The Bureau for Risk Assessment & Research (BuRO) commissioned a study on the presence and effects of the invasive ant species at the Waalsdorpervlakte. This exotic ant species originates from Central Asia. The supercolony at Waalsdorpervlakte is the first colony of invasive ants observed in a nature reserve in Northwestern Europe. It is known that invasive ants can cause damage and nuisance in urban areas. The effects on nature in the Netherlands have not been previously investigated.
The research at Waalsdorpervlakte was conducted in 2024 by the drinking water company and nature manager Dunea and by the EIS Knowledge Centre for Insects. The research shows that the invasive ant species may have effects on other ant species. It also appears that the invasive ant causes sunken roads and nuisance in buildings. Based on these research results and the limited options for removing a supercolony of ants, it is important to prevent further spread of the invasive ant through the transport of soil, construction materials, and green waste. BuRO advises the director of Nature from Agriculture, Fisheries, Food Security, and Nature to inform groups transporting soil, construction materials, and green waste about the risks of hitchhiking ants.
Supercolony of Invasive Ants is at least Five Football Fields Large at Waalsdorpervlakte
The invasive ant forms so-called supercolonies: colonies with multiple queens and nests that are socially connected. At Waalsdorpervlakte, the supercolony covers an area of at least 3.4 hectares, comparable to at least five football fields. This area is on the edge of urban The Hague and is part of the Natura 2000 area Meijendel & Berkheide. It is also used as a water extraction area.
Research Provides First Indication of Effect of Invasive Ants on Dutch Nature
A supercolony of invasive ants can influence the food web in nature due to the large number of workers. Examples from the literature indicate a negative effect on other ant species, a positive effect on aphids, and a varying effect on soil organisms. At Waalsdorpervlakte, fewer ant species were observed as the density of invasive ants was higher. The total number of aphids did not differ inside and outside the ant colony, but within the colony, more aphids were parasitized by aphid wasps.
Invasive Ants Cause Sunken Paths and Nuisance in Buildings
At various locations near Waalsdorpervlakte, paths have sunk due to the digging work of invasive ants. They were also in an office building, where employees regularly experienced nuisance from the ants. The likelihood of damage to electrical systems seems low, as the invasive ants at this location showed no preference for electrical devices. At the water extraction facility in the nature reserve, the invasive ants had no effect, as they minimally disturbed the soil and the nests were not deeper than 40 cm.
Documents
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Cover letter for the research on invasive ant species at Waalsdorpervlakte
The Bureau for Risk Assessment & Research (BuRO) commissioned a study on the presence and effects of the invasive ...
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Spread and Effects of Invasive Ants at Waalsdorpervlakte
This report provides an overview of the presence and possible effects of a supercolony of invasive ants at Waalsdorpervlakte. ...