U.S. freshwater mussel occurrence data

Natural history collections are uniquely positioned to chronicle
biodiversity change and are a fundamental data source in taxon-based
research and conservation. With 85 species federally protected under the
Endangered Species Act, freshwater mussels are one of the most imperiled
animal assemblages in the United States and are the focus of extensive
conservation efforts. Unfortunately, natural history collections data are
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, enrich, and
distribute 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 410,813 records from 302 species and 1,538 hydrological
units (8 digit-level). Using these enriched records, we estimated
ecological attributes for 286 freshwater mussel species including aspects
of range size and hydrological preferences. Imperiled species had
significantly fewer occurrences, smaller area of occupancy, and
experienced greater declines in area of occupancy than non-imperiled
species. Imperiled species also had higher stream order and discharge
preferences than non-imperiled 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/).