Invasive alien species on the rise worldwide

Invasive alien species are on the rise worldwide and their numbers show no sign of slowing down despite global efforts to address the challenge, according to a study published in Nature Communications by an international team of researchers, including members of the IUCN Species Survival Commission (SSC) Invasive Species Specialist Group.  

Asian common toad (Duttaphrynus melanostictus), Viet Nam Photo: Peter Nijenhuls Flickr CC BY NC ND 2.0

The study found that during the last 200 years, the number of new invasive species introductions has continuously increased worldwide, with more than a third of all first introductions recorded between 1970 and 2014. It also found that more new invasions are expected among all groups of species in the near future, with the exception of mammals and fishes.

“The results of this study are alarming, because we see a constant increase in the number of new invasions in all taxonomic groups and in all regions of the world,“ says Piero Genovesi, Chair of the IUCN SSC Invasive Species Specialist Group, and one of the authors of the report. “These invasions can have negative impacts on ecosystems, leading to biodiversity loss and the extinction of native plants and animals. This, in turn, can have potentially devastating consequences on the food, medicines, clean water and other benefits that nature provides, making it more challenging for the global community to meet the UN’s Sustainable Development Goals.”

Drawing on new data including the IUCN Global Invasive Species Database and the Global Register of Introduced and Invasive Species, the authors analysed more than 45,000 first records of almost 17,000 established alien species. The results indicate a distinct increase in first records of invasive vascular plants in the 19th century, probably as a result of the intensification of horticulture. The rates of new introductions of other organisms such as algae, molluscs or insects increased steeply after 1950, most likely as a consequence of the growth of global trade.

Despite the increasing number of international agreements and legislation in place to address the problem, the growing number of invasive species introductions worldwide highlights the urgent need for more effective prevention policies, according to the authors.

Invasive alien species are species introduced by humans, accidentally or intentionally, outside their native range and have negative impacts upon native biodiversity, ecosystem services, or human wellbeing. They are a major driver of biodiversity loss, and the most common threat responsible for extinctions of amphibians, reptiles and mammals.

At the IUCN World Conservation Congress in Hawai′i, IUCN – together with 32 organisations and institutions – launched the Honolulu Challenge on Invasive Alien Species. This global initiative calls for urgent action to reduce the impacts of invasive alien species. By the end of 2016, the Challenge had 34 supporters and seven commitments, including two from national governments: New Zealand and the UK.

The study, ‘No saturation in the accumulation of alien species worldwide’ can be accessed here

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