Representation of three possible ontogenetic niche shift scenarios using stable isotope ratios.

<p>Horizontally adjacent panels represent the same ontogenetic niche shift scenario. (A–C) Multivariate illustration of potential differences in niche width (represented by convex hull polygons), niche position and niche overlap (see text for more details) between two size classes in δ¹³C-δ¹⁵N niche space. (D–F) Univariate representation of niche width (variance of isotope values) and niche position (mean isotopic value) of either δ¹³C or δ¹⁵N between size classes. Closed circles represent isotope data of small individuals and open circles of large individuals. For B & E, this could also be a niche reduction, i.e., small individuals would occupy larger niche width than large individuals. Solid line = constant niche width, dotted line = niche reduction, dashed line = niche expansion; S = small size class, L = large size class. In panel F, solid line = constant variance, dotted line = reduced variance, dashed line = increased variance.