HR: 16:15h
AN: NB24C-04    [Abstracts]
TI: The Importance of Insects in Energy Transfers Across Riparian Ecotones Along Hong Kong Streams
AU: * Chan, E K
EM: h9941424@hkusua.hku.hk
AF: Department of Ecology & Biodiversity, The University of Hong Kong, Pokfulam Road, Hong Kong
AU: Dudgeon, D
EM: ddudgeon@hkucc.hku.hk
AF: Department of Ecology & Biodiversity, The University of Hong Kong, Pokfulam Road, Hong Kong
AB: Energy and materials in the form of insects transfer reciprocally between land and water through stream riparian ecotones, and may provide important energy subsidies to aquatic and terrestrial consumers. Variation in the magnitude and extent of this transfer was investigated in 2004-05 in six Hong Kong streams: four shaded and two unshaded. A combination of pan traps and light traps were used to investigate seasonal activity of aquatic and terrestrial insects. Both were more abundant during the wet season (April to September). Over 80% of emerging aquatic insects stayed within 20 m of the stream bank at all sites, suggesting that the water to land subsidy was spatially restricted. Inputs of terrestrial insects into shaded streams were 30% greater than at open sites, and drift-feeding Parazacco spilurus (Cyprinidae) ate more terrestrial insects in shaded (>40% of prey) than unshaded streams (25% of prey). Stable isotope analysis (SIA; C & N) of potential prey and fish tissues confirmed the dietary importance of terrestrial insects. The spider Leucauge celebesiana (Tetragnathidae) builds orb web parallel to the water surface during the main period of aquatic insect emergence, and SIA indicated that aquatic insects were the primary prey of this terrestrial consumer.
DE: 1845 Limnology
DE: 9901 NABS Student Award - Basic Research
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly