Smart Prevention of Aquatic Invasive Species
Eradicating an invader is very difficult. When it comes to aquatic invaders, an old adage rings true:
"An ounce of prevention is worth a pound of cure."
Tools that effectively forecast invasions are needed to channel prevention efforts to the inland waters that have the most to gain. A 'Smart Prevention Approach' to aquatic invaders is more likely to protect Wisconsin's lakes and streams from exotic colonists.
Interestingly, most exotic colonists do not successfully establish a population, and most established populations do not become invasive (Williamson 1996). Two critical challenges facing researchers are predicting which systems will be invaded, and which systems will be adversely impacted. To address such questions for lakes and streams of Wisconsin, we need to consider the invasion process as comprised of three sequential steps or 'filters.'
The first filter determines whether colonists can reach an uninvaded ecosystem. This depends on the dispersal mode of the invader, the frequency of human visitation, and potential for dispersal through stream networks. The second filter determines whether the invader is capable of surviving, reproducing, and establishing a self-sustaining population in the new ecosystem. In cases where colonists reach an ecosystem, they often fail to establish a population. This may be due to inappropriate environmental or biotic conditions, or the suite of problems encountered by populations at low numbers (Pimm 1991) The third filter determines whether an established invader adversely impacts the native ecosystem or biota. In some systems, invaders have little or no impact. In others, invaders wreak ecological and economic havoc.
References:
Pimm, S.L. 1991. The balance of nature? Chicago, University of Chicago Press.
Williamson, M. 1996. Biological invasions. New York, New York, USA, Chapman and Hall.