Using expert-elicitation to deliver biodiversity monitoring priorities on a Mediterranean island

Table 1. Results of ranking exercise of biodiversity monitoring needs. � Theme Step 2 list of biodiversity monitoring needs (adapted from Pocock et al. [44]) Total number of times selected in top 10 Biological recorder (n = 2) Consultant (n = 2) Government (n = 7) NGO (n = 5) Researcher (n = 9) Other expertise (n = 2) Design There is standardised methodology and protocols to ensure consistency 18 - 2 (100%) 4 (57%) 4 (80%) 7 (78%) 1 (50%) Human resource Mentoring, training and support for contributors is provided 18 2 (100%) 1 (50%) 5 (71%) 3 (60%) 5 (56%) 2 (100%) Design There is national or regional co- ordination 17 2 (100%) 1 (50%) 5 (71%) 3 (60%) 4 (44%) 2 (100%) Human resource There are quality assurance checks undertaken in order to ensure the accuracy of the records 17 2 (100%) 1 (50%) 4 (57%) 3 (60%) 6 (67%) 1 (50%) Human resource There are sufficient contributors with specialist knowledge of their taxa 15 1 (50%) 1 (50%) 4 (57%) 3 (60%) 5 (56%) 1 (50%) Analytical There are appropriate analytical/ statistical approaches to measure trends from monitoring data 14 - 1 (50%) 2 (29%) 4 (80%) 5 (56%) 2 (100%) Technological There are data systems (e.g. online) for efficient data capture and storage 14 1 (50%) 2 (100%) 3 (43%) 2 (40%) 5 (56%) 1 (50%) Human resource There is sustained participation 12 2 (100%) - 2 (29%) 2 (40%) 5 (56%) 1 (50%) Design/Human resource There is wide coverage across the country/region, e.g. covering remote and well-populated areas 11 1 (50%) - 1 (14%) 3 (60%) 5 (56%) 1 (50%)

Design There are suitable field sampling methods that are accurate/efficient 11 - 1 (50%) 4 (57%) 3 (60%) 2 (22%) 1 (50%) Other resource There are suitable and accessible identification guides 11 2 (100%) 1 (50%) 3 (43%) 1 (20%) 3 (33%) 1 (50%) Analytical Change is reported at appropriate intervals 10 - 1 (50%) 1 (14%) 2 (40%) 6 (67%) - Human resource There are sufficient contributors 10 2 (100%) - 5 (71%) 1 (20%) 1 (11%) 1 (50%) Design ‘Important’ or ‘indicator’ species have been identified 10 - - - 3 (60%) 5 (56%) 2 (100%) Analytical There is access to analytical expertise to measure trends from monitoring data 10 - - 3 (43%) 1 (20%) 5 (56%) 1 (50%) Human resource There is appropriate feedback to participants on survey results and findings 9 2 (100%) 1 (50%) 2 (29%) 1 (20%) 2 (22%) 1 (50%) Design Communicate the objectives of monitoring 9 2 (100%) 2 (100%) 2 (29%) 2 (40%) 1 (11%) - Design/Human resource There is extra effort on protected areas, e.g. Natura 2000 sites 9 - - 2 (29%) 3 (60%) 3 (33%) 1 (50%) Design There is a scientific scheme design (such as stratified or randomised site selection) for statistical rigour 8 - - 1 (14%) 2 (40%) 3 (33%) 2 (100%) Analytical Change is reported on an annual basis 7 - 2 (100%) 1 (14%) - 3 (33%) 1 (50%) Design/Human resource There is extra effort on priority species and habitats 6 1 (50%) 1 (50%) 1 (14%) 2 (40%) 1 (11%) - Design/Human resource Recorders collect supplementary data (such as characteristics of the habitat, soil or weather)

5 - - - 1 (20%) 3 (33%) 1 (50%) Technological/ Human resource The data from monitoring schemes are widely disseminated 5 - 1 (50%) 1 (14%) - 3 (33%) - (Continued) PLOS ONE Expert-elicitation to prioritise biodiversity monitoring PLOS ONE | https://doi.org/10.1371/journal.pone.0256777 March 24, 2022 6 / 20