Environmental factors affecting incorporation of terrestrial material into large river food webs

Abstract

AbstractThree enduring conceptual models make predictions regarding the basal production sources supporting the upper food web of rivers: the River Continuum Concept, the Flood Pulse Concept, and the Riverine Productivity Model. Sources of primary production supporting metazoan biomass might best be understood by using a pluralistic approach that views basal sources as a dependent variable and key physicochemical and hydrological factors as independent variables. Here, I review studies in which chemical markers (stable-isotope and fatty-acid analyses) were used to estimate dominant primary producers contributing to consumer biomass in large rivers and evaluate associated independent variables (e.g., hydrologic regime, turbidity, concentration of dissolved organic matter, floodplain vegetation, lateral connectivity, and upstream impoundment) that have been hypothesized to contribute to variation in basal production sources. My review shows that C4 grasses rarely support riverine metazoans and that algae ar...