Species trait diversity sustains multiple dietary nutrients supplied by freshwater fisheries

• Published in: Ecology letters 2023-11, Vol.26 (11), p.1887-1897
• Main Authors: Heilpern, Sebastian A., Herrera‐R, Guido A., Fiorella, Kathryn J., Moya, Luis, Flecker, Alexander S., McIntyre, Peter B.
• Format: Article
• Language: English
• Subjects: Biodiversity; biodiversity loss; biodiversity‐ecosystem function; Biomass; ecological stoichiometry; Ecosystems; Fish; Fisheries; Freshwater fish; functional traits; Nature's contributions to people; Nutrient content; Nutrients; Provisioning; Redundancy; Species diversity
• ISSN: 1461-023X; 1461-0248
• DOI: 10.1111/ele.14299

Species, through their traits, influence how ecosystems simultaneously sustain multiple functions. However, it is unclear how trait diversity sustains the multiple contributions biodiversity makes to people. Freshwater fisheries nourish hundreds of millions of people globally, but overharvesting and river fragmentation are increasingly affecting catches. We analyse how loss of nutritional trait diversity in consumed fish portfolios affects the simultaneous provisioning of six essential dietary nutrients using household data from the Amazon and Tonlé Sap, two of Earth's most productive and diverse freshwater fisheries. We find that fish portfolios with high trait diversity meet higher thresholds of required daily intakes for a greater variety of nutrients with less fish biomass. This beneficial biodiversity effect is driven by low redundancy in species nutrient content profiles. Our findings imply that sustaining the dietary contributions fish make to people given declining biodiversity could require more biomass and ultimately exacerbate fishing pressure in already‐stressed ecosystems. We harness detailed nutrient content data and household consumption information from the Amazon and Mekong, two of Earth's most diverse freshwater fisheries, to analyse how trait diversity sustains the multiple nutritional contributions fish make to people. We find that more diverse fish portfolios can sustain more nourishing diets with less biomass, implying that reductions in fisheries biodiversity could exacerbate fishing pressure in already‐stressed ecosystems. Our integration of fisheries and human dietary needs within a biodiversity‐multifunctionality framework highlights how practical applications of ecological principles to food systems can both address sustainability challenges while advancing key tenants of ecological science.