DESCRIBING A SPECIES-RICH RIVER FOOD WEB USING STABLE ISOTOPES, STOMACH CONTENTS, AND FUNCTIONAL EXPERIMENTS Chapter uri icon

abstract

  • The importance of using empirically derived stomach contents analysis has increasingly been acknowledged, and together stable isotope ratio and stomach contents analysis can provide detailed descriptions of energy flow through food webs. These approaches, however, do not reveal functional roles of organisms in the web. Samples were analyzed at the Stable Isotope Laboratory at the University of Georgia's Institute of Ecology for determination of percent carbon, percent nitrogen, and stable isotope ratios. A diversity of prey types support individuals of this top predator species, and emphasizes the importance of large sample sizes to characterize this variability. Other sources of information, such as additional isotopes or stomach contents, are needed to further identify the importance of specific resources to secondary consumers. Ratios of stable isotopes indicate that large-bodied piscivores feed relatively low in the food web. The piranha Serrasalmus manueli occupied the highest estimated mean trophic position in the web. A predator's foraging strategy is optimal when it exploits the thermodynamically richest resource possible. Stable isotope ratios are most informative when combined with stomach content analysis. This is especially important in species-rich systems where predators may consume diverse prey items, and it is impossible to identify particular predator-prey interactions from stable isotope ratios alone. 2006 Elsevier Inc. All rights reserved.

author list (cited authors)

  • Layman, C. A., Winemiller, K. O., & Arrington, D. A.

citation count

  • 18

complete list of authors

  • Layman, Craig A||Winemiller, Kirk O||Arrington, D Albrey

Book Title

  • Dynamic Food Webs

publication date

  • January 2005