Book contents
- Frontmatter
- Contents
- Contributors
- Preface
- 1 Cascading trophic interactions
- 2 Experimental lakes, manipulations and measurements
- 3 Statistical analysis of the ecosystem experiments
- 4 The fish populations
- 5 Fish behavioral and community responses to manipulation
- 6 Roles of fish predation: piscivory and planktivory
- 7 Dynamics of the phantom midge: implications for zooplankton
- 8 Zooplankton community dynamics
- 9 Effects of predators and food supply on diel vertical migration of Daphnia
- 10 Zooplankton biomass and body size
- 11 Phytoplankton community dynamics
- 12 Metalimnetic phytoplankton dynamics
- 13 Primary production and its interactions with nutrients and light transmission
- 14 Heterotrophic microbial processes
- 15 Annual fossil records of food-web manipulation
- 16 Simulation models of the trophic cascade: predictions and evaluations
- 17 Synthesis and new directions
- References
- Index
6 - Roles of fish predation: piscivory and planktivory
Published online by Cambridge University Press: 06 August 2010
- Frontmatter
- Contents
- Contributors
- Preface
- 1 Cascading trophic interactions
- 2 Experimental lakes, manipulations and measurements
- 3 Statistical analysis of the ecosystem experiments
- 4 The fish populations
- 5 Fish behavioral and community responses to manipulation
- 6 Roles of fish predation: piscivory and planktivory
- 7 Dynamics of the phantom midge: implications for zooplankton
- 8 Zooplankton community dynamics
- 9 Effects of predators and food supply on diel vertical migration of Daphnia
- 10 Zooplankton biomass and body size
- 11 Phytoplankton community dynamics
- 12 Metalimnetic phytoplankton dynamics
- 13 Primary production and its interactions with nutrients and light transmission
- 14 Heterotrophic microbial processes
- 15 Annual fossil records of food-web manipulation
- 16 Simulation models of the trophic cascade: predictions and evaluations
- 17 Synthesis and new directions
- References
- Index
Summary
Introduction
Understanding the impacts of fish predation on lower trophic levels is a generally important goal (Wootton, 1990). In the special case of our studies, fishes are the reagents of whole-lake experiments. Because many fishes are opportunistic predators capable of complex behavior (Chapters 4 and 5; Hodgson & Kitchell, 1987), manipulation of fish populations may change predation pressure on lower trophic levels in unexpected ways. Therefore, it was essential to measure rates of predation on key food web components during the course of our experiments.
In piscivore-dominated systems, some species of planktivorous fishes may not persist or may be maintained at very low population densities (Tonn & Magnuson, 1982). Juvenile fishes are typically planktivorous and may be very abundant after hatching. Although a cohort of juveniles may be dramatically reduced owing to intense, continuous predation by adult piscivores, their effect as predators of zooplankton may be intense for very short periods. The prospect for a pulse of zooplanktivory followed by a pulse of piscivory heightened our interest in providing quantitative measures of intensity and duration of such short-term dynamics in predator–prey interactions revolving around fishes.
Habitat heterogeneity and habitat selection also influence predator–prey interactions (Werner & Gilliam, 1984). The relatively simple habitats in our study lakes provide only a modest amount of refuge where prey fishes may escape piscivores. Lack of refugia in Peter Lake explains the quick disappearance of the minnows introduced in 1985 and the rapid decline of rainbow trout in 1989 (Chapter 4).
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- Information
- The Trophic Cascade in Lakes , pp. 85 - 102Publisher: Cambridge University PressPrint publication year: 1993
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