There is growing concern that biofuel crops will escape cultivation areas and invade surrounding forests, wetlands or grasslands. Many of the desirable traits of biofuel crops, such as rapid growth, short generative time, disease resistance and a broad tolerance to a variety of environmental conditions, are also characteristic of successful invading plant species. Proposed biofuel crop plants, like giant reed (Arundo donax) and Chinese tallow (Triadica sebifer), are such invaders.

Predicting the risk associated with non-native plant species invading new areas currently relies on qualitative expert opinion, literature-based risk assessment tools or climate matching and demographic models. These tools can be suitable and relatively accurate for some groups of non-native species but may be of limited use when attempting to assess the invasion risk of new biofuel crop cultivars, whose plant life history is little known.

As we report in Environmental Research Letters (ERL), we believe that new experimental tests are needed to predict these risks accurately. Such tests should begin with studies of the basic biology and life history of the taxon under controlled local conditions. Once the biology and growth requirements of the proposed crop are better known, further experiments should be conducted in quarantined semi-natural areas where escape and spread can be carefully monitored. Ultimately, the experiments should be performed across the entire proposed geographic range for a particular biofuel crop.

By undertaking experimental tests for invasion risk, we will be able to obtain specific information that could greatly improve our chances of determining whether biofuel crops pose a threat to surrounding natural areas or not. Using experiments to further understand the invasion risk of biofuel crops will allow both progress in the sustainable development of bioenergy and the promotion of practices that protect natural areas from non-native species invasion.