Use of common forest forbs to measure browsing pressure by white-tailed deer (Odocoileus virginianus Zimmerman) in Virginia, USA

The effect of browsing by white-tailed deer (Odocoileus virginianus Zimmerman) on reproductive activity of five understory plant taxa was examined using two deer exclosures in the Blue Ridge Mountains of Virginia, USA. Surveys were conducted within and outside of deer exclosures using 250-m² strip transects. Uvularia L. spp., Smilacina Desf. spp., Polygonatum Mill. spp., Orchis spectabilis L., and Arisaema triphyllum (L.) Schott were identified and counted, and noted for reproductive activity (presence of flowering and/or fruiting plants). Smilacina and Uvularia had more plants inside than outside of exclosures, whereas no significant differences in abundance were recorded for the other taxa. Reproductive activity of all taxa observed was greater inside than outside of exclosures. The survey method was field tested by determining the abundance and percent of plants reproductive at 11 sites along the Blue Ridge. Reproductive activity, for all taxa, was negatively correlated with deer abundance. This study demonstrates the potential for deer herbivory to affect herbaceous plant community composition and indicates that a measure of reproductive activity in common forest forbs would provide a rapid means to measure the severity of deer browsing on herbaceous species.