Invasive Plant Science and Management — Cultivation of large grasses for bioenergy production is gaining interest as a renewable fuel source. A sterile hybrid, giant miscanthus, is a promising bioenergy crop that, unfortunately, carries a high establishment cost for growers. A new seed-bearing line may have economic benefits, but it also bears consequences as an invasive species if it escapes cultivation.
The article “The Relative Risk of Invasion: Evaluation of Miscanthus × giganteus Seed Establishment,” reports the results of field tests on the fertile “PowerCrane” line of giant miscanthus. There is a dearth of research on the ability of such newly developed fertile crops to escape cultivation. Such research can identify susceptible habitats and help advance management plans in preparation for widespread commercialization. (Full text of the article is in Invasive Plant Science and Management, Vol. 7, No. 1, January-March 2014, now available.)
Giant miscanthus produces abundant biomass, has few pests, and requires few inputs after establishment. While these traits make it an excellent bioenergy crop, they are also traits of invasive species. This species has the ability to produce up to 1 billion spikelets per acre per year that can disperse seed into the wind.
In this study, seedling establishment was evaluated in seven habitats: no-till agricultural field, agricultural field edge, forest understory, forest edge, water’s edge, pasture, and roadside. Experiments were conducted at three sites in the southeastern United States—the area most likely to see increased bioenergy production due to its ideal growing conditions.
Giant miscanthus seedlings emerged in roadside and forest edge habitats at all study sites, and early in the growing season, there were more giant miscanthus seedlings in the agricultural field than any of the other species. Despite its potential, in these tests giant miscanthus experienced high seedling mortality—99.9 percent overall. However, identification of even a small population of an escaped species at an early stage can be critical for effective eradication. A 99.9 percent mortality rate in spikelets per acre leaves 1 million spikelets in the seed bank! This study looks at the early establishment phase of invasion, which is only part of the process. With growing demand and federal mandates, bioenergy production is on the increase, and evaluation of these crops’ potential as invasive species will be essential for management.