Genetic and demographic modeling for animal colony and population management

Abstract

In captive breeding populations as well as laboratory research colonies, computer modeling has proven to be an extremely valuable tool for management purposes: defining population size objectives, estimating required rates of harvest or reproduction, and identifying genetically important individuals. The techniques described in this paper are now routinely used in most captice breeding programs, partially because computer software has been developed and data bases standardize to facilitate their application but also partially because of the increasing need for prudent management of limited resources. The application of computer modeling has not been as extensive in laboratory research colonies. However, careful management based on modeling and analyses of population trends can help make maximum use of the animals and facilities available. For example, by basing breeding programs on mean kinship we are targeting the genetically most important individuals in the population. The end result is that colonies and populations are more efficient in meeting their objectives. For laboratory research colonies, this may mean more efficient and improved reproductive output at lower costs. For captive breeding programs this means we can afford to breed fewer individuals and maintain smaller overall population sizes to achieve the same objectives in terms of genetic diversity. The benefits are clear: smaller more carefully managed populations use fewer resources leaving more for other species also in need of captive breeding. The alternative, relaxing or ignoring genetic and demographic management, has clear economic and conservation costs: larger populations are required and thus fewer populations can be maintained under fixed resources. Additionally, unmanaged populations may either grow out of control or decline to extinction due to lack of monitoring. Failing to monitor inbreeding will lead to poorer health and higher mortality of inbred animals, which also incurs a cost in itself. While endangered species captive breeding programs and research laboratory colonies differ significantly in their primary goals, both share the need for judicious management of animal resources. Computer modeling can help both the genetic and demographic management of these populations and thereby reduce resource expenditures.