Date: 3/30/99

Time: 11:15

Type: Symposium

Number: 99

Invasion biology and ecological risk assessment: The first step in exotic species management

*R.C. Venette, Department of Entomology, University of Minnesota, St. Paul, MN 55108
Contact e-mail: venet001@tc.umn.edu

Biological invasions begin with the introduction of a species into areas outside its native range. Principles governing the process of invasion pertain to all exotic species, pests and introduced biological control agents alike. All invasions, regardless of socioeconomic impact, proceed through the phases of arrival, establishment, integration, and spread. Through quantitative ecological risk assessment, we strive to determine the probability that a species will complete all phases of invasion and, in some cases, have adverse economic effects. The ability to accurately measure such probabilities depends on the quality of theory to identify pertinent biological data and the availability of corresponding information for a species of interest. General theory suggests that a species' past invasion success, native range size, or physiological growth requirements are valuable indicators of the probability of establishment. Individual characteristics (e.g. weight, lifespan, or clutch size) are less reliable predictors. Conditions at an invasion site, including the degree of disturbance, native species diversity, and climatic similarity to previously invaded regions, also govern the outcome of an invasion. Ecological risk assessment is the logical first step in developing a management strategy for an exotic pest. For example, we demonstrate the utility of climate matching and logistic regression to quantify the probability of pink bollworm, Pectinophora gossypiella (Saunders), becoming established in southeastern US cotton. Principles of invasion biology provide a solid foundation for policy decisions. Because the estimated probability of pink bollworm establishment is >50% in most cotton producing states, we believe continued monitoring for the pest is justified.

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