A pika perching in Rocky Mountain National Park in 2011
Credit: Miguel Vieira, flickr.
The study, released in January, researched various pika populations in eight western national parks as a means to understand climate impacts on pikas throughout the nation. In all but three of the parks studied, scientists predict that pikas could be gone by the year 2100.
Undeniably cute and elusive, pikas are pint-sized, rock-dwelling mammals that spend their lives in the cold and rocky alpine terrain above tree line. Pikas are important indicators of ecosystem health because they are particularly vulnerable to changes in temperature.
In many of the national parks, rising temperatures due to climate change are a major threat, and the pikas, who live in snowy boulder fields, are not adapted to warm temperatures. As temperatures rise, other plant and animal species may be able to move upslope to cooler habitats. But pikas are especially sensitive to heat and already live at some of the highest altitudes. With no more mountain to climb, their habitat shrinks and becomes fragmented. These warmer temperatures could also melt the snowpack that the pikas use to survive the harsh winters in the mountains.
Beginning in 2010, scientists from the National Park Service, Oregon State University, University of Idaho and University of Colorado-Boulder studied the viability of pika populations based on changes in habitat and weather patterns, as well as considering genetic diversity. While rising temperatures were a factor in the disappearance of pikas, the study also found that habitat connectivity in the parks is an important part of the hamster-sized rock scramblers’ survival.
In Rocky Mountain National Park, for example, cold winter with little snow cover and warm summers are causing a feedback loop that is causing pikas to disappear.
"We've already seen local declines and even extirpation of pikas in this area," explains Dr. Chris Ray, a researcher from the University of Colorado Boulder.
In less than a century, only three of the eight national parks studied are predicted to have stable pika populations. Five remaining parks’ populations are vulnerable to local extinction.
Parks with a grim future for pikas
Crater Lake National Park, Ore.
Pikas at this park already live at the highest elevation possible. Warmer temperatures could mean less snowpack and therefore less habitat for the pikas. The existing population will likely decline by half.
Rocky Mountain National Park, Colo.
The outlook for the pikas at this park is grim, as increased high temperatures will decrease and fragment habitat, causing pikas to disappear.
Yellowstone National Park, Wyo.
Like Rocky Mountain National Park, this park is expected to get warmer and drier, and pika populations will suffer directly from heat stress.
Parks with an uncertain future
Craters of the Moon National Monument and Preserve, Idaho
There are a variety of a scenarios for the small and isolated population of pikas living at the highest elevations in the northernmost corner of this park. Although the lava flows provide good habitat, the warmer temperatures and low genetic diversity may cause local extinction.
Lava Beds National Monuments, Calif.
Like Craters of the Moon, this park is at a lower elevation. It may be possible for this pika population to continue to survive in the microclimates created by lava flows in the park, but their future is uncertain.
Parks where survival is likely
Grand Teton National Park, Wyo.
As long as the current pika habitat remains well-connected and expansive, the cold and wet conditions will likely continue and the current the pikas will thrive.
Lassen Volcanic Park, Calif.
The pika populations at this park may survive, despite warmer temperatures, due to a large region of well-connected habitat and sufficient food.
Great Sand Dunes National Park and Preserve, Colo.
This park will likely remain the coolest of the eight studied parks. The pikas will likely continue to live in the northern half of the park as long as their habitat remains connected and there is enough precipitation for pika-preferred plants to grow.
An important finding of the study was that pikas may be able to survive warmer temperatures if their habitat remains connected. For the three parks where pikas have the best chance for survival, habitat connectivity is crucial for gene flow between populations as well as the pika’s ability to move around to find the best rocks to live under. The pikas may be able to adapt if there are no natural or man-made structures hindering their movement in national parks.