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Great Ideas in Riverine Ecology. Linear to Landscapes FISH 7380; Dr. E. Irwin. Systems created by water running downhill depend on:. Geology and climate (present and historical). 1) stream classification 2) longitudinal processes. 3) Riparian-river interactions. Land use.
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Great Ideas in Riverine Ecology Linear to Landscapes FISH 7380; Dr. E. Irwin
Systems created by water running downhill depend on: Geology and climate (present and historical) 1) stream classification 2) longitudinal processes 3) Riparian-river interactions Land use River Morphology Hydrology Sediment transport Nutrient/elemental availability Basin flora and fauna Terrestrial communities biota heterotrophy Carbon/solar input Trophic structure Habitat structure Patterns of flows = community function 4) spiraling and retention 5) connectedness 6) biotic/abiotic controls Human interference
Classification • Streams can be classified • Allows managers and scientists to organize river systems • Conceptual and regional approaches • Climate and geology, but vegetation important also • NA-Ecosystem approach (broad scale) • Climate, physiography and vegetation
Hierarchical classification • Spatially nested levels of resolution • Problem—relatively distinct boundaries
Stream Order • Strahler (1952) and modified by Horton (1945) • Variation from headwaters to mouth • Ordering gives a measure of position • Others-link magnitude, d-link
River Continuum Concept • Downstream transfers of energy and matter • Invertebrate functional groups • US—DS in lowland rivers=lateral exchanges and vertical fluxes
River-Riparian Interactions • Allochtonous inputs, LWD • Flood-pulse concept • Annual floods drive organic matter and nutrient input in large floodplain rivers.
Abiotic and Biotic Control • Disturbance • Other abiotic controls • Biotic? • Limiting resources
Disturbance-structures stream communities • High/low flows • Especially in headwaters
Pressure Points • Interference: how management can mess things up. • Discontinuity- • Serial • Faunal