Stable isotope bi-plots for each year, illustrating the isotopic niche of carp and crayfish.

The black circles represent individual crayfish and the open circles represent individual carp. The lines enclose the standard ellipse area (SEA_c) for each year for both crayfish (solid) and carp (dashed). Mean values of resource points are also shown; benthic FPOM (open square), plant debris (cross), submerged plants (open diamond), chironomids (open triangle) and oligochaetes (asterisk).