A Protocol for Better Design, Application, and Communication of Population Viability Analyses

Abstract

Population viability analyses (PVAs) contribute to conservation theory, policy, and management. Most PVAs focus on single species within a given landscape and address a specific problem. This specificity often is reflected in the organization of published PVA descriptions. Many lack structure, making them difficult to understand, assess, repeat, or use for drawing generalizations across PVA studies. In an assessment comparing published PVAs and existing guidelines, we found that model selection was rarely justified; important parameters remained neglected or their implementation was described vaguely; limited details were given on parameter ranges, sensitivity analysis, and scenarios; and results were often reported too inconsistently to enable repeatability and comparability. Although many guidelines exist on how to design and implement reliable PVAs and standards exist for documenting and communicating ecological models in general, there is a lack of organized guidelines for designing, applying, and communicating PVAs that account for their diversity of structures and contents. To fill this gap, we integrated published guidelines and recommendations for PVA design and application, protocols for documenting ecological models in general and individual-based models in particular, and our collective experience in developing, applying, and reviewing PVAs. We devised a comprehensive protocol for the design, application, and communication of PVAs (DAC-PVA), which has 3 primary elements. The first defines what a useful PVA is; the second element provides a workflow for the design and application of a useful PVA and highlights important aspects that need to be considered during these processes; and the third element focuses on communication of PVAs to ensure clarity, comprehensiveness, repeatability, and comparability. Thereby, DAC-PVA should strengthen the credibility and relevance of PVAs for policy and management, and improve the capacity to generalize PVA findings across studies.

Repeatability and Reproducibility of Population Viability Analysis (PVA) and the Implications for Threatened Species Management

“…The importance of communicating all inputs and outputs of PVA models in a systematic manner to ensure that studies can be repeated was recently highlighted by Pe'er et al (2013). Here we provide an empirical demonstration of the consequences should these model parameters not be reported.…”

“…While the underlying data quality (robustness) is fundamentally important in supporting conservation triage decision making, an often overlooked aspect relates to how reliable or repeatable the PVAs are themselves. This has recently been emphasized by Pe'er et al (2013) when advocating for a standard protocol for PVA that included detailed communication criteria.…”

Extinction Risk and Conservation Options for Maui Parrotbill, an Endangered Hawaiian Honeycreeper

“…Viability measures most commonly presented in PVA studies include extinction probability, population size, and estimates of time to extinction. However, it is important to evaluate the full suite of quantitative measures that PVAs produce to evaluate population viability across all models rather than relying solely on these most common measures (Pe'er et al 2013). Consequently, for each model we present mean finite rate of growth (k), probability of quasi-extinction (N , 10; PE), median population size from all iterations (N-all), and median population size from extant populations (N !…”

Population viability analyses in New Zealand: a review

“…It is critical that these methods are clearly and fully stated so that the processes represented in a particular model can be understood and the outcomes adequately contextualised (Reed et al 2002;Naujokaitis-Lewis et al 2009;Pe'er et al 2013). Worryingly not all of the methods used to develop the PVAs were always reported.…”