SPATIAL AND TEMPORAL HETEROGENEITY IN THERMAL CONDITIONS FOR WILDLIFE

Abstract

Temperature is an important component of climatic conditions that drive animal evolution, niche space, and life history traits. We used field-deployed temperature sensors and generalized linear mixed-effects models to quantify the spatiotemporal variation of ambient temperatures in three study areas of western Montana, in support of concurrent studies of moose ecology and population dynamics. We found substantial potential for thermal refuge for moose; temperature ranges observed simultaneously among sites within study areas averaged 7.0°C during summer and 6.1°C during winter. We considered 6 site variables hypothesized to affect local temperatures (elevation, topographic position, aspect, land cover type, forest canopy cover, and the interaction of land cover and solar radiation), and all contributed to model performance. However, the direction and magnitude of effects varied in a cyclic fashion during the 24-hour diel cycle, and in many cases, exhibited reversed effects between day and night. Although spatial heterogeneity in temperature during summer was only slightly higher than during winter, our ability to explain such pattern was much better during summer (average R² = 0.51–0.56) than during winter (average R² = 0.09–0.23). We encourage researchers and managers to explore field collection and spatiotemporal modeling of temperature sensor data for cost-effect description of thermal environments for wildlife in local settings.