Isotopic trophic guild structure of a diverse subtropical South American fish community

• DOI: 10.1111/eff.12002
• Publication Date: 2012-08-24T06:49:43Z
• Authors: Edward D. Burress; Alejandro Duarte; Michael M. Gangloff; Lynn Siefferman
• Keywords: Guild; Omnivore; Piscivore; Isotope Analysis

Abstract Characterization of food web structure may provide key insights into ecological function, community or population dynamics and evolutionary forces in aquatic ecosystems. We measured stable isotope ratios 23 fish species from the Rio Cuareim, a fifth‐order tributary Uruguay basin, major drainage subtropical South America. Our goals were to (i) describe structure, (ii) compare trophic segregation at guild taxonomic scales (iii) estimate relative importance basal resources supporting biomass. Although community‐level isotopic overlap was high, guilds groups can be clearly differentiated using ratios. Omnivore herbivore display broader δ 13 C range than insectivore piscivore guilds. The chain consists approximately three levels, most fishes are supported by algal carbon. Understanding important for future conservation programs river systems identifying top predators, taxa that occupy unique roles directly engage resources.