Introduction

What is an invasive alien species?

Alien species are plants, animals and other organisms that spread from their original environment through human activities to new environments. The species can then be established in the new environment and create serious problems for ecosystems, infrastructure or human health and is then defined as an invasive alien species (IAS). IAS are one of the biggest threats to biodiversity.

How do IAS spread?

IAS in marine environments can spread through commercial shipping in ballast water, on ship hulls or in sea chests in ships. An important reason why invasive alien species continue to spread throughout the world is the increasing global trade, with more and faster transport. But there are more routes of spread, for example commercial shipping and recreational boats, aquaculture and aquariums. Organisms can travel long distances in the ballast waters in ships or attached to ship hulls or in sea chests.

IAS and climate change

The spreading of IAS is increasing due to climate change. Species that require warmer water temperatures can survive in environments further north as the water temperatures increase. Climate change also leads to new trade routes opening up in the north. As the ice is melting in the Arctic region, ships can navigate through this emerging passage, reducing the distance between the Pacific and the Atlantic ocean. Consequently, this will lead to an increased shipping traffic between the Pacific and the Atlantic, and eventually to the Nordic sea.

Photo: Henrik Glenner showing some of the team members an IAS.