Data from: How do freshwater prey respond to combinations of predation risk and salinity?

Freshwater salinization is a growing problem worldwide and negatively
affects many freshwater organisms. Many of the prior experiments studying
the effects of salinity on freshwater organisms have examined the effects
of salinity in isolation from natural stressors such as predation risk.
However, stressors such as predation risk can synergistically interact
with many pollutants to affect prey survival and growth, so it is
important to determine if it interacts with salt pollution. In this
experiment, we looked for interactive effects of salinity and predation
risk on freshwater snails using a full-factorial mesocosm experiment that
crossed four salt concentrations (no added salt, 250 mg Cl- /L, 500 mg
Cl-/L, and 1000 mg Cl-/L) with three predator regimes (no predator,
crayfish cues, and water bug cues). Snails were raised in the mesocosms
from juveniles to reproductively mature adults, and we measured their
survival, mass, reproduction, and shell morphology. We discovered a
synergistic effect of salinity and predation risk on the survival of
snails at the highest salt concentration. At the highest salinity, adding
crayfish cues caused a 66% increase in snail mortality, whereas adding
water bug cues caused a 143% increase in snail mortality. In contrast, the
effects of predation risk and salinity on snail mass, reproduction, and
shell morphology were additive. Our results suggest that experiments
testing salinity in isolation from other stressors may underestimate the
full impact of salt pollution in freshwater environments.