Biofuels for biodiversity: choosing the right path

Michael W. Palmer, Oklahoma State University

(Click here for a draft presentation on this subject)

(Click here for a list of Oklahoma scholars interested in sustainable biofuels)

A Biofuels Future

The earth’s climate is changing. We are running out of fossil fuels. Dependence on foreign oil is jeopardizing our national security. These issues weight heavily on the public and policy makers alike. Proposed solutions have been viewed as impractical or ineffective. In these early years of the 21 st century, however, biofuels (conversion of plant or animal material into fuel such as ethanol) seem especially promising and practical. The question remains: Will we get it right?

Concerns about Biofuel Crops

Most of the current interest in biofuels revolves around the use of old crops (such as crops) or new crops (such as switchgrass). For example, the California company Ceres is genetically modifying switchgrass, and claims “ You could turn Oklahoma into an OPEC member by converting all its farmland to switch grass”. However, there are serious concerns with this agrotechnological approach:

  • Plowing, planting, and nitrogen fixation are all extremely energy-intensive, thus decreasing energy gains.
  • Turning the soil enhances soil respiration – thus releasing extra carbon dioxide into the atmosphere and enhancing the greenhouse effect.
  • Clearing of environmentally sensitive areas (such as Amazonia) for biofuel crops would reduce biodiversity.
  • Increasing fuel crops may adversely affect food production.
  • New crops may become invasive.
  • Genetically modified fuel crops will be difficult to contain. For example, switchgrass naturally occurs in abundance in the majority of US states, and would easily cross-pollinate with transgenic switchgrass.
  • Pesticide use is typically high on single-species crops (monocultures), with adverse effects on biodiversity and human health.
  • Monocultures are unstable and unpredictable in the face of fluctuations in weather and pests.
  • Monocultures are prone to diseases.
  • Nitrogen use efficiency and water use efficiency are typically low.
  • New crops such as switchgrass have evolved in species mixtures, and are unlikely to prosper in monocultures.

 

 

Concerns about loss of grasslands

Throughout much of North American and the rest of the world, grasslands are disappearing – either due to development or abandonment. This has created economic, environmental, and safety problems:

  • Biodiversity declines in many grasslands that are unmowed, unburnt, or ungrazed. This is because the species have evolved under conditions where biomass is regularly removed.
  • Loss of such grasslands is affecting the beauty of our landscape, in addition to our natural and cultural heritage.
  • Many unmanaged grasslands are rendered near useless by invading species. In the southern Great Plains, eastern red cedar has become a major allergy problem. Its extreme flammability has made it a major public safety problem.

 

Proposal: using grasslands for biofuels

Natural or restored grasslands have numerous advantages as a source of biofuel feedstock, including:

  • As native hay meadows are a traditional form of land management, there is already a production infrastructure in place.
  • Biological diversity can remain high.
  • Hay meadows have multiple uses, including for biodiversity conservation, livestock, and honey production.
  • The native species are already adapted to local climates, obviating the need for genetic manipulation.
  • No tilling means less soil respiration.
  • Fertilizer, watering, and pesticides can be minimized, thus decreasing energy inputs and environmental damage.
  • Complete crop failures are unlikely in species mixtures.
  • The presence of legumes can allow natural nitrogen fixation, enhancing yield with little cost.
  • Regular cutting will prevent invasion by woody plants and associated environmental degradation.
  • Vegetation scientists already know a great deal about the ecology and productive capacity of grasslands.

While there is clearly no ‘magic bullet’ for our global energy conundrum, it is imperative that we not create new problems when a big part of the solution is under our feet.