title: Analysis of community-level mesocosm data based on ecologically meaningful dissimilarity measures and data transformation.
abstract: The principal response curve (PRC) method is a constrained ordination method developed specifically for the analysis of community data collected in mesocosm experiments, which provides easily understood summaries and graphical representations of community response to stress. It is a redundancy analysis method and is usually performed on log-transformed abundance data. The choice of a measure of dissimilarity between samples and the choice of the data transformation significantly affect the results of multivariate analysis. Dissimilarity measures that are more ecologically meaningful than the Euclidean distance can be incorporated into the PRC using distance-based redundancy analysis. The present study investigates the ordinations produced by a small selection of dissimilarity measures: the Euclidean distance using log-transformed and Hellinger-transformed data and the Bray-Curtis dissimilarity using raw and log-transformed data. It compares 2 data sets from experiments on the effect of the anti-inflammatory drug diclofenac and the insecticide chlorpyrifos on macroinvertebrate communities. The choice of dissimilarity measure can determine the outcome of a risk assessment. For the diclofenac data set, the PRCs were different depending on the dissimilarity measure: the community no-effect concentration was lowest for the Bray-Curtis on log-transformed data and Hellinger dissimilarity measures. For chlorpyrifos, however, the PRCs were similar for all dissimilarity measures. Environ Toxicol Chem 2017;36:1667-1679. © 2016 SETAC.
authors.affiliation: Models for Ecotoxicology and Toxicology Unit, INERIS, Verneuil-en-Halatte, France.
authors.forename: Cleo
authors.initials: C
authors.lastname: Tebby
authors.affiliation: Ecotoxicology Unit, INERIS, Verneuil-en-Halatte, France.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Joachim
authors.affiliation: Aquatic Ecology and Water Quality Management Group, Wageningen University, Wageningen, The Netherlands.|Wageningen Environmental Research (Alterra), Wageningen, The Netherlands.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Van den Brink
authors.affiliation: Ecotoxicology Unit, INERIS, Verneuil-en-Halatte, France.
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Porcher
authors.affiliation: Models for Ecotoxicology and Toxicology Unit, INERIS, Verneuil-en-Halatte, France.
authors.forename: Rémy
authors.initials: R
authors.lastname: Beaudouin
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000633:toxicity; D004390:Chlorpyrifos / Q000633:toxicity*; D004008:Diclofenac / Q000633:toxicity*; D017753:Ecosystem; D007306:Insecticides / Q000633:toxicity; D008954:Models, Biological; D015999:Multivariate Analysis; D014874:Water Pollutants, Chemical / Q000633:toxicity
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D007306:Insecticides; D014874:Water Pollutants, Chemical; D004008:Diclofenac; D004390:Chlorpyrifos
keywords: Aquatic toxicology; Dissimilarity measure; Ecological risk assessment; Mesocosm; Multivariate statistic; Principal response curve