ECoW Field Training Guide

Ecological Clerk of Works

On-Site Practice and Species Guidance

For internal training use. Not for onward distribution.

Version 13 | May 2026

Seasonal Constraints Calendar

Month-by-month ecological timing constraints across all species covered in this guide. Tap any cell for guidance. The current month is highlighted with a dark border.

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1. The ECoW Role

Illustrations and Governing Body Guidance

The photographs and illustrations used throughout this guide are for illustrative purposes only. Species identification features, habitat conditions, and site circumstances vary considerably; field practitioners should treat visual examples as a general reference and not as a substitute for direct professional training or site-specific judgement.

Guidance, legislation, and best practice evolve continuously. Before undertaking any ecological survey or mitigation work, practitioners must consult the relevant governing bodies and refer to the most current published guidance. Key organisations and resources are signposted at the end of each section throughout this guide. The primary professional standard-setter for ecological consultancy in the UK is the Chartered Institute of Ecology and Environmental Management (CIEEM), whose ECoW guidance and factsheets should be consulted alongside any site-specific requirements set out in the ecological appraisal or Construction Environmental Management Plan (CEMP).

1.1 What an ECoW Does

An Ecological Clerk of Works (ECoW) is the qualified ecologist responsible for on-site ecological compliance during construction, clearance, and enabling works. The role sits between the ecological design team (who prepare reports, surveys, and licence applications) and the contractor (who carries out the physical works). The ECoW translates ecological conditions and constraints into practical, operational instruction on site.

The ECoW role is not advisory. Where a licence condition, planning condition, or method statement requires works to stop or to proceed only after specific checks, the ECoW has the authority — and the legal duty — to enforce that. Contractors who override an ECoW instruction are potentially committing a criminal offence under the Habitats Regulations 2017 or the Wildlife & Countryside Act 1981.

1.2 Core Responsibilities

Pre-works: review all ecological survey reports, the CEMP, and any relevant licences before setting foot on site. Know what species are present, what conditions apply, and what surveys are still valid.

On-site: supervise vegetation clearance, topsoil strip, and any ground disturbance with ecological risk. Conduct species checks immediately before the relevant operation. Halt works when a protected species or unexpected constraint is found.

Recording: maintain a site diary with dated entries for every site visit, every check, and every incident. Complete the required forms for any licences active on site. Photograph all relevant features, mitigation installations, and incidents.

Reporting: submit the ECoW record to the supervising ecologist as required and flag any compliance breach to the site manager and supervising ecologist immediately. Do not resolve a potential breach without informing the relevant party.

1.3 Biodiversity Net Gain (BNG)

The Environment Act 2021 introduced mandatory BNG for most development in England, requiring a minimum 10% biodiversity gain measured against the pre-development baseline using the DEFRA Biodiversity Metric. BNG obligations are secured through planning conditions or a Biodiversity Gain Plan.

The ECoW role in BNG delivery is principally to protect and verify. Retained habitats contributing to the baseline must not be damaged during construction — any loss reduces the net gain calculation and may breach planning conditions. Compensation and enhancement habitats specified in the Biodiversity Gain Plan must be installed to specification and recorded for compliance purposes.

The ECoW is not responsible for calculating the BNG metric or drafting the Gain Plan. The role is to ensure that what has been agreed on paper is delivered on the ground.

1.4 Toolbox Talks

A toolbox talk is a short, focused briefing given to site operatives before they begin work. For the ECoW, the toolbox talk is one of the most important compliance tools available — it translates the contents of a CEMP or method statement into instructions that the people actually operating the plant can act on.

Deliver an initial environmental toolbox talk before any ecologically sensitive works begin. Cover: which protected species are relevant to the works; what to do if an animal is found (stop, do not touch, call the ECoW); which areas are exclusion zones; and what the consequences of non-compliance are. Obtain a signed attendance record for every operative present.

Repeat the toolbox talk when new operatives arrive on site, when works move into a new sensitive area, and at the start of any new phase. A signed record is essential — it demonstrates that the ECoW has discharged the communication duty under the licence or CEMP.

2. Golden Rules

These rules apply on every site, without exception. They take precedence over programme pressure, contractor convenience, and the site manager's instructions.

1. If you are uncertain, stop. Do not allow works to proceed past a point of ecological uncertainty. The cost of a delay is manageable. The cost of a licence breach is not.

2. Record everything. Date, time, location, what you observed, what you instructed, and who was present. A verbal instruction with no record is worthless in an enforcement investigation.

3. Pre-clearance checks are mandatory. No vegetation, topsoil, or structure clearance without the species-specific check immediately before works. Not the day before. Immediately before.

4. Trench ramps are not optional. Any excavation left open overnight must have an escape ramp. Check this at the end of every working day.

5. Biosecurity before and after every site. Check, clean, and dry all equipment. INNS and wildlife disease do not respect site boundaries.

6. Do not handle protected animals without a licence. The ECoW role is to stop works and contact the supervising ecologist or licence holder. Handling is not within the ECoW remit unless you hold the relevant licence personally.

7. The 24-hour rule. Any potential breach of a licence condition or wildlife law must be reported to the supervising ecologist within 24 hours. Do not wait to see whether an animal recovers. Do not decide for yourself that the incident was minor.

8. Exclusion zones are physical boundaries. Fencing must be in place before works start, not added later. Walk the exclusion zones at the start of every working day to check for damage, encroachment, or new activity.

3. Construction Phases and ECoW Responsibilities

The ecological risk profile of a construction project changes substantially from one phase to the next. Understanding the build programme is not optional — it is a core ECoW competency. An ECoW who does not know what is happening on site in the coming days cannot anticipate constraints, cannot ensure surveys are still current, and cannot prevent programme delays caused by ecological non-compliance discovered too late.

The three formal phases recognised in ECoW good practice guidance are pre-construction, construction, and post-construction. Within the construction phase, different sub-phases carry fundamentally different ecological risks. The sections below describe the ECoW role at each stage.

3.1 Early Engagement: Design and Programming

The most common failure in ECoW practice is late appointment. When an ECoW is engaged only after a design is finalised and construction has been programmed, ecological constraints have to be retrofitted into a fixed sequence — which creates delays, cost, and risk. Best practice is for the ECoW to be involved at pre-construction design stage, when construction methods, access routes, and programme sequencing can still be shaped by ecological knowledge.

Early ECoW input prevents predictable problems: a contractor scheduling vegetation clearance in April because it fits the programme, not knowing it falls within the nesting season; a watercourse crossing designed without otter ledges that then requires a redesign under licence; a ground investigation borehole sited within an active badger sett exclusion zone. These are not unusual scenarios — they are the routine consequence of ecological advice arriving after decisions are already made.

At design stage, the ECoW should review the construction programme against: seasonal survey windows and licence conditions; species-specific timing restrictions (see section 3.4); the location of confirmed or potential protected species features relative to the construction footprint and access routes; and any survey validity requirements (most species surveys have a defined validity period, typically two to five years, after which resurvey is needed before works can proceed).

3.2 Pre-Construction Phase

The pre-construction phase begins when the client appoints the ECoW and ends when physical works start. It includes the pre-start period for any enabling works, site investigation, and vegetation clearance — activities that are frequently overlooked but carry high ecological risk. The ECoW must be appointed before any enabling works begin, not just before the main construction contract starts.

Pre-construction responsibilities include: reviewing all ecological survey reports, licence conditions, and the CEMP; confirming that all required licences are in place and have not expired; checking that no material change to the site has occurred since the surveys were carried out (seasonal changes, new colonisation, changed land management); and identifying any surveys that need to be updated before works can proceed.

Physical pre-construction tasks include: installing tree protection fencing and verifying its position against the BS 5837 Root Protection Areas before any ground disturbance; erecting ecological exclusion fencing around confirmed badger setts, bat roosts (where licence conditions require it), ancient woodland buffers, and any other protected features; installing reptile soft fencing if a displacement programme is planned; and placing pitfall traps if a GCN licence is active.

Attend and contribute to the pre-start meeting. Confirm the construction programme with the site manager and identify the first operations that will require ecological supervision. Agree a signal or protocol for stopping works (a clear agreed method is more effective than shouting across a noisy site). Deliver the initial environmental toolbox talk and obtain signed attendance records before any operative begins work.

3.3 Archaeological Evaluation and Trial Trenching

Archaeological evaluation trenching is a condition attached to many planning consents. It is carried out under a Written Scheme of Investigation (WSI) approved by the LPA, typically before site clearance or main groundworks. A field archaeologist holds the watching brief for unexpected archaeological finds. The ECoW and the archaeologist are distinct roles with concurrent, non-overlapping responsibilities: the ECoW is not qualified to make archaeological judgements, and the archaeologist is not qualified to direct the ecological response. Both must be clear on this before excavation begins.

Evaluation trenching uses a 360-degree excavator fitted with a toothless grading bucket to remove topsoil in narrow trenches, typically covering 5% of the application area. This creates the same ecological hazards as any mechanical ground disturbance: open trenches, spoil heaps, topsoil displacement, and tracked machinery crossing the site. The ECoW's obligations apply fully throughout this phase.

Before trenching begins, the ECoW must: receive the trenching programme in advance and check trench alignments against the ecological constraints map. Any trench that crosses an RPA, an INNS-contaminated zone, a reptile exclusion area, a GCN pitfall trap line, or a badger sett buffer must be flagged before the excavator moves. A trench alignment is far easier to shift on paper than on the ground.

During trenching: trench ramps must be installed in every open trench left overnight, as for any construction excavation. Spoil heaps from topsoil removal become informal refuges for reptiles within days in warm weather — any heap left in place for more than two weeks must be checked by the ECoW before it is disturbed or removed. Where pitfall traps are active on site, coordinate the morning trap check schedule with the excavation programme to avoid works starting before traps have been cleared.

INNS management during trenching requires specific coordination. The archaeologist's priority is preserving stratigraphic integrity; the ECoW's is preventing contaminated material leaving the site mixed with clean spoil. Agree the protocol for identifying, marking, and segregating INNS-contaminated soils before excavation begins. The spoil management plan agreed with the contractor must specify separate stockpile areas for INNS-contaminated material.

Trenching is sometimes carried out on uncleared, vegetated land — particularly for phased evaluation ahead of a rolling programme. On vegetated land, nesting bird, reptile, and badger obligations apply simultaneously with the trenching programme. Checks immediately before the excavator moves into each new area are required in exactly the same way as for vegetation clearance.

If a protected species is encountered during topsoil removal — a reptile in the overburden, amphibians in damp subsoil, a small mammal in a spoil heap — the stop-works protocol applies regardless of whether it is the archaeologist or a ground operative who identifies it. Neither the archaeologist nor the site manager has authority to override the ECoW instruction to halt works until the supervising ecologist is contacted.

3.4 Site Clearance and Vegetation Removal

Site clearance — the removal of vegetation, topsoil, and surface features — carries the highest ecological risk of any construction phase. Most protected species incidents occur here. The ECoW must be present throughout all clearance operations on ecologically sensitive sites. This phase cannot be left unsupervised.

Species-specific pre-clearance checks required immediately before works begin (within the timescales listed):

Nesting birds: check within 48 hours of clearance of any scrub, hedgerow, trees, rank grassland, or any building/structure proposed for demolition. Nesting season is 1 February to 31 August, but year-round checks are advisable.

Bats: check trees and structures for roost features immediately before felling or demolition. If any bat roost feature (BRF) is present that has not been assessed by a licensed ecologist, the tree or structure cannot be worked until a BRF check is completed. This may require ladder access (up to 4 m) or a licensed tree climber.

Reptiles: check artificial refugia on the day of clearance within the soft-fenced exclusion zone. Displaced reptiles must be counted and recorded. Clearance should proceed from the outside of the area inward, or from one end, driving animals ahead of the machinery. Never strim or rotary-cut over refugia.

Badgers: check the clearance area and any access routes for new sett entrances or fresh activity within 48 hours of works. If new activity is found within the clearance area, stop and contact the supervising ecologist.

Dormice: where nest tubes are deployed as part of a DML, tubes must be checked on the day of vegetation removal in the relevant compartment. Clearance must not proceed if a dormouse is found in a tube.

Water voles and otters: re-check bankside vegetation for signs immediately before any clearance within the watercourse buffer zone. Signs present at survey stage may have expanded, or new signs may indicate colonisation since the survey.

INNS: before clearance begins, identify and mark all INNS (particularly Japanese Knotweed) to prevent spread via machinery, soil movement, or vegetation disposal. Agree spoil management and disposal routes with the site manager.

3.5 Demolition

Demolition of existing buildings, walls, and hard structures carries specific ecological risks, principally for bats and nesting birds.

If a pre-demolition bat survey has been carried out and confirmed no roost, works may proceed subject to licence conditions. If the survey identified a roost requiring a licence, confirm that the licence has been obtained and the method statement is being followed before demolition starts. Bat emergence surveys specified in a licence must be completed before demolition of the relevant structure — they cannot be skipped or deferred.

For nesting birds, check the structure on the day of demolition. Pay particular attention to: roof voids (Barn Owl, Stock Dove, Jackdaw); cavity walls (House Sparrow, Starling, Swift); and any vegetation growing on the structure. Swifts return to nest sites from late April; once present, demolition affecting the nest entrance must cease until the young have fledged (typically late July to August).

Demolition of farm buildings or barns should be treated as high-risk for both Barn Owl and bats regardless of what pre-demolition surveys showed — both species can move into structures quickly. A final visual check of the interior on the day, before the demolition crew begins, is minimum best practice.

3.6 Groundworks and Earthworks

Groundworks — bulk earthmoving, excavation, and installation of below-ground services — are the phase at which the risk shifts from habitat and species disturbance to species entrapment and incidental harm.

Any open excavation or trench left overnight must have a ramp installed — a slope of soil, sand, or timber that allows small mammals and amphibians to escape. A ramp at each end of a trench is best practice. This applies regardless of species — trench fatalities are a common cause of badger, hedgehog, and GCN mortality on construction sites.

Where a GCN licence is active, pitfall traps must be checked every morning before works begin and all captured GCN recorded and released. If traps cannot be checked (illness, absence), the supervising ecologist must be informed and traps closed.

Excavation near watercourses triggers otter and water vole obligations. Any work within the 5 m water vole buffer or 30 m otter vegetation clearance zone must be flagged with the supervising ecologist before the excavator moves in. Unexpected holts, burrows, or signs found during excavation are a stop-works trigger.

Tree root protection zones must be actively monitored during groundworks. Ground compaction from plant movement, water run-off from concrete works, and accidental trenching within RPAs are common causes of retained-tree failure discovered years after construction. The ECoW should flag any plant operation that comes within the RPA of a retained tree and ensure the site manager takes corrective action.

Topsoil stripped from the site should be segregated and managed correctly: clean topsoil for re-use in habitat creation; INNS-contaminated material for licensed disposal. Mixing contaminated and clean material is an offence under the Environmental Protection Act 1990.

3.7 Superstructure and Main Build

During the main build phase — once foundations are in and the structure is rising above ground — direct risk to most mobile species reduces. However, the ECoW role does not end. Key obligations in this phase:

Continue monitoring exclusion zones around retained ecological features (badger setts, bat roosts, trees). Construction creep — the gradual movement of site compounds, materials storage, and access routes — is a common way exclusion zones are compromised over time. Regular checks and reminders to the site manager are necessary throughout the build.

Lighting installed for construction activity (security lighting, floodlighting for extended working hours) must be directed away from bat roosts, commuting routes, and retained habitats. Advise the site manager on lighting direction and lux levels. Unshielded floodlights are frequently installed by contractors without ecological input — once in place and in use, changing them is difficult.

Materials stockpiles, rubble piles, and sand heaps left on site become informal refuges for reptiles, amphibians, and small mammals. Any stockpile that has been in place for two or more weeks in warm weather should be checked by the ECoW before disturbance or removal. Reptiles in particular will colonise warm south-facing rubble piles rapidly.

Check that the BNG compensation and mitigation habitat areas — retained grassland, planted hedgerows, created ponds, buffer zones — are not being encroached by construction activity. These areas are protected under the planning consent, and any damage to them needs to be recorded and reported.

3.8 Landscaping and Reinstatement

The landscaping phase is where BNG gain is delivered. It is also one of the most overlooked phases from an ECoW perspective — the main construction team has often demobilised and ecological oversight is reduced at exactly the point when habitat creation is happening.

Confirm that all species enhancement features specified under planning conditions or licence requirements are installed to specification: bat boxes (height, orientation, distance from lights), bird and owl boxes, hibernacula (log pile, rock pile, or purpose-built for reptiles and GCN), otter holts, hedgehog gaps in fencing, swift bricks. The ECoW should check each feature against the specification and photograph it for the compliance record.

Seeding and planting: confirm that specified species-rich seed mixes or native plant stock are used, not generic amenity grass or non-native ornamental planting. Verify that INNS — particularly Himalayan Balsam and knotweed — are not being accidentally reintroduced through contaminated topsoil or wildflower seed mixes with poor provenance. Check the seed supplier certificate.

INNS management continues in this phase. Newly created bare ground and disturbed soil is highly vulnerable to INNS colonisation. Monitor for knotweed regrowth from any soil disturbance, and for Himalayan Balsam on any disturbed bank or wet ground.

3.9 Post-Construction Monitoring

Post-construction monitoring under the ECoW remit is compliance monitoring — checking that the ecological mitigation specified in the consent has been delivered and is functioning. This is distinct from broader long-term ecological monitoring (species diversity trends, condition surveys), which may continue for years but does not require a qualified ECoW.

Compliance monitoring tasks typically include: confirming that all enhancement features are in place and undamaged; recording Year 1 habitat condition against the BNG baseline for any conditions requiring it; checking that management agreements (grassland cutting regimes, hedgerow management, pond management) are being followed; and reporting to the LPA or Natural England as required by planning conditions or licence terms.

For multi-year or multi-phase developments, the ECoW scope must be reviewed at the start of each new phase. Survey data ages out, populations change, and licence conditions written for Phase 1 may not adequately cover Phase 2 works. The ECoW should proactively raise this with the supervising ecologist and the client rather than assuming that earlier consents and surveys carry forward unchanged.

Incident reporting obligations do not end when construction finishes. If a licence condition requires post-construction monitoring and a breach is identified during that monitoring, the same 24-hour reporting obligation applies.

4. Bats

4.1 Legal Status

All 18 UK bat species are protected under the Habitats Regulations 2017 and the Wildlife & Countryside Act 1981 (as amended). It is an offence to: deliberately kill, injure, or take a bat; deliberately disturb a bat (including impairing its ability to survive, breed, or rear young); or damage, destroy, or obstruct access to a roost — whether or not bats are present at the time.

Roost destruction requires a European Protected Species (EPS) licence from Natural England. The ECoW must not proceed with any works affecting a potential roost without confirming that a valid licence is in place and that the method statement is being followed.

4.2 Identifying Roosts and Signs

Potential bat roost features and field signs on British trees (English Oak, Beech, Ash, Sycamore): loose bark, rot holes, cavities, and staining. Illustration: Eco Routes.

Common indicators of bat roosts include: bat droppings — small, dark, crumbly pellets 4–7 mm long that disintegrate to a powdery brown residue when squeezed (distinguishing them from firm mouse droppings); staining and grease marks around entry points; scratch marks on timber near roost access; dead bats or bat remains beneath a roost; and strong smell of ammonia in confined roost spaces.

In trees, look for: loose bark, woodpecker holes, knotholes, splits and cracks in limbs, ivy-covered trunks, and hollow sections. Any such feature is a potential roost until confirmed otherwise by a licensed ecologist.

4.3 Constraints on Site

If a Bat Roost Assessment (BRA) or survey report has been produced for the site, read it before work starts and understand which structures or trees have confirmed or potential roosts and what licence conditions apply.

Maintain a minimum 30-metre buffer between works and any confirmed roost unless the method statement specifies otherwise. Avoid directing artificial lighting at roosts or along known bat commuting routes (hedgerows, tree lines, watercourses). If lighting is unavoidable, use warm-white LEDs directed away from vegetation at the minimum necessary lux level.

4.4 During Works

If bats are found during vegetation or building clearance: stop works immediately, do not disturb the bat further, record the time and location, and call the supervising ecologist. If the bat is injured or grounded, contact the Bat Conservation Trust (BCT) National Helpline on 0345 1300 228 and follow their advice while awaiting the ecologist.

Bat emergence surveys may be required before demolition or tree removal. These can only be carried out by licensed surveyors. Do not allow works to proceed if emergence surveys were a licence condition and have not yet been completed.

4.5 Bat Boxes and Enhancement Features

Where bat boxes or integrated bat bricks are specified, their installation must comply with the specification: minimum 3 metres above ground; entrance at least 0.5 m from eaves, branches, or any ledge; preferably south-facing; entrance at least 5 m from external lights and 2 m from windows.

After installation, check that the entrance is clear of construction debris. Do not open, relocate, or disturb a bat box without a licensed ecologist present. Interfering with a bat roost (which a box may become) is a criminal offence. Tree-mounted boxes require vegetation management to maintain sun exposure.

4.6 Further Guidance and Training

Bats are protected under the Conservation of Habitats and Species Regulations 2017 and the Wildlife and Countryside Act 1981 (as amended). All bat work must be conducted within the scope of a valid Natural England mitigation licence, and any activities outside the scope of that licence must be referred back to the supervising ecologist immediately.

The primary governing body for bat conservation and professional guidance in Great Britain is the Bat Conservation Trust (BCT). The BCT Good Practice Guidelines for Bat Surveys (4th edition) is the definitive reference for survey methodology, roost characterisation, and mitigation standards. Practitioners should ensure they are using the current edition, as this guidance is periodically updated.

Training opportunities specifically relevant to this section include the BCT's professional training and conference programme, which covers roost assessment, emergence surveys, transect methodology, and licence-compliant mitigation. CIEEM also offers continuing professional development (CPD) events relevant to bat ecology.

5. Nesting Birds

5.1 Legal Status

All wild birds, their nests, and eggs are protected under Section 1 of the Wildlife & Countryside Act 1981 (as amended). It is an offence to: intentionally kill, injure, or take any wild bird; intentionally take, damage, or destroy the nest of any wild bird while it is in use or being built; or intentionally take or destroy an egg of any wild bird.

Schedule 1 of the WCA lists species afforded additional protection — it is an offence to intentionally or recklessly disturb these birds at or near an active nest. Schedule 1 species likely to be encountered on development sites include Barn Owl, Peregrine Falcon, Kingfisher, all harrier species, and Hobby.

5.2 The Nesting Season

The main nesting season in the UK runs from 1 February to 31 August, though nesting can begin earlier and extend later depending on species and weather. Some species (notably Barn Owl) may breed outside this window. The safest approach is to treat any bird showing breeding behaviour — nest building, territorial song, carrying food — as actively nesting, regardless of date.

Vegetation clearance and building/structure demolition should be completed outside the nesting season wherever possible. If works cannot avoid the nesting season, a check by a competent ecologist must be carried out immediately before clearance — within 48 hours.

5.3 Constraints on Site

If a nest is found during clearance, stop works in the vicinity immediately and maintain a minimum 3-metre exclusion zone around the nest location. For Schedule 1 species, a wider buffer will be required and Natural England may need to be consulted. Works may only resume when a qualified ecologist has confirmed the nest is no longer active.

5.4 Barn Owls

Barn Owl (Tyto alba): habitat and field signs, including pellet analysis, nest box dimensions, and prey remains. Illustration: Eco Routes.

Barn Owls are a Schedule 1 species. They frequently occupy farm buildings, derelict structures, and large hollow trees. If a Barn Owl roost or nest is found, works must halt and Natural England must be contacted before any further action is taken.

5.5 Further Guidance and Training

Barn Owls are protected under Schedule 1 of the Wildlife and Countryside Act 1981 (as amended), meaning intentional or reckless disturbance at or near an active nest is a criminal offence. Any work that may affect a Barn Owl nest site requires a Natural England CL29 survey licence or a site-specific mitigation licence.

The Barn Owl Trust (BOT) is the primary governing body providing authoritative ecology and survey guidance for this species. The BOT offers the Barn Owl Ecology, Surveys and Signs (BOESS) course, which is the recognised training standard for ecological practitioners undertaking barn owl assessments. Completion of BOESS (or equivalent training accepted by Natural England) is typically required before applying for a CL29 survey licence.

General wild bird legislation and best practice is overseen by the British Trust for Ornithology (BTO) and the Royal Society for the Protection of Birds (RSPB). The BTO offers a professional training programme covering nest recording, bird survey techniques, and licensing requirements. Practitioners with knowledge gaps in bird ecology should consider formal BTO or BOT training before undertaking unsupervised barn owl work.

6. Badgers

6.1 Legal Status

Badgers and their setts are protected under the Protection of Badgers Act 1992 (PBA). It is an offence to: wilfully kill, injure, take, or cruelly ill-treat a badger; intentionally or recklessly interfere with a sett; or obstruct access to a sett. A sett is any structure or place used by badgers for shelter or protection — whether or not badgers are currently present. A licence from Natural England is required to disturb, close, or destroy a sett in connection with development.

6.2 Recognising Badger Setts and Field Signs

European Badger (Meles meles): sett types, habitat preferences, and field signs including hair snag, paw prints, latrine, feeding signs, and sett entrances. Illustration: Eco Routes.

Sett entrances are D-shaped or elliptical, typically 20–25 cm wide, with a large spoil heap outside active entrances, often with a clear furrow worn into it. Fresh bedding material near entrances is a strong indicator of current activity.

Signs of activity: smooth-worn runs (10–15 cm wide); latrines (dug pits at territory boundaries); kidney-shaped footprints 5–6 cm long, showing 5 toes with prominent claw marks; coarse hairs with a black sub-terminal band and white tip. Signs of inactivity: cobwebs across the entrance, undisturbed leaf litter, no fresh spoil.

6.3 Constraints on Works

A 30-metre exclusion zone must be maintained around active badger sett entrances. No plant, vehicles, or materials storage within this zone. The zone must be fenced before site clearance commences. Do not allow dogs on site near setts under any circumstances.

6.4 Sett Closures

Closure is permitted between 1 July and 30 November only, using one-way gates in place for a minimum of 21 days before sealing. Sett closure must be supervised by the licence holder. Any badger activity observed during or after the gate period must be reported to the supervising ecologist immediately.

6.5 Badger Activity Records and Reporting During Works

Throughout the gate period and immediately following sett closure, the ECoW must maintain a formal record of all monitoring activity. At the start and end of every working day during the gate period, check the condition of each gate: record the date, time, and observations in the site diary, and photograph every gate at least once per day. Note any signs of interference, disturbance to the soil around gate frames, or fresh spoil indicating digging activity.

Any fresh signs — scrape marks on gates, disturbed soil at entrances, fresh latrines within the buffer zone, or prints — must be reported to the supervising ecologist that same day, not at the end of the week. A badger found to have recolonised a gated sett or established a new entrance within the exclusion zone triggers an immediate stop-works requirement for any works within that zone.

Once the gate period is complete and the supervising ecologist has confirmed that the sett is inactive, the ECoW must submit a written gate period completion record before any works are permitted to commence within the former buffer zone. This record must include: dates gates were set and removed, photographic evidence, a summary of daily monitoring results, and the supervising ecologist's written confirmation that the closure is acceptable. Verbal confirmation is not sufficient for compliance purposes.

6.6 Further Guidance and Training

Badgers and their setts are protected under the Protection of Badgers Act 1992. Any activity that involves interfering with a sett, including closure, exclusion, or disturbance during active works, requires a licence from Natural England. Licence applications must be submitted by a suitably qualified ecologist and approved before works commence.

The Badger Trust is the leading charitable organisation for badger conservation and provides authoritative guidance on badger behaviour, sett identification, and planning obligations. Their development and planning guidance should be consulted when working on sites with badger activity. CIEEM also publishes best practice guidance relevant to badger surveys and mitigation.

Practitioners seeking formal training in badger survey techniques and licence-compliant mitigation should contact the Badger Trust or CIEEM for details of accredited courses. Where badger work is a recurring element of a practitioner's role, completion of a recognised badger survey course is strongly recommended before undertaking unsupervised assessments.

7. Reptiles

British reptiles and their ecology: all six native species with habitat preferences, seasonal behaviour, refugia use, and field signs. Illustration: Eco Routes.

7.1 Legal Status

Six native reptile species. Four widespread: Common Lizard, Slow Worm, Grass Snake, Adder. Two rare: Sand Lizard and Smooth Snake (EPS, Schedule 5). All six protected against intentional killing or injury. Sand Lizard and Smooth Snake additionally protected against disturbance and habitat damage.

7.2 Survey Conditions

Artificial refugia (ARs) are checked at 10–20°C between 07:00 and 18:00 in dry weather. Minimum six visits across the active season (mid-March to October), with at least two in April–May.

7.3 Mitigation

Phased habitat removal combined with soft fencing and displacement using ARs. Receptor habitat must be ready before displacement begins. Clearance proceeds from the centre outward. No strimming over refugia.

7.4 Adder Handling

The ECoW must not handle Adders under any circumstances. If encountered, mark location, move operatives away calmly, and contact the supervising ecologist.

7.5 Biosecurity — Disinfectants and COSHH

Both Virkon Aquatic and Agrichlor are classified H400/H410 (very toxic to aquatic life) and must never enter watercourses, drains, or ponds.

Virkon Aquatic: 1% solution — one 5 g tablet in 500 ml water. Discard when pink colour fades or after 7 days. Field disposal maximum 2 L per m2 on non-permeable ground away from water. PPE: nitrile gloves (EN374), safety glasses (EN166).

Agrichlor: 300 ppm for equipment (one tablet in 1.25 L); 630 ppm for footwear baths (one tablet in 2.5 L). Near watercourses, contain spray inside an upright bin bag and seal for disposal. Never make up solution beside open water. Additionally classified H272 (oxidiser) — store away from combustibles.

Apply the Check–Clean–Dry sequence to all survey equipment before and after each site visit.

7.6 Further Guidance and Training

Reptiles are protected under the Wildlife and Countryside Act 1981 (as amended), which makes it an offence to intentionally kill, injure, or trade in any native reptile species. Great Britain's four common reptile species (grass snake, adder, slow worm, and common lizard) are all subject to these protections, and Sand Lizard and Smooth Snake are additionally protected under Schedule 5.

The Amphibian and Reptile Conservation (ARC) Trust is the principal governing body for reptile conservation and best practice in the UK, and provides survey and mitigation guidance directly relevant to development. ARC offers a range of professional training courses covering translocation methodology, habitat management, and species identification. The Amphibian and Reptile Groups of the UK (ARG UK) is the network organisation for volunteer recording groups and publishes species-specific advice notes relevant to field identification and survey methodology.

Practitioners who conduct reptile translocations should hold, or be working towards, a recognised translocation qualification accepted by the supervising ecologist and the relevant licensing authority.

8. Great Crested Newts (GCN)

Great Crested Newt (Triturus cristatus): adult male and female, life cycle, pond-to-land ecology, and UK newt identification comparison. Illustration: Eco Routes.

8.1 Legal Status

European Protected Species under the Habitats Regulations 2017 and Schedule 5 WCA 1981. Offences: deliberate killing/injury/taking; deliberate disturbance; damage/destruction of breeding site or resting place. Penalty: unlimited fine and up to six months' imprisonment.

8.2 Survey Methodology

HSI applied to all ponds within 500 metres of the site boundary. Surveys in mid-March to mid-June, air and water above 5 degrees C, no preceding frost. Four methods: torch survey (minimum 50,000 cd), egg search, bottle trapping (one trap per 2 m shoreline, checked at dawn), refuge checks.

8.3 Terrestrial Habitat

GCN use terrestrial habitat within approximately 250 metres of the breeding pond. Licence conditions typically specify terrestrial buffer zones and receptor habitats as well as pond mitigation.

8.4 District Level Licensing (DLL)

The DLL scheme provides a strategic alternative to site-by-site EPS licensing for GCN in participating districts. Developers contribute to a habitat creation fund and receive a licence without site-level survey and mitigation.

8.5 During Works

If a GCN is found: stop immediately; do not handle; mark position; contact the supervising ecologist. Pitfall trap lines must be checked every morning without exception. If traps cannot be checked, notify the ecologist immediately and close or remove traps.

8.6 Further Guidance and Training

Great Crested Newts (GCN) are a European Protected Species listed under the Conservation of Habitats and Species Regulations 2017 and Schedule 5 of the Wildlife and Countryside Act 1981 (as amended). Any survey or mitigation work affecting GCN requires a valid Natural England mitigation licence or, in some areas, a District Level Licence. All trapping, handling, and translocation must be conducted by a licensed ecologist or under direct supervision.

Habitat Suitability Index (HSI) assessments for GCN use the ARG UK Habitat Suitability Index scoring system, and the ARG UK HSI calculator is the standard tool for quantifying pond suitability. Both resources are published by ARG UK and should be treated as current best practice references.

The ARC Trust and Froglife are the primary governing bodies for amphibian conservation and survey training. Froglife offers the Great Crested Newt Survey: Working Towards a Licence course, which is the standard pathway for practitioners seeking to become licensed GCN surveyors. Practitioners with knowledge gaps in amphibian ecology should complete this course before undertaking unsupervised GCN work.

9. Invasive Non-Native Species

9.1 Legal Framework

Schedule 9 WCA 1981: offence to plant, seed, or allow to spread in the wild. Common species on development sites: Japanese Knotweed, Himalayan Balsam, Giant Hogweed, Rhododendron. Soil containing Schedule 9 plant species is classified as controlled waste under the EPA 1990.

9.2 Japanese Knotweed

Rhizomes extend 3 m deep and 7 m laterally. Key features: hollow bamboo-like stems with red-purple flecks, large heart-shaped leaves with flat base, zig-zag stem growth. Do not disturb without a management plan. Decontaminate all equipment that contacts knotweed material before leaving site.

9.3 Giant Hogweed

Sap is phototoxic — causes severe burns on sunlight exposure. Full PPE (waterproof coveralls, gloves, goggles) required. Isolate the area and notify the supervising ecologist before any works proceed nearby.

9.4 Himalayan Balsam and Biosecurity on Site

Annual plant with explosive seed pods. Cut before seeding; do not allow cut material into watercourses. Before plant or vehicles leave site: pressure-wash all tyres, tracks, and equipment; ensure INNS waste is segregated to designated contaminated waste bays.

9.5 Further Guidance and Training

Invasive Non-Native Species (INNS) are regulated under the Wildlife and Countryside Act 1981 (Schedule 9) and the Wildlife and Natural Environment (Scotland) Act 2011. It is an offence to plant or cause to grow any Schedule 9 species in the wild. Soil, water, or plant material contaminated with INNS must be treated as controlled waste and disposed of by a registered waste carrier.

The GB Non-Native Species Secretariat (NNSS) is the authoritative source for identification guidance, risk assessments, and management protocols for invasive species in Great Britain. The NNSS information portal provides species fact sheets, alert systems, and reporting mechanisms and should be the first reference point when an unfamiliar or potentially invasive species is encountered on site.

Practitioners should ensure they can reliably identify the most commonly encountered INNS on development sites, including Japanese Knotweed, Himalayan Balsam, Giant Hogweed, and Rhododendron. CIEEM and the NNSS publish identification guidance and run training events relevant to INNS management.

10. Hazel Dormice

Hazel Dormouse (Muscardinus avellanarius): nest structure, hazel nut chewing technique identification, and typical habitat. Illustration: Eco Routes.

10.1 Legal Status

European Protected Species under the Habitats Regulations 2017 and Schedule 5 WCA 1981. Surveys and handling require a Dormouse Mitigation Licence (DML). The ECoW must not handle, disturb, or examine nest tubes without the licence holder present.

10.2 Ecology and Survey Methodology

Arboreal, nocturnal rodents of woodland shrub layer and well-connected hedgerows. Minimum 50 nest tubes per survey area, checked monthly April to November. Minimum six checks for a high thoroughness score. Hibernation: October–November through March–April. Characteristic feeding sign: hazelnut shells with smooth circular holes and oblique tooth marks.

10.3 Constraints and During Works

Vegetation clearance of confirmed habitat must be under a DML. If a dormouse is found during clearance: stop immediately; do not handle; contact the supervising ecologist. A dormouse in winter torpor may appear dead — it is not. Do not warm it artificially.

10.5 Post-Clearance Connectivity and Habitat Retention

Hazel Dormice are acutely sensitive to breaks in connectivity. A gap of as little as 10 metres in hedgerow or scrub cover can prevent dormouse movement between habitat patches, and fragmented populations face significantly elevated local extinction risk. The ECoW must ensure that connectivity obligations set out in the CEMP or DML are enforced throughout the construction programme, not only during active clearance.

No continuous hedgerow length may be removed in a single operation. Where the works programme requires multiple separate hedge sections to be cleared, they must be sequenced to retain functional crossing points between them at all times during the clearance period. The CEMP or DML will specify the minimum retention requirements; these are conditions, not guidance.

Replacement habitat — typically hazel, honeysuckle, bramble, and dog rose in a woodland-edge or hedgerow profile — must be planted to the schedule agreed in the DML or CEMP. The ECoW must record the planting date, species, and condition of planted stock. Any transplants that fail within the first growing season must be replaced; flag failures to the supervising ecologist rather than waiting for a post-works inspection. Nest tubes retained within post-works habitat must be maintained and checked under any post-construction licence conditions.

10.4 Clearance Protocol Under a Dormouse Mitigation Licence (DML)

Vegetation removal within confirmed dormouse habitat must follow the compartmentalised programme set out in the DML. Work one compartment at a time: do not open an adjacent compartment until nest tubes in the current compartment have been checked on the day of clearance and the supervising ecologist has confirmed that the compartment is clear to proceed.

Clearance should begin with hand tools — scything, cutting to stump — before any machine follow-through. This allows animals time to move ahead of disturbance. Brush, brash, and log piles cut during thinning must be left undisturbed for a minimum of 48 hours before being moved or chipped; freshly cut material becomes an immediate refuge. Do not chip or burn cut material on the same day as clearance.

If a dormouse, nest, or characteristically disturbed nest tube (suggesting recent occupation) is found: halt all works in that compartment; do not touch or handle the animal or nest; contact the supervising licence holder immediately. The ECoW's role is to enforce the stop and secure the area, not to resolve the situation. Work cannot resume in that compartment without explicit instruction from the licence holder.

10.6 Further Guidance and Training

Hazel Dormice are a European Protected Species listed under the Conservation of Habitats and Species Regulations 2017 and Schedule 5 of the Wildlife and Countryside Act 1981. Any survey, handling, or nest-box checking programme must be conducted by a Natural England licence-holder or under direct licence-holder supervision.

The People's Trust for Endangered Species (PTES) leads dormouse conservation in the UK and coordinates the National Dormouse Monitoring Programme (NDMP). The PTES dormouse guidance and resources are the primary reference for survey protocols, box designs, and seasonal handling schedules. Practitioners should consult PTES materials before commencing any dormouse monitoring programme.

The Mammal Society publishes additional survey and identification guidance relevant to small mammal ecology. Training in dormouse handling and licence-compliant survey methodology is delivered through PTES-accredited courses; details are available on the PTES website.

11. Water Voles

11.1 Legal Status

Schedule 5 WCA 1981. Not an EPS. Maximum penalty: 5,000 and/or six months' imprisonment per animal. No development EPS licence equivalent — mitigation must be secured through the planning system or a WCA licence.

11.2 Field Signs

Water Vole (Arvicola amphibius): riverbank burrow, latrine, feeding station, bank angle, and characteristic blunt-cut grass stems. Illustration: Eco Routes.

Burrows: oval entrances 5–8 cm wide at or just above the water line, sometimes with a grazed lawn. Droppings: 8–10 mm long, blunt-ended, odourless, with a faint greenish tint when fresh; found in latrines near burrow entrances. Feeding stations: 45-degree cuts to grass stems at 8–10 cm lengths in a neat pile near water. Runways: worn paths through bankside vegetation at water level.

11.3 Constraints, Survey Timing, and During Works

Survey: April to October, minimum two visits. Constraints: 5-metre no-work buffer from top of bank where water voles are confirmed or suspected. Bank works timed for August–September. Translocation requires a licensed ecologist. ECoW must not handle water voles.

If water vole or fresh signs found during works: stop immediately; mark the location; contact the supervising ecologist.

11.5 Post-Works Recolonisation Survey

Following completion of bankside or in-channel works and reinstatement of riparian habitat, a post-works survey is required to assess whether water voles have recolonised the working area. This survey is carried out by the supervising ecologist, typically no earlier than one full survey season (April to October) after the completion of bankside reinstatement.

Before the post-works survey takes place, the ECoW must confirm that the reinstated bank profile, substrate, and vegetation match the specification set out in the mitigation plan. Common reinstatement failures that affect recolonisation success include: bank faces graded too steeply (water voles require a gentle slope below the burrow entrance); insufficient emergent and marginal vegetation; compaction of reinstated bank material; and failure of planted reed, sedge, or rush within the buffer zone.

Flag any reinstatement deficiencies to the supervising ecologist and the contractor as a compliance issue, not a snagging item. Correcting a failed bank profile after a post-works survey has returned negative results is significantly more difficult than addressing it during the defects period. The ECoW record of reinstatement condition provides the baseline against which survey results will be interpreted.

11.4 Displacement and Exclusion Protocol

Water vole displacement is a structured, sequential process that must be carried out by a licensed ecologist. The ECoW's role is to enforce the buffer zone, prevent early or unsupervised encroachment into riparian habitat, and monitor for signs of recolonisation or failed displacement.

Displacement typically proceeds in two stages. First, habitat manipulation : progressive reduction of bankside cover over several weeks to encourage voles to move away from the construction zone. This phase must be completed before any hard works — sheet piling, bank grading, culverting — begin within the buffer zone. The ECoW must not permit plant or hand works within the 5-metre buffer zone until the supervising ecologist has formally confirmed in writing that habitat manipulation is complete and displacement survey results support the conclusion that voles have vacated the zone.

Where a culvert or temporary cofferdam is being installed within a confirmed water vole population area, swim-throughs — short sections of the culvert left unblocked at bankside level — must be incorporated in the design to maintain movement. Check that swim-throughs are correctly positioned and unobstructed before any blockwork begins. At watercourse crossings, maintain access along at least one bank throughout the works.

11.6 Further Guidance and Training

Water Voles are protected under Schedule 5 of the Wildlife and Countryside Act 1981 (as amended), making it an offence to intentionally kill, injure, or disturb water voles or damage, destroy, or obstruct access to their places of shelter. Any work within a water vole survey area must follow the mitigation strategy set out in the ecological appraisal.

Natural England's Water Vole: Advice for Making Planning Decisions is the statutory guidance for surveyors and planning authorities and sets out survey requirements, mitigation hierarchy, and licensing obligations. PTES runs the National Water Vole Monitoring Programme and provides habitat management and survey guidance. The Mammal Society also publishes relevant survey protocols and species identification resources.

Practitioners undertaking water vole surveys or mitigation without prior experience should seek formal training from PTES or CIEEM before undertaking unsupervised work.

12. Otters

12.1 Legal Status

European Protected Species under the Habitats Regulations 2017 (Annex II and IV) and Schedule 5 WCA 1981. Offences: deliberate killing/injury/taking; deliberate disturbance; damage/destruction of resting or breeding site. EPS licence required to close or destroy a holt in connection with development.

12.2 Field Signs

Eurasian Otter (Lutra lutra): spraint, couch, holt, tracks, and single pawprint compared with mink and badger. Illustration: Eco Routes.

Spraint: crumbly, fishy-sweet smell (resembles jasmine tea), packed with fish scales and bones, deposited in prominent positions near water (bridges, boulders, confluences). Anal jelly (white, black, or orange) often alongside. Footprints: 5 toes, webbed, approximately 75 mm across — compare with mink (25 mm, unwebbed) and badger (prominent elongated claw marks). Mink scat is thick, gooey, and strongly pungent — distinct from crumbly otter spraint.

Other signs: slides (worn runs entering water); couches (surface scrapes in reedbeds); fish remains (head left on bank, flesh peeled from gills); brown staining of vegetation at repeated spraint sites. Do not handle spraint or prints — use foil or a twig.

12.3 Constraints on Works

No vegetation clearance within 30 metres of any watercourse without ecological sign-off. Do not remove fallen trees within 50 m of a watercourse. Stack timber at least 50 m from the watercourse and remove within 1–2 months.

Confirmed active (non-breeding) holts: no tracked vehicles within 20 m, no hand-digging or scrub clearance within 15 m except under licence.

Confirmed breeding holts: 150-metre exclusion zone. No works of any kind until the female and cubs have self-vacated.

12.4 Holt Inactivity Monitoring and Watercourse Crossings

Before soft-blocking a holt: five consecutive days of stick/sand-pad monitoring with no signs of activity. Active breeding holts must never be blocked.

Watercourse crossings on otter-used rivers must provide a dry ledge at least 500 mm wide, 150 mm above the 1-in-5-year flood level, with 600 mm minimum headroom. Box culverts are preferred over circular pipes. Mammal-deflection fencing (minimum 25–50 m either side) directs otters to the crossing.

12.5 During Works

If an otter is found or fresh spraint is discovered in the work area: stop; do not approach; mark the location; contact the supervising ecologist. Survey results can be superseded by recolonisation — treat unexpected signs as a stop-works trigger.

12.6 Further Guidance and Training

Otters are a European Protected Species listed under the Conservation of Habitats and Species Regulations 2017 and Schedule 5 of the Wildlife and Countryside Act 1981 (as amended). Any works affecting an active otter holt or regular otter habitat require a valid Natural England mitigation licence.

The Mammal Society and PTES are the principal governing bodies for otter survey guidance in the UK. Natural England's Mammal Guidance pages provide statutory direction on survey requirements and mitigation licensing. Practitioners should also consult the Natural England standing advice for otters when assessing likely significant effects on this species.

Formal training in otter survey methodology and sign identification is available through CIEEM and the Mammal Society. Practitioners who regularly work in riparian or wetland habitats should ensure they are competent in identifying otter signs and understand the stop-works requirements applicable to this species.

13. Trees and Ancient Woodland

13.1 Tree Preservation Orders (TPOs)

A TPO protects specific trees or groups of trees in the interest of amenity. It is an offence to cut down, uproot, top, lop, or carry out any works to a protected tree without written LPA consent, unless the tree is dead, dying, or an immediate danger. Penalty: unlimited fine. Trees in Conservation Areas have equivalent protection; six weeks' notice must be given to the LPA before any works.

Before any tree works or vegetation clearance, check the LPA's TPO register. Do not rely on the absence of a physical marker — TPO status must be confirmed through the register.

13.2 Root Protection Areas and Construction Exclusion

The Root Protection Area (RPA) under BS 5837:2012 is a circle with radius of 12 times the trunk diameter at breast height (minimum 1 m radius). For veteran trees, the RPA is the greater of 15 times the trunk diameter or 5 m beyond the canopy edge. No soil compaction, excavation, trenching, materials storage, or vehicle parking within any retained tree's RPA. Tree Protection Fencing must be in place before any ground-disturbing works begin.

13.3 Ancient Woodland

Ancient woodland (continuously wooded since at least 1600 AD) is irreplaceable. Under NPPF paragraph 175, loss or deterioration should be refused except where the need is wholly exceptional. The accepted compensation ratio is 30 hectares of new woodland per hectare of ancient woodland lost. Any loss, however small, is treated seriously.

Minimum 50-metre buffer from the woodland edge throughout construction (100 m for significant engineering). Indirect impacts to prevent: soil compaction within the buffer; chemical, nutrient, or sediment run-off; hydrological changes (SuDS must not be sited within the buffer); INNS introduction; light and noise pollution at the woodland edge.

The Ancient Woodland Inventory (AWI) does not cover woods below 2 ha. Absence from the AWI does not confirm non-ancient status — if any doubt exists, a field survey and historical map assessment should be completed before works begin.

13.4 Ash Dieback

Caused by Hymenoscyphus fraxineus — no cure. Identification: wilting shoot tips; diamond-shaped bark lesions at the base of dead shoots; blackened, shrivelled petioles (leaf stalks); and basal lesions at the root collar. Secondary pathogens (honey fungus, bracket fungi) compromise structural integrity — assume infected ash is more brittle than its crown suggests.

Movement of ash planting stock is prohibited (UK Plant Health Order). Apply biosecurity measures between sites. For felling works on infected trees: use heavier holding cuts and thicker hinge fibres; prefer machinery over manual felling where terrain allows. Do not automatically fell all infected ash — the presumption is against felling living ash unless for public safety or specified management reasons.

13.5 Veteran Trees and the Ancient Tree Inventory

Veteran trees are defined not by age alone but by structural and ecological characteristics: deeply furrowed or decoupled bark, standing deadwood, crown retrenchment, cavities (natural hollows, woodpecker holes, rot pockets), bracket fungi, epiphytic moss and lichen communities, and significant ivy cover. These features provide irreplaceable habitat for bats, specialist invertebrates, and fungi that may have taken centuries to develop and cannot be recreated on a planning timescale.

Before any works near a tree identified as veteran, ancient, or of notable size, check the Woodland Trust Ancient Tree Inventory (ATI) and the MAGIC mapping portal for recorded features and statutory designations. Veteran trees outside Ancient Woodland may still qualify for TPO protection or constitute a material planning consideration under NPPF. Refer the arboricultural report and any ATI record to the LPA arboricultural officer before works commence within the RPA.

No ivy removal, dead branch clearance, or cavity management on veteran trees without explicit written approval from the supervising ecologist and, where a bat roost function is likely, a licensed bat ecologist. Ivy and deadwood are not nuisances on veteran trees — they are the primary features for which the tree has ecological value. The Ancient Tree Forum Guide 5: Trees and Development sets out the assessment framework and should be consulted when any identified veteran tree is within the construction envelope, access route, or its extended RPA. For trees on or adjacent to Ancient Woodland, refer additionally to Natural England's standing advice for ancient woodland and veteran trees.

13.6 Further Guidance and Training

Ancient, veteran, and notable trees are material considerations in planning decisions under the National Planning Policy Framework (NPPF) and are subject to protections including Tree Preservation Orders (TPOs) and, where located in or adjacent to Ancient Woodland, the Natural England Ancient Woodland and Veteran Trees standing advice.

The Woodland Trust and the Ancient Tree Forum (ATF) are the primary governing bodies for ancient and veteran tree conservation in the UK. The ATF's Trees and Development guidance and the MAGIC mapping portal (which shows statutory designated sites and Ancient Woodland Inventory data) are essential references for practitioners working near trees and woodland. The Ancient Tree Inventory, maintained by the Woodland Trust, should be checked when working in areas likely to support veteran or ancient trees.

The Arboricultural Association sets professional standards for tree survey and protection work, including BS 5837:2012 (Trees in relation to design, demolition and construction). Practitioners undertaking tree protection inspections should be familiar with this standard. CIEEM offers CPD training relevant to ecological assessment of trees and woodland habitats.

Glossary

Adder (Vipera berus) The only venomous snake native to the UK. Protected under the WCA 1981. Must not be handled by the ECoW.

Agrichlor A chlorine-based disinfectant (NaDCC) used for survey equipment biosecurity. H400/H410 — very toxic to aquatic life. Never apply near open water.

Ancient Woodland Land continuously wooded since at least 1600 AD. Includes ASNW and PAWS. Irreplaceable habitat under the NPPF.

AWI Ancient Woodland Inventory. Does not cover woods below 2 ha. Absence from the AWI does not confirm non-ancient status.

BCT Bat Conservation Trust. National helpline: 0345 1300 228.

BNG Biodiversity Net Gain. Mandatory under the Environment Act 2021 for most development in England to deliver a minimum 10% increase above the pre-development biodiversity baseline.

BRA Bat Roost Assessment. A tiered survey process to establish bat presence or absence in a building or tree. Carried out by licensed ecologists.

CEMP Construction Environmental Management Plan. The document setting out how environmental impacts will be managed during construction. The ECoW works to the CEMP.

Check-Clean-Dry Biosecurity protocol for survey equipment. Prevents spread of aquatic diseases and invasive species between sites.

Couch A surface resting scrape used by otters in reedbeds or dense bankside vegetation, as distinct from a holt (underground shelter).

DLL (District Level Licensing) A strategic GCN licensing scheme enabling developers in participating districts to contribute to a conservation fund rather than undertaking site-level EPS licensing.

DML (Dormouse Mitigation Licence) A Natural England licence enabling a licensed ecologist to handle, disturb, and translocate dormice.

DRA Dynamic Risk Assessment. An in-the-field assessment of hazards and controls completed before starting work on a new land parcel or in changed conditions.

ECoW Ecological Clerk of Works. The ecologist responsible for on-site ecological compliance during construction or clearance works.

EPS European Protected Species. Listed under the Habitats Regulations 2017. Includes bats, GCN, otters, dormice, sand lizard, and smooth snake.

GCN Great Crested Newt (Triturus cristatus). EPS. Requires licences for development affecting ponds within 500 m or terrestrial habitat within 250 m.

Habitats Regulations The Conservation of Habitats and Species Regulations 2017 (as amended). Primary UK EPS legislation.

Hazel Dormouse Muscardinus avellanarius. EPS dependent on well-structured shrub-layer woodland and hedgerow. Nocturnal and arboreal. Surveyed using nest tubes.

Holt An otter underground or in-bank resting shelter, typically under tree roots or in a steep bank. Protected whether or not otters are present.

HSI Habitat Suitability Index. Scoring system to assess the suitability of a pond for GCN.

INNS Invasive Non-Native Species. Controlled under Schedule 9 WCA 1981. Commonly encountered: Japanese Knotweed, Himalayan Balsam, Giant Hogweed, Rhododendron.

Japanese Knotweed Fallopia japonica. Highly invasive Schedule 9 plant. Soil containing knotweed is classified as controlled waste under the EPA 1990.

Latrines Territorial dung deposits. In badgers: dug pits at territory boundaries. In water voles: accumulations of droppings at prominent bank features.

NE Natural England. Statutory nature conservation body for England. Issues EPS licences and enforces wildlife law.

PAWS Plantation on Ancient Woodland Site. Ancient woodland where original tree cover has been replaced by planted species. Retains irreplaceable ancient woodland soil characteristics.

PBA 1992 Protection of Badgers Act 1992. Primary legislation protecting badgers and their setts.

Pitfall Trap Container sunk into the ground at a drift fence to capture amphibians and reptiles for survey. Must be checked every morning to prevent mortality.

RAMS Risk Assessment and Method Statement. Required before ecological fieldwork and construction-phase supervision.

Refugia (AR) Artificial Refugia. Squares of roofing felt or corrugated tin placed on the ground to attract reptiles for survey.

RPA Root Protection Area. Ground area around a tree within which soil disturbance must be avoided. Calculated under BS 5837:2012 as 12x trunk diameter (minimum 1 m radius); for veteran trees, 15x trunk diameter or 5 m beyond the canopy.

Schedule 1 Bird Bird listed on Schedule 1 WCA 1981. Intentional or reckless disturbance at or near an active nest is an offence.

Schedule 5 Schedule 5 WCA 1981. Animals fully protected against taking, disturbance, and habitat damage in addition to killing and injury.

Sett A badger underground shelter. Protected under the PBA 1992 whether or not badgers are present.

SNCB Statutory Nature Conservation Body: Natural England (England), NatureScot (Scotland), Natural Resources Wales (Wales).

Spraint Otter faeces used as a territorial marker. Crumbly, packed with fish scales and bones, with a fishy-sweet smell. Deposited in prominent positions near water.

Survey Validity Period The period for which a survey result is considered current and reliable. For most species: two to five years. Surveys must be updated if works have not commenced before validity expires.

Thoroughness Score A metric applied to dormouse nest tube surveys. A low score means a negative result may not be reliable — additional survey effort may be required.

TPO Tree Preservation Order. LPA order protecting specific trees or woodland. Unlimited fine for unauthorised works.

Trench Ramp A slope of soil, sand, or timber in any open excavation left overnight, enabling small mammals and amphibians to escape. Required wherever open trenches are present.

Virkon Aquatic Peroxygen-based disinfectant for equipment biosecurity. 1% solution (one 5 g tablet in 500 ml). Discard when pink colour fades or after 7 days. H400/H410 — never allow to enter watercourses.

WCA 1981 Wildlife and Countryside Act 1981 (as amended). Primary domestic wildlife protection legislation.

Water Vole Arvicola amphibius. Schedule 5 species of slow-flowing or still watercourses. Significant UK population decline due to habitat loss and mink predation.

WSI Written Scheme of Investigation. An LPA-approved document setting out the methodology for archaeological evaluation or mitigation. The governing document for trial trenching programmes.