Pika Research in the North Cascades
National Park Service Complex in 2009 and 2010
The Pika in the North Cascades
• The American pika (Photo 1) is a small mammal that lives only in talus patches located in
habitats ranging from low elevation forests up to high elevation alpine meadows in the North
Cascades National Park Service Complex.
• Pikas are considered to be a climate change indicator species because of their
sensitivity to high temperatures and obligation to talus habitat.
• Climate change may affect pikas through changes in foraging behavior owing to summer Photos 2, 3 & 4. From left to right, examples of talus patches at low (472 m), middle (1,464 m), and
high (2,118 m) elevations in the North Cascades National Park Service Complex.
temperature increases, alterations in vegetation across elevations that may affect forage
availability, and changes in winter snowpack and temperature patterns that may
negatively influence survival. Additional Key Results
• Pika abundance in talus patches was negatively correlated with the
minimum temperature recorded beneath the talus surface during
Field Methods and Results surveys (Figure 1), suggesting as sub-surface temperatures
• In summer 2009, surveyors gathered data on pika abundance, habitat increased, pika abundance decreased.
attributes, and temperature in 115 talus patches contained within 30 • Total pika abundance in 1-km2 survey areas was positively
1-km2 survey areas throughout the North Cascades National Park correlated with elevation (Figure 2) and an interaction between
Service Complex. Surveyors found pikas in 74% of talus patches and 90% elevation and the proportion of vegetation cover in patches,
of 1-km2 survey areas, with abundance per survey area ranging from 0 to 101 pikas. suggesting higher elevation survey areas and those with more
• In summer 2010, surveyors revisited 58 of the 115 patches included in 13 of the 30 1-km2 cover supported more pikas compared to lower elevations. This
survey areas, and found pikas in 76% of patches and all 13 survey areas, with abundance finding may be indicative of higher quality vegetation at higher
per area ranging from 4 to 106 pikas. elevations.
• During 2009 and 2010, surveyors found pikas in patches ranging in elevation from 351 to • The population growth rate in 1-km2 survey areas between 2009
2,130 m, which spanned the entire range of elevations for patches surveyed. and 2010 was negatively correlated with elevation, which is likely
• Surveyors recorded vegetation cover types within talus patches in a total of 1,932 1-m2 plots the result of a combination of winter and spring conditions resulting
in 2009 and 2010. The frequency of occurrence of vegetation cover types varied with in later snowmelt that varied with elevation. The growth rate was
elevation. Bryophytes and lichens occurred most frequently in plots at low and middle also positively correlated with the estimated average minimum daily
elevations, while cushion plants, forbs, graminoids, and shrubs occurred more often at high temperature during December 2009 through February 2010, which
elevations (Photos 2, 3 & 4). may be attributed to cold stress on pika over-winter survival.
70 120 • Because pika populations in the North Cascades National Park
100 Service Complex during 2009 and 2010 were influenced by multiple
40 climate and habitat factors—notably temperature, elevation, and
resource availability—the potential exists for pikas to be adversely
10 20 affected by climate change in future years. While many of these
0 0 effects could take many decades to manifest themselves,
30 40 50 60 70 80 90 0 500 1000 1500 2000 2500
especially for pika populations at higher elevations, changes may
Temperature (F) Elevation
Photo 1. A pika in a low elevation talus Figure 1. The negative correlation between pika Figure 2. The positive correlation between
become apparent in lower elevation populations on shorter time
patch in the North Cascades National abundance in talus patches and the minimum total pika abundance in 1-km2 survey areas scales.
Park Service Complex recorded sub-surface temperature (ºF). and elevation (meters).
Jason E. Bruggeman1, Roger Christophersen2, Regina Rochefort2, Robert Kuntz2 , and Rachel Richardson1
1--Beartooth Wildlife Research, LLC, Farmington, MN; 2--National Park Service, North Cascades National Park Service Complex, Sedro-Woolley, WA. Funding for the study was provided by Seattle City Light’s Wildlife Research Program.