Figure 1 Effects of shading and snail biomass on primary
producers. P. crispus shoot
biomass (A) , V. spinulosa biomass (B) ,
periphyton chl a content (C) , and phytoplankton chl a content(D) . S0 indicates full light, S1 indicates
low light intensity under shading.
Lines are fitted by gam functions in package ggplot2, and a solid line
indicates p < 0.05, and a dashed line indicatesp > 0.05. Dot symbol indicates nutrient loading, and
triangles indicate no additional nutrients were added. P values
in the panel indicate a significant effect of shading on the mean of the
response variable.