Stream Classification & Abiotic Factors

Watershed A contiguous area that is contained with an elevated ridge such that rainfall within the area flows down and ultimately out through one point (the lowest in elevation).

Lotic Ecosystem Lotic ecosystems are freshwater systems with flowing water. Examples include rivers, streams, creeks, and brooks. Ambiguity of commonly used terminology has led to the “stream orders” system of classification.

Stream Orders 1 st order streams occur where the stream originates 2 nd order streams arise where two 1 st order streams join The order doesn’t change where two streams of different orders come together 3 rd order streams arise where two 2 nd order streams join

Stream Ecology Ecology is the study of the interactions between the non-living (abiotic) and living (biotic) components of an ecosystem, and the interactions between the living components with each other. What are important abiotic factors that help to distinguish the low order, headwater streams, from the high order, riverine habitat?

Headwaters Lower order streams compose the headwaters. Important abiotic factors include elevation, water velocity, temperature, dissolved oxygen, and turbidity, available sunlight, substrate size, and stream width and depth.

Riverine Habitat Higher order streams compose the riverine habitat Important abiotic factors are the same as those found in the headwater streams but are generally opposite in nature

Lotic to Lentic Ecosystems