International biodiversity organization chronicles global threat from invasive alien species

Global assessment team includes URI Professor Laura Meyerson

KINGSTON, R.I. – Sept. 7, 2023 – In a landmark assessment, a worldwide scientific intergovernmental group on biodiversity – which includes a professor from the University of Rhode Island – has highlighted evidence of the global spread and destruction caused by invasive alien species and provided policy options to deal with the challenges of biological invasions.

The report, produced by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services for the United Nations, found that the threat posed by invasive alien species introduced into new ecosystems is enormous. Annually, invasive alien species caused an estimated $423 billion in damages to nature, food sources and human health in 2019. And harmful alien species have contributed to 60% of recorded animal and plant extinctions, and were the sole factor in 16% of extinctions.

“The rapidly growing threat that invasive alien species pose to biodiversity, ecosystem services, sustainable development and human well-being is generally poorly understood,” said Helen Roy, co-chair of the assessment group and professor at the UK Centre for Ecology & Hydrology. “This authoritative report will make a major contribution to filling critical knowledge gaps, supporting decision-makers and raising public awareness to underpin action to mitigate the impacts of invasive alien species.”

“This is the first global report on invasive alien species anywhere,” said Laura Meyerson, a URI professor in natural resources science and a contributing lead author on the report. “It’s truly an effort of scientists from around the world. The data touch on every world region, every biome and all major taxa—plants, vertebrates, invertebrates, micro-organisms, fungi. It is a truly impressive and comprehensive report by a very dedicated group of scientists.”

The report, which was presented Monday, Sept. 4, in Bonn, Germany, took more than four years to develop and included the work of 86 international experts from 49 nations, and another 199 contributing authors from across the world.

In a 2019 assessment, the organization found that invasive alien species – plants, animals and microbes introduced into new environments – are one of the five major drivers of biodiversity loss. The 2023 report, “Assessment Report on Invasive Alien Species and Their Control,’’ compiled evidence of the threat based on 2019 data, providing an assessment of the future growth of invasive alien species and thoughts on controlling coming biological invasions.

The report found more than 37,000 alien species that have been introduced by people to areas around the world – including more than 3,500 harmful invasive alien species that are negatively impacting nature and people’s quality of life.

The global threat reaches across regions and ecosystems, the report says. The Americas contributed 34% of the reported negative impacts of biological invasions, while Europe contributed 31%, Asia and the Pacific 25%, and Africa about 7%. About 75% of negative impacts were reported on land, such as forests, woodlands and cultivated areas, and another 14% in freshwater and 10% in marine habitats.

While not all alien species cause negative outcomes, the report says 6% of alien plants, 22% of alien invertebrates, 14% of alien vertebrates and 11% of alien microbes are known to pose major risks to nature and people. Invasive alien species negatively impacted people through damaged food supplies, health effects such as the spread of disease by invasive alien mosquito species, and threatened livelihoods, such as damages caused by the European shore crab on commercial shellfish beds in New England.

Of the 37,000 alien species known today, 37% have been reported since 1970, fueled by the growth of global trade and human travel. If nothing changes, the report warns, the numbers of alien species will continue to grow – and their effects on ecosystems increased by the interaction with such forces as climate change.

The report, though, highlights that future biological invasions, invasive alien species and their impacts can be prevented through effective management and integrated approaches. Prevention measures that can be successful include border biosecurity and strictly enforcing import controls, eradication, and containment through physical, chemical or biological measures.

“One of the most important messages from the report is that ambitious progress in tackling invasive alien species is achievable,” Peter Stoett, co-chair of the assessment and professor at the University of Ontario Institute of Technology, said in a press release. “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.”

URI’s Meyerson was among the contributing lead authors who joined the report’s co-chairs in drafting the lead chapter and a Summary for Policy Makers. She was the lead author of the report’s second chapter offering a global analysis on the status, trends and data gaps on invasive alien species across regions and taxonomic groups. The chapter, which integrated seven global databases, is the largest single database of alien species available, including 37,591 alien species and 5,260 invasive alien species, she said.

While the global assessment focused on large regions, examining the evidence on a global scale, the report is highly relevant to Rhode Island and New England, she said. “The assessment includes information on many species that are plaguing our region including phragmites, green crabs, chestnut blight, Japanese knotwood, and beech leaf disease,” Meyerson said. 

“The biggest outcome from our negotiations at the IPBES in Bonn is that the report presented overwhelming evidence that for the very first time galvanized a global consensus on the threats posed to nature, nature’s services to people, and the economy,” she added. “The report’s Summary for Policy Makers was approved by 143 member countries and is a global call to action.”

To read the group’s media release or download the assessment’s summary, click here.