AusRivAS Protocol Development and Testing
(Project II Final Report) — WATER ECOscience Report Number 3044/2003
Dr Craig Schiller, WATER ECOscience
Department of the Environment and Heritage, 2003
ISBN 0 642 54970 2
The National River Health Program (NRHP) aims to the deliver standardised methods for the assessment of river health throughout Australia. One of the main components of the NRHP is the Monitoring River Health Initiative (MRHI) which consists of a nation-wide evaluation of the ecological condition of rivers using a set of rapid, standardised and integrated methods, known as the Australian River Assessment Scheme (AusRivAS), and a series of Toolbox projects aimed at developing and refining the set of existing assessment techniques.
This report evaluates a number of suggested improvements to the existing river health assessment protocols. The objectives of this project are to:
- formally test the effects of the recent and proposed improvements to the sampling protocol for AusRivAS on sampling quality, reliability and representativeness;
- select optimal modifications to the current sampling protocols and the final form of the sampling protocol; and
- evaluate implications of the modifications to the sampling protocol for model development and performance.
Four changes to the standard AusRivAS were evaluated:
- using visual aids during sorting;
- sorting fine and coarse fractions separately;
- using a minimum time/number of animals; and
- selecting a minimum number of chironomids.
The measures used in this study to evaluate the proposed changes to the AusRivAS protocols included:
- The similarity of taxa collected by the different protocols;
- The differences in the abundances of individual taxa collected by the different protocols;
- The similarity between the taxa collected by each protocol to be evaluated and those remaining in the residue of the standard protocol.
This study has established that none of the proposed alterations to the live-sorting procedures improves on the current standard methods. Accordingly, there is no basis for replacing the current AusRivAS live-sort protocols with one of the tested variants, as they provided no increase in efficiency or veracity of results, and the standard method appears as effective at retrieving an accurate representation of taxa at any one particular sample or site.
The study found that for both Victoria and Queensland there were no QA/QC issues for samples from clean sites, but the QA/QC performance of all live-sort protocols was unacceptable for some samples in some habitat types in turbid sites. However, the poor QA/QC performance appears related to small sample size and not the live-sort protocols per se, although other factors, including lack of homogeneity between amalgamated samples and the efficacy of the live-sort protocols in some sample types, may also be involved.
The possible direct association between small sample size and poor QA/QC performance highlights the importance of ensuring that live-sorting collects more than 100 individuals from a sample, irrespective of the sort protocol employed.
It is recommended that the current form of AusRivAS sorting protocols be accepted as the final version of the AusRivAS. However, it should be noted that problems associated with the standard protocols occur where less than 100 animals are collected from a sample, at least for certain habitat types in turbid conditions. This has serious implications for AusRivAS assessments of river health and warrants further investigation. Further studies are also recommended to discern the problems concerning the QA/QC performance of individual samples in turbid habitats.