Response to Frutiger & Schib (1993) ‘Limitations of FST hemispheres in lotic benthos research’

Abstract

This response to the paper of Frutiger & Schib (1993) focuses on substantial errors that are relevant to the interpretation of results and deficiencies in their study design. I include some reanalysis of the original data of Schib (1991), which formed the basis of Frutiger & Schib's paper.  The paper of Frutiger & Schib (1993) is flawed because of their sampling strategy (sequence of measurements, depth stratification, and the long duration of the study in relation to temporal changes in the insect populations), the selection of study sites (one lake outlet, one river disturbed by bathers), the mixing of single‐species and multiple‐species units in the analysis, the pooling of data and its analysis, the omission of essential information given by Schib (1991), and the generation of doubtful arguments. Their approach and interpretation places FST hemispheres at an unreasonable disadvantage in a debate about the relative utility of hemispheres and propeller‐type current meters and consistently discriminates against the general role hydraulics play in the micro‐distribution of the eight insect taxa that were studied.  Despite the deficiencies of their study, my reanalysis of the original data of Schib (1991) provides significant models of insect abundance in relation to hemisphere density for six of the eight insect taxa, with r2 values between 0.62 and 0.86 for five of them. Copyright © 1993, Wiley Blackwell. All rights reserved