Assessing the Conservation Status, Drivers of Threat and Available Occurrence Records of Sub‐Saharan African Freshwater Molluscs: Gaps and Patterns

ABSTRACT

Freshwater molluscs are key bioindicators of ecosystem health, yet their conservation status and data coverage in sub‐Saharan Africa remain poorly understood. Mollusca is the third most evaluated phylum on the IUCN Red List in Africa, with 1394 species assessed (656 freshwater), of which 39.6% are Least Concern and 12% Critically Endangered. Notably, 22.4% are Data Deficient, signalling major knowledge gaps. This study assessed the availability of freshwater mollusc occurrence records and molecular data across mainland sub‐Saharan Africa. Occurrence records were compiled from the Global Biodiversity Information Facility (GBIF), filtered geographically, taxonomically standardised and linked to IUCN Red List categories. In parallel, cytochrome oxidase I (COI) barcode coverage was evaluated using the Barcode of Life Data System (BOLD). We identified 36,927 occurrence records, with South Africa (6683) and Tanzania (4299) contributing the most data. Sampling effort was strongly clustered in central and southern Africa, revealing pronounced spatial biases. The Democratic Republic of Congo supported the highest number of threatened species, including 10 Critically Endangered and 19 Endangered taxa. Despite this concentration of diversity and threat, only 94 sub‐Saharan freshwater mollusc species possessed COI barcodes, exposing a severe shortfall in molecular reference data. By integrating GBIF occurrences, IUCN assessments and BOLD barcodes, this work jointly evaluates conservation status, data completeness and genetic information for freshwater molluscs in sub‐Saharan Africa. Analyses of geographic, taxonomic and threat‐related patterns exposed critical gaps in occurrence records, inconsistencies in threat documentation and widespread deficiencies in molecular resources. Pollution, habitat modification, invasive species and overharvesting were the most frequently reported threats. Collectively, these findings identify priority regions and taxa for reassessment, enhanced monitoring and strategic expansion of genetic reference libraries, providing a targeted framework to strengthen freshwater mollusc conservation in the region.