Gathering the Evidence Base

Statutory Duty

All plan-making authorities have a statutory duty to keep under review the evidence (which includes information about the natural environment) necessary to prepare and review their plans.

In addition to making sure that all relevant nature conservation resources are mapped on proposals maps, there is a need to adequately understand the implications of the plan, both positive and negative, for the biodiversity resource. The SEA / Sustainability and Habitats Regulations Appraisal processes will help in this task, by applying systematic and rigorous assessment techniques to all aspects of the plan that could affect the natural environment.

Focus on the key issues you have developed and ensure that the plan is adequately informed about them. This may involve collating and mapping information about areas that could be enhanced and areas that need protection from the proposals in the plan.

There is a considerable amount of information already available, it is likely to be more than you need, but occasionally the consideration of particular plan proposals may need to use information not readily available.

The evidence base should be focused on what will be needed to provide the information that will be used to write and formulate the vision, identify and address the issues, set the objectives, deliver them through policies and proposals and monitor their effectiveness.

Take a proportionate approach and don’t start from scratch.

Think about how the evidence base used in the previous / current version of your plan could be improved and updated.


Useful Checklists and Support

A useful ‘checklist’ for what your evidence base should contain, relevant to any plan in the UK, can be found on page 4 of the Good Practice Guide for the English PPS 9.

Also consider looking at the CLG Planning Advisory Service Evidence Base Support 

And the evidence base part of the Plan Making Manual  


Sources of Information

In addition to links provided elsewhere in this part of the toolkit, key sources of information are:

England  Natural England's digital boundary datasets and xml files for all designated sites 

Scotland  Scottish Natural Heritage’s information web

This has an up to date interactive database including: site based information, trends and indicators, facts and figures and a GIS interface.

Wales  Countryside Council for Wales’s protected sites and landscapes map and GIS boundary downloads


Local Environmental Record Centres

And in all cases your local environmental records centre should be used as a critical source of well informed advice and information of particular value because of its local knowledge base.

Consider what is needed to suit the type, scale and level of detail in the plan.

Obtain the advice of ecologists and others with knowledge of the area as to what information they think you need to know and what is available. But they may be over-enthusiastic so be careful not to gather too much detailed information unnecessary for the plan!


Landscape Scale and the Big Picture 

For plans covering larger areas, think about ‘the big picture’ - how the plan area varies in terms of its ‘bio-geographic’ character, this is about how wildlife habitats and species may differ across the area according to elevation, topography, landscape, geology and natural processes, such as river systems and coastal processes, all of which influence the distribution of wildlife and natural features.

The following resources can help in this process:

Natural England’s National Character Areas

Scottish Natural Heritage’s Natural Heritage Futures

Countryside Council for Wales’s LANDMAP

Landscape Character Assessments can also help in this process where they are available.


Designated Sites

Ensure that the location and extent of internationally, nationally and locally designated sites are mapped for the plan area and ensure that the ways in which the plan’s proposals could affect designated sites are adequately understood. Take advice if the potential effects are uncertain. This information will be essential for the SEA and HRA processes.

Concentrate information gathering on areas where the plan is likely to direct or concentrate change, try to avoid gathering information simply because it is available, or if it is unlikely to be used.


Species and Habitats of Importance for Biodiversity Conservation

Consult records about the presence and distribution of habitats and species listed by the Government as of special importance for biodiversity conservation, especially where the plan may encourage change which may adversely affect or create positive opportunities for biodiversity conservation.  

Find out more >>  List of Species of Principal Importance in England

Find out more >>  Priority Species for Northern Ireland

Find out more >>  Scottish Biodiversity List

Find out more >>  List of Species of Principal Importance for Wales


Local Biodiversity Action Plans

Local Biodiversity Action Plans will concentrate on habitats and species of particular importance locally. These may refer to the importance of ancient or semi-natural woodlands and veteran trees.

Ensure you take account of:

  • the information provided by and the policies and targets in Regional and Local Biodiversity Action Plans:
  • the biodiversity value of previously developed land including derelict, underused or contaminated land: and
  • opportunities for enhancement created by changes that the plan may be encouraging.