Intercropping switchgrass with loblolly pine does not influence the functional role of the white-footed mouse (Peromyscus leucopus)

• Published in: Biomass & bioenergy 2013-07, Vol.54, p.191-200
• Main Authors: Briones, Kim M., Homyack, Jessica A., Miller, Darren A., Kalcounis-Rueppell, Matina C.
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biofuel production; Biofuels; Biological and medical sciences; Biotechnology; Carbon; Energy; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Generalities. Agricultural and farming systems. Agricultural development; Generalities. Production, biomass, yield. Quality; Industrial applications and implications. Economical aspects; Intercropping; Nitrogen; Panicum virgatum; Peromyscus leucopus; Pinus taeda; Stable-isotopes; Trophic position
• ISSN: 0961-9534; 1873-2909
• DOI: 10.1016/j.biombioe.2013.03.033

Intercropping biofuel feedstocks in managed forests of the southeastern United States is a potentially sustainable source of renewable energy. Ecological effects of energy crops in forests are poorly understood, and it is unknown whether the ecological role of native rodents is influenced by alternative food resources. Therefore, we used a stable isotope analysis to compare diet and trophic responses of white-footed mice (Peromyscus leucopus) in 1) plots where switchgrass (Panicum virgatum), a C4 plant, was intercropped with loblolly pine (Pinus taeda), a C3 plant, 2) plots of loblolly pine, and 3) plots of monocropped switchgrass. We collected fur from live-trapped rodents and potential dietary sources in 2010. We predicted δ13C and δ15N values of mice in switchgrass plots would reflect a C4-based, granivorous, diet if there was an effect of intercropping on the functional role of mice. Del13C values of mouse fur in monocropped switchgrass, but not intercropped switchgrass plots, shifted more toward a C4 signal. However, δ15N values indicated that mice remained functionally omnivorous across treatments. Our results were supported by isotope values from invertebrates across guilds. Diet and trophic position of white-footed mice was not influenced by intercropping switchgrass in pine plantations indicating they maintained their functional role in this biofuels management regime. Future research should focus on individual and population responses of rodents to altered vegetation structure where biofuels feedstocks are grown and indirect effects on inter- and intra-species interactions. •We examined carbon source and trophic position of mice in pine × switchgrass intercropped forests.•The δ13C values of mice in intercropped plots did not differ from control plots.•The δ15N values of mice in intercropped plots did not differ among treatment plots.•Plant and invertebrate δ13C and δ15N values were as expected, and supported our mouse results.•Intercropping switchgrass and pine does not change the functional role of mice.