Bees fly across meadows in search of flowers, hedgehogs wake up from their hibernation: what actually heralds the beginning of spring sometimes happens as early as January this year. Mild temperatures throw nature out of rhythm. “Our ecosystem is coordinated,” explains Julian Heiermann, nature conservation expert at the Nature Conservation Union (Nabu). Insects that fly earlier would then also need food plants. “That’s usually synchronized in nature. If it gets even more extreme now, and there might be no winter at all at some point, I’m concerned that it will get out of step.”
The temperatures at the beginning of the year have so far been exceptionally mild. “In terms of temperature, January is constantly flying high,” wrote the German Weather Service (DWD) after the first week of January. It has been changing for weeks, he said recently. “It feels more like windy fall weather than winter.”
Due to climate change, there are more weather anomalies such as dry, hot summers or warm and too dry winters, says Derk Ehlert, wildlife expert at the Berlin Senate Department for the Environment. These changes affected plants and animals differently – but mostly to their detriment. A healthy, strong stock can cope with such changes better, says Ehler. “But animals and plants weakened by dry summers, heat and drought could react to this.”
The specific effects of the weather vary from animal to animal. The rough control of hibernation and hibernation works through an internal clock, says Heiermann. “But if it’s been very mild for a long time, the fine control doesn’t work. This can mean that the animals are already becoming active, even though it’s still too early.”
For example, if a hedgehog wakes up earlier than usual, then it also needs energy earlier. For this he consumes the so-called brown fat, says Ehlert. This can be quickly converted into energy. “When it gets colder again, the animals then lack the energy for the actual start of spring.”
But other animals can also have problems in mild temperatures. With honey bees, for example, it could be fatal, says Ehlert. These would then fly off and find no flowers. “Even frogs can spawn too early.”
But mild winters also have winners. “The wild boars are certainly happy about the weather conditions,” says Ehlert. “They get into the ground well and can forage for food.” According to experts, birds from Northern and Eastern Europe also benefit from loose soils and find more food as a result. “We notice that directly at the feeding places. They are not visited at all because the birds have enough food.”
And what about mosquitoes, which are rather annoying for humans? Do they also benefit from the temperatures? “In the case of mosquitoes, there are so-called population waves: If there is a short winter and a late onset of winter at the end of the year, then the mosquitoes produce more generations than in a shorter growing season,” explains Heiermann. “Then it quickly multiplies.” However, it is still too early to draw conclusions about the coming summer. “It’s true that more insects are surviving the winter, but the question is whether they’ll make it through the spring as well.”
The warm January is not necessarily a problem for some animals – but possible cold snaps after the mild phase. This is also problematic for plants. Late frost events could damage plants that have already sprouted, says Heiermann.
This could also become a problem in agriculture. “If the winter crops in agriculture shoot up earlier in the winter when temperatures are mild, then the crops are more sensitive to the subsequent frost than when they are small. And that can then lead to crop failures.”
Overall, dryness and drought in summer are a much bigger problem for nature than mild winters, says Ehlert. “As a result, many species are weakened.” Therefore, one should look forward to any rain at the moment. “But good news for January is that we have already achieved the necessary amount of rain for the first half of January,” he emphasizes. “The more rain falls in the winter months, the stronger nature goes into spring.”
