Invasive Alien Species

Use the VIRTUE method to search for invasive alien species!

This section is currently under development and more material will be added.

What is an invasive alien species?

Species naturally spread across the Earth, for example by swimming, flying or walking. But when we humans help different species to move across the Earth, consciously or unconsciously and often over longer distances, these species are called alien species in the new area to which they have been moved. An alien species that affects, or has the ability to affect, local biodiversity, or us humans negatively is called an invasive alien species.

There is a difference between a species that has spread naturally and an invasive alien species that we humans have moved. There is also a difference between invasive alien species and the native species that are already naturally present in the area.

Why are invasive alien species a threat to the Earth's biodiversity?

Some of the alien species we humans move will, for various reasons, manage to survive and reproduce in the new area. And if the new invasive alien species can compete with the native species for food, or hunt them as prey, the invasive alien species can cause the native species to decline in numbers. The invasive alien species can also bring with them parasites and diseases that can infect the native species.

Invasive alien species can also negatively affect us humans by eradicating native species that we humans depend on or by bringing with them diseases that can affect us.

 

The film shows the species American blue crab (with the scientific name Callinectes sapidus). The American blue crab is naturally found on the North American east coast. The species has been moved by humans to, for example, the Spanish Mediterranean coast and the Adriatic Sea where it has become an invasive alien species. The blue crab eats many different marine native species and has had a major impact on biodiversity in areas where it has been introduced. The local fishing industry is also negatively affected when blue crabs, for example, eat farmed mussels. However, we will not find any blucrabs on the VIRTUE racks.

Why is it important to limit the spread of invasive alien species?

Research shows that the problem of invasive alien species will increase in the future as our transport across the earth increases. The ongoing climate change also reinforces the negative impact of invasive alien species as more species can survive in new areas as temperatures increase.

Why is it important to monitor and detect invasive species early?

Research also shows that it can be very difficult to combat an invasive alien species that has managed to establish itself in a new area. This is not least the case for marine invasive alien species that often spread with larval stages at the beginning of their life cycle. Therefore, early detection and early response are very important when it comes to combating invasive alien species.

You can help detect and report invasive alien species in the BiodivOcean project!

By participating in the BiodivOcean project, you can help research and the authorities detect and report invasive alien species. By hanging so-called VIRTUE racks in the sea that you then pick up and examine, you could be the first to discover and report a new invasive alien species.

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