Discussion of Daniels and McCusker (2010): 'Operator bias characterizing stream substrates using Wolman pebble counts with a standard measurement template' Geomorphology 115 194-198

摘要

We feel that the presence of misinterpretations and omissions regarding pebble count utility and application in Daniels and McCusker (2010) warrants a response. Claiming to have done what the authors call a "standard Wolman pebble count," the article by Daniels and McCusker (2010) can give the false impression that use of a template (or gravelometer) does not contribute toward reducing operator variability. Looking at the study in detail shows that while the authors minimized errors in particle size measurement, they did not minimize the particle selection bias.