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Floodplain Management Session 10 Biology Biological Landscape Prepared by Susan Bolton, PhD, PE. Session 10: Biological Landscape: Its impact on the floodplain and floodplain management. Objectives: 10.1 Explain the importance river systems and their connectivity to oceans
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Floodplain Management Session 10BiologyBiological Landscape Prepared by Susan Bolton, PhD, PE
Session 10: Biological Landscape: Its impact on the floodplain and floodplain management Objectives: 10.1 Explain the importance river systems and their connectivity to oceans 10.2 Describe the 4 dimensions of river ecosystems 10.3 Describe major conceptual theories in stream ecology and how energy flow and nutrient cycling vary among them 10.4 Describe how species are distributed in space and time
Objective 10.1 Explain the importance of freshwater river systems and their connectivity to oceans.
Importance of freshwater streamflow More water moves through ecosystems than any other material Streamflow provides both human and ecosystem services Freshwater and marine ecosystems are interconnected
National water use http://pubs.usgs.gov/circ/2004/circ1268/htdocs/figure01.html
Rivers and Oceans Marine areas with high levels of freshwater inflow usually have significant fisheries e.g., • Mississippi River • Columbia River • Northern Gulf of Alaska
Ecosystem effects of rivers on oceans • Salinity • Organic matter • Nutrients • Sediment • Pollution • Light
Ecosystem effects of rivers on oceans • Evidence of increase number of algal blooms and toxic blooms related to river inputs to marine systems • Changes in nutrient ratios can alter community composition • Alterations of streamflow from flood management activities or river restoration may ultimately affect marine ecosystems
Objective 10.2 Describe the 4 dimensions of river ecosystems
Objective 10.3 Describe major conceptual theories in stream ecology and how energy flow and nutrient cycling concepts vary among them
River Continuum Concept • Early attempt to characterize and classify river ecosystem processes • Focuses on longitudinal changes in energy sources and community structure • Largely ignored lateral and vertical connectivity
River Continuum Conceptual Diagram
Flood Pulse Concept • Recognizes lateral connectivity of streams with floodplains and riparian systems • Flood pulses are episodic inundation of land adjacent to rivers - Interconnection of river and floodplain a major driver of energy and nutrient transfer • Water fluctuations also drive successional patterns of vegetation • Flood pulses recharge aquifers • Recognizes that floods are a natural part of dynamic equilibrium in river systems • Highest explanatory power in areas where geomorphology facilitates lateral connectivity
Hyporheic Corridor Concept • Looks at the vertical integration of the streams with surrounding subsurface water • Describes importance of vertical exchange of materials • Look at separately from longer, slower exchanges via ground water - Microbial activity enhanced by frequent exchanges D. Highest explanatory power where geomorphology facilitates vertical and lateral exchange
Serial Discontinuity Concept • Recognizes that streams do not change uniformly in longitudinal direction • Changes in geomorphology and tributary junctions interrupt Continuum Concepts • Dams also create changes in material transport • Has been expanded to include vertical and lateral connectivity • Highest explanatory power below dams
Biodiversity Concept • Attempts to integrate the many scales of process, function, and community structure into on integrative theme • Connectivity of the 3 spatial dimensions changes with water level • Biodiversity is broader than community, links ecology with evolution, genetics and biogeography
Objective 10.4 Describe how species are distributed in space and time
Surface water Subsurface water Riparian system Springs Confined Reaches Unconfined Reaches Streams Lakes Hyporheic Zone Ground Water How species are distributed in space and time -- Environments contributing to riverine biodiversity
Selected Important Habitat Factors • Substrate • Temperature • Oxygen levels • Flow velocity • Food availability • pH • Nutrient and sediment regimes • Organic input and transport
Species Richness Percent of mainstream richness River --------------------Floodplain Edge How species are distributed in space and time 100 0