Several experimental studies have reported that the reduction of snail grazers by crayfish has resulted in a clear increase in periphyton biomass via a trophic cascade (Weber & Lodge, 1990; Lodge et al., 1994; Nystr€om et al., 1999, 2001).
Several experimental studies have reported that thereduction of snail grazers by crayfish has resulted in aclear increase in periphyton biomass via a trophic cascade(Weber & Lodge, 1990; Lodge et al., 1994; Nystr€omet al., 1999, 2001).