It would seem logical: more geese eat more grass, leaving less for the farmer to harvest. But a recent study suggests it may not be so straightforward. An international team led by the Netherlands Institute of Ecology (NIOO-KNAW) looked at the impact of different goose species and the number of geese on agricultural damage. Their first conclusion: “The number of geese does not translate directly to a smaller grass yield.”

Large numbers of geese graze on agricultural grassland, where they eat grass meant for cattle. Geese are migratory birds, so they’re not stopped by borders. Around 2.4 million geese now winter in the Netherlands each year. One third stays in a single part of the country: the province of Friesland (Fryslân). This includes more than half a million barnacle geese alone.

Not everyone sees the geese as welcome guests, on account of the feared agricultural damage. Goose populations have skyrocketed over the past few decades, and conflict between geese and agriculture has intensified accordingly. Different methods can be used to control the geese, including shooting at them. But to justify this, it’s important to know how goose abundance and interactions between species affect the amount of damage.

“Fewer geese doesn’t automatically mean less damage,” says animal ecologist Nelleke Buitendijk from NIOO-KNAW. It’s one of the most striking conclusions of a scientific study by Buitendijk and her colleagues – the first in a series of three – that was recently published in the Journal of Applied Ecology.

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