In the latest issue of the online journal Conservation Ecology, you can read an article by Perrings et al. entitled "Biological Invasion Risks and the Public Good: an Economic Perspective." It's a very interesting discussion piece on the major role economics plays in the spread and management of non-native invasives. While the article does focus mainly on diseases, it makes policy recommendations that can be applied to all organisms (my favorite: insurance for importers of non-native species). Also in the same issue is an article by Graeme Cumming about modeling invasions, "Habitat Shape, Species Invasions, and Reserve Design: Insights from Simple Models"