Planet WGSW-24010 User Manual page 105

Box 9 Audit pr ocedur e (.....continued)
v) difference of more than 4 in the MTR (either direction).
6. If significant differences are found then the primary surveyor and auditor meet
together to determine the reason(s) for the differences and whether they are
attributable to surveyor error.
Possible reasons for differences due to surveyor error include:
· survey relocation
· missed species
· mis-identification of species
· mis-recording of species
· errors in estimation of abundances
· mis-calculation of the MTR.
Factors other than surveyor error which may cause differences include:
· management work taking place between the two surveys
· poor survey conditions on one of the surveys
· natural changes in the macrophyte community, eg following a spate
· change in nutrient concentration in the water (with the possible exception of
species such as Cladophora, however, the flora is unlikely to respond to
nutrient changes in the short time between primary and audit surveys).
In some cases, the determination of the reason(s) may be relatively easy, for
example: mis-identification of a specimen retained in a herbarium or re-calculation
of the MTR. In other cases, it may be resolved by analysis of the sketch map and/or
a return to the site: for example, confirmation of whether a particular isolated
specimen was in the survey length or just outside; or confirmation of a dominant
and abundant macrophyte. Reference to the suffix of confidence in the survey and
to weather conditions between the two surveys should help eliminate, or otherwise,
differences being due to changes in the physical conditions of the site. In yet other
cases, however, determination of the reason(s) for the difference(s) may be
impossible. In these cases, a re-survey may be required with both surveyors in
attendance (this may be required anyway if using the Level 1 protocol). If the
dispute is about % cover estimates, a qualified third party referee may be useful.
Do not assume that the audit survey is necessarily the more correct of the two
surveys being compared. The audit only identifies differences not errors. Only
when inconsistencies are analysed by both surveyors, with a third party referee if
necessary, can it be determined where actual errors lie.
7. Action is taken according to Table 2. Note that in cases of error by the primary
surveyor, all surveys in the batch must be re-surveyed for the Level 1 protocol but
only selected (if any) re-surveys are required for the Level 2 protocol.
1.
Refer to the definition of survey in the glossary. Individual surveys are audited, not pairs/sets of surveys up-
and downstream QDs.
R&D Technical Report E38 91
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