Population dynamics and life strategies of seed predators are strongly influenced by the occurrence of fattening events (=seed production) of their respective main food resource. Mast tree species such as the European beech (Fagus sylvatica) are in turn strongly influenced by climate change. For example, an increase in the frequency of full fattening years in beech can be observed due to rising summer temperatures.

The dormouse (Glis glis) is a seed-consuming rodent species with an extreme adaptation to the availability of seeds from the European beech. Both reproduction and survival are directly related to seed availability. The reproduction of the dormouse is coordinated with the beech in such a way that dormouse young are born in August when the beech seeds are ripe and offer an optimal supply of food. In so-called down years, when few or no beech seeds are available, the edible dormouse abstain from reproducing. In these years there are not enough high-fat seeds available that the young animals need to build up enough fat reserves for their first hibernation. How does the beech fattening, which has changed due to climate change, affect the life strategy of the dormouse? Are there also more reproductive years for edible dormouse due to more frequent full fattening years? And how does this change the survival probabilities of the adults?

In the long term, climate change may lead to further changes in the dormouse habitat. Both forestry measures and the shift in the ecological niches of tree species due to climate change can lead to the following change: Forests that were previously dominated by beech will transform into forests in which there is a higher degree of mixture with other tree species (e.g. conifer species) exists. It has already been shown that high tree species diversity is beneficial for dormouse. But how does this change affect the dormouse population in the long term? To what extent will dormouse reproduction and lifespan change? Can the animals adapt fast enough? Climate change is progressing so rapidly that the remaining beech trees in the dormouse habitat are experiencing heat and drought stress. High summer temperatures and droughts in the coming years will mean that the beech will shed its seeds early and the quality will be correspondingly poor. The consequences of completely eliminating beech seeds as food for the dormouse are still completely unclear.

We want to answer the questions asked here with the help of a long-term catch-recapture dataset (2006 to date) of a free-living dormouse population near St. Corona am Schöpfl in the Vienna Woods Biosphere Reserve. Among other things, the age, sex, weight and reproductive status of each of the marked individuals are available to us.

Funding: Society for the Advancement of the Research Institute of Wildlife Ecology

Project start: October 2022