1. Rivers X-GIG phytobenthos intercalibration
Martyn Kelly

2. Phase 1 outcomes CB & N GIGs Several open issues
Partial intercalibration (diatoms only) for 12 MS (CB) and 4 MS (N)
Several open issues
Quality of reference screening
Relevance of IC typology
Effect of non-intercalibrated components and interaction with macrophytes
Are phase 1 results consistent with phase 2 criteria?

3. Intercalibration Common Metric
ICM = average of EQR-IPS and EQR-TI
Regression between national metric and ICM used to convert national boundary values to “common currency”
e.g. Flanders national metric

4. Phase I achievements

5. Validation of phase 1 reference criteria
X-GIG exercise
Developed a common database
Reference screening by University of Vigo
Taxonomic harmonisation exercise

6. NDMS of screened reference sites
Some separation between GIGs;
effect of MS overrides effect of IC type

7. GIG / IC type differences in pICM

8. Threshold values for pICM
Mean value for GIG ± 2 standard deviations
ALP CB EC
MED N
X-GIG
IPS
15.2
14.4
10.7
13.3
16.3
13.9
IPS-adj
15.6
12.3
13.5
16.1
14.3 TI
2.33
3.55
4.60
3.03
2.23
3.22
TI-adj
3.48
4.69
3.05
2.06
3.18

9. Application to phase 1 reference data

10. Evaluation of “phase 1” results using “phase 2” criteriaMS
H/G
G/M AT
Austria
0.11
0.03
BE-FL
Belgium-Flanders
0.40
0.62
BE-WA
Belgium-Wallonia
0.44
0.30 DE
Germany
0.15
0.24 EE
Estonia
-0.15 ES
Spain FR
France
-0.31
-0.01 IE
Ireland
0.08
0.72 LU
Luxembourg
-0.26
-0.02 NL
Netherlands
0.04
-0.03 SE
Sweden
-0.05 UK
United Kingdom
Median H/G and G/M recalculated excluding LU; “phase 2” calculations applied.
MS who contribute to calculation of medians tend to have acceptable bias
Other MS tend to be more stringent

11. New and adjusted methodsMS
Phase
Boundary as national EQR
Bias as class width
H/G
G/M EE
Estonia 1
0.85
0.70
-0.36
0.95 2
0.38
0.57 ES
Spain
0.93
0.7
0.40
0.30
(Types 1 & 2)
-0.29
0.10
(Types 3 & 4)
0.92
1.56 IT
Italy
0.84
0.65
-0.26
-0.07 FR
France
-0.45
-0.02
0.94
0.78
0.02
0.19 LU
Luxembourg
-0.33
-0.06
0.90
0.00
-0.05 PL
Poland (RC1, RC3, RC99)
0.80
0.58
0.03
Poland (RC4, RC5)
0.8 UK
United Kingdom
0.42
1.00
0.75

12. Effect of initial assumptions
Phase 2 work started with the assumption that boundaries set by MS in good faith during phase 1 should be respected unless serious failings were revealed
The tendency towards stringent boundaries for MS who did not contribute to the mean boundary has also been assessed ….
… mean boundary value recalculated using all MS with reference sites (excluding IT – v. small dataset)

13. MS with acceptable (“OK”) or unacceptable (“not”) levels of bias
MS with ref sites
MS without ref sites
bias
H/G OK
not
Not
original calculations (phase 1) 6 2 3
new common boundary - mean 8 4 1
G/M
original calculations (phase 1) 5
Re-calculated boundaries are slightly higher than phase 1 boundaries.
Using these, there is a slight reduction in overall bias

14. N GIG Similar principles to CB GIG
Fewer MS (4 in phase 1; 5 in phase 2)
Fewer problems with reference screening
Different ICM:
TISImin – minimum of TI and SI
TISImean – average of TI and SI

15. Re-analysis of N GIG results
TISImin MS
Phase
Reference samples
H/G
G/M FI
Finland 1 OK
-0.04
-0.16 IE
Ireland
-0.45 SE
Sweden
0.02
0.17 UK
United Kingdom
0.01
0.08 2
TISImean MS
Phase
Reference samples
H/G
G/M FI
Finland 1 OK
-0.19 IE
Ireland
-0.41
-0.03 SE
Sweden
0.18
1.75 UK
United Kingdom
0.00
0.06 2
0.01
-0.07

16. Adding Norway to N GIG Norway has a metric that does not use diatoms.
Intercalibration involved collecting a parallel set of diatom samples, and using these to establish the position of the NO boundaries on the pICM scale.

17. Evaluation of NO boundaries
TISImin MS
Step
Boundary as national metric
Bias, as class width
H/G
G/M NO
Ca ≤ 1
0.99
0.83
0.22
0.06
Ca > 1
0.95
0.08
TISImean MS
Step
Boundary as national metric
Bias, as class width
H/G
G/M NO
Ca ≤ 1
0.99
0.83
0.38
0.10
Ca > 1
0.95
0.14

18. Summary CB-GIG N-GIG Phase 1 results are mostly sound
Several MS have voluntarily adjusted boundaries
DK, CZ, LV, LI, SI and SK have not submitted methods
CZ, IE, ES have new/modified methods close to completion
N-GIG
NO has been included in phase 2; UK has adjusted phase 1 boundaries
All MS in N GIG have now submitted methods