Do grazer hair and faeces reflect the carbon isotope composition of semi-arid C3/C4 grassland?

Wittmer, M.; Auerswald, K.; Schönbach, Philipp; Schäufele, Rudi; Müller, Katrin; Yang, Hao; Bai, Yongfei; Susenbeth, A.; Taube, F.; Schnyder, H.

doi:10.1016/j.baae.2009.10.007

Cited by 32 publications

(32 citation statements)

References 36 publications

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“…However, we found no indication for such a selection. This finding is consistent with data from carbon isotope analysis, which presented no evidence for selective grazing for C3 or C4 vegetation (Wittmer et al 2010).…”

Section: No Selective Grazingsupporting

confidence: 82%

15N fractionation between vegetation, soil, faeces and wool is not influenced by stocking rate

et al. 2010

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Understanding stable isotope fractionation in trophic networks is important for the interpretation of stable isotope composition of ecosystem components. This work explores the influence of grazing pressure on the nitrogen isotope composition (δ N of wool (from a yearly shearing) reflects vegetation at the whole-year grazing grounds-scale while faeces reflect that of the area grazed within a few days. Stocking rate had no effect on δ 15

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Section: No Selective Grazingsupporting

confidence: 82%

15N fractionation between vegetation, soil, faeces and wool is not influenced by stocking rate

et al. 2010

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“…Similarly, our data do not allow investigation of whether convergence in δ Bearhop et al 2002). We observed even larger between-individual variation amongst rheem gazelles, probably related not only to the short duration of these experiments, but also to differences in digestibility of the C 3 lucerne and C 4 grass components of the diets fed to these animals (Wittmer et al 2010;Codron et al 2011). …”

Section: Discussionmentioning

confidence: 90%

“…Laboratory and field experiments have demonstrated that faecal stable isotope compositions are generally consistent with diet isotope compositions, at least amongst large mammal herbivores (Sponheimer et al 2003;Codron and Codron 2009;Norman et al 2009;Wittmer et al 2010;Codron et al 2011). Yet since faeces are comprised of undigested food remains and various endogenous losses (e.g.…”

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confidence: 99%

Tracking the fate of digesta 13C and 15N compositions along the ruminant gastrointestinal tract: Does digestion influence the relationship between diet and faeces?

et al. 2011

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Faecal stable isotope compositions reflect wildlife diets, if digestive processes along the gastrointestinal tract (GIT) do not alter diet-faeces isotopic relationships in an unpredictable way. We investigated 13 C and 15 N compositions of digesta along the ruminant GIT, using Saanen dairy goats kept on pure grass hay or browse for >20 days. Isotopic changes occurred in the ventral rumen, and in the small intestine, where digesta had significantly higher δ 13 C and δ 15 N (associated with lower C or higher N content, respectively) values relative to other GIT sites. However, effects on isotope fractionation were small (∼1.0‰ for δ 13 C and∼2.0‰ for δ 15 N), and were reversed in the hindgut such that faecal isotope compositions did not differ from the foregut. No other substantial isotopic changes occurred across GIT sites, despite the morphophysiological complexity of the ruminant GIT. We found similarly small differences across GIT components of rheem gazelles (Gazella leptoceros) fed a mixture of C 3 lucerne and C 4 grass, although in this case faeces were N abundance is needed. Finally, we note high levels of isotopic variability between individuals fed the same diets, even accounting for the relatively short duration of the experiments, suggesting an important influence of stochasticity on isotope fractionation.

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“…concerning the selectivity of grazing, the constancy of the relationships between isotopic composition of grazer tissues, and contributions of diet components of differential digestibility (Wittmer et al, 2010). Such assumptions can be and should be validated (Wittmer et al, 2010). A significant advantage of keratinous tissue (horn, hair/wool and hoofs) is given by its homogenous chemical composition, which reduces variation associated with metabolic isotope fractionation that can be significant in chemically heterogeneous tissue.…”

Section: Grazer Tissues As Isotopic Archivesmentioning

confidence: 99%

“…Still, the use of grazer tissue for reconstructions of grassland isotopic chronologies usually rests on a number of assumptions, e.g. concerning the selectivity of grazing, the constancy of the relationships between isotopic composition of grazer tissues, and contributions of diet components of differential digestibility (Wittmer et al, 2010). Such assumptions can be and should be validated (Wittmer et al, 2010).…”

Section: Grazer Tissues As Isotopic Archivesmentioning

confidence: 99%

Progress and challenges in using stable isotopes to trace plant carbon and water relations across scales

et al. 2012

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Abstract. Stable isotope analysis is a powerful tool for assessing plant carbon and water relations and their impact on biogeochemical processes at different scales. Our processbased understanding of stable isotope signals, as well as technological developments, has progressed significantly, opening new frontiers in ecological and interdisciplinary research. This has promoted the broad utilisation of carbon, oxygen and hydrogen isotope applications to gain insight into plant carbon and water cycling and their interaction with the atmosphere and pedosphere. Here, we highlight specific areas of recent progress and new research challenges in plant carbon and water relations, using selected examples covering scales from the leaf to the regional scale. Further, we discuss strengths and limitations of recent technological Published by Copernicus Publications on behalf of the European Geosciences Union. C. Werner et al.: Progress and challenges in using stable isotopesdevelopments and approaches and highlight new opportunities arising from unprecedented temporal and spatial resolution of stable isotope measurements.

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Do grazer hair and faeces reflect the carbon isotope composition of semi-arid C3/C4 grassland?

Cited by 32 publications

References 36 publications

15N fractionation between vegetation, soil, faeces and wool is not influenced by stocking rate

15N fractionation between vegetation, soil, faeces and wool is not influenced by stocking rate

Tracking the fate of digesta 13C and 15N compositions along the ruminant gastrointestinal tract: Does digestion influence the relationship between diet and faeces?

Progress and challenges in using stable isotopes to trace plant carbon and water relations across scales

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