A METAANALYSIS OF THE FRESH-WATER TROPHIC CASCADE

The generality of the trophic cascade has been an intensely debated to pic among ecologists. We conducted a meta-analysis of 54 separate encl osure and pond experiments that measured the response of the zooplankt on and phytoplankton to zooplanktivorous fish treatments. These result s provide unequivocal support for the trophic cascade hypothesis in fr eshwater food webs. Zooplanktivorous fish treatments resulted in reduc ed zooplankton biomass and increased phytoplankton biomass. The trophi c cascade was weakly dampened at the level of the phytoplankton. Howev er, the response of the phytoplankton to the trophic cascade was highl y skewed, with very strong responses in slightly more than one-third o f the cases and weak responses in the others.