ing of pests of U.S. crops and native U.S. species growing in foreign ranges. Such monitoring would provide early warning of nonindigenous species that, if introduced, would become threats in the United States. Australia has already begun a similar form of assessment for its invaluable native eucalypts growing in Southeast Asia, and its experience could form a valuable precedent (Wylie and Floyd 1999).
Recommendation 11. A central repository of information relevant to immigrant species would accelerate efforts to strengthen the scientific basis of predicting invasion. Information collected by federal, state, and international agencies, academic researchers, and others should be brought together in a single information facility or service so that it can be evaluated collectively, to permit the construction of needed datasets and the design of appropriate experiments, and to document the circumstances surrounding invasions.
The considerable information that is required to build comprehensive predictions of invasion would be best assembled by a central authority with strong ties to and guidance from user groups. The information needed is so diverse that only a facility with a specific mission to gather it and make it available will be effective in achieving an understanding of invasion and an ability to predict it. Requests for a centralized authority on biological invasion have been made by many in the scientific community (Ewel et al. 1999, Schmitz and Simberloff 2001). Information that could be collected by such a facility includes much of the types suggested in this report, such as the documentation of newly detected nonindigenous organisms in the United States, information on biotic invasions around the world, and the results of organisms released for biological control. The creation of a central facility of this type would help with efforts to predict invasive species and is consistent with the goals of the National Invasive Species Council (2001).
Recommendation 12. Focused scientific investigation is inadequate on nonindigenous species and prospective new environments from the overarching perspective of invasive potential. Multidisciplinary collaboration should be encouraged and supported among scientists with taxonomic expertise and those who specialize in population biology, community ecology, epidemiology, and simulation modeling. Multidisciplinary training of established and new investigators is needed to provide the expertise needed to make the study of invasion biology predictive.
In spite of a long history of interest in biological invasion, scientific inquiry in invasion is still nascent. Progress in understanding and predicting invasion will depend on how well the insights of investigators with diverse training can be coalesced and directed to decipher the myriad combinations of immigrant species,