Invasive plant and animal species that have been relocated from their original habitats due to human actions are causing massive economic impacts and immeasurable environmental repercussions across the globe, the world biodiversity body said in its first extensive review.
More than 3,500 of at least 37,000 alien species introduced by human activities are harmful and invasive, seriously threatening nature, with climate change exacerbating the issue, according to the assessment report released Monday by the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES).
The U.N.-based assessment said 25% of the impacts of biological invasions were reported from Asia and the Pacific, compared to 34% from the Americas and 31% from Europe and Central Asia.
“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, a co-chair of the assessment team.
According to the report, the failure to tackle the issue costs the world U.S. $423 billion a year, with costs having at least quadrupled every decade since 1970 in damages and lost income. The amount is more than the GDP of Vietnam.
The report’s authors told a press conference on Monday that all the figures, including the number of invasive alien species and the estimated damage, are gross underestimations.
The South American water hyacinth, one of the quickest-growing plants that impacts freshwater fishing, including in large swathes of Asia, tops the list as the most prevalent invasive species.
The golden apple snail, another species native to South America, has become invasive in Southeast Asia, posing threats to agriculture, especially rice paddies since the 1980s.
In China, the red imported fire ant has been a problematic invasive species since at least 2003, impacting plants, animals, and agriculture, while giant African snails have destroyed vegetables in southern China.
There are already more than 660 invasive alien species in China, including 71 that have threatened or could threaten the country’s natural ecosystems, the South China Morning Post reported in July, quoting the Ministry of Ecology and Environment.
Harmful introduced species among top five for biodiversity decline
The IPBES report, prepared by 86 experts from 49 countries over four years, found invasive alien species played a key role in 60% of global plant and animal extinctions and were solely responsible for 16% of the extinctions recorded.
The author said 218 invasive alien species caused 1,215 local extinctions of native species.
According to IPBES, invasive foreign species rank among the top five primary causes of biodiversity decline, alongside land- and sea-use changes, direct species exploitation, climate change, and pollution.
About three-quarters of the negative impacts are reported on land, especially in forests, woodlands, and cultivated areas, with considerably fewer reported in freshwater (14%) and marine (10%) habitats.
Alien invasive species cause the most harm on islands, where the count of non-native plants on over 25% of them now surpasses that of native ones.
About 200 alien species are recorded in their new habitat yearly, but not all become invasive.
“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,” said Roy, adding that due to worsening environmental changes, the invasive alien species and their negative impacts “are likely to be significantly greater.”
“Even without the introduction of new alien species, already established alien species will continue to expand their ranges and spread to new countries and regions. Climate change will make the situation even worse.”
The IPBES expert assessment said a wide range of options were available to combat the spread and impact of invasive species. The Global Biodiversity Framework, agreed last year at the biodiversity COP15 in Montreal, has committed to a 50% reduction in the introduction and establishment of invasive species by 2030.
