click here for Chapter 15 detailed table of contents
Minimum population size, home range, and fluctuations in wild populations
The success of conservation and wildlife management programs often hinge on a detailed understanding of the habitat requirements of species in the wild:
Another critical concern is the effect of habitat fragmentation on population viability. Fragmentation of large populations into smaller units may disrupt mating systems, leading to inbreeding and loss of genetic diversity. Animal behaviorists play a critical role in assessing home range size and mating system, and dispersal patterns. This information is then used to determine the effective size of the population, and to make recommendations concerning the reserve size needed to conserve the species.
Understanding how behavior changes in naturally fluctuating populations also helps animal behaviorists to predict the effects of habitat change or captivity on animals.
Welfare and breeding in captive populations
Scientific knowledge of animal behavior has been applied in the related areas of animal welfare and breeding in captive populations. Captive populations include both representatives of wild animals in zoos and domestic animals maintained in agricultural settings. Often captive animals exhibit behavioral pathologies, such as cribbing (chewing cage or stall bars) and repetitive pacing. Studies by behaviorists have shown how modifications of captive environments, generally by making them more complex and therefore "interesting" to the animals causes them to stop displaying behavioral pathologies.
Some animal species do not successfully breed in captivity, either because they fail to mate or because they fail to care of their young. This is a critically important problem when captive populations of rare or endangered species are being maintained with the ojbect of reintroducing animals to the wild. Careful studies by animal behaviorists often lead to succcessful techniques to encourage mating and parenting in captive situations.
Wild animals in urban and suburban settings--conservation and management issues
Many animals are able to coexist with humans in urban environments. Some species even do much better than in their native habitats. Urban animals range from species regarded as out-and-out pests, like Norway rats, to animals with which we coexist easily, such a squirrels. There is quite an array of species with which the relationship is more uneasy--animals that are welcomed by some people, or some of the time, but which other people, or at other times, are viewed as problematic in urban settings. Each species presents its own issues. As a general rule, animals must habituate to the presence of humans and their companion animals to function in urban and suburban habitats; this is probably the biggest barrier to establishment in urban areas for wild animals. Hunger can lower the threshold for habituation, so in years in which natural food supplies fail, surprising species, or surprising numbers of animals, may enter suburban and urban habitats in search of food.
Changing human cultural perceptions concerning hunting and killing "pest" animals also plays a key role in the interactions between humans and animals in surburban/urban habitats. Even when the public demands removal of potentially dangerous animals, such as mountain lions and bears, there is often intense accompanying pressure to relocate an animal, rather than kill it. Relocation sometimes works, but often there is a level of futility in returning an animal to a habitat which is depleted of food or where all potential territories are occupied. In addition to relocation and killing, control measures generally involve discouraging wildlife from particular locations.
Many urban animals are not native to the surrounding landscape. This includes feral (escaped to the wild) cats, Norway rats, pigeons, English sparrows and starlings. Eastern fox squirrels and raccoons originally did not occur in the Western U.S., but are now well established in some Western cities. Some biologists have argued that the ethics of removal and possible killing of these species is different, because of their status as introduced species, while others have argued that the same wildife values apply to all species, whether native or not.
The role of behavior in reintroduction programs
In extreme cases, a species approaches extinction in the wild and governmental authorities decide to breed the species in captivity, with the goal of supplementing existing populations with captive-bred animals or of creating new populations where wild populations have gone extinct. Wildlife managers may also attempt to create new populations by translocating animals from other wild populations. Behavioral studies are extremely important in guiding these programs to success. Development of appropriate foraging strategies, social interactions, mating behavior, and parental care may all be disrupted by life in captivity. Animal behaviorists attempt to prevent these problems and act to insure normal behavioral development; these activities play a key role in reintroduction programs.
The following examples illustrate how animal behaviorists have worked in reintroduction programs:
Return to Table of Contents
copyright ©2001 Michael D. Breed, all rights reserved