title: Prey diversity as a driver of resource partitioning between river-dwelling fish species.
abstract: Although food resource partitioning among sympatric species has often been explored in riverine systems, the potential influence of prey diversity on resource partitioning is little known. Using empirical data, we modeled food resource partitioning (assessed as dietary overlap) of coexisting juvenile Atlantic salmon (Salmo salar) and alpine bullhead (Cottus poecilopus). Explanatory variables incorporated into the model were fish abundance, benthic prey diversity and abundance, and several dietary metrics to give a total of seventeen potential explanatory variables. First, a forward stepwise procedure based on the Akaike information criterion was used to select explanatory variables with significant effects on food resource partitioning. Then, linear mixed-effect models were constructed using the selected explanatory variables and with sampling site as a random factor. Food resource partitioning between salmon and bullhead increased significantly with increasing prey diversity, and the variation in food resource partitioning was best described by the model that included prey diversity as the only explanatory variable. This study provides empirical support for the notion that prey diversity is a key driver of resource partitioning among competing species.
authors.affiliation: Department of Arctic and Marine Biology Faculty of Biosciences Fisheries and Economics UiT The Arctic University of Norway Tromsø Norway; Department of Zoology, Genetics and Physical Anthropology Faculty of Biology University of Santiago de Compostela Santiago de Compostela Spain.
authors.forename: Javier
authors.identifier: 0000-0001-9684-4774
authors.initials: J
authors.lastname: Sánchez-Hernández
authors.affiliation: Department of Arctic and Marine Biology Faculty of Biosciences Fisheries and Economics UiT The Arctic University of Norway Tromsø Norway.
authors.forename: Heidi-Marie
authors.initials: HM
authors.lastname: Gabler
authors.affiliation: Department of Arctic and Marine Biology Faculty of Biosciences Fisheries and Economics UiT The Arctic University of Norway Tromsø Norway.
authors.forename: Per-Arne
authors.initials: PA
authors.lastname: Amundsen
keywords: biodiversity; coexistence; dietary overlap; interindividual variation; mixed models; niche theory