Reproduction and hibernation in the edible dormouse

Certain ecosystems, such as European deciduous forests, are characterized by pulsed resource availability caused by the mast seeding of trees, which alternates with years of intermediate or completely absent seed production. The edible dormouse is a specialized seed predator which is highly adapted to these fluctuations in resource availability. Dormice are able to predict an upcoming mast, produce young just in time with maximum food availability, and can completely skip reproduction in years with a lack of seeding. Also, dormice show a strong trade-off between current reproductive investments and future survival, and can `sit tight` for several years until environmental conditions are favorable for reproduction. Thus, dormice provide an ideal model to investigate life history tactics adapted to pulsed resource environments. Several aspects of the ecology of dormice are completely unclear, however: Which environmental cues are used by dormice to predict a mast seeding and to adjust their sexual activity accordingly? How do factors such as body condition, age and reproductive history determine individual reproductive decisions (i.e., to breed or not to breed?) in years with intermediate seed production? How does reproduction affect survival chances? Is there an influence of reproductive effort on the duration and characteristics of hibernation, and on survival chances during winter? We plan to investigate these questions in a three year project that combines a capture-mark-recapture field study with measurements of body temperature patterns during hibernation under semi-natural conditions in outdoor enclosures. Regular checks of marked dormice inhabiting 200 nest boxes at a study site in the Vienna Forest will allow us to determine body condition, age, and sexual activity (estrus and testes sizes) in both sexes, to assess reproductive effort (litter size) in females, and to compare survival rates in summer and winter. Further, we will use implanted miniature temperature loggers to monitor body temperature patterns over two hibernation seasons to investigate their relation to prior reproductive effort. Results from our field study will be used to carry out sensitivity analyses of vital rates and to model the effects of pulsed resources on long-term population dynamics. Also, we plan to compare our results with data from other long-term studies in dormice under milder climatic conditions and to model effects of possible long-term changes in mast seeding frequency (as caused by global climate change) on dormouse population growth rates.

Certain ecosystems, such as European deciduous forests, are characterized by pulsed resource availability caused by the mast seeding of trees, which alternates with years of intermediate or completely absent seed production. The edible dormouse is a specialized seed predator which is highly adapted to these fluctuations in resource availability. Dormice are able to predict an upcoming mast, produce young just in time with maximum food availability, and can completely skip reproduction in years with a lack of seeding. Also, dormice show a strong trade-off between current reproductive investments and future survival, and can `sit tight` for several years until environmental conditions are favorable for reproduction. Thus, dormice provide an ideal model to investigate life history tactics adapted to pulsed resource environments. Several aspects of the ecology of dormice are completely unclear, however: Which environmental cues are used by dormice to predict a mast seeding and to adjust their sexual activity accordingly? How do factors such as body condition, age and reproductive history determine individual reproductive decisions (i.e., to breed or not to breed?) in years with intermediate seed production? How does reproduction affect survival chances? Is there an influence of reproductive effort on the duration and characteristics of hibernation, and on survival chances during winter? We plan to investigate these questions in a three year project that combines a capture-mark-recapture field study with measurements of body temperature patterns during hibernation under semi-natural conditions in outdoor enclosures. Regular checks of marked dormice inhabiting 200 nest boxes at a study site in the Vienna Forest will allow us to determine body condition, age, and sexual activity (estrus and testes sizes) in both sexes, to assess reproductive effort (litter size) in females, and to compare survival rates in summer and winter. Further, we will use implanted miniature temperature loggers to monitor body temperature patterns over two hibernation seasons to investigate their relation to prior reproductive effort. Results from our field study will be used to carry out sensitivity analyses of vital rates and to model the effects of pulsed resources on long-term population dynamics. Also, we plan to compare our results with data from other long-term studies in dormice under milder climatic conditions and to model effects of possible long-term changes in mast seeding frequency (as caused by global climate change) on dormouse population growth rates.