Wyoming Wildlife - October 2018

The importance of a good meal




New research suggests pikas may choose what and when to eat to buffer their bodies against warming alpine temperatures


10/1/2018 12:00:00 AM

We went to look for bears. Perched on a rocky ledge overlooking Lodge Grass Creek in the Bighorn Mountains, my husband and I scanned the valley below searching for wandering ursids that had recently emerged from their dens. But after several minutes, the sounds of a small critter behind us caught our attention.

We were sharing the rock with an instantly recognizable animal. With a blunt nose, a mouth full of food and two large Mickey Mouse-ears on its head, the American pika is easily identifiable. It eyed us suspiciously for a few seconds before resuming the activity that, for a pika, defines much of its waking hours — foraging.

It is this constant search for food that was the focus of a recently completed research project in the Bridger-Teton National Forest. As an alpine dweller, the pika is well-adapted to the extreme environment it inhabits. But as the climate warms, this environment is changing, and a University of Wyoming graduate student wanted to know: can pikas cope with the change and if so, how?

The American pika is a member of the rabbit family, or lagomorphs, a group of animals known for short lives and high rates of reproduction. But the pika shares few qualities with its relatives. They display a variety of vocalizations compared to their quieter cousins, including some sounds that are unique to Wyoming populations.

Females reproduce rather slowly, giving birth to just two litters of two to three offspring a year; generally only one litter will survive. In comparison, snowshoe hares may have up to four litters per year, with four to eight offspring in each. And while more than half of snowshoe hares will not reach their second birthday, pikas, if they survive their vulnerable first year of life, have the potential to live five to seven years.

But perhaps the most unique trait of the pika is its choice of habitat. While some rabbit and hare species can be found in a variety of habitat types, pikas are uniquely adapted to live in one of the harshest environments on the planet — the alpine zone. Though they have been documented living as low as 5,700 feet, they are primarily found from 8,000 to 13,000 feet, often on talus slopes, the jumble of rocks that accumulates at the base of mountain cliffs. At these heights, the perils are many. During winter months, winds pummel the barren rocky crags, snow piles several feet high and temperatures rarely get above single digits.

Other animals share this space with pikas for at least part of their lives, but most of those species find compromises must be made. Elk access high elevations in many of Wyoming’s mountain ranges, seeking nutritious forage during the summer, but retreat to the foothills in winter. Other alpine residents such as marmots, ground squirrels and chipmunks are closely tied to high-elevation habitat, but they hibernate during the winter months when it makes more physiological sense to suspend daily operations than to attempt to access food buried beneath feet of snow.

But pikas do not retreat, and they do not hibernate. They remain active during the winter, scurrying beneath the snow in tunnels and munching on stashes of vegetation accumulated during the summer, known as haypiles.

Adapting to such an extreme environment means the pika has pushed the boundaries of biology and luck. And to excel at alpine living, the rules are rigid. The pika is so well-suited to cold weather that balmy and comfortable temperatures for humans are life threatening to pikas. Their resting body temperature of 104 degrees is within just five degrees of being lethal, so exposure to outside temperatures above 77 degrees for just a few hours can cause hyperthermia and death.

Being so precisely adapted to their environment leaves these animals vulnerable when conditions alter and the climate warms — and the pika’s alpine habitat is changing fast. Average temperatures have increased around the world in recent years, but alpine zones have been particularly affected. The average temperature increase in the northern Rockies is nearly three times the worldwide average.

Concern about pikas and how they are faring in a changing climate has led to petitioning and denial for listing under the Endangered Species Act twice in the past decade.

Though research has shown pikas in the Great Basin area of Utah, Nevada and Oregon have declined by 25 percent in recent decades, population trends in Wyoming are not as well-known.

“We have a pretty good idea of where they are in the state,” said Nichole Bjornlie, a Game and Fish nongame mammal biologist. “They are in almost all of our mountain ranges except the Black Hills. But one of the things we are lacking for this species is population trends in the state. We’ve funded research projects and the next step is to get a handle on how they are doing long-term. As their environment changes and they get stressed, it becomes that much more important that we know what they are doing.”

Bjornlie hopes dedicated monitoring efforts might take place in the future, but funding has been limited due to the significant field work it would require to track and monitor pikas. However, a recent research project shows there is hope for how pikas might cope with rising temperatures in coming years.

Embere Hall weighs a sample of live plants collected from the area where a pika foraged. Vegetation mass helps researchers determine the amount and moisture content of the plants pikas cache under different temperature conditions. (Photo by Embere Hall/WGFD)

Changing behaviors

“Pikas are sort of living on what we might think of as the front lines of climate change,” said Embere Hall, the Wyoming Game and Fish Department wildlife coordinator in Laramie, who recently completed her dissertation on pikas and climate change through the University of Wyoming. “In the early 2000s, this idea came out and was published in science magazines that pikas and other alpine-adapted species that need this cold environment would march up the mountains so to speak (seeking cooler temperatures) as climate change progressed, until there was nowhere else to go.

“The bulk of my work was trying to understand whether or not they could make changes in their behavior to buffer some of the effects of changing climate,” she said. “We looked at what they ate and when they were eating.”

Eating is one of the defining characteristics of a pika’s life. If they are not actively engaged in gathering their daily sustenance, they are busy accumulating food for later use, stored in haypiles that can be the size of a bathtub. This frantic feeding and caching of food can only take place once snows have receded and vegetation greens up.

“Over the course of three to four months, they have to consume the food they need to get through the day and simultaneously cache the food they will need to get through the winter, which is a unique strategy and really quite interesting,” said Hall.

When she began her study, Hall anticipated two foraging strategies that were likely to be implemented by pikas trying to adapt to a warmer climate. One theory was that in warmer temperatures, pikas would forage quickly on the nearest available plants and then retreat to rocky crevices, or microrefuges, which provide cool, shaded areas where they could find a place to maintain their lower temperature.

Her other hypothesis suggested that, because foraging in warmer temperatures was physiologically taxing, the pika would seek forage with higher nutritional value, rather than forage what was easily accessible, but less nutritious.

She studied 72 individual pikas in the Bridger-Teton National Forest by placing cameras inside rock cavities where pikas were active and monitoring the type and amount of food they stored in their primary haypiles. The cameras were synchronized with temperature gauges that allowed her to link the type of food collected with the outside temperature.

“What we found is that they really strongly conformed to the high-risk-high-reward idea,” she said. “If they foraged when it was hot, they collected food that was higher in nitrogen. Nitrogen is very critical for animals, especially those in alpine ecosystems where nitrogen tends to be limited.”

Some of the plants the pika stored included lupine, sulphur-flower buckwheat and Indian paintbrush. In general, these flowering plants, called forbs, tend to be high in nitrogen and are important for growth and maintaining body tissue.

If, as Hall’s research suggests, pikas change their behavior in order to mitigate rising temperatures, wildlife managers may be able to pursue management decisions that benefit the plant communities they tend to favor. Encouraging the growth of forbs and preventing the spread the invasive species at high elevations is one method. Another is making sure talus areas are protected, maintaining the jumble of rocks that offer shady, cool areas where pikas can retreat in warmer temperatures.

Embere Hall, the Wyoming Game and Fish Department wildlife coordinator in Laramie who did her dissertation on pikas and climate change, examines a haypile collected by a pika in the Salt River Range. (Photo by Embere Hall, WGFD)

How to help

Wildlife watchers can also play a part in helping pika populations.

“Surveys for pikas are quite field intensive, since it requires folks to get out where the pikas are — often at high elevation in backcountry environments,” said Bjornlie. “The biggest cost for surveys would be personnel time, since we don’t really need any specialized equipment to detect pikas. That’s why we are hoping to establish a network of volunteers to help with surveys. It’s beautiful country, a pretty charismatic species and this is a great opportunity to involve citizen scientists with routine and robust survey efforts.”

Until a formal citizen science program is formed, sightings of pikas can be emailed to Game and Fish at wgf-rareanimal@wyo.gov.    

Since 2009, Nature Mapping Jackson Hole, a program of the Jackson Hole Wildlife Foundation, has collected pika sightings from people recreating in alpine and subalpine areas. A simple online form allows individuals to make reports, noting where they found pikas or evidence of pika activity, such as scat or haypiles, how many pikas they saw, the elevation and habitat type they were in, what activity the pikas were engaged in and more.

An online training manual provides advice on how to identify their vocalizations and other signs of pika activity. The mapping effort focuses on areas near Teton County, but any sighting in the Greater Yellowstone area can be reported on the Nature Mapping website.

“I think that as residents of Wyoming, we are really lucky to live in a place that, with a little bit of effort, we can see an animal that is as incredible as a pika,” said Hall. “If you have the chance, take the time to do it. They are fascinating because of their behaviors and unique strategies for making it where most animals don’t hang out during the winter. They have figured out a way to make a living in a pretty difficult environment.”

Christina Schmidt is the Wyoming Game and Fish Department’s public information officer for the Sheridan region.

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