Bees and other pollinators under serious threat, new counting method should help

Cees DetermannA large silk bee in a dandelion

NOS Nieuws•vandaag, 18:24

Francien Intema

Interior editor

Francien Intema

Interior editor

Slowly walk half a kilometer and count how many bees and other pollinating insects you see: volunteers are now being trained in this all over Europe. Pollinators are having a hard time and, according to the European Commission, this also threatens our food security, our well-being and the economy. The Commission wants to turn the tide in 2030 and a new monitoring network should help with that.

People daily benefit from the work of these insects. According to the European Commission, about 4 out of 5 food crops and flowering wild plants in Europe are (partly) dependent on pollination by thousands of insect species. In this way, they make an important contribution to agricultural yields and they contribute to the health and resilience of ecosystems.

But the pollinating insects are under pressure. Their numbers and diversity have declined dramatically in recent decades, the Commission writes. “Many species are on the brink of extinction.”

Koos Biesmeijer of Naturalis shows which species have disappeared and what the consequences are:

These bees disappeared from the Netherlands: ‘I’m worried, yes’

Research institutes from several EU member states are now setting up a network in which volunteers and professionals monitor how the numbers of wild bees, butterflies, hoverflies and moths are developing. They do this regularly, over a longer period of time and all in the same way.

Into the field

Such structural monitoring is still lacking, says bee expert Koos Biesmeijer. He is scientific director of Naturalis and one of the drivers of the project. “For example, our knowledge comes from people who like bees and go to different places to see special species. Scientists also do research, but their projects usually only last a few years.”

“The knowledge is therefore fragmented and we hardly have any information from large parts of Europe,” says Biesmeijer. “The puzzle pieces we did show that things are going badly, but the picture is incomplete.”

The new measuring network must be in place in 2026. Volunteers are already going into the field to find out what works in practice. Ultimately, there should be at least 2000 monitoring locations in Europe, in urban, rural and nature areas. The network is part of the ‘New Deal’ for pollinators.

Good weather necessary for counting

Eleven volunteers are now active for the new network in the Netherlands, at five locations: from the Amsterdamse Waterleidingduinen to the Alblasserwaard. From April to September, they count and catch insects for one day each month in their ‘own’ research area of ​​one square kilometre. They follow training to be able to do this well.

The weather has to be good for a field day, says project employee Merel Bozua. “Little wind, little rain, at least 13 degrees and preferably a sun, otherwise the flying creatures will hide.”

The volunteers slowly walk a 500-meter stretch through their area several times. They keep counting how many specimens they see of, for example, different bee groups such as the robust large bees, small bees and ‘honey bees’. Or from hoverfly groups such as the yellow-spotted/striped hoverflies and the bumblebee-like hoverflies, says Bozua.

Hairy paws

Because there are more than 300 species of hoverfly in the Netherlands and a comparable number of species of wild bees, it is often impossible to determine with the naked eye what exactly is flying by. That is why the volunteers also catch insects in jars with water and soapy water. Naturalis experts put them under the microscope and determine which species it is. For example, by looking at the hair on the legs and the shape of the abdomen.

Volunteers at work in the Amsterdamse Waterleidingduinen:

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Volunteers count pollinators in the water supply dunes

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The insects are lured with these traps

“This is a great initiative that will show how the different groups of pollinators are doing,” says professor of plant ecology and nature management David Kleijn of Wageningen University. “The only sad thing is that this project won’t tell us how all those hundreds of individual species are doing. That’s not feasible due to the rarity of most species.”

Garden full of flowers

Biesmeijer acknowledges that the measurement network mainly maps global trends: how the total numbers change over time and how large or small the species richness is. He also calls the monitoring network necessary to assess the effect of protective measures such as changes in nature or agricultural policy.

There are already rules of thumb about what helps. “What those insects need is a healthy living environment, food and a place to reproduce,” says Biesmeijer. “Bees are now having a hard time, for example, because there are fewer flowers and nesting places in hedges, ditch edges and roadsides than before due to intensive land use.”

Sowing more flowers in gardens and on balconies helps a bit, but doesn’t solve the problem, he says. “The species that need protection largely live in nature reserves, in open areas and on grasslands. More attractive gardens help about twenty common species that live there. Many bees on the red list have no use for that.”

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