There are probably too few insects in the Netherlands to pollinate plants

It has been known for a long time that things are not going well for insects in the Netherlands. But it now appears that plants that depend on insects for fertilization are also on the decline. And that is no coincidence.

Dutch researchers come to this conclusion in the magazine Journal of Applied Ecology. They base their findings on an analysis of 87 years of measurements at more than 365,000 locations in our country. “We looked at the different plant species, but also at factors such as nitrogen, humidity and acidity of the soil and combined this with data on insects,” says researcher Geert de Snoo. “That combination and the large time scale make this research unique.”

Conclusion
And leads to worrying conclusions. Because the research reveals that the Netherlands is losing so-called insect-pollinated plants. These are plants that depend on insects for pollination – and therefore their fertilization. “We see that the number of insect-pollinated plant species is decreasing, while the number of wind-pollinated species is increasing,” says researcher Kaixuan Pan. “There are therefore fewer and fewer insect-pollinated plants.”

Biodiversity
It is extremely worrying. Because the lion’s share of plants in the Netherlands depend on insects for pollination. “If these plants disappear from the landscape, it not only means that there are fewer plant species left, but also that there are far fewer seeds and fruits for birds and other animals,” Pan warns. “In other words: a sharp decline in biodiversity.”

Food security
But that’s not the only reason for concern. The researchers point out that our menu largely consists of insect-pollinated plants. “75 percent of crops are plants that are pollinated by insects,” says Pan. “If we lose these species, it is a threat to food security.”

Pollinator shortage
But why are insect-pollinated plants having such a hard time? The researchers naturally wondered that too. After previous research showed that insects in our country are not doing well, it seemed obvious that the consequences would eventually also be felt by plants that depend on these insects for pollination. But can the decline in insect-pollinated plants really be traced back to the decline in insects? The researchers think so. Of course, there are also other factors that could lead to a decrease in insect-pollinated plants – such as an increase in nitrogen, for example. But such factors often hit wind-pollinated plants just as hard as insect-pollinated plants. And what the researchers now show in their study is that the number of insect-pollinated plants is decreasing, while the number of wind-pollinated plants is increasing. And that can actually only be explained in one way, says Pan. “That difference is most likely due to a lack of pollination: there are no longer enough pollinators to fertilize these plants (the insect-pollinated plants, ed.).”

These are worrying results. But we certainly don’t have to take them for granted; the researchers still see opportunities to turn the tide. For example, they argue for limiting nitrogen emissions. “If we ensure that less of it ends up in nature, it can help local plants and insects.” In addition, according to the researchers, it is important to better protect natural grasslands – often rich in insect-pollinated plant species that have been threatened in recent years. “And we must continue to monitor to see whether these types of protective measures have the desired effect,” says researcher Koos Biesmeijer. “Both on the insects and the plants, because they are mutually dependent.”