HR: 14:45h
AN: NB23D-06    [Abstracts]
TI: a Comparative Study of Techniques to Elucidate the Relative Importance of Autochthonous and Allochthonous Resources in Tropical Streams
AU: * Lau, D C
EM: h0030073@hkusua.hku.hk
AF: Department of Ecology & Biodiversity, The University of Hong Kong, Pokfulam Rd, Hong Kong
AU: Dudgeon, D
EM: ddudgeon@hkucc.hku.hk
AF: Department of Ecology & Biodiversity, The University of Hong Kong, Pokfulam Rd, Hong Kong
AU: Leung, K M
EM: kmyleung@hkucc.hku.hk
AF: Department of Ecology & Biodiversity, The University of Hong Kong, Pokfulam Rd, Hong Kong
AB: To determine whether allochthonous or autochthonous energy resources are more important to aquatic consumers in tropical streams with different degree of riparian shading, stoichiometric analysis (STA of C and N), fatty acid profiling (FAP) and bulk tissue C and N stable isotopic analysis (SIA) were undertaken. Basal food sources (leaf litter, periphyton, cyanobacteria) and common consumer species (snails, shrimps, fishes) were collected in three Hong Kong (China) streams (2 shaded and 1 unshaded) in the dry season of 2004. The results showed that the primary consumers relied primarily on the autochthonous sources, even in the shaded streams. Further investigation focused on laboratory populations of the omnivorous snail Brotia hainanensis (Pachychilidae) that were fed for six months with periphyton or Liquidambar formosana (Hamamelidae) leaf litter. The results of STA, FAP and SIA of these animals with known feeding history were compared with field-collected individuals. SIA and FAP were generally more sensitive than STA in elucidating basal food sources of the consumers in all cases, and the laboratory feeding trials confirmed the autochthonous 'signal' in diets of field-collected animals. SIA and FAP yielded complementary but non-identical results, and their combined use in studies of food webs is recommended.
DE: 1845 Limnology
DE: 9903 NABS Student Award Methodology
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly