Use of δ13C values to determine vegetation selectivity in East African herbivores

Tieszen, Larry L.; Hein, Dennis D.; Qvortrup, S. A.; Troughton, John H.; Imbamba, S. K.

doi:10.1007/bf00347911

Cited by 167 publications

(74 citation statements)

References 24 publications

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“…Mean 613C values range from near -26%0 for C 3 plants to about -12%o for C 4 species (Smith and Epstein, 1971). This difference in C isotope signature has been used to determine the relative proportions of C 3 and C 4 plants in diets of insect and mammalian herbivores (Boutton et al, 1983;Pinder and Kroh, 1987;Tieszen et al, 1979;Tieszen and Imbamba, 1980), soil organic matter (Dzurec et al, 1985;Tieszen and Boutton, 1989), and aboveground (Ludlow et al, 1976) and root biomasses in species mixtures (Svejcar and Boutton, 1985;Svejcar et al, 1988).…”

Section: Introductionmentioning

confidence: 99%

Determination of root biomasses of three species grown in a mixture using stable isotopes of carbon and nitrogen

1992

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A method is evaluated that employs variation in stable C and N isotopes from fractionations in C and N acquisition and growth to predict root biomasses of three plant species in mixtures. Moench (C4) were grown together in separate, three-species combinations. Surface roots (0-10cm depth) of each species from each of the two combinations were mixed in various proportions, and the relative abundances of lSN and 14N and 13C and 12C in prepared mixtures, surface roots of single species, and roots extracted from the 80-cm soil profile in which each species combination was grown were analyzed by mass spectrometry. An algebraic determination which employed the 613C, % 15N, and C and N concentrations of root subsamples of individual species accounted for more than 95% of the variance in biomass of each species in prepared mixtures with G. max, G. hirsutum, and S. bicolor. A similar analysis demonstrated species-specific differences in rooting patterns. Root biomasses of the C 4 monocots in each combination, S. scoparium and S. bicolor, were concentrated in the upper 20 cm of soil, while those of G. hirsutum and the woody P. glandulosa were largest in lower soil strata. Analyses of stable C and N isotopes can effectively be used to distinguish roots of species which differ in ratios of 15N to ~4N and ~3C to ~2C and thus to study belowground competition between or rooting patterns of associated species with different C and N isotope signatures. The method evaluated can be extended to quantify aboveground and belowground biomasses of component species in mixtures with isotopes of other elements or element concentrations that differ consistently among plants of interest.

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Section: Introductionmentioning

confidence: 99%

Determination of root biomasses of three species grown in a mixture using stable isotopes of carbon and nitrogen

1992

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“…Stable isotopes in feces, which are composed of undigested food matter, gut microbes, digestive secretions, and sloughed epithelial tissues, have been demonstrated in experimental and wild settings to reflect ingested diet in mammalian herbivores and primates (4,(40)(41)(42)(43). Digestive processes along the mammalian gastrointestinal tract do not seem to consistently alter the stable isotopic composition of feces relative to diet (44, 45).…”

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confidence: 99%

Detecting intraannual dietary variability in wild mountain gorillas by stable isotope analysis of feces

Blumenthal

Chritz²,

Rothman

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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We use stable isotope ratios in feces of wild mountain gorillas (Gorilla beringei) to test the hypothesis that diet shifts within a single year, as measured by dry mass intake, can be recovered. Isotopic separation of staple foods indicates that intraannual changes in the isotopic composition of feces reflect shifts in diet. Fruits are isotopically distinct compared with other staple foods, and peaks in fecal δ 13 C values are interpreted as periods of increased fruit feeding. Bayesian mixing model results demonstrate that, although the timing of these diet shifts match observational data, the modeled increase in proportional fruit feeding does not capture the full shift. Variation in the isotopic and nutritional composition of gorilla foods is largely independent, highlighting the difficulty for estimating nutritional intake with stable isotopes. Our results demonstrate the potential value of fecal sampling for quantifying short-term, intraindividual dietary variability in primates and other animals with high temporal resolution even when the diet is composed of C 3 plants.C3 photosynthesis | feeding ecology | great apes | Uganda

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“…Despite the fact that species-specific metabolism would be expected to affect the isotope ratios found in faeces and faecal samples represent only the non-digested plant materials, controlled feeding trials and field based studies have shown an agreement between faecal and dietary  13 C and  15 N in African herbivores (Codron and Codron, 2009;Codron et al, 2005c;Tieszen et al, 1979). We therefore suggest that our relative differences reflect dietary differences between the herbivore species, either in terms of the taxonomic, geographic, or topographic sources of their food, or in physiological differences between the consumed plants.…”

Section: Study Caveats and Future Researchmentioning

confidence: 99%

Interaction patterns within a multi-herbivore assemblage derived from stable isotopes

Miranda

Dalerum

Parrini

2014

Ecological Complexity

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The ecological effects of consumer guilds are strongly driven by the relative resource use of included species. Here we use stable isotopes in faecal samples from 6 cooccurring mammalian herbivores in an African savanna to identify species-specific trophic niches and detect patterns of interactions between herbivores and their feeding resources. Species-specific foraging strategies were reflected in the faecal  13 C values, with species aligning along both a browser-grazer gradient and a niche breadth gradient. Within the broad foraging strategies outlined by  13 C,  15 N indicated a seasonal shift in resource use for some herbivores. We expected that 13 C isotope niches would overlap in a nested fashion, with the niches of grazers and browsers being included in those of mixed feeders, and that 15 N niches would separate into discrete modules reflecting leguminous and protein content of respective diets. However, the observed structure was more complex, with combined modular and nested patterns of interactions between herbivores and 13 C isotopes. We identified an isolated module comprising eland and its exclusive δ 13C values, and a series of nested structures with a set of specialist herbivores (hartebeest and sable) which δ 13 C values were nested within those of more generalist herbivores (impala, waterbuck and zebra). Networks based on δ 15 N, however, reflected a higher level of overlap in resource use with random patterns in herbivore interactions with resources, and only a significant modular interaction pattern during the dry season. We suggest that the combined modular and nested pattern of δ 13 C interactions reflect the simultaneous mutualistic and antagonistic characteristics of plant-herbivore interactions. We argue that such interaction patterns could stabilize ecosystems by constraining effects of perturbations to specific modules and by increasing functional redundancy through nested interactions.

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Use of δ13C values to determine vegetation selectivity in East African herbivores

Cited by 167 publications

References 24 publications

Determination of root biomasses of three species grown in a mixture using stable isotopes of carbon and nitrogen

Determination of root biomasses of three species grown in a mixture using stable isotopes of carbon and nitrogen

Detecting intraannual dietary variability in wild mountain gorillas by stable isotope analysis of feces

Interaction patterns within a multi-herbivore assemblage derived from stable isotopes

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