Exotic species sometimes unfairly hated: ‘They can be good for our nature’

A lot of people will recognize them: in recent years you’ve often seen ring-necked parrots flying overhead and screaming. This green parrot is an example of the many exotic species that have settled in our country.

Aliens are animals, plants, fungi, or microorganisms that humans have introduced—accidentally or intentionally—outside their native habitat. Exotics are not usually popular, and sometimes even hated. This is due to the unpleasant consequences that the presence of this species can have on the local flora and fauna.

Baudewijn Odé, researcher at Floristiek Onderzoek Nederland, (FLORON) is an advocate for combating alien species that are expanding in our country and that have a significant negative impact on local biodiversity. “Because some exotic species have no natural enemies in the Netherlands, they can easily become invasive and occupy the space and food of native species, putting them at a disadvantage,” he says.

Useful exotic items

However, other experts think otherwise. David Thiltges, a marine ecologist and professor at the Royal Netherlands Institute for Marine Research, NIOZ, also sees the benefits of some exotic species. “The stranger must not always die,” he says.

Lisbeth Bakker and Wim van der Putten, researchers at the Netherlands Institute for the Environment (NIOO-KNAW), agree. “Some exotics can be beneficial to the habitat they settle in,” says Packer, who studies freshwater plants.

Van der Putten, a wild plant researcher, sees the damage some exotic species do, but he also believes that in the long run, certain alien species It can be integrated into the original nature. He speaks of short-term “evolution”: “Over time, local insects, fungi, and bacteria adapt to take advantage of the exotic. In this way the exotic becomes less invasive and is eventually naturalized.” Thus the stranger is included in the native ecosystem.

Examples

According to the scientists, the exotic species described below make a positive contribution to nature in the Netherlands.

1. Pacific oysters

This huge type of oyster was brought to the Netherlands for consumption. It was believed that this shellfish could not breed in the cold waters of the North Sea and the Wadden Sea. Large reefs of these exotic shellfish are now found in both the Wadden Sea and the Delta.

“At first, biologists were afraid that this species would drive out the native oysters, but that didn’t happen. No native oysters disappeared,” Thiltjes says. “Oyster reefs became the basis for the creation of new mussels. You find protection in such reefs against crabs, for example.”

2. Triangle mussels

This exotic species is found naturally in the basins around the Black Sea and the Caspian Sea. Oysters have a positive effect on aquatic plants, says Packer. “They filter algae out of the water as their food, which makes the water clearer and allows sunlight to shine more through the water. This benefits aquatic plants that need light,” says Packer. “These mussels are also food for waterfowl, such as diving ducks.”

3. Bunny

Rabbits are now seen as a native species, but rabbits were originally brought to the Netherlands from the Iberian Peninsula. Packer says rabbits are now very important to dune areas. “By eating the grass, the rabbits prevent weeds from growing in the dunes.”

4. Giant Hogweed

This species of the so-called screen flower family was brought to the Netherlands to thrive in gardens. It is now an invasive species that is rapidly expanding in our regions. Since this plant is nearly impossible to eradicate everywhere, Van der Putten believes we should look at these exotics in a different way, by focusing on the possibilities of controlling plants using soil diseases and pests. “This plant has very large display flowers, which many insects, such as bees, bumblebees, and hoverflies, can benefit from, so they also do a good job.”