Temporal coincidence of environmental stress events modulates predation rates

Abstract

Climate warming experiments generally test the ecological effects of constant treatments while neglecting the influence of more realistic patterns of environmental fluctuations. Thus, little is known regarding how the temporal interaction between multiple episodes of thermal stress influences biotic interactions. We measured the sensitivity of predation rate in an intertidal sea star to changing levels of temporal coincidence of underwater and aerial thermal stress events. In laboratory trials, we controlled for intensity, variance and temporal patterning of both underwater and aerial body temperature. Predation rate decreased as underwater and aerial thermal stress episodes became temporally non-coincident, despite a similar intensity and variance among treatments. Experiments under constant conditions were a poor predictor of more complex environmental scenarios because of these strong temporal interactions. Such temporal interactions may be widespread in various ecosystems, suggesting a strong need for empirical studies and models that link environmental complexity, physiology, behaviour and species interactions.