Decision analysis for the planning and assessment of ex situ management: An application to the endangered mahogany glider

• Published in: Austral ecology 2023-06, Vol.48 (4), p.803-821
• Main Authors: Rout, Tracy M., Jackson, Stephen M., Adam, Dalene, Diggins, Jacqui, McDonald‐Madden, Eve, Mitchell, Nicola J., Walshe, Terry V.
• Format: Article
• Language: English
• Subjects: Botanical gardens; Captive breeding; Cost benefit analysis; Decision analysis; Decision making; decision tool; decision tree; event tree; expert elicitation; Management; Seed banks; Seeds; structured decision‐making; Swietenia; value judgements
• ISSN: 1442-9985; 1442-9993
• DOI: 10.1111/aec.13310

Ex situ (‘off‐site’) management refers to keeping species in artificial conditions away from their natural habitat and includes captive breeding facilities, botanical gardens and seed banks. There is scope for ex situ programmes to be more commonly used for supplementing or establishing wild populations. However, undertaking ex situ management comes with risks, costs and uncertainties, which must be assessed in the context of available in situ (‘on‐site’) management options. The PACES (Planning and Assessment for Conservation through Ex situ management) tool tailors the principles of structured decision‐making to the specific problem of assessing and comparing ex situ and in situ management options. We applied the PACES tool to the mahogany glider (Petaurus gracilis), a threatened arboreal marsupial endemic to north Queensland, Australia. Through an expert elicitation process, we predicted the likely benefits of an ex situ and two in situ management options, as compared to a baseline ‘do‐nothing’ scenario. The ‘in situ plus’ alternative (where extra resources are dedicated to in situ management) was predicted to result in the largest population increase according to the participants' best estimates. However, this benefit came at a much larger cost than the ex situ alternative, and without the benefit of an ex situ insurance population. The PACES tool assessment allowed the Mahogany Glider Recovery Team to document and plan the financial costs, risks and benefits of potential future management options for the mahogany glider, laying a transparent basis for future assessment and decision‐making. The PACES (Planning and Assessment for Conservation through Ex‐Situ management) decision tool allows conservation managers to weigh the risks and benefits of ex situ management, as recommended by the IUCN guidelines. It uses a practical approach built on best‐practice decision science, ensuring decisions can be transparent and informed by the best available information. This study is the first to describe the PACES tool and its application to the endangered mahogany glider in north Queensland, Australia.