Does variation in stable isotope values decrease at higher trophic positions?
Bump, Joseph*,1, Fox-Dobbs, Kena2, Peterson, Rolf 1, Koch, Paul2, Vucetich, John1, Bada, Jeffrey3, 1 Michigan Technological University, Houghton, MI, USA2 University of California – Santa Cruz, Santa Cruz, CA, USA3 Scripps Institute of Oceanography, La Jolla, CA, USA ABSTRACT- Theoretically, animals at higher trophic positions should exhibit less isotopic variation than lower trophic position species by effectively increasing sample size: a single predator eats lots of herbivores, which in turn have eaten many primary producers that have grown under dynamic conditions (i.e. trophic integration). If so, isotopic chronologies derived from upper trophic position species could arguably provide more precise proxies of environmental change and aid food web analysis. However, consumer diet breadth and variable tissue turnover rates could mask integration patterns. We tested this theory by experimentally analyzing how differences in atmospheric 13C values are transferred across three trophic l
