A GIS-based policy support tool to determine national responsibilities and priorities for biodiversity conservation

units are related to the focal species distributions and focal areas in regard to the determination of distributions of selected species as “local”, “regional”, or “wide” (for examples see S2 File). In the Polygon Count-Approach, the number of biogeographical units covered by the dis- tribution of the focal species is used to determine whether its distribution is “local,” “regional,” or “wide,” (Fig 7). These class borders are flexible and can be changed to other values for fur- ther analyses. However, we strongly recommend using the standard setting that is described in [1, 7]. Using the count of biogeographical units can be misleading, especially in cases where the environmental conditions change rapidly over space and the overall area of biogeographical units overlapping with the focal area of an endemic species is small. In such cases, it is com- mon to find three or more biogeographical units within a very small area, when only one bio- geographical unit might be found in a similarly sized area in a region with less spatial variability, for example. The alternative approach implemented in the NRA-Tool calculates the real area proportion of the various biogeographical units that overlap with the distribution area of the focal species (S1 and S2 Files). To avoid biased area calculations, this method requires data with adequate spatial resolution in the correct geographical projection. This approach also requires detailed analyses of the resulting statistical distributions of the propor-

tional area by which each biogeographical unit overlaps the distribution of the focal species. The Polygon Area-Approach is still in experimental stage, and most results published so far have used the Polygon Count-Approach with biomes or environmental zones [50]. We recom- mend using the Polygon Count-Approach (PC-A, ‘by Biome count’ option in the menu) described in [1, 7] in calculations for practical applications. With this manuscript, we provide four appendices containing supporting information on the program and its functioning. S1 File illustrates the "User interface”, S2 File gives an exam- ple for the Polygon Count-Approach and Polygon Area-Approach calculations, S3 File Fig 7. The workflow of the National Responsibility Assessment Tool (IUCN: International Union for Conservation of Nature; NR: National Responsibility; CP: Conservation Priority; DPexp: expected distribution proportion, and DPobs: observed distribution proportion). https://doi.org/10.1371/journal.pone.0243135.g007 PLOS ONE GIS-based policy support tool to determine national responsibilities for biodiversity conservation PLOS ONE | https://doi.org/10.1371/journal.pone.0243135 December 3, 2020 12 / 23