Modeling biological invasions of inland waters

The discipline of invasion biology suffers from a number of problems, not least of which is a lack of a central, organizing paradigm. Ecologists have for decades sought to relate invasion success both to characteristics of invaded communities and to those of the invading species (see references in Davis 2005), the results of which have only served to demonstrate the highly system- or species-specific nature of many invasions. One recent development that holds promise for resolving this problem has been a recognition that successful invasions result from a series of inter-connected stages: introduction effort across biogeographic barriers, suitability of physiochemical conditions in the new environment, and survival in the local biota; each of these stages may pose differing demands on entrained species and may be studied independently (Carlton 1985, Williamson and Fitter 1996, Richardson et al. 2000, Kolar and Lodge 2001, 2002, Colautti et al. 2006). While many patterns in nature may have alternate explanations, none of which takes logical precedence for testing over any other, the same cannot be said for hypotheses that may account for success of non-indigenous species (NIS).