Detectability of fifteen aquatic micro/mesocosms.
Zooplankton abundance and species richness in 15 untreated 12,000 L outdoor microcosms (n = 15) were monitored over the course of 1 year to document the inherent variability and statistical detectability between replicates. Statistical power analysis were applied to derive the statistically minimal detectable difference (MDD) between replicates with default values set at; alpha = 0.1 and beta = 0.2. Copepod abundance and species richness generally demonstrated the best detectability at 0.31 and 0.16, respectively, (n = 15); 0.59 and 0.33 (n = 3). Total zooplankton abundance and species richness had the lowest detectabilities at 0.19 and 0.14, respectively, (n = 15); 0.35 and 0.3 (n = 3). Rotifers, due to their opportunistic and rapid life traits, had the lowest single-species abundance detectabilities at 0.54 (n = 15); 0.8 (n = 3), whereas macroinvertebrate species richness had the lowest detectability at 0.43 (n = 15); 0.7 (n = 3) over 1 year. We recommend a priori calibration of the study design relative to relevant MDDs. Moreover, it is suggested to consider alternatives to statistical null hypothesis testing.
Sanderson
Hans
H
Department of Policy Analysis, National Environmental Research Institute, Aarhus University, Frederiksborgvej 399, Post Box 358, 4000, Roskilde, Denmark. hasa@dmu.dk
Laird
Brian
B
Brain
Richard
R
Wilson
Christian J
CJ
Solomon
Keith R
KR
D000818:Animals; D033342:Copepoda / Q000187:drug effects / Q000254:growth & development; D017753:Ecosystem; D054750:Ecotoxicology / Q000379:methods*; D004784:Environmental Monitoring / Q000379:methods*; D005618:Fresh Water; D015233:Models, Statistical; D015203:Reproducibility of Results; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D015048:Zooplankton / Q000187:drug effects* / Q000254:growth & development
D014874:Water Pollutants, Chemical