Meeting Abstract

S1-6  Thursday, Jan. 5 11:00 - 11:30  Species interactions in variable environments: How temporal patterns of temperature can influence competitive interactions FEY, SB; Yale University

While climate warming occurs over a background of variation due to cyclical processes and irregular events, the temporal structure of the thermal environment is largely ignored when forecasting the dynamics of interacting species. Ecological theory predicts that high levels of temporal autocorrelation in the environment– relatedness between conditions occurring in close temporal proximity– will favor populations that would otherwise have an average negative growth rate by increasing the duration of favorable environmental periods. Here, I invoke such theory to explain the success of biological invasions and evaluate the hypothesis that sustained periods of high environmental temperature can act synergistically with increases in mean temperature to favor the establishment of non-native species. I present data from a recent field mesocosm experiment that measures the population dynamics of the non-native cladoceran zooplankter Daphnia lumholtzi and a native congener Daphnia pulex in ambient temperature environments (control), warmed with recurrent periods of high environmental temperatures (uncorrelated-warmed), or warmed with sustained periods of high environmental temperatures (autocorrelated-warmed), such that both warmed treatments exhibited the same mean temperature but exhibited different temporal structures of their thermal environments. I interpret the results of this experiment in the context of simple mathematical models to show how alterations in performance can occur alongside increasing temporal autocorrelation, even among environments with the same mean temperature.