Observations on the vertical distribution of the benthos in a Malaysian stream

An apparatus is described wbich is capable of sampling tbe bentbic fauna to a depth of 50 cm by providing a natural substrate for colonization. Tbe results obtained from an area of visually uniform sediments demonstrate that stream animals occur in significant numbers deep in tbe bottom sediments and that, at most, only about half tbe bentbos lives in tbe upper 10 cm usually ‘quantitatively’ sampled in stream surveys. The significance of a deep-living fauna in regulating community density, in recolonizing denuded areas and in optimizing utilization of available food resources is discussed.