1. Figure 20. 1 A walleye (Sander vitreum) consuming shiners (Cyprinidae)
Figure 20.1 A walleye (Sander vitreum) consuming shiners (Cyprinidae). Photograph courtesy: Bill
Lindauer Photography.
Freshwater Ecology: Concepts and Environmental Applications of Limnology © 2019

2. Figure 20.2 A food web of Duffin Creek, Ontario, Canada, in December illustrating the high degree
of omnivory of the aquatic invertebrates. Data from Tavares-Cromar and Williams (1996).
Freshwater Ecology: Concepts and Environmental Applications of Limnology © 2019

3. the lake likely rely on phytoplankton. Data from Fry (1991).
Figure 20.3 Stable isotope signatures of components of the food web in Lookout Creek,
Oregon (A) and Toolik Lake, Alaska (B). Errors plotted as standard error where data were
available. Note that the use of both isotopes allows for clearer separation of the food web
components. The primary consumers in the stream probably rely on periphyton, but those in
the lake likely rely on phytoplankton. Data from Fry (1991).
Freshwater Ecology: Concepts and Environmental Applications of Limnology © 2019

4. Figure 20.4 Daphnia lumholtzi, an invasive species in the central United States with large spines
that protect it from predation (A) and Bythotrephes cederstroemi, the spiny waterflea (B). (A)
Photograph courtesy: K. D. Hambright; (B) photograph courtesy: The National Oceanic and
Atmospheric Administration Great Lakes Environmental Research Laboratory.
Freshwater Ecology: Concepts and Environmental Applications of Limnology © 2019

5. Figure 20.5 Diel vertical migration of young Daphnia longispina in Lake Lucerne. Data from
Worthington (1931).
Freshwater Ecology: Concepts and Environmental Applications of Limnology © 2019

6. encounter rates). Data from Werner and Hall (1974).
Figure 20.6 Selectivity of bluegill (Lepomis macrochirus) on size of prey (Daphnia magna) at two
prey densities. At low densities, all sizes of Daphnia are equally represented in the bluegill guts. At
high densities of prey, the larger zooplankton are preferred (selectivity relative to expected
encounter rates). Data from Werner and Hall (1974).
Freshwater Ecology: Concepts and Environmental Applications of Limnology © 2019

7. assuming constant predator numbers.
Figure 20.7 Holling’s three types of functional response curves and the proportion of prey consumed
assuming constant predator numbers.
Freshwater Ecology: Concepts and Environmental Applications of Limnology © 2019

8. increase (B). Note, not drawn to scale outside of each tropic level.
Figure 20.8 A conceptual diagram of the trophic cascade in the pelagic zone of lakes. When large
piscivores are present, smaller zooplanktivores are uncommon, body size and numbers of zooplankton
increase, and phytoplankton decrease (A), when they are not, phytoplankton numbers
increase (B). Note, not drawn to scale outside of each tropic level.
Freshwater Ecology: Concepts and Environmental Applications of Limnology © 2019

9. Figure 20.9 Effects of biomanipulation on fish, chlorophyll, Daphnia, and macrophyte cover in four
shallow eutrophic lakes in The Netherlands. Year 0 is before biomanipulation. Points are means
from four lakes and error bars equal 1 SD. Data from Meijer et al. (1994).
Freshwater Ecology: Concepts and Environmental Applications of Limnology © 2019

10. Figure Dr. Mary Power.
Freshwater Ecology: Concepts and Environmental Applications of Limnology © 2019

11. amount of biomass at each trophic level. Data from Power (1990).
Figure Summary of effects of enclosure (A) and exclosure (B) on predatory fishes [roach
(Hesperoleucas symmetricus) and steelhead (Oncorhynchus mykiss)], roach and stickleback
(Gasterosteus aculeatus) fry, invertebrate predators (lestid damselflies), midge larvae
(Pseudochironomus richardsoni), and benthic algae (Nostoc and Cladophora). Size of oval represents
amount of biomass at each trophic level. Data from Power (1990).
Freshwater Ecology: Concepts and Environmental Applications of Limnology © 2019