A study described in the October issue of BioScience identifies diverse native prairie as holding promise for yielding bioenergy feedstocks while minimising harm to wildlife. Harvesting diverse prairie, which is dominated by perennial plants, could avoid adverse environmental effects associated with expanding cultivation of corn for ethanol, such as loss of wildlife habitat and high fertiliser runoff. It could also avoid the threat of invasion posed by cultivation of exotic biofuel crops.
The study, by Joseph E. Fargione of the Nature Conservancy and nine coauthors, explores how choices between a variety of current and emerging bioenergy feedstocks and production practices could affect wildlife as demand for biofuels increases. The growing US use of biofuels - so far, almost entirely ethanol made from corn - has contributed to a sharp reduction of the amount of grassland that landowners had enrolled in the Conservation Reserve Program. The conversion of grassland to corn cropland has most likely harmed grassland-dependent wildlife, and a congressional mandate to further step up biofuel production in coming years will add to this pressure.
Yet feedstocks for bioenergy (which includes biomass burning and gasification as well as liquid fuels) vary widely in their potential effects on wildlife. Because bioenergy requires relatively large amounts of land, the loss of wildlife habitat is of particular concern. Use of alternative feedstocks such as wastes, agricultural residues, and cover crops, as well as native perennials harvested in a way that is compatible with wildlife, could produce bioenergy with less-damaging consequences for wildlife. Cultivation of algae could also potentially yield bioenergy without loss of wildlife habitat. Fargione and his coauthors point out that detailed comparisons of yields from different feedstocks are urgently needed so that practical bioenergy strategies favourable to wildlife can be devised.