Biofuel crops being promoted and planted as a “;green”; renewable solution to energy needs might actually be aggressive invasive pests, caution University of Hawaii-Manoa researchers.

They did weed risk assessments to compare invasion risks of 40 biofuel crops proposed for Hawaii versus a random sample of 40 introduced non-biofuel plant species.

The researchers found 70 percent of proposed biofuel crops have a high risk of becoming invasive and are two to four times more likely to establish wild populations when compared with other introduced plants.

The assessments, funded by the Hawaii Invasive Species Council, included a plant's biology, geographic origin, pest status elsewhere and information published on its behavior in Hawaii.

The findings, “;Assessing Biofuel Crop Invasiveness: A Case Study,”; are reported in the journal PLoS ONE, a Public Library of Science resource.

“;You can have a plant that's beneficial and invasive,”; said Christopher Buddenhagen, who conducted the study with Charles Chimera and Patti Clifford in the UH-Manoa Pacific Cooperative Studies Unit.

“;It might make money but invade a natural area and have an impact.”;

For example, he pointed to jatropha curcas, “;supposedly a miracle plant ... It's supposed to be really productive for biodiesel and easy to grow.”; But the seeds are toxic and it's considered invasive in other parts of the world, he said.

Buddenhagen, who recently left UH to join SWCA Environmental Consultants, said a lot of interest in biofuel crops and speculative investment in alternative energy companies was sparked when gas prices were higher.

Except for noxious weeds, he said Hawaii has a very short list of plants subject to regulations and he doesn't know if any biofuel crops are on the list. “;Apart from that, the right to plant anything on the land is sacrosanct if you're a private owner,”; he said, pointing out this could be a problem if a big land owner decided to plant a crop likely to be invasive.

Buddenhagen said some high-risk crops might be grown if measures were taken to keep them from spreading: “;There is a lot of literature suggesting we need to be careful.

“;Basically, we have to live with a lot of invasive species we have,”; Buddenhagen added, “;but if they are widespread over thousands of acres—a scenario you would need for significant business—you're altering the landscape just by planting in the first place. And if the plants spread, they are potentially altering the neighboring lands also.

“;By identifying the species with the highest risk and pushing for planting guidelines and precautionary measures prior to widespread planting, we hope to spare the Hawaiian Islands and similar tropical ecosystems from future economic and environmental costs of the worst invaders while encouraging and promoting the use of lower-risk alternative crops.”;