Page 48 - GIS for Science, Volume 3 Preview

THE MAP OF BIODIVERSITY IMPORTANCE
Individual habitat models can be used in many practical ways to advance species management and conservation, including guiding field inventories, identifying partners in shared stewardship of a species, avoiding conflicts in land use planning, and informing the sustainability practices of agriculture and forestry. When analyzed in aggregate, as for the MoBI project, habitat models can reveal hot spots of species imperilment, offering new insights into opportunities for conservation.
MoBI focused on species from an unprecedented diversity of taxonomic groups (vertebrates, vascular plants, freshwater mussels and crayfish, and pollinating bumblebees, butterflies, and skippers) that face a high degree of imperilment. The inclusion of invertebrates and plants beyond trees is significant, as they have previously been excluded from continental conservation prioritizations due to a lack of comprehensive data. MoBI is actually a series of maps, with different products designed to meet different information needs:
Species richness: Species richness is simply a count of the number of imperiled species with modeled habitat in a grid cell. While intuitive,
it can be misleading when used to identify areas of high conservation significance. By definition, the rarest species have small distributions and are thus unlikely to co-occur with other imperiled species. Species richness can identify where at-risk species are on the landscape, but high values do not necessarily correspond with areas where conservation need is greatest.
Range-size rarity: Range-size rarity (RSR) considers the overall extent
of a species’ range. This is a common metric in spatial conservation analyses. RSR recognizes the inverse relationship between range size and opportunities for conservation interventions. Each species is assigned
an RSR score equal to the inverse of the total area mapped as suitable habitat, and those scores are summed for each species occurring in a grid cell. Higher values identify areas where species with small ranges (and thus fewer conservation opportunities) are likely to occur; the presence of multiple restricted-range species contributes to higher scores.
Protection-weighted range-size rarity: Protection-weighted range size rarity (PWRSR) maps combine information on range-size rarity and the degree to which habitat for the species is protected. We defined protected habitat as that occurring within protected areas managed for biodiversity (in other words, GAP Status 1 and 2 lands in the USGS Protected Areas Database; PAD-US 2.0). Each species was assigned a PWRSR score equal to the product of RSR and the percent of habitat that is unprotected.
The PWRSR raster sums these scores for all species with habitat in a cell to identify areas of greatest conservation need. Higher scores depict areas where multiple narrow-range imperiled species fall outside current protected areas; it is a road map to preventing extinctions.
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