CBC News, February 26, 2009 (TORONTO)

Those who keep track of invasive species could be in for a busy month in June of next year, when airplanes are expected to shuttle many critters - and the diseases they carry - between distant destinations, says a U.S. researcher.

That's when temperature, humidity and rainfall at an airplane's departure point are most likely to match those at its destination, says Andrew Tatem, a professor at the University of Florida's Emerging Pathogens Institute. That means plants, animals and insects that take off from their natural habitats will find a hospitable environment when they land.

Tatem examined global climate models for 2007 to 2010, cross-referencing them with traffic volume forecasts on existing airline networks. He concludes climatically sensitive organisms are more likely to find their destinations hospitable in June 2010 at any other time during that period.

His prediction could help people who monitor airline flights - and the people, baggage and cargo aboard - to better plan for finding and intercepting invasive species.

Tatem's study was published online last month in the journal Ecography, and is based on work he did while at Oxford University.

He said his model shows that while climates at various departure and arrival cities are not expect to change greatly over the next couple years, more flights from countries with expanding economies will have a significant effect on moving species around.

"The rapidly growing economies of China, India, Russia, Mexico, eastern Europe, the Middle East and northern Africa are expected to provide the largest increases in air traffic," Tatem writes. "With growth of over 30 per cent by 2010, organisms will have many more opportunities to move between these regions and those connected by air routes to them."

Invasive plants, animals and insects can hitch rides on or with people either accidentally or knowingly.

"Some studies have shown that mosquitoes can fly on randomly, or they may get into baggage," he said in a news release. "But some things, like plant pathogens, happen when people purposely bring fruit aboard, or they may bring in a plant that makes it through inspections, or they may just have seeds stuck in the soles of their shoes."

Tatem argues, as do others, that such events can threaten local economies, public health and native ecosystems over the long term.

While not all invasive species damage local ecosystems, when they do, the results can be catastrophic for homegrown organisms. Next to habitat destruction, alien species are the leading cause of extinctions worldwide, according to a study published in 2006 the scientific journal Frontiers in Ecology and the Environment.