1. Validation and alternative approaches
Lessons from your own analyses:
Am I using the most appropriate BQE?
Do I have enough data?
Can I get more from neighbouring countries / IC datasets?
Are my data wedge-shaped?
If so, what other factors may be important?

2. The importance of validation
Toolkit methods give a range of potential boundaries
Which one do we choose?
How do we know that this will protect good ecological status?
Are there alternative sources of evidence we can use?
See Chapter 6 of Guidance Manual

3. Charophytes in Irish lakes
Relative frequency of Chara and relatives in marl lakes in Ireland
Closed circles = > G/M for macrophytes
Open circles < G/M for macrophytes
LOESS regression line
Free et al. (2016)
Biology and Environment: Proceedings of the Royal Irish Academy 116B:

4. Charophytes in Irish lakes
Values suggested by toolkit using macrophyte metric (16-30 μg/L TP)
Values suggested by analysis of Charophytes (10-15 μg/L TP

5. Charophytes in Irish lakes
Toolkit results are not necessarily wrong …
Conflict between WFD and Habitat Directive objectives
Charophytes are part of macrophyte assessment
Potential risk of circular reasoning if elements included in a BQE are used to validate boundaries set using that BQE (though not in this case)

6. Validation principles
Ideally …
look for indicators that are not included in the BQEs used to develop boundaries
Look for indicators that link to ecosystem services and which are understandable by non-specialists

7. Other possibilities: lakes
Indicator
Rationale
Arctic char (Salvelinus alpinus)
Require an oxygenated hypolimnion in which to feed.
Cyanobacterial blooms
Cyanobacteria biomass should be below the WHO low risk threshold for cyanotoxins.
Palaeoecology
Diatom-inferred TP in era before industrialisation/agricultural intensification is at or below good-status boundary.
Charophytes
Sensitive key macrophytes in high-/good- status lakes with threshold response to nutrients, indicating the position of the G/M boundary (Penning et al., 2008).

8. Other possibilities: rivers
Indicator
Rationale
Cladophora and other persistent filamentous algae
Low cover at sites with nutrient concentrations at or below good-status boundary.
Presence of salmonid fish
In rivers where salmonid fish are expected, these should be present and in good condition when nutrient concentrations are below the boundary for GES.
Evidence of fish kills
No reports of fish kills associated with night-time anoxia, when nutrient concentrations are at or below good- status thresholds.

9. Other possibilities: TRAC
Transitional and coastal waters
Palaeoecology
Diatom-inferred TN or TP in era before industrialisation/agricultural intensification is at or below good- status boundary.
All types of water body
Analysis of taxon-specific change points
Statistical technique using Threshold Indicator Taxon Analysis (TITAN).

10. If all else fails … Alternative methods to setting nutrient boundaries
Detecting change points in historical time series
Modelling
Site-specific predictions
Protecting downstream water bodies
Experimental approaches

11. Detecting change points in historical time series
Helcom (2013)
Needs long run of data
G/M as upper 95th confidence limit of oxygen debt prior to 1940

12. Detecting change points in historical time series
Could be achieved using palaeoecological data too
e.g. TP reconstructions
No direct link to BQE
Partial links to phytobenthos (diatoms) and phytoplankton

13. Modelling approaches
Various process-based models developed (e.g. Moneris)
Enable extrapolations to set targets to protect water bodies further downstream
Link with biology is often weak
e.g Germany ➜

14. Experimental approaches
Micro- / mesocosms
In situ (e.g. Bowes et al., 2012, Sci. Tot. Env. 434: )
Within-stream flow-through flumes
Ex situ (Taylor et al., 2018, J. appl. Ecol. 55: )
Recirculating channels
Different roles:
Spatial datasets / modelling
Experimental approaches
Regional / strategic planning ➜ Targeted to specific catchments