Trade-offs between biofuel production, agricultural production, and conservation of biodiversity

Background/Question/Methods

Growing energy demands and concerns for climate change have pushed forward the time line for biofuel production. However, the effect of large-scale biofuel production in the U.S. on the agricultural industry, that is primarily responsible for food production and livestock feed, and on species diversity of many taxa (amphibians, birds, mammals, and reptiles) remains unclear. This study presents the first quantitative analysis of these trade-offs in the face of climate change. Switchgrass (Panicum virgatum L.) is a promising candidate for cellulosic feedstock production.  Current and future (2080-2090) switchgrass productivity was estimated across the central and eastern U.S. using ALMANAC, a mechanistic model that simulates plant growth over time.  Locations that minimize the impact on species diversity of all four taxa groups and minimize the proportion of agricultural and forested areas converted, while maximizing biomass production, were identified using a spatial optimization algorithm.

Results/Conclusions

Under current climate conditions, regions for switchgrass biomass production that have a small effect on agriculture and biodiversity are located primarily in Louisiana, southern Florida, Nebraska, and South Dakota.  By 2080-2090 under the SRES B2 and A2 scenarios, the only regions that still fulfill these conditions are located in Nebraska and South Dakota.  In order to minimize land conversion and loss of biodiversity, suitable areas for current and future climate change should be targeted for their long-term growth potential. The trade-offs between these three forces requires additional farmland (+25%) to meet biofuel production demands as opposed to planting regions with the highest predicted biomass potential. The regions selected for switchgrass production change dramatically when only considering the impact on either agriculture or biodiversity. Large-scale switchgrass production will impact the diversity of mammals and birds the most when conservation of biodiversity is not considered.  Biofuel production has many potential impacts.  This study provides a useful framework to analyze the effect of biofuel production on many other factors such as greenhouse gas emissions, soil erosion, nutrient loss, and water quality.