Section A: Ecosystem Function.- 1 Biological Diversity and Terrestrial Ecosystem Biogeochemistry.- 1.1 Introduction.- 1.2 Semantics.- 1.3 Biological Diversity and Biogeochemistry.- 1.3.1 Experimental Tests.- 1.3.2 Biogeographic Patterns.- 1.4 Other Potential Effects of Plant Diversity on Biogeochemistry.- 1.5 Conclusions.- References.- 2 Biodiversity and Ecosystem Function in Agricultural Systems.- 2.1 Introduction.- 2.2 Characteristics of Agricultural Ecosystems.- 2.2.1 Diversity and Complexity.- 2.2.2 Classification in Relation to Diversity and Complexity.- 2.2.3 Sustainability.- 2.3 Productive Attributes of Low Number Multiple Cropping Systems.- 2.4 Biodiversity and the Function of the Decomposer Subsystem.- 2.4.1 Biodiversity in Relation to Function.- 2.4.2 Decomposer Diversity and Function in Agricultural Systems.- 2.4.3 Interactions Between Plants and the Soil Biota.- 2.5 Biodiversity and the Function of the Herbivore Subsystem.- 2.6 Conclusions.- 2.6.1 A Hypothesis of the Importance of Plant Diversity in Ecosystem Regulation.- 2.6.2 The Importance of Increasing Plant Species Number.- 2.6.3 The Importance of Plant Species Composition.- 2.6.4 Assessment of Long-Term Trends.- References.- 3 Biodiversity and Interactions Within Pelagic Nutrient Cycling and Productivity.- 3.1 Introduction: Explanations to the Paradox of the Plankton.- 3.2 Further Determinants of Biodiversity.- 3.2.1 Plasticity and Cell Shape.- 3.2.2 Turbulence.- 3.3 Selection and Succession.- 3.3.1 Descriptive Model of Plankton Succession.- 3.4 Microbial Loop: Structure and Function.- 3.4.1 Structure.- 3.5 Structural Diversity Indices.- 3.6 Ataxonomic Approach to Assess Ecosystem Stability.- 3.7 Conclusions.- References.- Section B: Functional Groups.- 4 Functional Groups of Microorganisms.- 4.1 Introduction.- 4.2 Free-Living Components of the Soil Microbiota.- 4.3 Metabolic Types of Bacteria.- 4.4 The Role of Microorganisms in the Decomposition of Organic Material.- 4.4.1 Cellulose.- 4.4.2 Lignin.- 4.4.3 Proteins, Peptides, and Amino Acids.- 4.4.4 Pectin.- 4.5 The Role of Microorganisms in the Biogeochemical Cycle of Nitrogen.- 4.5.1 Nitrification.- 4.5.2 Denitrification.- 4.5.3 N2 Fixation.- 4.6 The Role of Microorganisms in the Biogeochemical Cycle of Sulfur.- 4.6.1 The Oxidation of Reduced Sulfur Compounds.- 4.6.2 Desulfurication.- 4.7 Conclusions.- References.- 5 Plant Traits and Adaptive Strategies: Their Role in Ecosystem Function.- 5.1 Introduction.- 5.2 Schemes to Classify Plants on the Basis of Their Ecological Traits.- 5.2.1 Single-Character Functional Classification of Vascular Plants.- 5.2.2 Attempts to Classify Species Based on Their Overall Ecological Adaptability.- 5.3 Adaptive Strategies.- 5.3.1 Optimization.- 5.3.2 Plant Adaptive Strategies.- 5.3.3 Why Optimally Criteria Are Not Always Sufficient.- 5.4 Definition of Ecosystem Functional Properties.- 5.5 The Meaning of Adaptive Strategy in a Complex, Nonlinear World.- 5.6 Conclusions: The Importance of Diversity in a Nonequilibrium Situation.- References.- 6 Scaling from Species to Vegetation: The Usefulness of Functional Groups.- 6.1 Introduction: What Are Functional Groups and Why Use Them?.- 6.2 Selecting Functional Groups.- 6.3 Narrow or Wide Grouping: The Dilemma of Experimental Safety and Ecological Applicability.- 6.4 Grouping of Plant Species with Respect to Their Structural, Physiological, and Life Strategy Characteristics.- 6.4.1 Life-Forms and Structures: The Morphotype.- 6.4.2 Dry Matter Partitioning: Investment Type.- 6.4.3 The Physiotype.- 6.4.4 The Physiomorphotype.- 6.4.5 Life Strategies.- 6.5 The Spatial Definition of Functional Groups within Plant Communities.- 6.6 Ecosystems: The Largest Functional Group.- 6.7 Integration of Contrasting Levels of Complexity: A Compromise.- 6.8 A Promising Tool: Using Functional Groups in Controlled Ecosystems.- 6.9 Conclusions.- References.- Section C: Species Interaction.- 7 Evolution of Functional Groups in Basidiomycetes (Fungi).- 7.1 Introduction.- 7.2 What Are Fungi?.- 7.2.1 Yeasts and Dimorphic Fungi.- 7.3 Functional Fungal Groups.- 7.4 Evolution of Fungal Parasites of Plants.- 7.5 Evolution in Diverse Wood-Decaying Fungi.- 7.5.1 Saprobic Fungi.- 7.6 Evolution in Symbiontic Basidiomycetes.- 7.6.1 Basidiolichens.- 7.6.2 Mycorrhizae.- 7.7 Diversity and Coevolutionary Trends in Septobasidiales.- 7.8 Conclusions.- References.- 8 The Role of Parasites in Plant Populations and Communities.- 8.1 Introduction.- 8.2 The Diversity and Specialization of Parasites and Their Effects on the Fitness of the Host Plant.- 8.2.1 Parasitic Plants.- 8.2.2 Fungal and Viral Pathogens.- 8.3 The Hidden Effects of Parasite Attack - Changes in the Genetic Structure of Plant Populations.- 8.4 Parasite Attack as a Determinant of Ecosystem Structure.- 8.4.1 Lessons from Exotic Pathogens and Severely Disturbed Natural Systems.- 8.4.2 Evidence from Natural Parasite-Host Associations.- 8.5 Conclusions.- References.- 9 Plant-Microbe Mutualisms and Community Structure.- 9.1 Introduction.- 9.2 Plant-Microbe Mutualisms in Grassland Communities.- 9.3 Plant-Microbe Mutualisms in Savanna and Tropical Forest Communities.- 9.4 Plant-Microbe Mutualisms in Boreal and Temperate Forest Communities.- 9.5 Plant-Microbe Mutualisms in Heathland and Related Wetland Ecosystems.- 9.6 The Role of Mutualisms in Successional Processes.- 9.7 Conclusions.- References.- 10 The Evolution of Interactions and Diversity in Plant- Insect Systems: The Urophora-Eurytoma Food Web in Galls on Palearctic Cardueae.- 10.1 Introduction.- 10.2 The Urophora Food Web.- 10.2.1 General Ecological Characteristics of the Urophora-Eurytoma System.- 10.2.2 Structure and Evolution of the Urophora Gall.- 10.2.3 The Effect of the Gall Size on the Two Eurytoma spp..- 10.3 Resource Exploitation, Interactions, and Evolution.- 10.3.1 The Evolution of Diversity at the Herbivore Level of Plant-Insect Systems.- 10.3.2 Host Plants as Underexploited Resources.- 10.3.3 Exploitation Strategies in the Urophora-Eurytoma System.- 10.3.4 Interaction Patterns at the Second and Third Trophic Level: Evolutionary Adjustments in Food Webs.- 10.4 Conclusions.- References.- Section D: Community Interactions.- 11 Keystone Species.- 11.1 Introduction.- 11.2 History of the Concept.- 11.3 The Different Kinds of Keystone Species.- 11.3.1 Keystone Predators.- 11.3.2 Keystone Herbivores.- 11.3.3 Keystone Pathogens.- 11.3.4 Keystone Competitors.- 11.3.5 Keystone Mutualists.- 11.3.6 Earth-movers.- 11.3.7 System Processes.- 11.3.8 Abiotic Processes.- 11.3.9 Summary of Types of Keystone Species.- 11.4 Identifying Keystone Species.- 11.4.1 Towards a General Protocol.- 11.5 Which Keystone Species Are Vulnerable?.- 11.6 Conclusions.- References.- 12 Redundancy in Ecosystems.- 12.1 Introduction.- 12.2 Evidence from the Fossil Record.- 12.3 Patterns of Energy Flow, Biomass and the Structure of Food Webs.- 12.3.1 Productivity and Biomass.- 12.3.2 Food Webs.- 12.4 Theoretical Models of Ecosystem Stability and Resilience.- 12.4.1 Species Deletion Stability.- 12.4.2 Possible Modelling Approaches.- 12.5 Observations and Experiments on Real Systems.- 12.5.1 Species Richness and Population Fluctuations.- 12.5.2 Keystone Species.- 12.5.3 Manipulation Experiments: General Considerations.- 12.5.4 Manipulation Experiments: Examples.- 12.6 Conclusions.- References.- 13 How Many Species Are Required for a Functional Ecosystem?.- 13.1 Introduction.- 13.1.1 Ecosystems.- 13.2 Species Diversity and Ecosystem Properties.- 13.2.1 Introduction.- 13.2.2 Species Enumerations and Ecosystem Functions.- 13.2.3 The Inequality of Species in Ecosystem Function.- 13.2.4 Species Diversity and Ecosystem Stability.- 13.2.5 Species Numbers and Dynamics: Year-to-Year Averaging.- 13.2.6 Species Numbers and Dynamics: Species Feedbacks.- 13.3 Species Diversity and Ecosystem Dynamics.- 13.3.1 Introduction.- 13.3.2 Experiments.- 13.3.3 Modelling.- 13.4 Conclusions.- References.- 14 Rare and Common Plants in Ecosystems, with Special Reference to the South-west Australian Flora.- 14.1 Introduction.- 14.2 Species Rareness or Commonness and Niche Specialization in Terms of Habitat and Nutritional Preference.- 14.3 Fire as a Factor in Species Commonness and Rarity.- 14.3.1 Strictly Serotinous Obligate Seeder Shrub or Tree Species.- 14.3.2 Non-Serotinous or Partially Serotinous Obligate Seeder Shrub or Tree Species.- 14.3.3 Obligate Seeder Species with Soil-Based Seed Reserves.- 14.3.4 Resprouter Species of High Recruitment Potential.- 14.3.5 Long-Lived, Clonally Reproducing Resprouter Species of Strictly Limited Recruitment Potential.- 14.3.6 Fire Ephemerals.- 14.3.7 Geophytes.- 14.4 The Significance of Morphological and Physiological Variation to Commonness or Rareness of Species.- 14.5 Evaluation of Commonness and Rareness in Related Taxonomic Groupings.- 14.6 The Importance of Biotic Factors in Species Commonness or Rareness.- 14.7 Genetic Correlates of Commonness and Rarity.- 14.8 Conclusions.- References.- 15 Community Diversity and Succession: The Roles of Competition, Dispersal, and Habitat Modification.- 15.1 Introduction.- 15.2 Succession.- 15.2.1 Environmental Constraints.- 15.2.2 Interspecific Trade-offs.- 15.2.3 Successional Theories.- 15.2.4 Successional Dynamics and the Existing Species Pool.- 15.3 Biotic Diversity.- 15.3.1 Spatial Heterogeneity.- 15.3.2 Local Recruitment Limitation.- 15.3.3 Succession and Biodiversity.- 15.3.4 Constraints, Trade-offs, and the Conservation of Biodiversity.- 15.4 Conclusions.- References.- Section E: Ecosystem Integrity.- 16 Biodiversity and the Balance of Nature.- 16.1 What Biodiversity is Good for.- 16.2 A History of Ecological Stability.- 16.2.1 Controversy.- 16.3 The Stability of Populations.- 16.3.1 Resilience: The Example of Pest Outbreaks.- 16.3.2 Year-to-Year Variability in Densities.- 16.4 The Persistence of Communities.- 16.4.1 Extinction.- 16.4.2 Invasions.- 16.5 Resistance to Change.- 16.6 Conclusions.- References.- 17 Biodiversity and Function of Grazing Ecosystems.- 17.1 Introduction.- 17.1.1 Intellectual Origins.- 17.1.2 Conceptual Development.- 17.1.3 An Individual Remark.- 17.2 Theory and Empiricism.- 17.2.1 Conceptual Definitions.- 17.3 How to Test.- 17.4 Tests.- 17.4.1 Diversity and Productivity.- 17.4.2 Diversity and Stability.- 17.5 Stability of Species Composition to Drought and Grazing: Yellowstone Grazing Ecosystem.- 17.6 Conclusions: Biodiversity and Ecosystem Function.- 17.6.1 Biodiversity, Productivity, and Stability.- 17.6.2 Biodiversity, System Perpetuation, and Global Change.- References.- 18 Resource Supply and Disturbance as Controls over Present and Future Plant Diversity.- 18.1 Introduction.- 18.2 Future Resource and Disturbance Regimes.- 18.3 Plant Genetic Diversity.- 18.3.1 Patterns of Genetic Diversity.- 18.3.2 Land-Use Changes and Habitat Fragmentation.- 18.3.3 Climatic Effects.- 18.3.4 Resource Availability.- 18.4 Plant Species Diversity.- 18.4.1 Regional Patterns.- 18.4.2 Latitudinal Patterns.- 18.4.3 Paleoecological Patterns.- 18.4.4 Future Changes.- 18.5 Diversity of Plant Functional Groups.- 18.5.1 General Considerations.- 18.5.2 Control by Resources and Disturbance.- 18.5.3 Types of Functional Groups.- 18.5.4 Climatic Predictors.- 18.5.5 Future Diversity.- 18.6 Landscape Diversity.- 18.7 Consequences of Changing Biodiversity.- 18.8 Conclusions.- References.- 19 Ecosystem Stability, Competition, and Nutrient Cycling.- 19.1 Introduction.- 19.2 Stability of Model Ecosystems.- 19.3 Competition and the Loss of Diversity.- 19.4 Stabilizing Consequences of Competitive Interactions.- 19.5 Effects of Organisms on Their Physical Environment.- 19.6 Features Affecting Plant Fitness Under Different Nutrient Supply Conditions.- 19.7 Consequences of the Different Effects of Plant Species on the Nutrient Cycle.- 19.8 Conclusions.- References.- 20 Modelling Biodiversity: Latitudinal Gradient of Forest Species Diversity.- 20.1 Introduction.- 20.2 Hypotheses Explaining the Variation of Species Diversity.- 20.2.1 Specialization of Resource Use.- 20.2.2 Mode of Disturbance.- 20.2.3 Smaller Opportunity for Competition.- 20.2.4 Productivity.- 20.2.5 Specific Herbivores and Pathogens.- 20.2.6 Evolutionary/Ecological History.- 20.3 Tree-by-Tree Replacement: Finite Population Models.- 20.3.1 Spatial Scale of Disturbance and Dispersal.- 20.3.2 Inhibited Regeneration.- 20.3.3 Temporal Fluctuation of Regeneration Ability.- 20.4 Species Packing to Temporal Niches: Infinite Population Models.- 20.4.1 Model.- 20.4.2 Species Diversity Versus the Length of the Unfavorable Season.- 20.4.3 Species Diversity Versus Niche Width.- 20.4.4 Phenology of Coexisting Species.- 20.5 Conclusions.- References.- 21 Functional Aspects of Landscape Diversity: A Bavarian Example.- 21.1 Introduction.- 21.2 Geology and Vegetation.- 21.3 Land Use in Northeast Bavaria.- 21.3.1 Hedgerows.- 21.3.2 Grasslands.- 21.3.3 Forests.- 21.4 Conclusions.- References.- Section F: Industrial Analogy and Policy.- 22 Biodiversity Issues in Computing: A Study of Networked Computer Viruses.- 22.1 Introduction.- 22.2 Stable Distributed Computer Systems.- 22.3 Computer Viruses.- 22.3.1 Duff's Virus.- 22.3.2 The Morris Virus.- 22.4 Diversity and the Spread of a Networked Virus.- 22.4.1 A Simple Mathematical Model.- 22.4.2 Functional Diversity.- 22.4.3 Species Diversity.- 22.5 Conclusions.- References.- 23 Biodiversity and Policy Decisions.- 23.1 Introduction.- 23.2 Conserving Biodiversity.- 23.3 Global Climate Change.- 23.4 Ecological Research and Policy Decisions.- 23.5 Providing Policy-Relevant Research Results.- 23.6 Conclusions.- References.- 24 Ecosystem Function of Biodiversity: A Summary.- 24.1 Introduction.- 24.2 What Is an Ecosystem?.- 24.3 The Regulation of Ecosystem Processes.- 24.4 Are There Functional Groups?.- 24.5 Determinants of Species Numbers.- 24.6 Ecosystem Integrity.- 24.7 Effects of Global Change on Land Use and Climate..- 24.8 Conclusions.- References.- Species Index.