At its core, the model consists of two parts. First, the researchers sought to identify a small number of plant traits that could be used to predict invasiveness.
"Amazingly, we found that just four traits could discriminate pest from non-pest species with an impressive degree of accuracy," Schmidt said. "Namely, pest species tend to have some combination of the following traits: seeds that are in the mid-range of seed sizes, that have higher chromosome counts than their close relatives, that have affinities for both wetland and upland habitats and that have large native ranges."
"Second," said co-author John Drake, an associate professor at the Odum School, "we asked where to draw the proverbial line-in-the-sandin this case the line between probable pests and probable non-pestswhich requires accounting for the value of the ornamental plant trade and the costs associated with weeds. The economically optimal decision rule is the one that settles that line where it exactly balances the costs from invasion with the benefits from trade."
Schmidt explained that the cost of mistakenly keeping out a non-invasive plant was far lower than the cost of mistakenly allowing an invasive plant in.
To make these results equally accessible to scientists, decision-makers and the interested public, the researchers then encapsulated the resulting decision rule in a series of four graphics. Every plant species can be placed somewhere on these diagrams. The location on the diagram indicates the economically optimal policyeither to admit or deny import.
Although these methods were developed to aid decision-making about potential plant pests, the techniques used may be helpful for other problems in environmental ma
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University of Georgia