UWEC CERCA 2025

Given the rapid expansion of human presence across the globe, coping with humans is an important aspect of life in the modern world for most animals. The California ground squirrel (Otospermophilus beecheyi) is a facultatively social rodent that has a long evolutionary history of residing near humans. While it is well understood that humans disrupt their foraging and social behavior, the role of humans and dogs on the stress physiology of these animals is unclear. As part of a long-term study, we live-trapped and released California ground squirrels and measured “stress” levels from fecal glucocorticoid metabolites (FGMs) using a fully validated enzyme-linked immunoassay (ELISA). Drawing from 12 years of data, we show that FGM levels vary across years but are elevated in areas with high exposure to humans and dogs. These patterns tracked variation in human activity across a gradient from high to low disturbance across our study site (from the south to the north). FGMs were repeatable for individual squirrels within and between years. Our findings offer insights into the relationships between anthropogenic disturbance and stress physiology over small temporal and spatial scales.