HR: 1330h
AN: NB33G-13    [Abstracts]
TI: A Test of the Serial Discontinuity Concept Using Pre- and Post-Impoundment Data: do Ecosystems Recover?
AU: * Powell, H
EM: hmpowell@ucalgary.ca
AF: University of Calgary, Department of Biological Sciences, Calgary, AB T2N 1N4 Canada
AU: Jackson, L
EM: ljackson@ucalgary.ca
AF: University of Calgary, Department of Biological Sciences, Calgary, AB T2N 1N4 Canada
AU: Culp, J
EM: Joseph.Culp@ec.gc.ca
AF: University of New Brunswick, Department of Biology, Fredericton, NB E3B 6E1 Canada
AB: Many rivers are influenced by human-made impoundments that alter natural habitat. Changes in habitat hold potential consequences for biotic community structure and ecosystem function. The serial discontinuity concept (SDC), however, predicts that riverine process and function will recover downstream from an impoundment via tributary inputs. Unfortunately, rivers rarely exist in the context assumed by the SDC. Often, watersheds include multiple impoundments and other flow-altering structures. We present preliminary data and future research goals to investigate the changes in riverine habitat and benthic community structure before and after impoundment over 400 km of the Oldman River, southern Alberta, Canada. Habitat characteristics and benthic invertebrate abundance and community structure prior to dam construction were tested against post-impoundment data. Results indicate that 15 years after impoundment, flow and sediment regimes have not recovered. There is a significant decline in discharge during high flow periods below the dam and a pattern of decreased sediment transport and increased retention below the dam. Initial results have serious implications to benthic invertebrates, many of which require cobble substrates for colonization. The preliminary results on habitat alteration below the Oldman Dam do not support the predictions of the SDC.
DE: 1803 Anthropogenic effects
DE: 1824 Geomorphology (1625)
DE: 1845 Limnology
DE: 1860 Runoff and streamflow
DE: 9902 NABS Student Award Applied Research
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly