HR: 09:45h
AN: H11F-08    [Abstracts]
TI: Hydrologic Alteration and Response of Ecosystem Functions to River Restoration
AU: * Orr, C H
EM: csorr@wisc.edu
AF: UNC-Chapel Hill, Carolina Environmental Program 100 Miller Hall , Chapel Hill, NC 27599-1105 United States
AU: Stanley, E H
EM: ehstanley@wisc.edu
AF: UW-Madison, Center for Limnology 680 N. Park Street, Madison, WI 53706 United States
AB: Stream ecology theory suggests that physical and hydrologic setting is often a dominant determinant of ecosystem structure in fluvial systems. Restorationist practitioners may work under the assumption that if the hydrologic parameters that control biological processes are restored, biotic components of interest should be restored as well. This method is sometimes called passive habitat restoration, or an eco-hydromorphic approach. An alternate to this hypothesis is that biological recovery is constrained by a number of other limitations such as distance to a source population, site history, and presence of invasive species. In this scenario, systems will not be restored by hydrologic alterations alone. To address the influence physical setting has on ecological process, we measured three specific ecological responses of streams to hydrologic manipulations separate restoration projects in Central Wisconsin. The projects shared the common trait of being primarily hydrologic alterations. We measured phosphorus retention capacity in a second-order stream before and after a pair of small dam removals, denitrification rates following the reflooding of a leveed floodplain and an approximately 50-year time series of vegetation recolonization on exposed mud flats following dam removal. In each case the measured responses showed unexpectedly large variability and there was not close correlation between physical and ecologic parameters. Such high variability in response to alterations also made it difficult to determine if the restorations met their goals. One conclusion of these studies may be that we need to move beyond hydrologic alterations to address additional manipulations to better meet the goals of specific projects.
DE: 0466 Modeling
DE: 0470 Nutrients and nutrient cycling (4845, 4850)
DE: 0481 Restoration
DE: 0744 Rivers (0483, 1856)
SC: Hydrology [H]
MN: Fall Meeting 2005