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This chapter examines the influence of biological lags on consumer–resource dynamics, with particular emphasis on how consumer–resource cycles, or the lack thereof, interact with population level dynamical phenomena. It first considers discrete consumer–resource interactions before discussing the dynamics of stage-structured consumer–resource interactions. It then explains how stage structure promotes the possibility of alternative stable states and changes consumer–resource interaction strength. It also shows how a change in population structure affects food web interactions and/or the strengths of food webs. Finally, it reviews empirical results that show how stage structure and food web interaction influence ecological stability. The chapter argues that weak and inherently stable consumer–resource interactions can mute a potentially unstable population level phenomenon, and that a dynamically decoupled stable stage class can strongly stabilize other stages and the consumer–resource interaction.

This chapter focuses on consumer-resource dynamics in systems where consumers of different sizes compete for a shared resource. It considers the implications of three important aspects of consumer life history: the explicit handling of a juvenile period leading to a delay between the time when an individual is born to when it starts to reproduce; the rate by which individual ecological processes scale with body size; and whether the rate by which the individual grows is dependent on food density or not. The chapter examines the effects of different resource growth dynamics to illustrate the fundamental differences between population cycles driven by interactions between individuals of different sizes, and classical predator–prey cycles driven by interactions between the consumer and the resource, also referred to as paradox of enrichment cycles. It also discusses experiments with the model organism, the cladoceran zooplankton Daphnia, to elucidate our current understanding of cycles driven by cohort interactions in this organism.

This chapter focuses on a generalization of a classic consumer-resource model with a single population embedded in a community. It develops this physiologically structured consumer-resource model by extending the static model in Chapter 4. The chapter then studies how density dependence emerges in the model, and how it changes the population size spectrum. Finally, the chapter explores how some of the standard fisheries impact assessments from Chapter 5 are changed when density dependence is in the form of competition or cannibalism. Specifically, it shows how the appearance of late-life density dependence rocks one of the cornerstones of contemporary fisheries management: that we should fish only the largest fish. In some cases, it turns out that yield is instead maximized by fishing juveniles.