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Analysing the isotopic life history of the alpine ungulates Capra ibex and Rupicapra rupicapra rupicapra through their horns
Author(s) -
Barbosa Inês C. R.,
Kley Maximiliane,
Schäufele Rudi,
Auerswald Karl,
Schröder Wolf,
Filli Flurin,
Hertwig Stefan,
Schnyder Hans
Publication year - 2009
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.4157
Subject(s) - french horn , delta , ungulate , δ13c , isotopes of nitrogen , zoology , stable isotope ratio , chemistry , ecology , nitrogen , biology , physics , habitat , quantum mechanics , acoustics , organic chemistry , astronomy
Abstract The horn of ungulate grazers offers a valuable isotopic record of their diet and environment. However, there have been no reports of the spatio‐temporal variation of the isotopic composition of horns. We investigated patterns of carbon ( δ 13 C) and nitrogen ( δ 15 N) isotopic composition along and perpendicular to the horn axis in Capra ibex and Rupicapra rupicapra rupicapra to assess the effects of animal age, within‐year (seasonal) and inter‐annual variation, natural contamination and sampling position on horn isotope composition. Horns of male C . ibex ( n = 23) and R . r . rupicapra ( n = 1) were sampled longitudinally on the front (only R . r . rupicapra ) and back side and on the surface and sub‐surface. The sides of the R. r. rupicapra horn did not differ in δ 13 C. In both species, the horn surface had a 0.15‰ lower δ 13 C and a higher carbon‐to‐nitrogen (C/N) ratio than the sub‐surface. Washing the horn with water and organic solvents removed material that caused these differences. With age, the δ 15 N of C. ibex horns increased (+0.1‰ year −1 ), C/N ratio increased, and 13 C discrimination relative to atmospheric CO 2 ( 13 Δ) increased slightly (+0.03‰ year −1 ). Geostatistical analysis of one C. ibex horn revealed systematic patterns of inter‐annual and seasonal 13 C changes, but 15 N changed only seasonally. The work demonstrates that isotopic signals in horns are influenced by natural contamination ( δ 13 C), age effects ( 13 Δ and δ 15 N), and seasonal ( δ 13 C and δ 15 N) and inter‐annual variation ( δ 13 C). The methods presented allow us to distinguish between these effects and thus allow the use of horns as isotopic archives of the ecology of these species and their habitat. Copyright © 2009 John Wiley & Sons, Ltd.