Carbon and nitrogen stable isotope analysis of northwest European horse bone and tooth collagen, 40,000 BP-present: Palaeoclimatic interpretations

Carbon and nitrogen stable isotope ratios of bone and tooth dentine collagen from 142 horses were analysed to consider the potential of isotopic analysis of faunal remains as a palaeoenvironmental and palaeoclimatic proxy. A general trend through time towards lighter delta(13)C values was observed, but with an obvious depletion at the Late Glacial/Holocene transition. Horse delta(13)C values appear to track plant delta(13)C. Although phenomenon such as the canopy effect may influence faunal delta(13)C values, we believe that the influence on plants of increasing atmospheric CO2 is the primary factor in the change in faunal delta(13)C values at the Late Glacial/ Holocene transition. A post-glacial depletion in horse delta(15)N values is observed in areas proximal to glacial retreat although no data is available in these areas during the Last Glacial Maximum. Horse delta(15)N values are presumed to reflect plant delta(15)N values. Depleted plant nitrogen may be attributed to a number of factors e.g. water availability, temperature, cycling of nitrogen in the soil, soil nutrient availability (especially phosphorus in the post-glacial period), and the type of mycorrhizal associations formed with plant. These effects may be interrelated, and be linked such that a positive feedback can give a non-linear response to a single parameter. (C) 2004 Elsevier Ltd. All rights reserved.