Eradication——preventing invasions at the outset

A growing number of invasive animal populations——both vertebrate and invertebrate——have been completely eradicated. These projects usually have been on islands, but some have been on large continental areas, and many technologies have been used. Total eradication of plant populations has been reported less frequently, but there are nevertheless many successes. Though biological features may tend to make plant eradication more difficult than animal eradication, the difference in the number of success stories is probably more due to greater enthusiasm, persistence, and perhaps resources devoted to animal eradication than to biological differences. There is every reason to believe that many plant populations could be eradicated, particularly if eradication campaigns were coupled with a monitoring system that detects invasions early. Features conducive to successful eradication are (1) resources must be adequate, and there must be a commitment to see the project through to completion; (2) clear lines of authority must be established; (3) the biology of the species must be appropriate; (4) the target species must be detectable at low densities; and (5) subsequent intensive management of the system, such as for restoration, may be necessary. For success in some eradication campaigns, rapid reinvasion must be unlikely; in other instances the economics of the situation may make the attempt worthwhile even if reinvasion ensues. A failed eradication effort need not be a mistake, particularly if the eradication method used would have been utilized in traditional maintenance management. Further, the inspirational value of an eradication campaign and its enlistment of citizen support may help sensitize the public to the entire problem of invasive introduced species. Expanded eradication efforts can potentially effect enormous ecological and economic savings.