Alien invasions: The effects of the global economy on nonmarine gastropod introductions into the United States

With the expanding global economy, increasing trade volume and internationa l trade agreements facilitating commodity movements worldwide, the risks of "alien" introductions are increasing. Of over 4,900 molluscan interception s from almost 100 countries by USDAAPHIS PPQ inspectors over the last five years on commodities entering the United States, some 369 gastropod taxa, b elonging to 197 genera in 71 families, have been identified. Although expec ted on agricultural and horticultural products, "hitch-hikers" also are fou nd in and on shipping containers, household tiles, military hardware, aquar ium supplies, and other items, as well as being deliberately introduced. Ma ny of these mollusks belong to a lengthening list of traveller species, and the number of introduced species in each country is increasing inexorably despite efforts to slow their invasions. A listing of these travelling spec ies is given, together with their distributions in the principal regions of the world with which the United States has commerce. This is drawn from a survey of the world malacological bibliography, which is provided. Most cou ntries lack or have minimal quarantine restrictions, or where inspection ag encies exist, they may be ineffective and/or underfunded. Local agriculture potentially will be negatively effected, native species adversely impacted , and the establishment of a non-indigenous species will create a reservoir for its further spread when that country exports its own products abroad. These invasive species may also be human and livestock disease vectors. As we lack specific ecological information for most of these taxa, there is an urgent need for the collection and pooling of any such data from concerned scientists and governments worldwide.