Stream Ecology

by

John S. Richardson

• LAST REVIEWED: 28 February 2023
• LAST MODIFIED: 27 October 2016
• DOI: 10.1093/obo/9780199830060-0068

Introduction

Ecology is the scientific study of the interactions between organisms and their environment (including other organisms); therefore, stream ecology encompasses the full field of ecology using flowing waters as the system of study. A stream is the broad term applied to running waters of all sorts; streams may also be named rivers, creeks, brooks, etc., according to the size of the stream. The subdisciplines of stream ecology include all processes from evolutionary ecology to ecosystem and global scales. Stream ecology also includes the study of how energy and nutrients move through flowing, freshwater ecosystems and are captured by organisms directly from the environment (plants) or through their food (animals, fungi, bacteria, and protists). Stream ecologists also study how different organisms interact with each other to understand the interconnections and impacts, such as how the numbers and sizes of each species are influenced by its prey, its competitors and predators, and even diseases. All of this study allows us to predict how changes to the environment or abundances of species may affect the biological diversity, productivity, and stability of freshwater ecosystems. This gives us the ability to manage wisely and to know how to protect these important ecosystems. Particular features of streams create different challenges and solutions for life in a moving environment that give additional insights into ecological processes and their controls. Stream ecology is allied with limnology and is considered a component of limnology by some; however, limnology strictly means the “study of lakes.” Although many of the same ecological research themes are present in lakes and streams, this article distinguishes between these two subdisciplines of freshwater biology and focuses on streams. Some authors will refer to lotic ecology, or lotic ecosystems, in which “lotic” refers to flowing water, in contrast to “lentic,” or still-water ecosystems such as lakes and wetlands. Stream ecology also includes stream biogeochemistry and is linked closely to physical sciences such as hydrology and fluvial geomorphology.

General Overviews

Stream ecology has a variety of themes representing the full spectrum of ecology from individuals (e.g., genetics, behavior, habitat, and feeding) to ecosystems (e.g., nutrient cycling, ecosystem services, conservation, and global change). The importance of water to the human enterprise has placed a large demand on running water ecosystems; therefore, a major emphasis of this article is on applied aspects of stream ecology, with the Applications section providing links to that literature. Streams are also highly dependent on organic matter from terrestrial sources that falls or is washed into streams, making streams a mostly heterotrophic system, meaning that more of the production comes from external sources than from primary production within streams, although this varies with stream size and other features. Benke and Cushing 2005 and Tockner, et al. 2008 provide extensive information about specific rivers in North America and Europe.

• Benke, Arthur C., and Colbert E. Cushing, eds. 2005. Rivers of North America. Boston: Elsevier.

  This book provides a detailed reference to details of streams, primarily large streams, in North America, including human history, hydrology, and biology.

• Tockner, Klement, Urs Uehlinger, and Christopher T. Robinson, eds. 2008. Rivers of Europe. London: Academic Press.

  This book provides details on the larger streams of Europe, including details of geology, hydrology, and biology.