International travelers can introduce invasive species

International tourism has been hailed as economically important. Some experts even see ecotourism as an important part of environmental preservation. Unfortunately, there are environmental downsides to international travel as well, beyond the carbon footprint. 

A recent study from New Zealand looked at the potential for international travelers to introduce non-native and sometimes invasive species from abroad. This follows up on a 2011 study which showed that for every gram of soil carried on shoe soles, 2.5 plant seeds, 41 roundworms, 0.004 insects and a host of microorganisms were also carried along. These organisms were alive and potential threats to the local ecology. 

The experts found that international travelers can introduce new species both abroad and to their home country, effectively doubling their impact. 

The new research picks up where this study left off, investigating the role of international travel in the spread of exotic species. 

The researchers looked at the period from 2011 to 2017 and examined insects, spiders, mites, snails, plants and roundworms. They compared the interceptions of non-natives species to accommodation data for both international and domestic tourists. 

The team found that there was a significant correlation between the number of nights spent in hotels and the number of species intercepted. Interestingly, there was no noticeable difference between international and domestic travelers. This shows that even domestic tourism can spread invasive species around. 

“The core take-home message is that anthropogenic movements associated with tourism correlate with detection of exotic organisms in New Zealand,” explained the study authors. “The results also reinforce the need for biosecurity authorities to continue to allocate resources to managing the tourism pathway.”

The scientists suggest that some resources should continue to be used to intercept invasive species carried in by returning tourists. They also point out that there are other vectors such as sea freight to worry about, and suggest that the different vectors should be compared to allocate resources properly.

According to the researchers, understanding the links between international travelers and the potential biosecurity risks that these visitors may present is a new and important area of research.

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By Zach Fitzner, Earth.com Staff Writer