Details

Autor(en) / Beteiligte

• Lloyd, N. A.
• Hostetter, N. J.
• Jackson, C. L.
• Converse, S. J.
• Moehrenschlager, A.

Titel

Optimizing release strategies: a stepping‐stone approach to reintroduction

Ist Teil von

• Animal conservation, 2019-04, Vol.22 (2), p.105-115

Ort / Verlag

London: Wiley Subscription Services, Inc

Erscheinungsjahr

2019

Quelle

Wiley Online Library Journals Frontfile Complete

Beschreibungen/Notizen

• Evaluation of alternative management strategies enables informed decisions to accelerate species recovery. For reintroductions, post‐release survival to reproductive age is a key parameter influencing population growth. Here, we trial a ‘stepping‐stone’ method to maximize the success of captive‐bred animals when the availability of more suitable wild‐born release candidates is limited. Our approach makes use of relatively safe and established wild populations to prepare captive‐bred individuals for eventual translocation to a final release destination, thus building resilience through establishment of multiple populations over time. We developed a novel multievent model integrating encounter history and biotelemetry data to evaluate reintroduction strategies for the critically endangered Vancouver Island marmot Marmota vancouverensis. We compared post‐release survival of 176 individuals (52 wild‐born, 47 captive‐bred marmots released directly to destinations, and 77 captive‐bred marmots released with a stepping‐stone approach). Survival estimates to prime breeding‐age (PBA), were then used to quantify expected success of potential release strategies. Our analysis indicates that post‐release survival varies by source population and release method, as well as age, season, year, and years since release. Conditional on an objective of maximizing survival to PBA, our results suggest that using wild‐born marmots for translocations as often as possible, and stepping‐stone captive‐bred marmots prior to final release, will result in the best outcomes. There was a 0.86 probability that survival to PBA was greater for captive‐bred marmots released as yearlings using a stepping‐stone approach (survival to PBA mode = 0.13, 95% CRI = 0.05–0.30) than for captive‐bred animals that were directly released to destination sites as one‐year‐olds (survival to PBA mode = 0.04, 95% CRI = 0.01–0.24). Consequently, the stepping‐stone approach yields much higher population establishment or growth potential than previous release strategies that used captive‐bred marmots. Optimizing the combination of release candidates, sites and timing can thereby increase the effectiveness of reintroductions. Evaluation of alternative management strategies enables informed decisions to accelerate species recovery. For reintroductions, post‐release survival to reproductive age influences population growth but captive‐bred animals frequently have compromised survival. Here we explore a novel ‘stepping‐stone’ approach to improve the contribution of captive‐bred animals by optimizing release strategies across multiple sites for the critically endangered Vancouver Island marmot (Marmota vancouverensis), and by using an innovative multievent model integrating encounter history and biotelemetry data, we evaluated different reintroduction strategies. The stepping‐stone approach yielded higher population establishment or growth potential than other release strategies for captive‐bred marmots. Optimizing the combination of release candidates, sites, and timing can thereby increase the effectiveness of reintroductions. Photo credit: Stock Photo.