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Fluctuations in fish populations in lakes can cascade through food webs to alter nutrient cycling, algal biomass and primary production. Trophic cascades may interact with nutrients and physical factors to explain most of the variance in lake ecosystem process rates. In this 1993 book, a multidisciplinary research team tests this idea by manipulating whole lakes experimentally, and coordinating this with palaeolimnological studies, simulation modelling, and small-scale enclosure experiments. Consequences of predator-prey interactions, behavioural responses of fishes, diel vertical migration of zooplankton, plankton community change, primary production, nutrient cycling and microbial processes are described. Palaeolimnological techniques enable the reconstruction of trophic interactions from past decades. Prospects for analysing the interaction of food web structure and nutrient input in lakes are explored.
Sommario
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 and diel vertical migration of Daphnia; 10. Zooplankton biomass and body size; 11. Phytoplankton community dynamics; 12. Metalimnetic phytoplankton; 13. Primary production and its interactions with nutrients and light transmission; 14. Heterotrophic microbial processes; 15. Annual fossil record of food-web manipulation; 16. Simulation models of the trophic cascade: predictions and evaluations; 17. Synthesis and new directions; Index.
Riassunto
Experimental manipulations of whole lakes are used to test the idea that fluctuations in productivity can be driven by variations in predator populations. This 1993 book shows that population and ecosystem processes can be strongly linked. The study combines population, community and ecosystem ecology.
