Report Predicts Bioenergy Crop Invasion

A new report released by the National Wildlife Federation (NWF) details yet another in a long and growing list of ecological and economic threats from industrial-scale biomass energy: the risk of bioenergy crops becoming invasive species.

Growing Risk: Addressing the Invasive Potential of Bioenergy Feedstocks discusses the negative impacts on the environment and the economy that are likely to result from the cultivation of certain plant and tree species to supply an expansion of biomass electricity and transportation fuels in the US.


Air pollution, carbon dioxide emissions and forest degradation have been front and center in the debate about whether or not to expand our nation’s utilization of industrial scale biomass energy—already making up nearly half of the nation’s “renewable” energy (electricity and heat) supply. A new blip on the radar is a partnership between the biomass industry and federal and state governments to plant millions upon millions of acres of bioenergy crops, including Miscanthus grass, Giant cane, and genetically engineered eucalyptus trees, which could result in the “loss or degradation of native ecosystems, declining soil and water quality, and the invasive potential of the feedstocks themselves,” according to the report.

Report co-authors Aviva Glaser, Legislative Representative for Agriculture Policy and Patty Glick, Senior Climate Change Specialist for National Wildlife Federation, zero in on how a bioenergy crop boom can have “significant impact on ecosystems as well as human societies by disrupting food webs, decreasing biodiversity, altering important ecosystem functions such as fire ecology, damaging agriculture and infrastructure, and harming human health.”

Land use is one of the issues relevant to a bio-crop explosion, according to the report, where fuel crops could end up competing with food—as has already happened with corn ethanol. Collateral damage to ecosystems would also come into play with “the potential for natural areas such as forests or grasslands to be converted to cultivated bioenergy cropping systems or monocultures.”

Alarmingly, the traits that make an ideal species of bioenergy crop are often the very same traits that qualify a plant as an invasive species, including “rapid growth rate, resistant to pests and diseases, high yields, ability to grow in a wide range of climates and habitats, and rapid regrowth or self-propagation,” as depicted in NWF’s chart below. Once an invasive species enters an ecosystem, it can often “out-compete native species for limited resources such as space to grow, light, nutrients and water.”


Growing Risk cites research showing that “nearly half of the species listed as threatened or endangered under the U.S. Endangered Species Act are at risk, at least in part, due to the impacts of invasive species.” The more bioenergy crops cultivated, the higher the chance of them escaping into ecosystems, which could prove “devastating for native ecosystems as well as the economy.”

Glaser and Glick critique efforts by the federal government to address invasives as “reactive, incremental, piecemeal, and focused primarily on protecting agricultural productivity,” pointing to the out-of-control spread of kudzu, common reed, and purple loosestrife across the nation. The authors contend that currently “few safeguards exist in law to prevent the spread of invasive species through bioenergy cultivation.”

Prevention is the best strategy, according to the large and influential national environmental organization, arguing that “evidence indicates that in most cases, species invasions are essentially irreversible.” The report blames part of the US Department of Agriculture’s (USDA) failure in stemming the invasive tide on a “conflict of interest when they not only promote and support agricultural commodity production, including for bioenergy, but also have the responsibility for enforcement of noxious and invasive species statutes.” NWF calculates the economic impact of the US invasive problem at $34.5 billion.

What about removing invasive species that have already found their way into ecosystems and burning them in biomass power incinerators or converting them to liquid fuels? Aside from the air pollution and greenhouse gas emissions that are a byproduct of all forms of combustion and incineration, honing in on existing invasive plants as a fuel source can have unintended consequences, according to the report.

The first problem with harvesting invasives already present in the environment is the free market reality that “potential economic gains from their use will encourage efforts to maintain their presence on harvested landscapes, or even lead to their cultivation and expansion into new areas.” If a targeted plant is eventually extirpated from the environment, economic pressures would likely favor intentional cultivation of the species, running the risk of a reintroduction into natural systems.

If a biomass incinerator—dependent on a high volume flow of plant material—is built and the primary source material eventually dries up, inevitably other bioenergy crops, genetically engineered trees, or wild forests will be tapped to feed the hungry facility. Just as likely is that the invasive culling would create “a transportation infrastructure associated with harvest and use for bioenergy, which will undoubtedly increase the pathways for spread into other areas.”

Genetic engineering is becoming increasingly inseparable from the development of bioenergy crops, because of industry’s desire for “increasing yield; enhancing nitrogen-use efficiency; and increasing resistance to conditions such as droughts, cold temperatures, pests, and diseases.” The manipulation of a plant or tree’s DNA raises even more questions as to the potential harm it could inflict on the natural world were it to go feral.

The spread of invasive plants will only worsen as the climate crisis progresses. The NWF report points out how invasives may actually have a “competitive advantage in systems disturbed by extreme events such as floods, droughts, hurricanes, and wildfires.” Warmer winters may also act as a perfect opportunity for “potentially invasive plants to thrive where they may not have in the past.”

Growing Risk catalogs some of the leading contenders for an unprecedented cultivation of bioenergy crops in the US. In 2011, the USDA permitted “field trials” by biotech giant ArborGen to plant 260,000 genetically engineered (GE) cold hardy eucalyptus trees across seven southern states. The report authors worry about the “transfer of the cold-tolerance gene to non-sterile varieties of eucalyptus,” which could take over ecosystems, increasing the risk of forest fires through their high oil content, and causing “serious hydrological impacts, including altered groundwater levels and/or stream flow, which could potentially impact aquatic and terrestrial species.”

The international Stop GE Trees Campaign, which has vociferously opposed the USDA “field trials,” warns that the next step for the industry is wide-scale commercial cultivation—which would virtually ensure the loosing of the manipulated eucalyptus into native ecosystems.  

Algae is “one of the fastest growing fields in biofuels research,” including microalgae (cyanobacteria) and macroalgae (seaweeds). As it stands now, “thousands of species of algae, and both native and non-native algae species are being considered as biomass feedstocks in the United States.” Genetic engineering is likely to accompany algae cultivation, as well.

Growing Risk highlights the fact that “little research has been conducted on potential” for algae to infect aquatic ecosystems and that “the potential impacts on biodiversity are not well understood.” If algae establishes itself in the wild, “the impacts on biological diversity, and particularly on aquatic habitats, could be devastating.”

Another popular bioenergy prospect is Giant reed, also known as giant cane or Arundo donax, a “large, fast-growing grass species native to India” that can skyrocket up to thirty feet tall. Arundo donax was originally introduced into the US in the 1800’s for erosion control and as a windbreak for agricultural fields, but has since become a “nuisance weed,” listed as one of the world’s 100 worst weeds. Giant reed’s requirement for vast amounts of water make it likely to “invade riverbanks, riparian areas, and floodplains, competing for scarce water supplies.”

The Surry County Board of Commissioners in North Carolina passed a resolution in October 2012 requesting that the North Carolina Department of Agriculture “declare Arundo Grass a noxious invasive weed, banning and restricting the planting thereof in the State of North Carolina.”

The biomass industry is considering several species of Miscanthus grass for mass cultivation due to its “ability to thrive on marginal, non-crop lands and their fast growth rates.” Certain traits make Miscanthus an “ideal invasive weed—it has the ability to resprout from below the ground, it grows rapidly, and it has efficient photosynthetic pathways,” according to the report.

While most Miscanthus is sterile, researchers are currently testing a form of giant Miscanthus with fertile seed, with experiments already demonstrating that seeds can travel for 400 meters. Miscanthus is a prime candidate to “displace native grasses and dominate roadsides and pastures, likely because of its ability to tolerate harsh conditions such as poor soils, cold temperatures, and shade.”

Reed Canarygrass or Phalaris arundinacea, already rampant in forty-three states, is another bioenergy industry favorite—a plant that the University of Vermont has described as “one of the most noxious invasive species in North American wetlands, rivers, and lakes.” Reed Canarygrass can take over “wetlands and disturbed areas, outcompeting native species…clogging shallow streams and ditches, and even impeding water flow.”

Napiergrass, or elephant grass, is another contender in NWF’s Most Likely to Invade category. A native of Africa, this species was encouraged by the US Bureau of Reclamation as a forage crop after it was brought to Texas and Florida in the 1900’s, and has since become “one of world’s most problematic weeds.” Napiergrass grows so densely that native species of grass, herbs and trees can’t compete, reducing freshwater flows and even blocking transportation canals.

Growing Risk: Addressing the Invasive Potential of Bioenergy Feedstocks asks the question of bioenergy crops that must be asked of all forms of industrial-scale biomass energy: will it do more harm than good?