Making structured decisions for reintroduced populations in the face of uncertainty

Abstract

Structured decision-making (SDM) has become popular in natural resource management but has been underused in reintroduction programs. We illustrate how conservation managers can use SDM to guide management decisions after initial reintroduction, when data are still limited and uncertainty around vital rates estimates is high. In 2013, the hihi (Notiomystis cincta), an endangered New Zealand forest bird, was reintroduced to Bushy Park (BP), a managed conservation reserve. High post-release mortality in females led to the population remaining small after 2 years, raising the question of whether more females should be released. We built a model to evaluate three management alternatives, including no further translocation and translocations of 15 additional females (from the only possible source population) in either 2015 or 2016. The fundamental objectives identified were to maximize the number and persistence of female hihi in BP, minimize the impact on the source population, and minimize costs. Our decision analysis incorporated uncertainties in parameter estimation, model selection, and demographic stochasticity. It produced distributions of final scores for each management alternative based on population projections for both the BP population and source population, and objective weights assigned by stakeholders. Although the distributions of final scores overlapped greatly, the "no translocation" alternative was largely stochastically dominant over other management options, that is, it was clearly the best choice in most projections and the choice was ambiguous in the remaining projections. The decision was also unaffected by variation in stakeholder values. Although the underlying modeling was complex, the output provided a simple visualization of outcomes that allowed the recovery group to make an informed decision (no further translocation) that fully considered the uncertainties. K E Y W O R D S

Preparing for translocations of a Critically Endangered petrel through targeted monitoring of nest survival and breeding biology

“…Firstly, by applying a novel Bayesian multi-stage nest survival model, we provide insights into nest survival. Estimates of demographic parameters such as nest survival are of vital importance when making structured decisions on conservation management (including translocations) in the face of uncertainty (Panfylova et al, 2019). For wide-ranging species such as petrels, nest survival, not juvenile or adult survival, will be the likely driver of translocation success, making nest survival estimates crucial for projecting future population trajectories at translocation sites.…”

Prioritizing among removal scenarios for the reintroduction of endangered species: insights from bearded vulture simulation modeling

“…Our simulation approach provides a vital tool for planning the management and conservation of a threatened long-lived population and for making objective decisions regarding trade-offs in future reintroduction projects (Converse et al, 2013;Lloyd et al, 2019;Panfylova, Ewen & Armstrong, 2019). Quantitative modeling provides explicit predictions about future population trends and the uncertainty surrounding forecast population trajectories under different extraction regimes and allows the pros and cons of different removal alternatives to be assessed.…”

“…The search for innovative and effective methods to improve and optimize species conservation programs is a key issue for managers, conservationists and policy-makers responding to biodiversity loss. The translocation of individuals to formerly occupied habitats is a widespread and increasingly used tool in conservation programs to restore wild populations of endangered species (Seddon, Armstrong & Maloney, 2007;P erez et al, 2012;Seddon et al, 2014;Brichieri-Colombi & Moehrenschlager, 2016;Swan, Lloyd & Moehrenschlager, 2018). Because the economic and time costs of population replenishment and reintroduction projects can be limiting factors (Smith et al, 2011), reliable assessments of the effectiveness of various management options are essential in choosing the best course of action (McCarthy, Armstrong & Runge, 2012).…”

Co‐development of a risk assessment strategy for managed relocation

“…Others have analysed some components of risk (e.g. fiscal risk, risk to the target, overall uncertainty) within decision frameworks (Canessa, 2015; Panfylova et al., 2019; Rout et al., 2013). However, in looking at managed relocation from a Federal decision process perspective, we concluded that there are times and places where a broader spectrum of risk needs to be assessed.…”