Reliability of δ13C and δ15N in faeces for reconstructing savanna herbivore diet
Reliability of δ13C and δ15N in faeces for reconstructing savanna herbivore diet
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DOI：
10.1016/j.mambio.2007.12.005
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发表时间：
2009-01-01
影响因子：
1.6
通讯作者：
Codron, Jacqui
中科院分区：
文献类型：
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作者：
Codron, Daryl;Codron, Jacqui
我们通过审查源自对南非克鲁格国家公园有蹄类动物为期 3 年的研究的广泛数据库，测试了草食动物粪便 Delta C-13 和 Delta N-15 值在重建饮食方面的可靠性。粪便是饮食稳定同位素研究的有用材料，因为它们在很短的时间尺度内记录饮食周转，并且采样是非侵入性的。然而，粪便同位素替代物的有效性可能会受到质疑，因为它们仅代表未消化的食物残渣。克鲁格公园的结果证实，自由放养的食肉动物的粪便 Delta C-13 与 C-3 喂养一致，食草动物的粪便是 C-4，而混合饲养的粪便则处于中间状态。尽管各自的范围不重叠，但食草动物和食草动物的粪便增量 C-13 在空间和时间上存在显着差异（类似于 2.0-4.0%o）。我们证明，这种变异的大部分（大约 70%）可以分别归因于 C-3 和 C-4 植物的 Delta C-13 中相应的变异模式。强化了粪便同位素替代饮食的保真度，但强调需要控制植物 Delta C-13 变异的混合模型，以实现准确的饮食重建。气候（降雨）和生态生理学对哺乳动物 Delta N-15 丰度变化影响的预测在粪便中并不存在。相反，粪便 Delta N-15 跟踪植物 Delta N-15 的变化，进一步分离主要是由于膳食蛋白质的变化（由 %N 反映）。控制这些影响，我们表明双同位素多源混合模型（Isosource）可以将非洲稀树草原食草动物的饮食重建扩展到简化的 C-3/C-4 区别之外，尽管需要进一步了解哺乳动物 delta N-15 的变化才能对这种方法更有信心。 (C) 2008 德国Gesellschaft fur Saugetierkunde。由爱思唯尔有限公司出版。版权所有。
We tested the reliability of herbivore faecal delta C-13 and delta N-15 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 delta C-13 consistent with C-3 feeding, grazer faeces are C-4, and mixed-feeder faeces intermediate. Although the respective ranges do not overlap, there is significant variation in faecal delta C-13 of browsers and grazers (similar to 2.0-4.0%o) across space and through time. We demonstrate that most (similar to 70%) of this variation can be ascribed to corresponding patterns of variation in the delta C-13 of C-3 and C-4 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 delta C-13 in order to achieve accurate diet reconstructions. Predictions for the effects of climate (rainfall) and ecophysiology on delta N-15-abundance variations in mammals do not persist in faeces. Rather, faecal delta N-15 tracks changes in plant delta N-15, 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 C-3/C-4 distinctions, although further understanding of variations in mammal delta N-15 are needed for greater confidence in this approach. (C) 2008 Deutsche Gesellschaft fur Saugetierkunde. Published by Elsevier GmbH. All rights reserved.