Roberts Patrick, Blumenthal Scott A, Dittus Wolfgang, Wedage Oshan, Lee-Thorp Julia A
Max Planck Institute for the Science of Human History, Jena, Germany.
Research Laboratory for Archaeology and the History of Art, School of Archaeology, University of Oxford, Oxford, UK.
Am J Primatol. 2017 Jun;79(6). doi: 10.1002/ajp.22656. Epub 2017 Mar 27.
Stable isotope analysis of primate tissues in tropical forest contexts is an increasingly popular means of obtaining information about niche distinctions among sympatric species, including preferences in feeding height, forest canopy density, plant parts, and trophism. However, issues of equifinality mean that feeding height, canopy density, as well as the plant parts and plant species consumed, may produce similar or confounding effects. With a few exceptions, researchers have so far relied largely on general principles and/or limited plant data from the study area as references for deducing the predominant drivers of primate isotope variation. Here, we explore variation in the stable carbon (δ C), nitrogen (δ N), and oxygen (δ O) isotope ratios of 288 plant samples identified as important to the three primate species from the Polonnaruwa Nature Sanctuary, Sri Lanka, relative to plant part, season, and canopy height. Our results show that plant part and height have the greatest effect on the δ C and δ O measurements of plants of immediate relevance to the primates, Macaca sinica, Semnopithecus priam thersites, and Trachypithecus vetulus, living in this monsoonal tropical forest. We find no influence of plant part, height or season on the δ N of measured plants. While the plant part effect is particularly pronounced in δ C between fruits and leaves, differential feeding height, and plant taxonomy influence plant δ C and δ O differences in addition to plant organ. Given that species composition in different regions and forest types will differ, the results urge caution in extrapolating general isotopic trends without substantial local baselines studies.
对热带森林环境中灵长类动物组织进行稳定同位素分析，正日益成为一种获取有关同域物种生态位差异信息的常用方法，这些信息包括取食高度偏好、森林冠层密度、植物部位以及营养类型。然而，等效性问题意味着取食高度、冠层密度以及所消耗的植物部位和植物种类，可能会产生相似或混淆的影响。除了少数例外情况，研究人员目前主要依赖一般原则和/或研究区域内有限的植物数据，作为推断灵长类动物同位素变化主要驱动因素的参考。在此，我们探讨了来自斯里兰卡波隆纳鲁沃自然保护区的288个被确定对三种灵长类动物重要的植物样本的稳定碳（δC）、氮（δN）和氧（δO）同位素比值相对于植物部位、季节和冠层高度的变化。我们的结果表明，植物部位和高度对与生活在这片季风热带森林中的灵长类动物——斯里兰卡猕猴、黑冠叶猴和紫脸叶猴直接相关的植物的δC和δO测量值影响最大。我们发现植物部位、高度或季节对所测植物的δN没有影响。虽然植物部位的影响在果实和叶片之间的δC中尤为明显，但除了植物器官外，不同的取食高度和植物分类学也会影响植物的δC和δO差异。鉴于不同地区和森林类型的物种组成会有所不同，这些结果提醒在没有大量本地基线研究的情况下，推断一般同位素趋势时要谨慎。
