Summary of a Local Biodiversity Action Plan for the Great Crested Newt
Issue and rationale
Great Crested Newts are becoming scarcer, mostly as a result of loss of their habitat,
and not only
in Britain but in the rest of Europe too. This is why they have been protected by law under the
Wildlife and Countryside Act 1981, and the EU’s Habitats and Species Directive.
Great Crested Newts need several different types of habitat during their lives. But
to breed, the one
thing they cannot do without is water- typically fair-sized ponds, often in chalky or clay soils,
sometimes in gardens or small reservoirs , flooded marl pits, brick pits, or even very slow-moving
canals or ditches. Usually these are more than 100 square metres in area and over 50 cm deep
with a fair amount of water plants growing in them.
Newts disperse over land to forage, find shelter and to move between ponds. Great
Crested Newts
need at least half a hectare of tussocky grassland contiguous to the pond for foraging and shelter.
In October and November, as temperatures start to fall, Great Crested Newts hibernate,
usually on
land, and sometimes in groups. They choose a sheltered, damp, frost free nook, sometimes
underground. In the Spring they emerge to start the a new life cycle.
The presence of routes for dispersal to adjacent ponds is an important factor in maintaining
population stability in a particular area.
They tend to lay their eggs in the same pond in which they were hatched. Fish eat
their eggs and
tadpoles, and ducks eat waterweed they need for cover and egg-laying, and may even eat tadpoles.
Great Crested Newts are not common in ponds inhabited by fish and waterfowl.
Finally, there is the issue of public disturbance, either of the fresh water habitat
or the adjacent
land.
Managing a population of Great Crested Newts requires addressing the above fundamental
issues,
which are focused firmly on its habitat requirements.
Refs Facts about great crested newts (English Nature): Great Crested
Newt Conservation
Handbook (Froglife)
CMS Objective
To maintain the Great Crested Newt in a favourable condition where the measurable
attribute of the
population is the mean of 6 counts of individuals per year falls. The target is to maintain this
attribute within the range of 150-250 individuals per ha of foraging habitat.
CMS Attribute
The number of individuals counted in bottle traps, torchlight searches, or netting
activities.
CMS Management factors
Pond Factors
Area/depth
Decisions about
the depth and overall shape of new ponds will be influenced by
the purpose for which the pond is being built. For example, dew ponds that are
also to be used as a livestock drinking supply may be shallower than those on
heavy clay soils in arable farmland. The size of a permanent pond (i.e. one that
does not or very rarely dries out) will influence both its capacity to sustain adult
newts throughout the year and the number of young that can be produced.
In deeper, larger
ponds, the water is more buffered from cold air cooling or freezing
the upper layers of water than in shallow ponds, especially in spring and autumn.
Temperature influences newt metabolism; ponds in excess of one metre depth are
most likely to maintain water temperatures at the bottom that are high enough for
newt activity throughout the year. Ponds of less than about 25 square metres
surface area tend to have insufficient depth and volume to allow many great
crested newt larvae to survive. This may be because of competition, with larvae
preying on each other, and bottom dwelling predators being able to find them more
easily. Small ponds that are 'topped up' or that receive water from natural sources
in late summer may have a better prospect of recruiting young than those that
progressively dry out. In conditions where the water table fluctuates greatly,
occasional drying out may sometimes favour newts in the long run, as this can
result in a large drop in predator numbers, especially fish.
Predicting the variation
in pond water levels may require prior survey and testing so
that the likely result of high rainfall, and of dry or drought conditions is understood.
Altering the profile of a pond after construction may be difficult, although
inlet/outlet pipes or ditches can be adjusted.
Water quality
Newts are found
in aquatic habitats consisting of clear water with a pH range
between slightly below to slightly above neutral.
Like all amphibians,
great crested newts have a permeable skin, and are at risk
from any chemicals they may encounter. With this in mind, it is recommended
that a precautionary approach to exposing newts to chemicals (e.g. landfill
leachate, fertilisers and herbicides) is adopted. This means avoid the use of, or
prevent access by newts to chemicals wherever possible. Those chemicals that
break down quickly to harmless substances are preferred when use is required.
Where pernicious weeds are a problem in terrestrial habitat, or invasive or alien
water plants are threatening a breeding pond, mechanical control where
practicable is always recommended before considering the use of herbicide.
Careful treatment of invasive vegetation with approved chemicals may be
considered in some limited situations, although success is not guaranteed. Use of
chemicals almost always requires a consent and/or licence if the waterbody is
connected to groundwater and/or has an inflow and outflow (where it is required by
EA or SEPA) or if it has some informal or formal level of site designation (e.g. Site
of Special Scientific Interest (SSSI).
Open water
When deciding on
appropriate management of vegetation in and around a
waterbody, it is important to have a clear idea of the end result that you are hoping
to achieve. The more survey data you have available, the better informed your
decisions will be. The shadier a pond is, the lower the water temperature is likely
to be throughout much of the year. A pond surrounded by overhanging trees will
not let summer sunlight penetrate to the water surface, and therefore it will not be
warmed. In addition, overhanging vegetation will shed dead material into the water,
accelerating the build up of nutrients and probably leading to a requirement for
more frequent de-silting. On the other hand, trees and scrub near the pond can
provide good terrestrial habitat for wildlife species, including great crested newts. A
compromise could involve retaining tree and scrub vegetation on the north side of a
pond where it will cast little or no shade on the water surface, and removing
shading vegetation on at least the south side.
Bank profile
Marginal and emergent
vegetation are important components of a great crested
newt pond as they provide excellent egg-laying sites. Good plants for this purpose
include water forget-me-not Myosotis scorpioides, flote/sweet grass Glycerin
fluitans and great hairy willowherb Epilobium hirsutum. Marginals and emergents
are also important habitat for other species groups, notably damselflies,
dragonfiies, water voles and birds. They are, however, an integral part of the natural
successional change of a waterbody to a marshy area, and finally dry land.
Therefore whilst it is preferable to have a good range and area of marginal plants, if
they have reached the stage where they extend across the entire water surface, it
may be time to consider their partial removal. In most circumstances it will be
desirable to retain a fringe of marginal and emergent vegetation around at least half
of a pond's edge. Where the marginal vegetation is particularly invasive, and
provides no specific benefit to crested newts, it may be decided that its complete
removal is necessary. This could be argued for greater reedmace Typha latifolia in
small, shallow ponds, for example.
Diversity of submerged
vegetation
Submerged vegetation
is an important component of the pond ecosystem, making
it habitable to a wide range of animals. Too many plants can occasionally be
undesirable for newts however, if the water column becomes completely shaded
and choked. Pioneer (early successional) submerged vegetation
like
stoneworts (e.g. Chara spp.) is unlikely to cause a problem. In time, stoneworts
are normally replaced by higher plants like curled pondweed Potamogeton
crispus or water crowfoot Ranunculus aquatilis. Introduced or 'alien'
submerged plants can grow very vigorously and dominate more beneficial native
species. New Zealand stonecrop Crassula helmsii and Canadian pondweed
Elodea canadensis are two examples to be avoided. In ; most instances the
complete removal of such species is j recommended. The autumn/winter die-off
of large amounts of | submerged plant material (e.g.
hornwort Ceratophyllimi
demenum) can sometimes lead to temporary pond stagnation.; Raking out pond
weed may help to prevent stagnation and slow j the process of natural succession.
Fish
The introduction
of fish to a pond can be so detrimental that their total removal is
essential to protect any great crested newt population present. The selection and
careful application of appropriate methods and timing for fish removal are important
in order to minimise the impact of work on pond wildlife. All methods offish removal
are subject to licensing and/or consents.
Netting
Netting is usually
done with the lowering of water levels, using a pump or siphon.
Netting alone will not usually remove the entire fish population; it will only be a
temporary measure and fish stocks may recover in a few years. Netting may be
combined with additional methods offish removal like electrofishing or the
application of a chemical narcotising solution. Aquatic plant life dies back in
winter, making netting easier, although fish tend to move towards the bottom of
ponds in cold weather. Consideration should also be given to fish breeding
seasons. Sticklebacks for example place fertilised eggs in nests that cannot
easily be located between March and October.
A small former farm
pond in a rural town garden is netted to remove large numbers
of recently introduced carp from a great crested newt breeding pond
The netted fish
are removed. The adult newt in the catch is released back to the
pond
Draining down
Draining down and
drying out a pond is the only way to guarantee total fish
removal but it can cause massive disruption and local extinction of plant and
invertebrate life, especially if the pond base is left to dry out to ensure that small
fish fry (and egg nests of sticklebacks) are no longer present. Pond bases may be
uneven, causing fish to be trapped in pockets of water or silt, sometimes in the
middle of ponds and without easy access for netting. Fish are most easily
removed from those ponds that are not heavily vegetated and that readily drain to a
single point at the pond edge.
Electrofishing
This method does
not require the complete draining of a pond, but does require an
experienced team of trained workers, a boat and specialised equipment.
Electrofishing tends to stun fish over 120mm total length, leaving most smaller fish
unaffected.
Chemical culling
Where draining is
not practical or poses unacceptable risks to wildlife the removal
of sticklebacks and the young of other small fish may only be achieved with the
authorised use of a piscicide. Rotenone is a biodegradable, non-residual, and
naturally occurring chemical that, diluted in pond water, immobilises fish causing
them to float to the surface where they may be netted. Permissions and consents
for the use of rotenone are necessary, and the relevant Agency (EA or SEERAD)
should be consulted, as regulations governing their use are under constant review.
Piscicide use is managed by the Control of Pesticides Regulations (1986). The
use of noxious substances for the use of taking or destroying fish is regulated
under Section 2 of The Salmon and Freshwater Fisheries Act (1975) and is
managed by the Environment Agency in England and Wales and SEERAD (see
next page) in Scotland. Consultation with and an application to the local area
consenting officer is needed. However, rotenone is approved only as an insecticide
by the Pesticide Safety Directorate so approval for use on fish will not be given
other than in exceptional cases, with rigorous checks to show there is no
alternative and that the work is essential. Where great crested newts are present,
the relevant SNCO should also be consulted.
Use of chemicals
requires stringent planning, trained operators and careful
monitoring. It may not be allowed at some locations
Waterfowl
Waterfowl are sometimes
advantageous in bringing new colonisers, in the form of
fertilized eggs and tadpoles that are inadvertently become attached to their
webbed feet. But a resident population of ducks on a small pond can devastate a
newt population. Waterfowl are best excluded from a newt reserve.
Foraging habitat factors
Area
Terrestrial (or
land) habitat around a pond provides feeding and sheltering places
for newts when they are out of water. The type of habitat around a pond will
influence the movement of newts and their long distance dispersal.
Dense, heavily structured
habitats (like scrub), provide many places where newts
can overwinter and take refuge from desiccation or bad weather. Rough grassland
with dense tussocks will also provide areas with food and cover.
Great crested newt
densities have been measured at a range of sites. They have
rarely been found to exceed 400 adult newts per hectare, but 100-300 per hectare
is perhaps more typical. A small pond may need at least half a hectare of suitable
habitat around it to support a viable population of great crested newts. Newt
numbers may be greatly reduced and the population left vulnerable to local
extinction when the amount of land habitat is too small or when connections to
other ponds are lost. The ratio of water to good quality land habitat for optimum
newt numbers is not known, but a 1:20 ratio may not be excessive. On this basis,
a pond with a 20 metre span will be supported by a little over one hectare of good
quality land habitat. A ten hectare habitat creation area might support between five
and ten ponds of such a size.
Vegetation
Newly created and
enhanced land habitats will take time to mature and become
valuable for newts, although a lot can be achieved in a single year, if planting
seasons are carefully observed. For bare sites such as reversion from agriculture,
however, longer may be needed before habitat that will support newts is
established. Adding log, rock or turf stacks to newt habitat will provide immediate
cover, and the selected planting density of trees or sowing rates of seed will
influence the time it takes suitable ground cover to develop and for invertebrates
and small mammals to increase their numbers. Rock or log heaps should be
located in areas where they will not get in the way of machinery needed to
manage other habitats. The deep mulching of tree-planted areas mimics a litter
layer and can be very beneficial. (See 'Provision of refuges/over-wintering sites'
page 31, for more detail).
Grassland swards
can be established by either sowing seed or by leaving the
ground to colonise naturally and imposing a mowing regime. Wherever possible,
good quality habitat should surround a new pond, so that newts have a choice of
direction when leaving the water.
Grassland around
great crested newt breeding ponds should be managed in a way
that is sensitive to the maintenance of both newts and the grassland sward. The
aims of management should be to provide floristically-rich, invertebrate-rich and
structurally varied habitat with a minimum of disturbance to newts in the process.
To maintain grassland
as grassland, the sward will require cutting or grazing at
least annually at a time when newts are less likely to be harmed. A 'traditional'
hay cut during hot dry weather in June or July is unlikely to interfere greatly with
newt activity. This involves cutting, drying and baling the hay over a period of about
a week. Grazing by sheep, horses or cattle may also benefit the grassland sward,
although overgrazing must be avoided. Where possible it is beneficial to leave a
margin of uncut vegetation up to five metres or so in width around some of the
pond margins and alongside hedges, streams or other boundaries to ensure the
presence of some dense cover throughout the year.
Scrub and woodland
management
To maximise the
potential of scrub and woodland for newts, such areas should be
divided into compartments for management purposes, and felled or coppiced on a
small scale rotational basis to ensure that disturbance at any one time is
minimised. Where coppicing is taking place, cut timber can be stacked to provide
useful refuge areas for newts. Haul routes should be minimised to reduce ground
disturbance.
Shelter
Studies show that
land habitats with a well developed litter layer and dead wood
component are favoured by newts. Rocks, logs and gaps in the ground, especially
in moist, shaded places or under dense ground cover provide ideal places for
newts to rest during the day or to remain during cold or very dry weather. Ditch
and hedge banks increase the surface area of land, provide a sheltered
microclimate, and often have mammal burrows that newts may share. Networks of
burrows made by voles, moles, rabbits and shrews, may be quite extensively
adopted by newts.
Providing wood and
rock piles for shelter and over-wintering is important in
management for great crested newts. Dead wood and the thick litter layer of old
woodland and scrub provides the moist stable environment that they need.
Mulching
Providing a deep
litter layer (100mm or preferably more) of deciduous or mainly
deciduous bark mulch artificially creates a litter layer. Composted bark mulch is
even better as it compacts well and holds moisture more effectively. Used in
association with new tree plantations it can be immediately successful in providing
habitat for newts. Mulch also reduces growth of ground flora that competes with
newly planted tree stock. As plantations grow and are thinned, the cut poles and
branches can be left on the surface between trees as further dead wood. By 10-15
years the plantation should provide good quality newt habitat, as an understorey of
bramble, ivy or other plant cover develops.
Logs
Fallen dead wood
under which newts can shelter and feed may be supplemented
with cut logs. These can be placed directly on the ground or in a shallow
excavation with spoil and turf in
between and on top
of the logs. Where possible, log piles should be positioned in
shady places where sunlight will not dry them out too much.
Stones and rocks
Stone, rock, clean
brick rubble (without cement residues) and old or misfired
bricks can be used in a similar way to logs to provide shelter and feeding areas.
Building successful rock and log piles can be time consuming and requires careful
attention to the timing of delivery and spreading of materials. As with log piles,
stone can be placed in shallow excavations made by taking spoil to spread
amongst and over the logs or stones. On clay or slow-draining soils, great care
must be taken to ensure drainage is adequate and the refuge is not in a flood
zone, as the lower part could become waterlogged in heavy rain.
The position for
rubble heaps can be anywhere within 200 metres of a pond, but in
general, the closer they are to the ponds, the better. Refuges that blend into the
environment are best. Avoid unattractive, messy heaps which have the appearance
of fly-tipping as these may generate complaints. Encouraging moss and grass to
grow on wood/stone piles by adding soil to the top and inside of heaps may
increase the humidity and stability of the environment.
Habitat link factors
Routes to other
ponds
Populations of newts
tend to be stabilised where there are opportunities for adults
to migrate from pond to pond in times of high productivity. Networks of grassland
between a collection of ponds is a good management strategy to offset chance
variations in breeding success at individual ponds, and the occasional disaster
which causes local extinction.
Public disturbance factors
A number of methods
may be deployed to minimise the likelihood of fish
introductions and to reduce excessive public disturbance. It is important that
positive messages are given out rather than a list of 'do not' rules. Leaflets and
display boards can help to reinforce local bylaws and management plans.
Information may be supplied to school teachers and others who may take and
release back to the wild small numbers of plants and animals as a part of their
work or pastime. The particular danger of releasing carnivorous fish such as
sticklebacks, perch and pike should be highlighted, as some wildlife guides and
gardening books do not warn of the effect that these very
In general, the
more visitors a pond has, the greater the chance of unauthorised
release of unwanted animals and plants and other damage. In urban areas it may
be difficult to limit the disturbance of ponds. To protect newts at such places may
mean keeping the main breeding site in a secluded or inaccessible area. Deeper
ponds, however, may prove irresistible to those who move freshwater fish without
permission. Although it is illegal, the release of fish for angling purposes without a
Consent from the Environment Agency has, like habitat destruction and neglect,
been one of the biggest threats to newts.
The degree of acceptable
disturbance will vary according to each site. Ultimately,
outside nature reserve areas, a successful strategy to keep one or more newt
breeding sites viable will depend upon managing the demands of the public so that
these important ponds are kept primarily for wildlife use. Creating new ponds in an
appropriate area may in some cases be the only way of achieving this.
Ways to improve
the seclusion of ponds include:
Diversion
of footpaths away from pond edges.
Planting
of hedges or narrow tree belts to screen ponds from being
noticed and approached. Note: do not plant too close to ponds with trees
that may grow and shade or take excessive water from the pond.
Fencing
or railings (in urban areas) to prevent complete access around
a pond edge. It may be possible to protect a proportion of pond edge from
disturbance.
Management projects
This section describes the jobs, their resourcing and timing that are required to
control the above
factors to meet the objective..
Monitoring projects
Counts
If monitoring (measuring population size changes over time) is being undertaken, it
should be noted
that newt population size can fluctuate between years, sometimes quite considerably. This is not
necessarily a cause for concern, but may be part of a normal process. Long-term monitoring,
ideally over many years, is needed to reveal any meaningful trends in newt populations (see later).
The surveyor should be aware of the limitations of counts. They can vary dramatically
for a single
population from one day to the next, and in particular, are affected by temperature fluctuations.
Also, the variable nature of ponds affects the ease with which newts can be counted. For example,
they may be less easily observed in turbid or weedy ponds. Repeating the counting process can go
some way towards compensating for variation in newt visibility in ponds where water clarity varies.
At least three, and preferably six, counts per year are recommended. These should be carried out
over the course of the main breeding season, under suitable weather conditions. The highest count
obtained should be used to score the population. If comparisons between population are being
made, or if changes in population size over time are being considered, then ideally the average of
the same number of counts for each year is used. When assessing populations in a closely-
spaced group of ponds (within 250 m of each other) counts can be added together to give a
cumulative site score.
Licensing
The great crested newt is strictly protected in Britain through the Wildlife and Countryside
Act 1981
(as amended) and the Conservation (Natural Habitats etc.) Regulations 1994. This legislation not
only protects great crested newt habitat, but also makes it an offence to capture or disturb the
species. A licence allows an otherwise unlawful activity to occur for a certain reason, such as
conservation. If it is anticipated that great crested newts will be encountered during a survey, then
generally it is advisable to obtain a licence first, and certainly if you are going to use methods
which involve capture or disturbance (licences are issued by the relevant Statutory Nature
Conservation Organisation).
Surveying for newts involves working close to water bodies, often after dark. Surveyors
should be
aware of two types of potential health and safety issues: hazards associated with water bodies
(e.g. drowning and disease) and possible dangers associated with working outside at night,
particularly in urban or suburban areas (e.g. theft or assault). Danger can be minimised by visiting
all sites during daylight, prior to night-time surveys, carrying a mobile phone and avoiding working
alone. Surveying for newts can usually be carried out without getting wet. However, where bankside
vegetation is dense this may necessitate wading through some areas, and egg searching may
involve immersing hands in pond water.
Three main diseases to be aware of are Tetanus, Weil's disease (leptospirosis) and
Hepatitis A.
Weil's disease and Hepatitis A can be contracted through ingesting infected water and Weil's
disease can also enter the body through mucous membranes and broken skin. To protect against
disease:
ensure
that Tetanus boosters are adequate
do
not expose open wounds to pond water
do
not ingest pond water
in
case of injury, or if illness follows working near water, seek immediate
medical
advice.
Torching
Searching a pond
by torchlight between shortly after dusk and midnight is an effective
means of detecting adult newts. The surveyor should walk slowly around the pond, checking
for newts in the torch beam, paying particular attention to marginal vegetation and potential
display areas on the pond bottom, and scanning every 2-3 metres or so as gaps in pond
bank vegetation allows. March to June is the best time, and warm, still evenings without rain
are most productive. Although newts are active in rainy and windy conditions, the water
surface can become too disrupted for clear viewing. Larvae can also be detected by torching
during late summer and autumn. The activity of newts, and hence their visibility during torch
surveys, is heavily influenced by temperature.
In days following
frozen or very cold conditions, newts can be so inactive in ponds that they
go undetected. The air temperature below which torching becomes less reliable has not
been established but 5°C can be taken as a working guide. A powerful torch is needed and
waterproof rechargeable ones are most suitable. For most ponds, a torch with 100,000
candle power is adequate but when viewing water from greater distance (e.g. from 5-10
metres away at the edge of a flooded quarry), spot lamps of up to 1,000,000 candlepower
can be used. Care must be taken with high power spot lamps as, at close range, these
may cause extensive disturbance and possibly damage to animals.
Torching is a suitable
technique for measuring relative abundance. Perhaps the most
important issue regarding the choice of torch for those counting newts rather than recording
presence/likely absence, is that of consistency. To compare counts between ponds or over
time, the same type of torch, bulb and battery strength should be used in each case.
Torchlight counts
are prone to showing apparent 'declines' in adult numbers over the
summer as vegetation cover increases and breeding activity ends, reducing the visibility of
newts. In very turbid or densely vegetated ponds, torch surveys are unsuitable.
To gain a population
score the surveyor should make a single circuit of the pond and count
the total number of adult newts seen by torchlight.
Bottle trapping
Bottle traps are
an effective way of detecting and assessing a population, but they do have
several drawbacks. Bottle trapping can be logistically onerous and there is a risk of harming
newts and small aquatic mammals. Due to the problematic nature of bottle trapping it is
recommended only in limited cases. It could be used for checking weedy or turbid ponds
where torching is not reliable for example, or for ponds at which night-time access (for
torching) is restricted.
Bottle trapping
normally requires two visits to a pond for each trapping session; an evening
visit to set the traps, followed by an early morning visit to check them. It can take a long
time to set, collect and transport a large number of traps to and from a pond (see reference
38). The use of bottle traps demands considerable care and should be carried out only by
thoroughly trained persons. If traps are fully submerged and prevent newts rising to the
surface of the water to breathe, then the newts may eventually suffocate. Warmer water
holds less oxygen, so this risk increases in hot weather and also in small, well-weeded and
heavily silted ponds. For information on bottle trapping.
Drift fence
and pitfall traps
Drift fences and
pitfall traps are commonly used in studies of amphibian ecology. As a
conservation survey tool they can be used to show the direction of arrival at, and departure
from a pond, or to detect occurrence and movements on land.
Pitfall trapping
is time consuming and labour intensive and can, like bottle trapping hold
risks to amphibians, mammals and other wildlife.
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