HR: 09:45h
AN: NB51E-05 INVITED     [Abstracts]
TI: The Importance of Flow, Thermal, and Resource Pulses for Floodplain Processes
AU: * Tockner, K
EM: klement.tockner@eawag.ch
AF: EAWAG, BOX 611, Duebendorf, 8600 Switzerland
AU: Langhans, S D
EM: sinome.langhans@eawag.ch
AF: EAWAG, BOX 611, Duebendorf, 8600 Switzerland
AU: Doering, M
EM: michael.doering@eawag.ch
AF: EAWAG, BOX 611, Duebendorf, 8600 Switzerland
AU: Tanner, C
EM: christoph.tanner@empa.ch
AF: EMPA, Ueberlandstrasse 133, Duebendorf, 8600 Switzerland
AU: Uehlinger, U
EM: urs.uehlinger@eawag.ch
AF: EAWAG, BOX 611, Duebendorf, 8600 Switzerland
AB: In floodplains, flow, temperature, and resource pulses interact in complex ways and maintain biodiversity and biological productivity in these systems. We investigated the driving force of multiple pulses (i.e. flow, temperature, resource) on ecosystem processes in semi-natural floodplains in Central Europe (Val Roseg, Tagliamento, Danube). We used imaging techniques to quantify thermal patch dynamics over diel cycles and inundation patterns at the landscape scale. In the proglacial Val Roseg floodplain, surface temperature exhibited a complex spatiotemporal pattern, with values from -5° C to 30° C over a diel cycle. Furthermore, we studied the differential effects of alternating drying and wetting cycles on leaf litter decomposition and sediment respiration. Based on these data, we identified key habitats of ecosystem processes at the floodplain scale. Locations of organic matter input, storage, and processing were spatially separated. In the Tagliamento, standing stock of CPOM, for example, was up to 800g/m2 on vegetated islands but less than 20g/m2 in channels. Decomposition rate, however, was k = 0.0129 in channels compared to k = 0.0013 on islands. Finally, by overlaying different pulses, we identified "windows of ecological opportunity"; i.e., crucial time periods when conditions were most favourable to foster ecosystem processes and therefore to control floodplain biota.
UR: http://www.eawag.ch
DE: 9810 New fields (not classifiable under other headings)
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly