while colder temperatures allow them to colonize new habitats more freely.
A bit of ancient history is instructive here. Pikas originally came to North America from Asia and spread to the continent about five million years ago, in colder periods. Their remains were found in caves in the Appalachian Mountains and in the Mojave Desert – places where the Pikachis no longer live.
American pike live mainly in the alpine and subalpine mountain areas that extend south of central British Columbia and Alberta into the Rocky Mountains of New Mexico and the Sierra Nevada of California. Andrew Smith, CC BY-ND
As the world’s climate warmed, pika populations retreated to the high mountains of the western United States and Canada. Today, they occupy most of the talus habitat available in these areas – evidence that causes the pikas-on-the-margin narrative.
For example, in recent surveys, pika was found at 98% of 109 suitable sites in Colorado and 98% of 329 sites in central Sierra Nevada. A study of historic pika sites in California’s Lassen, Yosemite, Kings Canyon and Sequoia National Parks found no evidence that pikas have moved to new locations or higher altitudes due to climate change.
Pikas in warm environments
In contrast, most sites where researchers believe that pikas have disappeared are small, isolated and often compromised by human activities, such as animal grazing. These sites are generally lower and warmer than the sites in the basic range of pikas.
Many of these areas are in the Great Basin – a large desert region that stretches across most of Nevada and parts of Utah, Idaho, Wyoming, Oregon and California. A number of studies on a small number of marginal sites in the Great Basin previously occupied by pika have disproportionately contributed to the narrative that pika is likely to become endangered.
To investigate the overall picture of this region, we worked with state and federal officials on a 2017 study that identified 3,250 records of the pika habitat site. The pika were present at 2,378 places, were not found at 89 places where they had been seen since 2005 and absent from 774 places that contained only old signs of pika occupation.
The extensive and old sites had the same temperature and precipitation ranges as the places where pika was still present. This suggests that non-climatic factors could have caused pikas to disappear from vacancies.
Pika have disappeared from parts of the Great Basin, but climate change may not have been the cause. Kmusser / Wikipedia, CC BY-S
Pika are still present in other remarkably hot places, such as the ghost town of Bodie, California, the nearby Mono Craters and the Moon Craters in Idaho. In these places, pike retreat to the cold corners of their talus habitat during the hottest part of the day and often feed at night.
In my research, I also found that Pikas were much less active and made much fewer calls to these low-altitude sites compared to high-altitude Pika populations. In low-lying areas, pika consumed a diverse diet of plants in the large basin, such as the large toothbrush and the bitter brush, which was significantly different from the plants they consumed in high-altitude areas. Some have not even managed to build their characteristic meadows.
Another atypical pika population lives near sea level in the Columbia River Gorge in Oregon. And here they have adapted well to a very different habitat, surviving throughout the year with a diet consisting mainly of muscle. It defends the smallest territories of any pika and, when it warms up, it simply moves away from the slope and sits in the shade of the nearby forest.
A future for Pikas
Based on my analysis of dozens of studies, pika populations appear to be safe in their core area – the mountains of western North America, which have a large and fairly well-connected talus habitat. In these areas they can move from one patch of habitat to another without having to go through areas that are dangerously hot for them.
The fact that pikas have also adapted to a number of marginal, hot environments suggests to me that they are more resistant to climate change than many past studies have concluded. Most species have losses near the edges of their geographical areas, simply because the individual animals in those areas live in conditions less than ideal for them. This does not mean that they will go out.
Climate change is the most critical issue facing the world today, so it is especially important for scientists to accurately communicate this to the public. In my opinion, the fact that spikes cope and change their behavior in response to changing conditions is encouraging news for future naturalists who aim to observe one of nature’s most charismatic mammals.
Andrew Smith is Professor Emeritus of Life Sciences at Arizona State University.
Disclosure Statement: Andrew Smith does not work, consult, hold shares or receive funding from any company or organization that would benefit from this article and has not disclosed any relevant affiliation beyond his academic appointment.
Reposted with permission from The Conversation.
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