A comparison of point-scoring procedures for species prioritization and allocation of seed collection resources in a mountain region

Setting species priorities is commonly based on the assessment of multiple conservation criteria, and point-scoring methods are broadly used for obtaining ranked species lists. However, the implications of different procedures in the performance and application of resulting lists have been scarcely investigated. In this study, we test the effect of using distinct transformation and summarization of criteria for computing ranked lists for species prioritization and allocation of seed collection resources. The study is focused on the Cantabrian Range (Spain), where 127 vascular plants of conservation concern were scored according to four criteria (threat, protection, endemicity and rarity) related to different geographical scales. Four conservation priority indices (CPI) were computed using a combination of (a) ordinal- versus quantile-weighted transformation and (b) mean versus factorial summarization. Quantile transformation and factorial summarization provided a more quantitative CPI. Although the contribution of criteria to the final indices was different under quantile and ordinal transformations, the four CPI were strongly correlated. However, slight differences between indices reflected divergences in the selection of species priorities when low conservation funds are available, and 14 to 32% of the species composition in priority groups changed. Our results suggest that different point-scoring procedures might have high impact on the application of priority lists for selecting conservation targets, especially when different funding scenarios are compared. We also recommend to (1) avoid ordinal scoring methods, (2) use unequally weighted transformations and (3) apply point-scoring methods based on multi-scale criteria for integrating existing lists in biogeographical areas.