Page 243 - Freshwater-Biology-and-Ecology-Handbook

Table 5.9
Relationship between significance, indicator, sensitivity group. Compiled from information in Paisley et al. (2011) (112)
and Everall et al. (2019), (110) with tolerance definitions from Supplementary Information A from Everall et al. (2019). (110)

Significance Sensitivity TRP tolerance Nutrient score according to log abundance
of MI Indicator Group definition categories

1–9 10–99 100–999 1000 +

1% - A Very sensitive 2 3 4 5

5% - B Sensitive 1 2 3 4

5% + C Tolerant 1 2 3 4
1% + D Very tolerant 2 3 4 5

Indifferent or excluded
>5% E - - - -
for other reasons

TRPI is calculated as the percentage of phosphorus sensitive indicators.

To determine TRPI you will have to identify the site type substrate percentage of boulders, pebbles, sand and silt)
and then refer to tables in Supplementary Information from identified by a standard back-propagation neural network,
Everall et al. (2019) (110) to determine the sensitivity groups, not on discrete bands of the variables (Walley and Fontama
because families can belong to a different sensitivity group in 1998). (113)
a different site type or season. Although Everall et al. (2019)
gives a table defining each site type it cannot identify the site Because TRPI index values depend on abundance, it can
type in all cases. This is because they were originally based only be calculated from samples collected by standard
on the overall pattern of six variables (altitude, alkalinity, and RIVPACS methods.

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