title: Stable carbon, oxygen, and nitrogen, isotope analysis of plants from a South Asian tropical forest: Implications for primatology.
abstract: 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 (δ13C), nitrogen (δ15N), and oxygen (δ18O) 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 δ13C and δ18O 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 δ15N of measured plants. While the plant part effect is particularly pronounced in δ13C between fruits and leaves, differential feeding height, and plant taxonomy influence plant δ13C and δ18O 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.
authors.affiliation: 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.
authors.forename: Patrick
authors.identifier: 0000-0002-4403-7548
authors.initials: P
authors.lastname: Roberts
authors.affiliation: Research Laboratory for Archaeology and the History of Art, School of Archaeology, University of Oxford, Oxford, UK.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Blumenthal
authors.affiliation: Smithsonian Conservation Biology Institute, Conservation Ecology Center, Front Royal, Washington D.C.|National Institute of Fundamental Studies, Kandy, Sri Lanka.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Dittus
authors.affiliation: Department of History and Archaeology, University of Sri Jayewardenepura, Gangodawila, Nugegoda, Sri Lanka.
authors.forename: Oshan
authors.initials: O
authors.lastname: Wedage
authors.affiliation: Research Laboratory for Archaeology and the History of Art, School of Archaeology, University of Oxford, Oxford, UK.
authors.forename: Julia A
authors.initials: JA
authors.lastname: Lee-Thorp
mesh_terms: D000818:Animals; D002247:Carbon Isotopes / Q000032:analysis; D065928:Forests; D009587:Nitrogen Isotopes / Q000032:analysis; D010103:Oxygen Isotopes / Q000032:analysis; D010945:Plants, Edible; D011323:Primates; D013188:Sri Lanka
chemical_list: D002247:Carbon Isotopes; D009587:Nitrogen Isotopes; D010103:Oxygen Isotopes
keywords: South Asia; diet; plant ecology; primates; stable isotope ecology