rivers intercalibration phase 2 key cross-gig activities 2008-2011 refining reference conditions ...

Rivers Intercalibration Phase 2Key Cross-GIG activities 2008-2011

Refining Reference Conditions Intercalibrating Large River Ecological Status

Initial scoping meeting Lyon May 2008

Roger Owen

Jean-Gabriel Wasson

John Murray-Bligh

Reference conditionsWe need to:

Stabilise the concepts Harmonise the criteria (QE, GIGs) Quantify the thresholds : search for

"no effect" thresholds

Produce a common procedure

Intercalibration Phase 2 2008-2011: Rivers

Reference conditions : the present situation

Mix of quantitative criteria and "qualitative" evaluation

Mix of:Driving forces (land cover), Pressures (dams, effluents)Stressors (chemical parameters)

Is the relationship maintained in different human and natural contexts ?

Reference Thresholds based on expert judgement What underlying concepts ? Data ?Same criteria for all QE ? all types ?


Pressure - response relationship

• The relationship between the driving forces and the biological response is dependent upon the natural and human context

• The relationship between the driving forces and the biological response is dependent upon the natural and human context

Driving forces (Agricultural land cover)


FRANCE


NORWAY


Pressures - responses relationships

In this case, a very low biological impact can be observed with a medium level of pressures.In this case, a very low biological impact can be observed with a medium level of pressures.


Consequences for reference criteria (1)

The relationship between agricultural land cover and biological impact is highly dependent of the structure of the landscape

The relationship is poorly predictive, and cannot be easily extrapolated Can be used as a first "filter" to select "candidate" REF sites

The relationship with artificial/urban land cover is much more reliable (REBECCA results). Can be a valid reference criterion



A very low level of pressures corresponds always to a very low biological impact : valid reference criteria. The reverse is not always true : a very low biological impact

can be encountered also with a medium level of pressures

We should not reject all the sites with a low to medium level of pressures The validation must be done at the "stressors" level (i.e.

abiotic parameters)

This supports the GIG's practical approach based on "reference" and "rejection" threshold This could apply also to the Urban land- cover indicator



The relationships between the "stressors" (i.e. abiotic parameters) and the biology is NOT dependent upon the human context.

Can we find the threshold corresponding to the beginning of the biological impact : "no-impact threshold“?

But it can vary according to the natural typology.


No-impact threshold : myth or reality ?

Etat BiologiqueEQR

PressionAnthropique?

??

What happens

here ?


No-impact threshold : is there a conceptual model ?

About 100 experts..Allan, Barbour, Cormier, Gerritsen, Hawkins,Hughues, Karr, Larsen, Mc Cormick, Mc Intyre, Rankin, Wang, Yoder…

About 100 experts..Allan, Barbour, Cormier, Gerritsen, Hawkins,Hughues, Karr, Larsen, Mc Cormick, Mc Intyre, Rankin, Wang, Yoder…


Bio

logi

cal C

ond

itio

n

Increasing Effect of Disturbance[Stressor gradient]

Low High

1Native or natural condition

2 Minimal loss of species; some density changes may occur

3Some replacement of sensitive-rare species; functions fully maintained 4

Some sensitive species maintained; altered distributions; functions largely maintained

5

6

Tolerant species show increasing dominance; sensitive species are rare; functions altered Severe alteration of

structure and function

Natural

Degraded


No impact threshold

• ICMi vs BOD5

• All CB types, France

0

0,02

0,04

0,06

0,08

0,1

0,12

0,14

total 5 4,75 4,5 4,25 4 3,8 3,75

pvalueRsquared


Large rivers - Main issues Deep rivers in scope (non-wadeable)? Reference values

Almost no large rivers exist in reference condition (>5000 Km2?)

IC typology limited to rivers <10,000 Km2 and reference values probably not applicable

Sampling methods Shallow water sampling methods are

inappropriate for deep waters (non-wading depth)

Survey/sampling costs could be high


Defining reference valuesConsider heavily modified and natural rivers

Check reference screening criteria for large rivers

Investigate alternative approaches for defining reference values/EQRs:Option: Define the G/M boundary based on

physico-chemistry and hydromorphology then biological community


Large Rivers Typology

Can we define realistic reference values for EQRs (new typology?)

IC Phase 1: Some MS included deep rivers in intercalibration of RC-5 (large lowland rivers on mixed geology, 1000-10000 km2).

Are reference values for shallow water samples appropriate for deep water methods for any BQE?


Loss of sinuosity (from historical reference)

Coûtécologique

SinuositéSinuosité 0

1

2

3

4

5

6

7

8

9

10

1 1,1 1,2 1,3 1,4 1,5 1,6 1,7 1,8 1,9 2

²Y =

Coû

t éco

logi

que

a b

²Y a = 1

²Y b = 9 Coefficient I1

H/G Boundary

Reference

From Wasson et al. 1998


Sampling

Sampling large rivers can be expensive

Consider use of other information to supplement biological data

e.g. measure of lateral freedom space in river types that should have multiple channels


Sampling

Investigate sampling methods for deep and large rivers

Identify the biological communities that best reflect the ecological quality of large rivers Fish (already done in Fish IC?) Invertebrates Phytobenthos & diatoms Others: (eg.Riparian vegetation?)


Proposed working strategy River Steering Group provides a unified approach across all

GIGs and biological quality elements (also communicate with lakes GIGs)

Intercalibration of large rivers will be undertaken by existing BQE groups of experts working across GIGs

First step are 2 papers with outline proposals (Nov 08); also a questionnaire to collect information about existing data and methods for all BQEs from all river GIGs – (ready now)

All river GIG meeting to agree detailed work programme Spring 2009

rivers intercalibration phase 2 key cross-gig activities 2008-2011 refining reference conditions ...

Documents

yoderintercalibration

low biological impact

rivers intercalibration

valid reference criteria

reference thresholds

low level of pressures

riversnoimpact threshold

criteria qe