Global trade and transport, both overland and via oceans, is contributing to the unintended spread of species across the globe. In other cases, species have been introduced on purpose. These non-native species are known as invasive species. Globally, invasive species are the second-biggest threat to biodiversity after habitat destruction. There are fewer known invasive species in the Arctic than further south. However, any increase in shipping activity is a major concern for their introduction. Coordinated national and international action is needed to limit the spread of invasive species.