Climate change is forcing bats to hibernate earlier - consequences for nature conservation!

Climate change is forcing bats to hibernate earlier - consequences for nature conservation!

Biologists at the University of Greifswald have presented insightful results in a new study on how bats respond to climate change. The research shows that water bats (Myotis daubentonii) begin their hibernation almost a month earlier than they did a decade ago. This significant change has been documented over a period of 13 years, although the bats do not emerge from hibernation any sooner. The results were published in the journal on October 2, 2025Global Change Biologypublished. In the Münster area in particular (North Rhine-Westphalia), over 4,000 bats of two species were tagged with RFID transponders and monitored in order to closely track these changes.

A central point of the study by Dr. Gabriella Krivek and her team believe that water bats go into hibernation earlier because their main food, insect larvae, hatch earlier due to warming waters. In contrast, fringed bats (Myotis nattereri) shortened hibernation periods. However, these different behaviors could have long-term effects on the survival of the species, as young animals in particular appear to have difficulty adapting to the new conditions and visit them later in winter.

Climate change and its effects on hibernation

Climate change is not only causing earlier entry into hibernation, but also has far-reaching consequences for bats' hibernation areas. According to a report by science.de Research shows that warmer temperatures and shorter winters could expand bats' wintering areas. An increase of up to 14 percent to the northeast is forecast by the year 2100. Hibernating animals require cold temperatures to hibernate effectively; therefore, climate change is proving to be a serious threat.

The study also makes it clear that legal restrictions on access to winter shelters in Germany, which currently apply from October 1st to March 31st, may need to be adjusted. These measures are important for nature conservation, considering that the extended period of activity of the fringed bat should be taken into account in forest management. Background information about the flexibility of bats in terms of their food intake and hibernation was also collected through a literature review as part of a project by the Leibniz Institute for Zoo and Wildlife Research (IZW).

Changes in bat populations

The IZW's studies show that there are fundamental differences in the reactions of bat species to climate change. There are around 1,300 species of bats worldwide. While many bat species show positive reactions, for example by expanding their range, other species show negative trends, which are reflected in a reduction in biodiversity. Extreme events usually lead to negative or neutral reactions.

Important factors affecting bats' ability to adapt to climate change are their large surface area to volume ratio and low reproductive rate. Less than half of the studies to date have been able to provide concrete evidence of individual responses to climate change, so more empirical research is needed. Standardized study designs are essential to provide a comprehensive overview of these critical responses and to advance understanding of how biodiversity responds to the challenges of climate change.

The results of these studies highlight not only the urgency of combating climate change, but also the need to adopt specialized and adapted conservation measures to ensure the survival of bat species in their natural habitat.