River Ecosystem

River Ecosystem

The ecosystem of a river is the river viewed as a system operating in its natural environment, and includes biotic (living) interactions amongst plants, animals and micro-organisms, as well as abiotic (nonliving) physical and chemical interactions.

River ecosystems are prime examples of lotic ecosystems. Lotic refers to flowing water, from the Latin lotus, washed. Lotic waters range from springs only a few centimeters wide to major rivers kilometers in width. Much of this article applies to lotic ecosystems in general, including related lotic systems such as streams and springs. Lotic ecosystems can be contrasted with lentic ecosystems, which involve relatively still terrestrial waters such as lakes and ponds. Together, these two fields form the more general study area of freshwater or aquatic ecology.

The following unifying characteristics make the ecology of running waters unique from that of other aquatic habitats.

• Flow is unidirectional.
• There is a state of continuous physical change.
• There is a high degree of spatial and temporal heterogeneity at all scales (microhabitats).
• Variability between lotic systems is quite high.
• The biota is specialized to live with flow conditions.