# Food Webs (MPB-50)

KEVIN S. MCCANN
Pages: 250
https://www.jstor.org/stable/j.ctt7rr0s

1. Front Matter
(pp. i-vi)
(pp. vii-x)
3. Preface
(pp. xi-xii)
4. ### Part 1 THE PROBLEM AND THE APPROACH

• CHAPTER ONE The Balance of Nature: What Is It and Why Care?
(pp. 3-19)

Each spring as the sun begins to strengthen again, I walk the trail that surrounds our house. Unfailingly, I am met by the steady green carpet of plants, the chorus of songbirds, the scurrying of squirrels, and the occasional hawk presiding over the forest floor. On any spring night I may find myself awakened by the unmistakable cry of coyotes to find that the night is alive with the peeping and buzzing of frogs and insects. At a very rough observational level, the main groups of players that make up this localized food web (i.e., plants, herbivores, predators) appear to...

• CHAPTER TWO A Primer for Dynamical Systems
(pp. 20-46)

This chapter gives a brief introduction to the branch of mathematics known asdynamical systems. My hope is that even the less mathematically oriented reader will pass through this section in order to facilitate understanding of the theory developed in the rest of the book. This chapter is in no way a comprehensive review of dynamical systems. Rather, it is meant to establish familiar terminology as well as to make the reader comfortable with the broad concepts and approaches behind dynamical systems theory. I will argue that most of the mathematics and their graphical representation can be viewed through the...

• CHAPTER THREE Of Modules, Motifs, and Whole Webs
(pp. 47-50)

Thus far I have motivated the problem that this book will address and laid out a mathematical primer that will aid in understanding of the chapters that follow. In the next section of the book (part 2), I proceed by considering the dynamics of important ecological modules or motifs (e.g., populations, consumer-resource interactions, food chains, omnivory). The focus in part 2, then, is to conceptually distill what aspects of population and food web structure increase oscillatory dynamics and what aspects of population and food web structure mute oscillatory dynamics. Given this, then, in the final section (part 3) I proceed...

5. ### Part 2 FOOD WEB MODULES:: FROM POPULATIONS TO SMALL FOOD WEBS

• CHAPTER FOUR Excitable and Nonexcitable Population Dynamics
(pp. 53-66)

While there has been a tremendous amount of theory developed for single-species population dynamics, in this chapter I choose to explore the dynamics behind basic population models with a singular lens. Specifically, I analyze population level models to highlight the general biological conditions under which population dynamics are stabilized, or destabilized, by increased population growth rates. These general results will be taken from three classes of population models. I will start with the well-known continuous logistic model before introducing the notion of discrete population models (i.e., dynamics that respond with an inherent time lag). Finally, I consider continuous models with...

• CHAPTER FIVE Consumer-Resource Dynamics: Building Consumptive Food Webs
(pp. 67-88)

The consumer-resource interaction is one of the fundamental building blocks of food webs. Consumption interactions shunt energy and nutrients through ecological networks and play a critical role in the functioning of all ecosystems. This chapter is consistent with the last chapter in that the intention is to glean general rules from theory. It is not a comprehensive review of C-R theory, rather I will consider C-R theory within the duality laid out in the previous chapter such that I will ask how C-R systems that are nonexcitable and excitable respond to changes in interaction strength. For an excellent, thorough account...

• CHAPTER SIX Lagged Consumer-Resource Dynamics
(pp. 89-102)

There are a number of reasons why the biology of organisms creates lagged effects on populations dynamics. Because of this, the unstructured continuous consumer-resource model in chapter 5 can be argued to miss some of the important dynamical influences of realistic biological lags. Lags occur, for example, when a population reproduces at regular and synchronized intervals in time. Similarly, organisms are almost always comprised of various life stages that often occupy different habitats and feed on different prey items. This stage structure introduces lags into the dynamics of an adult class, as exemplified when a large cohort of juveniles matures...

• CHAPTER SEVEN Food Chains and Omnivory
(pp. 103-122)

It is a natural progression for ecological theory to move beyond the consumer-resource interaction in order to explore common subsystems of food webs (Holt and Loreau, 2002). In fact, May (1974a), who championed the classic whole food web matrix approach, argued that models of intermediate complexity may be a more direct path to interpreting how food web structure influences population dynamics and stability. The notion of thoroughly exploring subsystems has evidently been around for a while. In this chapter I will begin to consider extensions of C-R theory to include simple but common three-species modules, and in the next chapter...

• CHAPTER EIGHT More Modules
(pp. 123-142)

In a general analysis of networks, Milo et al. (2002) found that food webs had an excess of diamond food web modules with and without intraguild predation (figure 8.1). More recent work on whole food web data has found that these diamond and intraguild predation modules are clearly overrepresented relative to randomly constructed networks (Bascompte and Melian, 2005). As discussed in chapter 7, these whole system results agree even with studies done on strongly interacting subsystems, which also found a preponderance of apparent competition and diamond modules [reviewed in Menge (1995)]. In what follows I will proceed by first investigating...

6. ### Part 3 TOWARD WHOLE SYSTEMS

• CHAPTER NINE Coupling Modules in Space: A Landscape Theory
(pp. 145-169)

There are several possible approaches to addressing food webs at the landscape scale. The approach advanced so far in this book is to build toward whole food webs by understanding the addition of subwebs or modules. A second, more classic approach (discussed in the next chapter) is to study large matrices (i.e., whole communities) as championed by May and others (May, 1974a; Pimm, 1982). Still another strategy—and the one employed in this chapter—is to squint at the food web on the landscape, ignoring the details at first, in order to focus on the large-scale food web architecture. When...

• CHAPTER TEN Classic Food Web Theory
(pp. 170-188)

To this point I have emphasized the study of ecological modules and projected to larger systems by arguing that certain modular architectures recur across spatial scales, allowing us to look at stabilizing features at the landscape scale. This approach skips the myriad detailed interactions that actually exist in real webs. The classic approach, on the other hand, has tended to employn-dimensional matrices that express the interactions among allnspecies of a whole community. This approach has the advantage of encapsulating an enormous amount of community information into a relatively simple matrix. Further, well-developed linear stability techniques can be...

• CHAPTER ELEVEN Adding the Ecosystem
(pp. 189-200)

To this point in the book, I have completely ignored the role of nutrient recycling and decomposition. Nutrient recycling and decomposition form larger-scale feedbacks at the ecosystem scale that may play a significant role in the dynamics and stability of food webs. In this brief chapter, I start to explore this fundamental problem and reconcile previous chapters with some of the pioneering efforts of O’Neill (1976) and DeAngelis (1980, 1992) that appear to counter some of the ideas in food web theory. In what follows, we review some of the existing theory on detritus and food web dynamics. I will...

• CHAPTER TWELVE Food Webs as Complex Adaptive Systems
(pp. 201-218)

In the preceding chapters, I have attempted to weave together a theory from population level dynamics to whole-ecosystem dynamics. The picture that emerges is one in which an interaction or a subsystem, under certain conditions, acts to mute or excite other interactions or subsystems. After theoretically identifying attributes of food web structures that are stabilizing/destabilizing, it becomes critical to empirically identify what happens to food web structure when we cross biologically relevant gradients (e.g., ecosystem size). As an example, I argued that spatially expansive ecosystems may be more stable than highly fragmented ecosystems as higher-order mobile consumers may link strongly...

7. Bibliography
(pp. 219-234)
8. Index
(pp. 235-238)
9. Back Matter
(pp. 239-241)