Using expert knowledge to support Endangered Species Act decision‐making for data‐deficient species

Abstract

Many questions relevant to conservation decision-making are characterized by extreme uncertainty due to lack of empirical data and complexity of the underlying ecologic processes, leading to a rapid increase in the use of structured protocols to elicit expert knowledge. Published ecologic applications often employ a modified Delphi method, where experts provide judgments anonymously and mathematical aggregation techniques are used to combine judgments. The Sheffield elicitation framework (SHELF) differs in its behavioral approach to synthesizing individual judgments into a fully specified probability distribution for an unknown quantity. We used the SHELF protocol remotely to assess extinction risk of three subterranean aquatic species that are being considered for listing under the U.S. Endangered Species Act. We provided experts an empirical threat assessment for each known locality over a video conference and recorded judgments on the probability of population persistence over four generations with online submission forms and R-shiny apps available through the SHELF package. Despite large uncertainty for all populations, there were key differences between species' risk of extirpation based on spatial variation in dominant threats, local land use and management practices, and species' microhabitat. The resulting probability distributions provided decision makers with a full picture of uncertainty that was consistent with the probabilistic nature of risk assessments. Discussion among experts during SHELF's behavioral aggregation stage clearly documented dominant threats (e.g., development, timber harvest, animal agriculture, and cave visitation) and their interactions with local cave geology and species' habitat. Our virtual implementation of the SHELF protocol demonstrated the flexibility of the approach for conservation applications operating on budgets and time lines that can limit in-person meetings of geographically dispersed experts.

Climate tipping points and expert judgment

“…While there is not a standard definition of structured elicitation protocols agreed upon by the entire community, these protocols generally refer to a formalized methodology combining various steps to obtain the judgments of a group of experts, which are then aggregated with the goal of answering a question or set of questions about the domain or system (Hanea et al, 2021). These protocols have taken many forms, like the Delphi Method (Dalkey, 1969), Cooke's Model (Cooke, 1991), and the SHELF Protocol (Oakley & O'Hagan, 2016), 7 which have been used across a range of scientific disciplines, from determining training priorities for medical students (Viljoen et al, 2020) to assess extinction risk of subterranean aquatic species (Fitzgerald et al, 2021). What should be noted is that all of these methods utilize some form of a structured elicitation protocol for the formalization of expert judgments.…”

Transforming Conservation

“…Two other notable protocols for eliciting expert judgements that are also applied in ecology include the Sheffield Elicitation Framework (SHELF) (Gosling, 2018), which is also akin to the Delphi technique but which relies on behavioural aggregation (Fitzgerald et al, 2021;O'Hagan, 2019), and the Classical Model (also known as Cooke's Method), which typically only allows a single estimate from experts and uses performance-weighted aggregation (Cooke, 1991). Recent applications of the IDEA protocol have adopted the performance-weighted aggregations of the Classical Model, that is, giving greater weight to the judgements of those who performed better on test questions (Barons and Aspinall, 2020;Hanea et al, 2021a).…”

An expert-based global assessment of threats and conservation measures for subterranean ecosystems

“…As global monitoring programs and unbiased data are poorly available, we must explore alternative approaches to advance our knowledge on subterranean ecosystems. In the case of other data-poor scenarios, expert opinion emerged as a valuable tool for consolidating a first understanding on current threats and conservation needs (Branco & Cardoso, 2020; Chamberlain et al, 2016; Fitzgerald et al, 2021; Luo et al, 2023; Miličić et al, 2021; O’Neill et al, 2008). Indeed, when lacking hard data, expert opinion plays a fundamental role in conservation (Martin et al, 2012), e.g.…”