Fen Management Handbook - Scottish Natural Heritage

There is usually some degree of subjectivity inherent in the evaluation process. In general, however,
the following list should be considered when drawing up a list of features:
– Species with legally protected status (Conservation Regulations, Wildlife & Countryside Act).
– UKBAP Priority Species
– LBAP species
– Rarity criteria (Nationally Notable, Red Lists, BoCC etc.)
– Significant population thresholds (e.g. 1% of population at a range of spatial scales)
– Species scoring systems for assemblages (e.g. SSSI selection criteria for bird assemblages)
– Evaluation criteria for EcIA – National, Regional etc
– ‘Flagship’ species
– Species of local interest
In general, it will be normal to prioritise species of nature conservation concern i.e. UKBAP species
and/or species assemblages of note (see Appendix 1). Note that for invertebrates, statuses need
careful interpretation. UKBAP status is of real significance only if the species is habitat restricted and
listed because of loss or decline in quality of fen habitat. Many invertebrate groups were assessed
for Red Data Book and Nationally Scarce status some time ago, and many species have since
changed in status, or become more widely known through increased recording; there is at best an
approximate relationship between the formal conservation status of most invertebrates and reality,
and an estimate needs to be made of the current actual status of each species with formal status
before any assessment or management decisions are based on it. The advice of an invertebrate
specialist should be sought to make such a judgement; otherwise one should assume that formal
conservation status is deserved and the species should be prioritised accordingly.
Habitat management requirements for invertebrates
Additional considerations for invertebrate habitat management regimes are:
Litter piles from cutting are useful as habitat, especially as hibernation sites; substantial piles rising
well above highest water levels are preferable.
Complex small-scale structure may be easier to maintain in a grazed habitat than one managed by
cutting/clearing; but more prone to unplanned change.
As a general rule one should aim for constancy, and make change as gradual and small-scale as
possible. Avoid sudden changes in density of grazing animals, and never put on a large number of
grazers to renovate a site in the early stages of management.
Be tolerant of some scrub representation on ‘open’ habitat, including carr.
Veteran trees and large timber lying on the ground can support special faunas.
The table below describes broad management requirements for some legally protected invertebrate
species. It does not include all the protected species previously identified as potentially associated
with fens: there are no currently known fen populations of mole cricket, so it would be premature to
suggest its management requirements, and White-clawed crayfish is not considered a fen species,
merely a potential associate.
318