Biofuel management has limited effects on forest nutrients and avian resource assimilation

Abstract

Intercropping switchgrass (Panicum virgatum), within managed loblolly pine (Pinus taeda) stands, has been proposed as an alternative source from which to create biofuels while also supporting wildlife biodiversity. However, little evidence is available on which to gauge if this practice affects nutrient availability and/or wildlife diets within pine stands. This study compares total carbon (C), total nitrogen (N), and C:N ratios in loblolly pine and blackberry (Rubus spp.) located in intercropped loblolly stands, including those managed with herbicides for hardwood control. This study also used stable isotopes (12C and 13C) to compare diet of an early successional bird species (yellow-breasted chat [Icteria virens]) in intercropped loblolly stands and loblolly stands managed with herbicides for hardwood control. Results indicate intercropping does not influence total C or N in loblolly or blackberry samples, although total N is elevated among blackberry samples in hardwood control loblolly stands. Results also illustrate that intercropping increases the ratio of 13C: 12C (δ13C) in yellow-breasted chat associated with areas where intercropping has been undertaken. Our study demonstrates that biofuel cultivation can affect nutrient flow within managed forest ecosystems. The influence of this nutrient flow should be considered when implementing biofuel production goals.