Replicate samples of cobbles and loose inorganic and organic matter collected from 3 stream-riffle sites with different periphyton communities were passed through a geometric series of 9 sieves (0.063–16 mm mesh) to quantify sieve retention probabilities of benthic invertebrates. Sieves retained all organisms with a body length >10× the mesh size. Logistic regression models were estimated to describe retention probabilities as functions of body length and mesh size. Retention probability functions differed slightly but significantly among sites, operators, and taxa. Retention probabilities were higher for samples containing filamentous algae, which entangled invertebrates. Size distributions of straight, elongate invertebrates (e.g., oligochaetes, midge larvae) retained by sieves were more variable than distributions of more spherical organisms (e.g., gastropods). On average, the 1-mm sieve retained >90% of invertebrate biomass but <33% of individuals retained by a 63-μm sieve. Size distribution of organisms retained by coarse sieves (≥1 mm), combined with logistic functions predicting retention probability, can be used to describe abundance, biomass, and size distribution of organisms retained by fine sieves. These results suggest that unbiased descriptions of benthic communities can be obtained with relatively little effort by using a minimum sieve mesh size of 1 mm.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 23 • No. 2