UZH-Logo

Maintenance Infos

Reliability of δ13C and δ15N in faeces for reconstructing savanna herbivore diet


Codron, D; Codron, J (2009). Reliability of δ13C and δ15N in faeces for reconstructing savanna herbivore diet. Mammalian Biology - Zeitschrift für Säugetierkunde, 74(1):36-48.

Abstract

We tested the reliability of herbivore faecal d13C and d15N values for reconstructing diet through review of an extensive database derived from a 3-year study of ungulates in South Africa’s Kruger National Park. Faeces are a useful material for stable isotope studies of diet because they record dietary turnover at very short time scales, and because sampling is non-invasive. However, the validity of faecal isotope proxies may be questioned because they represent only undigested food remains. Results from Kruger Park confirm that free-ranging browsers have faecal d13C consistent with C3 feeding, grazer faeces are C4, and mixed-feeder faeces intermediate. Although the respective ranges do not overlap, there is significant variation in faecal d13C of browsers and grazers (2.0–4.0%) across space and through time. We demonstrate that most (70%) of this variation can be ascribed to corresponding patterns of variation in the d13C of C3 and C4 plants, respectively, re-enforcing the fidelity of faecal isotope proxies for diet but highlighting a need for mixing models that control for variations in plant d13C in order to achieve accurate diet reconstructions. Predictions for the effects of climate (rainfall) and ecophysiology on 15N-abundance variations in mammals do not persist in faeces. Rather, faecal d15N tracks changes in plant d15N, with further fractionation occurring primarily due to variations in dietary protein (reflected by %N). Controlling for these effects, we show that a dual-isotope multiple source mixing model (Isosource) can extend diet reconstructions for African savanna herbivores beyond simplified C3/C4 distinctions, although further understanding of variations in mammal d15N are needed for greater confidence in this approach.

We tested the reliability of herbivore faecal d13C and d15N values for reconstructing diet through review of an extensive database derived from a 3-year study of ungulates in South Africa’s Kruger National Park. Faeces are a useful material for stable isotope studies of diet because they record dietary turnover at very short time scales, and because sampling is non-invasive. However, the validity of faecal isotope proxies may be questioned because they represent only undigested food remains. Results from Kruger Park confirm that free-ranging browsers have faecal d13C consistent with C3 feeding, grazer faeces are C4, and mixed-feeder faeces intermediate. Although the respective ranges do not overlap, there is significant variation in faecal d13C of browsers and grazers (2.0–4.0%) across space and through time. We demonstrate that most (70%) of this variation can be ascribed to corresponding patterns of variation in the d13C of C3 and C4 plants, respectively, re-enforcing the fidelity of faecal isotope proxies for diet but highlighting a need for mixing models that control for variations in plant d13C in order to achieve accurate diet reconstructions. Predictions for the effects of climate (rainfall) and ecophysiology on 15N-abundance variations in mammals do not persist in faeces. Rather, faecal d15N tracks changes in plant d15N, with further fractionation occurring primarily due to variations in dietary protein (reflected by %N). Controlling for these effects, we show that a dual-isotope multiple source mixing model (Isosource) can extend diet reconstructions for African savanna herbivores beyond simplified C3/C4 distinctions, although further understanding of variations in mammal d15N are needed for greater confidence in this approach.

Citations

20 citations in Web of Science®
20 citations in Scopus®
Google Scholar™

Altmetrics

Downloads

1 download since deposited on 06 Jan 2010
0 downloads since 12 months
Detailed statistics

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:05 Vetsuisse Faculty > Veterinary Clinic > Department of Small Animals
Dewey Decimal Classification:570 Life sciences; biology
630 Agriculture
Language:English
Date:2009
Deposited On:06 Jan 2010 15:33
Last Modified:05 Apr 2016 13:37
Publisher:Elsevier
ISSN:1616-5047
Publisher DOI:https://doi.org/10.1016/j.mambio.2007.12.005
Permanent URL: https://doi.org/10.5167/uzh-25326

Download

[img]
Filetype: PDF - Registered users only
Size: 1MB
View at publisher

TrendTerms

TrendTerms displays relevant terms of the abstract of this publication and related documents on a map. The terms and their relations were extracted from ZORA using word statistics. Their timelines are taken from ZORA as well. The bubble size of a term is proportional to the number of documents where the term occurs. Red, orange, yellow and green colors are used for terms that occur in the current document; red indicates high interlinkedness of a term with other terms, orange, yellow and green decreasing interlinkedness. Blue is used for terms that have a relation with the terms in this document, but occur in other documents.
You can navigate and zoom the map. Mouse-hovering a term displays its timeline, clicking it yields the associated documents.

Author Collaborations