Many species rely on microclimates (i.e., areas where temperature and weather differ from prevailing conditions) for protection against climatic extremes. American pikas (Ochotona princeps) are small, climate-sensitive lagomorphs that inhabit rocky habitats across western North America. While warming summers and reduced snowpack have driven population declines in parts of the pika’s range, the degree to which microclimate refugia are also changing remains poorly understood. We analyzed 14 years of temperature data (2011–2025) from four sites in the Columbia River Gorge, where cool, stable microclimates enable pikas to survive at their lowest elevation. We also evaluated the effects of the 2017 Eagle Creek Fire on microclimates at these sites. Since 2011, talus surface temperatures have increased by ~0.32°C per year, and while subsurface interstitial environments also warmed slightly, they remained consistently 6–11°C cooler than surface temperatures. Despite this buffering, the frequency of hot days (>25°C) rose by ~7% annually, both before and after the fire, increasing potential exposure to heat stress. These results underscore both the resilience and vulnerability of pika habitats: talus continues to mitigate extreme heat, yet climate warming and wildfire appear to be eroding this buffer, with potential consequences for persistence in this unique low-elevation habitat.

Dr. Johanna “Pika Jo” Varner is a professor of biology and pika biologist at Colorado Mesa University, and past chair of the North American Pika Consortium. Her research has generally focused on understanding how some populations of pikas persist in seemingly “marginal” habitats, including the Columbia River Gorge, Craters of the Moon, and several isolated mountain ranges near the species’ southern range edge. She has also led several participatory science programs that invite volunteers and/or K-12 students to participate in pika monitoring activities, and last year, she oversaw the development and release of the “Pika Patrol” participatory science mobile app.