The following is taken directly from "Wetlands, Industry
and Wildlife - a manual of principles and practice" with the kind
permission of The Wildfowl & Wetlands Trust. (Chapter
3 - Deciding what to do).
"[The stage after investigation] is to evaluate the site. What,
for instance, is the significance of the wildlife that has been found using the site?
Species and habitats which are rare in a local, regional or national context need to be
identified.
The implications of the various potential constraints that have come to
light also need to be considered. What, for instance, is the potential of the site for
attracting wildlife? Such questions need to be given careful consideration before any
proposals are pursued. The following paragraphs outline some of the factors that
can have a great bearing on wetland creation and enhancement, but which are all too often
given insufficient consideration.
1) The physical and chemical
environment. Assessment of the soils, water supply, hydrology
and water quality will be necessary in order to determine:
a) the ease with which areas of wetland can be created on a site;
b) the nutrient levels likely to be found in a wetland;
c) other characteristics, such as salinity, of the water.
This information will indicate what wildlife a wetland is likely to
support and/or what measures might be required to make the water quality and regime
suitable for a particular group of wildlife. See Chapter 5 (Chapter
5 - Water: chemistry and quality).
2) Geographical location. Perhaps not surprisingly, all conservation objectives are not applicable to all
parts of the UK. For example, the species assemblages associated with wetlands in
northwest Scotland, such as bog pools, are significantly different from comparable
habitats in southeast England. One should, therefore, expect different management
objectives for this habitat in these two locations. While some species may be absent from
an area simply because of lack of suitable habitat, the distribution of many species is
dictated by climate and/or their dispersal ability. It is, therefore, important to
consider the location of a particular site and the species that realistically could occur
there.
An industrial example is provided by the sugar factories at Allscott in
Shropshire and Cantley in Norfolk which both employ large areas of lagoons with reedbeds.
Cantley regularly attracts nesting Bearded Tits and hunting Marsh Harriers, owing to the
fact that it lies within the main breeding range for these species. By contrast, the most
important reedbed bird species found at Allscott is the far more ubiquitous Reed Warbler.
In nature conservation terms the reedbeds at Cantley are, therefore, of greater
significance than those at Allscott owing, ultimately, to their location.
3) Proximity to other sites and
habitats. There are a number of questions that should be
answered when considering a site in the context of both its immediate and local areas.
a) Is the local area of importance for a particular
wetland community or species? If so, is it possible to accommodate this interest
on the site and, therefore, strengthen that local value? The closer two similar habitats
are to one another, the greater the likelihood of species colonising from one to the
other.
b) Are there adjoining habitats of particular conservation value?
Is it possible to use the site to enhance this value? In general, the larger the area of a
particular habitat, the more likely it is to support specialist species associated with
that habitat, and the more viable the populations of a particular species are likely to
be. It may therefore be appropriate to encourage the important habitat to spread, or to
encourage habitats that are complementary to that habitat, including non-wetland habitats
such as woodland or grassland.
c) Does the surrounding area offer habitats that complement those on or
proposed for the site? Many largely aquatic animals are dependent upon, or at
least influenced by, the adjacent terrestrial habitats: scrub provides perches and shelter
from the wind for flying insects; newts feed in long grass and hibernate under soil
or stones; Wigeon and Coot graze on areas of short grass adjacent to open water. If a site
is surrounded by extensive undeveloped land it may be helpful to consider how this can be
used in the design of any new wildlife features.
d) Is it possible to link areas of similar habitat together?
Corridors along which animals and plants can migrate are extremely valuable. Streams and
ditches offer suitable corridors for many species of wetland wildlife.
4) The size of the wetlands. The size of a wetland is one factor determining the number and range of species
which potentially can be accommodated. All species require a minimum area of suitable
habitat in order to sustain a viable population. Although such minimum areas have rarely
been set down, it is none the less possible to say in broad terms what types of wildlife
might be found in what size wetlands Isolated ponds of less than 0.5 ha, for example, can
provide valuable habitat for dragonflies and amphibians. By contrast, such ponds attract a
very limited range of waterbirds, few of which are likely to breed there. In order to
maximise the conservation value of such ponds, it will normally be more appropriate to
design and manage them for amphibians and dragonflies rather than waterbirds. All too
often people try to accommodate too many species within a nature area. Few sites are large
enough to justify targeting a wide cross-section of wildlife; it is far better to design a
wetland around a realistic community rather than a maximum variety.
5) Presence of notable species. Normally, priority should be given to retaining sufficient suitable habitat to
support any notable species already present on a site, before attempting to encourage
further species. If a species has already been recorded, there is a good chance that the
site is already suitable for it. The restoration scheme for the land adjacent to Little
Bradley Pond (see Feature 16.4 (Chapter
16 - Reclaiming industrial land)),
for example, made a priority of creating further habitat for the existing exceptional
dragonfly community, rather than trying to encourage additional species. If there is the
opportunity to create wetlands that are likely to be colonised by rare or threatened
species, provided they are appropriate to the area, this is preferable to producing a
general wetland that is likely to be colonised only by common species. This does not
necessarily mean creating a wilderness; the unusual properties of some industrial wastes
such as PFA occasionally provide opportunities for rare plants (see 13.2.4 (Chapter
13 - Ash (PFA) storage)). A
company will gain greater credibility and publicity where it makes a real contribution to
nature conservation by, for instance, encouraging threatened wildlife.
6) The ability to manage a site. It is most important to make an assessment of the resources available to manage a
site. There is little point in prescribing a superb wetland if its interest will depend
upon a level of management that is never likely to be achieved. In general, aim to make
management as simple as possible (see 8.6 (Chapter
8 - Other aspects of wetland design)). Clarify who is likely to carry out the work and how much they can
realistically achieve. In some cases it will be possible to achieve the necessary
management for wildlife simply by manipulating an existing maintenance regime, e.g.
adjusting the grass mowing cycle. The ease with which management can be carried out will
be influenced by the access to the site (is it, for instance, possible to use a tractor to
carry out all the mowing?) and the range of tools and equipment that is available. It is a
common misconception that there are many people available to manage a site on a voluntary
basis; the truth is that it requires a dedicated, trained individual or group to develop
and maintain a successful volunteer workforce.
7) Operational constraints. Industrial operations can have a major bearing on the wildlife that can
realistically be attracted to a wetland. How, for instance, do industrial processes affect
the supply and quality of water available? The sugar manufacturing process, for example,
is highly seasonal, and this largely dictates the amount of water to be found in the
treatment lagoons at a particular time of year. Operational activities may also have
indirect effects; noisy processes, both on and adjacent to a site, may make parts of that
site unsuitable for attracting certain birds and mammals. Any objectives and proposals for
wildlife must recognise such constraints.
8) Legal constraints. There
are various pieces of legislation which could influence the design and/or functioning of a
wetland. The following list highlights some aspects that will need consideration and
consultation with outside bodies. If at all possible it is best to discuss initial ideas
informally before investing time in drawing up detailed plans.
a) Reservoirs Act. Wetlands contained by dams
or embankments may require a licence under this Act. NRA can give guidance.
b) Discharge Consent. If a new wetland is allowed to drain into an
existing watercourse then consent will be required from the NRA.
c) Drainage Consent. If any works are likely to affect drainage in
the local area, then consent will again be required from the NRA.
d) Health & Safety regulations. These will influence who can legally
carry out the required management; for instance, herbicides must only be used by
contractors holding the relevant certificates. There may also be implications for allowing
visitors onto a site and the safeguards that need to be implemented.
e) Planning regulations. It is always sensible to discuss proposals with
the local planning authority. New buildings and certain changes in land-use will require
planning permission.
f) The Wildlife and Countryside Act. The Act provides most of our
wildlife legislation, parts of which may be relevant to site development or management.
For example, plants can only be uprooted with the permission of the landowner and a
licence is required to move or handle various protected species. It is illegal to disturb
most nesting birds, and schedules for major works should be arranged accordingly. Further
information about the Act should be obtained from the statutory conservation agencies (see
Appendix 10 (Appendix
10 - Addresses of relevant organisations)).
9) Accommodating the public. A company will gain PR benefits if it can demonstrate to the public that it
is actively encouraging wildlife. Whether, and to what extent, the public can be allowed
on a site will in part be influenced by its location and layout. If, for instance, a site
is very remote there may be little demand for such facilities. Where a road or public
footpath skirts a site, relatively little work might be required to provide public access
(see 8.4 (Chapter
8 - Other aspects of wetland design))."
(B93) |
