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  4. Ecological assessments

Ecological assessments

The Local Planning Authority needs to fully understand all the impacts, both negative and positive, of a proposed development, including the impacts on wildlife and biodiversity. When submitting a planning application, it may be necessary for you to include an ecological assessment (sometimes referred to as a Biodiversity Survey and Report) to provide this information.  

When will a nature conservation or ecological assessment be required?

You should submit an ecological assessment with a planning application when the development proposals (including any associated off-site works) will affect the following:

  • Designated sites 
  • Priority habitats 
  • Other biodiversity features 
  • Species protected by law 
  • Priority species 

If, during the course of pre-application discussions, you have agreed with the council's Biodiversity Officer that an ecological assessment is not required, this should be made clear on the completed validation checklist form.

Designated sites

The designated sites are illustrated in the Local Plan 2011 to 2031 and include:

Priority habitats

These are wildlife habitats that are listed at section 41 of the Natural Environment and Rural Communities Act 2006 as being habitats of principal importance for biodiversity. In West Oxfordshire District this includes:

  • ancient and/or species-rich hedgerows
  • floodplain grazing marsh
  • fen, marsh, swamp and reedbeds
  • lowland beech and yew woodland
  • lowland calcareous grassland (e.g. species-rich chalk and limestone grasslands)
  • lowland meadows (e.g. species-rich flower meadows)
  • lowland mixed deciduous woodland (ancient woodland)
  • lowland wood-pasture and parkland
  • rivers and streams
  • standing open water and canals (e.g. lakes and flooded gravel pits)
  • wet woodland

Other Biodiversity Features

There are other important habitats and features that are not included in the national list of priority habitats, but are of great local importance, these include:

  • secondary woodland
  • mature, ancient or veteran trees
  • caves, mines and disused tunnels
  • trees and scrub (potential bird nesting areas)
  • previously developed land with biodiversity interest
  • urban green space (such as allotments, disused railway lines)
  • ponds

Protected species

There are a number of species that are protected by law, for example under the Wildlife and Countryside Act 1981 as amended and the The Conservation of Habitats and Species Regulations 2010)

For a full list see the government circular 06/2005: biodiversity and geological conservation - statutory obligations and their impact in the planning system.

An ecological (protected species) assessment will be required for development that could affect protected species. 

Priority species

These are species that are listed at section 41 of the Natural Environment and Rural Communities Act 2006 as being species of principal importance for biodiversity.

Bats and lighting

Bats are nocturnal which makes them sensitive to artificial lighting. Inappropriate lighting can increase predation on bats, prevent them from feeding, commuting or getting in and out of their roost.

If bats are present you should get ecological advice and consult a lighting engineer in the early planning stages. More detailed information is available from The Bat Conservation Trust artificial lighting guidance.

The ecologist will need to provide:

  • identification of key habitats / roosts
  • recommended buffer zones and widths
  • species-appropriate lux limits (0 - 1 lux)
  • seasonal or time-based variations
  • requests for vertical, elevated horizontal or upward calculation planes (lux contour plans)

The lighting engineer will need to provide:

  • lux contour plans including those specified by ecologist
  • luminaire and complete lighting specification, number, model, output settings, maintenance factor
  • details of assumptions and conditions for example, duration, timers,
    internal lighting, curtains
  • an explanatory note including potential glare sources and mitigation

Mitigating the effect of development

You can mitigate the effect of development on bats by including dark buffers, illuminance limits, zonation, appropriate luminaires, sensitive site design, screening, glazing treatments, creation of alternative habitats and dimming.

Mitigation options should be recommended by the lighting engineer and the ecologist

Key lighting specifications

Lighting suitable for bats should have:

  • LED
  • warm white spectrum < 2700 Kelvin
  • a dimmable light, with motion sensors (PIR) and short timers
  • 0% upward light ratio
  • careful consideration of position and height
  • recessed internal lights
  • screening (planting, hardscape, hoods or cowls)

What should be included in an ecological assessment

The level of assessment required will vary from a simple biodiversity survey to a complex ecological assessment as part of an Environmental Impact Assessment.

Ecologists carrying out nature conservation/ecological assessments should have the appropriate experience and qualifications.

Any survey or assessment should be carried out at the appropriate time of year, in suitable weather conditions and using nationally recognised survey guidelines/methods. For guidance on appropriate survey methods visit the Institute for Ecology and Environment Management.

It is important that any assessment includes both on and off site impacts. Pipelines and cable runs serving the site which go beyond the site boundary should be assessed because they can cause impacts elsewhere, for example development can lead to changes in hydrology which can affect habitats at some distance away. 

Details of ecological consultants

  • Name and experience of the ecologist who has undertaken the survey

Desk-based study of the site

  • A general description of the site, explaining its location and a map
  • The current status of the site (e.g. is it a designated site?)
  • Any designated sites within 1km should be identified on a plan
  • Presentation and analysis of existing ecological data 
  • Copies of any consultations with statutory or non-governmental organisations, such as Natural England, the Environment Agency or the Wildlife Trust

Field-based study of the site

  • Date, time, temperature and weather conditions at the time of survey.
  • Up-to-date survey information for the site, including survey methods, and results (species and habitats present and their extent, frequency and location - all data collected should be included). The type of survey will depend upon the nature of the site and the likely impact of the proposed development. For more information on survey methodologies visit the Institute for Ecology and Environmental Management

Evaluation of the site

  • Evaluation of the ecological importance of the site
  • Impact of the proposed development on the biodiversity of the site and its surroundings
  • If European protected species are affected, consideration should be given to the 'derogation' tests
  • Mitigation and compensation proposals  (including habitat management, enhancement and creation proposals)
  • Net impacts of the proposed development 

What else should be submitted with an ecological survey?

If mitigation and compensation proposals have been recommended within the ecological assessment, you should illustrate them on your submitted drawings. For example, if a bat loft is recommended within a barn conversion, you should detail the location and the dimensions of the loft in the submitted plans so that the Local Planning Authority can be satisfied that the mitigation measures can be achieved as part of the development.

You should always submit surveys and mitigation proposals as part of the planning application. If you undertake and submit them later in the process, there is a risk that the plans for the development will have to be redesigned or halted (temporarily or permanently) for example if protected species are found on site.