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Responses from an expert elicitation of lynx viability and persistence in the continental United States

Citation

Cummings, Jonathan (2020), Responses from an expert elicitation of lynx viability and persistence in the continental United States, Dryad, Dataset, https://doi.org/10.5061/dryad.0rxwdbrxg

Abstract

The data and code provided here is associated with an October 13-15 Lnyx expert elicitation workshop that assessed the viability and persistence of lynx in the continental United States. The expert elicitation captured the knowledge, professional judgments, and opinions of lynx experts to assess the status of, and the drivers influencing, these lynx populations. We elicited the likelihood and level of uncertainty regarding future persistence over several time frames (at years 2025, 2050, and 2100). This data was used to inform the species status assessment and providing scientific information to the United States Fish and Wildlife Service used to complete the November 2017 5-year Endangered Species Act status review which recommended that the lynx DPS be removed from the list of threatened and endangered species.

Methods

Study Species

This data and R code pertains to the Canada lynx (Lynx canadensis) in the contiguous (Lower 48) United States. Lynx in this geographic area are members of a distinct population segment (DPS) designated by the United States Fish and Wildlfe Service. Data was collected for six geographic areas suspected to support resident lynx populations in the DPS:  northern Maine (with occasional/sporadic breeding by small numbers of lynx in northernmost New Hampshire and Vermont); northeastern Minnesota; northwestern Montana and northeastern Idaho; north-central Washington; western Colorado and the Greater Yellowstone Area of southwestern Montana and northwestern Wyoming. While several other areas peripheral or proximal to the 6 geographic units described above are known or suspected to have supported small numbers of resident lynx historically, either intermittently or as small but persistent resident populations, due to their small numbers and higher uncertainty in current status we did not elicit persistence specifically for these peripheral lynx.

Identifying Experts

Lynx SSA Team members reviewed the relevant literature and used their first-hand knowledge to identify experts involved in lynx and hare research or management, boreal forest ecology, and climate modeling. Selection criteria helped ensure that invitations to participate were made only to scientists with expertise highly relevant to projecting future conditions for lynx and, further, that the selections were transparent, unbiased, and adequately captured the diversity of expertise and professional judgments related to the topics. Selection was not based on participants’ affiliations; however, States and other partners were asked to review the draft list of workshop invitees and suggest alternate or additional qualified experts that meet the selection criteria. Using the criteria, candidates for the lynx expert panel were contacted to determine their interest and ability to attend the workshop. While not an explicit item in the selection criteria experts were also drawn from each geographic unit and the expert panel included experts conducting studies across multiple units and Canada, the more intact and abundant portion of lynx’ North American range. Among the experts both initially interested in and able to attend the workshop, the team extended invitations to 13 candidates, 10 of whom ultimately were able to attend and participated as panelists. 

Elicitation Format

In accordance with the expert elicitation literature (e.g., Burgman 2005, USEPA 2011, Gregory et al. 2012, Drescher et al. 2013, Morgan 2014), the facilitators developed expert qualification standards for expert selection and a used a Delphi based approach to elicit opinions from the expert panel for each question, as described below. All estimates were provided in a 3-day workshop, one and a half days of presentations followed by one and a half days of elicitation, held in Bloomington, Minnesota from October 13-15, 2015. When estimates were combined, they were mathematically aggregated by taking the median.

Questions

We asked the expert panelists to supply input on three categories of lynx condition:  representation, redundancy, and resiliency. These categories are used in all SSA processes. At the time of this SSA these definitions had not been standardized across SSA’s and were therefore defined for panelists. Before questions in each category were asked, we visually displayed and read the definition of each category to the panelists and allowed them to ask any questions they had about the definition. After definitions were provided and panelists were ready to proceed, we worked through the questions for that category, using the methodology described in the elicitation process section below.

The questions asked of the expert panelists, by category, in their revised form as applicable, and the response type requested.

Category

Question

Response Type

Representation

1.1:  Are any of the geographic units susceptible to genetic drift on a scale that would limit genetic viability? If yes, which geographic units?

“Yes” accompanied by a list of susceptible geographic units, or “No”.

1.2:  Are there locations from a lynx perspective that have unique habitat conditions relative to other areas in the lynx range that are necessary to foster future adaptive capacity of the DPS? If yes, where?

“Yes” accompanied by a list of susceptible geographic units, or “No”.

Redundancy

2.1:  List the factors/catastrophic events that could functionally extirpate an entire geographic unit.

A list of events, or “None”.

2.2:  Could any of the catastrophic events listed in response to redundancy question 1 eliminate all 6 geographic units simultaneously?

“Yes” accompanied by a list of events, or “No”.

2.3:  What is the probability (expressed as a percentage) that any single geographic unit could be eliminated by a single catastrophic event in the next 10 years?

1-point elicitation:  0-100%.

2.4:  What is the percent likelihood that a series of catastrophic events within the next 10 years could cause functional extirpation of one or more lynx geographic units?

1-point elicitation:  0-100%.

2.5:  What length of time would be required for a geographic unit eliminated by a catastrophic event to reestablish naturally?

4-point elicitation:  shortest, longest, most plausible, and confidence (0-100%) in range.

Resiliency

3.1:  What is the probability of persistence over time (particularly at present, 2025, 2050, and 2100) by geographic unit?

Graphical 3-point elicitation:  graphically plot the lowest, highest, and most likely probability of persistence out to 2100 adding points for 2015 (present), 2025, 2050, and 2100.

 

3.2:  What are the major drivers/factors (up to 3) reducing probability of persistence for each of the major geographic units?

Ranked list of top three factors at each time period (2025, 2050, 2100)

 

3.3:  What conservation actions could be taken that would address the factors impacting the probability of persistence, or would otherwise increase the probability of persistence?

Response Type:  Round robin list creation. Facilitators cycled through experts asking for a single previously unstated action until each expert had no further actions to provide.

Elicitation Process

Although invited experts were expected to contribute openly and effectively to group discussions, we did not seek consensus among experts; rather, we probed differences of opinion or interpretation of scientific and technical information. We also asked experts and others present at the workshop to focus on scientific questions and to refrain from discussing or recommending management or policy decisions related to the Service’s authorities and responsibilities in implementing the ESA unless directly requested. Only responses from members of the expert panel were recorded. However, panelists were provided the opportunity to confer with the subject matter specialists and SSA Team members in attendance as needed prior to providing an official response for the record.

In questioning, we used a modified Delphi method (e.g., MacMillan and Marshall 2006). We first elicited individual responses/scores to a question with experts submitting their scores independently via submission sheets with anonymous ID numbers. Following the initial response, the anonymous responses were displayed, and facilitators noted where there was high congruence among responses, as well as low congruence or outlying responses and then asked for voluntary expression of potential rationale supporting the median, endpoint, and other divergent responses. Anonymity was encouraged during this process, i.e., panelists need not have stated which response was theirs or provide rationale related to their response, however panelists chose at times to voluntarily state which response was theirs. Following discussion panelists were given time to reconsider their response and provide their final response which was recorded for the record. Where aggregation of responses occurred, we report the median response.

In addition to elicited responses to each question, we often received feedback from the experts on definitional issues and the wording of the questions themselves; based on which the elicitation facilitators and Lynx SSA Team revised the questions as needed. In the case of a revised question, the process was repeated starting with the revised question. That is, scores were elicited and displayed for the revised question, an additional opportunity for rationale, comment, and discussion was provided, which was followed by a third and final response submission.

The Lynx SSA Team and Elicitation Facilitators scripted questions for experts prior to the meeting. Because of the uncertainty related to the status of lynx populations in each of the geographic units and factors influencing lynx biology, questions were phrased in a manner to obtain quantifiable or discrete responses. The types of questions and the format of responses differed based on the information needed to inform the status assessment, as well as the best way to capture information relevant to the question being asked. For example, responses were requested in the form of lists when a set of influences was desired, and in the form of a 4 point elicitation (Speirs-Bridge et al. 2010) – e.g., the high and low end values of a range, confidence that the range contains the true value, and the most likely value  – when an uncertain quantitative value was desired, or in the form of graphed trajectories when probabilities of persistence over time were desired, and other forms as necessary. Based on prior discussions within the Lynx SSA Team that determined the range of uncertainty from questions 2.5 and 3.1 regarding reestablishment time and probability of persistence would be most consequential to the SSA and listing process, as well as the limited time available for elicitation, a single point elicitation was used for questions 2.3 and 2.4 regarding catastrophic events rather than the 4-point and 3-point elicitation graphic responses used in questions 2.5 and 3.1 respectively.

All panel members were encouraged to respond to each question but also given the option of abstaining if they felt it was beyond the bounds of their expertise. With few exceptions, all 10 expert panelists responded, and as requested. In a few cases, as noted in the results, due to an expert’s desire to provide more detail, or to limit follow-up with an expert due to the time available for elicitation, responses differed from the requested response type.

In the case of questions 3.1 and 3.2 regarding probability of persistence and the factors driving persistence probability, we used a custom elicitation technique. We asked these questions concurrently as part of a probability-of-persistence exercise conducted for each geographic unit. We asked experts to graphically provide the probability of persistence – i.e., the probability that resident lynx would not be functionally extirpated – of resident lynx through time for each geographic unit, as well as the major factors influencing persistence in those geographic units, one geographic unit at a time. Experts were asked to provide persistence probabilities and influencing factors for the near-term (2025), mid-term (2050) and longer-term (2100). Unlike question 2.5, and as noted can be preferable by Hemming et al. (2018a), experts chose to present the full range of outcomes through a 3-point elicitation; i.e., providing their “most likely” persistence probabilities as well as “low” (worse case) and “high” (best case) persistence probability values to express the full range (100%) of their uncertainty at each future time frame (e.g., Hanea et al. 2018).

Prior to expert resiliency (probability of persistence) responses for questions 3.1 and 3.2, the expert(s) most familiar with the geographic unit in question restated their presentations from earlier in the workshop as a 5 to 10-minute summary of covering what they viewed as the most relevant information about the current and likely future status of lynx populations and habitats in that unit  They also presented any other conditions or issues they thought could affect (either positively or negatively) the probability of persistence of resident lynx in that unit. All experts then completed their graphs and lists of the factors that influenced the probabilities of persistence they selected for each time frame for the geographic unit in question. After all experts completed their responses, the graphs and influence lists from each expert for a given geographic unit were visually displayed and workshop participants were invited to gather around to view and participate in a facilitated discussion regarding what drove the responses for that unit. These questions were a mix of directed questions about unique responses, the role of factors noted in the responses, and open-ended questions to allow experts to describe their thinking. Experts and team members were also encouraged to ask clarifying questions about the responses. For each geographic unit, experts were given an opportunity to post revised responses following these discussions.

Usage Notes

Files provided

File Name Description
Lynx Supplement.Rmd The is the R code used to analyze the elicitation responses
Redundancy Responses part1.csv This csv file contains the experts responses to elicitiation questions three and four regarding redundancy.
Redundancy Responses part2.csv This csv file contains the experts responses to elicitiation question five regarding redundancy.
Resiliency Responses.csv This csv file contains the experts responses to elicitiation questions regarding resiliency.