1. Some technical and background
information to support
development of river health
assessment programs

2. Macroinvertebrates as ecological indcators
• Macroinvertebrates most widely used biological
indicator of stream health
– Good performance in evaluating WQ, especially heavy
metals, organic pollution
– Efficient to sample
– “Cosmopolitan” – similar groups in different parts of the world
• However:
– Less sensitive to changes in hydrology and physical form
(geomorphology)
– Do not quantify environmental “goods and services” such as
fisheries production

3. Two broad approaches
• Multi-variate approaches
– RIVPACS, AUSRIVAS
• Multi-metric approaches
– IBI, SIGNAL

4. Multi-metric indicators (e.g. IBI, SIGNAL)
1. Combine a number of metrics describing the
composition and tolerance of the invertebrate
assemblages at a site.
2. Individual or combined metric scores compared
against values derived from geographically similar
reference sites
– Multi-metric approach depends on fairly predictable
patterns of tolerance of different invertebrate taxa
(often Order/Family) to disturbance gradients

5. Multivariate indicators (e.g.
RIVPACS, AUSRIVAS)
1. Use statistical models based on reference sites to
„predict‟ biota occurring at assessment sites.
2. Difference between observed (O) and expected (E)
– (O/E) is used as „indicator.
– Predictive models replace the use of regionalisation
in deriving reference values
– Initial development requires large datasets to build
and validate statistical models
– Less transferable than multi-metric methods

6. AUSRIVAS (Australian River Assessment
System)
• Developed as “Australia-wide” river health
assessment program
– Macroinvertebrates as indicator
– Many years of development
– Au$Millions
– Still being refined
– Not used in every state.
– Not the only program of assessment.

7. Statistical models
Speces occurrence ~ env. Predictor 1 + env. Predictor 2…

8. Measuring impairment
• OE metric considers taxa predicted to occur
with a >50% probability based on site
characteristics
• OE ratio of these taxa used to assess
impairment of site

9. Multi-metric (IBI type approaches)
• SIGNAL: Stream
Invertebrate Grade
number – Average Level
• Each taxon is given a
„sensitivity‟ score (0-10)
– Reported as average score
of all taxa recorded from a
site

10. Information to calculate SIGNAL score

11. Method includes sampling
recommendations

12. Manuals provide detailed steps

13. Detailed data sheets provided for all field
assessments

14. Technical details vs implementation
• Both „multivariate‟ (e.g. AUSRIVAS) and „multi-
metric‟ scoring systems (e.g. SIGNAL, B-IBI)
used in Australia
– Both approaches shown to be effective at identifying
polluted sites.
– Approaches still being refined, especially for desert
bio-regions
Technical details of each method are
important, but both approaches effective if
properly applied

15. Chessman (2003) NSW Dept infrastructure
planning and Natural resources
“We suggest that Australia relies too heavily on bioassessment concepts developed
to assess water pollution in well-watered regions of the Northern Hemisphere.
Effective assessment of human impacts on macroinvertebrates in the rivers of inland
Australia requires a better understanding of the roles of flow regimes, including flood
and drought se- quences, and of microhabitat structure and invasive alien species.”

16. Reducing variance (s) in the results
– Training programs
– Accreditation of staff
– Web-training, data reporting etc.
– QA/QC at every stage of assessment

17. QA/QC – staff training
• Appropriate training and testing of
staff involved in field and
laboratory work
• EPA (Australia) ID 20% of
invertebrate samples twice for
consistency.
• Development of standard
operating procedures
• May involve collaboration between
organisations -
universities, research
groups, central & provincial govt.

18. AUSRIVAS: online training and accreditation

19. Summarising experiences from Australia
• River health monitoring and environmental flows
assessment strategies take considerable time to
develop, and evolve over time
• 15+ years in Australia (>20 years in USA)
– Changes in indicators
– Refinement of targets and scoring systems
• Technical details matter
• Training and QA/QC equally as important to
success of programs.