In the 1930s, soil used as ballast to weigh down cargo ships from South America to Mobile, Alabama introduced the red imported fire ant to the southern United States. Since then, the ants have been found as far north as Maryland and as far west as California, shorting out streetlights and eating through crops and native plants in the process.
Plant pests like the fire ant cost the U.S. an estimated $37.1 billion per year in agricultural and forest ecosystem losses. And since these pests primarily enter the country through international hubs like Mobile and then spread to nearby ecosystems, the early detection of exotic pests should start at the most vulnerable urban areas.
At least that is the approach Manuel Colunga-Garcia from Michigan State University and colleagues propose in the March issue of Ecological Applications. The researchers suggest that, by establishing specific risk zones and using the information to focus resources, officials can take additional measures to prevent an influx of exotic pests while gaining knowledge about invasions.
"We can learn from cases like the fire ant that the first line of defense against exotic pests is inspections at U.S. ports," says Colunga-Garcia. "But, it doesn't stop there. With the sheer volume of imports that enter the U.S. on a daily basisonly about two percent of the imports are actually inspectednew measures have to be implemented. Our risk-zone analyses, based on recent pest invasions across an urban gradient, can help prioritize surveillance efforts."
The urban gradient framework the researchers describe starts at forests and farms in areas with the densest population and spreads outward to rural areas. The researchers base their framework on two basic assumptions: 1. The threat of introduction is greatest in urban areas receiving large quantities of imported products and their associated wood packaging, like pallets and crating that are known to harbor exotic pests
|Contact: Katie Kline|
Ecological Society of America