Goat browse selectivity during conservation grazing in an invaded eastern oak-hickory forest.

Oak and hickory (Quercus spp. and Carya spp.) recruitment in forests of eastern North America is adversely impacted by woody invasive species. Conservation grazing, the use of livestock for restoration or biodiversity promotion, has been used to control invasive plants. The efficacy of such grazing and its ecological tradeoffs in oak-hickory forests, however, is unknown. We aimed to fill this gap by investigating browsing intake and preference by goats. To support this, nineteen experimental plots were established in an invaded forest, and their species composition and biomass quantified. Twelve plots were browsed under high (1019 goat-days ha⁻¹) and low (509 goat-days ha⁻¹) browsing pressure regimes with direct observations of forage intake and selection. Leaves of commonly browsed species were assessed for nutritional composition. Goats generally selected for native spicebush (Lindera benzoin) over invasive multiflora rose (Rosa multiflora), however, selection of the latter increased with time. Both species identity and browsing pressure were good predictors of browse intake. For greater biomass reduction of invasive species, the use of high browsing pressure is recommended. This research showed that conservation grazing can be an effective tool to reduce biomass of invasive species such as multiflora rose, privet (Ligustrum spp.), and oriental bittersweet (Celastrus orbiculatus) in oak-hickory forests when high browsing pressure is implemented, nevertheless goats may initially target their preferred species (e.g., spicebush). [ABSTRACT FROM AUTHOR]