basis. Datasets need to be organized in a way that allows them to be analyzed and evaluated from the perspective of understanding invasiveness.

Much information has been gathered on the modes, pathways, and circumstances of organisms’ dispersal on all geographic scales (Ridley 1930, van der Pijl 1969); indeed, these topics have been active arenas of scholarship among biologists for over a century. However, full value of this information is seldom obtained. Instead, we find basic references providing much the same litany of pathways, in the same detail, as was assembled decades earlier (Baker 1972, 1978, 1989).

The huge literature on the natural history of species is simultaneously a strength and a handicap in contributing to our understanding of the invasion process; much of the relevant information is mixed with ancillary information. A more systematized manner is needed to report and to access what is known about the natural history of potential immigrants, including species with a record of invasion, and results of localized pest surveys or evaluations of biocontrol releases. Such a system could provide a relatively rapid process for determining what is known about a species’ natural history, native and current new ranges, habitat, hosts, prey, and impact. It could also minimize duplication of efforts, and identify priorities for research or survey activities.


In the following recommendations, the committee points to ways of strengthening the scientific basis for predicting the invasive potential of plant pests. The first three recommendations are directed toward USDA-APHIS and its regulatory activities because they are related to our understanding of the scientific basis of prediction. The other recommendations require action by USDA, other federal and state agencies, and the scientific community. Recommendations 4-7 are related to the documentation and standardization that are needed to understand invasions better. Recommendations 8-10 focus on needed research, and recommendations 11 and 12 point to the organizational infrastructure and scientific expertise that are needed to make headway in predicting invasions.


Recommendation 1. The Port Information Network (PIN) database maintained by APHIS is a potentially valuable source of information for understanding the pathways by which potential invaders arrive at U.S. borders, but the utility and availability of the data could be substantially improved. Sampling methodology should be statistically designed and implemented consistently. Sampling protocols at ports and borders should be re-evaluated and revised as necessary to ensure that pest interception data are accurate

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