One of the largest and possibly most damaging effects of growing biofuel crops is changing the landscape from either a grassland or a former farm into a biofuel farm. As of now, many of the sites selected for future biofuel crop growing are marginal lands that are not productive enough for traditional agriculture. That means these lands have high erosion potential, shallow soils, poor drainage, and are located in less suitable climates (Wright, 2013). Growing biofuel crops in these areas risk inducing more negative impacts via exacerbation of pre-existing conditions (as listed above), eventually leading to decreased crop yields, diminished primary productivity, and reduced carbon sequestration (Wright, 2013).
Habitat Loss
Many biofuels are set to be grown in temperate grasslands – globally the most altered and least protected ecosystem. These grasslands provide vital habitat for already-threatened, rapidly declining nesting bird populations. (Wright, 2013). As the grasslands are converted, these birds lose more habitat and are pushed into smaller and smaller segments of land. These effects are intensified if harvesting occurs in the autumn or winter, as extraction of the biofuel crops reduces winter cover for many different species - assuming they are still living in the area (Wright, 2013).
More Production
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| Photo credit: Hoffman, 2009 |
Overall, growing biofuel crops puts more land into active production, and additional agriculture is always closely followed with increased erosion and fertilization. Fertilizer in particular results in higher, denser growth of the biofuel crops. The resulting increase in herbicide use to control weed population decreases the amount of forbs, and reduces nesting opportunities for native birds (Wright, 2013). Further, additional agricultural acreage - and specifically the irrigation that accompanies it - puts even more strain on already limited water supplies (Barney, 2010).
Possible Benefits
There has been some debate over whether biofuel crops will, in fact, cause more harm to the environment than good. It has been suggested that switchgrass, a particularly productive potential biofuel crop provides a lot of biomass per unit area, is good habitat for grassland birds, and grows well enough in marginalized lands that it would need limited fertilizer and management. It has also been said that switching from row crops (like corn) to some biofuel crops (like switchgrass) can decrease erosion and increase habitat, though switching from grassland to biofuels has been linked to increases in peak stream flows and greater flood risks (Bies, 2006; Wright, 2013). Based on this data, benefits seem to be intricately tied to the current use or non-use of the land.
UNINTENDED EFFECTS
Risk of Invasive Spread
Biofuels are generally selected because they are maximally productive on marginal lands. This means they establish easily, are highly competitive, and thrive with minimal human intervention (Barney, 2010). Of the plants that satisfy those requirements, the most promising potential crops are perennial rhizomatous grasses like switchgrass, because they exhibit all the qualities listed above, as well as tolerance of poor growing conditions and less-than-ideal climates, rapid growth rates, and they harbor few pests (Barney, 2010). Unfortunately, these plants are also some of the United States’ worst invasive species, and indicate a high likelihood of invasion and dominance of target cropping regions. This means there is a good chance that the grasses will grow beyond the cultivated environment and become pests in outlying regions, so consistent, holistic, and intelligent management practices will likely prove to be essential to biofuel crop production.
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| Original Figure, stats from Biofuels Make a Comeback Despite Tough Economy, 2011 |
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