Mitigating the potential for invasive spread of the exotic biofuel crop, Miscanthus × giganteus

Although herbaceous perennial crops are becoming a larger component of bioenergy production both in the United States and worldwide, there is growing concern that these crops pose a substantial risk of biological invasion. Miscanthus × giganteus, a sterile hybrid native to Asia, is considered an ideal biofuel crop for lands that are poorly suited for annual food crops and is currently being tested by growers. A fertile variety of M. × giganteus was developed by seed and energy companies in an effort to decrease the costs associated with planting rhizomes. No regulations have been established to manage the risk of invasion by the fertile variety. Because bioenergy production is expanding rapidly, and the few studies to quantify invasion risks in this species have addressed small spatial scales, we used a modeling approach to explore a broader domain of invasion scenarios at landscape scales. We implemented a spatially-explicit population model of fertile M. × giganteus to determine the efficacy of proposed management strategies in limiting or slowing the spread of this species. We found that fertile M. × giganteus may spread rapidly outside of field margins, and the ability of localized management strategies to curtail spread was highly sensitive to M. × giganteus first year survival and the amount of suitable habitat within the larger landscape. Commercialization of novel “bioeconomy crops”, such as fertile M. × giganteus, could increase both production and resource conservation in agriculture; however, these crops may also produce ecosystem “disservices” such as biological invasion and accompanying risks to native species. Landscape-scale modeling that allows for rapid testing of the interactions between new crop genotypes and landscape configurations will be a powerful tool for exploring the ecological risks posed by new bioeconomy crops.