Battling the boar: Researcher develops method to assess crop damage
A biologist at Antwerp University has developed a model to assess how much damage is being done to crops in Flanders by wild boar
But for Anneleen Rutten, there’s a lot more to wild animals then how they’re served on a plate. A researcher at Antwerp University and the forest and nature research institute Inbo, she has been studying the habits of the wild boar in Flanders for years.
A biologist, Rutten takes a special interest in local biodiversity. “I am interested in large mammals and human-wildlife conflicts,” she explains. “The wild boar disappeared from Flanders following the Second World War, but it made a comeback in the region starting in 2006. Now it’s becoming the focus of a significant conflict.”
For her current PhD research, Rutten has developed a system to measure the amount of damage the animals inflict on farmers’ fields – particularly corn fields. Her previous work brought her into contact with the agricultural sector in Flanders, and the boar problem was readily apparent.
Since the boar was previously absent from Flanders, “damage inflicted by it isn’t monitored here,” she says.
Wallonia doesn’t have the same problem because the boar has always roamed its forests – and fields. In that region, there is a system whereby experts assess boar-inflicted damage to fields, and the farmers can then file insurance claims.
But in Flanders, says Rutten, “there is no system for compensating farmers whose fields are damaged by boar”.
The method she has developed, however, could lead to proper assessments and compensation. She uses a drone to fly over fields and photograph them. Then she fuses all the photographs together so she has an image of the entire field.
The females roll around and bring the corn stalks down to the ground so the piglets can get at them
Damage to the field is then highlighted with certain colours. The model uses two programmes and a code she wrote herself. She also had to “teach” the programme how to recognised damage in a field.
The boar’s effect on fields goes beyond eating a few ears of corn. Piglets, it seems, cannot reach the corn, “so the females roll around in the field and bring the corn stalks down to the ground,” explains Rutten. “So they’re destroying the entire stalk.”
Rutten has evidence of huge swaths of corn fields completely destroyed by wild boar. The animals also root around in grasslands, but they are mostly looking for earthworms, so the damage is more limited than in corn fields.
Neutral information ‘crucial’
Flemish farmers’ union Boerenbond, as well as authorities in Wallonia, have shown interest in Rutten’s new damage-assessment model. “I think it’s important to have neutral, scientific information to work with,” she says. “What will happen with my results – that’s politics. But it’s crucial that there are figures in terms of how much damage there is.”
Farmers, she continues, have tried preventive measures to keep the boar out. Electric fences, she says, are the most obvious resource, but government regulations suggest that the lowest wire be at least 20 centimetres above the ground.
Wild boars are really smart, and they quickly learn that there’s no real danger
“A piglet can get under that,” she says. “And if they do that, the females will follow them whether they get an electric shock or not. Then they are hesitant to lead their piglets out of the field because of the shock they know they’re going to get. So it actually can keep them in the field longer.”
Farmers have also experimented with loud noises and certain smells to keep the animals out of their fields. “But these usually only work temporarily because wild boars are really smart, and they quickly learn that there’s no real danger.”
Now that the first part of Rutten’s PhD research is complete, she’s moving on to the second challenge: Why boars prey on specific fields. “Sometimes you see three or four adjacent fields of corn, and in one or two fields, you find a lot of damage, while in the others there’s hardly any. It could be about the kind of corn being grown or the fertiliser being used. I’m working on models to see how these factors influence the boars’ behaviour.”
Photo top: The infamous wild boar
Above: a field that has been visited by a group of boar
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