White-tailed Deer in National Parksby Michael A. Coffey, Wildlife Biologist, Natural Resources Management Division |
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Why are so many deer in some areas?
White-tailed deer occur throughout the contiguous United States except in some parts of the Southwest. Nationwide, deer populations have increased from between 350,000 and 500,000 in the early 1900s to an estimated 24 million in 1999. Since the late 1950s, the densities of white-tailed deer in the eastern United States have increased to levels that are probably higher than they have ever been. The distribution too seems to have changed drastically across the species' former range. Scientists believe that the increased density and the shift in distribution are attributable to large-scale changes in land use. For example, logging and the conversion of forested lands into agricultural, suburban, and other types of developed landscapes created favorable deer habitat with year-round, reliable food sources that allow deer populations to flourish. The enhancement and expansion of deer habitat was accompanied by a decrease in historical controls of deer population growth. Unlike the deer, their predators such as the wolf (Canis lupus), mountain lion (Felis concolor), and bobcat (Lynx rufus) did not adapt to the habitat changes or were extirpated in most of the eastern United States. The effect of sport hunters on deer populations also lessened as hunting seasons, bag limits, and land available for public hunting became restricted and the popularity of hunting declined.
Why are so many deer in and around national parks? Aren't they hunted?
Many parks annually survey their deer populations by various scientific methods to track population-size trends. National parks, particularly in the eastern and Midwestern United States, have documented increasing deer populations. Deer are not hunted in most eastern parks because hunting is permitted only where specifically authorized by a park's legislation. Sport hunting is authorized by law in all national preserves and in 69 recreation areas, seashores, lakeshores, and some other National Park System units . Delaware Water Gap National Recreation Area, New River Gorge National River, and Cape Cod National Seashore are some eastern units where hunting is permitted. Many eastern units are small land parcels (<10,000 acres) that are often of historic importance and surrounded by residential areas, highways, and small farms. Hunting is usually not permitted or is restricted on much of the private land around small eastern parks. Furthermore, much of the area is not suitable for hunting because of public safety.
Do large numbers of deer affect park visitors or resources?
Many park visitors travel to national parks to see wildlife, especially deer. In some parks, however, the densities of deer have created problems. For example, deer have become accustomed to visitors, come in close contact with people, and have injured people who perceived the animals as being tame. Of major concern are collisions of vehicles with deer on some park roads. Large numbers of deer in parks also cause intensive browsing on tree seedlings, crops, and ornamental vegetation. Certain parks have installed fences to exclude deer from some areas and are studying the effects of deer browsing on park vegetation.
If deer harm park resources, why don't park managers take action?
Park managers must comply with laws, policies, and regulations that govern natural and cultural resource management in the National Park Service to decide whether deer-related effects warrant action. Policies are based on the National Park Service Organic Act of 1916 that established the various units, the National Environmental Policy Act (NEPA), and other laws enacted by the U.S. Congress. Resource management policies are aimed at providing present and future generations with the opportunity to enjoy and benefit from natural and cultural environments that evolve by biological and physical processes and are minimally influenced by human actions. In other words, management emphasis is on minimizing human effects on native animals and their natural population dynamics.
National Park Service policy allows the removal of some animals in some situations, for example, when:
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Are any parks managing deer?
Parks address deer-related concerns such as human health and safety, protection of threatened or endangered species, management of cultural landscapes by a variety of methods. Warning signs at crossroads, enforcement of lower speed limits, and trimmed vegetation along roadways to increase visibility are attempts to lower the number of collisions by vehicles with deer. Park visitors are educated about potential human injury by deer and adverse effects on the health of deer from hand feeding or petting the animals. Parks raise public awareness of the risk of encountering deer ticks in wooded habitat and counsel visitors in preventive measures. Threatened or endangered plant species are fenced to protect sensitive species from deer browsing.
Evidence of high deer densities or heavy vegetative browsing does not necessarily mean deer are causing unacceptable harm to park resources. Rather, park managers must determine that deer are impairing the park's ability to achieve management objectives and reach goals. Each park establishes goals that reflect the purpose of the park and direct management. Objectives are stepping-stones to a particular goal such as a specific condition that must be maintained or achieved.
What about deer management in Gettysburg National Military Park?
n Gettysburg National Military Park, browsing by deer impaired management of the park. This park is mandated to maintain the 1863 landscape of woodlots and crop fields that are important for understanding events during the Civil War. This goal requires survival of a sufficient number of seedlings to ensure perpetuation of the historic woodlots and annual maturity of crops representative of the historical period. By reviewing the literature and consulting forestry experts, park managers determined the specific number of seedlings for successful woodlot regeneration. They also determined the percentage of acceptable crop loss that was based on park management goals and objective pertaining to the historical landscape of the park. Studies revealed not only the extent of damage to cropfields and woodlots but browsing by deer as the cause of the damage. A comparison of the current condition of the crop fields and woodlots with the quantified desired condition showed that browsing by deer exceeded the acceptable damage. The park completed an environmental impact statement to determine the best control of deer browsing in that park.
Why are deer not managed in all parks where the densities of the animals is high?
Deer are not managed in all parks where their densities are high either because specific goals have not been identified and objectives of natural-resource management have not been quantified or because the parks lack scientific data on environmental conditions that suggest deer as the principal cause for not achieving those objectives. In Valley Forge National Historical Park deer are not managed because deer numbers and densities are not preventing the park from meeting the goals and objectives and purposes for which the park was established.
Some people believe heavy browsing causes irrevocable change to ecosystems. They feel that parks should prevent deer browsing even when compliance with mandates of parks are not impeded. Indeed, prolonged, intensive browsing by deer can reduce the number of plant species and cause plant species that deer do not eat to become the dominant vegetative species. Other wildlife that use such vegetation can thereby be deprived or favored. Astute determination of compliance or failure of compliance with mandates is therefore crucial to management of natural and cultural resources in a park.
What will be the future deer management in the National Park System?
Conflicts between deer and humans are of concern to state and other federal agencies and private communities. Many communities that experience social or managerial problems from high densities of deer have formed task forces or other groupings to address deer management. Members usually include representatives from local municipalities and townships, state departments of natural resources, federal agencies including the National Park Service, and other interested stakeholders. The approach of such community partnerships is the identification of the nature and extent of problems caused by deer and recommendations of regional solutions. Such an approach usually opens lines of communication, increases awareness by education in all sides of the issue, and seeks to acquire scientifically based solutions to a region's problems with deer.
Free-roaming white-tailed deer do not recognize physical or political boundaries. Therefore, community-based management decisions may be the best solution to conflicts.
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