Environment
Insect die-off is progressing: what can individuals do?
A bumble bee flies towards a row of poppies lit by the morning sun. Insects are dying out across Germany, even in nature reserves. photo
© Sebastian Gollnow/dpa
The diversity of insects in Germany has fallen drastically. In order to avoid a further decline, processes in agriculture in particular must change. But even small measures can help.
Insects such as wild bees and butterflies are essential to the ecosystem. As pollinators of wild and cultivated plants, they play an outstanding role in agriculture and thus also in feeding the population. At the same time, a massive insect die-off is underway. And even in nature reserves.
A research project presented on Wednesday under the direction of the German Nature Conservation Union (Nabu) showed that a massive decline in insects in nature reserves, which was already documented in 2017, is continuing. “I feared that it would be so, I hoped that it would not be so,” said project manager Gerlind Lehmann from Nabu.
According to them, the project shows that the total mass of insects, which is directly related to species richness, has not recovered in any way. Exact figures are to be published in the coming months.
In 2017, a study by volunteer entomologists from the Krefeld Entomological Association showed that the total mass of flying insects in parts of Germany decreased by more than 75 percent between 1989 and 2016. According to Nabu, this trend has not changed in recent years.
No escape from pesticides
According to the results, a particularly serious threat to insect diversity is that nature reserves are often located in close proximity to fields on which insect-killing pesticides are applied. This has dramatic consequences for animals and biodiversity. “The bee is systemically important,” said the member of the Nabu management board, Konstantin Kreiser.
Many people are now aware of the problem – and they want to help. Parents build insect hotels with their children, cities and municipalities sow colorful flower strips between the highways and nature conservation organizations give tips for insect-friendly balconies and gardens. But do such small measures actually achieve anything? “Of course, every flower box on the balcony is always helpful,” says Jürgen Gross, President of the German Society for General and Applied Entomology. Especially in big cities, the effect of a large range of native plant species should not be underestimated. Of course, this does not save all bee species, but it does a lot of good for the insects. In addition, such campaigns are also important for the further education of children in matters of nature conservation: “You can’t protect what you don’t know.”
Good advice: create food sources in your own garden
For an insect-friendly garden, it is important to plant many native plant species, such as bluebells or bugloss. “But pastures are also very important food sources, especially in spring, when most wild bees fly,” explains the biologist. Many ornamental plants, on the other hand, cannot be used by insects. These included rhododendrons or roses with double flowers that had no nectar. You should also do without an ornamental lawn and prefer a meadow with many different herbs.
According to Gross, nesting aids such as insect hotels are also a good and helpful measure – especially for wild bees. About half of the 570 wild bee species in Germany are threatened. “If you set up a nesting aid, you should build it yourself,” advises Gross. In finished models from the hardware store, the holes are often not well drilled. As a result, there is a risk that insects will injure their wings when crawling in.
Gravel gardens are an absolute taboo for the biologist. “They are hostile to every insect and every bird and also ensure a bad climate in the city.” At high temperatures, the stones heated up and additionally warmed the air. In several federal states and numerous municipalities, the creation of gravel gardens is no longer permitted.
Because stones, concrete and asphalt are obviously unattractive to insects, many cities are now retrofitting. Green roofs of bus stops in cities like Hamburg and Bottrop are just one example. An initial assessment from Hamburg shows that campaigns like these definitely have added value for insects: last year, 49 different wild bee and wasp species were found on just two green shelters in the Hanseatic city. Among them were rare and endangered species as well as gold wasps that had not been found in Hamburg before, it said.