Alternative biomass strategies for bioenergy: implications for bird communities across the southeastern United States

Concerns over energy demands and climate change has led the United States to set ambitious targets for bioenergyproduction in the coming decades. The southeastern U.S. has had a recent increase in biomass woody pellet production and is projected to produce a large portion of the nation's cellulosic biofuels. We conducted a large-scale, systematic comparison of potential impacts of two types of bioenergyfeedstocks–corn (Zea mays) and pine (Pinus spp.)–on bird communities across the southeastern U.S. In addition, we evaluated three biomass alternatives for woody biomass from pine plantations: thinning, residue harvest, and short- rotation energyplantations (SREPs). We conducted transect counts for birds in eight different land-uses across the region (85 sites), including corn fields, reference and plantation forests, 2013-2015. We then used hierarchical occupancy models to test the effect of these biomass alternatives on 31 species. Across all species, birds had lower rates of occupancy in corn fields compared to pine stands. Thinning had positive effects on the average occupancy across species, while residue harvest and the potential conversion of conventional plantations to SREPs had negative effects. Cavity nesters and species with bark-gleaning foraging strategies tended to show the strongest responses. These results highlight the potential negative effects of corn as an energy croprelative to the use of pine biomass. In addition, harvesting biomass via thinning was a bird-friendly harvest method in comparison to other alternatives. While SREPs may negatively impact some bird species, previously reported yields emphasize that they may provide an order of magnitude greater yield per unit area than other alternatives considered, such that this land-use practice may be an important alternative to minimize the bioenergyimpacts across the landscape. This article is protected by copyright. All rights reserved.