The birds and the bees; spring fever at Anna’s Tuin en Ruigte
The temperatures are rising, the pollen is floating through the air and the trees are turning green. In short: it’s spring, and that means it’s time for the national bee count again. At Anna’s Tuin en Ruigte, the tucked-away nature reserve full of vegetable gardens and food forests next to the Science Park that is financially supported by the UvA, nature lovers are also busy with the buzzing insects.
The sun is shining, the birds are singing, new green shoots are appearing on every branch and the scent of spring is in the air. Today’s conditions are therefore perfect for contributing to the annual bee monitor, which was set up to map the bee population in our country. From 10 to 14 April, every Dutch citizen is asked to spend half an hour noting down every bee, bumblebee, wasp or hoverfly that flies by. For Bodhi Soederhuizen (23), a biology student at the UvA and bee fanatic extraordinaire, this is all in a day’s work. “I’m chronically counting bees,” he says, as he strolls through Anna’s Tuin en Ruigte with his net at the ready.
Recognising
“When I have class here at Science Park, I often come a little early on purpose so that I can take a walk through Anna’s Tuin first. Then I can see what’s flying around that day,” Soederhuizen says. Esther Krop (51), garden coordinator and volunteer at Anna’s Tuin en Ruigte, is also a fan. “Our group here often tries to participate in the annual count because we think it is very important that it happens. Fortunately, you get a map with the most common species, otherwise recognising them can be a problem.”
Soederhuizen adds: “Although some species are easily recognisable, for others you can only tell the difference under a microscope. There are about 69 different species of bees flying around in the garden here, so it’s difficult to recognise them all. The most common are the red mason bee and the horned mason bee, but there are also a lot of bumblebees flying around here. In the end, it is mainly about monitoring the population, identifying the different species is less important.”
Extinction
How many bees an amateur counter can count in half an hour depends on the weather conditions, Krop explains. “On Saturday it will be twenty degrees, perfect weather for the bees, so I expect this to be a good year.” Soederhuizen nods in agreement and takes a glass jar out of his pocket, in which a sturdy garden bumblebee is buzzing around. “I just caught this one here in the garden, even though you see them increasingly less often. This species is showing a strong downward trend, which means they could become extinct by the end of this century, but I still see them flying around here sometimes. That is what makes Anna’s Garden so special.” He opens the jar and the bumblebee flies away.
Soederhuizen emphasises the importance of the bee monitor. “The bees are really not doing well, so it is important to be able to quantify that properly. In order to monitor bees structurally, you have to measure the population at a fixed time every year. We only know that a species like the garden bumblebee is threatened with extinction because we carry out measurements like this. This gives us a really good picture.”
Dramatic
And that picture is worrying, says Krop. “It’s really dramatic. If the bee population collapses, we won’t survive either. We’ll be really screwed. Most people do not realise how dependent we are on bees. They pollinate the plants, which then bear fruit and bloom. There are a few other insects that do the same, so bees are truly crucial. Plants and bees cannot live without each other.”
And this while the insect population has shrunk drastically in recent years, Soederhuizen continues. “Long-term research in Germany has shown that the total biomass of insects has decreased by more than seventy percent in the past thirty years. But you also hear it a lot anecdotally. People in their fifties regularly say that they used to be able to see the entire windscreen of the car covered in insects after a drive, but that is no longer the case.”
Bee hotels
That is why all kinds of things are happening at Anna’s Tuin en Ruigte to support the bee population. For example, there is a bee hotel, full of stalks in which the bees can lay their eggs, and you will find a loam sand hill that creates a microclimate for the bees. “But a hotel alone is not enough, of course there must be enough food too,” Krop explains. “The planting of wild, native flowers and plants is very important. We also provide a blossom arch, which means that we have flowering plants almost all year round, there really must always be food to be found.”
She is abruptly interrupted by Soederhuizen. “Look, there’s another one. A horned mason bee,” the biology student calls out enthusiastically. “Because of the wide variety of bees flying around here, it’s important to have many different flowers.” He bends down and points to an elongated flower. “This is ground-ivy, a fairly long flower. Many bees are too small for this, but the tongue of a bumblebee is long enough to reach the flower, so they are very attracted to it. That is why this diversity of flowers is so essential.”
Bodhi Soederhuizen spent a year researching all the different bees and wasps that can be found in Anna’s Tuin en Ruigte. On 15 May, he will give a lecture on the subject at Sustainalab, after which there will be a walk through the garden, during which insects will be caught and identified.
Organic
Krop has a few tips for the passionate amateur who has become as enthusiastic as she is after a weekend of bee counting. “You can do a lot even just on your balcony. Oregano, mint and cowslip, for example, are very good for bees, but you have to be careful with flowers from garden centres. The pesticides they contain can be deadly for bees, so you really should only use organic plants. Otherwise you’ll only be killing them off.”
After walking around for a while and chatting away, Soederhuizen glances at his watch. Half an hour has passed and although he has not been paying close attention while talking, he is a pro at counting bees. “Out of the corner of my eye, I think I’ve seen about twenty, but later in the day it will probably be teeming with bees.” His appeal is therefore: “On Saturday, go outside and count the bees.”
