The Crestone Eagle • March, 2021

How is climate change impacting the American pika?

by Zaylah Pearson-Good 

The American pika is quick to introduce itself to any hiker who ventures above treeline. Small and attentive, it peeks out from its rocky den to release a high-pitched chirp, alerting its colony that visitors have arrived. Crestone hikers know this squeak well, as it is the soundtrack to any journey up to our beloved alpine lakes. Many passersby are charmed by these adorable critters, yet few realize that the future livelihood of the species has been a hot topic among environmentalists for years. 

Due to their naturally high body temperature of around 104°F, pikas thrive in cold, moist climates along the western mountain ranges of North America. Weighing roughly six ounces each, these petite creatures enjoy a chilly habitat above 8,000 feet. Foregoing hibernation, pikas experience the full extremes of winter, surviving off of stockpiled plants and flowers (haystacks) that were collected and dried during summer months. Terry Terrell, with the National Park Service, wrote that these haystacks sometimes are equivalent in size to the average bathtub and offer critical food security during cold, barren months. 

Evidence suggests that pikas are more resilient against climate change than we once thought.

Since the American pika has biologically and behaviorally evolved to live in very cold environments, they are especially vulnerable to climatic fluctuations. As a result, many conservationists refer to the American pika as an indicator species of climate change, similar to the polar bear. The National Wildlife Federation (NWF) reports that the American pika is so heat-sensitive that temperatures exceeding 78°F can be fatal. Furthermore, many scientists predict that as global temperatures increase with climate change, species will gradually seek refuge at higher altitudes. Since most pikas already live in alpine ecosystems, they are limited in their ability to migrate to higher, cooler grounds . . . They already live at the highest habitable points. 

As a result of climatic, geographical, and habitat constraints, scientists have warned that climate change puts pikas at a heightened risk for extinction. In a report on the American pika, NFW laments that “Without protection and help, American pikas could be the first species to go extinct due to climate change.” NFW adds that the species has already “disappeared” in over 1/3 of their habitat in Nevada and Oregon. Climate change could also bring unwelcome changes to pikas’ food supply and introduce new predators and pests that may further stress the species. 

Pikas are abundant along most high-altitude hikes above Crestone. Pictured is the Venable-Comanche Loop trail.

Despite the concern for pikas across the US, evidence is emerging to suggest that these fierce furballs are more resilient than we previously thought. Andrew Smith, a professor emeritus of life sciences, has been studying pikas for over half a century. In January 2021, Smith wrote in The Conversation that the pika is “not as threatened by climate change as many studies have warned.” Backed by his own research and more than 100 peer-reviewed studies, Smith reports that pikas are not on the trajectory towards extinction anytime soon.  

Understanding the American pika’s evolutionary history offers some insight into how they might fare against today’s changing world. Smith reflects that throughout time, the species has already adapted to extreme fluctuations in climate. Believed to have migrated from Asia roughly 5 million years ago, pikas once inhabited parts of North America that no longer support modern descendants. For example, Smith notes that regions now uninhabitable for pikas, such as the Mojave Desert and the Appalachian Mountains, once supported their ancient ancestors because the global climate was much colder. Many pikas began to seek cooler temperatures upslope as the globe began to warm. 

However, not all pikas retreated to high-altitude habits. In fact, some pika populations are present in warmer, lower elevation sites, such as Craters of the Moon National Monument and Bodie, California. Smith found that pika behavior shifts in these hotter, lower elevation climates: their diet diversifies, they decrease their activity, and they make fewer noises. They also spend more time foraging at night when temperatures drop, and spend much of the day in the shady nooks of their dens. Additionally, the diet of pikas living along Oregon’s Columbia River Gorge consists almost exclusively of moss—an unusual trait for the typical haystacking pika. Though these warmer, low-elevation colonies are not as numerous, it is promising to know that the species is capable of adapting to different environments. 

Pikas generally live in rocky, high altitude habitats that exist along the Western mountains of North America.

Smith admits that parts of North America have definitely seen losses in pika populations, but he is not convinced that climate change is to blame. Generally speaking, disappearances have been observed outside of the species’ core range. The Great Basin, a deserted terrain encompassing parts of Utah, Idaho, Oregon, California, Wyoming, and most of Nevada, has seen the majority of population declines. However, Smith reports that sites that experienced significant pika disappearances did not deviate in temperature or precipitation from sites where pikas were still thriving. As a result, variables unrelated to climate are believed to be responsible for species loss, such as livestock grazing. 

Overall, pikas seem to be doing well in their core habitat (North America’s western mountain ranges). According to surveys cited by Smith, 98% of sites observed in the central Sierra Nevada hosted healthy pika populations. The same statistic is true for sites monitored in Colorado. 

While the future of the American pika may be more promising than previously thought, we should not take this species for granted. From unprecedented glacial melt to extended droughts and wildfire seasons, the impacts of climate change are still being revealed. An assessment by NASA reports that global average temperatures have risen by over 2°F since 1880. Temperatures are expected to continue increasing, leaving the fate of countless species unknown. However, one thing is known: each of us has a duty to live mindfully on this planet. To be a thoughtful steward of the environment is a choice that we should all make. We do not need the demise of any species to tell us that. 

Interested in a meaningful project that contributes to our understanding of the American pika? PikaNet, a citizen science initiative under the Mountain Studies Institute, trains volunteers to collect data on pikas in the southern Rockies. Inquire with Jeremy May at jeremy@mountainstudies.org to see how you can help!  

Sites referenced: 

https://www.nwf.org/Educational-Resources/Wildlife-Guide/Mammals/American-Pika

https://theconversation.com/pikas-are-adapting-to-climate-change-remarkably-well-contrary-to-many-predictions-150726

https://www.nps.gov/romo/pikas.htm

https://earthobservatory.nasa.gov/world-of-change/decadaltemp.php