The River Continuum Concept

We cover basic concepts and advances in stream ecology related to the River Continuum Concept (RCC). The RCC describes how position in the watershed influences rivers and streams. These influences include materials washing in from the watershed above and those properties dictated by terrestrial habitats that border the rivers or streams in the vicinity. The influences extend from ecosystem properties such as respiration and photosynthesis to animal community composition and function. A single highly influential paper outlined the RCC and many researchers have refined and/or analyzed the concept since then. It forms a focal point and organizing principle of much research on river and stream function as viewed from a landscape perspective. The concept has spurred considerable research and forms the basis for many observed properties of rivers in the real world. Critiques of the concept suggest that the scale of inference is too large and local processes such as flooding or geomorphology may be more important than the overall position in the watershed. Additionally, the original concept was oriented towards streams originating in temperate forested systems, and it misses some key aspects of rivers from other biomes. The RCC is a strong organizing concept for teaching stream ecology and linking ecosystem concepts to organismal biology. It continues to have even broader applicability as scientists tune it to specific biomes and combine it with other conceptual approaches that consider aspects complementary to those in the original publication.