7842

• UCREFRP Catalog Number: 7842
• Author: Knopf, F. L.
• Title: Biological Diversity in Wildlife Management.
• USFW Year: 1992.
• USFW - Doc Type: 1992.
• Copyright Material: NO

Managing Genetic Diversity in Captive Breeding
and Reintroduction Programs
Katherine Ralls and Jonathan D. Ballou
Department of Zoological Research
National Zoological Park
Smithsonian Institution
Washington, D.C.
Introduction
Captive breeding and reintroduction are the most intensive (and hence most ex-
pensive) forms of wildlife management (Conway 1986, Kleiman 1989). The need
for such intensive management is usually a sign that society has failed to adequately
restrict some human impact on a taxon, such as habitat loss and degradation, direct
or indirect mortality, or the introduction of an exotic species. Thus, a captive breeding
and reintroduction program for a taxon of conservation concern should be part of a
comprehensive conservation strategy that also addresses the problems affecting the
taxon in the wild (Ballou in press, Foose 1989, Povilitis 1990). Under these circum-
stances, such programs can make substantial contributions to the preservation of
endangered taxa. For example, captive breeding and reintroduction has enabled the
peregrine falcon (Falco peregrinus) to repopulate much of North America (Cade
1990) and Arabian oryx (Oryx leucoryx) have been successfully reintroduced in
several areas of their original range (Stanley-Price 1989).
Once the need for a captive breeding program is identified, it is advisable to initiate
the program as soon as possible. Starting the program before the wild. population
has been reduced to a mere handful of individuals increases its chances of success.
This strategy provides time to solve husbandry problems, increases the likelihood
that enough wild individuals can be removed to give the new captive population a
secure genetic and demographic foundation, and minimizes adverse effects of re-
moving individuals on the wild population.
Over the last decade, it has generally become recognized that captive populations
of threatened and endangered species should be managed to maintain the genetic
diversity present in the wild individuals from which the captive population is de-
scended (Hedrick and Miller 1992, Hedrick et al. 1986, Ralls and Ballou 1986,
Soul6 et al. 1986, Templeton 1990). The first formal cooperative breeding programs
designed to maintain genetic diversity in captive populations were the Species Sur-
vival Plans of the American Association of Zoological Parks and Aquariums (AAZPA)
(Foose and Seal 1986); similar programs now have been developed in several other
countries (Hutchins and Wiese 1991) and efforts at international coordination are
underway (Jones 1990).
Managing captive populations to maintain maximum genetic diversity counters
unwanted genetic changes in captivity due to selection (Frankham et al. 1986) and
avoids possible deleterious effects of inbreeding (Ralls et al. 1988). It also preserves
future options for both the taxon and its managers (Templeton 1990): without genetic
variation, the captive individuals or their reintroduced progeny would be unable to
adapt to future environmental changes (Frankel and Soule 1981) and various man-
Managing Genetic Diversity ? 263