The possibility exists that crops that are to serve as lignocellulosic feedstocks for transport biofuel production may turn out to be invasive species. The selection for ‘weedy characters ’ in such species, which allow for cultivation on marginal lands with relatively low inputs of nutrients, is conducive to such risk (Barney and DiTomaso 2008). The impacts on ecosystem services of invasions by species involved in biofuel production are strongly dependent on the nature of the invader and the extent of the invasion. However, effects may be considerable. One of the species considered for lignocellulosic biomass production is reed canary grass (Phalaris arundinacea L.). This grass species is able to invade wetlands and impact their hydrology. For the most part, the outcomes of such invasions are considered detrimental (Zedler and Kercher 2004). Stream banks may also be invaded by reed canary grass (Lavergne and Molofsky 2004). There is, furthermore, some evidence that sweet sorghum and giant reed (Arundo donax) are invasive in specific ecosystems in the USA (Barney and DiTomaso 2008; Royal Society 2008). Jatropha curcas, a source of biodiesel, is considered as invasive in South Africa and as weedy in Australia (Achten et al. 2009).

Also, the production of seaweeds for biofuel production may give rise to invasive species. A case in point is the macroalga Kappaphycus alvarezii. This native to the Philippines has given rise to invasions of coral reefs in Hawaiian and Indian waters as an unintended effect of cultivation (Bagla 2008).