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Predator-prey interactions in a benthic stream community: a field test of flow-mediated refuges
David D Hart1, Rachel Ann Merz2
1Patrick Center for Environmental Research, Academy of Natural Sciences, 1900 Benjamin Franklin Parkway, Philadelphia, PA 19103-1195, USA Department of Biology, University of Pennsylvania, Philadelphia, PA 19104-6018, USA Fax: 215-299-1079; e-mail: hart@acnatsci.org, , , , , , US.
Oecologia
|March 18, 2017
Summary
High-flow microhabitats offer spatial refuges for black fly larvae, reducing predation by flatworms. These flow-mediated refuges are crucial for understanding predator-prey dynamics in aquatic environments.
Area of Science:
- Ecology
- Aquatic Ecology
- Predator-Prey Dynamics
Background:
- Ecological theory highlights the importance of prey refuges in modifying predation impacts.
- Understanding factors influencing refuge availability is crucial for ecological studies.
- Benthic microhabitats may offer spatial refuges for aquatic invertebrates.
Purpose of the Study:
- To test if high-flow benthic microhabitats serve as spatial refuges for black fly larvae (Simulium vittatum).
- To investigate if these refuges reduce the negative impact of predatory flatworms (Dugesia dorotocephala).
- To examine the influence of current speed and predator abundance on larval black fly populations.
Main Methods:
- A field experiment was conducted in Chester Creek, Pennsylvania.
- Manipulated variations in flatworm abundance and current speed were applied to tile substrates.
- Multiple regression analysis was used to determine relationships between larval abundance, predator abundance, and current speed.
Main Results:
- Flatworm abundance decreased with increasing current speed, suggesting high-flow areas as potential refuges.
- Larval black fly abundance was negatively related to flatworm abundance and positively related to current speed.
- Flow and predators explained 38% of the variation in the rate of change in larval abundance.
Conclusions:
- High-flow microhabitats act as flow-mediated refuges for black fly larvae, reducing predation risk.
- Both direct effects of flow on larvae (feeding rates) and indirect effects (predator reduction) contribute to refuge function.
- The biomechanical principles suggest flow-mediated refuges are common in diverse benthic environments.
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