Alan Hildrew Martin Pusch Klement Tockner Intercalibration of rivers and lakes Alan Hildrew Martin Pusch Klement Tockner

The challenge to the reviewers Dense, complicated and long! Statistical conjuring tricks! Variety of approaches Realism and idealism

The hard question - has it worked? Yes and no! For rivers: As presently feasible, intercalibration has been achieved for: Macroinverts, C-B, N, Alpine, Medit., E-C…..but not for large rivers etc Phytobenthos, N and Alpine….but not for C-B or Medit. (but for ‘good reasons’)

Problems (with a rivers bias) A network of intercalibration sites - none emerged Reference conditions Information on pressures Typology

The circularity in setting reference conditions Northern GIG (phytobenthos) - “the use of the biota to define reference conditions - is not encouraged as the ND define ecological status in relation to the biota expected under undisturbed conditions…and the use of land-use and pressure data to define ‘undisturbed conditions’ ensures rigour and objectivity in the definition of the expected value” i.e. the means used to define the environmental pressure and the ecological response must be independent. We were not convinced this was always the case.

There are no reference sites “The EC GIG agreed to follow an alternative approach to resolve these issues by defining IC type specific , harmonised quality criteria. In general, the GIG set common high-good (type RE1) and good-moderate (types R-E2-4) quality class boundaries for the national assessment methods using existing data assembled within the EC GIG calibration exercise. The main idea….is to overcome the lack of (near natural) references by defining alternative references.”

The value of large rivers availability of reference sites Value 1 2 3 4……………………..n Stream order

Intercalibration - reference conditions were not consistent among MS Central-Baltic (phytobenthos) - “There was considerable variation in the values of four metric computed at reference sites between MS. It is not clear…whether these differences are due to underlying differences in the unimpacted state between MS or whether they reflect failures to screen data adequately” Northern (phytobenthos) - “The challenge is to differentiate between those differences in national reference states that reflect genuine biogeographical variability across the GIG and those that reflect differences in approach by those responsible for implementation”

There are not enough pressure data Mediterranean GIG (macroinverts) - “Due to the lack of data…, the occasional use of expert judgement was an accepted means of validating reference sites especially in interpreting the use of different forms of chemical determinants throughout the GIG. A central pressures database was not available to verify reference sites.”

Problems with typology

Problems with typology Central Baltic (phytobenthos) - “Overall, these date suggest that the IC typology has no meaning for phytobenthos and subsequent analyses analyses ignore the IC types”

Problems with typology Northern GIG (phytobenthos) - “this river typology was derived primarily for the macroinvertebrate intercalibration ……common intercalibration river types for the CB-GIG..did not distinguish between diatom assemblages…(and therefore)..the N-GIG working group agreed that a ‘no types’ approach was fit for purpose” Shouldn’t ‘types’ be consistent among biological quality elements?

Problems with typology Central-Baltic (macroinverts) - “A number of issues underlined the recommended use of the ‘all types combined’ option….. Variation in MS IC river type boundary values attributable to differences in IC typology (that) cannot be quantified Type specific variation within each IC river type… The range of variability between MS boundary values is greater than the variability between river types…

Problems with typology “….the whole concept of compartmentalising communities into a number of distinct types is fundamentally flawed, and that the overwhelming body of evidence (and theoretical arguments) suggests there is normally a gradual adjustment of species composition along environmental gradients. Nevertheless, the use of community ‘types’ persists as an integral part of many monitoring systems across Europe and we fear it will significantly limit our understanding of ecosystems and hence our ability to detect degradation.” (Woodward, Friberg & Hildrew, in press)

Problems with typology

Classifying a continuum…..

The future Uncertainty

Incorporating uncertainty (Jones et al. in press) Probability of miscalculation SE of estimate as % of band width

The future Functional indices Independent of biogeography Species traits Ecosystem processes Independent of biogeography Easier to reconstruct reference conditions Incorporate new understanding/science

The future Intercalibration sites “..an excellent step..establish a number of key catchments across Europe…sites with background data..and where ‘reference conditions’ could be objectively defined…include facilities for manipulative or statistical experiments at large scales. Against such reference sites, gradients of human pressures would enable us to determine reductions in ecological status -” AND TO INTERCALIBRATE EXISTING AND NEW MONITORING TECHNIQUES

The “LOCAR” catchments

An impressive body of work Intercalibration of rivers and lakes Good progress An impressive body of work An ongoing process Direct calibration at key sites