Overview -- Evaluation Of The Use Of Community Similarity Techniques As -- Applied To Phytoplankton Communities / D. C. Reinke -- Some Methods For Measuring Effects Of Toxicants On Laboratory And Field-Colonized Estuarine Benthic Communities / M. E. Tagatz -- Comparison Of Estimates Of Hazard Derived At Three Levels Of Complexity / B. R. Niederlehner, J. R. Pratt, A. L. Buikema, Jr., And J. Cairns, Jr. -- Community-Level Effects Of Coyote Population Reduction / R. H. Schmidt -- The Sea Urchin: Bioassay For The Assessment Of Damage From Environmental Contaminants-A. Pagano, M. Cipollaro, G. Corsale, A. Esposito, E. Ragucci, G. G. Giordano, And N. M. Trieff -- Preliminary Results Of Interlaboratory Testing Of A Standardized Aquatic Microcosm / F. B. Taub, A. C. Kindig, And L. L. Conquest -- A Microcosm Procedure For Determining Safe Levels Of Chemical Exposure In Shallow-Water Communities / J. M. Giddings -- A Comparison Of Mixed Flask Culture And Standardized Laboratory Model Ecosystems For Toxicity Testing / L. J. Shannon, M. C. Harrass, J. D. Yount, And C. T. Walbridge -- Evaluation Of Simple Generic Aquatic Ecosystem Tests To Screen The Ecological Impacts Of Pesticides / P. J. Sheehan, R. P. Axler, And R. C. Newhook -- Population And Guild Analysis For Interpretation Of Heavy Metal Pollution In Streams - R. C. Petersen, Jr. -- Impact Of Drilling Fluids On Seagrasses: An Experimental Community Approach / R. D. Morton, T. W. Duke, J. M. Macauley, J. R. Clark, W. A. Price, S. J. Hendricks, -- S. L. Owsley-Montgomery, And G. R. Plaia -- A Simple In-Stream Test Of Laboratory Findings That NTA Protects Fish And Invertebrates Against Copper And Zinc / J. B. Sprague -- Effect Of 3-Trifluoromethyl-4-Nitrophenol On The Structure And Function Of Protozoan Communities Established On Artificial Substrates / P. V. Mccormick, J. R. Pratt, And J. Cairns, Jr. -- Structural And Functional Response Of Natural Phytoplankton And Periphyton Communities To A Cationic Surfactant With Considerations On Environmental Fate / M. A. Lewis, M. J. Taylor, And R. J. Larson -- Use Of Limnocorrals In Evaluating The Effects Of Pesticides On Zooplankton Communities / N. K. Kaushik, K. R. Solomon, G. L. Stephenson, And K. E. Day -- Zooplankton Community Responses To Synthetic Oil Exposure - L. A. Hook , P. J. Franco, And J. M. Giddings -- Production Of Coexisting Juvenile Coho Salmon And Steelhead Trout In Heated Model Stream Communities / R. M. Hughes And G. E. Davis. Although community level toxicity testing is now being used for practical purposes, it is not the intent of this book to espouse the use of community level testing in all situations or to replace single-species tests that are the best source of information on growth, reproductive success, behavior, and a variety of other end points. On the other hand, since field validation of laboratory predictions is becoming increasingly important and since community level testing offers the possibility of validation by using more comparable or identical end points in complex natural systems, which is not possible for single-species tests, it is now worthy of attention by ASTM members.