Foodweb structure in a tropical Asian forest stream

Abstract

AbstractA food web based on the gut contents of consumers (invertebrates and fishes) in pools of Tai Po Kau Forest Stream (TPKFS), Hong Kong (southern China), indicated the importance of periphyton and fine organic particles; coarse particulate organic matter was a less important food source despite its higher relative abundance in this shaded hillstream. Stable isotope analysis of consumer tissues was undertaken to confirm this result. IsoSource software was used to model n-isotope and >n + 1-sources, so that the relative contribution of the potential food sources could be determined. Results of an IsoSource mixed model of δ15N and δ13C stable isotope signatures of primary consumers generally supported evidence from gut content analyses about the importance of autochthonous resources. Inconsistencies between the results of gut content analysis and isotope signatures of consumer tissues occurred in a few cases but could be explained either by small sample size or the wide range of feasible solutions provi...