The Application of Multi-Dimensional Isotopic Data to Resource Use and Niche Modelling of Aquatic Communities

Stable isotope analysis is a commonly employed method used to infer the foraging ecology of aquatic organisms; stable isotope ratios often allow long-term insights into feeding patterns that would otherwise be difficult to assess. The development of quantitative models for modeling niche space and resource use (i.e. the consumption of particular resource types) has increased the inferential power of isotope analyses. Recent models based on a Bayesian framework incorporate uncertainty within and among groups of study organisms, and allow ecologists to investigate proportional contributions of prey to predator diet, habitat use, isotopic niche size, and isotopic niche overlap. These models are most frequently based on δ¹³C and δ¹⁵N isotope ratios, however, and in complex communities the use of only two isotopes may limit the discrimination power and utility of end results. We will address the development and implementation of multi-dimensional resource use models for niche space and overlap (e.g. nicheROVER) and diet mixing models (e.g. SIAR, MixSIAR). We suggest that the application of these multi-dimensional modelling techniques allow us to use n-dimensional foraging data to increase the inferential power of stable isotopes in aquatic systems.