Watersheds are transitional, multi-layered complexes of ecosystems and ecotones that transect many different environments from headwaters to river mouths, uplands to mid channels and surface waters to aquifers. Watersheds are the natural habitat of most people of the world and therefore the ecosystem complex most impacted by human exploitation, ignorance and carelessness. However, all of the active waters of the Earth have cycled though these global flowing water systems many times throughout the eons. We are just beginning to recognize and appreciate the importance of watersheds on such a scale. Forests feed streams.
Streams feed rivers.
Rivers feed the sea. Headwaters are composed of many small, branching streams that form the headwaters, representing most of the total stream length within a watershed. Leaves, fruit, branches and whole trees of stream side forests fall into these headwater streams. Fungi and bacteria grow on the surface of this detritus and begin to break down the complex cellulose molecules of dead plant material. As shredders gnaw through wood and leaf, they create fine particulate organic matter that is filtered from the flowing water by collectors.