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BCD Special Report
Historic Gardens 2010
9
patches of mud create opportunities for
specialist invertebrates and short annual
plants, which would not occur in the absence
of livestock. However, some control of
livestock is essential to prevent too much
damage to ponds. For example, exclusion of
livestock during early summer will protect
amphibians during their breeding season.
If vegetation control is necessary,
mechanical and chemical controls should be
avoided unless there is no other satisfactory
alternative. However, there are cases where
chemical control may be necessary to
control the spread of plant species listed on
Schedule 9 of the
Wildlife and Countryside
Act 1981
. A significant number of these
species are aquatic (see text box below)
and pond managers should avoid planting
these species in historic landscapes.
Many ponds in historical landscapes will
contain populations of fish. These ponds
are often devoid of amphibian populations
because of predation of larvae and at high
densities of fish the diversity of invertebrates
can also be affected. However, this is not
always the case and for ponds already
containing fish there is little ecological value
in removal unless the pond is overstocked.
However, if protected amphibians such as
great crested newts are present, then the
introduction of fish is a criminal offence
under the
Wildlife and Countryside Act 1981
and
ignorance of the presence of the newts is not a
defence; it is the landowner’s duty to find out!
When the dew pond was restored, the
mature bank-side trees were retained. The
south and the north banks have been kept
clear of trees to maintain views from the
hall and to minimise shading of open water.
Elsewhere, the bank-side trees have been
regularly pruned to maintain their shape
and keep them in a safe condition, but small
amounts of deadwood (twigs and shoots)
are allowed to fall into the pond to provide
food for the many aquatic invertebrates
that feed on decaying organic materials.
Water control structures such as silt-traps
are regularly checked to ensure that they
are still functional. To date, repairs have not
been required, but if necessary they will have
to be carried out under the supervision of
a licensed ecologist because the newts use
these structures for resting and foraging.
The rose-garden pond in 2005 supports a small breeding population of great crested newts. The pond is leaking (hence the low
water levels), but is due for restoration as part of a larger project to restore the rose-garden. The stripped and weighted plastic
bags provide newts with alternative egg-laying substrate and will be replaced with suitable plants once restoration work is
completed. A brick ramp is installed in the pond during summer to allow young amphibians to escape. (Photo: Neville Davey)
A great crested newt, captured during post-restoration
monitoring of the Brackenhurst dew pond. The distinctive
belly patterns are unique to each adult and can be used
to identify and track the fate of individuals during future
monitoring events. (Photo: Neville Davey)
damaged dew pond lining was removed
and replaced by a butyl liner and the water
control structures were repaired. All of the
work was supervised by a licensed ecologist
(a requirement of the English Nature licence)
and any animals encountered (including
the newts) were trapped and removed to
suitable habitat elsewhere in the gardens.
Photographs taken in the early 1930s
clearly showed that the pond margins
were planted with emergent reeds and
tall herbs, and that the open water areas
contained small patches of water-lily (genus
Nymphaea
) but it was not possible to
identify the actual plant species. If the pond
had been located in the parkland areas,
then native or naturalised species would
have been selected for planting. However,
given the pond’s location in the gardens,
a mix of native and ornamental species
was considered to be more appropriate.
In order to balance the requirements
of wildlife with amenity considerations,
the marginal strip of emergent vegetation
around the dew pond is restricted to a
width of less than 1.5m and submerged
and floating leaved plants do not occupy
more than 65 per cent of the open water
areas. Routine vegetation control is carried
out by hand-raking and pulling during
winter, when newts are absent. The work is
labour-intensive and often unpleasant, but
if regularly undertaken will be less intrusive
than occasional large-scale interventions.
After removal, plant materials are left next
to the pond for two to three days to allow
stranded invertebrates to return to the pond.
Parkland ponds are often effectively
managed by controlled livestock grazing
and trampling. The action of livestock
at the water’s edge fragments marginal
vegetation and creates muddy areas. Wet
Schedule 9 of the
Wildlife & Countryside Act, 1981
It is an offence without a licence, to plant or cause to grow, any plant listed on
Schedule 9. The list includes plants that may pose a threat to our native flora.
The list is revised from time to time and the current list of aquatic species is
provided below.
Water fern
Azolla filiculoides
Canadian pondweed
Elodea canadensis
Fanwort
Cabomba caroliniana
Parrot’s-feather
Myriophyllum aquaticum
Australian stonecrop
Crassula helmsii
Giant rhubarb
Gunnera tinctoria
Water hyacinth
Eichhornia crassipes
Himalayan balsam
Impatiens balsamifera
Floating pennywort
Hydrocotyle ranunculoides
Duck potato
Sagittaria latifolia
Curly waterweed
Lagarosiphon major
Water primrose
Ludwigia grandiflora
Water lettuce
Pistia stratoites
Floating water primrose
Ludwigia peploides
Nuttall’s Pondweed
Elodea nuttallii
Water primrose
Ludwigia uruguayensis