Page 248 - Freshwater-Biology-and-Ecology-Handbook

CHAPTER 5 3.1.23 3.1.23 Urban Riverfly index

(by Nicola Edgar, Environment Agency)

Urban Riverfly is a Riverfly Plus scheme that uses an
extended list of taxa compared to the original Anglers’
Riverfly Monitoring Initiative index, but not so many as
Riverfly Plus. It can be used across several different river
systems. The addition of 6 more invertebrate groups to
the original 8 provides greater sensitivity to help with the Urban Riverfly
evaluation of pressures. The extra groups comprise worms, Urban Riverfly is a Riverfly Plus citizen science index
snails, beetles, leeches, blackfly larvae (Simuliidae) and that uses an extended list of invertebrate families to
freshwater hoglouse (Asellidae). They are all easy to identify detect pressures in urban rivers where many of the
(Figure 5.8) and are more pollution tolerant invertebrates invertebrates used in ARMI are likely to be absent
that are commonly recorded in urban and modified rivers.

The index values (Table 5.11) are impacted both positively The survey method remains the same as the traditional
and negatively by abundance, so they are more reflective ARMI with a 3-minute kick sample and 1-minute hand search.
of WHPT which is the standard index used by the UK’s Because its index values depend on abundance, it is only
environmental protection agencies. Pollution tolerant groups suitable for samples collected by the standard RIVPACS
such as leeches, worms and the freshwater hoglouse have methods.
lower index values as abundances increase.

Table 5.11
Index values for the urban riverfly index

Abundance
1–9 10–99 100–999 1000 +

Cased caddis 1 2 3 4

Caseless caddis 1 2 3 4
Stoneflies 1 2 3 4 The urban riverfly index is
calculated in the same way as the
Mayfly (Ephemeridae) 1 2 3 4
ARMI index. However, the index
Mayfly (Ephemerellidae) 1 2 3 4 values for the additional indicators
are not all the same. Survey
Mayfly (Heptageniidae) 1 2 3 4 results are currently stored on
Cartographer.
Mayfly (Baetidae) 1 2 3 4
A pilot of this scheme was started in
Freshwater shrimp – Gammarus 1 2 3 2
the Midlands (England) where both
Blackfly larvae (Simuliidae) 1 2 2 0 new and existing volunteers were
provided with one day’s training.
Beetles 1 2 3 4
The scheme was launched nationally
Snails 1 1 1 0 at the Riverfly Conference in March
2020.
Leeches 1 1 0 -2
Limited information is available from
Freshwater hoglouse (Asellidae) 1 1 0 -2
https://www.riverflies.org/urban-
Worms (Oligochaeta) 1 1 0 -3 riverfly

248 | Freshwater Biology and Ecology Handbook
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