Biological invasions are believed to be a major driver of biodiversity change, and cause billions of dollars in economic damages annually. Our models show that the emerging global shipping network could yield a three-fold to 20-fold increase in global marine invasion risk between now and 2050,

...says senior author Brian Leung, an associate professor in McGill’s Department of Biology and School of Environment.

Shipping accounts for an estimated 60% to 90% of marine bio-invasions. In some cases, ships transport living organisms through ballast water, which is taken up to stabilize the vessel. In others, species hitch a ride to new environments by attaching to the hulls of ships.

To understand how biological invasions will change, we need to understand how shipping patterns could change. Our study suggests that, unless appropriate action is taken, we could anticipate an exponential increase in such invasions, with potentially huge economic and ecological consequences,

...says lead author Anthony Sardain, a graduate student in Leung’s lab at McGill.

Meanwhile, major policy initiatives such as the international BWM Convention, put in place in 2017, represent the latest global effort to control bio-invasions.

While it’s too early to gauge the efficacy of the Convention globally, this work suggests it is in the right direction, noted Dr. Leung.

As wealth and population increase, so too does demand for goods and services that are not available locally. The wide range for increases in bio-invasion risk estimated by the models – anywhere from three-fold to 20-fold – stemmed from uncertainty in the underlying socioeconomic trajectories.

Despite this large range, all scenarios point to an increase in both shipping and invasions. That should alert us to the gravity of the situation, and the importance of measures to curtail biological invasions,

...Sardain notes.

The Natural Sciences and Engineering Research Council of Canada funded the research. Findings were published in the journal Nature Sustainability.