Appetite for trouble
Wisconsin Natural Resources Magazine, Oct 2007
Even small numbers of deer can have dramatic consequences where the land can’t support a larger herd. At a deer density of 12 to 15 animals per square mile of range, herbaceous plants like trillium, Indian cucumber, showy lady’s slipper and white fringed orchid decline. When deer densities reach 20 to 25 animals per square, species like pines, white cedar, hemlock, oaks and Canada yew can stop regenerating and small mammals like red-backed voles, an important prey species, starve out without the forest floor vegetation they need. At 25 to 35 animals per square mile of range, birds like hooded warblers decline from lack of needed ground, shrub and tree layers.