Environmental Engineering Reference
In-Depth Information
FIGure 6.1
An oil palm (
Elaeis
spp.) plantation established on former rainforest land. (Courtesy of Rhett
Butler.)
Searchinger et al. 2008). Currently, most corn is grown for food for people or livestock using
well-established cropping systems. The challenge for biodiversity is that like many monocul-
ture systems, cornfields provide little or no habitat for other species. However, some “monocul-
tures” such as plantation forests may provide habitat for numerous understory plants and animals
(Brockerhoff et al. 2008).
Humans have appropriated approximately 37% of the terrestrial habitats on the planet for food
production, and an estimated 10
9
ha of additional land will need to be put into production by 2050
to meet the anticipated 50% increase in food demand as the world population grows and economic
development raises the standard of living of many countries (Vitousek et al. 1997). Of all forms
of human land use responsible for species listing under the U.S. Endangered Species Act, modern
agriculture ranks number one with 38% of species listed as a result of habitat loss to agriculture
(Stein et al. 2000). Clearly, any expansion of agriculture at the expense of natural habitat will
negatively affect biodiversity. Society expects clean water, fertile soils, food, fiber, nutrient cycling,
and aesthetics from the planet's soils and waters. A new service is being added: fuel for electricity
and transportation. It is therefore not surprising that ecologists were among the first to recognize
that in addition to the potential benefits of bioenergy, its expansion also had great potential to
harm ecosystems, habitats, and species (Hill et al. 2006, 2007; Tilman et al. 2006; Fargione et al.
2008, 2009; Searchinger et al. 2008; Flaspohler et al. 2009; Malakoff 2009). In fact, we believe
that land-use changes associated with a worldwide expansion of some bioenergy production sys-
tems are amongst the greatest current threats to biodiversity. The degree of this threat will be a
function of the form that bioenergy production takes on the landscape. In short, any replacement
of diverse native habitats with traditional agronomic monocultures will represent a loss of biodi-
versity and some associated ecosystem services. However, there are several promising alternatives
to unsustainable models that could allow bioenergy production and a functioning ecosystem to
coexist. In fact, there are opportunities for win-win scenarios in which biofuel production can
benefit biodiversity conservation. Another important consideration in gauging bioenergy effects
on ecosystems is the type of habitat (e.g., native diverse vs. non-native simplified) being displaced
by expanding bioenergy plantings.
