Horizon 1 1 17 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES Ecology Letters e70256 [11 p.] biomass-driven competition hypothesis environmental filtering eutrophication functional traits juvenile bottleneck lakes more individuals hypothesis negative species associations species evenness Yangtze River CINE: YANGTSE COURS D'EAU 2025 fdi:010095513 ENG Ecology Letters 1461-023X ISI:001611433300001 11 10.1111/ele.70256 https://www.documentation.ird.fr/hor/fdi:010095513 https://www.documentation.ird.fr/intranet/publi/2025-12/010095513.pdf 28 Horizon (IRD) Understanding the productivity-diversity relationship is central in ecology. While hypotheses exist for explaining positive and negative monotonic trends, they have never been combined into one model to account for hump-shaped patterns. Here, we propose a unified model integrating the more-individuals, biomass-driven competition and environmental filtering hypotheses. Analyzing fish communities along a eutrophication gradient, we reconstructed the observed hump-shaped curve between productivity and species richness. Two productivity-related variables explained richness: community size (positive effect) and zooplanktivorous fish biomass (negative effect). Zooplanktivores, overly favored by high productivity, likely competed with juvenile stages of other species for zooplankton, leading to species exclusions. This offers rare evidence for intensified species interactions along a productivity gradient in animal communities. Competition-driven loss thus precedes stress-induced losses (e.g., hypoxia), offering potential for early-warning protocols to monitor eutrophication. 020 ; 036 ; 082 UR276 Chine