To identify the sorting and identification errors associated with each Member States processing of macroinvertebrate and diatom samples. To complement the results Workpackage 8 and to provide an integrated appraisal of the impact of uncertainty upon the assignment of grades of Ecological Status.
Both macroinvertebrate and diatom samples will be audited. A single consortium member will act as auditors for all samples of a particular taxonomic group, except that samples processed by that consortium member will be audited by another Member State.
The auditors will be:
Audit of macroinvertebrate samples: The audit of macroinvertebrate samples will be based on the well-tested principles and procedures adopted in the United Kingdom since 1990. The following description summarises the detailed and prescriptive protocols operated in practice.
Each consortium member will sort and identify samples according to the appropriate protocol for the procedures used for sampling (e.g. AQEM, RIVPACS). All original organic and inorganic material comprising the sorted sample, including any animals not removed during the sorting process, will be retained, returned to a storage vessel, labelled and represerved.
Specimens removed from the sample will be identified to the species level wherever. Identified specimens will retained in a small labelled vial stored within the reconstituted sample. A list of the taxa present in each sample and their abundances will be recorded for each sample. The laboratory undertaking the primary sampling process will supply the auditors with copies of all taxon lists for individual samples. The auditor will also be supplied with all individual vials containing the sorted and identified taxa from the samples.
The auditor will select the samples to be processed using an agreed format of random selection. A minimum of 20 samples per consortium laboratory, or 10% of that laboratory's processed samples, whichever is the larger, will be audited. The reconstituted samples selected for audit will be dispatched to the auditor and auditing will be undertaken. Auditing will include resorting of the audited samples and reidentification of the animals removed by the original laboratory. The revised taxon lists derived by the auditors will be compared with that supplied by the original laboratory. Both sorting and identification errors will be combined to determine the overall error rates associated with each laboratory and each international and national macroinvertebrate protocol.
Taxonomic knowledge and the availability of suitable species level keys vary from country to country. Therefore, audit will initially be at family level, in order to provide consistent data for all participating Member States. A subset of samples from Member States with well known and well keyed macroinvertebrate species will be further audited at species level in order to define the relationship between the rate of family and species level data and the significance of this for national assessment protocols.
Inadequacies in the knowledge of certain groups of macroinvertebrates in certain countries will be documented and recommendations for filling these gaps will be produced.
Auditing of diatom samples will follow the same procedures except that the identification of specimens requires that they be mounted on microscope slides. All slides produced will be supplied to the auditors for scrutiny. Both the identity and abundance of specimens will be checked by the auditing process. Error rates will be determined by comparison of the auditor's taxon lists and abundances with those of the original laboratory.
Identification will be to the level necessary to apply the TDI (Trophic Diatom Index) metric. Individual Member States may compare the error rates detected by the auditors with each of these two major taxonomic groups with those errors detected by their national audit protocols. This will be achieved by their independent funding sources but any available data will integrated in the STAR programme under Workpackages 11, 12 and 14.
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