The Balance of Nature?: Ecological Issues in the Conservation of Species and Communities

by Stuart L. Pimm

Overview

Ecologists, although they acknowledge the problems involved, generally conduct their research on too few species, in too small an area, over too short a period of time. In The Balance of Nature?, a work sure to stir controversy, the distinguished theoretical ecologist Stuart L. Pimm argues that ecology therefore fails in many ways to address the enormous ecological problems now facing our planet.

Ecologists describing phenomena on larger scales often use terms like "stability," "balance of nature," and "fragility," and Pimm begins by considering the various specific meanings of these terms. He addresses five kinds of ecological stability—stability in the strict sense, resilience, variability, persistence, and resistance—and shows how they provide ways of comparing natural populations and communities as well as theories about them. Each type of stability depends on characteristics of the species studied and also on the structure of the food web in which the species is embedded and the physical features of the environment.

The Balance of Nature? provides theoretical ecology with a rich array of questions—questions that also underpin pressing problems in practical conservation biology. Pimm calls for nothing less than new approaches to ecology and a new alliance between theoretical and empirical studies.

Product Details

ISBN-13:	9780226668307
Publisher:	University of Chicago Press
Publication date:	02/01/1992
Edition description:	1
Pages:	448
Product dimensions:	6.00(w) x 9.00(h) x 1.30(d)

About the Author

Stuart L. Pimm is the Doris Duke Professor of Conservation Ecology at Duke University. He is the author of many books, including The World According to Pimm: A Scientist Audits the Earth.

Table of Contents

Preface
1. Why "The Balance of Nature"?
What Ecology Is About and What Ecologists Study
The Problems of Scaling Up
What Is the "Balance of Nature"?
Beginnings: Elton and MacArthur
The Last of the Old Meetings
A Theoretical Basis
Heresies
Are Theoretical and Empirical Studies Incompatible?
How This Book Is Organized
2. Resilience
What Is It and How Do We Measure It?
Resilience and the Life-History Characteristics of Individual Species
Food-Web Effects on Resilience
Ecosystem Effects on Resilience
Summary and Conclusions
Appendix
A Note On Temporal Variability
3. Temporal Variability and the Individual Species
Introduction
Body Size and Resistance
Longevity
Resilience and Temporal Variability: Models
Resilience and Temporal Variability: Empirical Studies
Other Factors
Summary and Conclusions
Appendix: The Measurement of Population Variability
4. The Effects of Food-Web Structure
The Ideas of MacArthur and Watt
Temporal Variability and the Diversity of Prey
Temporal Variability and the Diversity of Predators
Abundance: The Relative Contributions of Predator and Prey Diversity
Summary and Conclusions
5. The Variability of the Environment
Environmental Variability Across Space
Environmental Change Over Time
Summary and Conclusions
6. Nonlinear Dynamics, Strange Attractors, and Chaos
The Complexity of Population Change
Where to Look for the Beast
What to Expect: A Bestiary
Meanwhile, in the Real World . . .
Summary and Conclusions
7. Extinctions
From Population Variability to Community Persistence
The Effect of Population Size on Extinction
The Effects of Individual Longevity and Population Resilience
Temporal Variability in Density
The Effects of Spatial and Demographic Structure
Changes in Reproductive Rate at Low Density
Feedback Cycles
Summary and Conclusions
A Note on Persistence
8. Species Differences and Community Structure as Explanations of Why Introductions Fail
The Effects of Individual Adaptations
The Role of Population Parameters
Community Structure and Species Assembly
Summary
9. Patterns in Species Composition
Alternatives
"Competition and the Structure of Ecological Communities"
Rejecting Competition as an Explanation
The Debate Continues
Patterns as Hypotheses: A Catalog
Experiments in Persistence: Introduced Species
Persistence and Predation
Summary
10. Food-Web Structure and Community Persistence
Does Pattern Indicate Persistence?
Food-Chain Lengths
Feeding on More than One Trophic Level
Compartments
Predator-Prey Ratios
Niche Geometry
Cohen's Cascade Model
Summary
11. Community Assembly; Or, Why Are There So Many Kinds of Communities?
Assembly and Persistence
Models of Community Assembly
Implications: Possible Topologies for Community Assembly
Multispecies Simulations
Empirical Studies
Summary and Conclusions
A Note on Resistance
12. Small-Scale Experimental Removals of Species
Do Species Removals Have Effects?
Four Hypotheses as to which Species can be Removed
Looking Upward: Resistance to Changes in Lower Trophic Levels
Summary
13. Food Webs and Resistance
A Food-Web Theory
Indirect Effects in Removal Experiments
Uncertainty in Removal Experiments
The Time Scale of Removal Experiments
Summary
14. Changes in Total Density and Species Composition
Resistance at the Community Level
A Theory for Changes in Species Composition
A Theory for Changes in Total Density
Testing the Theories

Summary

15. The Consequences of Introductions and Extinctions
Resistance on a Large Scale
Do Extinctions and Introductions Cause Further Changes in Species Composition?
Theories of Resistance: Vacant Niches
The Food-Web Theory of Resistance: Its Relevance To Species Introductions and Secondary Extinctions
The Role of History
A Comment about Habiat Islands
Summary
16. Multispecies Models and Their Limitations
Recipes: Getting Community Dynamics from Food-Web Diagrams
17. Conclusions and Caveats
Resilience
Variability
Extinction
Persistence
Resistance
The Difficulties: The Inevitable Approaches to Long-Term, Large-Scale, and Hence Multispecies Studies
Literature Cited
Species Index
Subject Index