Abstract
The nonconsumptive effects of predators on prey include behavioral, physiological, and life-history changes that reduce the risk of predation but have associated energetic or fitness costs to prey individuals and populations. Biologists have documented such changes for a wide array of predator–prey interactions in a variety of ecosystems; however, the energetic cost of nonconsumptive effects to prey populations has rarely been measured directly. Using a reach-scale manipulation of a naturally-fishless stream, we added chemical cues produced by live Brook Trout (Salvelinus fontinalis Mitchill, 1814) to simulate the presence of trout predation risk, and we quantified the impact of nonconsumptive effects on the secondary production of mayfly prey in the stream. The addition of trout chemical cues reduced the secondary production of larval Baetis mayflies in the treatment reach by 17% compared to an upstream, unmanipulated reference reach. This reduction was driven by smaller body size and earlier emergence of mayflies from the reach with added predator cues. The nonconsumptive effects of a predator can consequently reduce the flux of energy through a dominant stream invertebrate by altering individual lifehistory and development patterns. Furthermore, quantifying the population-level impact of nonconsumptive effects enables understanding the extent to which these widespread predator effects shape food-web dynamics and ecosystem processes.
| Original language | English |
|---|---|
| Pages (from-to) | 549-558 |
| Number of pages | 10 |
| Journal | Freshwater Science |
| Volume | 39 |
| Issue number | 3 |
| DOIs | |
| State | Published - Sep 1 2020 |
Funding
We thank S. Hale, W. Brown, H. Griscom, G. Aldridge, P. Mudrak, T. Niekum, K. Barnes, C. Bell, E. Eakin, M. Carpenter, N. Spackman, K. Porter, and K. Brown for help in the field and in the lab. S. Hale deserves special thanks for tirelessly hiking more than 60,000 vertical feet to help keep the field experiment running. We are grateful to the Rocky Mountain Biological Laboratory and the Gunnison National Forest for access to Rock Creek. D. Doak, C. Martínez del Rio, T. Collier, A. Benke, and an anonymous reviewer provided comments that greatly improved the manuscript. V. Leshyk created the illustration in Fig. 1. This research was funded by the University of Wyoming’s School of Environment and Natural Resources, Department of Zoology and Physiology, and Program in Ecology through NSF grant EPS-0447681. Additional support came from NSF grant DEB-0516035 to B. L. Peckarsky and A. R. McIntosh and from the American Museum of Natural History, Colorado Mountain Club Foundation, Sigma Xi Scientific Research Society, Rocky Mountain Biological Laboratory, Wyoming NASA Space Grant Consortium, and Northern Arizona University’s Center for Ecosystem Science and Society.
| Funders | Funder number |
|---|---|
| Rocky Mountain Biological Laboratory | |
| DEB-0516035, EPS-0447681 | |
| American Museum of Natural History | |
| Northern Arizona University | |
| SIGMA Clermont |
Keywords
- Baetis
- Field experiment
- Mayfly
- Nonconsumptive effects
- Predator–prey interactions
- Risk effects
- Salvelinus fontinalis
- Secondary production
- Trout