Spatio-temporal foraging behavior, habitat selection and impacts of bio-logging on Eurasian beavers, Castor fiber

Abstract

Wild animals deal with a dynamic landscape consisting of both food resources and threats that vary across space and time. This thesis investigated spatio-temporal foraging behavior and habitat selection of Eurasian beavers (Castor fiber), while also exploring potential negative impacts of the methods used to study their behavior. We explored how sex, age, reproductive status, body condition, and density impacted beaver behavior. Through tagging beavers with VHF transmitters and GPS loggers, we could track beaver movements and behavior across the landscape, seasons, and the night. We found that reproductively active females displayed similar foraging patterns as males, but differed in seasonal activity patterns, habitat selection, and diet during certain times of the year. The socio-reproductive groups also differed in circadian habitat selection patterns, revealing potentially different strategies in balancing foraging and risk. These differences indicate that even monogamous and monomorphic species may display sex-specific behavioral differences and differences related to age and other physiological and demographic characteristics. We found that beavers foraged extensively on cereals during late summer, which may play an important role in beaver foraging ecology and body condition. Beavers tagged with bio-loggers displayed lower weight gain during the tagging period, but the difference was small and there was much individual variability. There was also considerable individual variability in beaver habitat selection, some influenced by age and other beaver-specific characteristics, but much remained unexplained and raised new research questions. We concluded that beaver behavior is highly dynamic and variable across time and among individuals, which highlights the complexity of wildlife behavior and interactions within the ecosystem.