Warming Climate and Wildfires Threaten Pikas' habitats
American Pikas are little rabbit-like mammals that could fit in the palm of your hand. In fact, they are the tiniest members of the rabbit family: an adult pika is just as large as a tennis ball, and young pikas are the size of a fat walnut!
Pikas are often seen scurrying around rocky alpine slopes with their mouths full of wildflowers. This is because they prefer rocky slopes and graze on a range of plants, mostly grasses, flowers, and young stems. In the autumn, they pull hay, soft twigs, and other stores of food into their burrows to eat during the long, cold winter.
Pikas in the Rockies steal from their neighbours to survive
Pika is also known as the "whistling hare" for its high-pitched alarm call when diving into its burrow.
American Pika vocalizations (Greater Yellowstone Ecosystem)
American Pikas can be seen above the tree line in alpine terrain. Though most pikas in the lower 48 inhabit alpine ecosystems exclusively, some survive at lower altitudes where deep, cool caves are available, such as the ice tubes in California's Lava Beds National Monument. The map below shows the observations of Pikas in North America from the 1970s.
Pikas prefer colder habitats. They are believed to have evolved from Siberian ancestors that crossed the former land bridge between Asia and Alaska. They once lived across North America, but have been retreating upslope over the past 12,000 years due to the warming climate.
American pikas now live on high-elevation cool mountains west of the Rocky Mountains. They can be found in Montana, Wyoming, Colorado, Idaho, Washington, Oregon, California, Nevada, Utah, and New Mexico, as well as western Canada.
Click on the button below to zoom in to the areas you would like to explore!
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The most recent human-enhanced global warming has threatened Pikas' habitats. They have disappeared from lower elevations where they used to live and retreated back to higher elevations to find new homes.
According to this early study , "when pikas are deprived of the opportunity to retreat to favorable microclimates in rockslides, they are unable to tolerate the high diurnal temperatures found at lower elevations. Thus, high environmental temperatures apparently constitute major stress on dispersing individuals at low altitudes. "
Temperature also plays a role in pikas’ ability to move from place to place . Warm weather inhibits their movements, while cooler temperatures allow them to more freely colonize new habitats. Therefore, Pikas habitats which still remain at lower elevations are usually small and isolated. They are more often compromised by human activities, such as grazing by livestock .
A map can show a clearer picture of how our warming climate has impacted Pikas' habitats.
Legend of the map below showing the observations collected at different elevations in different years
First of all, let's spend a minute to understand the color of the dots on the map below. It uses a bivariate color scheme to show the observation of Pikas collected in different years and different elevations.
When looking at the map, find the colors at the four corners of the diamond as they show you the most typical cases of observations made in recent vs historical years at high vs low elevation.
In the Cascade Ranges, we see most observations are made in recent years but at relatively low elevation.
However, in the Sierra Nevada Mountains and Colorado Ranges, the majority of observations, no matter historical ones or recent ones, were located at higher elevations.
This indicates that recent observations, regardless of geographic regions, were mostly collected at high elevations!
The histogram of elevation of all the 3437 observations collected so far shows that the average elevation is about 2681 meters (8795 feet), and the median elevation is about 2905 meter (9530 feet)! The standard deviation is also large with a value of 903 meters (2960 feet), indicating the large range of elevation where Pikas have been found.
A scatter plot of the colored observation points also shows us that people recently more often found Pikas at higher elevations.
Then how about wildfires? How are Pikas doing in the areas that are frequently threatened by wildfires? How would they adapt to the more often and larger burnings near home? With the map below, swipe and compare the wildfires that occurred before (left map) and after (right map) the year of 2000, and explore how recent wildfires have become a serious threat to Pikas' habitats.
Compare before and after 2000 how wildfires affect Pikas' habitats
Advice from a Pika
A piece of advice from our beloved Pikas:
- Be alert
- Voice your opinion
- Save for the future
- Spend time in the mountains
- Catch a few winks!
How wise!! Then what should we humans do to help Pikas reclaim their mountains?
Reference:
- American Pikas : https://www.nwf.org/Educational-Resources/Wildlife-Guide/Mammals/American-Pika
- Pikas observations in North America were downloaded from iNaturalist: https://www.inaturalist.org/
- Wildfire perimeters were downloaded from the Wildland Fire Decision Support System (WFDSS): https://wfdss.usgs.gov/wfdss/WFDSS_Home.shtml
