Tuesday, March 9, 2010

Davenport's Greenways Class

Dr. Davenport lectured today on the structure and functions of riparian corridors.

Key ecological functions:
  • helps water quality
  • helps buffer against erosion
  • helps animals
  • stream organisms use organic material ("leaf litter") from riparian vegetation ("downed woody debris") helps add complexity to the stream channel and helps animals like amphibians lay their eggs in eddies and slow moving water away from the "flow".

Two characteristics of riparian ecosystems:
1. laterally flowing water rises and falls during growing season.
2. high degree of connectiedness, e.g., through flooding, or through animals feeding and foraging and carrying with nutriants and waste; energy is carried back and forth.

Might need to know what plants and animals live near a greenway before designing it and what their needs are.

Riparian vegetation reulates factors such as water temperatures.

River Continuum Concept: can have different order streams, going from first to second to third, etc.; faster flowing and less shade; in other places it could have a lot of shade and be very fast flowing if'it's a mountain stream and shade occurs early and late in the day.

1st order is smallest, and might not flow all year; two of the same level combining would make for a larger "higher" level stream.

When designing greenways we need to consider what species would persist, and what kinds of streams would be good for providing the basis of a greenway.

Also need to consider buffer width of greenways. Factors influencing buffer effectivenss include:
  • Invasive Species: can increase errosion due to sparse root network.
  • Sediment removal effectiveness
  • Nutrient and pollutant removal effectiveness
  • Floral and faunal community structure protection
  • Budget to research effectiveness of buffer (includes costs for scientists to go into the field to collect data, then to do the analysis in the lab; compuer analysis and modelling tasks also could be part of the budget.
Expensive to do, but might need to do conduct the studies in order to get funding.

Aha! The need to spend money to get money! Sounds familiar...

More soon y'all! And thanks Dr. Davenport! (They used the rest of the period to go over the midterm and talk about their research projects.)

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