wickham hall farm bishop`s stortford great crested newt report

WICKHAM HALL FARM
BISHOP’S STORTFORD
GREAT CRESTED NEWT REPORT
Report for
Sworders Agricultural
October 2010
Client:
Sworders Agricultural
Title:
Wickham Hall Farm, Bishop’s Strortford
Great Crested Newt & Bat Survey
Project No:
AEL 300
Date of Issue:
Draft – 14 June 2010
Final - 22 October 2010
Status:
Final
Signed on behalf of Applied Ecology Ltd:
Dr Duncan Painter
Director
CONTACT DETAILS:
APPLIED ECOLOGY LTD
St. John's Innovation Centre
Cowley Road
Cambridge
CB4 0WS
Tel: 01223 422 116
Fax: 01223 420 844
Mobile: 07725 811 777
Email: [email protected]
Wickham Hall Farm
Great Crested Newt Report
Contents
1
1.1
Introduction ............................................................................................................................2
Background..............................................................................................................................2
2
2.1
2.2
2.3
Great Crested Newt ...............................................................................................................3
Background..............................................................................................................................3
Survey Approach ....................................................................................................................5
Survey Findings ......................................................................................................................7
3
Development Impacts & Mitigation ..................................................................................9
Applied Ecology Ltd
Wickham Hall Farm
1
INTRODUCTION
1.1
BACKGROUND
1.1.1
Great Crested Newt Report
Applied Ecology Ltd was commissioned by Sworders Agricultural to complete a
great crested newt Triturus cristatus presence / absence survey of ponds located
around a proposed re-development of farm buildings at Wickham Hall Farm,
Bishop’s Stortford, Hertfordshire, CM23 1JG. In addition to the newt survey a
visual inspection of the farm buildings was completed for evidence of their use by
roosting bats and is reported separately.
1.1.2
The great crested newt survey was completed during the peak of the 2010
amphibian breeding season between by an experienced AEL ecologist (Dr Duncan
Painter CEnv MIEEM) under the auspices of his Natural England GCN survey
and handling licence (no. 20100376).
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2
GREAT CRESTED NEWT
2.1
BACKGROUND
2.1.1
A survey for great crested newts (referred to hereafter as GCN) was first
completed by other consultants in July 20061. This investigated four standing
water bodies within 500m of Wickham Hall farm buildings, one of which was
completely dry and one nearly dry at the time of the survey. No GCN were found
in any of the water bodies and the report concluded that development at
Wickham Hall would have no impacts on any known GCN habitat. It is of note
that the 2006 survey was conducted at a time that was outside the recognised
survey window for conducting GCN survey, and relied solely on the use of a
pond net to catch GCN and did not therefore comply with best practice survey
guidance for this species.
Great Crested Newt Ecology
2.1.2
Great crested newt (GCN) is one the UK’s most threatened amphibian species and
has demonstrated a marked decline in abundance during the second part of the
twentieth century.
Like all UK amphibians, GCN relies on water bodies for
breeding but otherwise spend much of their lives on land.
2.1.3
Adult newts commence their migration to breeding ponds after emergence from
winter hibernation, which depending upon local weather conditions, can take
place from late January to mid March. Movements tend to occur following rain
when air temperatures are greater than 5oC. Peak courtship and egg-laying is
normally from mid-March to mid-May. During this time females lay two or three
eggs a day over a period of several weeks, and can lay up to 200-300 eggs in total.
The eggs are placed on submerged aquatic plants, and carefully wrapped in
leaves.
2.1.4
The larvae hatch after about three weeks and feed on a range of small aquatic
invertebrate prey. They complete their metamorphosis into air-breathing juveniles
about four months later. Juvenile emergence from the breeding pond normally
takes place in August and lasts for around two months. Juvenile newts then take
between two and four years to reach sexual maturity during which time they are
mainly land based. Adult newts generally leave the breeding ponds from late
Jones & Sons Environmental Sciences Ltd (August 2006) Wickham Hall Ponds Bishops’s Stortford
Hertfordshire 2006 Great Crested Newt Report. Report for Sworders Agricultural
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Great Crested Newt Report
May onwards.
2.1.5
Adults and immature newts spend the winter in places that provide shelter from
frost and flooding typically between October and February. Hibernation sites will
vary but can include underground refuges amongst tree roots, in mammal
burrows, or above ground sites under deadwood or rubble piles for example.
2.1.6
Breeding ponds are usually small to medium-sized (around 50-250m²) with
plentiful aquatic vegetation for egg-laying. Optimum ponds for breeding newts
typically
possess
abundant
submerged
plant
material
with
prolific
emergent/floating vegetation covering approximately one third of the water
surface. Such well-established, mid-succession ponds will also ideally contain less
vegetated areas to allow adult males to display in clear view of females. GCN can
be found in both acid and alkaline water bodies although they are more
frequently found in water that is close to neutral or slightly alkaline. Ponds that
dry out infrequently can support very good populations as periodic drying
reduces the populations of the newts’ main predators, principally fish and
dragonfly larvae. Ponds also need to support a healthy invertebrate fauna to
provide food for developing newt larvae. Clusters of suitable ponds have been
found to greatly enhance great crested newt breeding success.
2.1.7
There are four primary requirements for great crested newt terrestrial habitats, (1)
permanent areas of refuge habitat for shelter in extreme weather conditions, (2)
foraging opportunities, (3) daytime refuges, and (4) dispersal opportunities.
Habitats that meet many of these requirements include broad-leaved woodland,
rough grassland and scrub, and a mixture of these in close proximity is ideal.
2.1.8
In order to help maintain populations it is important that newts are able to
successfully move between hibernation sites and breeding ponds, as well as other
sites. To allow this to happen there should be areas of suitable land habitat
between areas. Studies have shown that newts commonly move between ponds
that are within around 250 metres of each other. Barriers that inhibit migration
and dispersal include roads with large volumes of traffic, large or fast-flowing
rivers, built-up areas, and large expanses of intensively farmed land.
Great Crested Newt Legislation
2.1.9
GCN is fully protected under the Wildlife and Countryside Act, 1981, (as
amended and as strengthened by the CROW Act, 2000) and the Conservation
(Natural Habitats, &c.) Regulations 1994 that implements the EC Directive
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92/43/EEC in the UK. It is an offence, with certain exceptions, to:
•
Intentionally or deliberately capture, kill, or injure GCN;
•
Intentionally or recklessly damage, destroy, and disturb GCN in a place used
for shelter or protection, or obstruct access to such areas;
2.1.10
•
Damage or destroy a GCN breeding site or resting place;
•
Possess a GCN, or any part of it, unless acquired lawfully; and
•
Sell, barter, exchange, transport, or offer for sale GCN or parts of them.
The legislation covers all newt life stages such that eggs, tadpoles and adult newts
are all equally protected. Actions that are prohibited can be made lawful by a
licence issued by the appropriate statutory authority.
2.1.11
GCN can commute up to 500m from their breeding ponds, with most being found
within 250m of a breeding site in suitable habitat.
2.2
SURVEY APPROACH
2.2.1
Guidance for GCN survey has been produced by English Nature2.
2.2.2
In order to prove GCN presence or absence from a pond in relation to
development, EN 2001 recommends three survey methods should be completed
in all ponds within theoretical GCN commuting range of the development site.
These are torch survey, bottle [or funnel] trapping and egg searching. The same
best practice guidance also recommends that four separate survey visits should be
completed between mid-March and mid-June as a reasonable standard of survey
effort to prove GCN presence/absence, with at least two of the visits being
completed during the theoretical peak in GCN numbers in their breeding ponds
between mid-April and mid-May.
2.2.3
The methodological approach adopted by this survey was based on the use of
three methods, torch survey, funnel-trapping and egg searching between 22 April
and 10 May 2010.
2.2.4
A walkover survey of the site was first conducted to locate all previously
identified water bodies and any additional standing water habitat that may have
not been evident previously.
2
English Nature (2001) Great crested newt mitigation guidelines. Version August 2001
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2.2.5
Great Crested Newt Report
A total of six standing water bodies are present within 500m of the site as
indicated by Figure 1. A visual assessment of each was conducted to assess their
suitability as habitat for GCN using the Habitat Suitability Index (HSI) approach
Natural England advises should be completed as part of GCN assessment of
ponds.
2.2.6
2.2.7
The HSI scores for each pond were as follows:
•
Pond 1 – 0.47
•
Pond 2 – 0.49
•
Pond 3 – 0.56
•
Pond 4 – 0.49
•
Pond 5 – 0.23
Only one water body (Pond 3) had an HSI score above the 0.5 threshold that
makes it theoretically suitable aquatic habitat for GCN breeding. Water bodies
with scores of less than 0.5 are generally regarded as being unsuitable for GCN.
2.2.8
Pond 5 was a private fishing lake reported to be stocked with rainbow trout. An
extensive search of submerged aquatic vegetation that was suitable for GCN egg
laying was conducted on 22 April around its entire margin, and despite the
presence of numerous suitable submerged aquatic plants being present, no newt
eggs were found. On this basis and the obvious presence of a large predatory fish
population, and the very low HSI score, no further survey work for GCN was
conducted as the water body was clearly unsuitable habitat for GCN.
2.2.9
All the remaining water bodies (Ponds 1-4) were surveyed for GCN presence /
absence as outlined below.
Funnel Trapping
2.2.10
Double ended funnel traps (40cm x 20cm, with a 3mm square mesh) were set at
regular intervals around the accessible perimeters of Ponds 1-4 in order to capture
newts. The traps work on the same basis as plastic drinks bottle traps but are
larger and have two as opposed to one inverted funnel entrance. They are set such
that the top third of the trap is out of the water in order that any captured newts
can reach the water surface to gulp air and therefore not die from asphyxiation – a
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Pond 5
Pond 4
Pond 3
Pond 2
Pond 1
N
Wickham Hall Great Crested Newt Survey
Figure 1: Pond locations
Pond 1
Pond 1
Pond 2
Pond 3
Pond 4
Pond 5
Wickham Hall Great Crested Newt Survey
Photo-sheet 1 of 1
Photos taken April 2010
Wickham Hall Farm
Great Crested Newt Report
potential problem with plastic drink bottle traps. The number of traps used was
proportional to the range of littoral aquatic habitats present in each water body
and were set at approximately 2m centres around the accessible perimeters of all
water bodies.
2.2.11
The traps were set in the evening of 21, 22, 27 of April and 9 May and retrieved
the following morning in accordance with the recommended trapping times
described by EN 2001.
2.2.12
A total of 15 funnel traps were set around the perimeter of Pond 1, seven around
Pond 2, five around Pond 3 and five around Pond 4 on each survey occasion.
Egg Searching
2.2.13
A search for GCN eggs on a selection of suitable submerged aquatic vegetation
was conducted on each survey occasion until such time that GCN eggs were
found. Searches were conducted for approximately 15 minutes on each occasion.
Torch Light Survey
2.2.14
A one million candle power torch (Clulite CB2 Clubman Deluxe) was used to
conduct an after dark torch light survey of each water body on the first survey
occasion in April 2010. The survey was undertaken in complete darkness between
the hours of 21.00 and 22.00 by walking slowly around the perimeter of each
water body and shining the torch into the water to enable a count of all newts
seen to be made.
2.2.15
The effectiveness of torch survey in three of the four water bodies was severely
limited by two different factors. These were turbid water in Pond 1, and the
presence of floating algae in Ponds 2 and 4, which restricted views through the
water column to such an extent that funnel trapping the same evening caught
significantly greater numbers of newts than seen with the torch. On the basis of
the obvious limitations of the torch survey the method was not repeated.
2.3
2.3.1
SURVEY FINDINGS
GCN was captured in the funnel traps in three of the four ponds that were
surveyed as follows:
•
Pond 1 – no amphibians seen or captured on any occasion – a coarse fish
stocked lake unsuitable for GCN.
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2.3.2
Great Crested Newt Report
•
Pond 2 – total no. of GCN caught on each survey occasion: 15, 8, 9, 2
•
Pond 3 – total no. of GCN caught on each occasion: 1, 2, 0, 0
•
Pond 4 – total no. of GCN captured on each occasion: 0, 1, 0, 0
On the basis of the survey findings reported above, it would appear that Pond 2 is
likely to support a “medium” sized GCN population, and Ponds 3 and 4 a small
GCN population according to EN 2001.
2.3.3
No GCN eggs were found in any of the ponds, however egg bound female GCN
were caught from Pond 2 that were considered most likely to be laying eggs on
submerged leafs as no other suitable aquatic vegetation was present due to the
high degree of shade the pond was subject to from surrounding woodland.
2.3.4
Pond 3 supported at least three different GCN (including male and female
animals), and it is considered likely that it was present as a small breeding
population. A single GCN egg was found on submerged aquatic vegetation on
the second survey visit occasion.
2.3.5
A single sub-adult male GCN was caught in Pond 4 on one survey occasion only.
The pond does not appear to support a breeding population of GCN and is mostly
likely being used as a feeding site by newts.
2.3.6
In addition to GCN, smooth newts were caught using funnel traps from Pond 2
(maximum 5 animals), Pond 3 (maximum three animals), Pond 4 (maximum 10
animals).
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3.1.1
Great Crested Newt Report
DEVELOPMENT IMPACTS & MITIGATION
The survey has verified the presence of two breeding populations of GCN within
commuting range of the development site.
3.1.2
Future development involving the loss of any terrestrial habitat of potential value
to GCN, notably woodland, rank grassland, hedgerows and scrub that is located
within range of the breeding ponds may result in the accidental killing and injury
of GCN and would need to be implemented under the auspices of a Natural
England development licence that can only be issued once planning permission
for the development has been issued.
3.1.3
For the purposes of informing the planning application, it will be necessary to
provide outline details of the mitigation strategy that will be adopted to minimise
adverse short and long term impacts on GCN in order to demonstrate that they
are feasible to implement.
3.1.4
On the basis of the outline development plans discussed with Sworders, the GCN
mitigation approach would be as follows:
•
Retention, protection and enhancement of the existing GCN breeding and
terrestrial habitat resource;
•
Creation of compensatory newt friendly habitat areas (e.g. new woodland
and hedgerows) to replace and enhance terrestrial habitats of value to GCN
that are to be lost or damaged as a result of the development.
•
Use of temporary amphibian fencing (TAF) and pitfall traps to isolate and
capture GCN from all terrestrial habitats within GCN range of breeding
ponds that are to be lost/damaged as a result of development construction
during the newt active period (April to October).
The amount of effort
(capture nights) that will be required to clear areas of GCN will be dependent
upon the size of the GCN population impacted – this would normally require
a six-visit breeding pond survey during the Spring. For medium sized GCN
populations, the minimum number of trapping nights to clear terrestrial areas
of newts would be 60 nights in suitable conditions (damp ground and
minimum night time temperatures of above five degrees Celsius).
•
Integration of new hard landscapes to minimise adverse impacts on GCN as a
result of the operational development e.g. the use of a newt-friendly surface
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Great Crested Newt Report
water drainage scheme e.g. avoiding the use of ill sited gulley pots that GCN
could fall into.
3.1.5
In practice the development has been designed to minimise adverse impacts on
GCN as far as is practicable, and an associated landscape masterplan has been
produced (see Appendix 1) that shows it will be possible to mitigate any adverse
development impacts on GCN and enhance the population integrity of GCN
within the site in the long-term.
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Appendix 1
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