Book contents
- Frontmatter
- Contents
- Foreword
- Preface
- Acknowledgements
- 1 Biodiversity and zoo conservation biology
- 2 Protecting species and habitats
- 3 Zoos in focus – public exhibition or conservation
- 4 Keeping animals in captivity
- 5 Viable captive populations – the numbers game
- 6 Captive breeding and zoos
- 7 Returning animals to the wild
- 8 Educating the public
- 9 Turning zoos into conservation centres
- Appendix 1 Commonly used abbreviations
- Appendix 2 Scientific names of species mentioned in the text
- Appendix 3 Inbreeding
- Appendix 4 Population sizes – definitions and implications
- Appendix 5 Captive breeding and genetics – definitions
- References
- Index
- Plate section
5 - Viable captive populations – the numbers game
Published online by Cambridge University Press: 05 August 2012
- Frontmatter
- Contents
- Foreword
- Preface
- Acknowledgements
- 1 Biodiversity and zoo conservation biology
- 2 Protecting species and habitats
- 3 Zoos in focus – public exhibition or conservation
- 4 Keeping animals in captivity
- 5 Viable captive populations – the numbers game
- 6 Captive breeding and zoos
- 7 Returning animals to the wild
- 8 Educating the public
- 9 Turning zoos into conservation centres
- Appendix 1 Commonly used abbreviations
- Appendix 2 Scientific names of species mentioned in the text
- Appendix 3 Inbreeding
- Appendix 4 Population sizes – definitions and implications
- Appendix 5 Captive breeding and genetics – definitions
- References
- Index
- Plate section
Summary
‘Setting conservation thresholds at a few hundred individuals only is a subjective and non-scientific decision, not an evidence-based biological one…. Many existing conservation programs might therefore be managing inadvertently or implicitly for extinction’
(Lochran Traill)Introduction
Measuring the potential for zoos to house and breed threatened species has been a cause of concern for some time, but is as yet unresolved. However, progress has been made since the 1980s around the ‘small population paradigm’, as Caughley (1994) termed it, the study of the dynamics of small populations that have declined owing to some (deterministic) perturbation and which are more susceptible to extinction via chance (stochastic) events (Chapter 1). Past theoretical and empirical work predicts that population viability should increase with increasing initial population size both among and within species (Reed et al., 2003a). Individuals in small or fragmented populations may have fewer opportunities to locate mates because of a skewed local sex ratio and/or physical isolation from conspecifics, henceforth the Allee effect (Courchamp et al., 1999, 2008). But also low demographic rates, i.e. low annual adult survival and fecundity (Beissinger, 2000) or high annual variability in these demographic rates in response to environmental variation (Stacey & Taper, 1992), can lead to extinction of small populations.
- Type
- Chapter
- Information
- Zoo Conservation Biology , pp. 112 - 141Publisher: Cambridge University PressPrint publication year: 2011