Resource pulses are infrequent, large magnitude, and short duration events of increased resource availability. They include a diverse set of extreme events that occur in a wide range of ecosystems, but identifying general patterns among the diversity of pulsed resource phenomena in nature remains an important challenge. Here, we present a meta-analysis of resource pulse-consumer interactions that addresses four key questions: 1) Which characteristics of pulsed resources best predict their effects on consumers? 2) Which characteristics of consumers best predict their responses to resource pulses? 3) How do the effects of resource pulses differ in different ecosystems? 4) What are the indirect effects of resource pulses in communities? We built a dataset of 189 pulsed resource-consumer interactions described in a wide range of systems around the world. We developed a metric based on log response ratios in order to compare the proportional effects of resource pulses across disparate systems, and conducted multilevel regression analyses to examine how variation in the characteristics of resource pulses affects the magnitude, duration and timing of consumer responses.
Results/Conclusions
Our results suggest that resource trophic levels, the duration of pulsed resources and the reproductive or aggregative mechanisms of consumer responses are significant predictors of consumer response magnitude; consumer generation time and body mass showed weaker effects. Larger consumer body sizes were correlated with more persistent consumer responses to resource pulses, and reproductive responses were more persistent than aggregative responses. Aquatic systems showed shorter temporal lags between peaks of resource availability and consumer response, compared to terrestrial systems; temporal lags were also shorter in smaller consumers compared to larger consumers. The magnitude of consumer responses relative to their resource pulses was generally smaller for the direct consumers of primary resource pulses, compared to the responses of consumers at greater trophic distances from the initial resource pulse, though this dataset showed both attenuating and amplifying indirect effects in specific systems. We consider the mechanistic processes behind these patterns, and their implications for the ecology of resource pulses.
