Sampling method for rivers, based on AQEM/STAR
The method is based on the proportional representation of the bottom substrates at the sampling site (Multi-Habitat-Sampling).
Sampling includes the following steps:
The coverage of bottom substrates is estimated in 5% steps.
20 sampling units, each covering an area of approx. 0.25 x 0.25 m, must be taken. Allocation of sampling units must reflect habitat composition (one sampling unit per 5% substrate coverage).
Optional treatment of the collected material by sieving and/or separating the coarse mineral fraction.
A 21st sampling unit is taken, when rare habitats (< 5% coverage of bottom substrates) are present.
The remaining material is preserved and further processed in the lab.
Live sorting in the field.
A detailed description, including exceptional cases such as partial-wadable rivers, is given in the "river assessment manual” (only in German).