DESIGN MANUAL FOR ROADS AND BRIDGES
VOLUME 10 ENVIRONMENTAL
DESIGN AND
MANAGEMENT
SECTION 4 THE GOOD ROADS
GUIDE - NATURE
CONSERVATION
PART 7
HA 116/05
NATURE CONSERVATION ADVICE IN
RELATION TO REPTILES AND ROADS
SUMMARY
This Advice Note identifies the impact new and existing
roads are likely to have on native reptile populations
and how those impacts can be mitigated.
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DESIGN MANUAL FOR ROADS AND BRIDGES
HA 116/05
THE HIGHWAYS AGENCY
SCOTTISH EXECUTIVE
WELSH ASSEMBLY GOVERNMENT
LLYWODRAETH CYNULLIAD CYMRU
THE DEPARTMENT FOR REGIONAL DEVELOPMENT
NORTHERN IRELAND
Nature Conservation Advice in
Relation to Reptiles and Roads
Summary:
This Advice Note identifies the impact new and existing roads are likely to have
on native reptile populations and how those impacts can be mitigated.
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Part 7 HA 116/05
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May 2005
DESIGN MANUAL FOR ROADS AND BRIDGES
VOLUME 10 ENVIRONMENTAL
DESIGN AND
MANAGEMENT
SECTION 4 THE GOOD ROADS
GUIDE - NATURE
CONSERVATION
PART 7
HA 116/05
NATURE CONSERVATION ADVICE IN
RELATION TO REPTILES AND ROADS
Contents
Chapter
1.
Introduction
2.
Key Issues
3.
Protection Status
4.
Background Biology
5.
Reptile Habitat
6.
Reptile Survey Methods
7.
When are Reptile Surveys Necessary?
8.
Licensing Considerations and Qualifications
9.
Possible Effects on Reptiles
10.
Mitigation Measures
11.
Contract Implementation
12.
Monitoring
13.
Enquiries
Annexes
Annex A
Annex B
Annex C
Annex D
Annex E
Annex F
Annex G
Annex H
Annex I
Annex J
May 2005
Review of Legislation and Guidance
Design of Reptile-Proof Fencing
Artificial Refuge Specification
Hibernacula Design
Desk Study Consultees
Photographic Examples of Principal Issues
Decision Matrix
Acknowledgements
Further Reading
Glossary
VOLUME 10 SECTION 4
PART 7 HA 116/05
CHAPTER 1 INTRODUCTION
1.1
STATUS AND PROTECTION
All reptile species receive some level of protection under UK law. Two of the six reptile species
native to the UK, sand lizard (Lacerata agilis) and smooth snake (Coronella austriaca), receive
full protection. In practice, this level of protection also serves to provide some level of
protection for their habitats. The sand lizard is endangered in northern Europe in particular and
has a very restricted distribution in England. Smooth snakes have a very restricted distribution
in Britain, although the species is widely distributed across much of central and southern
Europe and occupies a greater range of habitat types on the continent. Both species are
particularly vulnerable to anthropogenic effects.
The other species native to the UK are: adder (Vipera berus); grass snake (Natrix natrix);
common lizard (Lacerta vivipara); and slow-worm (Anguis fragilis). Although more common,
these other species are believed to be suffering local declines.
The sand lizard is a Priority Species in the UK Biodiversity Action Plan (UKBAP) and a Species
Action Plan (SAP) for its conservation has been produced. A number of Local Biodiversity
Action Plans also include SAPs for reptiles, and the Herpetological Conservation Trust has
produced a SAP for the smooth snake.
important habitat features can also be important to successive generations, and involve them
undertaking regular seasonal movements, sometimes using well-established route-ways.
In certain circumstances, road traffic may directly cause reptile mortality. Reptiles occur on
road verges throughout the UK, and therefore routine maintenance works on the soft estate
can also have significant effects upon them.
1.3
SCOPE OF THE ADVICE
This Advice Note provides details of the effects of roads on reptiles, and the methods available
to mitigate these effects. No particular solution will be appropriate in every instance and advice
should be sought from experienced specialists and the appropriate Statutory Nature
Conservation Organisation (SNCO) and overseeing organisation on a case-by-case basis.
Given the widespread nature of reptiles within the soft estate and their relevance to the
existing road network, from Chapter 6 onwards both new schemes and the existing road
network are considered in parallel. Technical terms are explained in the Glossary (presented
as Annex J).
The advice in this document is likely to be helpful to the development and delivery of the
Highways Agency, Transport Wales and The Scottish Executive Transport Group in the
development of their respective BAP objectives.
With the exception of sand lizard and smooth snake, which are restricted to very specific
habitat types, reptiles are widespread, often occurring in rural and urban situations, and thus
can be affected by the construction and operation of highways in virtually any location.
1.2
POTENTIAL IMPACTS
New road schemes, road improvements and maintenance operations can affect reptiles by
destroying, degrading or fragmenting habitats. Reptiles require a variety of habitat types at
different times of year, as well as at different times of day, for basking, foraging and
hibernation. It is also important to remember that the suitability of reptile habitat is not simply a
function of vegetation type, but vegetation structure, substrate type, aspect and microtopography. Each of these factors therefore need to be considered when assessing the likely
impacts of roads on reptiles.
Small areas of habitat and specific features can be important to relatively large reptile
populations, a particular example being communal hibernation sites. The loss of particular,
often subtle, habitat features can therefore have disproportionately large effects. In some
cases, especially for the more behaviourally complex and wide-ranging species, these most
MAY 2005
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CHAPTER 2 KEY ISSUES
2.1
THE SPECIES
2.4
FACTORS AFFECTING REPTILES
Of the six native reptile species resident in the UK, two (sand lizard and smooth snake) are
considered rare or endangered in this country. Sand lizards are restricted to lowland dry
heaths and coastal sand dunes; and smooth snakes are generally confined to lowland heaths.
Adders, slow-worms, common lizards and grass snakes occupy a range of habitat types.
Since they occur in both urban and rural situations, and since relatively small sites can be of
disproportionate importance, reptiles can potentially be affected by virtually any highways
operations.
The potential effects of new road construction or road improvements include the loss,
degradation and fragmentation of habitats used by foraging, basking and/or hibernating
reptiles. Conversely, existing road verges can represent important linear features that help to
link habitats and populations in otherwise disparate landscapes. New road schemes also have
the potential to link fragmented populations and extend the range of others through the
creation of inter-connected habitat features on the soft estate. These issues are discussed in
more detail in Chapter 9.
2.2
During the operational phase, effects can include reptiles being killed on roads, damage to
adjoining habitats (for example fires caused as a result of road-related activities), and the
continuing effects of fragmentation. Maintenance operations can potentially affect reptiles
using habitats and features within the soft estate.
LEGAL PROTECTION
Sand lizards and smooth snakes are strictly protected under UK and European legislation.
Licences are issued by the relevant SNCOs for activities which require the handling or
disturbance of these species as part of surveys or related activities. The Appropriate Authority
(as identified in the Conservation (Natural Habitats &c.) Regulations 1994) can issue licences
to permit otherwise prohibited acts associated with development projects; this is described in
more detail in Annex A.
Reasonable measures need to be taken to avoid the incidental killing or injuring of common
lizards, slow-worms, adders and grass snakes in the context of development activities.
Although licences are not required for development activities affecting these species, in order
to ensure compliance with the relevant legislation, it is necessary that the best practice
guidance set out in the following parts of this document be implemented in consultation with
the relevant SNCO.
2.3
BEST PRACTICE
All highways operations should take account of the potential presence of reptiles by
appropriate survey work, and the development of effective and proportional mitigation. A key
element is the appropriate timetabling of works, to take account of the seasonal patterns of
reptile behaviour, the seasonal importance of different areas and features, and the seasonal
constraints on mitigation.
2.5
MITIGATION
It is possible to mitigate the effects of highways operations on reptiles by seeking to avoid the
most sensitive and/or important habitats and features. Habitat creation, habitat management
and the provision of artificial hibernation and refuge sites may be used as a means of
improving habitats for reptiles. Little is known about the use of artificial structures such as
mammal or amphibian tunnels by reptiles, but the provision of safe routes to cross roads may
also play a role in helping to reduce the effects of fragmentation.
Where necessary, capture and relocation operations can be undertaken in order to prevent
the killing or injuring of reptiles during construction or maintenance works. Planning is critical
to carrying out effective mitigation. Relocations, for example, should always be carried out
over at least one spring and early-summer period, and should include a commitment to habitat
creation or management to promote the survival of relocated animals. Reptiles exhibit
significant seasonal variations in behaviour (and in some cases habitat requirements), thus it
is often possible for works to be timed to avoid periods when reptiles are most at risk.
Mitigation measures for new schemes and the existing road network are dealt with in detail in
Chapter 10.
English Nature are currently developing guidelines for best practice in relation to reptile survey
and mitigation and the advice contained in this Advice Note has been developed largely in
parallel with the English Nature publication, but with special reference to highways issues.
MAY 2005
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CHAPTER 2 KEY ISSUES
2.6
VOLUME 10 SECTION 4
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EMERGENCY WORKS
Works which are undertaken in response to other legislative requirements, for example
emergency works undertaken on safety grounds, may also result in the death, injury or
disturbance of reptiles (possibly including smooth snakes and sand lizards). Where such
works may result in an offence, expert advice should be sought and the relevant SNCOs
should be informed where possible prior to the commencement of those works. In
circumstances where it is not possible to inform the relevant SNCOs prior to the
commencement of the works the relevant SNCOs should be informed as soon as practicable
after the commencement of the works and their advice sought. Such works should only
proceed where it is considered that they can not reasonably be avoided and where measures
have been put in place in accordance with section 10.3 to minimise any impact of the works
and in particular to minimise the damage or disturbance to the reptile or the damage or
obstruction to the structure or place where the works are being carried out. The legal
implications of works which could kill, injure or disturb reptiles and the various defences
relevant to highways operations are set out in Annex A and must be read in conjunction with
this paragraph
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CHAPTER 3 PROTECTION STATE
3.1
REPTILES AND THE LAW
All six native reptile species are protected under UK law. Smooth snakes and sand lizards
receive additional protection, including under European legislation.
A summary table (Table 3.1) is included below, and a brief description of their legislative
protection is given in Annex A. It must be stressed that these descriptions are summaries only:
the original legislation should always be referred to for the exact wording. If necessary, legal
advice should be sought.
3.2
STATUTORY NATURE CONSERVATION ORGANISATIONS IN
THE UK
are: in England, English Nature; in Scotland, Scottish Natural Heritage; in Wales, Countryside
Council for Wales; and in Northern Ireland, Department of the Environment for Northern
Ireland (Countryside & Wildlife). The contact details of each of the SNCOs are given in
Annex E.
3.3
APPROPRIATE AUTHORITIES IN THE UK
The relevant Appropriate Authorities with regard to licensing development(road)-related
activities which could affect sand lizards and smooth snakes are: the Welsh Assembly
Government in Wales (sand lizard); and Defra in England (sand lizard and smooth snake).
The contact details for these Appropriate Authorities are given in Annex E.
The SNCOs are responsible for licensing activities which require the handling or disturbance
of sand lizards and smooth snakes for conservation, education or scientific reasons. They
should be consultees for development-related activities which affect any reptile species. They
Table 3.1 Reptiles and the Law
Common name
Scientific name
Wildlife and Countryside Act (1981) and amendments
Conservation (Natural Habitats, &c.) Regulations (1994)
Common lizard
Lacerta vivipara
Part of Section 9(1); Statutory Instrument No.288 (1988)
-
Sand lizard
Lacerta agilis
Section 9
Part III (Schedule 2)
Slow-worm
Anguis fragilis
Part of Section 9(1); Statutory Instrument No.288 (1988)
Adder
Vipera berus
Part of Section 9(1); Statutory Instrument No.367 (1991)
-
Grass snake
Natrix natrix
Part of Section 9(1); Statutory Instrument No.288 (1988)
-
Smooth snake
Coronella austriaca
Section 9
Part III (Schedule 2)
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VOLUME 10 SECTION 4
PART 7 HA 116/05
CHAPTER 4 BACKGROUND BIOLOGY
4.1
INTRODUCTION TO THE SPECIES AND STATUS IN THE UK
There are three species of lizard native to Great Britain: common lizard (also known as
viviparous lizard), sand lizard and slow-worm (a legless lizard). The snakes comprise the
adder, grass snake and smooth snake.
The six species vary in their level of legal protection, reflecting their relative conservation
status in Britain and in Europe. The status of each of the species in the UK is summarised
below. All are either locally scarce and/or thought to be declining; even those which are
relatively common or widespread are considered to be of conservation concern.
Table 4.1 Conservation Status of UK Reptiles
4.2
UK DISTRIBUTION OF REPTILE SPECIES
4.2.1
THE MORE WIDESPREAD SPECIES
The slow-worm and common lizard are the most widespread and occupy habitats across all of
mainland Britain. Slow-worms are the only native species present on the Outer Hebrides, and
common lizards are the only species native to Northern Ireland and the Isle of Man. With
adders, both species are present on several of the Scottish islands, Anglesey and the Isle of
Wight. The adder has a patchy distribution across England, Scotland and Wales. Grass
snakes are the next most widespread species, with a range covering the whole of England
and Wales. Introduced populations of grass snakes occur in pockets in central and northern
Scotland.
Species
Status
4.2.2
Common Lizard
Widespread but locally declining, notably in southern and eastern
England. Common in Wales and parts of Scotland.
Sand Lizard
Endangered. Native populations restricted to Surrey, Dorset and
Merseyside coast.
Sand lizards and smooth snakes are largely restricted to central southern England. An
isolated population of sand lizards also occurs on the coast of northwest England. Sand
lizards have been introduced/re-introduced at a number of specific locations in recent years as
part of a national conservation strategy. These include sites in England, Wales and on Coll in
Scotland.
Slow-worm
Locally common in England and Wales (particularly in southern and
eastern England). Declining slightly in England, notably the East
Midlands. Localised in parts of central Wales. Severe declines
reported in parts of Scotland.
Adder
Grass snake
Smooth snake
4.3
DESCRIPTION
4.3.1
LIZARDS
Locally common, particularly in southern England and parts of
Wales, but less common and even rare over much of central and
northern England; and central and parts of West Wales. Population
has declined over much of England. Absent from parts of Scotland.
Absent from Northern Ireland.
The identification of the British reptiles is relatively straightforward. The legged lizards are the
hardest to differentiate, but sand lizards are larger and ‘thicker-set’ than common lizards, and
their colouration is more striking.
Locally common in Wales and England, except in the north.
Declines noted in south-west and north-west England and the West
Midlands. Parts of central Wales, Pembrokeshire and the Lleyn may
have more localised populations. Absent from Scotland except
through introduction. Absent from Northern Ireland.
Adult common lizards are approximately 150 mm in length and are most often brown in colour
with some variation in patterning, although colouring is extremely variable. Juveniles are
approximately 40 mm at birth and almost black in colour.
Considered endangered and in decline. In recent decades the
smooth snake has been recorded only in the counties of Dorset,
Surrey and Hampshire, where it is largely restricted to mature
lowland heathland.
Data compiled from several sources
MAY 2005
THE ENDANGERED SPECIES
Common lizards
Sand lizards
Sand lizards grow to 220 mm, and their colouration varies from yellow-green to brown. They
usually have dark bands, or series of dark markings along their backs along with two paler
dorsal stripes and dark mottling along their sides. These dark markings characteristically take
the form of ‘oscellate’ spots (dark markings with white or cream centres). The flanks of adult
males in the breeding season develop a striking green colouration. Juveniles generally have a
weaker version of the adult female markings, and hatchlings display the same ‘oscellated’
spots as the adults.
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CHAPTER 4 BACKGROUND BIOLOGY
Slow-worms
Slow-worms are legless lizards. They are distinguished from the snakes by their particularly
smooth scales and shiny appearance and, on closer inspection, by their less welldifferentiated head, distinctly cylindrical body, smaller eyes with closable eyelids and a broad,
flat, forked tongue. Adult slow-worms reach approximately 400 mm in length. Colouration is
generally pale-grey, through copper to chocolate brown. Juvenile slow-worms have gold/palegold coloured backs, with a metallic lustre, and a dark/black underside and vertebral stripe.
Adult males tend to be a uniform grey-brown, whereas females are brown, often with a metallic
sheen, a dark vertebral stripe and darker flanks. It is difficult to determine the sex of subadult
animals reliably.
4.3.2
Slow worm
Adder
Common lizard
Grass snake
Sand lizard
Smooth snake
SNAKES
Adders
It is important to recognise the adder as it is Britain’s only venomous snake. Its most
prominent feature is a dark zig-zag stripe along the back. Bodies vary in colour between
whitish to red-/chocolate-brown, and the stripe from dark brown to black. Entirely black
individuals with only faint characteristic markings are not rare, so inexperienced surveyors
should be wary when faced with a snake which they cannot identify easily. The eye is small
but noticeably red, with a vertical pupil. The tail is generally easy to distinguish, and the overall
appearance of the adult is of a short, fat snake. Adult adders reach approximately
500-600 mm. It is generally possible to distinguish the sex of individuals on the basis of their
colour: females tend to have a chocolate-brown stripe on a brown background; males a black
stripe on a pale background. However, colouration is variable and a more accurate distinction
can be made on the number of ventral scales along the tail (males have longer tails) although
there is still some variation. Juvenile snakes all show female colouration.
Figure 4.2 UK distribution of reptile species
The maps summarise the approximate distribution of each of the reptile species in
Britain. Note that the small introduced/re-introduced populations of some species are
not shown. Desk study consultations, with the Herpetological Conservation Trust in
particular, should be effective in identifying the locations of the small introduced/
re-introduced populations of smooth snakes and sand lizards.
MAY 2005
Generally present in suitable habitat
Less common
Absent, except through re-introduction
Data not included
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CHAPTER 4 BACKGROUND BIOLOGY
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Grass Snakes
The grass snake can grow to over a metre in length (more often 700-800 mm) and is more
slender than the adder. Typically, grass snakes are grey-green or olive-green with black
markings along the flanks and a very distinctive collar of two black semi-circles bordering a
yellow (or orange or cream) band around the neck. The eye is conspicuous; yellow with a
round pupil. Although females tend to be larger, the sexes are generally very similar in
appearance. Females have a wider body and clearer distinction between their narrower tail.
The ‘penial bulge’ (the swelling around the vent associated with the hemipenes) in adult males
is reasonably obvious. Once again, the sexes can often also be differentiated on the bases of
the number of ventral scales along the tail.
Smooth snakes
Smooth snakes are smaller than both other snakes, being both more slender than an adder
and shorter than a grass snake. On closer inspection their scales lack the keel found on the
other snakes’ scales and hence are ‘smooth’. They are pale brown/grey in colour with two
rows of black spots along their backs, a heart-shaped black crown and distinctive black eyestripe. Adults reach approximately 600 mm. The sexes are similar in size, colour and
markings. As with grass snakes, gravid females in particular, tend to have broader bodies and
the males have a discernable penial bulge. Separation of the sexes is also possible (as
identified above for adders and grass snakes) by sub-caudal scale count but, as with the other
species, some overlap has been recorded. Males tend to have longer tails (more than 20% of
snout-vent length). Compared to our other snake species, the combination of markings and,
particularly, their behaviour tends to make smooth snakes very difficult to observe.
Figure 4.3 Photographs of the native reptile species
The photographs opposite illustrate each of the native reptile species. Photographs
are not to scale.
Adder
Smooth snake
Grass snake
MAY 2005
(a)
(c)
(e)
(b)
(d)
(f)
Slow-worm
Common lizard
Sand lizard
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CHAPTER 4 BACKGROUND BIOLOGY
4.4
FEEDING
Reptiles vary in their food preferences and dietary habits. Some species are fairly specialist
predators, whilst some are generalist predators or omnivores. Each species’ food preferences/
main prey are listed below:
l Common lizards and sand lizards feed predominantly upon invertebrates, hunting mainly
within vegetation and relying upon their excellent vision and speed.
l Slow-worms tend to prey largely upon small slugs and other soft-bodied invertebrates.
l The adder, the only venomous British reptile species, preys upon small mammals and
lizards. They kill by means of a poisonous (but not immediately fatal) bite. They often
then follow their prey using the dying animal’s scent trail.
l Grass snakes’ main prey species are amphibians, predominantly frogs and toads
(including tadpoles), though they will often predate fish and other small animals such as
small mammals and nestling birds.
l In the UK, Smooth snakes feed mainly upon lizards (largely the legged lizards, but also
slow-worms) and small mammals (often nestlings caught underground). Other prey
includes small snakes and invertebrates. On capture, they immobilise their prey within
coils of their body but are not true constrictors, tending to swallow their prey alive and
whole.
4.5.2
REPRODUCTION
Lizards
Common lizards give birth to 4-10 live young (hatchlings) with a peak at the end of July/early
August. Sand lizards lay eggs in open, exposed sand during June, with hatchlings starting to
appear during early August. Slow-worms give birth to 6-12 live young, usually during late
August/early September.
Snakes
Adders give birth to 6-20 live young in August, and smooth snakes to 4-15 young, usually
during late-August/September. Grass snakes lay eggs in June and July and need to incubate
their eggs, commonly using compost heaps, or piles of manure or grass cuttings. Hatchlings
appear during September.
4.5.3
HIBERNATION
There are some variations in the requirements for hibernation sites between the different
snake and lizard species, although a wide range of features tend to be used:
l
Crevices in soil and rock;
4.5
LIFE CYCLE
l
Fissures associated with roots and other buried material;
4.5.1
GENERAL
l
Small mammal and rabbit burrows;
l
Loose, sandy substrates;
l
Voids beneath artificial structures; and
In all British species, mating tends to occur between April and June. Two species (sand lizard
and grass snake) lay eggs, whilst the others give birth to live young.
l
Piles of rubble, dead wood or vegetation.
All six species of reptile hibernate during the winter months (October to March inclusive),
although the exact timing varies for different species. Each of the species needs access to
features which provide reliably frost-free conditions in which to hibernate.
These features are also typically associated with free-draining or at least partly free-draining
conditions, often in a bank of some kind or in sloping ground, and always avoiding positions
liable to be flooded.
Table 4.4 shows the periods of the year in which British reptiles are active. It is important,
however, to note that there will be significant variation with altitude and latitude, and smallscale variations following more extreme weather patterns.
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The manner in which the different species behave prior to and during hibernation varies, and
this can influence survey methodologies (see Chapter 6, ‘Reptile Survey Methods’). Adders,
for example, often migrate to their hibernacula and may be found in large numbers basking
near their communal hibernacula, both before and after the hibernation period and
occasionally during the winter when the outside temperature rises sufficiently. Common lizards
may also occasionally be observed during the winter. In addition, reptiles may move within
hibernacula, seeking optimum conditions of temperature and humidity in response to changing
conditions during the winter.
One implication of reptile hibernation patterns is that there may be physiological changes
approaching hibernation which could affect the success of translocations/relocations carried
out towards the end of the season.
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CHAPTER 4 BACKGROUND BIOLOGY
Table 4.4 Seasonal activity patterns of UK native terrestrial reptiles
Species
Activity
Common lizard
Hibernation
Adult activity
Jan.
Feb.
Mar.
Apr.
May
Jun.
Jul.
Aug.
Sep.
Occasional activity
Oct.
Nov.
Dec.
Occasional activity
Mating
Birth of young
Sand lizard
Hibernation
Adult activity
Mating
Egg-laying
Egg hatching
Slow-worm
Hibernation
Adult activity
Mating
Birth of young
Adder
Hibernation
Adult activity
Occasional activity
Occasional activity
Mating
Birth of young
Grass snake
Hibernation
Adult activity
Mating
Egg-laying
Egg hatching
Smooth snake
Hibernation
Adult activity
Mating
Birth of young
Data from more than one source
Key:
The degree of shading indicates the proportions of animals involved in each behaviour/activity.
The majority of animals will be undertaking this behaviour/activity
A proportion of animals will be undertaking this behaviour/activity
Note: The various active periods and activities could extend up to a month earlier and later in the southern-most counties of England. The reverse could be true in the far north or at altitude,
particularly associated with extreme weather.
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CHAPTER 5 REPTILE HABITAT
5.1
HABITAT ASSOCIATIONS/REQUIREMENTS
The six reptile species found in the UK exhibit a range of broad habitat associations. For ease
of interpretation, these general habitat requirements have been described by reference to
habitat types identified in the UKBAP, overseeing organisations’ BAPs and Phase 1 habitat
survey categories (see Annex I, ‘Further Reading’).
Table 5.2 summarises the habitat types in which the native British reptiles tend to be found
and gives an indication of their relative importance to the different species. Generally, across
different habitats, as structural and micro-topographic diversity increases, so the value of the
habitat or feature for reptiles becomes greater.
5.2
REPTILE-SPECIFIC HABITAT REQUIREMENTS
Although the individual species have particular habitat requirements, all reptiles are
constrained by their biology to occupy habitats which contain combinations of certain key
features. The most important features include:
l Basking sites: often on south facing slopes with a structurally diverse mosaic of
vegetation, substrates and micro-topography, providing a variety of micro-climates
between which they can move to regulate their body temperature;
tend to range over larger areas (up to 4 km from their hibernation sites) and to move from site
to site with greater frequency and rapidity.
5.3
REPTILE HABITAT ON THE SOFT ESTATE
There are a number of factors which make the existing roadside landscape suitable for
reptiles. Indeed, in some areas the existing soft estate tends to be more suitable for reptiles
than the surrounding countryside. The most important features tend to be as follows:
l Aspect and topographic variation: Many road verges form banks or cuttings which
provide good quality basking sites (particularly on the south-facing slopes).
l Micro-topographic variation: In many places, road verges tend also to incorporate a large
degree of small-scale variation in topography associated, for example, with dry ditches or
artificial bunds.
l Exposed substrates: A variety of structures and materials, often associated with these
slopes, for example mulch mats, metal covers, artificial hard surfaces, and rocky
exposures, can create a range of suitable basking spots.
l Refuges and hibernacula: Roadside banks tend to be free draining, and often incorporate
‘french drains’ and other structures which represent ideal refuges or hibernacula.
l Foraging areas: areas which contain relatively high concentrations of prey species, these
areas will generally also encompass a range of basking sites and refuges;
l Structurally diverse vegetation: Areas of landscape planting, particularly in the earlier
stages, often create structurally diverse habitats which provide cover and a degree of
micro-climatic variation. However, as they mature, unmanaged planting areas can shade
out the more valuable earlier seral stages. In addition, large uniform mown areas are also
less valuable.
l Hibernacula: free-draining structures, often in south facing banks, in which to hibernate,
such as disused mammal burrows, rock fissures, piles of logs or rubble and subterranean
structures; and
l Lack of disturbance: The lack of direct disturbance from humans (particularly where
pedestrians are discouraged or prohibited, such as within central reservations) tends to
promote the development of stable populations.
l Egg laying sites (for some species): for example, piles of rotting vegetation for grass
snakes, and loose, sandy ground for sand lizards.
l High densities of prey species: Roadside habitats often support substantial densities of
prey species, for example, short-tailed voles (Microtus agrestis) or lizards themselves (for
adders and smooth snakes).
l Refuges: places of shelter such as dense scrub, rock, logs, tree roots and subterranean
structures;
Reptile home ranges, and their ranges of movement to and from hibernation sites, tend to vary
significantly between species, age classes and with habitat structure and suitability. Slowworms, in particular, do not range over substantial areas nor far from their hibernation sites.
Individual home ranges can be measured in 10s or the low 100s of square metres. Common
and sand lizards tend also to occupy relatively modest but more variable home ranges (the
home ranges of sand lizards tend to be larger and more variable in size). Adders have been
recorded as migrating in the order of 0.5 – 1 km from their hibernation sites, but in many other
situations have been found to remain within much more circumscribed areas. Similarly, in
many situations, smooth snakes have been recorded as relatively sedentary. Grass snakes
MAY 2005
l Habitat corridors: The linear nature of roadside habitat creates a network of habitat
corridors, which may provide means for reptile dispersal, and link otherwise isolated
reptile sites.
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Acid grassland
Neutral grassland
B2
Neutral grassland
Calcareous grassland
B3
Calcareous grassland
Improved grassland
B4
Improved grassland
Habitats which do not fall within UK BAP Broad Habitats
H 8.4 Coastal grassland
Dwarf shrub heath
D1
Dry dwarf shrub heath
D2
Wet dwarf shrub heath
Habitats which do not fall within UK BAP Broad Habitats
D5
Dry heath/acid grassland mosaic
D6
Wet heath/acid grassland mosaic
Smooth
Snake
Boundaries
B1
Grass
Snake
J2
Acid grasslands
Adder
Boundary and linear features
Slowworm
Phase 1 Habitat Survey
Sand
Lizard
UK BAP Broad Habitats
Common
Lizard
Table 5.2 Habitat types with which British reptile species are associated
H 8.5 Coastal heath
C1
Bracken
Bogs
E1
Bog
Fens, marsh and swamps
E3
Fen
B5
Marshy grassland
F1
Swamp
G2
Running water
Standing open water and canals
G1
Standing water
Broadleaved, mixed and yew woodland
A 1.1 Broad-leaved woodland
Rivers and streams
A 1.3 Mixed woodland
Coniferous woodland
A 1.2 Coniferous woodland
Habitats which do not fall within UK BAP Broad Habitats
A2
Scrub
Arable and horticulture
J1
Arable land
Inland rock
I
Rock exposure and waste
Habitats which do not fall within UK BAP Broad Habitats
J 1.2 Amenity grassland
J3
Built-up areas
J 1.4 Introduced scrub
H6
Key:
MAY 2005
Important habitat
Sand dune
Habitat of moderate importance
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General
Although bracken appears as an important component within habitats for some species,
extensive growths of bracken which dominate a habitat through excessive shading can create
less valuable conditions.
Arable field margins can also be important for several species, particularly within
predominantly arable landscapes. These contribute to the levels of importance accorded to
the ‘Boundary features’ and ‘Arable Land’ categories.
The more open woodland and scrub habitats will be more important, and adders can be
present at relatively high densities in open areas or margins of coniferous woodland in
particular. Woodland habitats are also often important as hibernation sites for this species.
Grass snake
The more open woodland and scrub habitats will be more important, and this species can also
be present in large numbers on some dry heaths.
Smooth snake
Common Lizard
The categories indicated as ‘important’ are restricted to lowland examples of these habitats.
Some examples of fen, swamp and marshy grassland can represent more important habitats
for this species.
The more open woodland and scrub habitats will be more important, and common lizards can
be present at relatively high densities in open areas or margins of coniferous woodland in
particular.
The importance of boundary features along the margins of coniferous woodlands or large
stands of bracken, for example, will depend upon their juxtaposition with the more valuable
habitats.
Dry stone walls can represent particularly important habitat features for common lizards.
Sand Lizard
The categories indicated as important are restricted to lowland examples of these habitats.
Each of the categories indicated as of ‘moderate importance’ are only likely to be used by
sand lizards if they are adjacent to the more important, sandy heathland/sand dune habitat
types.
Slow-worm
Some of the wet heath/grassland habitats, particularly where these comprise rank grassland,
and certain kinds of built-up areas can also represent more important features for this species.
Adder
The importance of boundary features and areas of bracken, for example, will depend upon
their juxtaposition with other valuable habitats.
Some examples of fen, swamp and marshy grassland; coastal grassland; and occasionally
built-up land (for example derelict post-industrial sites) can support significant adder
populations.
MAY 2005
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6.1
INTRODUCTION
All survey techniques for reptiles are selective (to a greater or lesser degree) and the most
appropriate technique(s) will be determined by the information required and the species likely
to be present.
The principal survey techniques are set out below and their application with regard to new
schemes and the existing road network is described in the following sections.
A ‘decision matrix’ is presented in Annex G, which summarises the surveys appropriate at the
different stages of scheme assessment (as set out in DMRB Volume 11, ‘Environmental
Assessment’), the situations in which they should be employed and the points at which
‘different’ options for mitigation should be considered.
In general, reptile surveys need to combine conditions where reptiles are active but also
where they are likely to be seen. Thus the optimum periods are usually not when the reptiles
are most active and mobile, but when they are ‘warming-up’. The principle constraints on the
effectiveness of such surveys are that the colouration, markings and behaviour of reptiles
make them difficult to observe and that they seek to warm up as quickly as possible and
attempt to maintain an optimum body temperature. It is important therefore to bear in mind the
temperatures at which the different species bask and the body temperatures they are
attempting to reach, and compare these with the patterns of daytime ambient temperatures
during which the surveys will proceed. Clearly, therefore, the timing of surveys is critical and
this will vary through the season. The current, and preceding, climatic conditions are also key
variables.
6.2
SURVEY TECHNIQUES AND RECOMMENDATIONS
6.2.1
DIRECT OBSERVATION
This technique relies upon the observation and identification of basking animals. The
identification and interpretation of suitable reptile habitat and particular habitat features (see
Chapter 5, ‘Reptile Habitat’) is important, since predicting where basking animals are likely to
be found is one of the keys to carrying out a successful survey.
Inter-site comparisons using direct observation-based surveys will generally require the use of
transect methodologies as opposed to less structured searching of all suitable habitat
features. This has the disadvantage of producing fewer sightings, and may require a
corresponding increase in the number of visits necessary to produce robust results. The
transects also still need to be biased toward ‘hot spots’ (where basking reptiles are most likely
to be seen). Quantitative surveys of reptiles by direct observation generally relies on using
standard methodologies wherever possible and counting individuals seen per survey visit,
subsequently standardising the results further on the basis of the duration of the survey visits.
MAY 2005
Given the difficulties in reliably locating many reptile species/age classes by direct
observation, it is important to use skilled, experienced surveyors for observation-based
surveys.
6.2.2
THE USE OF ARTIFICIAL REFUGES
Rationale
This survey technique utilises the propensity for reptiles routinely to seek out structures that
both act as places of shelter from predation or disturbance, and as aids in absorbing heat.
They tend to use structures within their environment that heat up quickly and/or retain heat
throughout the day. By distributing a number of artificial refuges (also known by other terms,
see Annex C), it is possible to make use of this behaviour to find basking reptiles. Animals are
most often found sheltering and basking beneath artificial refuges, but some species (common
lizards and adders in particular) often bask on top of these structures. Reptiles can then be
identified and recorded by checking the artificial refuges regularly. Artificial refuges can also
form the basis for a quantitative survey method, and be used as a means of collecting animals
for translocation.
Materials
Sheets of corrugated metal, rubber, roofing felt, carpet and hardboard have all been used as
artificial refuges. Roofing felt, heavy-gauge rubber and corrugated metal tend to be the most
effective, although some studies have indicated that different materials may attract certain
species or age classes preferentially (this may also vary depending upon the situation in which
they are used). Some practitioners have recorded a preference for corrugated metal over all
other materials. On sites where disturbance by members of the public is likely, well-concealed
or less obtrusive materials are appropriate. Where disturbance is recorded, the use of artificial
refuges may have to be discontinued. There may also be constraints associated with the
potential trampling of artificial refuges by livestock. In both situations the survey
methodologies need to be designed in such a way as to protect the welfare of the reptiles
which may be using the artificial refuges (and any livestock).
The appropriate material to use as artificial refuges beside operational roads is a heavyweight
flame-activated bitumen roofing felt. This is sufficiently heavy and flexible that it is not blown
up by the draught of passing vehicles. Other lighter and/or stiffer materials (corrugated metal
for example) may pose a hazard to road users when placed adjacent to the carriageway.
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Table 6.1
The effectiveness of direct observation vs artificial refuge surveys for each of
the different reptile species
Size
The recommended minimum size for artificial refuges is 0.5m2, however some practitioners
have recorded the preference by snakes of larger refuges, so in most cases a range of refuge
sizes should be used, including some larger sheets. The appropriate number, density and
distribution of artificial refuges will vary with the aims of the survey and configuration of
different habitat features, etc. (see Sections 6.3.3 and 6.4.3).
Species
Survey Method
Direct Observation
Artificial Refuges
Slow-worm
Location
Common lizard*
Artificial refuges should be placed in habitats and positions most likely to be used by basking
and foraging reptiles. They should be placed on top of short or flattened vegetation; not on
bare ground nor supported by vegetation too far above the ground surface. Setting artificial
refuges in this way allows temperature gradients and a degree of humidity to develop beneath
them, and provides reptiles with a more appropriate shelter. The artificial refuges should also
be distributed in a range of aspects and shade conditions, with most placed in south-facing
locations and partially overhung by vegetation, against habitat features or vegetation which
provide dense cover. Captures from beneath artificial refuges tend to increase with time, so
they should be established for at least a week before being used to collect survey data.
Experience
Sand lizard
Grass snake
Adder **
Smooth snake
Key:
Generally not suitable ***
As with direct observation-based surveys, experienced surveyors are also needed to design
and supervise the location of artificial refuges for a refuge-based survey, and to capture the
animals effectively (although the situations within which reptiles need to be handled should be
minimised, and this should only be done where specific information is required). There are
also health and safety considerations associated with handling venomous reptiles and welfare
considerations (for the reptiles) when handling all lizards and snakes. This reinforces the need
to use experienced field staff.
MAY 2005
➤
In practice, the most effective approach is to combine direct observation and artificial refugebased surveys. However, under these circumstances it is very important that an appropriate
amount of effort is put into searching for reptiles whilst moving between artificial refuges and
that all suitable basking spots, etc., are inspected rather than simply moving from artificial
refuge to artificial refuge, following the shortest/easiest route. All surveys should also
incorporate checks beneath any natural or pre-existing artificial refuges, which should be
carefully returned to their original postion once inspected. In addition, it is important to vary the
route taken and the sequence of artificial refuges to be checked, and the times at which the
surveys are carried out. Depending upon the density of the vegetation involved, some
advance preparation, for example clearing paths or spaces for artificial refuges may be
appropriate, but these would need to be carried out in such a way as to minimise the
possibility of harming reptiles in the process.
➤
COMBINATION SURVEYS
Increasing suitability
➤
6.2.3
Not suitable
Notes: This table is intended, in particular, to indicate the particular issues involved in using
these techniques in the context of road verges.
*
In these situations it is often important to provide common lizards with artificial basking
sites; the effectiveness of artificial refuges therefore reflects observations of basking
animals on top of refuges as well as underneath them.
**
For adders in particular, juvenile and sub-adult animals tend to be more frequently
encountered under artificial refuges. Adults tend to be more effectively surveyed by direct
observation.
***
Only suitable in some circumstances and/or only by particularly skilled surveyors.
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6.2.4
OTHER SURVEY TECHNIQUES
There are no other effective field survey techniques that are appropriate for the routine survey
of reptiles in this context. Drift fencing and pitfall trapping are not recommended given their
labour-intensive nature and on welfare grounds. Additional field signs can provide sporadic
additional information: examples of these include finding sloughed skins (often found beneath
refuges; the species to which the skin belongs can often still be identified); occupied egg
laying sites, and ‘egg scrapes’ (test holes created by sand lizards prior to egg-laying); and
burrows created by sand lizards in sandy banks. ‘Nooses’ are sometimes used to catch
individual lizards (particularly sand lizards) but these should only be used by skilled
practitioners.
6.2.5
SEASONAL, CLIMATIC AND TIMING CONSTRAINTS
With both techniques, the timing of surveys (in terms of time of day and season) and
prevailing weather conditions are crucial to survey success.
6.2.5.1 Seasonal constraints
In general, the best months during which reliably to find reptiles are April to mid-/late-May, and
mid-/late-August to mid-/late-September, depending upon the weather conditions at the
beginning and end of each period.
6.2.5.2 Timing constraints
The most appropriate times within which to survey will depend upon temperature, sunshine,
rainfall and other weather parameters. Generally, in these months, the best times of day are
between 0830 and 1100, and between 1600 and 1830. Very early or late in the year, the
middle part of the day will be more productive, whereas during the hotter parts of the year,
reptiles will be found basking earlier and earlier. Between June and mid-August there can be a
very narrow ‘window’, early in the morning, and again in the later, cooler part of the day, within
which either kind of survey is effective.
6.2.5.4 Weather conditions
Generally, hazy or intermittent sunshine provide the most productive conditions, but bright
sunshine early in the day in cool weather can also be suitable. Heavy rain or strong wind
makes direct observation, in particular, impractical and unsuccessful. Weather patterns can
also be important: reptiles recorded by direct observation and, to a lesser extent, captures
from beneath artificial refuges, tend to increase during warm weather following a period of
colder conditions, or following rain showers. Thus the preceding weather conditions are
important; periods of sunshine after rain tend to be important triggers for increased reptile
activity.
6.3
SURVEYS FOR NEW ROAD SCHEMES
6.3.1
ASSESSMENT STAGE 1
6.3.1.1 Desk study
As part of the Stage 1 Desk Study, relevant organisations (listed in Annex E) should be
contacted for any information that they may hold on reptiles in the vicinity of the proposed
route corridor options. In addition to the specialist groups listed in Annex E, information on
reptiles can be obtained via requests to, or consultations with, other organisations which
routinely hold relevant ecological information. These would typically include the Statutory
Nature Conservation Organisations, Local Authorities, Wildlife Trusts and Local Biological
Records Centres.
Desk studies of this kind would be expected to provide information on sites of known
importance for reptiles, and past records of reptiles within the area, but the quality and
completeness of the information will be highly variable. It is extremely unlikely that a desk
study alone will ever provide information on all of the habitats or features of value to reptiles in
a given area. However, the majority of sites likely to contain the two rarer species (sand lizards
and smooth snakes) should certainly be revealed.
6.3.1.2 Map-based habitat assessment
6.2.5.3 Temperature conditions
When the air temperature exceeds 18 oC many reptiles may not be found basking at all and
surveys, particularly using refuges, will be unreliable. Surveys will be most effective when the
air temperature is between 9 and 18 oC.
MAY 2005
Maps and aerial photographs should be studied in order to highlight those habitats likely to be
of value to reptile populations which may be affected by different route options. Particular
habitat ‘triggers’ are the presence of heathland, sand dunes, scrub, woodland, unmanaged
grassland and wetland features, and the avoidance of these should be considered in route
option or alignment choice. The aspect of different features may also provide an indication as
to their suitability for reptiles, but a map-based assessment will not reveal details of microtopography, or habitat-structure.
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6.3.1.3 Assessing the importance of the Stage 1 information
Sites should be assessed as a potential constraint, at Stage 1, and avoided where possible, if
the desk study highlights that the site contains (or has contained) rare reptile species, good
assemblages of the more common species, or species on the edge of their geographical
range. In Britain this means:
l any records of sand lizard or smooth snake or suitable habitat within their known range;
l sites with good quality habitats for reptiles and records of at least 3 reptile species;
l sites known to contain reptile species that are otherwise uncommon in the locality, or
near the edge of their known range.
6.3.2
ASSESSMENT STAGE 2
6.3.2.1 Desk study
Depending upon the results of the Stage 1 assessment and the results of the Stage 2 fieldwork
set out below, it may be appropriate to update and/or extend the desk study information.
In addition, building on the map-based assessment at Stage 1, a more detailed investigation is
often helpful prior to fieldwork at Stage 2: maps and aerial photographs provide a simple
means of putting the proposed route corridor in context with regard to its surrounding habitats.
The opportunities for animals to travel between affected areas and other suitable habitats
using ‘habitat corridors’ can often also be assessed in this way.
6.3.2.2 Field surveys
Given their widespread distribution, virtually any new scheme or improvement could have
potential impacts on the more common reptiles (i.e. common lizard, slow-worm, adder and
grass snake. However, given that (a) it is usually possible to predict the likely occurrence of
reptiles on the basis of the habitats present, and (b) in most cases options for mitigation are
straightforward, it is rarely appropriate to undertake specific surveys for the more common
reptile species (i.e. all those except sand lizards and smooth snakes) at Stage 2.
What is generally more appropriate is to incorporate an assessment of the likely presence of
reptiles in different parts of the route corridor, within the walkover survey that should routinely
be carried out at Stage 2. The intention of this initial survey should be to gain a better
understanding of the ecological constraints associated with different route options; this
routinely involves habitat mapping and walkover surveys for protected species. Although the
extent of these surveys will vary, they should routinely include (for reptiles): an assessment of
the likely presence of the different reptile species; the likely value, importance and functional
MAY 2005
significance of the habitat features (for example potentially suitable hibernation sites, egglaying sites etc.); and if the timing of the survey and weather conditions allow, incidental
observations of the animals themselves.
The intention should be to inspect the length of the scheme at this stage, and for it then to be
possible to restrict Stage 3 reptile surveys to selected habitats, features or locations. It is
generally appropriate that a small multi-disciplinary team be used for these Stage 2 walkover
surveys, including staff competent to identify the different reptile species, interpret the
importance and functional significance of different, often subtle, habitat features and to scope
all subsequent investigations.
As identified above, the likely presence of smooth snakes or sand lizards will normally be
highlighted during the desk studies. However, if a feature is identified which could support
these species but no records exist, because of the potential importance of the constraint,
consideration should be given, in consultation with the SNCO (and where relevant, expert
NGO, for example the Herpetological Conservation Trust and local Amphibian and Reptile
Groups (ARGs)), to undertaking specific, targeted surveys to confirm the presence or absence
of these species at Stage 2.
6.3.3
ASSESSMENT STAGE 3
6.3.3.1 Scope of the Stage 3 surveys
In general, the scope of detailed reptile surveys at Stage 3 should reflect the likely magnitude
of any predicted impacts and the likely importance of the reptile population(s). In the following
circumstances it is usually appropriate to undertake routine reptile surveys:
l if the presence of the more common species has not been confirmed by desk study or
incidental observations during the Stage 2 walkover; and/or
l if the habitat information suggests the possible presence of substantial reptile populations
or a diverse assemblage of reptiles (three or more species), upon which the new road
may have a significant impact.
Routine surveys
It will rarely be necessary to undertake detailed population estimates for the more common
species, and the aims of these routine surveys should be to investigate:
l the presence or absence of reptiles;
l the presence or absence of each of the different reptile species (reptile assemblage);
l the distribution of reptiles within and around the site in question;
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l the apparent viability of the reptile population(s) based on, for example, evidence of
breeding in current or recent seasons and the apparent proportions of animals carrying
wounds/with lost tails (for lizards);
l the identification of potentially important features (potential hibernation sites for example);
l an assessment of the likely value of the different habitats for reptiles; and
l whether more detailed reptile surveys would be required.
It may also (in future) be useful to assign each reptile population to a ‘population size class’ in
order to compare sites, and assess the significance of impacts upon them. Research is being
undertaken by English Nature into the feasibility of estimating population size class categories
for reptiles in the UK.
In combination with the results of the desk study, these routine surveys should help put the
population(s) into some local context, wherever possible. However, there are few reliable
baseline datasets concerning reptile density and distribution in different counties and between
different sites, and thus the results of the Stage 3 surveys for common species may be more
relevant to comparisons between sites along a single scheme, within which exactly
comparable surveys can be undertaken. Similarly there is little existing guidance on the
significance of reptile survey results: The ‘best sites supporting at least three of the four
widespread species’ are eligible for SSSI notification, along with all established populations of
smooth snakes and sand lizards (the only ‘important’ populations of these species are in
Dorset). ‘Key Reptile Sites’ have been defined as those supporting three or more reptile
species, two snake species, large populations of one or more species, or populations of
species which are clearly uncommon in the locality or region.
In most cases for these routine surveys, the appraisal of the conservation status of the reptile
population(s) involved should be made on the basis of:
l the assemblage of reptiles revealed by the survey;
l the apparent health and productivity of the population(s);
l the size quality of the habitat features; and
l the functional significance of different habitat features,
supplemented where appropriate by an expert assessment of the capture data.
If the habitat information suggests the presence of no more than marginally important
populations of common species, that impacts would be minimal and/or there is insufficient
time to complete a survey, it may be more appropriate simply to assume the presence of
reptiles, and design and implement precautionary mitigation.
More detailed surveys
Where potential impacts on sand lizards or smooth snakes have been identified, it is
necessary to undertake comprehensive surveys at this stage in order to fully investigate any
possible effects. In contrast to routine surveys of the more common species, this may include
as effective an assessment of population size as possible. The parameters of such a survey
should be decided in consultation with the SNCO.
Similarly, if the Stage 2 (desk study and field survey) and initial Stage 3 surveys indicate that
the new road may have a substantial impact on a particularly important population of the more
common reptile species, (for example a population likely to be important on a county or
regional basis), or a key feature for the local reptile population (for example communal
hibernation site), then more detailed surveys may also be required. These may include
extending the survey period to cover key seasons and/or more detailed surveys to investigate
the function and importance of particular features or off-site areas. As with the more detailed
surveys of sand lizards and smooth snakes, the scope of any further surveys that may be
necessary should be discussed with the SNCO.
6.3.3.2 Routine Stage 3 survey methodology
Whereas it has been possible to define a relatively precise methodology and sampling regime
for surveys of existing roads (see section 6.4.3, ‘Targeted general reptile surveys’), it is more
difficult to be prescriptive with regard to new schemes. This is largely because the most
appropriate survey design will depend upon the type and configuration of habitats that the
scheme would affect. Nevertheless, the following guidance is intended to help inform survey
design:
Survey technique
Investigations should be based upon a combination direct observation and artificial refugebased surveys.
Given that an estimate of absolute population size will not have been made for the more
common species (as discussed in Chapter 10), for the purposes of mitigation measures, for
example, involving the translocation of reptiles, it is preferable simply to assume that
populations of reptiles are at carrying capacity for the particular habitat involved, and design
relocation operations and make provision for receptor sites accordingly.
MAY 2005
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Refuge density
Reviewing the scope and targets of the survey
A density of no fewer than 10 artificial refuges per hectare should be used, with greater
concentrations around key habitat features and within ‘problem’ habitats (for example areas
with a large number of natural refuges which cannot themselves be checked). The distribution
of artificial refuges will depend upon the spatial configuration of the habitat, but in some areas
it will be appropriate to deploy an equivalent density of up to 50 artificial refuges per hectare.
It is important to retain flexibility and to be reactive with regard to survey design. If, for
example, the initial results of the Stage 3 surveys indicate the need for a more detailed
investigation (for example adders are recorded in an area where they are thought to be
uncommon, in numbers which suggest the site may be important on a county or regional
basis), then it would be necessary to review the scope and target of the surveys as early as
possible in the season in order to avoid delays.
Refuge type
Refining the habitat assessment
It is generally appropriate to employ a majority of either corrugated metal, heavy-weight
roofing felt or thick rubber refuges, but also to include a variety of materials to help increase
the range of captures as far as possible. Further design and recommendations of use are
presented in Annex C, ‘Artificial Refuge Specification’.
In parallel with the reptile survey work, the habitat appraisal (for reptiles) undertaken during
Stage 2 should be augmented during the routine Stage 3 survey, with the aim of refining an
assessment of the likely impacts of the scheme, and the scope and design of mitigation.
Refuge establishment
The need for additional investigations
The artificial refuges should be established for a minimum of a week before the first
inspection.
Some published guidance has suggested increasing the number of visits to 20 or more in an
attempt to gain a better impression of relative population size and to help identify key areas.
However, for the purposes of impact assessment and mitigation design, it is recommended
that, where further information is thought to be required, a clear decision is made either to
design appropriately targeted follow-up surveys on a case-by-case basis (see below).
Otherwise, for the more general purposes of the Stage 3 assessment, the protocol described
above should reveal sufficient information.
Inspection protocol – during the optimum seasons
A minimum of five inspections should be undertaken under suitable weather conditions and at
suitable times of day. The visits should be spread over the periods April to mid-/late-May
and/or mid-/late-August to mid-/late-September (see Section 6.2.5). Each inspection should be
undertaken on a separate day. How the visits are structured and whether they comprise both
morning and late-afternoon checks will depend upon the season, climatic constraints, the size,
complexity and ‘difficultly’ of the site, and a range of other factors. The over-arching aim
should be to maximize the likelihood of finding reptiles on each inspection.
6.3.3.3 More detailed Stage 3 surveys
Given the reactive nature of these surveys, it is not appropriate to include all possible
specifications within the scope of this Advice Note. However, it is appropriate to give some
guidance:
Inspection protocol – outside the optimum seasons
Population estimates
If it is not possible to undertake all of the visits within one or other of these seasonal ‘windows’,
then the minimum number of visits needs to be extended to ten (all of which still need to be
carried out under suitable conditions between April and September), still with as many visits as
possible within the key periods. Furthermore if, even after five survey visits at the ‘right’ time of
year, some doubt exists over the findings of the survey (for example a species previously
recorded at a location appears to be absent, or if there are an unusually large number of
negative results), then the survey should also be extended to include ten visits.
MAY 2005
There are welfare considerations associated with repeated handling of reptiles and other
intrusive techniques. The use of these as part of any Stage 3 surveys should also be avoided
unless absolutely necessary. Estimating population sizes or densities with any degree of
accuracy or reliability will always be problematic and requires considerable expertise. It will be
necessary to sample a relatively large proportion of a resident population in order to estimate
population sizes accurately and this will be most difficult for common lizards, and slow-worms
in particular. However, in the vast majority of cases, such information will not be required for
these species. Given the large survey effort necessary for population estimates to be made for
any species, this should be restricted to those situations where, on the basis of the magnitude
of the predicted impacts and the importance of the population, it is clearly warranted.
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CHAPTER 6 REPTILE SURVEY METHODS
Where these are necessary, population estimates will generally require that animals are either
marked or recognised individually. For most reptiles reliable individual recognition is possible
for the adults. For snakes, individual recognition is usually possible on the basis of a mixture
of colour markings, head scale patterns, and ventral scale counts; in addition, ventral scale
clipping and the use of subcutaneously injected transponder tags (PIT tags) are possible.
Slow-worms can be recognised individually by a combination of head markings and chin spots
(simple body size measurements are also helpful). Adult sand lizards can be distinguished
reasonably accurately on the basis of their dorsal markings, whereas adult common lizards
are best differentiated on the basis of their belly markings, particularly the patterning on the
anal scale. Juvenile common lizards are impossible to recognise individually without marking
and shed their skins so regularly that surface marks do not persist (however, it will rarely, if
ever, be necessary to recognise individual juvenile common lizards).
Investigations of potential receptor sites
Investigations of key features
It is difficult to give generic advice, since the appropriate corridor width will vary, both within
and between schemes, depending upon the configuration of the habitats and the species likely
to be encountered.
This will generally involve extending the survey season and/or intensifying the survey effort in
order to confirm the importance of selected areas or features. These are likely to include:
l communal hibernation sites (often indicated by aggregations of animals before and after
hibernation, particularly relevant for adders);
l egg laying sites (indicated by, in the case of grass snakes, the structures themselves, or
for sand lizards, either ‘egg scrapes’ and large aggregations of new hatchlings; and
l favoured feeding areas (often indicated by regular captures of adult animals during the
middle part of the year).
Investigations of off-site areas
These are to some extent self-explanatory and will be most relevant where the site in question
is part of a larger ecological unit. This could be, for example, if the site were to be part of a
linear feature such as a disused railway line, where loss of habitat could fragment an
otherwise valuable habitat corridor.
Investigations into the seasonal use of sites or seasonal distribution within a site
In certain situations some reptile species, snakes in particular, are thought to migrate between
habitat features which provide suitable foraging conditions in the summer and those (perhaps
more freely drained areas) which provide suitable hibernacula, later in the year. In addition,
some reptiles may move into particular areas to take advantage of seasonally abundant prey
species. If, on the basis of the initial habitat surveys and assessment, and the routine reptilespecific surveys (and, perhaps, surveys beyond the site boundaries to help put the site in
question in context (see above)) the site appears likely to be seasonally important, then further
surveys at the critical time of year may be appropriate.
MAY 2005
In the context of a reptile translocation operation (see Section 10.2.4.3), it is necessary to
identify and assess the suitability of potential receptor sites. A similar approach should be
taken to surveying these sites, involving a habitat assessment and collecting the basic survey
information set out above. However, in addition, consideration needs to be given to whether
any reptile populations found are likely to be at carrying capacity for that habitat (potential
receptor sites are often chosen where relatively new habitat features have been created or
remedial management has taken place and thus populations may be below carrying capacity),
and what opportunities might exist to enhance the habitats for reptiles.
6.3.4
SURVEY CORRIDORS
It is also inappropriate to set a single, rigid survey corridor for the multidisciplinary Stage 2
walkover, since the different elements of the survey will require different corridor widths
(depending upon the habitats/features and survey results).
With regard to more detailed surveys, the majority of effects on reptiles will be associated with
the footprint of the road itself. However, it may be necessary also to consider: areas which
could be subject to indirect (for example hydrological) effects; key features remote from the
route which could be isolated by road construction; and features that would be severed along
which reptiles may move.
Surveys should therefore be extended beyond the route corridor where appropriate, but only
as far as necessary to address the specific questions, with regard to impacts and mitigation,
that the survey is attempting to answer.
6.3.5
OTHER INVESTIGATIONS
In certain critical situations it may be necessary to employ more sophisticated investigation
techniques such as radio-tracking, to confirm the importance of particular areas, but this will
be extremely uncommon; any details will be site- and species-specific and are beyond the
scope of this Advice Note.
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CHAPTER 6 REPTILE SURVEY METHODS
6.4
SURVEYS FOR THE EXISTING ROAD NETWORK
In advance of undertaking maintenance works which could affect reptiles, it may be necessary
to undertake surveys to confirm the presence or absence of the different reptile species (if this
is not already known), to estimate the likely impacts upon them and to help design mitigation.
Once again, it is necessary that the scope of any such surveys are proportional to the likely
scale of impact and importance of the reptile population.
6.4.1
DESK STUDY
Appropriate environmental databases of the highway network should be consulted for
information on habitats and the presence of reptiles in the vicinity of the works. However, given
that reptile records tend to be ‘patchy’ across the road network, and that new records both
from within the soft estate and surrounding areas will constantly be being compiled, it is also
necessary to request information from a similar list of consultees as is indicated in Annex E
(some may be more locally applicable than others).
At this stage, any available information on the local status of the different reptile species
should also be collated, in order to help put future survey information in context.
6.4.2
HABITAT INVESTIGATION
Depending upon the results of the Desk Study, it may be appropriate to undertake a brief
inspection of the road verges, with the aim of collecting a similar level of information as for the
Stage 2 assessment of a new scheme. Once again, it will be necessary to use staff competent
to interpret the importance and functional significance of the habitat features, to scope any
subsequent investigations that may be required, and to design appropriate mitigation.
6.4.3
ROUTINE REPTILE SURVEYS
Whether or not further reptile surveys are required will then depend upon the results of these
initial stages. Under the following circumstances, no further surveys would be required, and it
would simply be appropriate to design and implement precautionary mitigation:
l if reptiles are already known to use the verge(s) in question;
l no additional species would be expected;
l no key habitat features have been identified;
l neither a particularly large nor locally important population, nor diverse assemblage
would be affected;
l neither sand lizards nor smooth snakes would be involved; and
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It is often difficult to determine the local importance of a given population. However, in certain
parts of the UK, slow-worms and adders, for example, are known to be uncommon, and in
these situations a section of road verge which supports a substantial population would be
considered important.
If, however, further information on the presence or absence, distribution and (approximate)
relative density of reptiles is required, then the following protocol would be appropriate:
Survey technique
As with the routine Stage 3 surveys for new schemes, the best approach is a ‘combination’
direct observation and refuge-based survey.
Distribution and density of refuges
The most efficient surveying/sampling methodology involves the placement of 50 artificial
refuges on each verge, usually following a ‘staggered’ transect line, with each refuge located
in the most appropriate situation for use by reptiles and with the refuges placed in a variety of
shade conditions, at approximately 10 metre intervals; i.e., 100 artificial refuges distributed
over a length of approximately 500 metres of road.
Refuge type
In contrast to surveys away from ‘live’ roads, the artificial refuges used should comprise
largely 0.5 m2 sheets of heavy-weight flame-activated bitumen roofing felt, with some panels
cut larger to increase the reliability of detecting some snakes. This heavy, flexible material
follows the contours of the ground and is not ‘blown-up’ by passing traffic, even if located close
to the edge of the carriageway.
Inspection protocol
The artificial refuges then need to be checked and the transect line inspected for reptiles using
the same protocol as set out in Section 6.3.3.2 (above).
Varying the specification/sampling protocols
Clearly, it is possible to ‘stretch’ or ‘contract’ these specifications to fit an exhaustive survey of
a particular feature. The most efficient approach to surveying longer sections however is to
identify broadly similar verge habitats and to design a sampling protocol based around this
standard survey technique.
Practical implementation
Several practical issues will need to be considered; for example, it is best to choose sampling
locations with easy access to the verges from over-bridges and underpasses and safe parking
locations off the carriageway. A road safety risk assessment will need to be carried out in
conjunction with the Managing Agent’s (or equivalents’) Safety Advisors and all agreed
precautions included within a scheme- and location-specific survey plan. Appropriate Personal
l the options for mitigation are relatively straightforward.
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CHAPTER 6 REPTILE SURVEY METHODS
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Protective Equipment must be worn at all times and, given the hazards involved, not only
should the surveyors be skilled and experienced with regard to reptile surveys, but they must
also be familiar with working close to ‘live’ roads. Reptiles are known to use habitats within the
central reserve as well as adjoining verges. Whilst it is not often necessary to include the
central reserve as part of these surveys, the potential presence of reptiles there needs to be
considered for mitigation operations.
6.4.4
MORE DETAILED SURVEYS
If it is likely, on the basis of the desk study, habitat investigation or general reptile surveys, that
maintenance operations would affect either (a) sand lizards or smooth snakes; or (b) a
particularly important population (of the more common species) or key feature for the local
reptile population, then more detailed surveys may be required.
The scope, detail and methodologies for these surveys should follow the guidance in Section
6.3.3.3 (above). Again, these should be developed in consultation with the SNCO.
6.4.5
MONITORING REPTILES ON THE SOFT ESTATE
The survey technique described above also provides an appropriate basis for a system of
monitoring reptiles on road verges. This is dealt with in more detail in Chapter 12, ‘Monitoring’.
MAY 2005
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CHAPTER 7 WHEN ARE REPTILE SURVEYS NECESSARY?
7.1
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WHEN ARE SURVEYS NECESSARY FOR NEW SCHEMES?
Given the widespread and ‘patchy’ distribution of many of our native reptile species, every new
scheme will have to take account of its possible impacts on reptile populations. This will
almost certainly involve an assessment of the value and importance for reptiles of the habitats
that would be affected, as part of a combined habitats and protected species walkover survey.
Depending upon the likely importance of any reptile populations and the potential impacts of
the scheme upon them, further targeted reptile surveys may be appropriate. The requirements
for reptile surveys and assessments for new schemes are set out in Section 6.3.
7.2
WHEN ARE SURVEYS NECESSARY FOR THE EXISTING ROAD
NETWORK?
Since reptiles are also known to occur on road verges throughout the UK, and road verge
habitats can represent features of considerable value to reptiles, including the rarest species,
a range of maintenance operations could potentially affect reptile populations. For this reason,
almost all maintenance works and operations need to consider impacts on reptiles. Depending
upon whether existing information already exists and, as above, the scale of the possible
impacts, the importance of the reptile population(s) and the likely options for mitigation,
specific surveys may be required. The requirements for reptile surveys and assessments for
the existing road network are set out in Section 6.4.
Given the absence of reptile information in most environmental databases, opportunities
should be taken wherever possible to collect information on the status of reptiles throughout
the soft estate. In addition, across the road network, and in certain key locations in particular,
surveillance monitoring of reptile populations would also be appropriate. This is dealt with in
more detail in Chapter 12, ‘Monitoring’.
7.3
WHEN IS IT NECESSARY TO UPDATE REPTILE SURVEY
INFORMATION?
Whilst the results of many ecological surveys can become out-of-date relatively quickly, this is
generally not the case for reptiles. Once sites have been surveyed appropriately, and
particularly if they are found to support established reptile populations, their status is likely to
remain valid for several years, unless there are substantial changes to the habitats concerned.
Thus, in many cases, the appropriate means of updating the surveys can be a relatively brief
re-inspection of the habitats rather than a repeat of the original methodology. One exception to
this is where habitats are identified as suitable for reptiles but none are found, particularly if
there are known populations nearby. In these situations subsequent colonisation is a
possibility and surveys to confirm the presence or absence of reptiles should be repeated if
the original data are more than a year old.
MAY 2005
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CHAPTER 8 LICENSING CONSIDERATIONS AND QUALIFICATIONS FOR SURVEYORS
8.1
LICENSING CONSIDERATIONS FOR REPTILE SURVEYS
8.1.1
WHEN LICENCES ARE REQUIRED
A licence from the appropriate SNCO is required in order to disturb, capture or handle smooth
snakes and sand lizards for the purposes of carrying out a survey (a licence can be issued for
conservation or scientific purposes). It is therefore important that the relevant licence is
obtained, not only when the intention is to capture and handle the animals in question, but
also where the possibility of disturbance to individuals of these species exists; i.e. where a
reptile survey using artificial refuges is being carried out in suitable habitat within the known
range of these species.
8.1.2
WHEN LICENCES ARE NOT REQUIRED
A licence is not required to disturb, capture or handle reptile species other than smooth snake
and sand lizard. Therefore, where a reptile survey using artificial refuges is being carried out in
habitats not suitable for smooth snake and sand lizard or outside their known range, no
licence is required. Furthermore, reptile surveys which do not involve capture, disturbance or
handling of animals, such as ‘direct observation’, do not require a licence.
8.2
LICENSING REQUIREMENTS FOR MITIGATION WORKS
8.2.1
WHEN LICENCES ARE REQUIRED
Both sand lizard and smooth snake are protected under UK and European law, as
summarised in Section 3.1 and Annex A, ‘Review of Legislation and Guidance’. Therefore the
following activities should be carried out under licence to the Appropriate Authority (Defra in
England, or the Welsh Assembly Government in Wales):
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Licences for sand lizard and smooth snake will only be granted for works relating to road
schemes which are of overriding public concern or for health and safety reasons; where there
is no satisfactory alternative; and where the development will not be detrimental to the
maintenance of the population of the species concerned at a favourable conservation status in
their natural range. (See Annex A for further details.)
8.2.2
WHEN LICENCES ARE NOT REQUIRED
Licences are not required for works affecting the more common reptile species, i.e. adder,
grass snake, common lizard and slow-worm. None of these species are protected under
European legislation, and there is no provision for licensing developments under the Wildlife
and Countryside Act (1981), and amendments. However, in order to comply with legislation it
is important that the mitigation works for any scheme involving these species are designed in
accordance with the current best practice guidelines set out in this document. In addition, it is
recommended that the relevant SNCO be consulted and allowed a reasonable period in which
to provide advice should they consider it necessary.
8.3
QUALIFICATIONS AND EXPERTISE
Whilst surveys for the more common species of reptiles do not require a licence, and nor do
walkover surveys which do not involve the disturbance or handling of smooth snakes or sand
lizards, reptiles are generally well camouflaged and secretive, and their behaviour and
subsequent ‘observability’ is very weather dependent. It is therefore important that although
specific qualifications are not relevant, surveys are carried out by suitably experienced field
surveyors.
l any mitigation works which involve the disturbance, capture or handling of sand lizards or
smooth snakes, such as a translocation operation;
l any works which would entail the damage or destruction of a breeding site or resting
place of these species;
l works which would obstruct access to structures or places used by these species for
shelter and protection, such as the use of either temporary or permanent reptile-proof
fencing; or
l the potential for incidental disturbance of these species.
MAY 2005
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CHAPTER 9 POSSIBLE EFFECTS ON REPTILES
9.1
INTRODUCTION
There are many aspects of road construction and operation which can have potential impacts
on reptiles. These are described below in terms of the potential impacts on nature
conservation outlined in the DMRB (Vol. 11). In many cases, it will not be possible to
determine the precise significance of these impacts in the absence of relevant research, but
wherever possible the precautionary principle should be applied. As part of the Environmental
Assessment process, it will also be necessary to set out clearly the relationships between the
nature conservation importance of the reptile populations that might be affected, and the
magnitude of any predicted impacts upon them.
Whilst many of the issues dealt with below are potentially harmful to existing reptiles and
reptile populations, new roads and the management of the existing soft estate also present
considerable opportunities to enhance areas for reptiles, through modifying landforms, and
habitat creation and management.
9.2
NEW ROAD SCHEMES
9.2.1
DIRECT LOSS OF HABITAT THROUGH LAND-TAKE
Most new road schemes or improvements require a limited land-take in any one location
(compared to, for example, housing, business or leisure developments). They therefore tend
to involve fewer significant impacts with regard to habitat loss (for example, the removal of
suitable foraging habitat for reptiles). In addition, it is often possible to avoid impacts on
important features (hibernation sites, for example) by the early identification of these sensitive
sites and good engineering design. However, under certain circumstances, for example, where
potentially important habitat runs parallel and close to the road or where route alignment is
constrained by other features, there may be unavoidable impacts. Different reptiles show
strong preferences for particular habitat types and are sensitive to the loss of these features
(even where very small patches of habitat are lost), which can increase the significance of the
impacts. In addition, some key features (for example, communal hibernacula) can be
important to large numbers and successive generations of reptiles. Impacts on these features
can therefore have disproportionately significant effects. Depending upon the effectiveness of
any mitigation, there is also the potential for incidental disturbance, injury and mortality of
reptiles associated with habitat clearance.
9.2.2
juvenile or sub-adult dispersal (often in random directions) to colonise new habitats. However,
adult dispersal and short-distance range shifts can also be responsible for colonisation/recolonisation of available habitat nearby. Roads can form significant barriers to the movement
of reptiles and therefore, in addition to the potential impacts on reptiles of direct habitat loss,
the construction of new roads or improvements can cause fragmentation of reptile
populations. This could potentially prevent individuals from finding suitable hibernation sites or
foraging areas and may lead to the isolation of fragments of larger existing reptile populations.
9.2.3
ROAD TRAFFIC RELATED MORTALITY
Some reptile species tend to follow well-established route-ways (thought to be guided, in some
cases, by pheromonal cues) between key features (for example to and from hibernation sites),
which makes them potentially vulnerable to increases in mortality on new roads.
9.2.4
DISRUPTION TO LOCAL HYDROLOGY
Grass snakes are particularly associated with wetland features and several other reptile
species can be found in relatively large numbers in wetland habitats. It is for this reason that
road schemes which alter natural drainage patterns or disrupt local hydrology through, for
example, the installation of artificial drainage, could potentially destroy or degrade important
habitats for reptiles.
9.2.5
COLLATERAL HABITAT CREATION
Features such as new landscape planting, or the creation of south-facing embankments,
whilst not provided as mitigation specifically for reptiles, would be expected to be of benefit as
they become established. Certain measures can also be incorporated to maximise the value
of these features.
9.2.6
PUBLIC ACCESS
Once a new road is operational (and to some extent during the construction period), public
access and related activities can lead to the accidental degradation of reptile habitats (for
example, through uncontrolled fires).
SEVERANCE OF HABITAT
The range of movements routinely undertaken by reptiles varies considerably between
different species, life stages, populations and habitats in which they are found. Individuals of
some species tend to undertake regular seasonal migrations between hibernation sites and
summer feeding areas, and sometimes even more frequent movements between refuges and
favoured foraging locations. Others are far more sedentary. Most reptile species rely on
MAY 2005
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CHAPTER 9 POSSIBLE EFFECTS ON REPTILES
9.3
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THE EXISTING ROAD NETWORK
Many of the issues highlighted above for new roads and improvements are also relevant to the
existing road network.
9.3.1
ROAD TRAFFIC RELATED MORTALITY
As well as the ongoing mortality of animals attempting to continue to access hibernacula,
feeding sites etc., on either side of a road, some reptiles will become habituated to the traffic
disturbance, basking on hard surfaces very close to the carriageway and foraging routinely in
verge habitats. This can result in more regular crossing of the main line, slip roads, side roads
etc, or simply make the reptiles more vulnerable to incidental mortality.
9.3.2
COLLATERAL HABITAT CREATION
As the features identified in 9.2.5, ‘Collateral habitat creation’ mature, so their suitability for
reptiles would be expected to increase, at least in the medium-term. Subsequent management
would be required to maintain a high degree of habitat ‘structure’.
9.3.3
SOFT ESTATE MANAGEMENT REGIMES
Whilst, as identified above, some habitat management is likely to benefit reptiles, mowing and
strimming in particular can be important hazards for individual reptiles inhabiting the soft
estate, both as a direct threat of injury or mortality from machinery and indirectly though a
sudden reduction in cover from predators.
9.3.4
MAINTENANCE OF HARD LANDSCAPING/STREET FURNITURE
Operations such as the clearance or replacement of ‘french drains’ and similar systems, works
on particular structures, the maintenance of retaining features and a variety of other activities,
can have implications for reptiles using these structures as refuges or hibernacula.
9.3.5
PUBLIC ACCESS TO ROAD VERGES
The potential impacts identified in 9.2.6 are also relevant to the existing road network.
MAY 2005
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CHAPTER 10
10.1
INTRODUCTION
Measures proposed to mitigate the effects of road schemes on reptiles should be
proportionate to the importance of the reptile population(s) that would be affected, and the
scale of the potential impacts upon them. However, it is also appropriate to take advantage of
opportunities presented by new schemes or options for management of existing verges, to
achieve targets set out in the overseeing organisations’ BAPs for the enhancement of reptile
habitat and populations.
It is obviously not feasible to discuss all possible options for mitigation here. The principles are
discussed below, but the design of all substantial mitigation schemes, and any involving sand
lizard and smooth snakes, should be developed in consultation with the relevant SNCO.
10.2
NEW SCHEMES
10.2.1 AVOIDING KEY FEATURES AND SENSITIVE/VALUABLE HABITATS
Wherever possible, sensitive route choice, small-scale variations in alignment and minimising
the extent of land-take should be used to ensure that key habitats and features, identified
during the Environmental Assessment process, are avoided. Where this is not possible, the
extent of any habitat loss should be minimised. In almost every case, it is preferable to attempt
to retain reptile populations in situ. Where habitats are retained within or adjacent to the
construction site, temporary protective fencing should be installed to help reduce the chances
of incidental damage.
As well as avoiding direct impacts, indirect effects such as adverse hydrological changes
should also be minimised through sensitive drainage design and good engineering practice.
Other potential effects can also be minimised through design; for example the location of new
lay-bys away from valuable features, and the use of fire breaks, to minimise the likelihood of
future damage to adjoining habitats.
10.2.2 MINIMISING FRAGMENTATION
By reference to the information collected at Assessment Stages 1, 2 and 3 with regard to how
reptile populations appear to be distributed in the vicinity of the new scheme, consideration
should be given throughout the process of route choice and scheme design, to selecting a
final route which would cause the least fragmentation.
Where fragmentation of some kind is unavoidable, consideration should be given to the use of
safe road crossings to minimise the subsequent effects of isolation and increased road
mortality. There is some evidence that certain reptile species will use road/farm underpasses
to cross roads and ‘green bridge solutions’ are intuitively likely to be effective, to some degree.
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MITIGATION MEASURES
There is, however, a general lack of conclusive information about the use of these kinds of
structures by reptiles, particularly purpose-built tunnels (both those designed for amphibians
and reptiles, and larger structures such as badger or otter tunnels).
10.2.3 HABITAT CREATION AND ENHANCEMENT
Where suitable reptile habitats would be lost unavoidably as a result of road construction,
mitigation in the form of habitat creation and enhancement is appropriate, with the aim of
achieving no net loss of valuable reptile habitats. Habitat creation as an integral part of reptile
relocation/translocation operations is dealt with in more detail below, but there are also a
range of opportunities as part of routine road and landscape design. These include:
l maximising the extent of south-facing slopes, particularly where these can be juxtaposed
with other habitats and features of value;
l incorporating as much small-scale variation in topography and exposed substrates as is
feasible;
l designing a landscape scheme that will develop a ‘mosaic’ of different vegetation types
and that will provide ‘links’ between features of value;
l promoting the use of open, sustainable drainage structures, and pollution control and
attenuation measures (both to provide valuable habitats and to reduce levels of incidental
mortality); and
l looking for opportunities to incorporate no-cost/low-cost features that will act as
hibernacula, refuges, basking sites, egg-laying sites, etc.
10.2.4 AVOIDING INCIDENTAL MORTALITY DURING CONSTRUCTION
10.2.4.1 Seasonal constraints and programming
Wherever possible the significant seasonal variations in behaviours exhibited by reptiles
should be taken account of, within the work programme, in order to schedule particular
operations to avoid periods where reptiles are most at risk. It is sometimes possible, for
example, to clear those areas of habitat that it would clearly not be possible for hibernating
reptiles to use (heavily waterlogged areas, for example) during the winter, when reptiles are
seasonally absent.
10.2.4.2 Temporary reptile-proof fencing
Where working areas adjoin valuable reptile habitats, it is often appropriate to install reptileproof fencing to discourage animals from wandering onto the site and potentially being killed.
Although construction-related disturbance is likely to deter many reptiles from moving onto the
working areas, construction sites often contain stockpiled materials and other structures which
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MITIGATION MEASURES
can be attractive to reptiles, particularly during a period of inactivity within the site. Given the
expense of installation and maintenance, it is appropriate to undertake a brief risk assessment
before deciding whether or not temporary reptile-proof fencing is necessary. The factors to
consider include: the presence of reptiles in adjacent habitats; the connectivity of these
habitats to the working area; the continuing suitability of habitats for reptiles within the working
area; the duration of works; and whether there are any existing barriers that can be utilised or
made reptile-proof. In addition, an assessment of capture (or recapture) results, can help to
indicate where fencing is required in the context of a translocation/relocation operation (see
below).
During the life of the works it will be necessary to monitor and maintain the fence regularly to
ensure its integrity. Permanent reptile-proof fencing is rarely appropriate, unless needed to
‘funnel’ animals towards a safe crossing point, since the developing verge habitats are likely to
represent a valuable resource that it would be counter-productive to exclude them from, in the
interests of reducing reptile road mortality. Detailed reptile fencing specifications are shown in
Annex B.
extend to September. Reptiles should not be translocated later than mid- to late-September
depending upon weather and latitudes.
(ii)
The specifications for appropriate receptor sites depend largely upon the numbers of animals
that would be released into them and the species involved. It is obviously difficult to give
generic advice, but the following principles should be considered:
a)
Location
Receptor sites should ideally be close to ‘donor’ sites, with good ‘links’ to surrounding
habitat suitable for reptiles and should not be isolated from other existing reptile
populations.
b)
Habitat
The receptor site should comprise similar habitat types and features to those at the
donor site; particularly those identified as being of importance to the reptiles to be
moved. Each site should include all of the features necessary to support all aspects of
the reptiles’ life-cycle and reflect the ecology of the species concerned.
c)
Size
Ideally, a receptor site should be at least equal in size to the donor site in question
(although not necessarily the same configuration) and ideally greater in size, unless it
is clear that substantially more productive habitat can be created. In most cases it is
sensible simply to assume that the donor reptile populations are at ‘carrying capacity’
for the habitats within the donor site, and make provision for them at the receptor site
by creating at least an equivalent area and an equivalent proportion of habitat types.
Population estimates will generally not be required for the more common species..
However, when dealing with sand lizards or smooth snakes, the pre-translocation
investigations will have been more comprehensive, and the suitability and productivity
of the receptor site will need to be more critically evaluated. Generally a greater (more
precautionary) provision will be appropriate.
d)
Pre-existing populations
For substantial translocation projects, receptor sites should generally not support the
species to be moved (but they should be suitable for them). This assumes that a
suitable founder population may be translocated (see (e) ‘Founder population
structure’, below).
10.2.4.3 Translocation/relocation
For the purposes of this Advice Note, ‘translocation’ refers to the capture and release of
reptiles some distance from their original location, whereas ‘relocation’ is used to indicate
short-distance movements to within the same area of habitat. In each case, translocation or
relocation should represent a last resort, where avoidance is not possible.
Where it is not possible to avoid areas which are used by at least some reptiles throughout the
year (and thus there is no ‘safe’ period during which works may proceed), some form of
capture and removal operation is required as a last resort to avoid killing or injuring reptiles
during site clearance. The key issues and constraints associated with these operations are
described below. The surveys and other investigations which may be required to underpin
these operations are described above in Section 6.3, ‘Surveys for new road schemes’.
(i)
Programming issues
Advance consideration of programming issues is one of the keys to a successful translocation
operation. It is particularly important to incorporate sufficient time for advance works at the
receptor site (see below), in order for it to be ready to receive the donor site animals, and
sufficient time for the anticipated full extent of the capture operation. It is also important to
remember that the capture operations will be seasonally constrained; not only can animals
only be captured effectively between April and September, but the capture operation should
always include a spring/early-summer period (April to June) when captures are at their most
efficient. Capture rates during mid-summer may be poor due to hot summer weather; hence if
a substantial number of animals remain to be captured in mid-June, the operation may need to
MAY 2005
‘Receptor’ site selection and advance works
Where only small numbers of reptiles are being translocated, it is essential that a
pre-existing population is present at the receptor site in order to maintain a viable
population, and that appropriate habitat enhancement is undertaken to boost its
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carrying capacity, or that adjoining habitat features are created. Improving previously
unsuitable habitat adjacent to sites that support existing populations is often the most
appropriate option.
e)
Founder population structure
If relocating animals to an area with few or no reptiles, and to one which is not
immediately adjacent to sites which support existing populations, it is important that the
nucleus of a viable population is relocated (particularly if ‘splitting’ animals between
receptor sites). It is difficult to provide definitive guidance, since each of the key
parameters will vary in detail between sites and species. Some studies have suggested
that establishing ‘new’ populations is also best accomplished with releases over
successive seasons. This is often difficult to achieve in the context of a road
development project. Thus moving animals to a location adjacent to existing
populations is often a more appropriate solution.
The details of all translocation projects involving smooth snakes or sand lizards should
be developed in consultation with the relevant SNCO and this should include issues of
founder population size and structure. Recommendations with regard to minimum
numbers for these species are therefore not presented. In addition, research continues
to be undertaken on minimum viable founder population sizes for different reptile
species. Thus, where uncertainty exists, further guidance should be sought from the
relevant SNCO and the relevant highways authority Environmental Advisor.
f)
Advance habitat creation/enhancement
It will usually be necessary to undertake works in order to prepare the receptor site.
These must be done sufficiently in advance of translocation to ensure the availability of
prey, cover, etc., for the released animals. Where translocations are carried out late in
the season, the availability of suitable hibernacula is critical and animals should be
released in close proximity to them. The habitat creation and enhancement works will
be site-specific, but are likely to involve similar measures to those set out in Section
10.2.3, ‘Habitat Creation and Enhancement’ (above), along with the specific installation
of purpose-built hibernacula. Selected designs for structures are presented in Annex D.
For operations involving sand lizards and smooth snakes, it may also be necessary to
monitor the condition of the receptor site pre-release (for example, by surveys of prey
species) and to incorporate ‘soft-release’ techniques.
g)
Measures to prevent return to the donor site
It will generally be appropriate to incorporate an effective barrier (usually in the form of
temporary and, possibly more permanent, reptile-proof fencing) to prevent the return to
the donor site of translocated individuals.
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MITIGATION MEASURES
h)
Long-term management
In most cases receptor sites will require some form of longer-term management, in
order to maintain favourable conditions for the newly-established or expanded
populations. The details of such management would need to be determined on a caseby-case basis.
i)
Multiple receptors
In some cases, value can be added by creating multiple receptor sites. Sites should be
linked by suitable habitat features to provide connectivity between the new subpopulations, thus allowing movement of individuals and maintaining the viability of the
population as a whole. This approach would be expected to have an increased chance
of success since it avoids the possibility of unforeseen events affecting a single
receptor.
(iii)
Capture methods
Reptiles are generally captured in similar ways to when surveying. Again, pitfall traps tend not
to be used on welfare grounds and ‘nooses’, which are sometimes useful in capturing lizards
(particularly sand lizards), should only be used by skilled practitioners. An important element
of any operation will be its ‘active management’. It is inappropriate simply to set out a grid of
artificial refuges at the beginning of the season and to continue to collect reptiles from them
without reviewing the situation. Instead, it is very important that refuge locations and densities
be manipulated throughout the operation, along with the use of fencing, vegetation and
destructive searches as described below, all with the aim of maximising capture efficiency and
the ability to capture each of relevant species and life stages.
a)
Artificial refuge densities
These will generally be up to ten times greater than those used in survey situations (or
even more at particular ‘problem’ sites where, for example, there are abundant natural
refuges or unusually diverse populations). Even more so than for targeted surveys at
Stage 3, it is helpful to use different artificial refuge types and sizes to maximise the
range and efficiency of captures, and to undertake more frequent visits and at different
times of day.
b)
Temporary fencing
It is often helpful to divide up donor sites with ‘drift’ fencing, to increase capture
efficiency, as well as using a perimeter fence to prevent re-colonisation. However, this
should be installed in such a way as to minimise the possibilities of injuring or killing
reptiles. In many cases the use of a perimeter fence around at least part of the
exclusion area will be essential to complete a removal operation, by limiting the
continual spread of animals onto the exclusion area from adjacent habitats and/or
immigration from donor sites. Similarly, lengths of fencing can be used to segregate
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MITIGATION MEASURES
It is certainly necessary to review the capture results of any project critically, to
determine whether numbers are declining significantly or whether this is an artefact.
For example, if a period of better weather or a change in capture methods results in a
substantial increase in numbers captured, there is a clear need to continue the capture
operation and to increase capture effort.
those parts of the site already clear of reptiles, from areas where reptiles remain to be
captured (particularly prior to the production of juveniles, which might otherwise readily
colonise cleared areas).
c)
Vegetation removal
As a capture operation progresses it is often helpful to undertake carefully supervised
vegetation cutting/removal to limit available refuges sequentially and thus increase
capture efficiency, particularly toward the end of a capture operation; it is often best to
begin captures in undisturbed vegetation, which tends to promote higher initial capture
rates.
e)
In addition, in those situations where animals are being moved from only part of a site
and at least one of the aims of the operation is to relocate individuals to the retained
areas, it is often helpful to use the sequential cutting-back of vegetation followed by the
erection of one-way reptile-proof fencing, to help displace animals from the working
area, as an adjunct to a capture and relocation operation. Clearly any such vegetation
removal would also need to take account of other constraints, including the possible
presence of nesting birds.
d)
Timescale
It is very difficult to give generic advice as to how long translocation operations will
take. The Herpetofauna Groups of Britain and Ireland have published guidance
indicating what constitutes ‘reasonable effort’ where capture operations are concerned
(see ‘Further Reading’). They state that captures should extend over a period of
between three months and an entire season of intensive effort, depending upon
population density, although some of the measures detailed above may be effective in
achieving reductions to these periods. To be effective the operation will almost always
need to encompass at least one spring and early summer period (April to June
inclusive) when captures are most efficient. In extreme cases, involving particularly
large and ‘difficult’ sites, with high reptile densities, captures may have to extend over
part (or possibly all) of two seasons.
A reasonably sound approach is to monitor declining capture rates. However, declining
captures through June and September may simply be a reflection of declining capture
efficiency, rather than a dwindling donor population. It is also often difficult to fit removal
trapping ‘models’ to these data to extrapolate a final population size, since the
associations involved in capturing reptiles in this way are very unlikely to be linear, will
be significantly skewed by variations in climate and related issues, and capture effort
will also rarely be constant. Nevertheless, recent research has suggested that if dealing
with relatively small, largely ‘closed’ populations (i.e., where immigration and/or
recruitment are unlikely during the period) and where an intensive capture operation is
possible, these models might be helpful.
MAY 2005
Timing
Wherever possible, capture operations should begin early in the year, both to take
advantage of the most productive period, and to catch female reptiles before they have
had a chance to lay eggs/give birth. Wherever possible capture operations should not
be designed so that there is a period during which animals have to be kept in captivity
or a temporary holding area. Nor should animals be released into a new area just prior
to the hibernation period as this could affect their future survival.
However, September can be an effective part of the year during which to capture
reptiles. Releases at this time of year therefore need to take account of the potential
effects on the animals concerned. Late-season releases can have the most significant
implications for the more behaviourally complex species (snakes in particular).
Nevertheless if reliably frost-free hibernation sites, free from obvious predation risks
are readily available and there are no welfare contra-indications (i.e. the individual
concerned is in good condition and, in the case of lizards, has not recently shed its
tail), then moving animals (lizards in particular) up to mid-September at least should be
considered.
f)
Destructive searches
Once a ‘reasonable capture effort’ has been expended, ideally once capture rates have
declined towards zero, (so long as a sufficient capture effort has been maintained and
this is not a seasonal artefact), a final ‘destructive search’ should be undertaken just
before and then in parallel with the first elements of site clearance. This needs to
involve the careful supervision of plant or work by hand. The intention of the destructive
search should be to dismantle structures and/or excavate substrates in such a way that
any reptiles present will be revealed and, if possible, there will be an opportunity to
rescue the animals in question unharmed. It tends to be a slow process and, given
their cryptic nature, even with the most careful operation, injuries and mortalities will
undoubtedly occur if a substantial number of reptiles remain.
At the very least a destructive search should be sufficient to identify a situation where
the previous capture operation has not been fully effective, so that remedial capture
works can take place. However, in relatively easily-searched situations, a destructive
search can also be helpful in capturing and removing the last few individual reptiles
without compromising their welfare. Generally the best approach to adopt is to begin
the search in a very careful, exhaustive, and precautionary manner, and gradually
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increase the speed of the operation assuming that reptiles continue not to be found.
Destructive searches should only be carried out during those periods when reptiles are
active.
It is very rarely acceptable to undertake site clearance without a prior capture
operation. This may be appropriate only when captures are impossible for some
reason, or a very small impact coupled with a low likelihood of reptiles being present
can be demonstrated. It would be difficult to prove that ‘reasonable effort’ had been
used in such situations, and in all cases, a destructive search carried out by an
ecologist would be essential.
10.2.5 AVOIDING INCIDENTAL MORTALITY ASSOCIATED WITH DRAINAGE
STRUCTURES
Although this appears to be less important for most reptile species than it can be for
amphibians, it is nevertheless important to avoid, wherever possible, the use of kerbs and
road drains, gully pots, traditional petrol/oil interceptors, and other sheer-sided chambers and
similar structures. These could potentially trap reptiles, and should be avoided in situations
where reptiles (particularly the least common species) are likely to use habitats close to the
roadside, or attempt to cross the road regularly. In these situations, more sensitive solutions
should be considered; many have already been developed specifically for amphibians and as
parts of vegetative treatment systems (see DMRB Vol. 4, Section 2, Part 1, ‘Vegetative
Treatment Systems for Highway Runoff’).
10.3
THE EXISTING ROAD NETWORK
10.3.1 AVOIDING KEY FEATURES AND SENSITIVE/VALUABLE HABITATS
Clearly, when dealing with works to existing road verges, there are fewer opportunities to avoid
sensitive or valuable habitats. If key features (for example hibernacula) are sufficiently
restricted in their number or extent; then it may be possible to avoid them, but works within the
existing verge are often strictly constrained to a particular location or alignment. Thus, whilst it
is appropriate to attempt to adopt the principles of avoidance and minimising impacts, in
practice this may not be achievable.
However, if routine habitat management works would, or have had, an adverse effect on a key
feature, then it would be important to incorporate a special instruction within the landscape
maintenance specification for this location, so that the particular habitat feature can be
protected and managed appropriately in the future. In addition, if a particular area is identified
as vulnerable, then measures could be put in place to protect it (for example as described for
new schemes, fire breaks can be established beside existing roads to protect adjacent
habitats).
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10.3.2 MINIMISING FRAGMENTATION
Works to existing verges would rarely be expected to have a long-term impact of increasing
fragmentation. However, if habitats outside the soft estate are sub-optimal for reptiles, some
works could cause the temporary isolation of lengths of suitable habitat. Habitat management
operations (for example mowing), which take in the entire width of the verge, could have
similar short-term effects. In these circumstances, it would be appropriate to retain ‘links’ of
suitable habitat to help offset any fragmentation effects.
10.3.3 HABITAT CREATION AND ENHANCEMENT
Habitat creation and enhancement in the context of relocation schemes is discussed below,
but there are also a range of opportunities, as part of routine landscape/habitat management
works, to improve the soft estate for reptiles. These include minor alterations to the landscape
maintenance specifications to produce more of a ‘mosaic’ structure within the roadside
habitats, avoiding large areas of grass of a uniform height. In addition, introducing selective
coppice management and thinning at an earlier stage than usual, to maintain open features (of
a variety of aspects) within developing shrub and tree planting areas can be helpful.
Maintenance works could also include specifications to compost arisings in locations where
they are most likely to be used as egg-laying sites, and to retain brash piles adjacent to linear
features, and scattered cut timber as refuges and hibernacula (also see Annex D ‘Hibernacula
Design’, and Annex F ‘Photographic Examples of Principal Issues’ for examples). By not
removing the stumps of felled trees, features which may be used as hibernacula may remain
unaffected, and the opportunities for potential hibernacula to form may be increased as they
rot in situ.
As information becomes available on the distribution of reptiles across the network,
particularly detailed information about the occurrence of different populations and key habitat
features, these measures could (a) be targeted to produce the most beneficial effects, and (b)
these new potentially valuable habitat features could be located in positions least likely to
present subsequent problems with regard to other maintenance activities.
10.3.4 AVOIDING INCIDENTAL INJURY AND MORTALITY
10.3.4.1 Seasonal constraints and programming
As for new schemes, maintenance and management works should take account of the
reptiles’ seasonal patterns of activity and behaviour and, wherever possible, avoid periods
where reptiles are most at risk. For example, mowing, strimming or other habitat maintenance
around features used as communal hibernacula could harm large numbers of reptiles as they
bask both before and, in particular, after the hibernation period, and so should be avoided at
these times.
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10.3.4.2 Specification of maintenance works
(ii)
Several routine maintenance operations constitute potential sources of injury and mortality for
reptiles, particularly mowing and strimming for road safety and amenity reasons.
Consideration should therefore be given to raising the height to which grass is cut to a
minimum of 150 mm. This should certainly be specified for areas where reptiles are known to
be common or to aggregate, and where smooth snakes and sand lizards are known to occur
on the verge. However, given the widespread nature of some of the more vulnerable reptile
species across the network, consideration should be given to adopting this specification for
most works; unless there is a particular need to reduce cutting heights or increase cutting
frequencies to for other reasons. The use of ‘litter hoovers’, which create substantial updraft,
should be avoided on areas where reptiles may be present. Similarly, snakes routinely take
refuge at the base of young trees and shrubs, so strimming should be avoided in very close
proximity to these.
Again, the principles are the same as for new schemes, but it will generally be less feasible to
consider off-site translocation, and the operation far more frequently involves ‘relocation’ to
adjacent areas of road verge, rather than ‘translocation’. In addition, the donor site is often not
completely lost, for example if it is simply subject to a trenching operation or similar, and the
receptor site only has to act as such on a temporary basis. It is still important to consider
advance measures to increase its carrying capacity or include additional areas to promote the
survival of the relocated animals, but the issues are less critical. It will almost always be
necessary to install measures to prevent premature re-colonisation of the donor site.
Where reptiles are known to aggregate in substantial numbers, and bask in areas where they
are particularly vulnerable, consideration should also be given to including a specification not
to cut these areas until towards the middle of the day and on warm or sunny days wherever
possible, to give the animals the best chance of escaping safely. Indeed, as the landscape
contractors become familiar with where particular aggregations of reptiles occur, it may be
possible to ‘beat’ the vegetation (in selected areas only) just prior to cutting (literally within a
few minutes) to further help avoid incidental mortality. It will also be appropriate in these areas
to review the use of heavy ground-pressure or wide-tracked vehicles or in detail how these are
used in order to minimise the likelihood that animals are crushed as part of routine
maintenance works.
(iii)
Receptor site selection and advance works
Capture methods
Each of the issues set out for new schemes also apply to existing roads. Capture operations
tend to be completed more quickly, since they usually involve smaller, more constrained areas
and it is often appropriate to include an element of vegetation removal in order to displace
animals, to augment attempts to actively capture and relocated them. Whilst the principle
remains that planning to keep animals in temporary holding facilities or captivity is
inappropriate, ‘last-minute’ rescue operations can result in insoluble seasonal, welfare and/or
logistic constraints. Keeping animals in captivity (for example over winter) or in temporary
receptor areas is generally not recommended because of the extra stress it can place on the
animals, the increased likelihood of disease (and heightened disease risk if kept close to nonnative species), the difficulties in establishing and maintaining effective hibernating conditions
and the extreme difficulties caused by subsequent delays. Wherever possible, the situations
which conspire to make this necessary should be avoided by informed planning of future
works.
10.3.4.3 Translocation/relocation
The majority of the principles and details discussed for new schemes are also relevant to
undertaking these works on the existing road network. However, there are some additional
constraints and differences in emphasis. These are discussed below, following the same
numbering sequence:
(i)
Programming issues
Advance consideration of programming issues are just as crucial when dealing with works to
existing road verges. Theoretically advance works are less constrained, since there are no
delays associated with Public Inquiry, CPO, etc. However, these smaller-scale works often
have much shorter lead-in times and may be more strictly constrained by season or a final
deadline.
MAY 2005
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CHAPTER 11
11.1
CONTRACT IMPLEMENTATION
VOLUME 10 SECTION 4
PART 7 HA 116/05
PLANNING AND ADVANCE WORKS
Chapter 7 sets out the requirements for updating reptile surveys pre-construction. Surveys and
supervision associated with site clearance will also serve to validate these findings and where
any significant changes are identified, this should be used to inform a review of mitigation
design.
Many of the mitigation measures described in Chapter 10 require to be undertaken as
advance works, conceivably up to two years pre-construction, but more usually during the
preceding season. Clearly, the necessary temporary fencing to exclude reptiles should be in
place before construction works begin.
11.2
CONSTRUCTION-PHASE SUPERVISION
Mitigation measures should be designed by appropriately experienced ecologists and,
crucially, be installed under expert ecological supervision, if necessary using specialist
contractors. A suitably experienced Ecological Clerk of Works would also be required
subsequently, to monitor various aspects of the ongoing works, including the status of any
receptor sites, and to ensure that construction operations neither damage nor interfere with
any remaining reptile mitigation measures.
MAY 2005
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CHAPTER 12
12.1
‘SURVEILLANCE’ MONITORING
Surveys of reptile populations should be carried out in areas of suitable habitat within the soft
estate, to improve the knowledge of the distribution of reptiles - an objective of the HABAP and
TREBAP species action plans (SAPs) for reptiles. This information could be collected by the
Area Teams, or equivalents, with the standard protocols for reptile surveys of existing road
schemes employed (see Section 6.3), and the data analysed centrally. This would provide
national overviews of reptile populations within the soft estate. Furthermore, if simple habitat
information could be collected at the same time, the resulting data would be even more
valuable and would facilitate a predictive approach to subsequent decision making with regard
to mitigation.
12.2
VOLUME 10 SECTION 4
PART 7 HA 116/05
MONITORING
POST-CONSTRUCTION MONITORING
Post-construction monitoring should be carried out to assess the success of mitigation
schemes for both new and existing road schemes. Given that, for many schemes, where only
small numbers of common reptile species are likely to be affected, it is considered
unnecessary to carry out detailed population monitoring pre-construction, detailed postconstruction monitoring of all schemes would not prove cost-effective. A sample of mitigation
schemes should therefore be monitored to provide data on a variety of mitigation methods, for
a range of different reptile species, in different regions, and the selection of these should be
co-ordinated nationally. This is likely to include all schemes which affect sand lizards and
smooth snakes, as it would form part of the licensing conditions, and should also include all
schemes affecting large reptile populations. It would also be appropriate to include a number
of smaller schemes, which affect only small numbers of common reptile species, to allow
comparisons to be drawn.
The methods used for post-construction monitoring would be dependent upon the original
mitigation measures, as described below:
upon the species involved, as well as the scale of the impact. The timescale for each
individual scheme should be determined on a scheme-by-scheme basis, in consultation with
the relevant SNCO. For licensed operations, these are likely to be between 5 and 10 years in
duration. For more routine operations involving common species, consideration should be
given to monitoring during the establishment phase, in part to help deliver commitments in
BAPs.
12.2.2 HABITAT ENHANCEMENT
Habitat enhancement works can include the creation of artificial structures, such as
hibernacula or egg-laying sites, and habitat manipulation works, for example improving habitat
structure and ‘mosaic’ planting. Monitoring should include an assessment of the success of
such measures. The use of artificial hibernacula, for example, can be assessed through
surveys for basking individuals early in the season, when reptiles will bask close to their
hibernation sites.
An assessment of the success of habitat manipulation would require a combination of
population surveys, as described for post-construction monitoring above, and some form of
habitat monitoring, such as fixed-point photography. In addition, monitoring of habitat structure
would also be appropriate, particularly if this can be linked to remedial management.
12.3 MONITORING THE SUCCESS OF MITIGATION CARRIED OUT FOR
MAINTENANCE WORKS
Monitoring of the success of mitigation measures carried out for maintenance projects should
also be carried out. This should also focus on a sample of different mitigation schemes to be
determined nationally, with similar methodologies and timescales to those described for postconstruction monitoring above. The sample should aim to include all projects affecting sand
lizards and smooth snakes, and a range of different schemes affecting the more common
species.
12.2.1 RELOCATION SCHEMES
Post construction monitoring of relocation schemes should assess a combination of
population size and density, and individual survivorship. This should be done as described for
new and existing road schemes in Chapter 6, ‘Reptile Survey Methods. As highlighted in
Section 6.3.3.3, the repeated handling of reptiles and more intrusive techniques should only
be undertaken where there would be substantial benefits in doing so. A proportion of
monitoring projects should focus on a similar range of aims as those defined for routine
surveys in Section 6.3.3.1. However, some should also involve longer-term population studies,
and would include the photographing of characteristic patterns to allow the recognition of
recaptured individuals. Given that there is considerable variation in the longevity of the
different reptile species, the time-frame for monitoring would be, to some extent, dependent
MAY 2005
12/1
Chapter 13
Enquiries
Volume 10 Section 4
Part 7 HA 116/05
13. ENQUIRIES
All technical enquiries or comments on this Advice Note should be sent in writing as appropriate to:
Acting Divisional Director
1A PED Federated House
London Road
Dorking
RH4 1SZ
GERRY HAYTER
Acting Divisional Director
Chief Road Engineer
Scottish Executive
Victoria Quay
Edinburgh
EH6 6QQ
J HOWISON
Chief Road Engineer
Chief Highway Engineer
Transport Wales
Welsh Assembly Government
Cathays Parks
Cardiff
CF10 3NQ
M J A PARKER
Chief Highway Engineer
Transport Wales
Assistant Director of Engineering
The Department for Regional Development
Roads Service
Clarence Court
10-18 Adelaide Street
Belfast BT2 8GB
D O’HAGAN
Assistant Director of Engineering
May 2005
13/1
LIST OF ANNEXES
ANNEX A
Review of Legislation and Guidance
ANNEX B
Design of Reptile-Proof Fencing
ANNEX C
Artificial Refuge Specification
ANNEX D
Hibernacula Design
ANNEX E
Desk Study Consultees
ANNEX F
Photographic Examples of Principal Issues
ANNEX G
Decision Matrix
ANNEX H
Acknowledgements
ANNEX I
Further Reading
ANNEX J
Glossary
MAY 2005
VOLUME 10 SECTION 4
PART 7 HA 116/05
ANNEX A
REVIEW OF LEGISLATION AND GUIDANCE
A1
The legislation relating to the protection of reptiles in Britain is contained mainly
within the Wildlife and Countryside Act (1981), as amended by the Countryside and Rights
of Way Act (2000), and the Habitats and Species Directive (92/43/EC), enacted in the UK
through the Conservation (Natural Habitats, &c.) Regulations (1994). (In Scotland the
Nature Conservation (Scotland) Act (2004) applies relative to Sites of Special Scientific
Interest - SSSI.) All legislation relevant to the conservation of reptiles in the context of the
design and management of highways is summarised below. (Please note that this is not a
complete resume of all of the provisions of the legislation, but only as it may relate to
highways works. Thus, for example, regulations regarding sale and exchange of reptiles
have been omitted.)
Wildlife and Countryside Act (1981) and amendments; and the Countryside
and Rights of Way Act (2000); for those parts of the UK to which this Act
applies)
A2
All six native reptile species receive protection under Section 9 of the Wildlife and
Countryside Act 1981. However, the four more common reptile species (common lizard,
slow-worm, adder and grass snake) only receive protection in respect of part of Section 9(1)
and all of Section 9(5). All elements of Section 9 of the Wildlife and Countryside Act 1981
apply to sand lizard and smooth snake. There are, therefore, two levels of protection under
the Wildlife and Countryside Act (1981) relating to reptiles.
A3
Under the provisions of Section 9 it is an offence to intentionally kill or injure any of
the six native reptile species. It is also an offence to intentionally take a sand lizard or
smooth snake; intentionally or recklessly damage, destroy, or obstruct access to, any
structure or place a sand lizard or smooth snake uses for shelter or protection; or disturb a
sand lizard or smooth snake while it occupies such a structure or place.
A4
Activities which could result in the death or injury of the more common species are
not licensable and rely on the defence that any such outcome is the incidental result of a
lawful operation, and could not reasonably have been avoided. In order to demonstrate that
reasonable steps have been taken to avoid the death or injury of reptiles, it is necessary
that the best practice guidance contained in this document be implemented as appropriate.
In addition, it is also recommended that the appropriate SNCO be consulted and allowed a
reasonable period in which to provide advice should they consider it necessary.
A5
Licences can be granted by the appropriate SNCO for otherwise unlawful activities
affecting smooth snakes and sand lizards, associated with conservation, science and
education. These include the various survey techniques that might need to be used in
association with highways projects. Further details with regard to licences available for
development activities that would affect sand lizards and smooth snakes are presented in
Section A8 (below).
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VOLUME 10 SECTION 4
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The Habitats and Species Directive 92/43/EEC/ Conservation (Natural Habitats,
&c.) Regulations (1994)
A6
The Council Directive 92/43/EEC of 21st May 1992 on the Conservation of Natural
Habitats and of Wild Flora and Fauna exists to promote the maintenance of biodiversity in
Europe. The Annexes of this Directive list habitats and species of importance in a Europe-wide
context and, of the six native UK reptile species, only smooth snake and sand lizard are
included.
A7
Under regulation 39 of The Conservation (Natural Habitats, &c.) Regulations (1994) it is
an offence to deliberately capture or kill a smooth snake or sand lizard; deliberately disturb a
smooth snake or a sand lizard; deliberately take or destroy the eggs of a sand lizard; or to
damage or destroy a breeding site or resting place of a sand lizard or smooth snake.
A8
Licences can be granted for developments which preserve public health or safety, or
for other imperative reasons of overriding public interest including those of a social or
economic nature and beneficial consequences of primary importance for the environment.
This would be the basis on which road development schemes which may affect sand lizards or
smooth snakes could proceed. However, licences will only be granted where there is no
satisfactory alternative, and where the development will not be detrimental to the maintenance
of the population of the species concerned at a favourable conservation status in their natural
range.
The Bern Convention
A9
The convention on the Conservation of European Wildlife and Natural Habitats came
into force in 1982 and was the first international convention covering all aspects of protection
of the natural heritage. Sand lizard and smooth snake are listed on Appendix II of the
Convention and afforded special protection. The protection afforded to these species is
already enshrined in the Wildlife and Countryside Act 1981 (see above).
Planning Policy Guidance No 9 (in England)
A10 PPG 9 has implications for local authority road schemes and ancillary development
such as MSAs/MMAs which are governed by the Town and Country Planning Act (1990). PPG
9 embodies the Government’s commitment to conserving biodiversity and states that “the
presence of a protected (under the Wildlife and Countryside Act 1981) species is a material
consideration in considering a development proposal”. Although the concept of ‘material
consideration’ does not apply to highway schemes, Planning Policy Guidance can be seen as
providing good practice guidance. A revision of this guidance will be presented in PPS9
(Planning Policy Statement 9).
A/1
ANNEX A
REVIEW OF LEGISLATION AND GUIDANCE
VOLUME 10 SECTION 4
PART 7 HA 116/05
Biodiversity: The UK Action Plan
A11 The Convention on Biological Diversity was signed by the UK following the
1992 Earth Summit in Rio de Janeiro. In 1994, the Government produced the UK
Action Plan, a national strategy for the conservation of biodiversity. Individual
‘Species Action Plans’ have been drawn up for many of the most-threatened
species. Of the six native reptile species, the Government has identified one, the
sand lizard, as a ‘priority species’, for which an Action Plan has been prepared;
and four, the slow-worm, the smooth snake, the grass snake and the adder, as
‘species of conservation concern’. Any highway schemes potentially affecting
sand lizards should ensure that mitigation proposed is compatible with the
existing Action Plan.
MAY 2005
A/2
ANNEX B
DESIGN OF REPTILE-PROOF FENCING
VOLUME 10 SECTION 4
PART 7 HA 116/05
Temporary Reptile Fence
250 ì thick, UV-stable polythene
membrane. (Minimum roll width: 1000
mm.)
This is a standard temporary fence design which can be utilised in situations where it is
necessary to create a reptile-proof barrier for periods usually not exceeding a single season.
Although this design will effectively prevent the passage of reptiles in either direction, the
‘returns’ on the fence should face outwards, i.e. facing the direction from which the majority of
any reptiles are expected to approach. It can be constructed from relatively inexpensive
materials, but is easily damaged or vandalised, and will degrade over time. Fences of this type
are less appropriate in windy situations where damage will be more frequent. Also if placed
close to areas where plant operate regularly and/or earthworks are taking place, a membrane
fence of this kind is usually best protected by a more robust fence, for example a wooden
paling fence.
Care needs to be taken when undertaking the necessary maintenance works to ensure that
vegetation does not grow over the fence. If undertaken mechanically, this can easily damage
the membrane.
Polythene folded over and stapled to
19x38x100 mm rough sawn (RS)
softwood batten to form an overhang.
19x38x100 mm RS softwood batten;
this acts as a spacer to create effective
overhang.
19x38x500 mm RS softwood batten;
attached to the post using 50 mm nails,
sandwiching the membrane.
600 mm
50x50x1200 mm RS softwood post.
Spacing at 1.5 m intervals.
Backfill compacted as far as possible to
ensure that no fissures or gaps are left
in the backfill or against the polythene.
The use of a nail gun is recommended to attach the battens securely to the posts. Not only is
this advantageous for speed, but prevents any loosening of the posts which can be associated
with the repeated impacts of a hammer.
Some practitioners prefer the use of flexible plastic washers to hold the membrane in place, as
an alternative to softwood battens. (An example of this is shown inset.) The result is similar in
strength and durability to that of the previous design, but precludes the use of a nail gun, as
the washers require a large headed nail and cannot withstand the force produced by the gun.
Polythene turned out to form a buried
'return'.
This 'return' should face
outwards from the excluded area, i.e.
facing the majority of amphibians
seeking to cross it.
150 mm
300 mm
100 mm
32 mm diameter plastic washers can
be used to affix the polythene
membrane to the posts (with 40 mm,
broad-headed nails).
A small off-cut from a post allows the
creation of an effective return at the top
of the polythene membrane.
MAY 2005
B/1
ANNEX B
DESIGN OF REPTILE-PROOF FENCING
Temporary One-way Reptile Fence
This design can be utilised either as a ‘stand-alone’ fence, or can be installed as short
sections along a standard temporary fence. Though far less expensive than either the semipermanent or permanent designs, this type of fence must be very carefully installed and
maintained to prevent damage to the membrane. In particular, the mounding against the
membrane needs to comprise loose, light unconsolidated spoil. Where the fence is installed
on heavy soil, this can be partly replaced by cut vegetation.
If the ground conditions are such that the trench cannot be backfilled effectively, then the
membrane may be laid on the ground surface and soil can be mounded on top of it. If this
method is used, then the mounded material must extend far enough beyond the membrane to
act as sufficient barrier.
In addition, where ground conditions are soft, it may be necessary to support the fence with
additional posts periodically along its length.
VOLUME 10 SECTION 4
PART 7 HA 116/05
Heavy duty plastic membrane to
take weight of backfill without
tearing or stretching. (Minimum
roll width: 1200 mm.)
19x38x500 mm rough sawn (RS)
softwood batten; attached to post
with 50 mm nails, sandwiching
the membrane.
50x50x1200 mm RS softwood
post set approximately 30° from
vertical, so that reptiles cannot
climb the fence. Post spacing at
1 m intervals.
Light, unconsolidated backfill and
additional material piled up on
membrane to allow reptiles to
climb and cross the fence from
this direction. Care should be
taken to ensure the membrane is
not torn or overloaded with
material.
700 mm
600 mm
150 mm
Membrane placed in trench and
backfilled to provide an
underground 'return'.
MAY 2005
B/2
ANNEX B
DESIGN OF REPTILE-PROOF FENCING
VOLUME 10 SECTION 4
PART 7 HA 116/05
Semi-permanent Reptile Fencing: Free-standing or attached to boundary fences
Specification for standard post
and rail designs should be sought
from MCHW (Volume 3, Section
1, Series H). The fence shown is
of a four rail design (MCHW as
above, Drawing H3).
Other
specifications may also the
appropriate - but the height of
membrane supporting rail should
not be less than 600 mm.
2 mm thick HDPE sheeting is a material which has been used to create effective semipermanent reptile barriers. Although the membrane material is relatively expensive, these
fences can be easy to install, potentially buried using a modified plough rather than a trench.
The use of this kind of membrane also produces a more robust fence than the lighter-weight
membranes and generally do not need to be protected by additional fences (however they
tend to be marginally less robust than part-buried ‘half-pipe’ designs).
This fence design can be used in conjunction with timber post and rail highway boundary
fencing, or as a stand-alone fence. The diagrams below show both of these alternatives. (It is
also possible to install the membrane clear of the post footings due to the flexible nature of the
materials.)
50x50x1200 mm rough
sawn (RS) softwood post.
19x38 mm rough sawn (RS)
softwood batten; attached to
membrane supporting rail using
50 mm nails.
19x38 mm RS softwood batten,
continually attached to
membrane supporting rail using
50 mm nails.
87mm
Overhang - approximately 250
mm.
225mm
624 mm
Membrane supporting rail (e.g.
58x87 mm RS softwood)
attached to post using 50 mm
nails.
600 mm
250 mm
MAY 2005
2 mm thick HDPE provides a
robust fencing membrane which
is relatively damage resistant.
The thickness/weight of the
material allows the overhang to
remain effective, although
unsupported.
Backfill compacted to ensure no
fissures or gaps remain around
the membrane.
Overhang - approximately 250
mm.
Membrane supporting rail (e.g.
38x87 mm RS softwood) attached
to existing rail using (minimum) 50
mm nails.
87mm
225 mm
2 mm thick HDPE provides a
robust fencing membrane which is
relatively damage resistant. The
thickness/weight of the material
allows the overhang to remain
effective, although unsupported.
250 mm
Backfill compacted to ensure no
fissures or gaps remain around
the membrane.
B/3
ANNEX B
DESIGN OF REPTILE-PROOF FENCING
VOLUME 10 SECTION 4
PART 7 HA 116/05
Semi-permanent One-way Reptile Fence
Modular Reptile Fence Design
This fence design, utilising twin-wall plastic drainage pipe, is more cost-effective than that of
the permanent solution overleaf, but is comparably robust when well constructed. It is also a
more effective design than temporary membrane fences in situations where damage is likely
to occur, and generally does not require a second protective fence except in areas where plant
is operating very close to the fence. In addition, this design is more effective in allowing
reptiles to negotiate the fence in one direction and is far less visually obtrusive. It can be
useful as a short section in a longer membrane fence where animals (such as badgers) may
damage a membrane fence, or in strategic locations to allow the one-way movement of
reptiles. In addition, it represents a more robust alternative where a temporary fence is
required to cross particularly difficult ground conditions.
This type of reptile fencing is a new design, but provides a versatile system which is easy to
install. It may be used as a vertical (as shown) or angled, one-way design, and is constructed
from ready-made polypropylene sheets held in place by galvanised steel staples. Three
grades of sheeting are available, which are suitable for temporary installation, semi-permanent
installation and permanent installation respectively. Panels are also available in different sizes
– the diagram shows a fence suitable for the exclusion of slow-worms, but a larger size may
be more suitable for other species.
Upper edges of the panels folded to form anti-climb lip.
Shorter staple leg passes through holes in
overlapping panels.
Section of 600mm diameter twin-wall
plastic drainage pipe, cut in half
longitudinally.
250 mm
Lower edges of panels folded out to form
buried return.
Mounded backfill material
allows reptiles to cross the
fence from this side.
3-D diagram of fence design
600 mm
Minimum
400 mm
Backfill and existing ground
kept low to reduce the
likelihood of vegetation
regrowth reaching the upper
edge of the fence.
Staple with lifting/
jacking eye.
300 mm
Cut away view of
fence panel.
100 mm
3000 mm
Backfill compacted to hold the pipe
section in position. In soft conditions, or
ground that is difficult to compact, a
greater depth of backfill may have to be
used (but ideally this should not reach
within 400 mm from the top of the fence).
Patented GB2393894
All rights reserved.
MAY 2005
B/4
ANNEX B
DESIGN OF REPTILE-PROOF FENCING
Permanent One-way Reptile Fence
VOLUME 10 SECTION 4
PART 7 HA 116/05
General Notes on Reptile Fencing
This type of fencing design is designed to be used in those few situations where a permanent
reptile-proof barrier is required. It is constructed using purpose-built moulded plastic panels,
with anchoring pins and supports. This design also allows reptiles to cross in one direction by
climbing up the mounded ramp. Once vegetation has grown over the soil ramp this design has
a very low visual impact. Regular maintenance is required to ensure that vegetation does not
grow up in front of the fence and compromise the integrity of the barrier (this is important for
all fence designs, but is of particular importance for fences which are to remain in situ for long
periods).
z All reptile fences must be checked regularly and maintained to ensure they remain fully
effective throughout their working life.
z All fence designs require some degree of backfilling of trenches or spaces beside the
fence membrane, or mounding of earth. The substrate used for this should be friable and,
in the case of back-fill, firmly compacted to prevent the formation of any gaps or fissures
which reptiles may use to find a route beneath the fence, or as a refuge. Where available
substrates are not sufficiently loose or able to be compacted, additional materials should
be imported to ensure a reptile-proof barrier is maintained.
z In all fence designs, all timber should be untreated rough sawn (RS) softwood obtained
from a renewable source.
Purpose-built curved fence
panels form continuous reptileproof barrier.
z Modular fencing panels and ‘half-pipe’ fencing may be re-used or recycled (provided they
are appropriately installed), providing a significant cost saving on, for example, phased
development sites.
Soil mounded to form a ramp.
z The precise fence design and specifications should be ‘tailored’ to the reptile species
concerned. For example, where common lizards need to be excluded, the taller fence
options need to be chosen, with an effective top return throughout, and particular effort
needs to be directed at avoiding vegetation falling against or over the fence. Where slowworms alone are concerned, lower fencing options can be considered, and most attention
needs to be given to the compaction of backfill and the maintenance of an effective
below-ground barrier, particularly on uneven surfaces.
450 mm
z The majority of these reptile-proof fencing solutions are equally applicable as temporary,
semi-permanent and permanent fencing in the context of mitigation schemes for
amphibians.
z Permanent one-way fencing should be in place before the road opens.
Anchoring pin.
430 mm
Supporting post.
MAY 2005
B/5
ANNEX C
ARTIFICIAL REFUGE SPECIFICATION
VOLUME 10 SECTION 4
PART 7 HA 116/05
Artificial refuges are used as part of the combination reptile survey methodology as described
in Paragraph 6.2.3. They represent structures which act as a place of shelter from predation
and disturbance, and as an aid in absorbing heat. It is the reptiles’ propensity to seek out such
structures that makes it possible to use artificial refuges for reptile survey purposes.
Artificial refuges for use in road verge reptile surveys should be produced from heavy-weight
flame-activated bitumen roofing felt. This is a robust material which is heavy enough to
prevent it from blowing up in the up-draught of passing vehicles. The heaviest grade of felt
should be used wherever possible. There is an advantage in using roofing felt without the
‘green mineral’ top coat. This is so that reptiles may be captured from the top of refuges
without risk of damage to the animal. The smooth side of the material should be used
underneath, to prevent damage to animals in contact with the felt when the refuge is lifted.
Although mineralised felt should be avoided if possible, often, it is the only finish available on
the heaviest of felts. Where it is used, extra care should be taken to avoid damaging any
animals captured when basking on top of the artificial refuges.
For reptile surveys away from the live carriageway, where artificial refuges will not represent a
hazard to passing traffic or members of the public, the use of corrugated metal and heavygauge rubber is recommended for at least some of the refuges. It has been reported by some
practitioners that the different conditions which these materials provide are preferentially
selected by some species of reptiles.
Common lizard basking on a roofing felt artificial refuge.
An appropriate minimum size of refuges for reptile survey and capture is 0.5 m2 (approximate
dimensions: 0.75 m x 0.75 m), however, some practitioners have recorded the preference by
snakes for larger refuges and higher capture rates for some other species, so in most cases a
range of refuge sizes should be used, including some larger ones.
When checking refuges, the surveyor should ensure that any reptiles are clear of the area
before replacing the refuge to prevent damage to the animals. The refuge may be replaced
whilst the animals are in the hand (if it is necessary to capture them), and then the animals
released at the edge of the refuge. For the purpose of surveys which unavoidably involve
captures, animals should always be released at the locations in which they were captured.
“Artificial refuges” may also be commonly referred to as “Artificial Cover Objects” (“A.C.O.s” or
“Cover Objects), “Tins” or “Refugia”.
An artificial refuge on the soft estate.
MAY 2005
C/1
ANNEX D
HIBERNACULA DESIGN
VOLUME 10 SECTION 4
PART 7 HA 116/05
Hibernaculum on free-draining ground
Hibernaculum on impermeable ground
Where ground conditions allow, the hibernaculum should be incorporated into a shallow pit.
This design is more likely to remain frost-free, and will be less obtrusive and thus unlikely to
be subject to interference.
Where ground conditions are impermeable, then an ‘above-ground’ or mounded design
should be utilised in order to prevent the hibernaculum from flooding. This design should also
be used if it is not possible to excavate a pit for any other reason.
The addition of a geotextile membrane may be
used to prevent erosion of the capping layer
into the cavities beneath. This would be
particularly important where the capping layer
is composed of topsoil or other loose material.
Hibernaculum is filled to just above ground
level, then capped with layer (50 - 100 mm
thick) of turf or moss. If neither is available,
topsoil may be used.
Mound capped with layer (50 - 100 mm
thick) of topsoil, turf or moss.
The addition of a geotextile membrane
beneath the capping layer may be used to
prevent soil, or other loose material, from
collapsing into the voids below.
Minimum
1000 mm
Mound constructed from piled up rocks,
logs, dead wood and other suitable rubble.
Soil can be loosely filled between layers
during construction. (Minimum area: 1500
x 1500 mm.)
500 1000 mm
500 mm
Pit excavated and loosely filled with
piled up rocks, logs, dead wood and
other suitable clean fill material.
Small amounts of soil can be
loosely filled between layers during
construction.
MAY 2005
Gaps left in capping material at ground
level to allow reptile access.
Hibernaculum should be constructed
on gentle slope to prevent flooding.
Gaps left in capping material at ground
level to allow reptile access.
D/1
ANNEX D
HIBERNACULA DESIGN
VOLUME 10 SECTION 4
PART 7 HA 116/05
Complex hibernaculum design
Fill material
Where particularly large or important populations of reptiles (particularly snakes) occur, it may
be appropriate to include a more complex habitat feature as an artificial hibernaculum. One
such design is shown below. It incorporates a hibernaculum designed to produce a range of
temperatures and humidity gradients during the winter to allow animals to move between their
optimum conditions; south-facing basking slopes to provide good quality conditions for
animals before and after hibernation, and a range of vegetation heights providing a mosaic of
areas of varying habitat structure.
This should ideally comprise a range of materials including pre-formed construction materials
such as air bricks, hollow concrete blocks and surplus concrete channel sections; clean stone
of a pH appropriate to the locality; and appropriate lengths of dead wood.
Banktop hedge (not continuous)
provides varied shade and
protection from aerial predators.
Earth and turf back-filled to
create roof to hibernaculum.
A geotextile membrane may be
used to prevent the erosion of
capping materials into the
hibernation chamber below.
Gap left in turf exposes fill
material to provide a large
number of access points to the
hibernaculum.
Fill material (see notes).
Variation in mowing heights
(minimum 150 mm) provides
structural variation of the habitat.
MAY 2005
South-facing bank created to
provide basking opportunities.
Base of trench gravel-filled for
drainage. This could incorporate
a perforated pipe or similar.
D/2
ANNEX E
DESK STUDY CONSULTEES
VOLUME 10 SECTION 4
PART 7 HA 116/05
Appropriate Authorities
Statutory Nature Conservation Organisations (SNCOs)
For the purposes of licensing development-related activities under the Conservation (Habitats
&c) Regulations (1994), the governmental departments who act as the ‘Appropriate Authority’
are as follows:
For the purposes of survey, education or ‘conservation-related’ activities associated with the
two rare species, the SNCO is the appropriate licensing body. The SNCO should also be
consulted with regard to development-related impact assessment and mitigation schemes
which involve sand lizards and smooth snakes, prior to any licence application. The SNCO
should be consulted on the design and implementation of significant mitigation schemes for
the widespread species also.
Development-related licences for sand lizards and smooth snakes in England:
The Licensing Officer
DEFRA
Zone 1/08
Temple Quay House
2 The Square
Temple Quay
Bristol
BS1 6EB
Tel:
0117 372 8903
Fax: 0117 372 8182
Web: http://www.Defra.gov.uk
English Nature
Northminster House
Peterborough
PE1 1UA
Tel:
Fax
Email:
Web:
01733 455 101
01733 455 103
[email protected]
http://www.english-nature.org.uk
Tel:
Fax:
Email:
Web:
0845 130 6229
01248 355 782
[email protected]
http://www.ccw.gov.uk
Tel:
Fax:
Email:
Web:
0131 447 4784
0131 446 2405
[email protected]
http://www.snh.org.uk
Countryside Council for Wales
Development related licences for sand lizards in Wales:
Environment Division
National Assembly for Wales
Cathays Park
Cardiff
CF10 2NQ
Tel:
Fax:
02920 82 3363
02920 80 1353
Maes-y-Ffynnon
Penrhosgarnedd
Bangor Gwynedd
LL57 2DW
Scottish Natural Heritage
Anderson Place
Edinburgh
EH6 5NP
Environment and Heritage Service (Northern Ireland); Natural Heritage
Commonwealth House
35 Castle Street
Belfast
County Antrim
Northern Ireland
BT1 1GU
MAY 2005
Tel:
02890 251 477
Web: www.ehsni.gov.uk
E/1
ANNEX E
DESK STUDY CONSULTEES
Desk Study Consultees
As part of the Stage 1 Desk Study and subsequent consultations at Stages 2 and 3, ecological
data, including specific information on reptiles should be obtained from: the Statutory Nature
Conservation Organisations, Local Authorities, Wildlife Trusts and Local Biological Records
Centres. In addition to this, and in particular in areas where reptiles appear to be underrecorded, it would be appropriate to contact the specialist groups listed below.
The Herpetological Conservation Trust
655A Christchurch Road
Boscombe, Bournemouth
Dorset
BH1 4AP
Tel:
Fax:
Email:
Web:
01202 391 319
01202 392 785
[email protected]
http://herpconstrust.org.uk/
Local Amphibian and Reptile Groups (ARGs), are likely to hold useful information regarding
local reptile distribution and abundance, and up-dated lists of ARG contacts can be found
through the Herpetofauna Groups of Britain and Ireland, at the website address given below.
Herpetofauna Groups of Britain and Ireland (HGBI)
c/o
Froglife
White Lodge
London Road
Peterborough
PE7 0LG
Tel:
Fax:
Email:
Web:
01733 558 844
01733 558 440
[email protected]
http://froglife.hostwith.me.uk/HGBI/HGBI.htm
And for local Amphibian and Reptile Groups (ARGs) around the country:
Web: http://froglife.hostwith.me.uk/HGBI/ARGs.htm
Froglife
White Lodge
London Road
Peterborough
PE7 0LG
VOLUME 10 SECTION 4
PART 7 HA 116/05
Tel:
Fax:
Email:
Web:
01733 558 844
01733 558 440
[email protected]
www.froglife.org
The British Herpetological Society
c/o
The Zoological Society of London
Regent’s Park
London
NW1 4RY
MAY 2005
Web: http://www.thebhs.org/
E/2
ANNEX F
PHOTOGRAPHIC EXAMPLES OF PRINCIPAL ISSUES
VOLUME 10 SECTION 4
PART 7 HA 116/05
The following photographs illustrate road verge features and elements of habitat structure
which are beneficial for reptiles:
The quality of habitat on the soft
estate can often be much higher
than in surrounding areas. Here, on
the A31 in the New Forest, the road
verge heathland habitats support
resident populations of smooth
snakes, adders, common lizards and
slow-worms, and are also used by
grass snakes. The verges represent
higher quality habitat than the
adjacent grazed heathland.
South-facing slopes on the verge of
the A417 near Gloucester. The
habitats comprise a mixture of
exposed substrates, grassland and
scrub. The structurally diverse habitat
provides varied opportunities for
basking, foraging and hibernating
reptiles. Healthy populations of
adders, common lizards and slowworms have been found here.
A similar example, farther south on
the A417, near Cirencester. Maturing
landscape planting, variations in
mowing heights and outcrops of
underlying rock combine to provide
a range of basking opportunities.
The verges of the M4 near Bristol also
illustrate a good diversity of
vegetation structure.
MAY 2005
Once again, healthy populations of
reptile species, particularly slowworms and grass snakes have been
recorded here.
F/1
ANNEX F
PHOTOGRAPHIC EXAMPLES OF PRINCIPAL ISSUES
VOLUME 10 SECTION 4
PART 7 HA 116/05
Drainage features within the soft estate (below) often provide
suitable conditions for reptiles. The variations in topography of
the surrounding banks mean that a number of aspects may be
created, thus creating basking opportunities throughout the day/
season. These features can also provide valuable foraging
opportunities, potential egg-laying sites for grass snakes
(particularly if cut vegetation is formed into compost heaps (inset)
nearby) and hibernacula.
Man-made features within the verges (such as those above,
top and left) can add to the opportunities for basking,
foraging and hibernating reptiles. Common lizards, slowworms, adders, smooth snakes and grass snakes have all
been recorded using the features illustrated here.
MAY 2005
F/2
ANNEX F
PHOTOGRAPHIC EXAMPLES OF PRINCIPAL ISSUES
VOLUME 10 SECTION 4
PART 7 HA 116/05
Log and brash piles provide cover, basking sites and refuges, and if sufficiently extensive and/or part-buried, may act as suitable hibernacula. Leaving tree stumps in situ allows the retention of
natural hibernacula between the roots and as the stumps rot, more cavities may be created.
MAY 2005
F/3
ANNEX G
DECISION MATRIX
VOLUME 10 SECTION 4
PART 7 HA 116/05
A decision matrix is set out on the following page, to help guide the choice of options for reptile
surveys, impact assessment and mitigation at the different stages of Environmental
Assessment for new road schemes (as defined in the DMRB (Vol. 11)).
Similar steps with regard to survey and assessment would be appropriate for works
associated with the existing road network, although generally the process is likely to be more
‘compressed’ and there are likely to be fewer options available at each equivalent phase.
MAY 2005
G/1
ANNEX G
DECISION MATRIX
VOLUME 10 SECTION 4
PART 7 HA 116/05
ASSESSMENT
STAGE 1
Do desk study records exist
for reptiles on sites that would be affected
by the proposals?
NO
From initial
map-based assessment, would habitats likely to support reptiles
be affected by the proposals?
YES
Could sand lizards or smooth snakes
be affected (on the basis of existing records or suitable habitat
within their known ranges)?
NO
YES
YES
NO
Can the areas in question be
avoided entirely by route choice
and alignment?
NO
YES
Seek to minimise likely impacts
on reptiles through route choice
and alignment
ASSESSMENT
STAGE 2
Seek to minimise likely impacts
on the most valuable reptile species
through route choice and alignment
Choose the options which avoid
impacts on smooth snakes and sand
lizards
Carry out initial reptile investigations in
multi-disciplinary walk-over surveys. Assess the
likely presence of different species; the value,
importance and functional significance of habitat
features; and scope all further surveys
Confirm findings of desk study/
map-based assessment in
multi-disciplinary walk-over surveys
Was the initial assessment
of no/minimal impacts on reptiles
correct?
Has the presence
of reptiles been confirmed
to date?
NO
YES
YES
Does the
information so far collected suggest
the presence of substantial reptile populations and/or 3
or more species?
YES
NO
ASSESSMENT
STAGE 3
Consider surveys, targeted on smooth
snakes and sand lizards to confirm their
presence or absence, and thus inform the
assessment of potential impacts and
mitigation design
Consider the need to up-date
or extend the desk-study
consultations
NO
Continue to develop mitigation
for potential impacts throughout
the design process
Undertake ‘routine’ reptile surveys to: confirm the
presence or absence of each species; their distribution in
relation to the route corridor; assess the population
viability; identify important features; assess the likely
value of habitats; and scope any further surveys
Do the proposals have a substantial
effect on an important population and/or one or
more key features?
Attempt to put the assemblage into a
local/regional context
NO
YES
Can these be avoided
by refinements to route design
or alignment?
NO
YES
No further surveys nor detailed
mitigation measures required.
Consider the need for limited,
precautionary measures to avoid
the incidental mortality of reptiles
MAY 2005
Assuming that the appropriate revisions
are made, no further investigations are
required
Consider more detailed surveys to inform impact assessment, mitigation and
monitoring, potentially including:
- Detailed population size estimates
- Assessing reptile distribution (on and adjacent to the sites affected)
- Identification of potentially important features and the confirmation of their use
- Assess seasonal use of sites/habitat features
- Apparent viability of the populations
- Surveys of potential receptor areas
Proceed to impact assessment and
mitigation design
Begin/continue detailed surveys,
comprehensive impact assessment
and mitigation design in consultation
with SNCO
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ANNEX H
ACKNOWLEDGEMENTS
VOLUME 10 SECTION 4
PART 7 HA 116/05
This Advice Note was prepared for the Highways Agency by Cresswell Associates
(Environmental Consultants) Ltd. Those particularly involved with the project were Warren
Cresswell, Robin Jones, Philip Davidson, James Latham, Rhiannon Whitworth and our
Associate, Roger Avery.
We are grateful to David Griffiths, Stuart Wilson and their colleagues within the Highways
Agency who assisted with the development of the Advice Note.
Particular thanks are due to the Herpetological Conservation Trust, notably Tony Gent and
Chris Gleed-Owen, who formed part of the Steering Committee for this project and helped
guide the production of this Advice Note.
The HA Technical Project Board provided a number of helpful comments on the drafts of this
Advice Note. In addition, we are particularly grateful to Jim Foster (English Nature) for his
constructive comments.
A number of consultees provided information and assistance in the early stages in the
development of this project, largely in response to our initial questionnaire survey. We would
like to thank each of the respondents, in particular Tony Phelps for his helpful comments, and
Peter Goble for all his help at the earlier stages of the fieldwork which helped underpin this
Advice Note. We are grateful also to each of the Managing Agents who provided useful
information on reptiles and management activities within the soft estate.
All photographs by Cresswell Associates, except:
Figure 4.3, photographs (c), (e) and (f) were kindly provided by Paul Edgar, HCT.
Illustrations by Patrick James (Cresswell Associates).
MAY 2005
H/1
ANNEX I
FURTHER READING
General
Baker, J., et al (2004) English Nature Research Report No. 546: Status of the adder Vipera
berus and slow-worm Anguis fragilis in England. English Nature, Peterborough.
Beebee, T. and Griffiths, R. (2000) New Naturalist No. 87: Amphibians and Reptiles. Harper
Collins Publishers, London.
VOLUME 10 SECTION 4
PART 7 HA 116/05
Bullock, J.M., Hodder, K.H., Manchester, S.J. and Stevenson, M.J. (1997) JNCC Report No.
261: Review of information, policy and legislation on species translocation. Joint Nature
Conservation Committee, Peterborough.
English Nature (1994b) Roads and nature conservation. Guidance on impacts, mitigation and
enhancement. English Nature, Peterborough.
English Nature (2004) Reptiles: Guidelines for Developers. English Nature, Peterborough.
English Nature (1994a; and updates) Species Conservation Handbook: English Nature,
Peterborough.
English Nature (2005) Reptile Mitigation Guidelines. English Nature, Peterborough.
Gent, T. and Gibson, S. (2003) Herpetofauna Workers Manual. Joint Nature Conservation
Committee, Peterborough.
Herpetofauna Groups of Britain and Ireland (1998) Evaluating local mitigation/translocation
programmes: Maintaining Best Practice and lawful standards. HGBI advisory notes for
Amphibian and Reptile Groups (ARGs). HGBI, c/o Froglife, Halesworth. Unpubl.
Joint Nature Conservancy Council (1990) Handbook for Phase 1 habitat survey - a technique
for environmental audit. JNCC, Peterborough.
Joint Nature Conservation Committee (1994) A framework for the conservation of Amphibians
and Reptiles in the UK: 1994-1999. Joint Nature Conservation Committee, Peterborough.
Joint Nature Conservation Committee (2004) Common Standards Monitoring guidance for
reptiles and amphibians. Joint Nature Conservation Committee, Peterborough.
Moulton, N. and Corbett, K. (1999) The sand lizard conservation handbook. English Nature,
Peterborough.
Roberts, P. et al (1999) A guide to the reptiles and amphibians of Britain and Ireland. Field
Studies Council, Shrewsbury.
Habitat Management
Platenberg, R. J. and Griffiths, R. A. (1999) Translocation of slow-worms (Anguis fragilis) as a
mitigation strategy: a case study from south-east England. Biological Conservation, 90: 125132.
Reinert, H.K. (1991) Translocation as a conservation strategy for amphibians and reptiles:
some comments, concerns and observations. Herpetologica 47: 357-363.
Stebbings, R.E. (2000) Reptile Hibernacula – providing a winter refuge. Enact, 8(2): 4-7.
English Nature, Peterborough.
Survey Techniques
Barker, Mike A. and Hobson, Desmond D. (1996) Artificial Refuges with Transects as a
Possible Reptile Survey Methodology. The British Herpetological Society Bulletin 55: 8.
English Nature (1996) Management of bare ground on dry grasslands and heathlands
(Leaflet). English Nature, Peterborough.
Foster, J. and Gent, T. Eds. (1996) English Nature Science Series No. 27: Reptile survey
methods (Proceedings of a seminar held on 27 November 1995 at the Zoological Society of
London’s meeting rooms). English Nature, Peterborough.
Froglife (undated) Froglife Advice Sheet No. 6: Conserving Grass Snakes. Froglife,
Halesworth.
Froglife (1999) Froglife Advice Sheet 10: Reptile Survey: An introduction to planning,
conducting and interpreting surveys for snake and lizard conservation. Froglife, Halesworth.
Mitigation
Reading, C.J. (1996) English Nature Research Report No. 200: Evaluation of Reptile Survey
Methodologies. English Nature, Peterborough.
Bray, R. & Gent, T. Eds. (1997) English Nature Science Series No. 30: Opportunities for
amphibians and reptiles in the designed landscape (Proceedings of a seminar at Kew
Gardens, Richmond, Surrey held on 24 January 1996). English Nature, Peterborough.
Reading, C.J. (1997) A proposed standard method for surveying reptiles on dry lowland heath.
Journal of Applied Ecology 34: 1057-1069.
Sheldon, S. and Bradley, C. (1989) Identification of individual adders (Vipera berus) by their
head markings. Herpetological Journal 1: 392-395.
MAY 2005
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ANNEX J
GLOSSARY
VOLUME 10 SECTION 4
PART 7 HA 116/05
Adult
Sexually mature.
Penial bulge
Assemblage
The collective term for all of the species of a given group of
animals or plants present within a given area – e.g. a “reptile
assemblage” refers to the total number of all reptiles within an
area.
Simply the area in which a male reptile’s reproductive organs are
found. The presence of the bulge (either observable or by
‘palpation’ – gentle squeezing between the thumb and forefinger)
is therefore used to differentiate between males and females.
Phase 1 habitat survey
A standard survey methodology which is used used to classify
and map habitat types in the UK.
The degree to which a species is rare, uncommon or declining on
a national, regional or local basis.
PIT tags
A mathematical model used to predict an ‘end date’and/or total
population size, undertaken in association with a capture and
removal (translocation/relocation) programme.
“Passive Integrated Transponder (PIT)”. PIT tags are small
identification chips that may be inserted into an animal’s body
(usually under the skin) to enable individual identification.
Receptor site
The specific site to which translocated animals are moved. (Also
see “Donor” site.)
The site from which animals are captured and translocated (also
see “Receptor site”).
Soft-release
A technique employed when releasing captive or translocated
animals so that they may become accustomed to their new
surroundings. Often for reptiles, this may involve the placing the
animals in an area surrounded by temporary reptile-proof fencing,
possibly also combined with protection from predators and/or
enhancements to their immediate habitat to promote their
survival, so that they are only fully released when the fences are
removed.
Site of Special Scientific
Interest (SSSI)
A site of national importance designated on the basis of nature
conservation or geological value.
Sub-adult
This is intended to refer to the period of life between the juvenile
stage and when animals reach sexual maturity, thereafter referred
to as adults (see also “Juvenile” and “Adult”).
Sub-caudal scale
The scales found along the underside of a reptile’s tail.
Sub-cutaneously
Meaning: ‘beneath the skin’.
Transect
In the context of reptile surveys, the term ‘transect’ is used for the
route of a survey walk (or line of artificial refuges) which is biased
to the habitat types and specific features of the habitats in which
reptiles are most likely to be found/observed. By using such a
route, the likelihood of detecting the presence of reptiles is
maximised. By comparing the results from transects of equivalent
lengths and structure, it is also possible to generate broadly
comparable data between sample sites/schemes.
Conservation status
Depletion models
Donor site
Gravid
Pregnant; carrying developing young or eggs.
HABAP
Highways Agency Biodiversity Action Plan (England).
Herpetofauna
The collective term for reptiles and amphibians.
Herpetology
The branch of science which studies the natural history of reptiles
and amphibians.
Hibernaculum
Any place of shelter/protective structure occupied by an animal
during its hibernation period (plural: ‘Hibernacula”).
Juvenile
This is intended to refer to animals in their first year of life
(i.e. from hatching/birth to summer of following year).
Keel
The central ridge found on reptile scales. Note: Smooth snakes
do not have keeled scales – and are hence ‘smooth’.
Key Reptile Site
A site which appears on the ‘Key Reptile Site Register’. That is,
any site which fulfils the criteria set out in Froglife Advice Sheet
10: Reptile Survey, on the basis of its reptile assemblage.
Oviparous
The term which describes animals which produce eggs that
develop and hatch outside the mother’s body. Only two of the
UK’s native species are egg-laying: the sand lizard and grass
snake. (Also see “Viviparous”.)
MAY 2005
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ANNEX J
GLOSSARY
Translocation
The capture and release of animals from one site to another. (In
the context of this document “translocation” is used when referring
to the movement of animals from one site to another; “relocation”
is used when referring to the movement (capture and release) of
animals within a defined site.)
TRBAP
Trunk Road Biodiversity Action Plan (Scotland).
TREBAP
Trunk Road Estate Biodiversity Action Plan (Wales).
Ventral
Term used when referring to the under-side of an animal.
Vertebral
Term used when referring to the centre of an animal’s back
(– along its vertebrae).
Viviparous
The term used to describe animals which give birth to live young
(also see “Oviparous”). In the UK, common lizards, slow-worms,
adders and smooth snakes are viviparous.
MAY 2005
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