The venomous Red Lionfish, which is native to the Indo-Pacific region, is an example of an invasive species that was introduced by humans to the Caribbean, where its population has exploded over the past 20 years. File photo by Bill Greenblatt/UPI | License Photo
Sept. 5 (UPI) -- Invasive species, including wildlife and plants, caused $423 billion in losses worldwide in 2019 and have since emerged as a major threat to the environment, native populations, and the global economy, according to a new U.N. affiliate report.
The Assessment Report on Invasive Alien Species and their Control, published Monday by the Intergovernmental Platform on Biodiversity and Ecosystem Services, blames humans for introducing more than 37,000 alien species to unconventional habitats around the world, while more than 3,500 were considered harmful to nature.
Representatives from 143 nations signed off on the study in Bonn, Germany, in an effort to raise awareness about the environmental issue as many governments were taking a lackadaisical approach to deal with the problem amid the worsening climate crisis.
Dozens of environmental experts from 49 countries conducted the study over more than four-and-a-half years in what's believed to be the most comprehensive assessment to date on invasive species.
The study urged nations to adopt new policies to mitigate the influx of biological invasions around the world.
The report shows 34% of invasion impacts occurred in the Americas; 31% from Europe and Central Asia; 25% from Asia and the Pacific; and about 7% from Africa.
About 75% of overall negative impacts were documented on land -- especially in forests, woodlands and cultivated areas -- while only 14% of impacts were recorded in freshwater, and 10% in marine habitats.
The impact was most palpable on 25% of the world's islands, where alien plants now outnumber native plant species, which threatened global extinction events.
Costs related to the impact on various ecosystems have quadrupled every decade since 1970, with alien species becoming one of the most direct causes of biodiversity loss, the report says.
"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 British professor Helen Roy, who served as co-chair of the study alongside professor Anibal Pauchard, of Chile, and professor Peter Stoett, of Canada.
The report noted that not all alien species become invasive; instead, invasive species constitute a specific subset of alien species that have successfully established themselves and proliferated.
Among the species known to be invasive, 6% were alien plants; 22% alien invertebrates; 14% alien vertebrates; and 11% alien microbes, the report says.
Indigenous communities worldwide were the most at risk due to their direct dependence on nature and as more than 2,300 invasive species have been found in native regions.
Many alien species were purposely introduced for perceived health and lifestyle benefits, however, the negative impact has become enormous for nature and humans after many decades.
The study points out current examples of impacts on native species, including the shifting habitats of North American beavers and Pacific Oysters.
"Invasive alien species have been a major factor in 60% and the only driver in 16% 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," Pauchard said as part of the study. "In fact, 85% of the impacts of biological invasions on native species are negative."
Nearly 80% of the documented impacts of invasive species were negative for humans, especially when it came to the food supply.
The scope of the damage was global, with impacts affecting European shore crab, commercial shellfish beds in New England, and fisheries in India that have been invaded by the Caribbean false mussel.
Similarly, 85% of impacts were contributing to the spread of diseases like malaria, Zika and West Nile Fever as invasive mosquito species have swarmed into far-off regions.
Invasive species have also hurt fisheries on Lake Victoria where tilapia has dried up due to the spread of water hyacinth -- the world's most widespread terrestrial invasive alien species, the study says.
Lantana, a flowering shrub, and the black rat are the second- and third-most widespread invasive species in the world today.
"It would be an extremely costly mistake to regard biological invasions only as someone else's problem," Pauchard continued. "Although the specific species that inflict damages vary from place to place, these are risks and challenges with global roots but very local impacts, facing people in every country, from all backgrounds and in every community - even Antarctica is being affected."