CNR-IRSA activities related to INHABIT

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Sampling

Surber net is used for sampling shallow habitats (approx. <0.5 m). Sampling area for each unit is 0.05 or 0.1 m2. According to site stream type total sampling area is 0.5 or 1 m2 (i.e. 10 units x 0.05 or 10 units x 0.1). If substrates deeper than 0.5 m are sampled then a handnet modified with a frame delimiting sampling area should be used. Mesh size for all sampling instruments (Surber or handnet) is 500 µm.
Sampling site is representative of a wider reach of the stream, i.e. where possible of the whole water body (sensu WFD). The sampling starts at the downstream end of the site and moves upstream in order to avoid unnecessary habitat disturbance. If a Surber sampler is used then hands are used for disturbing the substrate. Where a handnet is used both hands and feet can be used, although use of hands is preferable.
Site sample is formed by all the sample units collected. However, in order to ease sorting procedures, it is suggested to sort separately units with vegetal debris and collected on fine substrates (e.g. sand or silt). It is anyway suggested to empty the sampling net after the sampling of 3 or 4 replicates.
If sampling is performed with special aims (e.g. research activities or improved surveillance or investigative monitoring), animals sampled in the single units can be kept separately, in particular if collected in different areas of the river (i.e. pool vs riffle).