Fig. 4From: Wintering Swan Geese maximize energy intake through substrate foraging depth when feeding on buried Vallisneria natans tubersRelationship between average Vallisneria natans tuber dry weight density (g/m2) and tuber burial depth at Shengjin Lake, China. Predicted values (solid line) were calculated from back-transformed data on the basis of a quadratic regression on ln-transformed tuber dry weight density valuesBack to article page