Threats posed by invasive species are "enormous"

An international team of scientists is warning about the growing threats of invasive species. According to the researchers, urgent action is required to prevent, detect, and control alien species at both local and global levels.

Invasive animals, plants, and microbes often thrive when they are introduced to new habitats where they do not occur naturally. Their presence can be extremely detrimental to the environment, economy, and human health.

Professor Petr Pyšek of the Czech Academy of Sciences is the study’s co-lead author. 

“As our knowledge about invasive alien species increases, the problems associated with biological invasions are becoming clearer,” said Professor Pyšek. “The threats posed by invasive alien species to our environment, our economies and our health are very serious, and getting worse. Policy makers and the public need to prioritize actions to stem invasions and their impacts.”

The researchers found that the prevalence of invasive species is rapidly increasing, with more than 18,000 alien populations currently listed worldwide. 

Laura Meyerson is an associate professor of Natural Resources Science at the University of Rhode Island. She explained that the escalation of biological invasions can be attributed to a rise in the number and variety of pathways through which species spread, including the online trade of unusual pets and the transport of species across oceans on rafts of plastic.

The researchers said that the scale of the problem is enormous. A 2017 study reported that invasive species contribute to 25 percent of plant extinctions and 33 percent of animal extinctions. At the same time, environmental costs associated with alien species in the United States, UK, Australia, South Africa, India, and Brazil are more than $100 billion collectively.

Climate change, land-use changes, and international trade are compounding the effects of biological invasions. For example, global warming is helping alien species thrive in new regions.

The research is part of an initiative called World Scientists’ Warning to Humanity: A Second Notice, which calls for urgent change to protect life on Earth. Published in 1992, the first notice was supported by 1,700 scientists who warned that humanity was on a collision course with the rest of the natural world. Now, 25 years later, the follow-up evaluation is supported by 15,000 scientists who report that we have failed to make sufficient progress. 

The study authors emphasize that biological invasions can be managed and mitigated, and point out techniques that are working around the world. In New Zealand, the introduction of stricter border controls has led to a progressive decline in the rate of fungal plant pathogens entering the country. 

Study co-lead author Professor David Richardson pointed out that countries such as Australia and New Zealand have made biosecurity a national priority. 

“South Africa has invested heavily in a massive national program focused on reducing the negative impacts of widespread invaders on ecosystem services, especially the delivery of water from catchments invaded by alien trees. But action is needed more widely at both national and international levels in order to tackle the challenges effectively.”

The study is published in the journal Biological Reviews.