Page 205 - Freshwater-Biology-and-Ecology-Handbook

3.4.5 Excavation

This technique is described by Sadler & Petts (2000). (68)
At a distance of 1 to 2 m from the river’s edge, a garden
trowel is used to dig out an area of approximately one
square metre down to the water table. The sides of the
excavation are then collapsed down into the ponded water
so that animals trapped in the sediment float to the surface
where they can be scooped up with a tea-strainer. The
time allotted for the excavation of shingle should be 15 to
20 minutes. Excavation works best on sand and shingle
but cannot be used for finer grade silts or on very coarse
boulders.

It takes some practice to work out where such excavations
are best situated. On shingle they are often more
productive in the finer grade material at the leading edge of
a shingle bar.
3.4.6 Reporting on the

riparian fauna

Important aspects of the fauna to analyse should include
the number of species with a high fidelity to riparian and
floodplain habitats, as well as rarity and other scoring
metrics. Reports should emphasize on-site features of
interest and use comparative analysis to help classify a
site’s importance. Selected elements from Pantheon (an
online tool to analyse invertebrate species samples) can be
used to help interpret and understand riparian interest. (69)
(see Chapter 5 Section 3.2.6 Pantheon).

(66)
Useful references include Drake et al. (2007),
Webb et al. (2017), (69) and Webb et al. (2022). (65)

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