Title: USING STABLE ISOTOPES TO ESTIMATE TROPHIC POSITION: MODELS, METHODS, AND ASSUMPTIONS
Abstract: EcologyVolume 83, Issue 3 p. 703-718 Regular Article USING STABLE ISOTOPES TO ESTIMATE TROPHIC POSITION: MODELS, METHODS, AND ASSUMPTIONS David M. Post, David M. Post Department of Ecology and Evolutionary Biology, Corson Hall, Cornell University, Ithaca, New York 14853 USA. Institute for Ecosystem Studies, Box AB, Millbrook, New York 12545 USA Present address: National Center for Ecological Analysis and Synthesis, 735 State Street, Suite 300, Santa Barbara, California 93101-3351 USA. E-mail: [email protected] for more papers by this author David M. Post, David M. Post Department of Ecology and Evolutionary Biology, Corson Hall, Cornell University, Ithaca, New York 14853 USA. Institute for Ecosystem Studies, Box AB, Millbrook, New York 12545 USA Present address: National Center for Ecological Analysis and Synthesis, 735 State Street, Suite 300, Santa Barbara, California 93101-3351 USA. E-mail: [email protected] for more papers by this author First published: 01 March 2002 https://doi.org/10.1890/0012-9658(2002)083[0703:USITET]2.0.CO;2Citations: 4,188 Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Abstract The stable isotopes of nitrogen (δ15N) and carbon (δ13C) provide powerful tools for estimating the trophic positions of and carbon flow to consumers in food webs; however, the isotopic signature of a consumer alone is not generally sufficient to infer trophic position or carbon source without an appropriate isotopic baseline. In this paper, I develop and discuss methods for generating an isotopic baseline and evaluate the assumptions required to estimate the trophic position of consumers using stable isotopes in multiple ecosystem studies. I test the ability of two primary consumers, surface-grazing snails and filter-feeding mussels, to capture the spatial and temporal variation at the base of aquatic food webs. I find that snails reflect the isotopic signature of the base of the littoral food web, mussels reflect the isotopic signature of the pelagic food web, and together they provide a good isotopic baseline for estimating trophic position of secondary or higher trophic level consumers in lake ecosystems. Then, using data from 25 north temperate lakes, I evaluate how δ15N and δ13C of the base of aquatic food webs varies both among lakes and between the littoral and pelagic food webs within lakes. Using data from the literature, I show that the mean trophic fractionation of δ15N is 3.4‰ (1 sd = 1‰) and of δ13C is 0.4‰ (1 sd = 1.3‰), and that both, even though variable, are widely applicable. A sensitivity analysis reveals that estimates of trophic position are very sensitive to assumptions about the trophic fractionation of δ15N, moderately sensitive to different methods for generating an isotopic baseline, and not sensitive to assumptions about the trophic fractionation of δ13C when δ13C is used to estimate the proportion of nitrogen in a consumer derived from two sources. Finally, I compare my recommendations for generating an isotopic baseline to an alternative model proposed by M. J. Vander Zanden and J. B. Rasmussen. With an appropriate isotopic baseline and an appreciation of the underlying assumptions and model sensitivity, stable isotopes can help answer some of the most difficult questions in food web ecology. Citing Literature Volume83, Issue3March 2002Pages 703-718 This article also appears in:Centennial Special: Notable Papers in ESA History RelatedInformation
Publication Year: 2002
Publication Date: 2002-03-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 5642
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