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This volume is a result of the summary and synthesis of data collected in the Grassland Biome Program, which is part of the American contribution to the International Biological Program (IBP). The purpose of this volume is to present a summary of quantitative ecological investigations of North American grass lands and to present a set of broad comparisons of their characteristics and functions as well as the results of some models and experiments that lead to practical considerations of the management of grasslands. Synthesis is a continuing activity in science. Early in the Grassland Biome Program there was a synthesis of literature data on grasslands, edited by R. L. Dix and R. G. Beidleman (1969). Results of the first year of field data collection under this program were synthesized in a volume edited by N. R. French (1971). Development of the large-scale model constructed to depict the processes and the dynamics of state variables in grassland ecosystems was presented by Innis (1978). Soon to appear will be two volumes integrating studies of American grasslands with IBP studies in other grasslands of the world (Coupland, in press) and the application of systems analysis to understanding grassland function and utilization (Breymeyer and Van Dyne, in press). The present volume presents current results and comparisons of field investigations and experimental studies that were conducted under this program.
Sommario
Types of Grassland.- Final Year of Grassland Biome Studies.- 1. Grassland Primary Production: North American Grasslands in Perspective.- Grassland.- Method of Analysis.- Results.- North American Grasslands in Perspective.- Summary.- References.- 2. Processes Controlling Blue Grama Production on the Shortgrass Prairie.- Processes Controlling Primary Production.- Simulated Biomass Dynamics.- Summary.- References.- 3. Analysis of the Response of a Grassland Ecosystem to Stress.- and Area Description.- Experiment on Ecosystem Stress.- Results.- Conclusions.- Summary.- References.- 4. Grassland Biomass Trophic Pyramids.- Methods.- Results.- Discussion.- Summary.- References.- 5. Patterns of Consumption in Grasslands.- Methods.- Results.- Summary.- References.- 6. An Ecosystem-Level Trophic-Group Arthropod and Nematode Bioenergetics Model.- The Model.- Summary.- References.- 7. Factors Influencing Input and Output of Nitrogen in Grasslands.- Additions of N to Grassland Ecosystems.- Losses of N from Grassland Ecosystems.- Environmental Factors Controlling Loss of NH3 by Volatilization.- Calculations of Additions and Losses of N from Western Grasslands.- Conclusions.- Summary.- References.- 8. Simulated Impact of Management Practices upon the Tallgrass Prairie.- Simulation of Management Practice.- Summary.- References.- 9. Data-Based, Empirical, Dynamic Matrix Modeling of Rangeland Grazing Systems.- Modeling Systems.- Model Development.- Model Testing.- Model Experimentation and Analyses.- Summary.- References.- 10. Principal Subsystem Interactions in Grasslands.- Producer-Environment Relationships.- Producer Interrelationships.- Consumer-Producer Relationships.- Consumer Relationships.- Trophic Relationships.- Microbial Decomposition.- Conclusions.- Summary.- References.
