TROPHIC STRUCTURE VARIATIONS OF FISH COMMUNITIES ACROSS PHYSICOCHEMICAL GRADIENTS IN THE SCIOTO RIVER, OHIO
Trophic structure constitutes one of the main attributes of ecological communities. Here, we used stable-isotope analyses (13C and 15N) to characterize variability in trophic structure of fish assemblages at 12 reaches of the 6th-order Scioto River system (Ohio, USA). Trophic position ranged from 2.21 to 4.35 across study reaches, with the highest trophic position (i.e., food-chain length) ranging from 3.66 to 4.35. Across all species, trophic position was not related to mean body size, but a positive correlation emerged for carnivores, indicating they are strongly size-structured. For omnivores, we found a weak negative correlation. Both mean trophic position and the relationship between trophic position and body size varied by physicochemical features such as channel width and nutrient concentrations, suggesting that human activities can strongly alter riverine trophic structure and the functions it mediates.
Carlos Cáceres (Primary Presenter/Author), The Ohio State University, firstname.lastname@example.org;
S. Mažeika P. Sullivan (Co-Presenter/Co-Author), The Ohio State University, email@example.com;
Adam Kautza (Co-Presenter/Co-Author), Massachusetts Division of Fisheries and Wildlife, firstname.lastname@example.org;