Download Balance of Nature?

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Balance of Nature?
Stuart L. Pimm
Technisehe Unive^Hat Darmstadt
FAC:IH;:RE;CH 10 — BIOL
The University of Chicago Press
Chicago and London
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Contents
Preface / xi
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1. WHY "THE BALANCE OF NATURE"?
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What Ecology Is About and What Ecologists Study / 1
The Problems of Scaling Up / 3
What Is the "Balance of Nature"? / 4
Beginnings: Elton and MacArthur / 6
The Last of the Old Meetings / 8
A Theoretical Basis / 9
Heresies / 12
Are Theoretical and Empirical Studies Incompatible? / 13
How This Book Is Organized / 15
2. RESILIENCE
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18
What Is It and How Do We Measure It? / 18
Resilience and the Life-History Characteristics of
Individual Species / 21
Food-Web Effects on Resilience / 26
Ecosystem Effects on Resilience / 30
Summary and Conclusions / 32
Appendix / 33
A Note On Temporal Variability
35
3. TEMPORAL VARIABILITY AND THE INDIVIDUAL SPECIES
39
Introduction / 39
Body Size and Resistance / 40
Longevity / 43
Resilience and Temporal Variability: Models / 44
Resilience and Temporal Variability: Empirical Studies / 47
Other Factors / 53
Summary and Conclusions / 54
Appendix: The Measurement of Population Variability / 54
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CONTENTS
4. THE EFFECTS OF FOOD-WEB STRUCTURE '
59
The Ideas of MacArthur and Watt / 59
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Temporal Variability and the Diversity of Prey / 63
Temporal Variability and the Diversity of Predators / 71
Abundance: The Relative Contributions of Predator and Prey
Diversity / 78
Summary and Conclusions / 80
5. THE VARIABILITY OF THE ENVIRONMENT
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83
Environmental Variability Across Space / 83
Environmental Change Over Time / 87
Summary and Conclusions / 97
6. NONLINEAR DYNAMICS, STRANGE ATTRACTORS, AND CHAOS
99
The Complexity of Population Change / 99
Where to Look for the Beast / 101
What to Expect: A Bestiary / 107
Meanwhile, in the Real World . . . / 115
Summary and Conclusions / 131
7. EXTINCTIONS
135
From Population Variability to Community Persistence / 135
The Effect of Population Size on Extinction / 135
The Effects of Individual Longevity and Population
Resilience / 144
Temporal Variability in Density / 149
The Effects of Spatial and Demographic Structure / 151
Changes in Reproductive Rate at Low Density / 156
Feedback Cycles / 162
, Summary and Conclusions / 163^
A Note on Persistence
169
8. SPECIES DIFFERENCES AND COMMUNITY STRUCTURE AS
EXPLANATIONS OF WHY INTRODUCTIONS FAIL
The Effects of Individual Adaptations / 173
The Role of Population Parameters / 175
Community Structure and Species Assembly / 181
Summary / 187
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Contents
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9. PATTERNS IN SPECIES COMPOSITION
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189
Alternatives / 189
"Competition and the Structure of Ecological
Communities" / 191
Rejecting Competition as an Explanation / 193
The Debate Continues / 195
Patterns as Hypotheses: A Catalog / 198
Experiments in Persistence: Introduced Species / 207
Persistence and Predation / 217
Summary / 220
10. FOOD-WEB STRUCTURE AND COMMUNITY
PERSISTENCE
222
Does Pattern Indicate Persistence? / 222
Food-Chain Lengths / 223
Feeding on More than One Trophic Level / 225
Compartments / 227
Predator-Prey Ratios"/ 229
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Niche Geometry / 232
Cohen's Cascade Model / 242
Summary / 243
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11. COMMUNITY ASSEMBLY; OR, WHY ARE THERE SO
MANY KINDS OF COMMUNITIES?
245
Assembly and Persistence / 245
Models of Community Assembly / 245
Implications: Possible Topologies for Community
Assembly / 249
Multispecies Simulations / 256
Empirical Studies / 258
Summary and Conclusions / 268 ^
A Note on Resistance
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271
12. SMALL-SCALE EXPERIMENTAL REMOVALS OF SPECIES
Do Species Removals Have Effects? / 277
Four Hypotheses as to which Species can be Removed / 281
Looking Upward: Resistance to Changes in Lower
Trophic Levels / 289
Summary / 292
277
viii
CONTENTS
13. FOOD WEBS AND RESISTANCE
294
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A Food-Web Theory / 294
Indirect Effects in Removal Experiments / 301
Uncertainty in Removal Experiments / 303
The Time Scale of Removal Experiments / 306
Summary / 312 x
14. CHANGES IN TOTAL DENSITY AND SPECIES COMPOSITION
315
Resistance at the Community Level / 315
A Theory for Changes in, Species Composition / 315
A Theory for Changes in Total Density / 321
Testing the Theories / 328
Summary / 333
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15. T H E CONSEQUENCES OF INTRODUCTIONS AND EXTINCTIONS
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Resistance on a Large Scale / 334
Do Extinctions and Introductions Cause Further Changes in
Species Composition? / 335
Theories of Resistance: Vacant Niches / 344
The Food-Web Theory of Resistance: Its Relevance To Species
Introductions and Secondary Extinctions / 346
The Role of History / 353
A Comment about Habitat Islands / 355
Summary / 356
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16. MULTISPECIES M O D E L S AND T H E I R LIMITATIONS
357
Recipes: Getting Community Dynamics from Food-Web
Diagrams / 361
17. CONCLUSIONS AND CAVEATS
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Resilience/371
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Persistence / 378
Variability / 372
~ Resistance / 382
Extinction / 376
The Difficulties: The Inevitable Approaches to Long-Term,
Large-Scale, and Hence Multispecies Studies / 387
Literature Cited / 391
Species Index / 419
Subject Index / 426
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