Ark or park: the need to predict relative effectiveness of ex situ and in situ conservation before attempting captive breeding

Abstract

Summary1. When species face extinction, captive breeding may be appropriate. However, captive breeding may be unsuccessful, while reducing motivation and resources for in situ conservation and impacting wild source populations. Despite such risks, decisions are generally taken without rigorous evaluation. We develop an individual-based, stochastic population model to evaluate the potential effectiveness of captive-breeding and release programmes, illustrated by the critically endangered Ardeotis nigriceps Vigors great Indian bustard. 2. The model was parameterized from a comprehensive review of captive breeding and wild demography of large bustards. To handle uncertainty in the standards of captive-breeding performance that may be achieved, we explored four scenarios of programme quality: 'full range' (parameters sampled across the observed range), 'below average', 'above average' and 'best possible' (performance observed in exemplary breeding programmes). Results are evaluated examining: (i) the probability of captive population extirpation within 50 years and (ii) numbers of adult females subsequently established in the wild following release, compared to an alternative strategy of in situ conservation without attempting captive breeding. 3. Successful implementation of captive breeding, involving permanent retention of 20 breeding females and release of surplus juveniles, required collection of many wild eggs and consistent 'best possible' performance across all aspects of the programme. Under 'full-range' and 'above-average' scenarios, captive population extirpation probabilities were 73-88% and 23-51% respectively, depending on egg collection rates. 4. Although most (73-92%) 'best possible' programmes supported releases, re-establishment of free-living adults also required effective in situ conservation. Incremental implementation of effective conservation measures over the initial 10 years resulted in more free-living adults within 35 years if eggs were left in the wild without attempting captive breeding. 5. Synthesis and applications. For the great Indian bustard Ardeotis nigriceps, rapid implementation of in situ conservation offers a better chance to avoid extinction than captive breeding. Demographic modelling of threatened species should be used to examine whether captive breeding will bring net benefits to conservation programmes.

Effects of habitat and livestock on nest productivity of the Asian houbara Chlamydotis macqueenii in Bukhara Province, Uzbekistan

“…To date, the primary conservation response to this circumstance has been to release increasingly large numbers of captive-bred individuals of both Asian and African houbara Chlamydotis undulata to re-establish or reinforce exploited populations (Chargé et al 2014;Hardouin et al 2015;Islam et al 2012). Population supplementation by releases of captive-bred stock may play an important role in houbara conservation (Combreau et al 2005), but captive breeding also incurs certain genetic, disease, temperament and domestication risks (Dolman et al 2015;Frankham 2008;Snyder et al 1996;Williams and Hoffman 2009). For houbara, selection in captivity has been reported on a range of physiological, reproductive and behavioural traits (Chargé et al 2014), but the consequences for reinforced populations Electronic supplementary material The online version of this article (doi:10.1007/s10344-016-1018-9) contains supplementary material, which is available to authorized users.…”

Catastrophic ongoing decline in Cambodia’s Bengal Florican Houbaropsis bengalensis population

“…Given the small size of Cambodia's Bengal Florican population and the situation at the sites outlined above, captive breeding has been suggested as a solution. However, we caution that demographic modelling, or at least a thorough evaluation of potential impacts on wild populations and possible outcomes of captive breeding, is a prerequisite before embarking on a long and expensive programme of ex-situ conservation for a species that has never been kept in captivity (Dolman et al 2015). Although desirable, it has not been possible to increase the size of existing BFCAs, designate additional BFCAs or purchase agricultural land and convert it to grassland (Packman et al 2013b).…”

Lessons from 30 years of population viability analysis of wildlife populations

“…PVA of the ex situ population would reveal if the breeding program was adequate to meet the short or long‐term needs for supporting the in situ population. This would include assessment not only of the viability of the population as a self‐sustaining entity, but its ability to produce also animals required for releases (Dolman, Collar, Scotland, & Burnside, ; Earnhardt et al, ), research, education, or other roles. To most effectively answer these questions, a comprehensive PVA should be conducted on the metapopulation consisting of the in situ and ex situ populations.…”