Background/Question/Methods Although it is generally understood that climate change is a process involving multiple aspects of the abiotic environment, ecological studies have largely focused on the effects of temperature. These studies have advanced our understanding of how temperature impacts ecological interactions, but these studies have also revealed that the effects of warming are context dependent. Empirical records of the past, as well as climate models that forecast the future, demonstrate that warming is often asymmetrical with either daytime or nighttime temperatures increasing more than the other. However, it is currently unclear if the timing of warming matters and if warming experiments are using realistic treatments. To better understand the effects of asymmetrical warming, I led several experiments using arthropod food webs to determine how daytime, nighttime, and constant warming affects ecological interactions. I also evaluated published experiments that investigated the effects of warming on food webs and predator-prey interactions to describe the extant literature. By pairing this literature review with climate model forecasts for each study location, the frequency of which studies use warming treatments that match forecasts was quantified. This multi-faceted approach allows me to address how timing mediates the effects of warming, and identify ways to move forward.
Results/Conclusions My experiments in different study systems and across different years produced mixed results. In some systems (e.g., spider-grasshopper food chains) there was strong evidence that daytime warming and nighttime warming produced entirely different effects on animal behavior and plant communities. In other systems (e.g., lady beetle-aphid food chains) the results were more mixed. Field studies revealed strong indirect effects of nighttime warming on plant biomass, while lab studies were inconclusive. The mechanisms driving such mixed results remain unknown. The literature review revealed large geographic biases in where experiments were conducted. Although much of earth’s terrestrial ecosystems are forecasted to experience nighttime-dominated warming, most experiments were conducted in places that are forecasted to experience daytime-dominated warming. These studies often used treatments that matched their forecasts, but it remains unclear if the insight gained from those experiments will apply to other areas.