
Net Benefit for Biodiversity
Net benefit for Biodiversity (NBB) has an integral role in sustainable development and is fundamental to the social and economic wellbeing of Carmarthenshire’s residents.
Biodiversity enhancements are the features of a project or a planning application which will secure Net Benefits for Biodiversity (species and or habitats) as result of the proposed project being delivered.
Any planning proposal must demonstrate that it has both maintained and enhanced biodiversity and built resilient ecological networks through green infrastructure. Biodiversity enhancements that achieve NBB must be delivered following implementation of the stepwise approach, or mitigation hierarchy, of firstly avoiding, then minimising, mitigating and as a last resort compensating for, adverse impacts on the environment in a development. A Green Infrastructure Statement should be submitted with all planning applications.
Legislation and planning policy that apply in Wales now require that development must maintain and enhance biodiversity in the exercise of their functions. This means that development should not cause any significant loss of habitats or populations of species, locally or nationally and must provide a Net Benefit for Biodiversity.
The Chief Planning Officer in the Welsh Government has stated that
“Where biodiversity enhancement is not proposed as part of an application, significant weight will be given to its absence, and unless other significant material considerations indicate otherwise it will be necessary to refuse permission.”
(Chief Planner, Planning Directorate, Welsh Government, October 2019).
An ecologist will look at your proposals, they will advise how best to minimise any the impact of the development you propose on biodiversity, and what would be suitable in terms of enhancements.
Relatively small applications, for example extensions, householder applications and single dwelling developments:
An annotated plan should be submitted with your planning application - this should be in the form of a Green Infrastructure Statement which should be submitted with all planning applications - for example laying out areas of tree, hedgerow, shrub and pollinator planting (native plant species are preferred, but other nectar bearing plants can also be used in the garden context provided they are not invasive). An annotated plan of an elevation can show how bat features will be built in. Integrated bat and bird boxes should be used on new buildings as these are long lasting.
Potential applicants should not conduct any pre-emptive site clearance works before submitting a planning application as this can make it more difficult for a development proposal to secure a net benefit for biodiversity. Where a site has been cleared prior to development its biodiversity value should be deemed to have been as it was before any site investigations or clearance took place.
Biodiversity Net Benefit: Householders (Sir Fynwy / Monmouthshire)
These schemes will require professional ecological advice regarding the impact of the development on biodiversity, habitats, and species and how you will be delivering Net Benefit for Biodiversity. A Green Infrastructure Statement, which should be submitted with all planning applications, is a useful way of setting out how you will deliver a net benefit for biodiversity. Make sure that for proposals for Net Benefit for Biodiversity are integrated with any other landscaping and Nature Based SUDS proposals.
Planning authorities must follow a step-wise approach to maintain and enhance biodiversity - adverse effects are firstly avoided, then minimized, mitigated, and as a last resort compensated for – and secure the maintenance and enhancement of ecosystem resilience and resilient ecological networks by improving diversity, extent, condition, and connectivity i.e. the DECCA Framework.
Enhancement must be secured by delivering a biodiversity benefit primarily on site. A scheme of enhancements must be provided to ensure a net benefit for biodiversity. Pre-application surveys, research and data searches by developers will be necessary to establish the baseline state of biodiversity and ecosystem resilience.
The Building with Nature standards represents good practice and are an effective prompt for developers to improve the quality of their schemes and demonstrate the sustainable management of natural resources. The standards are underpinned by an accreditation system and whenever possible, accreditation under these standards should be pursued.
Each stage of the step-wise approach must be accompanied by a long term management plan. The management plan should set out the immediate and on-going management of the site, future monitoring arrangements for all secured measures and it should clearly identify the funding mechanisms in place to meet the management plan objectives. Also see A Guide for Ecological Consultants section of the website.
When is an ecology Survey Required?
building with nature standards framework
The Environment (Wales) Act 2016 and Planning Policy Wales - Edition 11 (PPW11) requires the Local Planning Authority to seek to enhance biodiversity through the planning process, the need for identification of biodiversity enhancements has been clarified in the letter from Welsh Government to Wales LPA Heads of Planning dated 23rd October 2019 which states:
Planning Policy Wales (PPW 11) sets out that “planning authorities must seek to maintain and enhance biodiversity in the exercise of their functions. This means that development should not cause any significant loss of habitats or populations of species, locally or nationally and must provide a net benefit for biodiversity” (para 6.4.5 refers). This policy and subsequent policies in Chapter 6 of PPW 11 respond to the Section 6 Duty of the Environment (Wales) Act 2016.
Where biodiversity enhancement is not proposed as part of an application, significant weight will be given to its absence, and unless other significant material considerations indicate otherwise it will be necessary to refuse permission.
It is important that biodiversity and ecosystem resilience considerations are taken into account at an early stage in development plan preparation and when proposing or considering development proposals. Planning authorities should be proactive and embed appropriate policies into local development plans to protect against biodiversity loss and secure enhancement.
The attributes of ecosystem resilience (PPW 11 para 6.4.9 p.138 refers to this) should be used to assess the current resilience of a site, and this must be maintained and enhanced post development. If this cannot be achieved, permission for the development should be refused.
Securing a net benefit for biodiversity within the context of PPW requires a pragmatic response to the specific circumstances of the site. Working through the step wise approach (PPW 11 para 6.4.21 refers), if biodiversity loss cannot be completely avoided (i.e., maintained), and has been minimised, it is useful to think of net benefit as a concept to both compensate for loss and look for and secure enhancement opportunities. A net benefit for biodiversity can be secured through habitat creation and/or long-term management arrangements to enhance existing habitats, to improve biodiversity and the resilience of ecosystems. Securing a net benefit for biodiversity is not necessarily onerous; through understanding local context, it is possible to identify new opportunities to enhance biodiversity.
Updated National Planning Policy for Chapter 6 of Planning Policy Wales was issued on 18 October 2023 (Minister for Climate Change letter to Heads of Planning, 11 October 2023 and Annex to Heads of Planning Letter, updated National Planning Policy for Chapter 6 of Planning Policy Wales, 11 October 2023). In this updated guidance a Green Infrastructure Statement should be submitted with all planning applications.
Please use the Council’s Supplementary Planning Guidance for Nature Conservation and Biodiversity and complete the checklists it contains.
Supplementary planning Guidance for Nature Conservation

Net benefit for Biodiversity (NBB) has an integral role in sustainable development and is fundamental to the social and economic wellbeing of Carmarthenshire’s residents.
Biodiversity enhancements are the features of a project or a planning application which will secure Net Benefits for Biodiversity (species and or habitats) as result of the proposed project being delivered.
Any planning proposal must demonstrate that it has both maintained and enhanced biodiversity and built resilient ecological networks through green infrastructure. Biodiversity enhancements that achieve NBB must be delivered following implementation of the stepwise approach, or mitigation hierarchy, of firstly avoiding, then minimising, mitigating and as a last resort compensating for, adverse impacts on the environment in a development. A Green Infrastructure Statement should be submitted with all planning applications.
Legislation and planning policy that apply in Wales now require that development must maintain and enhance biodiversity in the exercise of their functions. This means that development should not cause any significant loss of habitats or populations of species, locally or nationally and must provide a Net Benefit for Biodiversity.
The Chief Planning Officer in the Welsh Government has stated that
“Where biodiversity enhancement is not proposed as part of an application, significant weight will be given to its absence, and unless other significant material considerations indicate otherwise it will be necessary to refuse permission.”
(Chief Planner, Planning Directorate, Welsh Government, October 2019).
An ecologist will look at your proposals, they will advise how best to minimise any the impact of the development you propose on biodiversity, and what would be suitable in terms of enhancements.
Relatively small applications, for example extensions, householder applications and single dwelling developments:
An annotated plan should be submitted with your planning application - this should be in the form of a Green Infrastructure Statement which should be submitted with all planning applications - for example laying out areas of tree, hedgerow, shrub and pollinator planting (native plant species are preferred, but other nectar bearing plants can also be used in the garden context provided they are not invasive). An annotated plan of an elevation can show how bat features will be built in. Integrated bat and bird boxes should be used on new buildings as these are long lasting.
Potential applicants should not conduct any pre-emptive site clearance works before submitting a planning application as this can make it more difficult for a development proposal to secure a net benefit for biodiversity. Where a site has been cleared prior to development its biodiversity value should be deemed to have been as it was before any site investigations or clearance took place.
Biodiversity Net Benefit: Householders (Sir Fynwy / Monmouthshire)
These schemes will require professional ecological advice regarding the impact of the development on biodiversity, habitats, and species and how you will be delivering Net Benefit for Biodiversity. A Green Infrastructure Statement, which should be submitted with all planning applications, is a useful way of setting out how you will deliver a net benefit for biodiversity. Make sure that for proposals for Net Benefit for Biodiversity are integrated with any other landscaping and Nature Based SUDS proposals.
Planning authorities must follow a step-wise approach to maintain and enhance biodiversity - adverse effects are firstly avoided, then minimized, mitigated, and as a last resort compensated for – and secure the maintenance and enhancement of ecosystem resilience and resilient ecological networks by improving diversity, extent, condition, and connectivity i.e. the DECCA Framework.
Enhancement must be secured by delivering a biodiversity benefit primarily on site. A scheme of enhancements must be provided to ensure a net benefit for biodiversity. Pre-application surveys, research and data searches by developers will be necessary to establish the baseline state of biodiversity and ecosystem resilience.
The Building with Nature standards represents good practice and are an effective prompt for developers to improve the quality of their schemes and demonstrate the sustainable management of natural resources. The standards are underpinned by an accreditation system and whenever possible, accreditation under these standards should be pursued.
Each stage of the step-wise approach must be accompanied by a long term management plan. The management plan should set out the immediate and on-going management of the site, future monitoring arrangements for all secured measures and it should clearly identify the funding mechanisms in place to meet the management plan objectives. Also see A Guide for Ecological Consultants section of the website.
When is an ecology Survey Required?
building with nature standards framework
The Environment (Wales) Act 2016 and Planning Policy Wales - Edition 11 (PPW11) requires the Local Planning Authority to seek to enhance biodiversity through the planning process, the need for identification of biodiversity enhancements has been clarified in the letter from Welsh Government to Wales LPA Heads of Planning dated 23rd October 2019 which states:
Planning Policy Wales (PPW 11) sets out that “planning authorities must seek to maintain and enhance biodiversity in the exercise of their functions. This means that development should not cause any significant loss of habitats or populations of species, locally or nationally and must provide a net benefit for biodiversity” (para 6.4.5 refers). This policy and subsequent policies in Chapter 6 of PPW 11 respond to the Section 6 Duty of the Environment (Wales) Act 2016.
Where biodiversity enhancement is not proposed as part of an application, significant weight will be given to its absence, and unless other significant material considerations indicate otherwise it will be necessary to refuse permission.
It is important that biodiversity and ecosystem resilience considerations are taken into account at an early stage in development plan preparation and when proposing or considering development proposals. Planning authorities should be proactive and embed appropriate policies into local development plans to protect against biodiversity loss and secure enhancement.
The attributes of ecosystem resilience (PPW 11 para 6.4.9 p.138 refers to this) should be used to assess the current resilience of a site, and this must be maintained and enhanced post development. If this cannot be achieved, permission for the development should be refused.
Securing a net benefit for biodiversity within the context of PPW requires a pragmatic response to the specific circumstances of the site. Working through the step wise approach (PPW 11 para 6.4.21 refers), if biodiversity loss cannot be completely avoided (i.e., maintained), and has been minimised, it is useful to think of net benefit as a concept to both compensate for loss and look for and secure enhancement opportunities. A net benefit for biodiversity can be secured through habitat creation and/or long-term management arrangements to enhance existing habitats, to improve biodiversity and the resilience of ecosystems. Securing a net benefit for biodiversity is not necessarily onerous; through understanding local context, it is possible to identify new opportunities to enhance biodiversity.
Updated National Planning Policy for Chapter 6 of Planning Policy Wales was issued on 18 October 2023 (Minister for Climate Change letter to Heads of Planning, 11 October 2023 and Annex to Heads of Planning Letter, updated National Planning Policy for Chapter 6 of Planning Policy Wales, 11 October 2023). In this updated guidance a Green Infrastructure Statement should be submitted with all planning applications.
Please use the Council’s Supplementary Planning Guidance for Nature Conservation and Biodiversity and complete the checklists it contains.
Supplementary planning Guidance for Nature Conservation