Studies have found that at high densities, the amount of browsing done by deer can have detrimental effects on forest communities. Overbrowsing can eliminate understory herbaceous plants, shrubs, and saplings resulting in a forest with little but adult canopy trees. Native understory plants are a critical source of food and cover for other wildlife species in the forest. The loss of these plants can be very detrimental to these other species. Saplings represent the future canopy layer. As older trees die, saplings will grow up to replace them. Uncontrolled overbrowsing by deer can result in the failure of forest regeneration.
The removal of native plants from an ecosystem opens it up to invasion by exotic plants. Generally, deer do not browse these plants giving them a competitive advantage over native species. Once invasive plants get a foothold, they can quickly spread and overtake large expanses of habitat. Invasive plants provide little to no value to wildlife species in terms of food or cover quality. The removal of invasive plants over large areas requires enormous amounts of time, money, and manpower.
The primary goal of the MCPC's Deer Management Program is to manage the deer population in a way that promotes maximum biodiversity levels in the habitats under its care. In many parks, all evidence points to the fact that deer populations are still too high. In selected parks of this nature, the MCPC continues to work towards reducing populations to levels that will allow for successful habitat restoration, both natural and assisted. Other parks exhibit little damage from deer and contain lower density populations. In these parks, the goal is to maintain the deer population at levels that allow healthy habitats to continue to thrive. The MCPC requires hunters registered in the program to focus their harvest efforts on female deer. Since females can reach reproductive maturity at one year of age and generally produce two fawns each year, they can contribute the most to population growth.