Physical Sciences and Mathematics Commons^™

You Are Not Always What We Think You Eat: Selective Assimilation Across Multiple Whole-Stream Isotopic Tracer Studies, W. K. Dodds, S. M. Collins, S. K. Hamilton, J. L. Tank, S. Johnson, J. R. Webster, K. S. Simon, M. R. Whiles, H. M. Rantala, W. H. Mcdowell, S. D. Peterson, T. Riis, C. L. Crenshaw, S. A. Thomas, P. B. Kristensen, B. M. Cheever, A. S. Flecker, N. A. Griffiths, T. Crowl, E. J. Rosi-Marshall, R. El-Sabaawi, E. Marti

School of Natural Resources: Faculty Publications

Analyses of 21 ¹⁵N stable isotope tracer experiments, designed to examine food web dynamics in streams around the world, indicated that the isotopic composition of food resources assimilated by primary consumers (mostly invertebrates) poorly reflected the presumed food sources. Modeling indicated that consumers assimilated only 33–50% of the N available in sampled food sources such as decomposing leaves, epilithon, and fine particulate detritus over feeding periods of weeks or more. Thus, common methods of sampling food sources consumed by animals in streams do not sufficiently reflect the pool of N they assimilate. Isotope tracer studies, combined with modeling and …