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Day warming, night warming, and the context dependency of trophic cascades
  • Cori Speights,
  • Brandon Barton
Cori Speights
Mississippi State University
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Brandon Barton
Mississippi State University
Author Profile

Peer review status:IN REVISION

11 May 2020Submitted to Ecology and Evolution
14 May 2020Assigned to Editor
14 May 2020Submission Checks Completed
18 May 2020Reviewer(s) Assigned
10 Jun 2020Review(s) Completed, Editorial Evaluation Pending
11 Jun 2020Editorial Decision: Revise Minor

Abstract

Inherent in climate change experiments is the assumption that researchers seek to understand the impacts of contemporary climate change and not the impacts of changes in the abiotic environment that are not predicted to occur. In general, climate warming is expected to be asymmetrical, with a mean increase in temperature that is driven more by warming at night rather than during the day. However, climate warming experiments tend to disproportionately increase daytime temperatures. If day and night warming have different effects on ecosystems, the mismatch in timing may produce misleading inference about the effects of climate change. To better understand how the timing of warming affects species and their interactions, we examined a food chain of lady beetles, aphids and host plants within environmental chambers programmed to simulate four w treatments (ambient, constant warming, day warming, and night warming). Our results show that the timing of warming influences predators and their interactions with prey in several ways. In plant-only treatments, all warming treatments increased plant above-ground biomass. When aphids were added, the positive direct effect of warming on plants disappeared, and night-warming indirectly reduced plant biomass more than the day- and constant-warming treatments. Although our feeding trial experiments found that lady beetles in day-warming treatments consumed the most aphids in a 24 hour period, predators generated a trophic cascade in only the night warming treatment. Our results contributes to mounting evidence predators can mediate the effects of climate warming and that these predators are affected by day and night warming differently.