Incorporating stable isotopes into a multidisciplinary framework to improve data inference and their conservation and management application

Abstract

Through its ability to address complex ecological questions and the possibility of analysing large sample sizes to understand population-level processes, the use of stable isotope analysis (δ¹³C and δ¹⁵N) has grown rapidly in recent years. Importantly, it is now becoming an accepted tool to derive data for conservation and management planning at the species, community and ecosystem levels. With this acceptance, however, the stable isotope research community faces new challenges to ensure that data are interpreted and presented effectively to maximise their potential for guiding management. We present a case study on stable isotope trends in the vertebrae of white sharks Carcharodon carcharias to show how multiple plausible explanations could be provided to explain the observed isotopic patterns, a point that is likely ubiquitous among isotope studies in ecology. Based on this, we promote that integrating stable isotope data in a multidisciplinary framework will generate the most reliable data for conservationists and resource managers. If this is not possible, we suggest that the isotope community should be more accepting of presenting multiple possible explanations for trends observed in data, rather than focusing on a single interpretation that could potentially misguide management.

Keywords: carbon isotopes, individualisation, maternal influence, nitrogen isotopes, physiological effects, spatial variation