Biodiversity assessment

Last Updated: 23 August 2023

We have to consider the conservation and environmental net gains for biodiversity when deciding a planning application. This includes the protection of protected species, designated sites, habitats and geological features.

When required

A biodiversity assessment (sometimes known as an ecological assessment or nature conservation assessment) will be required for all major applications or greenfield development (usually agricultural or amenity land) that could directly or indirectly impact on rare, protected, or notable species or habitats protected by:

  • the Wildlife and Countryside Act 1981
  • the Conservation (Natural Habitats etc.) Regulations 2010
  • the Conservation of Habitats and Species (Amendment Regulations 2012)
  • the Protection of Badgers Act 1992

A biodiversity survey may include either a protected species survey and/or an ecological or geological survey.

A protected species survey and assessment should be submitted where the development involves:

  • demolition of a building
  • conversion of a building (for example, barn conversion)
  • works to bridges, viaducts, tunnels, mines, kilns, cellars and underground ducts and structures
  • works near watercourses, wetlands and ponds and/or wooded areas
  • buildings known to support roosting bats
  • development affecting the roof space of a building

An ecological survey should be submitted where the development involves:

  • works to trees or hedgerows
  • overgrown sites
  • development within or adjacent to a Site of Special Scientific Interest, Special Protection Area, Ramsar Sites, Special Areas of Conservation, Sites of Biological or Geographical Importance (National Nature Reserve, County Wildlife Site, Regionally Important Geological/Geomorphological Sites (RIGS), Wildlife Trust Reserves)
  • sites involving Ancient Woodland

Some smaller applications (including some householder proposals) that fall into the above designated sites, green gaps, or include proposals that will impact upon overgrown land, may also require an ecological assessment.

Proposals that involve the removal of trees, scrub, hedgerows or alter water courses will need to supply information on species present, potential impacts on those species and the mitigation for such impacts.


The Cumbria Biodiversity Data Centre is a source of evidence that should be used in a biodiversity assessment as there is a desk study enquiry, including species, habitat and sites data service available for developers.

Surveys and reporting will need to be undertaken by appropriately qualified, experienced and licensed ecologists.

Reports and surveys should be carried-out in accordance with nationally recognised guidance during appropriate times/months of the year, in suitable weather conditions and using recognised surveying techniques.

We will not validate an application unless we are confident that full information on the likely ecological impacts of the proposals can be provided within the application timeframe. This allows for flexibility in cases where further ecological surveys are required to determine the presence or absence of a species but due to the seasonality of ecological surveys, the consideration of the application would be unduly delayed.

Arnside and Silverdale Area of Outstanding Natural Beauty

Proposed development in the Arnside and Silverdale Area of Outstanding Natural Beauty (AONB) may need to be accompanied by an ecological survey, including an assessment of the role the application site plays in the local ecological network. The survey and assessment should be proportionate to the scale of the development.


Policy CS8.4 South Lakeland Core Strategy - Biodiversity and Geodiversity

Policy DM4 South Lakeland Development Management Policies Development Plan Document - Green and Blue Infrastructure, Open Space, Trees and Landscaping

Policy AS04 Arnside and Silverdale Area of Outstanding Natural Beauty (AONB) Development Plan Document (DPD) - Natural Environment