I have found an interesting piece of information on ways to prevent invasive species from occurring.

First is, by volunteering to remove invasive species from natural areas which our team is eager to do at Hawk Mountain. Second, monitoring and reporting about new invasive species. Third way is by encouraging travelers, hikers, boaters etc. to not carry fruits, vegetables, plants and animals to other places as it can carry pests which might lead to introduction of invasive species. Fourth, homeowners should use certified weed free forage, fire wood, gravel, mulch and soil.

These are some of the ways to prevent the introduction of invasive species.

Source:

http://www.invasivespeciesinfo.gov/news/whatyou.shtml