Unifying Ecohydrology: Techniques for the study of Aquatic Systems
Todd Clason CE 260 - Hydrology 4-29-04
Goals: Define the idea of Ecohydrology Discuss its Application via Case Studies
Ecohydrology is as yet Poorly Defined in the literature. Provisional Definition: Ecohydrology: the effective combination of principals and methodologies from the fields of ecology and hydrology towards the understanding of aquatic systems. By definition, then, the field should be interdisciplinary.
What do searches for ecology and hydrology turn up? Case Study #1
Biggs, B.J.F, Tuchman, N., Lowe, R. and R. Stevenson, 1999. Resource Stress Alters Hydrological Disturbance Effects in a Stream Periphyton Community. Oikos 85(1): 95-108.
DIATOMS! Periphyton: Microalgae growing on plants. Epilithon: Microalgae growing on rocks. Epipelon: Microalgae on the sediment surface.
Authors tested periphyton resistance and resilience under variable light and nutrient regimes. Used an artificial stream system with natural river water, artificial substrates, and stream "troughs," -- rain gutters.
Interesting results -- but no quantitative measure of disturbance. They need a hydrologist!
Case Study #2
Tillman, D.C., A. Moerke, Ziehl, C., and G. Lamberti, 2003. Subsurface Hydrology and Degree of Burial Affect Mass Loss and Invertebrate Colonisation of Leaves in a Woodland Stream. Freshwater Biology 48(1): 98-107.
Authors tested leaf pack breakdown in upwelling and downwelling zones in a stream system. Ecological implications of POC (particulate organic carbon) processing, with respect to local VHG (vertical hydraulic gradient). VHG Measured with minipiezometers.
Results show increased DOC processing in downwelling zones and taxa-specific hydrologic responses. A good illustration of effective combination of hydrologic techniques to answer ecological questions.
Case Study #3
Thomas, S.A., Newbold, J., Monaghan, M., Minshall, G., Georgian, T. and C. Cushing, 2001. The Influence of Particle Size on Seston Deposition in Streams. Limnology and Oceanography 46(6): 1415-1424.
Authors interested in the relationship between dep -field deposition velocity, and fall -- quiescent water fall velocity and its implication for particle transport. Measured h, water depth; u, water velocity; A, cross-sectional area;
Q, discharge; Qw, unit width discharge; S, channel slope; U*, shear velocity; , shear stress; , transient storage coefficient of exchange; As, cross-sectional area of the transient storage zone; w, mass transfer coefficient of water; and Sw uptake length of the water -- And used a di...