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Harvest as a Habitat Management Tool Aldo Leopold (1933) asserted that game can be “restored” by hunting. Our primary emphasis in this chapter is use of hunting as a tool to maintain deer densities within carrying capacity of the habitat. Maintaining deer populations within carrying capacity allows the most preferred plant species in the habitat to reproduce, affords maximum protection to other resources, and benefits all organisms in an ecosystem. We recommend managing populations based on our forage-based definition of carrying capacity, which results in densities lower than K-carrying capacity, commonly used as the basis for modeling deer population growth and harvest management. Much of the theory underlying harvest management, including the concepts of density dependence, density independence , and compensatory mortality, is based on K-carrying capacity. Density dependence is an important idea in harvest management because it is the basis for the concepts of compensatory mortality and maximum sustainable yield (White and Bartmann 1997). Dynamics of density-dependent populations of white-tailed deer are driven by environmental factors such as competition for forage or predation (Bailey 1984). Density-dependent factors regulate population size. In density-dependent populations, mortality increases or births decrease as population density increases. A reduction in population density may result in lower mortality and more births, depending on how far from K-carrying capacity the population is. Predation or harvest by humans may limit deer population growth and maintain populations at a relatively stable level over time. Density-dependent populations may respond to predator removal and lack of harvest by increasing exponentially from low density up to a peak, suddenly crash to a The Gun: Harvest and Management Planning K e y C o n c e p t s ▼ Maintaining deer populations within the carrying capacity of the habitat should be the primary goal of harvest management. ▼ Management decisions regarding whether deer numbers exceed or are below carrying capacity of the habitat are best made by monitoring utilization of key deer forages and monitoring trends in deer body mass, antler development, and fawn survival. ▼ Establishment of a management goal is important, whether managing for trophy males or for maximum-sustainable-yield harvest. ▼ Developing a sound management plan and keeping records of the number, age, sex, body mass, and antler dimensions of harvested deer are important aids in meeting management objectives. 8 228 chapter 8 ▼ lower level because resources have been depleted, and then begin the cycle of gradually building up again (Saether 1997). Damage to forage plants and soil resources could occur during the phase of exponential population increase. White-tailed deer are ecological dominants (keystone species) in ecosystems where they occur and therefore may negatively affect many other wildlife species during exponential population growth. Removal of predators followed by an increase in ungulate populations could trigger what is called a “trophic cascade.” Increased ungulate populations may damage vegetation by excessive utilization, resulting in changes in composition of the plant communities. Excessive use by deer may, for example , shift plant community composition from dominance by woody plants and forbs to grasses and grasslikes (Rooney 2009). Forbs and shrubs preferred by deer may be replaced by plants that are not consumed. Damage to vegetation could negatively impact other wildlife species. For example, damage to understory shrubs by excessive deer browsing may result in reduced songbird populations (McShea and Rappole 2000). High densities of deer caused changes in plant communities in Pennsylvania, resulting in reduced insect and bird density thirty years later (Nuttle et al. 2011). Harvest by humans may not be essential for deer populations to remain in a stable equilibrium with food resources when natural regulatory mechanisms such as predation are functioning (Saether 1997; Ballard et al. 2001). Humans have removed natural constraints to deer population growth in many areas by removing large predators. Reintroduction of black bears, wolves, and large cats in areas occupied by white-tailed deer, particularly in areas with large human populations, is often economically and politically unfeasible. The concept of compensatory mortality is that increased food availability and improved nutrition resulting from reduced population density results in increased survival of remaining individuals in the population (Mackie et al. 1990). The increase in survival compensates for individuals lost. Compensatory mortality does not occur and harvest is not necessary as a population -control mechanism to maintain deer densities within carrying capacity of the habitat where deer populations are not density dependent. Harvest may be additive, rather than compensatory, in density-independent deer populations. Mortality and births do not increase or...

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