Intraspecific Niche Partitioning and Ecosystem State Drive Carbon Pathways Supporting Lake Food Webs

摘要

Individual behavior drives population-level patterns, yet few studies have integrated how intraspecific niche partitioning influences energy pathways that support consumer production across multiple ecosystem states. We used stable isotope analyses to assess the individual foraging behavior of a dominant consumer, yellow perch (Perca flavescens), in a single lake (Oneida Lake, NY) under both eutrophic (1960s) and mesotrophic (2000s) conditions and at different yellow perch densities. We then integrated this data with intensive population surveys to assess how variation in foraging behavior between individuals and lake trophic status interacts to drive energy pathways supporting consumer production. Stable isotope analyses highlight that individual yellow perch varied greatly in their reliance on benthic and pelagic energy pathways even within a given year. At the population-level, benthic reliance increased from 2 to 20% under eutrophic conditions to 30-70% under mesotrophic conditions. At low densities, individual fish primarily selected inshore habitats and were reliant on benthic carbon, increasing population-level reliance on benthic carbon. This pattern was present during both trophic states, but was more pronounced during mesotrophic conditions. Our results highlight that variation in foraging behavior between individuals can affect the integration of benthic and pelagic energy pathways at the population-level, and that this integration is dependent on ecosystem state and consumer population density. We propose that models that incorporate variation between individual consumers across multiple habitats can more accurately represent energy flows within ecosystems.