Ecology advisory service

• Desktop ecological assessments and data searches
• Time planning around seasonal constraints
• Various types of ecological surveys, including Preliminary Ecological Appraisal (PEA) and Phase 1 and 2 surveys
• When an Environmental Impact Assessment (EIA) is required
• Mitigation and enhancement opportunities
• Pre-application and early-stage planning advice

To provide us with the information we need, it is likely you will need to submit an ecological report with your application if any of the following conditions apply:

• your application meets certain criteria in the local planning authority's (LPA) biodiversity checklist
• there's a risk of the proposed development affecting protected species such as bats or great crested newts
• your local planning authority has been advised by LEADS Ecology, or other informed consultees, that there is a risk of the proposed development harming biodiversity.

This section deals with applications that are limited to the demolition of, or modifications to, the property itself. 

For guidance on those applications that seek to increase the footprint of a property, either by means of extension to the property or the creation of a new structure separate from the property such as a separate garage, shed or summerhouse, see ‘Applications that increase the footprint of the property' below.

Houses of all styles, whether old or new, can support roosting bats and/or breeding birds. Though you may not be aware of them, birds can nest in lofts, gutters or gaps in the brickwork and bats can roost or shelter in the loft, beneath tiles and in the tiniest of gaps elsewhere. All are protected, most are in decline and all are especially vulnerable to householder applications for demolition, loft conversions and extensions amongst others. Indeed, although levels of protection vary, in general terms, as all bats and breeding birds, and their roosts and their nests are protected in law, it could be a criminal offence were you to harm these species.

The best way to find out if there is a reasonable risk of supporting bats is to complete your local authority’s ‘biodiversity checklist’. We strongly encourage all householders to add photographs of the property when submitting the checklist. See 'Can I submit photographs instead of commissioning a survey?' below. On receipt of this information your planning department and LEADS Ecology will determine the level of risk.

If the risk is low, there will be no need for bats to be considered further.  Where there is a risk, LEADS Ecology may recommend that a survey (or Preliminary Roost Assessment) is undertaken to check if there is any evidence that a roost may be present.  The reason for this is to make sure potential impacts are understood and allow measures to be adopted to reduce the risk of harm and of inadvertently committing an offence, and to enhance the value of the property for biodiversity. Such surveys can only be carried out by professional ecologists.

If the Preliminary Roost Assessment (PRA) finds the presence of a roost is unlikely, there is no reason for bats to be considered further. However, if a bat roost is found or there is reasonable potential for one to be present, up to three further ‘activity’ surveys at dusk may be required.

Whilst a PRA can be carried out at any time of the year, activity surveys can usually only be carried out when bats are active, typically between May and August, or September if the weather remains fine. Occasionally, if a winter hibernation roost is found or suspected, we may request a winter survey. Householders should bear in mind these potentially important seasonal constraints when planning their development.

If a bat roost is confirmed, mitigation measures will be required though most are relatively straightforward and typically include the careful destruction of the roost, and the installation of bat boxes to provide an alternative roost elsewhere in the roof, loft or walls of the property though occasionally it can be more complex.

In contrast, we rarely ask for breeding bird surveys, although a good Preliminary Roost Assessment should always identify if breeding birds are present though mitigation measures are usually more straightforward and typically comprise replacement nest boxes on, or around the property. This provides an opportunity to enhance biodiversity on your property by adding more boxes than necessary. 

Importantly, although many household improvements benefit from permitted development rights, this does not remove the need to take full account of potential impacts on biodiversity.

Bat surveys – further guidance on what to expect

Further guidance on what to expect from a bat survey can be found at the Bat Conservation Trust.

If a survey or report is needed, we strongly advise that you find a consultant by using the CIEEM directory.  Importantly, you should make sure they hold the appropriate licences from Natural England that allows them to both carry out surveys and undertake mitigation activities on bats and roosts. 

The Bat Conservation Trust provides further advice about finding an ecological consultant.

This section deals with applications that increase the footprint of a property, either by means of extension to the property or the creation of a new structure separate from the property including conservatories, garages, sheds and summerhouses. Those applications that do not propose an increase to the footprint of the property should refer to 'Applications that do not increase the footprint of a property‘ above.

Householder applications that increase the footprint of a property can involve the loss of all or part of an existing garden. Gardens can play an important role in supporting not only highly protected species such as badgers, bats, great crested newts and breeding birds but also more widespread species such as hedgehogs, frogs, toads and reptiles. The protection of all of these is important if we are to halt the decline in biodiversity across our county. Although levels of protection vary, it could be a criminal offence were you to harm bats, great crested newts, badgers or breeding birds amongst others.

Whilst in most cases LEADS Ecology will not recommend ecological surveys for gardens, there are some exceptions as follows:

• where there are records of the presence of protected species such as badgers, great crested newts or reptiles such as slow worms within the garden or nearby
• where trees are being removed that might provide roosts for bats.• Where the garden is part of a Local Wildlife Site
• where the garden includes areas of ponds and orchards. 

The best way to find out if there is a reasonable risk of your garden supporting biodiversity is to complete your local authority’s ‘biodiversity checklist’.  We strongly encourage all householders to add photographs of the property when submitting the checklist. See ‘Can I submit photographs instead of commissioning a survey’ below. On receipt of this information your planning department and LEADS Ecology will determine the level of risk.

If we find the risk is low, there is no reason for the ecological impact of your proposal to be considered further.  If, on the other hand, the risk is high, LEADS Ecology may recommend that an appropriate survey is carried out or, for more substantial proposals, that a Preliminary Ecological Assessment is completed. These can only be carried out by professional ecologists.

The reason for this is to make sure potential impacts are understood and allow measures to be adopted to reduce the risk of harm and of inadvertently committing an offence, and to enhance the value of the property for wildlife. This will ensure your local planning authority has all the information on biodiversity it needs to make its decision.If important species or habitats are found, mitigation measures will be required though most are relatively straightforward and typically comprise making sure the work is carried out carefully though occasionally it can be more complex.

This usually arises where there is a reasonable risk bats, badgers or great crested newts might be present.  Where this occurs, it is likely, but not inevitable, that we will recommend that suitable surveys are carried out and the production of a report which will describe the mitigation required and any possible enhancements that could be delivered.

Importantly, although many household improvements benefit from permitted development rights, this does not remove the need to take full account of potential impacts on biodiversity.

Further guidance

If a survey or report is needed, it's important to choose an experienced ecologist to carry out ecology surveys and reports. They should have the right knowledge and licenses to both carry out surveys and undertake mitigation activities on great crested newts. You can find a list of trusted ecologist practices and consultants on the Chartered Institute of Ecology and Environmental Management (CIEEM) website.

Photographs cannot substitute for an ecological survey. However, they can help LEADS Ecology make a more informed ecological judgement as to the need for a survey. Therefore, we strongly encourage these are included with all householder applications.

Guidelines are included below as to the type of photographs that are most useful. If photographs are submitted, LEADS Ecology may still advise your local planning authority that an ecological survey is still required. 

Photographs are particularly useful for deciding if bats could be at risk. Therefore, if it is safe to do so, please provide photographs of the following (all photographs can be taken from ground level):

• gable end edges, sufficient to reflect their overall nature and condition
• bargeboards, fascias and soffits
• external roof and tiles
• internal loft spaces if accessible – to include roof lining, ridge, beams and floor / insulation.

If a garden (including a pond) is affected, please provide photographs of the entire area that will be affected. Without photographs it is more likely that a professional survey will be required in order to determine the presence of protected species which may be affected. 

We will advise the LPAs that:

• where applications have been submitted prior to the start date of mandatory net gain, we will advise that the BNG metric used should be either the most up to date version available at the time of application or if the applicant is seeking to demonstrate that it is compliant with current NE advise the statutory metric
• in all other cases the Statutory metric should be used.

In all cases we will advise that:

• the full original metric spreadsheet should be provided. A summary, pdf version or screenshot on its own is insufficient
• the information required on the start page should be completed in full. 

Following the publication of the Local Nature Recovery Strategy (LNRS), Strategic Significance should be set using the LNRS. See Advice on the Local Nature Recovery Strategy.

Metric Supporting information

Biodiversity Opportunities and Local Wildlife Sites

• Restore Liquorice Piercer Moth populations
• Restore Mottled Grasshopper populations
• Restore Crested Cow-wheat populations through management and creation of woodland habitat etc. 
• Restore Crucian Carp populations
• Restore Scarce Tufted-sedge populations
• Restore Turtle Dove populations
• Restore Black-poplar populations.

• Manage the impacts of deer and Grey Squirrel to acceptable levels to allow natural regeneration and structural diversity within existing and new woodland, and reduce the impact on biodiversity, the rural economy and losses of carbon stores (see Action 3 for Lowland Broadleaved Woodland and Scrub)
• Improve the quality of water that flows into stream sinks to reduce the load of contaminants entering aquifers (see Action 8 for Rivers, Chalk Streams and Floodplains)
• All canals / navigations should be managed to balance their function as commercial/recreational waterways with their ecological function (see Action 9 for Rivers, Chalk Streams and Floodplains)
• Eradicate and slow the spread of invasive non-native species (INNS) in our rivers, navigations, canals and wetlands through taking a catchment-based approach (see Action 10 for ‘Rivers, Chalk Streams and Floodplains)
• Create natural reedbeds along river corridors, in river valleys (see Action 2 for Fens and Reedbeds)
• Create new areas of fen habitat where conditions allow (see Action 4 for Fens and Reedbeds).

• Manage the farmed landscape to safeguard and enhance the water environment (see Action 1 for Farmland)
• Restore soil health and habitat for soil micro-organisms and decomposers (see Action 2 for Farmland)
• Create more habitat for farmland birds (see Action 3 for Farmland)
• Improve habitats to support wild pollinators (see Action 4 for Farmland)
• Improve connectivity by expanding and linking up areas of existing wildlife rich habitats (see Action 5 for Farmland)
• Halt and reverse fragmentation of habitat in the built environment to better connect urban areas to rural areas (see Action 1 for Urban) 
• Enhance public green and blue spaces that provide a home for nature (see Action 2 for Urban) 
• Enhance and maintain habitat for lichens, mosses and fungi (see Action 3 for Urban)
• Enhance private gardens for nature (see Action 4 for Urban)
• Enhance buildings and infrastructure, making new developments more nature-friendly and improving existing buildings and surfaces (see Action 5 for Urban)
• Enhance allotments for wildlife (see Action 6 for Urban)
• Maintain diverse habitat on brownfield sites (see Action 7 for Urban)
• Enhance urban habitats through utilising nature-based solutions to provide wider environmental benefits (see Action 8 for Urban)
• Improve access to greenspace for those with the lowest levels of access (see Action 9 for Urban).

• Surveys used to populate biodiversity metrics should be designed and carried out so that the UK habitat types present can be directly determined.  This will require use of quadrats. The use of other habitat classification systems that require translation via correspondence tables, other than for historic data sets, should not be used without consultation with the local planning authority.
• To accurately describe UK habitat types a range of different measures such as % cover, abundance and species richness are often required. A simple measure of species richness alone is rarely sufficient. 

Grasslands are very vulnerable to loss by development and over 98% of Hertfordshire semi- natural grasslands have already been lost.  Where they are affected, particular care needs to be taken to correctly identify the grassland type so that suitable mitigation or compensation can be devised.

• Surveys of existing grasslands should be carried out within the optimal survey period of mid-May to mid-August. Any surveys outside this period must be accompanied by compelling reasons as to why this is acceptable.
• Survey area – small areas of similar stands of vegetation should be surveyed with a minimum of five quadrates or three if the area is very small but significant.  In larger homogeneous areas a minimum of ten quadrats should be used to ensure that at least 2% of the total area is surveyed in detail. The methodology should be fully described, and the location of all quadrats should be shown on the habitat map.
• When assessing the grasslands, the information gathered should be sufficient to allow an assessment against the UK habitat descriptions for all grassland types. This should include as a minimum:
  a. Measures of abundance using the DAFOR scale of key grassland species identified in UK Habs, such as rye grass and false oat grass, as well as the overall abundance of grass species associated with intensive agricultural production.
  b. The abundance of indicator species of soil fertility.  
  c. % cover of grass species relative to forbes.  
  d. Overall % cover of key grass and ford species identified in UK Habs', such as rye grass and white clover. 
  e. Number of species per metre square. 
  f. Abundance of indicator species listed within UK habitat descriptions using the DAFOR scale.  
• The absence of elements of this information can result in a lack of confidence in the assessed distinctiveness of the grassland and its base line value measured in the metric. This can result in us advising the LPA that further surveys are required resulting in potentially costly delays.

The England Woodland Biodiversity Group (woodland condition methodology should be used for condition surveys, however, the appropriate statutory condition sheet should be completed for the assessment as this is adapted for use with the statutory metric.