Landscape-scale hydrologic characteristics differentiate patterns of carbon flow in largeriver food webs

Efforts to conserve, restore, or otherwise manage large rivers and the services they provide are hin-dered by limited understanding of the functional dynamics of these systems. This shortcoming is especially evident with regard to trophic structure and energy flow. We used natural abundances of carbon and nitrogen isotopes to examine patterns of material flow in ten large-river food webs char-acterized by different landscape-scale hydrologic characteristics (low-gradient river, high-gradient river, river stretches downstream of reservoirs, and reservoirs), and tested predictions from three eco-system concepts commonly applied to large-rivers