Warming-induced shifts in amphibian phenology and behavior lead to altered predator–prey dynamics
Climate change-induced phenological variation in amphibians can disrupt time-sensitive processes such as breeding, hatching, and metamorphosis, and can consequently alter size-dependent interactions such as predation. Temperature can further alter size-dependent, predator–prey relationships through changes in species’ behavior. We thus hypothesized that phenological shifts due to climate warming would alter the predator–prey dynamic in a larval amphibian community through changes in body size and behavior of both the predator and prey. We utilized an amphibian predator–prey system common to the montane wetlands of the U.S. Pacific Northwest: the long-toed salamander (Ambystoma macrodactylum) and its anuran prey, the Pacific chorus frog (Pseudacris regilla). We conducted predation trials to test if changes in predator phenology and environmental temperature influence predation success. We simulated predator phenological shifts using different size classes of the long-toed salamander representing an earlier onset of breeding while using spring temperatures corresponding to early and mid-season larval rearing conditions. Our results indicated that the predator–prey dynamic was highly dependent upon predator phenology and temperature, and both acted synergistically. Increased size asymmetry resulted in higher tadpole predation rates and tadpole tail damage. Both predators and prey altered activity and locomotor performance in warmer treatments. Consequently, behavioral modifications resulted in decreased survival rates of tadpoles in the presence of large salamander larvae. If predators shift to breed disproportionately earlier than prey due to climate warming, this has the potential to negatively impact tadpole populations in high-elevation amphibian assemblages through changes in predation rates mediated by behavior.
KeywordsAmbystoma Pseudacris Temperature Behavior Size mismatch
This research was founded by a research fellowship from the National Scientific and Technical Research Council Argentina (CONICET). M. Perotti and M. Diéguez helped develop the fellowship project. We would also like to thank the Department of Environmental Science and Policy at the University of California at Davis for support for this project and the Department of Fisheries and Wildlife at Oregon State University for providing the temperature-controlled facilitates. Thanks to J. Urbina and E. Bredeweg for their assistance in the field and experimental work. We thank two anonymous reviewers for constructive comments on an earlier draft of this study. Animals were collected under Oregon Department of Fisheries and Wildlife Special Use Permit no. 025-15 and Oregon State University Animal Care and Use Protocol no. 4356.
Author contribution statement
FJ, AS, TG originally formulated the idea; FJ, LT, TG developed methodology; FJ, LT conducted fieldwork; FJ, PM, LT performed statistical analyses; FJ, LT, PM, TG and AS wrote the manuscript.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
All applicable institutional and/or national guidelines for the care and use of animals were followed.
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