Ecological monitoring and assessment of pollution in rivers - Ecology of Industrial Pollution - page 139

Table 6.3. Acid Water Indicator Community (AWIC) Index scores of invertebrate
families (reproduced from Davy-Bowker et al. 2005 )

Taxon Score Taxon Score Taxon Score

Ephemeridae 6 Psychomyiidae

(inc. Ecnomidae)

6 Hydropsychidae 4

Physidae 6 Sphaeriidae 6 Tipulidae 4

Piscicolidae 6 Hydrobiidae

(inc. Bithyniidae)

6 Chironomidae 4

Planorbiidae 6 Caenidae 6 Sericostomatidae 4

Valvatidae 6 Ancylidae

(inc. Acroloxidae)

6 Limnephilidae 4

Asellidae 6 Leptoceridae 6 Goeridae 4

Haliplidae 6 Perlidae 6 Planariidae (inc.

Dugesiidae)

4

Corixidae 6 Erpobdellidae 6 Philopotamidae 3

Lymnaeidae 6 Odontoceridae 6 Gyrinidae 3

Hydroptilidae 6 Baetidae 6 Simuliidae 3

Gammaridae (inc.
Crongonyctidae
& Niphargidae)

6 Dytiscidae

(inc. Noteridae)

6 Perlodidae 2

Leptophlebiidae 6 Scirtidae 6 Lepidosto-

matidae

2

Glossiphoniidae 6 Hydrophilidae

(inc. Hydraenidae)

6 Taenioptery-

gidae

2

Calopterygidae 6 Heptageniidae 6 Polycentro-

podidae

1

Sialidae 6 Oligochaeta 6 Leuctridae 1

Ephemerellidae 6 Rhyacophilidae

(inc. Glossosomatidae)

6 Nemouridae 1

Coenagrionidae 6 Elmidae 6 Chloroperlidae 1

By dividing assessment quality into classes, there is a possibility that sites will
be misclassified, and the probability of misclassification occurring is influ-
enced by how much variation there is in the observed biota relative to the
width of the classes ( Fig. 6.3 ) . This variation is attributable to:

1. sampling variation due to random or systematic differences between

samples collected

2. sample processing errors caused by sub-sampling, sorting and identification

3. 'natural' temporal variation

4. the effects of pollution, environmental stress or remediation.