Lakes and Watercourses

Assessment of current conditions
TABLE 39.
CURRENT CONDITIONS: bottom fauna index, watercourses
(riffle areas)
Class Description Shannon’s ASPT- Danish Acidity
diversity index fauna- index
index
index
1 Very high index > 3.71 > 6.9 7 > 10
2 High index 2.97 – 3.71 6.1 – 6.9 6 6 – 10
3 Moderately high index 2.22 – 2.97 5.3 – 6.1 5 4 – 6
4 Low index 1.48 – 2.22 4.5 – 5.3 4 2 – 4
5 Very low index ≤ 1.48 ≤ 4.5 ≤ 3 ≤ 2
TABLE 40.
CURRENT CONDITIONS: bottom fauna index, littoral zone of lakes
(exposed shores)
Class Description Shannon’s ASPT- Danish Acidity
diversity index fauna- index
index
index
1 Very high index > 3.00 > 6.4 > 5 > 8
2 High index 2.33 – 3.00 5.8 – 6.4 5 6 – 8
3 Moderately high index 1.65 – 2.33 5.2 – 5.8 4 3 – 6
4 Low index 0.97 – 1.65 4.5 – 5.2 3 1 – 3
5 Very low index ≤ 0.97 ≤ 4.5 ≤ 2 ≤ 1
Apart from the acidity index, class boundaries are based on statistical
breakdowns, where classes 1 and 5 are delimited by the 90th and 10th
percentiles (O/C index 10th and 90th) and where the other class
boundaries are divided evenly between the extremes. The class boundaries
for the acidity index reflect the occurrence of various species along a
pH gradient (see Appendix 2).
67