Bordeaux’s growers are encouraging bats to roost in their vineyards, seeing the animals as allies in the war against pests.
“Two years ago we engaged with the Bird Protection League and on their suggestion measured the bat population,” said Allan Sichel, head of Bordeaux's Wine Bureau Conseil Interprofessionnel du Vin de Bordeaux (CIVB). Sichel said the study was done across 20 different chateaux and included 23 plots of vines. “In France, there are 33 species of bats, of which 20 are present in the Gironde.”
The study revealed that the flying rodents devour Eudemis and Cochlylis moths, pests that feed on grapes. “We realised the bats feed on these moths, and quite significantly,” said Sichel. “Each bat will eat about 2,000 of these moths a night, so are very useful in regulating the moth population. Therefore, if we had more bats, we’d be using less pesticides.”
Unfortunately, bats have always had a poor reputation, said Sichel. “A lot of people were scared of bats, saying they pull your hair out.” So the first order of business was to reassure growers that “bats are allies. When you have bats, it’s a good thing.”
Bats are mostly present during the summer period, “but we want the bat population to stay in place to ensure they’re there next year”. Growers are now encouraged to leave dead trees or old huts in place, to preserve bat habitats. Some estates have gone so far as to install bat houses, while others leave grassy strips unmown, so the bats find it easier to enter vine rows.
The CIVB has also set up an online bat observatory, both to help growers identify the presence of bats and in turn contribute information about bat habitats. “What we’d like them to do is give us feedback on this internet site, to say ‘I’ve got bats here and this is what I’ve done’.”
The bat project is only part of the CIVB’s work on sustainability. Another work in progress is encouraging the presence of pollinators, on which the CIVB will host a major conference in June. “The basic message we’re telling everyone is that insects are important,” said Sichel.
Keeping grass cover between rows is one way to attract pollinators. Growers are also encouraged to plant hedgerows where they can. “We have a partnership with a hunters’ association, and they’ll come and help plant the plants to create hedgerows,” says Sichel, adding that such projects are cheap and useful and so don’t take much to persuade people to get involved. Nearly 23 km of shrub hedges had been planted by the end of 2018, thanks to the help of Arbres et Paysages, a non-profit organisation.
“People are going further, and planting trees in the middle of a vine plot. It’s more difficult to get the tractors in, but it benefits biodiversity and brings insects and birds back.” Sichel said trees also help to regulate micoorganisms in the soil. “It will take 10 or 15 years before the trees are big enough to have any sort of effect, but it just shows that people are taking these biodiversity messages on board.”