While these data represent the most comprehensive account of
the condition of sites designated for nature conservation in the
United Kingdom yet produced, a number of provisos need to be
made.
Because the guidance on feature objectives was made available
progressively during the six-year monitoring period, not all
assessments were made against objectives formulated in accordance
with this guidance. This issue will reduce in significance as
the monitoring programme is rolled forward.
Ideally results would be presented both by numbers of features
and by area of features. This would allow biases caused by
large numbers of small features (such as tend to occur in the
lowlands), or a few large features (the corollary in the uplands),
to be avoided. Unfortunately, it is not possible at the
current time to present data by area of feature, and all the graphs
presented are therefore for numbers of features.
The four statutory nature conservation agencies carrying out
the monitoring undertook this work in a manner determined by
priorities in their various countries. For example, the
Countryside Council for Wales (CCW) concentrated their effort on
SACs, plus some assessments on SPAs. The reports
from English Nature (now Known as Natural England)concentrated on
habitat SSSIs and SACs; there are fewer reports relating to
features on species SSSIs and few reports on SPA or Ramsar
features. Such discrepancies between countries can be
expected to reduce as the monitoring programme is rolled
forward.
If a feature is reported in unfavourable condition it does not
mean that the whole of that feature is degraded. The nature
of the assessments made, and the use of several attributes for each
feature, means that it may have failed on one attribute rather than
several, and may have done so by a small margin rather than a large
one. It is important, therefore, to understand that the
threshold for unfavourable condition is set within guidelines on a
site by site basis. This is essential to ensure that site
management is focussed on the local circumstances in which a
feature is found.
Quality assurance of procedures was undertaken by the
individual nature conservation agencies in accordance with
processes determined by the agency concerned. Further quality
assurance to ensure comparability of assessments within and between
agencies will be introduced shortly.
It is possible that the method treats SAC features more
severely than SSSI features. SACs tend to be larger than
SSSIs and are often an aggregation of SSSIs. Aggregation
rules for data mean that parts of a feature assessed as
unfavourable can cause the whole feature to be assessed as
unfavourable. This is more likely to happen on aggregated or
large sites. Another factor maybe that SAC features are
selected because they are particularly in need of conservation
across Europe. In addition, SAC features tend to be defined
more tightly than A/SSSI features and therefore targets are set
more precisely.