Resolving temporal variation in vertebrate diets using naturally occurring stable isotopes
Resolving temporal variation in vertebrate diets using naturally occurring stable isotopes
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DOI：
10.1007/s00442-005-0118-0
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发表时间：
2005-08-01
期刊：
影响因子：
2.7
通讯作者：
Angerbjörn, A
中科院分区：
文献类型：
--
作者：
Dalerum, F;Angerbjörn, A
食物的时间变化的评估对于我们理解许多脊椎动物的生态学是重要的。动物组织中天然存在的稳定同位素的比率是源元素和组织特异性分馏过程的组合，因此可以揭示饮食信息。我们回顾了三种不同的方法，已被用来解决通过稳定同位素分析的时间饮食变化。最直接的方法是比较随时间采样的同一类型组织的样本。这种方法适合于解决长期或短期的饮食变化，这取决于采样制度和采样的组织。第二，可以比较具有不同代谢率的组织。由于特定组织中的元素在特定于其代谢率的时间跨度内被同化，因此具有不同代谢率的组织将反映不同时期的饮食记录。第三，对具有渐进生长的组织（如毛发、羽毛、爪子和牙齿）的切片进行比较，将揭示时间变化，因为这些组织将按时间顺序保留同位素值。后两种方法主要适用于解决有关中期和短期饮食变化的问题。组织特异性代谢率的知识，决定了特定组织的分子周转，是所有这些比较的核心重要性。如果要解决有关源元素的具体假设，则源和测量目标之间的同位素分馏的估计是重要的。如果要比较不同的组织，就必须估计同位素分馏，或至少估计不同组织之间的分馏差异。我们敦促更多的实验室实验，旨在提高我们的理解差异同化的饮食成分，同位素分馏和代谢途径。我们进一步鼓励对爬行动物和两栖动物进行更多的研究，通常更多的研究利用具有不同周转率的多种组织。
Assessments of temporal variation in diets are important for our understanding of the ecology of many vertebrates. Ratios of naturally occurring stable isotopes in animal tissues are a combination of the source elements and tissue specific fractionation processes, and can thus reveal dietary information. We review three different approaches that have been used to resolve temporal diet variation through analysis of stable isotopes. The most straightforward approach is to compare samples from the same type of tissue that has been sampled over time. This approach is suited to address either long or short-term dietary variation, depending on sample regime and which tissue that is sampled. Second, one can compare tissues with different metabolic rates. Since the elements in a given tissue have been assimilating during time spans specific to its metabolic rate, tissues with different metabolic rates will reflect dietary records over different periods. Third, comparisons of sections from tissues with progressive growth, such as hair, feathers, claws and teeth, will reveal temporal variation since these tissues will retain isotopic values in a chronological order. These latter two approaches are mainly suited to address questions regarding intermediate and short-term dietary variation. Knowledge of tissue specific metabolic rates, which determine the molecular turnover for a specific tissue, is of central importance for all these comparisons. Estimates of isotopic fractionation between source and measured target are important if specific hypotheses regarding the source elements are addressed. Estimates of isotopic fractionation, or at least of differences in fractionation between tissues, are necessary if different tissues are compared. We urge for more laboratory experiments aimed at improving our understanding of differential assimilation of dietary components, isotopic fractionation and metabolic routing. We further encourage more studies on reptiles and amphibians, and generally more studies utilizing multiple tissues with different turnover rates.