Invasive reptiles and amphibians have cost the global economy billions, study finds

Invasive reptiles and amphibians cost the global economy more than US$17 billion between 1986 and 2020, according to a recent study.

The analysis, published this week in the journal Scientific Reportsclaims that the transport of « alien species » into new areas is increasing at an unprecedented rate due to the globalization of human activity, and that this can lead to species invasions and extinctions of native species, damage to ecosystems and major economic impacts.

It’s « almost impossible » to list all the ways invasive species can affect an economy, said Ismael Soto, the study’s lead author and a doctoral student at the University of Bohemia in Plzeň, Czech Republic.

For example, he said, these economic costs can reach the real estate market if an invasive species becomes an « impossible to live near » pest.

Soto cited the Burmese python, which is invading the Florida Everglades and creating a dangerous environment for surrounding residents. He also pointed out that an invasion of brown tree snakes in Guam coincided with declining real estate prices over time.

The zebra mussel is one of the most troublesome invasive species in Canada. (Radio Canada)

“The economic costs are enormous for all invasive species,” Soto said. « We need to try to be aware of these costs and take control of the management of these species. »

The study breaks down the estimated US$17 billion cost into: $6.3 billion spent to control invasive amphibian species; $10.4 billion on invasive reptiles; and $300 million on cases involving the two.

To conduct the analysis, Soto and other colleagues used a database, InvaCost, which attempts to collate data on economically invasive species. Most of the numbers are taken from peer-reviewed literature or studies deemed highly reliable, but they note that they largely come from estimates and extrapolations, rather than empirical observations.

Research gaps

According to Soto, the economic costs of invasive species are underdocumented around the world. While carrying out the study, the researchers struggled to find documents in North America and Africa in particular, he said.

“We found that there are costs on every continent,” Soto said. « But maybe there just isn’t enough research on the economic costs in these areas. »

Monitoring the economic impact of invasive species is a relatively new area of ​​research and has the potential to capture the attention of Canadians, says Colin Cassin, policy manager at the nonprofit Invasive Species Center (ISC). based in Sault Ste. Marie, Ont.

« Some people may not care about the ecological impacts of invasive species, but what speaks to them is the fact that their home value just went down, » Cassin said.

The arrival of brown tree snakes in Guam coincided with a drop in real estate prices. (United States Geological Survey)

Such research is « an opportunity for us to connect with different audiences and make sure everyone understands the far-reaching implications. »

Canada does not have an environment where many invasive reptiles and amphibians can thrive, Cassin said. There are a few examples — such as the red-eared slider, an invasive turtle species — but they are not among the costliest invaders in Canada.

According international union for conservation of natureinvasive species are among the greatest threats to biodiversity.

Although not all introduced species are able to thrive in a new environment, some find the right conditions. They are generally able to reproduce and spread rapidly, often competing with native plants and animals for food, water, and space.

Japanese knotweed, zebra mussel and emerald ash borer have all taken their toll in parts of Canada.

Last year, the ISC conducted a cost-benefit analysis Phragmites, an invasive grass in Canada that grows well in moist areas such as drainage ditches.

The study looked at the costs of roadside maintenance and grass-related flooding, but also looked in more depth at potential impacts on a driver’s sightlines and whether there were any an increase in costs due to traffic accidents.

“There are a lot of things about the cost of invasive species that are either currently understood or have yet to be understood,” Cassin said.

A remote mower is used to remove overgrown grass in Lanark County, near Ottawa. (Submitted by Michelle Vala)


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