Moose habitat selection and movement dynamics in a changing thermal landscape under climate change : accounting for circadian rhythmicity using harmonic terms

Sammanfattning

Climate change is intensifying the frequency and severity of heatwaves in boreal regions, posing challenges for heat-sensitive species like the moose (Alces alces). As a large-bodied herbivore with limited heat tolerance, the moose is especially vulnerable to rising temperatures. This thesis examined fine-scale movement and habitat selection of 300 GPS-collared female moose across four ecological strata in Sweden during heatwaves. Time-varying Step Selection Functions and space-time regression kriging were used to analyze behavioral responses to thermal stress. Moose reduced daytime movement during heatwaves, suggesting behavioral thermoregulation. Habitat selection shifted in some regions, with increased use of forest and wetland habitats during midday, indicating preference for thermal refuges. Moose also selected lower elevations in certain strata, likely to access cooler microclimates, while proximity to water did not consistently influence selection and was avoided in open alpine wetlands. These findings reveal that moose employ spatial strategies to cope with heat, emphasizing the importance of landscape features in buffering thermal extremes. Such insights are crucial for anticipating climate impacts and guiding wildlife management in a warming world.