Drought, deforestation, insect deaths - in many places the forest can no longer offer the garden dormouse a suitable habitat. As a result, populations of this once common rodent have plummeted. Instead of in the forest, the garden dormouse is now increasingly seeking refuge in our cities, as biologists have discovered. But the city as an ark cannot be a long-term solution, because natural areas are also becoming scarcer there. Therefore, it is now necessary to create retreats again to ensure the survival of the garden dormouse.
The little garden dormouse (Eliomys quercinus) is a relative of the dormouse and is particularly noticeable because of its black, spectacle-shaped head pattern, which is nicknamed the "Zorro mask". The rodent is nocturnal and hibernates for a long time from October to April - so it lives up to its name. The garden dormouse is even a minor celebrity, having been voted Animal of the Year in 2022 - but unfortunately for a sad reason: The populations of this native animal species, which was once found in large parts of Europe, have plummeted in Europe and Germany in recent years drastically decreased. But why the rodent has disappeared from many regions in such a short time has puzzled conservationists and scientists.
Where's the garden dormouse?
Therefore, the Bund für Umwelt und Naturschutz Deutschland (BUND) in cooperation with the University of Giessen and the Senckenberg Society for Nature Research launched the project "Tracking Garden Dormouse" and, after three years of intensive research, have now been able to shed some light on the matter. During this time, all conceivable factors that could affect the garden dormouse were examined. These included, among other things, food, predators, diseases, habitats and the distribution and behavior of the animals.
While fears of genetic impoverishment, which would have impaired the animals' ability to reproduce, were not confirmed, the decisive factor seems to be the loss of habitat: The small rodent prefers to live in diverse forests with bushes, rocky niches, sufficient deadwood and small cavities in trees . But the forest dieback as a result of the drought years in connection with intensive forestry seems to have left its mark on this species as well. "There is a lack of food, especially insects, one of the food bases of garden dormouse, as well as places to hide and retreat," emphasizes wildlife biologist Johannes Lang from the University of Giessen. Even a rodent as adaptable as the garden dormouse can no longer find suitable habitats in many regions of Germany.
From the forest to the city
It was also particularly striking that the garden dormouse was quite common in some cities in south-west Germany, while hardly any animals were found in many of its natural habitats. Lang explains that the cities along the Rhine, such as Wiesbaden or Mainz, have apparently become a kind of ark for the garden dormouse, in which they find suitable conditions for survival. What counts for the garden dormouse is above all a structurally rich habitat with many hiding places, which it seems to be more likely to find in some cities than in the forests stressed by drought and forestry.
But that's not a real alternative, emphasizes Mechthild Klocke, project manager of "Searching for Garden Dormouse": "Cities alone as a habitat don't offer the garden dormouse any perspective, we can't rest on our laurels". Because the cities are also changing, becoming more and more dense and losing the urban nature that currently serves as a retreat for the little rodent. In addition, the death of insects is also causing food shortages in the cities and the animal is also endangered there by the use of rat poison and pesticides.
give back habitat
Now that the "Tracking Garden Dormouse" project has provided information about the causes of the retreat of garden dormouse, the next step is to protect these rodents. That's why the team is now starting specific protective measures to give the little dormice a future again in all of its natural habitats. "We want to create retreats for the garden dormouse again, for example by planting, by allowing overgrown areas or specifically by offering nesting boxes," explains Klocke.
Similar to the first part of the project, this should again be done with the support of volunteers: "It is important to get people even more involved in nature and species protection: from the balcony owner to the allotment gardener, from the forester to the fruit farmer, from from the authorities to the communities. We want to show how everyone - whether privately or professionally - can work for the survival of the garden dormouse and thus for biodiversity in Germany," says Klocke.
Source: Senckenberg Research Institute and Natural History Museums / BUND