Recommendation 7. A consensus on procedures to measure the impact of invasive species should be forged in the scientific and regulatory communities, and there should be more reporting of impacts of invasive species with standardized measures.


Recommendation 8. Research on host specificity among pathogens and the correlation of some life-history traits (such as dispersal mode, reproductive system, and host range) with their documented ability to invade should be undertaken in relation to potential environments in new regions or areas. Question-oriented experimentation to elucidate relationships among species’ traits and their new environments and hosts should be supported.

Recommendation 9. The release of nonindigenous organisms for biological control presents an opportunity to collect detailed demographic data on immigrant populations from the moment of their introduction. A substantial effort should be made to document the fate of these organisms, including the efficacy of the introduced organism on the target pest and on nontarget species, as a guide to the performance of unintended releases and as a mechanism to improve risk assessment in deliberate introductions of nonindigenous species.

Recommendation 10. Plants native to the United States that are growing in other countries, such as in botanical gardens and aboretums, should be monitored to determine the species to which they are susceptible and to evaluate the potential for these species to arrive in the United States. The severity of the damage to native U.S. plants by pathogens, arthropods, and other taxa, and the abiotic and biotic forces that contribute actively to the damage should be documented.


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.

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

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