|A research plot of Miscanthus.|
A University of Arkansas researcher and his colleagues are calling for caution in developing dedicated energy crops, citing the possibility of some of those biofuel crops becoming invasive species.
Robert N. Wiedenmann, professor of entomology, and his colleagues S. Raghu, Roger C. Anderson, Curt C. Daehler, Adam S. Davis, Dan Simberloff and Richard N. Mack put forth their argument for ecological studies of biofuel crops in the policy forum in the 22 September issue of Science.
Most of the traits that are touted as great for biofuel crops—no known pests or diseases, rapid growth, high water-use efficiency—are red flags for invasion biologists. We want to start a dialog and approach the question of biofuels systematically.—Robert N. Wiedenmann
The authors of the article in Science call for an examination of potential invasiveness as crops are examined for their biofuel potential and before putting such crops into large-scale production.
Seemingly benign crops that have become invasive species have already occurred in the United States. Wiedenmann and his colleagues cite the case of Sorghum halepense, otherwise known as Johnson grass. Johnson grass was introduced as a forage grass and now has become an invasive weed in many states, causing up to $30 million annually in losses for cotton and soybean crops in just three states.
One proposed biofuel crop, Miscanthus, can grow up to eight feet in six weeks. Wiedenmann describes it as “Johnson grass on steroids.”
Plants like these, particularly grasses, have great potential from an energy standpoint, but the benefits need to be balanced with the costs.—Prof. Wiedenmann
Although invasive species are traditionally thought of as introduced species, a native species also can become invasive through alterations to the environment, Wiedenmann said. One example: the removal of oak and chestnut trees along much of the east coast has led to sugar maples becoming invasive in some areas.
Invasive species alter ecosystems in ways that can cause both ecological and economic harm. Since 1999, the U.S. government has had an invasive species council, which develops invasive species management plans.
Researchers investigating the potential for biofuels tend to be engineering or agricultural specialists who are looking at maximizing energetic conversion or crop size. Wiedenmann and his colleagues want to see ecologists at the table with engineering and agricultural researchers addressing the potential for invasiveness.
“Adding Biofuels to the Invasive Species Fire?”; S. Raghu, R. C. Anderson, C. C. Daehler, A. S. Davis, R. N. Wiedenmann, D. Simberloff, R. N. Mack; Science 22 September 2006: Vol. 313. no. 5794, p. 1742 DOI: 10.1126/science.1129313