White-tailed deer (Odocoileus virginianus) herbivory in Northeastern Ohio riparian zones : a preference study

Abstract

The objective of this study was to determine white-tailed deer (Odocoileus virginianus) browsing preferences for tree and shrub species in riparian zones of Northeastern Ohio. A total of five sites were selected along the Grand River and Pymatuning Creek in Trumbull County, and along the Cuyahoga River in Geauga County. In autumn of 2012, three to five 12 x 20 m quadrats were established in a stratified random fashion at each site, and the canopy species composition was surveyed for each quadrat. For individual tree species that had foliage accessible to white-tailed, deer the following data were recorded quantitatively and/or categorically: total available browse, type of available browse, and severity of browsing. The shrub and sapling layer was also surveyed within two randomly placed 4x4 m nested plots per 12x20 m overstory quadrat. The Jacob's Electivity Index was used to assess browsing preferences for tree and shrub species. As determined by the Jacob's Electivity Index various tree and shrub species: 1) were consistently avoided at all quadrats when present (bitternut and shagbark hickories, swamp and black ashes, black cherry, American basswood, and American elm), 2) were consistently selected in all quadrats where present (American hornbeam and black willow), or 3) varied widely in their selection by deer (silver and sugar maples). Quadrats containing sugar and, especially, silver maple with epicormic sprouts had greatest total browsing impact. Results suggest that white-tailed deer herbivory may actually reflect a Marginal Value Theorem model dictated by patches abundant in such sprouts. Further research is needed to determine potential effects of white-tailed deer in hindering the regeneration of such flood and/or beaver damaged vegetation in Northeastern Ohio riparian zones.