The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) has published the results of its four-year Assessment on Invasive Alien Species and their Control.
Key findings
Invasive Alien Species pose major global threats to nature, economies, food security and human health
- Key Role in 60% of Global Plant & Animal Extinctions
- Annual Costs Now >$423 Billion – Have Quadrupled Every Decade Since 1970
- Report Provides Evidence, Tools & Options to Help Governments Achieve Ambitious New Global Goal on Invasive Alien Species
The severe global threat posed by invasive alien species is underappreciated, underestimated, and often unacknowledged. According to a major new report by the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES), more than 37,000 alien species have been introduced by many human activities to regions and biomes around the world. This conservative estimate is now rising at unprecedented rates. More than 3,500 of these are harmful invasive alien species – seriously threatening nature, nature’s contributions to people and good quality of life. Too often ignored until it is too late, invasive alien species are a significant challenge to people in all regions and in every country.
The Assessment Report on Invasive Alien Species and their Control finds that alongside dramatic changes to biodiversity and ecosystems, the global economic cost of invasive alien species exceeded $423 billion annually in 2019, with costs having at least quadrupled every decade since 1970.
In 2019, the IPBES Global Assessment Report found that invasive alien species are one of the five most important direct drivers of biodiversity loss – alongside changes in land- and sea-use, direct exploitation of species, climate change and pollution. On the basis of this finding, Governments tasked IPBES to provide the best available evidence and policy options to deal with the challenges of biological invasions. The resulting report was produced by 86 experts from 49 countries, working for more than four and a half years. It draws on more than 13,000 references, including very significant contributions from Indigenous Peoples and local communities, making it the most comprehensive assessment ever carried out of invasive alien species around the world.
“Invasive alien species are a major threat to biodiversity and can cause irreversible damage to nature, including local and global species extinctions, and also threaten human wellbeing,” said Professor Helen Roy (United Kingdom), co-chair of the Assessment with Prof. Anibal Pauchard (Chile) and Prof. Peter Stoett (Canada).
The authors of the report emphasise that not all alien species become invasive – invasive alien species are the subset of alien species that are known to have become established and spread, which cause negative impacts on nature and often also on people. About 6% of alien plants; 22% of alien invertebrates; 14% of alien vertebrates; and 11% of alien microbes are known to be invasive, posing major risks to nature and to people. People with the greatest direct dependence on nature, such as Indigenous Peoples and local communities, are found to be at even greater risk. More than 2,300 invasive alien species are found on lands under the stewardship of Indigenous Peoples – threatening their quality of life and even cultural identities.
Where are the greatest impacts reported?
The report shows that 34% of the impacts of biological invasions were reported from the Americas, 31% from Europe and Central Asia, 25% from Asia and the Pacific and about 7% from Africa. Most negative impacts are reported on land (about 75%) – especially in forests, woodlands and cultivated areas – with considerably fewer reported in freshwater (14%) and marine (10%) habitats . Invasive alien species are most damaging on islands, with numbers of alien plants now exceeding the number of native plants on more than 25% of all islands.
“The future threat from invasive alien species is a major concern,” said Prof. Roy. “37% of the 37,000 alien species known today have been reported since 1970 – largely caused by rising levels of global trade and human travel. Under ‘business-as-usual’ conditions, we project that total numbers of alien species will continue to increase in this way.”
What action can be taken?
On a more positive note, the report highlights that future biological invasions, invasive alien species, and their impacts, can be prevented through effective management and more integrated approaches.
“The good news is that, for almost every context and situation, there are management tools, governance options and targeted actions that really work,” said Prof. Pauchard. “Prevention is absolutely the best, most cost-effective option – but eradication, containment and control are also effective in specific contexts. Ecosystem restoration can also improve the results of management actions and increase the resistance of ecosystems to future invasive alien species . Indeed, managing invasive alien species can help to mitigate the negative effects of other drivers of change.”