Figure 2. Illustration of the expected relationship between stable isotope values of a predator and its’ prey in mixing space [27,28], employing the Bayesian approach of Jackson et al. [29], centered on multivariate ellipse based metrics.

In choosing discrimination factor (∆¹⁵N and ∆¹³C) values, it would be expected that the δ¹⁵N and δ¹³C values of the predator after adjustment to specific ∆¹⁵N and ∆¹³C values should overlay or fall within the range of δ¹⁵N values of the PP it consumes (see Table 2), indicating a best-fit scenario between predator and prey [ellipses represent prey (black) and predator (gray) respectively]. Black points represent δ¹³C and δ¹⁵N values of a predator, gray points (light and dark) represent adjusted-δ¹³C and adjusted-δ¹⁵N values with two different ∆¹⁵N and ∆¹³C values. White shapes represent mean (± variance) of prey species.