February 16th, 2012 by

By Katrina Marland

The Princess Tree, introduced to the US as an ornamental, muscles out other plant species. (Credit: James Allison,Georgia Department of Natural Resources)

Species, that is. Invasive species are a big problem. They wreak havoc in our native ecosystems, result in massive losses of biodiversity and cost the U.S. billions of dollars every year. Some species are fairly obvious, such as the recently-publicized pythons in the Everglades, while others can be so subtle that you may not even notice them — only the effects they have on the ecosystem. Because some of these species can hide out so well, scientists have long been working on new ways to detect them and track them back to their source to stop the outbreak.

With today’s variety of invasive plants, insects and animals — from kudzu and zebra mussels to the emerald ash borer and the princess tree — the sheer number of invading species seems overwhelming, and it becomes harder and harder to track an outbreak back to its source where scientists can begin to fight back. But researchers at the UK’s Queen Mary’s School of Biological and Chemical Sciences have found that we can track invasive species the same way we track certain types of criminals: with geographic profiling (GP).

You may not have heard its official name before, but you probably already know what GP is, particularly if you’ve seen a few episodes of “CSI” or “Law and Order.” This type of profiling uses the locations of crimes committed, combined with knowledge of the crimes themselves, to predict where the criminal may live or operate from. The team from Queen Mary’s, whose research is published in the journal Ecology, shows that the same method can be used to find the source population of an invasive species. Not only that, but GP actually works better than other mathematical models that researchers currently use.

The Emerald Ash Borer, introduced from Asia, has killed millions of trees in the US. (Credit: Debbie Miller, USDA Forest Service)

The established methods of tracing invasive species tend to take longer to find the sources, especially in cases where there are multiple source populations, giving the species more time to establish a foothold in the ecosystem. The more source populations there are, the longer it takes the traditional methods to track them all down. Geographic profiling, on the other hand, works much faster when applied to cases of multiple source populations. In the study’s computer simulations and in working with real-life data sets on invasive species from Britain’s Biological Records Centre, the GP method traced the invaders back to their sources faster and more accurately than the other methods.

I’d never have thought that criminology and biology could have much to do with each other, but in this case, crossing two unrelated fields led to an incredibly valuable tool in  worldwide efforts to protect native ecosystems. Watch out, invasive species: We’re on to you.

Want to learn more about invasive species and how they affect native ecosystems? Or what you can do about it? Check out these articles from past issues of American Forests magazine:

“Alien Invasion!” By Carrie Madren

“Backyard Biodiversity” by Douglas Tallamy