Comparison of macroinvertebrate sampling methods in Europe

The aim of this study was to describe in detail the national macroinvertebrate sampling methods used and to compare them with a common standard, the STAR-AQEM sampling method. Information on national methods and field data were collected from 11 countries (Austria, Czech Republic, Denmark, France, Germany, Greece, Italy, Latvia, Portugal, Sweden, and UK). The sampling included 22 stream types situated in 11 different Ecoregions. Within each country samples were taken in spring and one additional season (summer or autumn) using both the national method and the STAR-AQEM method. A single anthropogenic stressor was also defined for each stream type sampled within the project, with the three main stressor types being organic pollution (including eutrophication), toxic pollution and habitat degradation. In addition, not impacted reference sites were sampled in each country. A common set of metrics was calculated and compared between the methods. The majority of national methods employed had many features in common. Most of the 12 metrics analysed using the values derived from the STAR-AQEM method and the various national methods correlated significantly, and positively to each other. There was no clear pattern with respect to the differences between metric results obtained using STAR-AQEM and national methods. For some metrics, number of EPT-taxa and families, the value obtained was higher when using the majority of national methods when compared to the STAR-AQEM method. Variability in metric results between methods could not be explained from differences in sampling effort. Sorting in the field and sub-sampling appeared to affect e.g., number of taxa found negatively. The results of the present study supports that inter-calibration in Europe can be undertaken using samples collected with the existing national methods.