Invasive alien species: Can Europe win the battle?

Invasive alien species (IAS) are one of the main causes of biodiversity loss. In Europe, there are over 6,000 exotic terrestrial plants, more than 4,000 non-native terrestrial animals, and over a thousand exotic marine species.

Some of these species not only threaten nature but also pose risks to human health and the European economy. The Asian hornet and the Rugulopteryx Okamurae algae are among the most concerning.

Why are these a growing concern?

The Vespa velutina, commonly known as the Asian hornet, is believed to have arrived in southwestern France via a shipment of pottery from Shanghai. It has since spread across the country, expanded into neighbouring nations, and was recently detected in Hungary and Slovakia. 

It is estimated that a colony of Asian hornets consumes 11 kg of insects per year. In France, the species is responsible for a significant proportion of honeybee deaths, causing huge losses for the beekeepers. Asian hornet stings also result in a few fatalities each year.

Invasive species are also affecting aquatic ecosystems. Rugulopteryx Okamurae, a type of underwater algae, is also believed to have been transported from Asia on cargo ships. First detected near the Straits of Gibraltar less than ten years ago, it has since spread to various Mediterranean locations such as Barcelona, Marseille, and Palermo, as well as to the Adriatic Sea and the Basque Country.

Scientists are astonished by this algae’s rapid growth in such diverse environments. In Andalusia, it often carpets the seabed, and its dominance is a major factor in the loss of biodiversity.

While not toxic to humans, this algae poses significant issues to the tourism and fishing industries. Each summer, millions of euros are spent cleaning beaches in Andalusia, and fishermen’s nets often fill with algae. A decline in fish catch has also been observed in the fishing zones where it proliferates.

What is the European Union doing to fight back?

In 2015, the European Union adopted a regulation on invasive alien species. 88 species – 41 plants and 47 animals – are currently listed as IAS of Union concern, leading to measures to prevent their introduction, containing their spread, and imposing trade bans.

There are successful examples of invasive alien species eradication on small islands, such as the Asian hornet on Mallorca. Although eradication can be more challenging in larger areas, it is also possible. For instance, the Pallas squirrel has been successfully eradicated from Belgium and the Netherlands.

Experts agree that preventing the entry of invasive species into the EU is the cheapest and most efficient control method. In cases of introduction, early detection and rapid eradication are the priorities. Managing invasive alien species is estimated to be ten times less expensive than dealing with the damage they cause.