1 Floodplain Management Session 10 Biology Biological Landscape Prepared by Susan Bolton, PhD, PE
2 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 10.4Describe how species are distributed in space and time
3 Objective 10.1 Explain the importance of freshwater river systems and their connectivity to oceans.
4 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
5 National water use
6 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
7 Ecosystem effects of rivers on oceans Salinity Organic matter Nutrients Sediment Pollution Light
8 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
9 Objective 10.2 Describe the 4 dimensions of river ecosystems
10 Four dimensions of river ecosystems
11 Objective 10.3 Describe major conceptual theories in stream ecology and how energy flow and nutrient cycling concepts vary among them
12 River Continuum Concept A.Early attempt to characterize and classify river ecosystem processes B.Focuses on longitudinal changes in energy sources and community structure C.Largely ignored lateral and vertical connectivity
13 River Continuum Conceptual Diagram
14 Flood Pulse Concept A.Recognizes lateral connectivity of streams with floodplains and riparian systems B.Flood pulses are episodic inundation of land adjacent to rivers - Interconnection of river and floodplain a major driver of energy and nutrient transfer C.Water fluctuations also drive successional patterns of vegetation D.Flood pulses recharge aquifers E.Recognizes that floods are a natural part of dynamic equilibrium in river systems F.Highest explanatory power in areas where geomorphology facilitates lateral connectivity
15 Hyporheic Corridor Concept A.Looks at the vertical integration of the streams with surrounding subsurface water B.Describes importance of vertical exchange of materials C.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
16 Serial Discontinuity Concept A.Recognizes that streams do not change uniformly in longitudinal direction B.Changes in geomorphology and tributary junctions interrupt Continuum Concepts C.Dams also create changes in material transport D.Has been expanded to include vertical and lateral connectivity E.Highest explanatory power below dams
17 Biodiversity Concept A.Attempts to integrate the many scales of process, function, and community structure into on integrative theme B.Connectivity of the 3 spatial dimensions changes with water level C.Biodiversity is broader than community, links ecology with evolution, genetics and biogeography
18 Objective 10.4 Describe how species are distributed in space and time
19 How species are distributed in space and time -- Environments contributing to riverine biodiversity Surface waterSubsurface waterRiparian system Streams Springs Lakes Hyporheic Zone Ground Water Confined Reaches Unconfined Reaches
20 Selected Important Habitat Factors Substrate Temperature Oxygen levels Flow velocity Food availability pH Nutrient and sediment regimes Organic input and transport
21 How species are distributed in space and time River Floodplain Edge Species Richness Percent of mainstream richness 0 100