An introduction to fluvial ecosystems

This chapter provides an overview of the diversity of rivers and streams, including some of the causes of this diversity, and some of the consequences. The intent is to provide a road map for the individual chapters that follow, rather than define terms and explain principles in detail. By sketching out the broadest patterns of fluvial ecosystems and providing at least a glimpse of the underlying processes, we hope this introduction will serve as a framework for the entire book. Some of these generalizations may later be qualified to recognize their exceptions and limitations. Yet, it is through this effort to elucidate the working principles of fluvial ecosystems and how environmental context governs their expression that river ecologists hope to comprehend the enormous variety of streams and rivers, and provide the needed guidance to ensure their sustained well-being.