‘Alien’ invaders introduced by humans could kill off native wildlife, study finds
FOREIGN invaders could kill off our native wildlife, a new study has warned.
Researchers say that invasive “alien” species – such as Canada Geese or non-native plants – may cause catastrophic damage to our birds, animals, plants and trees.
They have calculated that an increase of 20 to 30 per cent of invasive non-native species would lead to “dramatic” future biodiversity loss worldwide.
The worrying finding is the conclusion of a study by a global team of researchers led by Dr Franz Essl and Dr Bernd Lenzner of the University of Vienna in Austria.
The study, published in the journal Global Change Biology, shows human activities, both intentionally and unintentionally, introduce more and more plant and animal species to new regions of the world – for example, via tourism.
Some of the alien species have negative consequences for biodiversity and human wellbeing, such as by displacing native species or transmitting diseases.
Canada geese are now well established in Europe, posing a serious threat to biodiversity.
They also damage farmland and have been involved in a number of bird strikes.
However, while there is relatively good information on the historical spread of alien species, the researchers said there is still little knowledge about their future development.
Dr Essl said: “At the moment it is not yet possible to generate precise predictions based on computer models as to how the spread and impact of alien species will change in the future. Therefore, expert assessments via standardised surveys are an important tool to obtain a better understanding of the causes and consequences of the spread and impact of alien species for the coming decades.”
The study shows that an increase of 20% to 30% in the number of newly introduced alien species is considered sufficient to cause “massive” global biodiversity loss.
Dr Essl said that value is likely to be reached soon, as the number of introduced species is constantly increasing.
He explained that humans are the “main driver” of the future spread of alien species.
The experts identified three main reasons, primarily the increasing global transport of goods, followed by climate change and then the impacts of economic development such as energy consumption and land use.
The study also shows that the spread of alien species can be greatly slowed down by ambitious countermeasures.
The researchers also investigated the influence of the increase of alien species on different regions of the world.
They found that tourism is a major driver of biological invasions in tropical and subtropical regions, while climate change favours the survival and establishment of alien species in the future, especially in polar and temperate regions.