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5. Managing genetic and behavioural changes. When captive populations are established for conservation and recovery purposes, the preservation of extant genetic variation and species typical behaviour assumes paramount importance. Over the past decade, considerable attention has been given to the preservation of genetic diversity in small populations. Modern, conservation-oriented breeding programmes attempt to ameliorate the genetic effects of inbreeding, drift, and adaptation to the captive environment through the deliberate and careful control of reproduction, population size, and population demography (Foose and Ballou 1988, Lacy 1987, Allendorf 1993). This is a challenging task, however, given:
a) the practical limitations in controlling population size and reproduction,b) the dynamic nature of evolutionary forces in small populations,c) the types of genetic variation to be maintained, and,d) the uncertain nature of selection in the captive environment (see Lande 1988 Simberloff 1988). In low-fecundity taxa, like most parrots, careful preparation of stud books and pedigree breeding to equalise progeny number in family lines can minimize genetic drift and adaptation to captivity (Allendorf 1993). However, it must be recognised that breeding programmes for endangered parrots have often failed to secure consistent reproduction and have been unable to equalise progeny numbers in family lines or pursue any other consistent genetic strategies, even after years of effort. Further, some stocks in captivity have been genetically debased by ill-advised cross-breeding with other races and do not constitute acceptable stocks for release on genetic grounds (see Triggs and Dau gherty 1996).
Much less attention has been given to the preservation of species-typical behavioural traits. Behavioural traits, especially those that are learned or culturally transmitted, are prone to rapid loss in captivity. The behavioural repertoires of many parrot species include many learned components, and problems with behavioural deficiencies have already been encountered in attempts to re-introduce captivebred individuals of several species to the wild (see Wiley et al. 1992, Snyder et al. 1994). Because the cultural transmission of information across generations appears to be essential for the survival of wild populations of some highly social species such as parrots (Toft 1994), breeding programmes for re-introduction must focus careful attention on behavioural management in the captive environment. Clearly, this aspect of captive management deserves much more scientific investigation than it has received, and will have to be undertaken on a species-by-species basis.
6. Problems in ensuring continuity of programmes. Captive breeding represents a relatively unstable and inputintensive approach to conservation that is difficult to sustain over the several decades often needed for the recovery of endangered species. Changes in personnel, institutional priorities, and financial resources can frequently leave long-term programmes without adequate support and expertise. The Puerto Rican parrot captive programme, for example, has suffered several periods of substantial difficulty in maintaining optimal efficiency over the more than 25 years of its existence. Of course, problems with continuity are not unique to captive breeding programmes, and can affect complex in situ conservation efforts as well.
7. Pre-emption of other, better techniques. Captive breeding can sometimes pre-empt attention and resources from better, long-term conservation solutions. The existence of a captive population can give the impression that the species is safe and allow agencies to ignore long-term solutions that are often more difficult politically, though much more effective and beneficial biologically (see discussion and examples in Snyder et al. 1996). Because of the risks and limitations of captive breeding, it should be invoked as a species recovery approach only under carefully defined circumstances. The decision to start captive breeding for this purpose should be made only on a case-by-case basis and only following a comprehensive evaluation of conservation alternatives at the field level. It should not be made simply because some individuals are already in captivity and numbers of the species seem relatively low. Further, it should not be made when resources to conduct captive bree ding comprehensively and humanely are unavailable.
In general, captive breeding can be justified as a desirable recovery approach when: (1) species are so rapidly approaching extinction that they cannot be expected to survive without intensive intervention of some sort and either effective conservation alternatives are clearly unavailable in the short term or sufficient time to investigate alternatives does not exist; or (2) all or nearly all individuals of a species are already in captivity and it is deemed worthwhile to attempt re-establishment of wild populations; or (3) other conditions prevail that make captive breeding and re-introduction absolutely essential for preservation of the species in the wild.
When captive breeding should begin for species in decline is often a point of vigorous controversy. Clearly, waiting too long before starting will risk genetic deterioration and potential failure in developing adequate husbandry techniques, especially if technology for captive breeding of the species or closely related species has not previously been researched. However, starting too soon can represent unnecessary expense, can accentuate genetic and behavioural management problems, and can focus resources in non-crucial directions, pre-empting other approaches that can offer potentials for more stable, longterm benefits.
Population trends are often far more important than absolute numbers in making decisions as to whether and when captive breeding is warranted. Steeply declining species are cause for special concern, and care needs to be taken not to wait too long in establishing captive populations if effective alternatives are unavailable. In making such decisions it is crucial to recognise the difference between ephemeral short-term population fluctuations and pervasive long-term population trends. Well constituted recovery teams weighing the many factors that need to be considered are probably the best mechanism for determining whether and when captive breeding is needed for a particular species. The decision should not be delegated to parties, such as private captive breeders, who have a personal stake in the captive breeding.
Captive-breeding programmes for species recovery should not be established independent of efforts to develop alternative, long-term conservation solutions for wild populations. In general, wild populations should be sustained at the time captive populations are established so that research into limiting factors can take place and problems in the wild can be identified and corrected. Also, existing wild populations can present a valuable link for re-introduced individuals.
Finally, captive breeding efforts for species recovery should proceed only when endorsed by the governments of the countries involved. Although extranationals may beuseful in helping launch such programmes and in providing training, programmes should primarily involve participation by local conservationists. It is crucial that birds involved in captive breeding efforts be under the control of integrated conservation programmes so that disputes as to ownership of birds and as to the management and fate of birds do not disrupt progress toward conservation goals. Captive and wild populations of a species must be managed as one interactive entity under control of a single conservation authority.
Reproduced with permission of the International Union for Conservation of Nature and Natural Resources and the World Parrot Trust.
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