A comparison of different pre-treatment procedures for reducing heteroscedasticity and other irrelevant features in data prior to modelling of benthic count profiles
Challenges related to quantifying environmental disturbance biologically from benthic count profiles by using the Community Disturbance Index (CDI) approach are assessed. A pre-treatment framework incorporating removal of irrelevant features, scaling and converting transformations is proposed. Within this framework the characteristics of benthic count data are discussed and possible consequences for the CDI calculations are shown. It is established that the benthic count data need to be corrected for heteroscedasticity while scaling is found to be unnecessary for the CDI calculations. Copyright (c) 2007 John Wiley & Sons, Ltd.
pre-treatment community disturbance index (cdi) scaling transformation environmental modelling heteroscedastic noise benthic community