The question "Why are there so many species?" has puzzled ecologist for a long time. Initially, an academic question, it has gained practical interest by the recent awareness of global biodiversity loss. Species diversity in local ecosystems has always been discussed in relation to the problem of competi­ tive exclusion and the apparent contradiction between the competitive exclu­ sion principle and the overwhelming richness of species found in nature. Competition as a mechanism structuring ecological communities has never been uncontroversial. Not only its importance but even its existence have been debated. On the one extreme, some ecologists have taken competi­ tion for granted and have used it as an explanation by default if the distribu­ tion of a species was more restricted than could be explained by physiology and dispersal history. For decades, competition has been a core mechanism behind popular concepts like ecological niche, succession, limiting similarity, and character displacement, among others. For some, competition has almost become synonymous with the Darwinian "struggle for existence", although simple plausibility should tell us that organisms have to struggle against much more than competitors, e.g. predators, parasites, pathogens, and envi­ ronmental harshness.

Inhalt

1 Introduction.- 1.1 The Intellectual Debate Until 1990.- 1.2 Progress During the Last Decade.- 1.3 Consequences for the Structure of the Book.- References.- 2 Competition in Well-Mixed Habitats: From Competitive Exclusion to Competitive Chaos.- 2.1 Introduction.- 2.2 Competition for a Single Abiotic Resource.- 2.2.1 Growth of a Single Species.- 2.2.2 Competitive Interactions.- 2.2.3 Competition for Light.- 2.3 Resource Storage.- 2.3.1 A Competition Model Based on Storage.- 2.3.2 Storage in a Constant Environment.- 2.3.3 Storage in a Variable Environment.- 2.4 Competition for a Single Biotic Resource.- 2.5 Competition for Two Resources.- 2.5.1 Essential vs. Substitutable Resources.- 2.5.2 Abiotic Resources.- 2.5.3 Biotic Resources.- 2.6 Competition for Three Resources.- 2.6.1 Competitive Oscillations.- 2.6.2 Competitive Chaos.- 2.7 Discussion.- References.- 3 Spatial Models of Competition.- 3.1 Introduction.- 3.2 Implicitly Spatial Models.- 3.2.1 Single Species Model.- 3.2.2 Two Species Models.- 3.2.3 Conclusion.- 3.3 Explicitly Spatial Models.- 3.3.1 Interacting Particle Systems.- 3.3.2 Point Process Models.- 3.3.3 Pair Approximation and Moment Methods.- 3.3.4 Reaction-Diffusion Models.- 3.4 Comparing and Connecting Methods.- 3.5 Underlying Spatial Heterogeneity.- 3.5.1 Reaction-Diffusion Models.- 3.5.2 Neighborhood Models.- 3.5.3 Patch Models.- 3.5.4 Conclusion.- 3.6 Competition and Coexistence.- 3.7 Future Directions.- 3.7.1 More Work on Environmental Heterogeneit.- 3.7.2 Combining Population and Ecosystem Perspectives.- 3.7.3 Competition for Light Among Terrestrial Plants.- 3.7.4 Evolution and Community Assembly.- References.- 4 Competition and Coexistence in Plankton Communities.- 4.1 Introduction.- 4.1.1 What Makes Plankton Competition Special?.- 4.1.2 The Chemostat as an Experimental System.- 4.2 Competition Experiments in Laboratory Microcosms.- 4.2.1 Competition Experiments Under Constant Conditions.- 4.2.2 Competition Experiments Under Temporally Variable Conditions.- 4.3 Experiments in Field Mesocosms.- 4.4 Tests of the Intermediate Disturbance Hypothesis by Field Data.- 4.5 Herbivory and Diversity.- 4.6 The Role of Abundance and of Seasonality.- 4.7 Conclusions.- References.- 5 Competition and Coexistence in Mobile Animals.- 5.1 Introduction.- 5.2 Competition Among Mobile Animals.- 5.3 Heterogeneity, Trade-Offs, and Competition.- 5.4 Scale and Heterogeneity.- 5.5 New Challenges.- References.- 6 Competition, Coexistence and Diversity on Rocky Shores.- 6.1 Introduction.- 6.1.1 What Distinguishes Rocky Shores from Other Communities?.- 6.1.2 Evolution of Competition Theory.- 6.2 Disruption of Competitive Exclusion: The Non-Equilibrium View.- 6.2.1 Keystone Predation and Herbivory.- 6.2.2 Strong vs. Weak Interactions.- 6.2.3 The Effects of Physical Disturbance.- 6.3 Coexistence Through Trade-Offs: The Equilibrium View.- 6.3.1 The Resource-Ratio Hypothesis.- 6.3.2 The Competitive Hierarchy Hypothesis.- 6.3.3 Intransitive Competitive Networks.- 6.4 Synthesis: Integrating the Effects of Competition, Consumption and Disturbance.- 6.4.1 Consumer vs. Resource Control of Species Diversity.- 6.4.2 An Integrated Competition Model.- 6.5 Conclusion.- 6.5.1 Unifying Competition Theory.- 6.5.2 Competition, Coexistence and the Human Impact.- References.- 7 Competition and Coexistence in Terrestrial Plants.- 7.1 Introduction.- 7.2 Competition.- 7.2.1 Resource Competition.- 7.2.2 For Which Resources Do Species Compete?.- 7.2.3 Physiological and Morphological Mechanisms of Competition.- 7.2.4 Competition Summary.- 7.3 Coexistence.- 7.3.1 Neutral Theory of Biodiversity.- 7.3.2 Spatial Heterogeneity.- 7.3.3 Competition-Colonization Trade-Off.- 7.3.4 Temporal Variability.- 7.3.5 Additional Trophic Level.- 7.3.6 Multiple Mechanisms of Coexistence and Limits to Diversity.- 7.3.7 Coexistence Summary.- 7.4 Conclusion.- References.- 8 Synthesis: Back to Santa Rosalia, or No Wonder There Are So Many Species.- 8.1 Trade-Offs.- 8.2 Disturbance, Predation and Competition.- 8.3 The Spatial Dimension.- 8.4 Self-Generated Heterogeneity.- 8.5 Exclusive Resources.- 8.6 Slow Exclusion.- 8.7 Equilibrium vs. Non-Equilibrium Concepts.- 8.7.1 The Semantic Problem.- 8.7.2 The Scale Problem.- 8.8 Future Challenges.- References.