Number of Fish Species by Freshwater Ecoregion

Number of freshwater fish species, by freshwater ecoregion.

The map of freshwater fish species richness—the number of species present in each ecoregion—was generated from a variety of sources by Abell et al. (2008). Only species using freshwater for at least a portion of their life cycles, as identified using the habitat assignments in FishBase, are included. For the United States, NatureServe provided presence/absence data for individual species, coded to eight-digit hydrologic unit codes (HUCs); these HUC occurrences were then translated into ecoregions, and the data were manually cleaned of erroneous occurrences derived from species introductions and problematic records. For all other ecoregions, species lists were provided by experts based on published literature as well as from gray literature and unpublished sources. Abell et al. (2008) generated data on fish species for some small islands using FishBase and then augmented where possible with information from published literature. For a small number of ecoregions, it was impossible to generate species lists; therefore, richness estimates are provided instead. Extirpated species are included in these tallies, but confirmed extinct species, as determined by the Committee on Recently Extinct Organisms (data provided by Ian Harrison), and introduced and undescribed species are excluded.

These data were displayed in a map published in The Atlas of Global Conservation (Hoekstra et al., University of California Press, 2010). More information at http://nature.org/atlas.