Wildlife Population Management

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Wildlife Population Management

Introduction

Wildlife population management refers to any strategy that seeks to maintain a target population at a level that can be supported by the ecosystem. This can involve protecting a threatened population from declining further in numbers, or even re-stocking a population. Conversely, when the numbers of a target population have become too great to be sustained by the food or territory available, then predators can be introduced, or a human-mediated cull can be done. Culls have also been done when an infectious disease is present in a population; the deliberate killing of the infected animals can help protect other members of the population as well as other species in the same habitat. Put another way, the management strategies focus on the habitats of the species of concern. Wildlife population management can also use the legal system to prosecute those found responsible for illegally hunting or trapping species.

Historical Background and Scientific Foundations

In the United States, there were few laws or regulations on the hunting of wild animals before 1900. Virtually all animal and bird species were hunted throughout the year.

Although regulations were introduced to control the timing of hunting of species for commercial purposes and to assign quotas on species killed, and, subsequently, similar controls on recreational hunting, various species came under threat from the changing land use in the country. Territory was lost as land was converted to agricultural, industrial, and urban uses. Furthermore, in agriculture-intensive states, predators such as foxes were actively hunted and killed, allowing their natural prey to increase tremendously in numbers.

By the mid-twentieth century, the need to more actively deal with wildlife populations had been recognized, and the discipline of wildlife biology had been created.

Successful wildlife population management adopts what is known as a landscape perspective. This view takes into account the biological diversity of the particular ecosystem, not just the species of concern. Although in the case of a species at risk the immediate goal is to stabilize the population, the landscape approach recognizes that by addressing the stability of the entire ecosystem, the threatened species also benefits.

Increased numbers of a particular species can upset the balance of a ecosystem, as the burgeoning population requires more food and, if individuals of the species each require substantial territory, can exceed the available space. The limit of an ecosystem on the numbers of any particular species is known as the carrying capacity. There are differing carrying capacities for different species.

Carrying capacity is determined by whatever factor limits the particular population. For wolves, the limiting factor can be territorial size, while for deer the limiting factor can be the available food.

A wildlife population management strategy that can be very effective is hunting. A well-known example is the hunting of deer that takes place in the autumn. Hunters must possess a current license. The number of licenses issued in any year is governed by estimates of the deer population in the state. In years when the deer population is high, more licenses will be issued.

The predator-prey balance is an important influence on wildlife populations. In the absence of wolves, for example, the number of deer can rapidly increase. The high number can exceed the carrying capacity of its habitat, leading to a die-off and the sudden decline in the population.

There are various approaches to managing wildlife. One approach involves the restoration of habitats that have been damaged. One example is the restoration of a wetland. Controlled hunting such as annual deer hunts is another example. A third example is the monitoring of species and the use of the estimated numbers to decide if the species is under threat. Another approach is to review development planned for a region to determine if it could damage vulnerable land or disrupt migratory routes, as two examples, and, if so, to modify or cancel the development.

Impacts and Issues

Wildlife population management is a human-mediated endeavor that involves the work of wildlife biologists, politicians, and volunteers. As well, natural and climatic factors operate. The efforts of non-profit organizations such as Ducks Unlimited, Nature Conservancy, and the Sierra Club have and continue to be tremendously helpful in preserving a variety of bird and animal species.

WORDS TO KNOW

CULL: The selection, often for destruction, of a part of an animal population.

ECOSYSTEM: The community of individuals and the physical components of the environment in a certain area.

POACHING: Illegal hunting.

The near extinction of the bison and the extinction of the passenger pigeon attests to the destructive influence that humans can have in the absence of protective legislation. The implementation and enforcement of wildlife protective laws continues to be an important aspect of population management, especially in areas of the world where poaching is decimating populations such as the tiger and rhinoceros. But, the increased numbers of bison and the rescue of the Whooping Crane from the brink of extinction also attests to the success of population management campaigns.