Impact of herbivory of white-tailed deer (Odocoileus virginianus) on plant community composition

The woodland ground flora of permanent quadrats in dry, wet and mesic habitats in Rondeau Provincial Park, Ontario, Canada was recorded in 1992. This park is a premier example of Carolinian or deciduous forest, but is heavily grazed and browsed by white-tailed deer (Odocoileus virginianus) . Within each habitat type there were both grazed and year-old fenced plots. In addition, the flora was recorded in 14-year old deer exclosures in the woodland. The long-term ungrazed plots contained greater amounts of species characteristic of Carolinian woodland (e.g. Arisaema triphyllum and Trillium grandiflorum), whereas the grazed plots had higher levels of invasive weeds (e.g. Stellaria media and Berberis thunbergii ). These data provide a baseline against which recovery of ground flora may be assessed following the herd reduction which took place in winter 1993 . Over-grazing by deer is a problem also found in southern English woodlands where roe, fallow, muntjac and sika deer numbers have increased in recent years.