Modeling behavioral thermoregulation in a climate change sentinel.

Area of Science:

• Ecology
• Climate Change Biology
• Physiology

Background:

• Species are predicted to shift ranges in response to rising temperatures.
• Behavioral thermoregulation is a key mechanism for animals to tolerate environmental change, influencing geographic distribution.
• Understanding behavioral thermoregulation is crucial for predicting species' responses to climate change.

Purpose of the Study:

• To mechanistically model microclimate conditions and thermoregulatory behavior for the American pika (Ochotona princeps).
• To investigate the link between daily activities and thermoregulation needs in a temperature-sensitive mammal.
• To assess the role of fur properties and body size in pika adaptation to climate change.

Main Methods:

• Utilized the biophysical model Niche Mapper to simulate microclimate and thermoregulatory behavior.
• Collected empirical metabolic chamber data for various fur properties, body sizes, and environmental parameters.
• Conducted 288 hours of field observations of pika behavior and thermal characterization in Glacier National Park, Montana.

Main Results:

• Niche Mapper accurately simulated microclimate and predicted behavioral constraints due to thermoregulation needs.
• Pikas exhibited reduced activity above 20°C, aligning with model predictions.
• Smaller body size and summer pelage could benefit low-elevation pikas under future warming scenarios.

Conclusions:

• Mechanistic predictions and empirical observations of pika thermoregulation were congruent.
• Fur properties and body size are critical factors for pika populations responding to climate change.
• Behavioral thermoregulation and microclimate variability are important considerations for predicting animal responses to climate change.