Nutrient enrichment (eutrophication) is a major theme in freshwater ecology. Some themes come and go, but the inevitable release of phosphorus and nitrogen that ac companies human presence seems to ensure that eutrophication will not soon become an outmoded subject of study. Eutrophication raises issues that range from the pressingly practical problems of phosphorus removal to the very fundamental ecological questions surrounding biological community regulation by resource supply. Although it is possible to take a reductionist approach to some aspects of eutrophication, the study of eutro phication is fundamentally a branch of ecosystem ecology. To understand eutrophication in a given setting, one is inevitably forced to consider physical, chemical, and biological phenomena together. Thus while eutrophication is the focus of our study of Lake Dillon, we have assumed that a broad base of lirnnological information is a prerequisite foundation. Eutrophication of a lake can be studied strictly from a lirnnological perspective. If so, the nutrient income of the lake is quantified but the sources are combined within a black box whose only important feature is total loading. It is also possible, however, to treat the watershed and lake as equally important components of a hybrid system. In this case the nutrient sources must be dissected and their variability and dependence on key factors such as runoff must be quantified."

This book is based on the premise that the study of ecological communities should be a composite analysis of system properties (community structure, community energetics) and population properties (life history patterns, adaptive strategies) backed by a thorough understanding of the physical chemical environment. Too frequently community ecology takes a much narrower focus. This may partly be the result of perceived antagonisms between schools of thought in ecology. Despite their rather separate origins, the multiple theoretical and methodological tools that now exist must be applied synthetically to real communities if the progress of the past two decades is to continue into the next two. This book has a case history format, which increases the opportunity for detailed analysis, although I have attempted to maintain the general per spective of a community ecologist and to draw extensively from the literature whenever it seems profitable to do so. The case history data are for Lake Lanao, a large tropical lake. The main zooplankton data base used in the analysis is entirely original and unpublished, although the detailed support ing data on the physical-chemical environment and the phytoplankton com munity have been presented in numerous journal articles and are thus abstracted or used selectively to meet the needs of zooplankton community analysis."