HR: 1330h
AN: NB33H-05    [Abstracts]
TI: Spatial Heterogeneity of Leaf Litter Decomposition in a Complex Mosaic of Floodplain Habitats
AU: * Langhans, S D
EM: simone.langhans@eawag.ch
AF: EAWAG/ETH, Department of Limnology, Ueberlandstrasse 133, Duebendorf, ZH 8600 Switzerland
AU: Tockner, K
EM: klement.tockner@eawag.ch
AF: EAWAG/ETH, Department of Limnology, Ueberlandstrasse 133, Duebendorf, ZH 8600 Switzerland
AB: Dynamic floodplains comprise complex mosaics of aquatic, amphibious, and terrestrial habitats that are expected to mediate input, storage and transformation of organic matter. We examined leaf litter breakdown heterogeneity in a complex floodplain ecosystem (Tagliamento, NE Italy), separated the differential effects of microbes and shredding macroinvertebrates on leaf breakdown, and identified key habitats of leaf litter transformation. We employed a leaf-bag approach, using coarse and fine mesh bags, designed to allow or exclude feeding by stream invertebrates. Bags were exposed in eight habitat types, representing the dominant range of floodplain habitats. Breakdown rates varied by an order-of-magnitude, ranging from k = -0.0013 to k = -0.0129 day ^-1. Results showed that leaf breakdown in coarse mesh bags differed significantly among channels, ponds, and terrestrial habitat types. In fine mesh bags, however, only channels had significantly higher leaf breakdown rates. Leaf decomposition was similar in all terrestrial habitat types despite extensive variability in environmental conditions. Our study emphasizes that floodplain habitats display a remarkable heterogeneity in their ability to process organic matter, whereas lotic and lentic habitats were clearly identified as "hot spots" of leaf litter transformation.
DE: 9810 New fields (not classifiable under other headings)
DE: 9901 NABS Student Award - Basic Research
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly