Page 222 - Freshwater-Biology-and-Ecology-Handbook

CHAPTER 5 3.1.4 – 3.1.5 3.1.4 BMWP (Biological

Monitoring Working
Party) indices

The Biological Monitoring Working Party score (BMWP-
score), and its derivations, Average BMWP-score per taxon
(ASPT or BMWP ASPT), and number of BMWP-scoring taxa
(Ntaxa or BMWP Ntaxa) have been superseded in the UK
by substantially revised versions known as WHPT (Walley
Hawkes Paisley Trigg) indices (Hawkes 1998) (78) (Chapter
3 Section 2.2, Chapter 5 Section 3.1.5). BMWP is still used
by the Environment Agency for Hydroecological Validation
(HEV) for managing water resources (Section 3.2.5). The
BMWP indices are still used outside the UK (Herman &
Nejadhashemi 2015) (79) and as components of multi-metric
indices, such as ICMi (Section 3.1.7).

BMWP – Biological Monitoring
Working Party indices

BMWP indices (score, ASPT and Ntaxa) are precursors
of the current WHPT indices, but are still used to assess
environmental quality, principally for organic pollution.

BMWP has been used successfully around the world in both
temperate and tropical countries. This is because species
within families tend to have the same respiratory physiology
and because most families are pandemic.
Beware, there are different versions of BMWP indices.
The original had separate index values for eroding and
depositing streams, but the versions used for the 1980 and
1990 national river quality surveys had one set of values
for all stream types. From 1995, the regulatory agencies
excluded Clambidae, Chrysomelidae and Curculionidae
because they are very rare or absent from running waters.
BMWP indices follow the taxonomy described in the coded
checklist of freshwater animals by Maitland (1977) (80) which
helps us to continue to use it despite taxonomic changes
since then. Some families that we recognise now as distinct
families are combined as BMWP-composite taxa.

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