U.S. freshwater mussel occurrence data

Natural history collections are uniquely positioned to chronicle biodiversity changes across time and space and are a fundamental data source in taxon-based research and conservation. With over 90 species listed under the Endangered Species Act, freshwater mussels are one of the most imperiled animal assemblages in the United States and are the focus of considerable conservation efforts. Unfortunately, natural history collections data are often underleveraged in taxon-based conservation efforts because much of the data are decentralized and nonstandard, and thus, difficult to access and analyze. Our objective herein is to synthesize, standardize, and enrich digitized US freshwater mussel collections data to better suit the needs of conservation stakeholders. We aggregated specimen records from 45 US natural history collections and enriched these records by programmatically standardizing taxonomic information, flagging potentially problematic records, and joining records with freshwater-specific spatial frameworks and their associated hydrological metadata. The assembled dataset includes 408,770 records from 302 species and 1,540 hydrological units (8 digit-level). Using these enriched records, we estimated ecological attributes for over 280 freshwater mussel species including aspects of range size and hydrological preferences. Listed species had significantly fewer occurrences, smaller area of occupancy, and experienced greater declines in area of occupancy in comparison to non-listed species. Listed species also had a higher stream order preference and discharge preference than non-listed species. The synthesized, standardized, and enriched natural history collections data and our novel ecological estimates have revealed and corroborated important insights into freshwater mussel diversity, distribution, and decline. Stakeholders can access this data via download or interactively at the companion web app, MusselMapR (https://musselmapr.shinyapps.io/hic_sunt_naiades/).