Thursday, June 21, 2007

Biofuel Crops as Invasives? The Importance of Weighing the Risks and Benefits

Biofuel Crops as Invasives? The Importance of Weighing the Risks and Benefits

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You’ve probably heard of kudzu, a.k.a. “the vine that ate the South.” And if you’ve traveled in the South, you’ve likely seen how this monster overwhelms the landscape. But did you know that kudzu, which is native to Asia, was initially introduced on purpose, touted as a forage crop and a means of erosion control? If southerners knew then what they know now about kudzu, they would never have bought it.

The same can be said of landowners and stewards of natural areas in Illinois who bought the idea that exotic plants such as autumn olive, bush honeysuckle and multiflora rose could be safely introduced to improve the landscape of the Midwest. If we knew then what we know now, we wouldn’t have put entire ecosystems at risk by planting these exotic invaders. And we wouldn’t be spending millions of dollars at the state level each year—and billions nationally—to combat the problems associated with invasive plants.

Or would we?

In hindsight, we can see that our willingness to adopt exotic plants in attempts to solve ecological problems in the past was based on slipshod decision making. Policy makers and the public alike accepted claims about the supposed benefits of establishing nonnative plants without solid support. And we asked far too few questions about the potential costs—both economic and ecological—of such introductions.

Knowing what we know now about the catastrophic consequences of introducing the wrong plants, you would think we’d have adopted a rigorous process governing all large-scale plant introductions.

But that doesn’t seem to be the case when it comes to some of the plants now being investigated as potential biofuels, especially the perennial grasses, such as miscanthus. And in the current social and political climate, there’s so much pressure to develop biofuels that some scientists who study the ecology and management of invasive plant species are concerned we may be headed down the kudzu path all over again.

In a paper published last September [If you're logged into a computer on the UIUC campus or elsewhere with a subscription to Science online you can click here to open the paper in a new window], S. Raghu of the Illinois Natural History Survey and six colleagues from around the country call attention to how little serious analysis is being devoted to the potential consequences of cultivating nonnative grasses for biofuel. Indeed, they point out that six of the eight ecological traits identified as ideal for biomass energy crops are also traits that contribute to the potential for an introduced plant to become invasive. They further explain that it is nearly impossible to eradicate or even control invading grasses once they are established.

Raghu and colleagues acknowledge the potential benefits of introducing some plant species as sources of biofuel. But they call for a policy of first establishing the safety of such introductions by means of stringent agronomic and ecological analysis, the sort of up-front studies that are already required for other beneficial introductions, such as biological control agents and transgenic plants.

Perhaps the best way to think about whether the large-scale introduction of a given plant species makes sense would be to ask whether, or at what price, a person could buy insurance that would compensate for the damage that species might cause were it to become invasive. Without the answer to that question we don’t have enough information to develop sound policy.