Cooperative Fish and Wildlife Research Units Program: Mississippi
Education, Research and Technical Assistance for Managing Our Natural Resources

Loman, Z. G., S. K. Riffell, B. R. Wheat, D. A. Miller, J. A. Martin, and F. J. Vilella. 2014 Bird community response to establishing intercropped switchgrass in intensively-managed pine stands. Global Change Biology Bioenergy 67:201-211.


Increased demand for renewable fuels has led to innovations in alternative biomass production regimes. Intercropping switchgrass (Panicum virgatum L) between rows of young pine (Pinus spp.) plantations is a potential method to generate lignocellulosic biofuel feedstocks within intensively managed forests. Intensively managed pine supports a diverse avian assemblage. Establishment and maintenance of an annual biomass feedstock likely affects these bird communities via changes in plant communities, dead wood resources, and habitat structure. Therefore, we sought to understand how establishing switchgrass affects bird communities within intercropped loblolly pine (Pinus taeda L.) plantations as compared to typical intensively managed loblolly pine forest on an operational-scale. We conducted point counts using distance sampling for three years following establishment of intercropped switchgrass stands, traditionally-managed pine plantations (control), and switchgrass-only plots (10 ha minimum each) in Kemper Co., MS. We detected 59 breeding birds species from 11,195 detections from 6 treatment replicates. Early successional species used intercropped plots less than plots managed traditionally for 2 years after initial establishment activities, but avian communities and total avian conservation value converged during year three. Neotropical migrants and forest-edge associated species were less abundant in intercropped plots than controls during the first two years after establishment and more abundant in year three. Short distance migrants were scarce in both intercropped and experimental plots initially, were less abundant in intercropped plots in year two, and converged in year three. Species associated with pine-grass habitat structure were less abundant initially in intercropped plots, but converged more quickly with controls. Switchgrass monocultures planted within a managed pine forest provided minimal resources for birds. If songbird conservations is a management priority, managers should consider potential reductions of some breeding birds for one to two years following intercropping. It is unclear how these relationships may change as stands age and outside the breeding season.