Page 118 - Freshwater-Biology-and-Ecology-Handbook

CHAPTER 2 12.5 – 12.6 12.5 Identification The main differences in sensitivities of species within a genus

For environmental quality assessment, family is generally the
minimum level of identification based on the taxa included
or family often involve the natural environmental pressures
that determine their habitat, such as substrate and stream
in the WHPT index. That enables WFD quality status to
size. To summarise: you need to decide on the diagnostic
be established and it is also sufficient for the calculation
of a number of other biotic indices to help diagnose
indices you want to apply, as different diagnostic indices
environmental pressures.
Despite being particularly useful for environmental
Species-level analysis provides more data from which
assessment, some species, including Oligochaeta and
to diagnose environmental degradation. This may require different levels of identification.
provide greater accuracy necessary to detect emerging Chironomidae are difficult to identify. An operational
environmental pressures that have more subtle impacts, compromise, known as ‘mixed taxon analysis’, is used
such as climate change, the impacts of some invasive to identify groups that are readily identifiable to species,
species, and morphology. Species-level identification and to identify other groups to a higher level. This is the
is generally needed for conservation analysis. However, standard level of analysis used by the Environment Agency.
its advantages for environmental assessment are often In addition to advantages already mentioned for species-
overstated. Precision is limited by sampling and the response level identification, it provides information from which to
of many species to common anthropogenic environmental develop improved indices, and to assess the impacts of
pressures such as organic enrichment is similar to that of new pressures such as climate change and alien invasive
other species in the same family. species. This is summarised in Table 2.7.

Table 2.7
Taxonomic levels recognised by RIVPACS

Taxonomic level Description Notes

Taxa (families + Oligochaeta) recognised by
TL1 BMWP (Biological Monitoring Working Party) families
BMWP indices
Taxa (families + Oligochaeta) recognised by
TL2 WHPT (Walley Hawkes Paisley Trigg) families
WHPT indices
TL3 All RIVPACS families Families recognised by RIVPACS

Species recognized by RIVPACS; includes
TL4 All RIVPACS species some composite species and higher taxa that
are not differentiated

Standard level of analysis used by
TL5 Mixed taxon level
environmental protection agencies

These taxonomic levels are described in more detail in a report by Davy-Bowker et al. (2010), (32) which includes appendices
listing their constituent taxa, and is available from the Reports page of the RICT2 web pages https://www.fba.org.uk/
rivpacs-and-rict/rivpacs-rict-resources

Further development of River Invertebrate Classification Tools can be found in this final report https://www.sniffer.org.
uk/wfd100

118 | Freshwater Biology and Ecology Handbook
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