Deer Management for Forest Health--an MCA Priority

The Metrowest Conservation Alliance (MCA) is concerned about the detrimental impacts that overabundant deer populations can have on our forests and public health.

Extensive scientific evidence demonstrates that high deer densities severely degrade habitat on conservation lands through excessive browsing. Deer overbrowsing stunts forest regeneration by eliminating tree saplings, reduces plant diversity, endangers native plant species, tends to increase abundance of invasive plants, eliminates ground and shrub bird nesting habitat, and can have long-term negative consequences on soil and vegetation.

We are not only losing the next generation of our forests. We are also increasing potential areas for invasive plant species to invade, and we are losing the needed ecological services a diverse herbaceous and shrub understory provides.

High deer densities contribute to a higher incidence of deer-car collisions and a greater incidence of tick-borne illnesses, such as Lyme disease. When deer populations are high, we tend to see a high abundance of the invasive plant, Japanese barberry, which is an ideal habitat for white-footed mice and the deer ticks they carry (both carriers of Lyme disease). Thus, forests with more barberry in the understory tend to have higher prevalence of deer ticks and potentially Lyme disease.

Additionally, the deer can suffer when the landscape is not able to provide enough food for a large deer population. When preferred food is scarce, deer resort to eating vegetation that they typically would not, which can increase the rate of malnutrition, starvation, and disease within the deer population (e.g. Chronic Wasting Disease).

Currently, deer densities in the MCA area are conservatively estimated to be from 10 to 40 deer per square mile, whereas MassWildlife recommends a target density of 12-18 deer per square mile in zone 9 (western part of the watershed) and 10 (eastern part of the watershed, including Carlisle). These levels are based on the land’s carrying capacity (how many deer the land can support while maintaining a functional ecological balance), and the point where the rate of conflicts with humans typically decreases.

A successful deer management program will reduce the deer population to a sustainable level where forest understories will be able to develop, and wildlife and plant biodiversity will increase. We anticipate that this will also reduce deer-car collisions and tick-borne illnesses.

CURRENT EFFORTS

Examples of Management in the Region
  • The Town of Boxborough worked to lessen the severity of its "no firearms" by-law and was successful in doing away with the by-law altogether. Since then the town has seen a significant decrease in mating doe to deer populations.
  • The Town of Weston has created a "Deer Management Toolkit."
  • Several towns and cities now have deer hunting programs: Berlin, Boxborough, Carlisle, Dover, Framingham, Harvard, Sherborn,Sudbury, Westborough, Weston
  • Hunting is also legal on private property (where allowed), as well as on MassWildlife, National Wildlife Refuge, and some Department of Conservation and Recreation lands.
  • SVT created a Toolkit similar to Weston's but for Land Trusts. SVT allows hunting on specific properties by permit only.

RESOURCES

   General Resources
   Quabbin Reservoir Research
   Weston-specific Examples
Deer Overabundance, compiled by Thomas J. Rawinski, USDA Forest Service, Durham, NH (March, 2013)