Planet WGSW-24010 User Manual page 114

_ Check that data entered onto computer are correct.
8.5 Inter pr etation of r esults
_ Use the underlying principles, 'decision trees' and standard descriptors set out in this
manual, as a guide to interpretation of MTR results.
_ Compare MTR results with relatively un-impacted reaches on the same river to indicate what
MTR scores should be achieved. Set results into a catchment context.
_ Use data from other sources to support your case.
û Do not expect the MTR to provide a measure of trophic status per se: it can only measure
change from an un-impacted site and degradation downstream of a pollution impact.
û Do not use species diversity or overall percentage macrophyte cover by themselves as
indicators of trophic status, although they may prove a useful supplementary measure in
certain circumstances.
8.6 Quality assur ance
_ Ensure that all staff involved in surveys have undergone the statutory training courses and
annual refresher courses, and that for all the macrophyte species likely to be encountered,
there is at least one member of staff who can identify them accurately.
û Do not undertaken MTR surveys unless you have attended a training course on the method
and until you have read this manual.
_ Adopt one of the two recommended audit protocols: Level 2 is the recommended minimum.
_ Carry out audits of selected sites on a random basis within 2 weeks of the primary survey.
_ Take action immediately if audit mismatch criteria are met. Discuss significant differences
between primary and audit surveys to establish the causes for differences and re-visit or re-
survey the site if necessary to confirm the reasons for the differences (or as required by the
audit protocol).
û Do not assume that the audit survey is always more correct than the original.
_ Check all results, database entries and audit survey results on a regular basis, and take
appropriate action if errors are discovered.
R&D Technical Report E38 100