Biodiversity and Ecosystem Processes in Tropical Forests

Although biologists have directed much attention to estimating the extent and causes of species losses, the consequences for ecosystem functioning have been little studied.
This book examines the impact of biodiversity on ecosystem processes in tropical forests - one of the most species-rich and at the same time most endangered ecosystems on earth. It covers the relationships between biodiversity and primary production, secondary production, biogeochemical cycles, soil processes, plant life forms, responses to disturbance, and resistance to invasion. The analyses focus on the key ecological interfaces where the loss of keystone species is most likely to influence the rate and stability of ecosystem processes.

1 Introduction.- References.- 2 Plant Species Diversity and Ecosystem Functioning in Tropical Forests.- 2.1 Introduction.- 2.2 The Dependence of Ecosystem Processes on Species Diversity.- 2.3 Plant Species Richness in Tropical Forests.- 2.4 The Primary Productivity of Tropical Forests.- 2.5 The Stability of Tropical Forests.- 2.6 Conclusions.- References.- 3 Consumer Diversity and Secondary Production.- 3.1 Introduction.- 3.2 Secondary Production and Biodiversity.- 3.3 Evolutionary Effects of Consumers on Ecosystem Properties.- 3.4 Ecological Effects of Consumers on Ecosystem Properties.- 3.4.1 Influence of Consumers on Plant Productivity.- 3.4.2 Influences of Consumers on Plant Diversity.- 3.5 Conclusion.- References.- 4 Biodiversity and Biogeochemical Cycles.- 4.1 Introduction.- 4.1.1 Definitions and Concepts.- 4.2 Species Richness and Biogeochemical Cycling.- 4.3 Functional Diversity and Biogeochemistry.- 4.3.1 The Atmospheric-Terrestrial Interface.- 4.3.2 The Biotic Interface.- 4.3.3 The Plant-Soil Interface.- 4.3.4 The Terrestrial-Hydrologic Interface.- 4.4 Evidence from Experimental Studies.- 4.4.1 Plantations versus Natural Forests.- 4.4.2 Experimental Manipulation of Species Composition.- 4.5 Conclusions.- References.- 5 Microbial Diversity and Tropical Forest Functioning.- 5.1 Introduction.- 5.2 The Knowledge Base.- 5.3 Food Chains.- 5.4 Pathogens.- 5.4.1 Control of Herbivores by Pathogens.- 5.4.2 Pathogens as a Source of Distribution.- 5.4.3 Effect of Pathogens on Patterns of Tree Dispersion.- 5.5 Microbial Contributions to Global Biogeochemistry.- 5.5.1 Atmospheric CO2.- 5.5.2 Methane.- 5.5.3 Nitrous Oxide.- 5.5.4 Rock Weathering.- 5. 6 Nutrient Cycling.- 5.6.1 Litter Decomposition and Soil Fertility.- 5.6.2 Symbiotic Nitrogen Fixation Associated with Plant Roots.- 5.6.3 Effects of Microbial Epiphylls and Epiphytes on Nutrient Fluxes.- 5.6.4 Mycorrhizae and Nutrient Uptake.- 5.7 Plant Endophytes.- 5.8 Threats to the Microbiota and the Processes They Mediate.- 5.8.1 Effects of Forest Fragmentation on Plant Symbioses.- 5.8.2 Effects of Forest Fragmentation on Cord-Forming Fungi.- 5.8.3 Effects of Acid Precipitation on Ectomycorrhizae.- 5.8.4 Effects of Air Pollution and Climate Change on Epiphyte Nitrogen Fixation.- 5.8.5 Are Decomposers Redundant in a Heterogeneous Environment?.- 5.9 Conclusions.- References.- 6 Plant Life-Forms and Tropical Ecosystem Functioning.- 6.1 Introduction.- 6.1.1 Functional Significance of Life-Forms.- 6.1.2 Assessing the Consequences of Life-Form Diversity.- 6.2 Classification.- 6.2.1 Stature.- 6.2.2 Longevity.- 6.3 Biogeographical Patterns.- 6.4 Environmental Correlates of Life-Form Diversity.- 6.4.1 Rainfall.- 6.4.2 Altitude.- 6.4.3 Soil Fertility.- 6.5 Episodic Impacts on Life-form Diversity.- 6.5.1 Wind.- 6.5.2 Fire.- 6.5.3 Animals.- 6.5.4 Climate change.- 6.6 Life-Forms and Succession.- 6. 7 Implications of Loss of Life-Forms.- 6.8 Conclusions.- References.- 7 Functional Group Diversity and Recovery from Disturbance.- 7.1 Introduction.- 7.2 Functional Groups Affecting Tropical Forest Dynamics.- 7.2.1 Pioneer Herbs and Shrubs.- 7.2.2 Large-Leaved Understory Herbs and Shrubs.- 7.2.3 Small-Leaved Understory Herbs and Shrubs.- 7.2.4 Pioneer Trees.- 7.2.5 Understory Treelets.- 7.2.6 Emergent and Canopy Trees.- 7.2.7 Canopy Palms.- 7.2.8 Canopy Legumes.- 7.2.9 Vines and Lianas.- 7.2.10 Epiphytes.- 7.2.11 Seed Dispersers.- 7.2.12 Herbivorous Insects and Pathogens.- 7.2.13 Decomposers.- 7.2.14 Mycorrhizal Fungi.- 7.2.15 Soil-Churning Animals.- 7.3 Functional Groups and Natural Disturbance Processes in Tropical Moist Forests.- 7.4 Anthropogenic Disturbances to Tropical Forests.- 7.4.1 Functional Groups Affect Successional Patterns.- 7.4.2 Causes of Depauperate Regeneration Pools.- 7.5 Functional Groups in Tropical Dry Forests.- 7.6 Redundancy within Functional Groups.- 7.7 Conclusions.- References.- 8 Species Richness and Resistance to Invasion.- 8.1 Diversity vs. Stability.- 8.2 Global Patterns.- 8.3 Intentional Introductions.- 8.4 Invasions into Undisturbed Tropical Forests.- 8.5 Speculations.- References.- 9 The Role of Biodiversity in Tropical Managed Ecosystems.- 9.1 Introduction.- 9.2 Examples of Tropical Managed Ecosystems.- 9.2.1 Managed Forests.- 9.2.2 Home Gardens.- 9.2.3 Swidden Agriculture.- 9.2.4 Intensive Annual and Perennial Crops.- 9.2.5 Traditional Rice Systems.- 9.3 Plant Diversity and Primary Productivity.- 9.3.1 Comparisons Between Natural and Managed Ecosystems.- 9.3.2 Productivity of Diverse Cropping Systems.- 9.3.3 Stability of Diverse Cropping Systems.- 9.4 Plant Diversity and Primary Consumers.- 9.5 Plant Diversity and Secondary Consumers.- 9.5.1 Ants in Diverse Cropping Systems.- 9.6 Conclusions.- References.- 10 Synthesis.- 10.1 Introduction.- 10.2 Environmental Gradients.- 10.2.1 Moisture.- 10.2.2 Fertility.- 10.2.3 Elevation.- 10.3 Biodiversity and Functioning of Tropical Forests.- 10.4 Energy Flow.- 10.4.1 Carbon Allocation and Consumption.- 10.4.2 Animal-Animal Interactions.- 10.4.3 Detritus-Detritivores.- 10.5 Materials Processing.- 10.5.1 Atmosphere-Organism.- 10.5.2 Biotic Interface.- 10.5.3 Plant-Soil.- 10.5.4 Atmosphere-Soil.- 10.5.5 Soil-Water Table.- 10.6 Functional Properties over Longer Temporal Scales.- 10.6.1 Provision and Maintenance of Structure.- 10.6.2 Resistance to Invasions.- 10.7 Functional Properties Over Larger Spatial Scales.- 10.7.1 Movement of Materials by Physical Agents.- 10.7.2 Movement of Materials and Energy by Animals.- 10.8 Biodiversity and Responses to Disturbances.- 10.9 Research Agenda.- 10.10 Conclusions.- References.- Species Index.- Topical Index.