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 (IPBS).
It revealed that 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.
Approved last week in Bonn, Germany, by representatives of the 143 member States of IPBES, 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 yearly 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 Prof. Helen Roy (United Kingdom), co-chair of the Assessment with Prof. Anibal Pauchard and Prof. Peter Stoett.
The authors 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 per cent of alien plants; 22 per cent of alien invertebrates; 14 per cent of alien vertebrates; and 11 per cent 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.
While many alien species were historically introduced on purpose for their perceived benefits to people, the IPBES report finds that the negative impacts of those that do become invasive are enormous for nature and people. “Invasive alien species have been a major factor in 60 per cent and the only driver in 16 per cent of global animal and plant extinctions that we have recorded, and at least 218 invasive alien species have been responsible for more than 1,200 local extinctions.
The report indicates that eradication of alien plants is more challenging due to the length of time that seeds may lie dormant in soil. The authors add that successful eradication programmes depend on, amongst other elements, the support and engagement of stakeholders and Indigenous Peoples and local communities.
“One of the most important messages from the report is that ambitious progress in tackling invasive alien species is achievable,” said Stoett. “What is needed is a context-specific integrated approach, across and within countries and the various sectors involved in providing biosecurity, including trade and transportation; human and plant health; economic development and more. This will have far-reaching benefits for nature and people.”
Options explored in the report include considering coherent policies and codes of conduct across sectors and scales; commitment and resourcing; public awareness and engagement, such as citizen science campaigns like those promoting ‘check, clean and dry’; open and interoperable information systems; filling knowledge gaps (the authors identify more than 40 areas where research is needed); as well as inclusive and fair governance.
“The immediate urgency of invasive alien species, with extensive and growing harm to nature and people, makes this report so valuable and timely,” said the Executive Secretary of IPBES, Dr. Anne Larigauderie. “The Governments of the world agreed, in December last year, as part of the new Kunming-Montreal Global Biodiversity Framework, to reduce the introduction and establishment of priority invasive alien species by at least 50 per cent by 2030. This is a vital, but also very ambitious commitment. The IPBES Invasive Alien Species Report provides the evidence, tools and options to help make this commitment more achievable.”
