Discover our glossary

Biodiversity Net Gain (BNG) is a new legal regime, In England, this has been phased in since January 2024. Because it is based on a statutory system, we have developed this Glossary to help people navigate the different terms. Wherever possible, we have used precise legal definitions of terms. Where no legal terms exist, we have used official Government guidance as much as possible or from expert bodies to source our definitions.

Because BNG is being introduced in England, the terms below - unless specified specifically - relate to England only. It is provided free for all.

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The accessibility to and within the site, for vehicles, cycles, and pedestrians in terms of the positioning and treatment of access and circulation routes and how these fit into the surrounding access network.


Adaptive Management

An approach which allows mitigation measures to be adjusted in response to greater certainty on effects following implementation. Also known as Dynamic Mitigation or Adaptive Planning.



A real increase in social value that would not have occurred in the absence of the intervention being appraised


Ancient Woodland

Any area that has been wooded continuously since at least 1600 AD, including:Ancient Semi-Natural Woodlands (ASNW); and Plantations on Ancient Woodland Sites (PAWS) Ancient Woodland sites are listed on the Ancient Woodland Inventory Database. If the woodland is less than 2ha, it needs to be checked against the criteria set out in the Ancient Woodland Inventory Handbook for features that indicate whether it may be ancient.



The aspects of a building or place within the development which determines the visual impression the building or place makes, including the external built form of the development, its architecture, materials, decoration, lighting, colour, and texture.


Area Habitat

Habitats recorded in the biodiversity metric tool in area (hectares).



The competent person completing the Biodiversity Metric. See also Competent Person.



Prevention of impacts occurring, having regard to predictions about potentially negative environmental effects (eg project decisions about site location or design)


Baseline Conditions

A description of existing conditions to provide a starting point (eg pre-project condition of biodiversity) against which comparisons can be made (eg post- impact condition of biodiversity), allowing the change to be quantified



The variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part: this includes diversity within species, between species and of ecosystems.


Biodiversity Action Plan (BAP)

Documents that were produced after the Convention on Biological Diversity at Rio de Janeiro in 1992. This stated that each country has the primary responsibility to save and enhance biodiversity, and the signatories agreed to draw up national plans and programmes and to share resources to help implement them.


Biodiversity Baseline

The pre-development biodiversity value of the onsite habitatSource:


Biodiversity Credits

Created under section 101 of the Environment Act 2021. Can only be used to offset biodiversity losses if it is not possible to secure gains onsite or via offsite units.


Biodiversity Gain Plan

Document which is required to comply with schedule 14 of the Environment Act 2021.


Biodiversity Metric, The

Tool used to measure biodiversity loss and gain in a consistent and robust way by using surrogate or proxy measures, which represent biodiversity. Created via schedule 14 of the Environment Act 2021.


Biodiversity Net Gain (BNG)

Development that leaves biodiversity in a better state than before. An approach where developers work with local governments, wildlife groups, land owners and other stakeholders to support their priorities for nature conservation.


Biodiversity Small Site Metric User Guide

Habitats recorded in the SSM in length (m). Three watercourse habitats are available.Source: Biodiversity Small Site Metric User Guide (Draft)


Biodiversity Units

Produced by the Biodiversity Metric. The metric calculates the values as ‘biodiversity units’. Biodiversity units are calculated using the size of the habitat, its quality and location and are used to describe relative biodiversity value. There are three types of biodiversity units: area habitat units, hedgerow units and watercourse units. Each of these are calculated in separate ‘modules’ of the biodiversity metric.


Brownfield Land

Land which is or was occupied by a permanent structure including the curtilage of the developed land (although it should not be assumed that the whole of the curtilage should be developed) and any associated fixed surface infrastructure. This excludes: land that is or was last occupied by agricultural or forestry buildings; land that has been developed for minerals extraction or waste disposal by landfill, where provision for restoration has been made through development management procedures; land in built-up areas such as residential gardens, parks, recreation grounds and allotments; and land that was previously developed but where the remains of the permanent structure or fixed surface structure have blended into the landscape.


Candidate SACs (cSACs)

See Special Area of Conservation (SAC)


Change of Use

Where there is a change in the purposes for which or the circumstances in which a building is used, so that after that change—

(a) the building is used as a dwelling, where previously it was not;

(b) the building contains a flat, where previously it did not;

(c) the building is used as an hotel or a boarding house, where previously it was not;

(d) the building is used as an institution, where previously it was not;

(e)the building is used as a public building, where previously it was not;

(f) the building is not a building described in classes 1 to 6 in Schedule 2, where previously it was;

(g) the building, which contains at least one dwelling, contains a greater or lesser number of dwellings than it did previously;

(h) the building contains a room for residential purposes, where previously it did not;

(i) the building, which contains at least one room for residential purposes, contains a greater or lesser number of such rooms than it did previously; or

(j) the building is used as a shop, where previously it was not.


Competent Person (Biodiversity Metric)

Someone who has the knowledge and skills to perform specified tasks to complete and review the Biodiversity Metric. Will usually need to be a Suitably Qualified Ecologist. Someone can become a competent person through training, qualifications, experience, or a combination of them.


Competent Person (Small Site Metric)

Someone who has the knowledge and skills to perform specified tasks to complete and review Small Site Metric (SSM) calculations. This can be obtained through training, qualifications, experience, or a combination of them. A competent person completing the SSM is known as the SSM ‘user’.



A measure of the habitat against its ecological optimum state. Condition is a way of measuring variation in the quality of patches of the same habitat type. You should conduct a condition assessment for all habitat parcels which require you to assign a condition to them in the biodiversity metric tool. You should use the biodiversity metric condition sheets to do this and provide these as evidence to support your assessment.Biodiversity metric condition sheets can be used to evidence good, moderate or poor condition. Fairly good and fairly poor are intermediate condition categories. If you need to use these, you should complete a biodiversity metric condition assessment sheet; make site specific judgements using ecological expertise; explain any deviations against specific condition criterion; provide ecological reasoning. You should not use the intermediate categories beyond a one-step adjustment from a standard condition sheet result (for example, from ‘moderate’ condition up to ‘fairly good’, or down to ‘fairly poor’) and they should not be used for the post-developSource:


Condition Assessment

The process of assigning habitat condition, to be undertaken by a competent person.



A measure of the functional availability of the habitats needed for a particular species to move through a given area. Examples include the flight lines used by bats to travel between roosts and foraging areas or the corridors of appropriate habitat needed by some slow-colonising species if they are to spread.


Conservation Duty

The condition is that any habitat enhancement will, by virtue of (a) a condition subject to which the planning permission is granted;(b) a planning obligation, or (c)a conservation covenant,be maintained for at least 30 years after the development is completed.


Conservation bank

A parcel of land managed for its conservation values. In exchange for permanently protecting the land, the bank owner is allowed to sell credits to parties who need them to satisfy legal requirements for compensating environmental impacts of development


Contaminated Land

Any land that, in the opinion of the local authority in whose area it is located, is in a condition due to substances in, on, or under the land, where: (a) Significant harm is occurring or there is a significant likelihood of such harm occurring; or (b) Significant pollution of controlled waters is occurring or there is a significant likelihood of such pollution occurring.


Culvert presence

Defined by the Flood and Water Management Act 2010. A covered channel or pipe designed to prevent the obstruction of a watercourse or drainage path by an artificial construction. Culverted sections of any watercourse type should be recorded as ‘culvert’.


Cumulative impact/effect

Additional changes caused by a proposed development along with other developments or the combined effect of a set of developments taken together. In ecological terms cumulative effects may derive from a combination of effects from a development project with other past, present or reasonably foreseeable future projects. They may also result from time- or space-crowding of development combined with the effects of stochastic events/changes, including climate change. Cumulative impacts is the total arising from the project (under the control of the developer), other activities (that may be under the control of others, including developers, local communities, government) and other background pressures and trends that may be unregulated. The project’s impact is one part of the total cumulative impact on the environment. The analysis of a project’s incremental impacts combined with the effects of other projects can often give a more accurate understanding of the likely results of the project’s presence than considering its impacts in isolation



The carrying out of building, engineering, mining or other operations in, on, over or under land, or the making of any material change in the use of any buildings or other land.



A measure which represents the uncertainty in the effectiveness of management techniques used to enhance or create habitat.



A measure based on the type of habitat and its distinguishing features. This includes consideration of species richness, rarity, the extent to which the habitat is protected by designations and the degree to which a habitat supports species rarely found in other habitats.



Does not include a building containing one or more flats, or a flat contained within such a building.


EIA Application

An application for planning permission for EIA development; or a subsequent application in respect of EIA development


EIA Development

A development which is either a—

(a) Schedule 1 development; or

(b) Schedule 2 development likely to have significant effects on the environment by virtue of factors such as its nature, size or location


Ecological equivalence

Species that occupy similar niches in different geographical regions. In the context of biodiversity offsets, the term is synonymous with the concept of ‘like-for-like’ and refers to areas with highly comparable biodiversity components. This similarity can be observed in terms of species diversity, functional diversity and composition, ecological integrity or condition, landscape context (eg connectivity, landscape position, nearby land uses or condition, patch size), and ecosystem services (including people’s use and cultural values)


Ecological feature

Habitats, species or ecosystems.


Ecological network

An interconnected system of ecological corridors


Ecologist / Suitably Qualified Ecologist

An individual who: Holds a degree or equivalent qualification (e.g. N/SVQ Level 5) in ecology or a related subject Is a practising ecologist, with a minimum of three years’ relevant experience (within the last five years). Such experience must clearly demonstrate a practical understanding of factors affecting ecology in relation to construction and the built environment, including acting in an advisory capacity to provide recommendations for ecological protection, enhancement and mitigation measures. Examples of relevant experience are ecological impact assessments, Phase 1 and 2 habitat surveys, and habitat restoration Is covered by a professional code of conduct and subject to peer review.



A dynamic complex of plant, animal and micro-organism communities and their non-living environment interacting as a functional unit


Ecosystem Services

Services provided by the natural environment that benefit people.



Improved management of ecological features or provision of new ecological features, resulting in a net benefit to biodiversity, which is unrelated to a negative impact or is ‘over and above’ that required to mitigate/compensate for an impact.


Environment Act 2021

Inland waters, except groundwater; transitional waters and coastal waters, except in respect of chemical status for which it shall also include territorial waters.Source: Environment Act 2021


Environmental Information

The Environmental Statement including any further information and any other information, any representations made by any body required by the Town and Country Planning (Environmental Impact Assessment) Regulations 2011 to be invited to make representations, and any representations duly made by any other person about the environmental effects of the development.


Environmental Land Management Schemes

There are new environmental land management schemes will help achieve thriving plants and wildlife by paying for measures such as habitat creation and restoration as well as species management actions. The environmental land management schemes will work alongside mandatory biodiversity net gain as another source of income to enhance biodiversity and the wider environment.


Environmental Net Gain

An approach to development that leaves the natural environment in a measurably better state than it was beforehand. It was set out as a vision in the UK Government’s 25 Year Environment Plan, and biodiversity net gain is the first step to achieving it. Environmental net gain means building on biodiversity net gain and going further to achieve increases in the capacity of affected natural capital to deliver ecosystem services and make a scheme’s wider impacts on natural capital positive.

Tools such as the The Environmental Benefits from Nature Tool (EBNT) (formerly the EcoMetric) which can be used alongside biodiversity metric, and will enable some of these wider natural capital impacts of development to be understood. The EBNT may be used when delivering biodiversity net gain to facilitate better design.


Environmental Statement

A statement that includes the following information: 

Description of the development, including in particular—

(a)a description of the physical characteristics of the whole development and the land-use requirements during the construction and operational phases;

(b)a description of the main characteristics of the production processes, for instance, nature and quantity of the materials used;

(c)an estimate, by type and quantity, of expected residues and emissions (water, air and soil pollution, noise, vibration, light, heat, radiation, etc) resulting from the operation of the proposed development.

An outline of the main alternatives studied by the applicant or appellant and an indication of the main reasons for the choice made, taking into account the environmental effects.

A description of the aspects of the environment likely to be significantly affected by the development, including, in particular, population, fauna, flora, soil, water, air, climatic factors, material assets, including the architectural and archaeological heritage, landscape and the inter-relationship between the above factors.

A description of the likely significant effects of the development on the environment, which should cover the direct effects and any indirect, secondary, cumulative, short, medium and long-term, permanent and temporary, positive and negative effects of the development, resulting from

(a)the existence of the development;

(b)the use of natural resources;

(c)the emission of pollutants, the creation of nuisances and the elimination of waste,

and the description by the applicant or appellant of the forecasting methods used to assess the effects on the environment.

A description of the measures envisaged to prevent, reduce and where possible offset any significant adverse effects on the environment.

A non-technical summary of the information provided [under the above]

An indication of any difficulties (technical deficiencies or lack of know-how) encountered by the applicant or appellant in compiling the required information.

It should be the information that is reasonably required to assess the environmental effects of the development and which the applicant can, having regard in particular to current knowledge and methods of assessment, reasonably be required to compile, but that includes at least the following: 

A description of the development comprising information on the site, design and size of the development.

A description of the measures envisaged in order to avoid, reduce and, if possible, remedy significant adverse effects.

The data required to identify and assess the main effects which the development is likely to have on the environment.

An outline of the main alternatives studied by the applicant or appellant and an indication of the main reasons for the choice made, taking into account the environmental effects.

A non-technical summary of the information provided [under the above]


European Site / European Marine Site

A term that was established during Brexit to describe sites that, previously defined and protected under EU law, would instead have their status enshrined in UK law. Defined by Regulation 8 of the Conservation of Habitats and Species Regulations 2017, European Sites include:

  • Special Areas of Conservation
  • Sites of Community Importance which has been placed on the list referred to in the third sub-paragraph of Article 4(2) of the Habitats Directive (list of sites of Community importance)
  • a site hosting a priority natural habitat type or priority species protected in accordance with Article 5(4) of the Habitats Directive
  • an area classified pursuant to Article 4(1) or (2) of the old Wild Birds Directive or the new Wild Birds Directive
  • Sites set out in accordance with Article 4(1) of the Habitats Directive before the UK left the EU (link)

The Secretary of State must keep a list of all European Sites. 



Any case where land not normally covered by water becomes covered by water.


Floor Space

The total floor space in a building or buildings.


Green infrastructure

A network of multi-functional green and blue spaces and other natural features, urban and rural, which is capable of delivering a wide range of environmental, economic, health and wellbeing benefits for nature, climate, local and wider communities and prosperity



All water which is below the surface of the ground in the saturation zone and in direct contact with the ground or subsoil. The UK Government has adopted the same definition as the EU’s Water Framework Directive



The place or type of site where an organism or population naturally occurs. It is often used in the wider sense referring to major assemblages of plants and animals found together. Source: CIEEM


Habitat Parcel

A linked area of habitat of the same distinctiveness, condition and strategic significance.


Habitat Quality

The SSM scores habitats of different types according to their relative biodiversity value. Habitats that are scarce or declining typically score highly relative to habitats that are more common and widespread.


Habitat type

A habitat classification used in Biodiversity Metric 4.0, derived from multiple sources, including: UK Habitat Classification Annex I habitats for Natura 2000 European Nature Information System habitat types Water Framework Directive (WFD) Lake typologies


Hedges and lines of trees

Habitats recorded in the SSM in length (m). Nine hedgerow and lines of tree habitat types are available.


Hibernaculum / hibernacula

Shelter of a hibernating animal.


Householder Application

An application for planning permission for development for an existing dwellinghouse, or development within the curtilage of such a dwellinghouse for any purpose incidental to the enjoyment of the dwellinghouse, or an application for any consent, agreement or approval required by or under a planning permission, development order or local development order in relation to such development, but does not include an application for change of use or an application to change the number of dwellings in a building.


Invasive Species

In UK law, these are defined as any species of animal, plant, fungus or micro-organism included from time to time on the list of species listed in Regulation (EU) No 1143/2014


Irreplaceable habitat

Blanket bog, Lowland fens, Limestone pavements, Coastal sand dunes, Ancient woodland, Ancient trees and veteran trees, Spartina saltmarsh swards and Mediterranean saltmarsh scrub. Source: The Biodiversity Gain Requirements (Irreplaceable Habitat) Regulations 2024.



The treatment of land (other than buildings) for the purpose of enhancing or protecting the amenities of the site and the area in which it is situated. Includes screening by fences, walls or other means; the planting of trees, hedges, shrubs or grass; the formation of banks, terraces or other earthworks; the laying out or provision of gardens, courts, squares, water features, sculpture or public art; and the provision of other amenity features.


Lawton’s principles

Principles for enhancing England’s wildlife sites were developed by British ecologist John H. Lawton. They are commonly referred to as ‘Lawton’s principles’, and have been summarised as enhancing wildlife sites to be “bigger, better and more joined up”.



The way in which buildings, routes and open spaces within the development are provided, situated and orientated in relation to each other and to buildings and spaces outside the development.



Conservation (through the biodiversity offset) of the same type of biodiversity as that affected by the development project. Sometimes referred to as in-kind. Can also be ‘like-for-like or better’ or ‘trading up’.


Linear habitat

Habitats recorded in the metric according to length (kilometres) rather than area (hectares). This includes habitats in the hedgerow and watercourse modules and is taken as a centre line measurement along the length of the feature.


Local Nature Recovery Strategies

Local Nature Recovery Strategies are locally produced spatial planning frameworks for nature, informed by national maps and priorities. Each strategy will, for the area it covers, agree priorities for nature’s recovery, map the most valuable existing areas for nature and map specific proposals for creating or improving habitat for nature and wider environmental goals. They are mandated by the Environment Act 2021.


Local Plan

Also known as a Development Plan, these were mandated in the Planning and Compulsory Purchase Act of 2004 (link). These are plans for the future development of a local area, drawn up by the local planning authority in consultation with the community. A local plan can consist of either strategic or non-strategic policies, or a combination of the two.


Major Development

Development involving any one or more of the following: the winning and working of minerals or the use of land for mineral-working deposits; or waste development; or the provision of dwellinghouses where the number of dwellinghouses to be provided is 10 or more, or the development is to be carried out on a site having an area of 0.5 hectares or more and it is not known whether the development falls within the specified criteria listed above; the provision of a building or buildings where the floor space to be created by the development is 1,000 square metres or more; or development carried out on a site having an area of 1 hectare or more.


Marine Conservation Zone

A zone designated under section 116 of the Marine and Coastal Access Act 2009.



Masterplans set the vision and implementation strategy for a development. They are distinct from local design guides by focusing on site specific proposals such as the scale and layout of development, mix of uses, transport and green infrastructure. Depending on the level of detail, the masterplan may indicate the intended arrangement of buildings, streets and the public realm. More specific parameters for the site’s development may be set out in a design code, which can accompany the overall masterplan.


Minor Commercial Application

An application for planning permission for development of an existing building or part of a building currently in use for any of the purposes falling within Part A of the Schedule to the Town and Country Planning (Use Classes) Order 1987, or an application for any consent, agreement or approval required by or under a planning permission, development order or local development order in relation to such development, where such an application does not include a change of use, a change to the number of units in a building, or development that is not wholly at ground floor level or that would increase the gross internal area of a building.



Measures taken to avoid or reduce negative impacts and effects. Measures may include locating the development and its working areas and access routes away from areas of high ecological interest, fencing off sensitive areas during the construction period, or timing works to avoid sensitive periods. An example of a reduction measure is a reed bed silt trap that is designed to minimise the amount of polluted water running directly into an ecologically-important watercourse. Depending on circumstances, mitigation measures may be located within or outside the project site. Measures that aim to reduce impacts to the point where they have no adverse effects. Examples of mitigation measures include avoidance of sensitive sites or disruptive work at sensitive times (eg breeding seasons), translocation of species to temporary or permanent alternative sites, post-project site restoration and recolonisation/stocking and the creation of similar habitats to offset residual impacts  


Mitigation hierarchy

A hierarchical sequence of actions to anticipate and avoid impacts on biodiversity or ecosystem services. Where avoidance is not possible, minimise; where impacts occur, restore; and finally where significant residual impacts remain, offset. In the UK the approach is set out in NPPF.


National Conservation Sites

A site of special scientific interest; A national nature reserve; A Ramsar site; a marine conservation zone; a European site: Environment Act 2021.


National Nature Reserves (NNRs) / Nature Reserves

Areas declared under Section 19 of the National Parks and Access to the Countryside Act 1949 or Section 35 of the Wildlife and Countryside Act 1981


Natural Environment

a) Plants, wild animals and other living organisms,

b) Their habitats,

c) Land (except buildings or other structures),

d) Air and water,

and the natural systems, cycles and processes through which they interact.


Natural capital

The elements of nature that directly and indirectly produce value or benefits to people, including ecosystems, species, freshwater, land, minerals, the air and oceans, as well as natural processes and functions


Nature Recovery Network (NRN)

A connected network of places for nature, including Sites of Special Scientific Interest.



Interventions on land outside of the on-site boundary, regardless of proximity or ownership



Land within the boundary of a project. In a planning context, this usually means within the red line boundary of a planning application.



When the biodiversity conserved through the offset differs in-kind from the biodiversity impacted by the project. The option of ‘trading up’ to an out-of-kind offset may be advisable where an offset arising from a project impacts on a common or widespread component of biodiversity. This may instead be switched to benefit a more threatened or rare component.


Outline Planning Permission

A planning permission for the erection of a building, which is granted subject to a condition requiring the subsequent approval of the local planning authority with respect to one or more reserved matters.



See Habitat Parcel


Particulate matter (PM)

Anything in the air which is not a gas. It can come from natural or human-made sources and be formed through chemical reactions between pollutants in the atmosphere. PM2.5 is particulate matter with a diameter of 2.5 microns or less, which is one 400th of a millimetre.


Planning Obligation

An obligation entered into by agreement or otherwise by any person interested in land pursuant to section 106 of the 1990 Act (planning obligations).


Priority Natural Habitat Type

Natural habitat types in danger of disappearance, as defined by the EU Habitats Directive (and especially Annex I thereof)


Priority Species

Endangered species as defined by the EU Habitats Directive (and especially Annex II thereof)


Project timeframe

The timeframe over which the metric calculates gains and losses for specific habitat interventions.


Protected Species / European Protected Species

Species that are listed in the EU Habitats Directive which have a natural range which includes any area in Great Britain.


Protected site / Protected Area

An internationally or European protected site:

  • Special Area of Conservation (SAC)
  • Special Protection Area (SPA)
  • Ramsar Wetland:
  • Potential SPA, possible SAC or proposed Ramsar Wetland

A nationally protected site:

A locally protected site:

  • Local Nature Reserve
  • Local Wildlife Site
  • Local Geological Site

A protected area:

  • National park or the Norfolk and Suffolk Broads
  • Area of Outstanding Natural Beauty
  • Heritage Coast

Ramsar Sites / Proposed Ramsar Sites

Sites designated under Section 37A of the Wildlife and Countryside Act 1981 in compliance with the Convention of Wetlands of International Importance,1971(as amended)


Reserved Matters

In relation to an outline planning permission, or an application for such permission. Means any of the following matters in respect of which details have not been given in the application: access, appearance, landscaping, layout, and scale.



A person reviewing the metric. Usually from a determining body or planning authority.



Where new habitat is created, or existing habitat is enhanced, the difficulty and associated risks of doing so



Except in the term ‘identified scale’, means the height, width, and length of each building proposed within the development in relation to its surroundings.



The site or part of the site in respect of which outline planning permission is granted or, as the case may be, in respect of which an application for such a permission has been made.


Sites of Community importance (SCI)

See Special Area of Conservation (SAC)


Sites of Special Scientific Interest (SSSI)

Land which has been deemed, by Natural England, to be of special interest by reason of any of its flora, fauna, or geological/physiographical features



The size of the habitat parcel to be retained, enhanced, created, or lost. Size is measured in hectares for area features or in kilometres for linear features.


Small Site

Developments which do not fall under the meaning of major development. This includes:

  • Residential development where the number of dwellings is between 1 and 9
  • Commercial development where floor space created is less than 1,000 square metres or total site area is less than 1 hectare
  • Development that is not the winning and working of minerals or the use of land for mineral-working deposits development that is not waste development

Small Site Metric

A special version of the Biodiversity Metric that can be used if the development falls under the definition of a ‘Small Site’.


Spatial risk

Spatial risk represents the relationship between the location of biodiversity loss (on-site) and where the off-site habitat is being delivered. This is applied to off-site interventions only.


Special Area of Conservation (SAC)

A sub-set of European Site. 

Special Areas of Conservation (SACs) are sites that have been formally designated by the government of each country in whose territory the site lies. Sites of Community Importance (SCIs) are sites that were adopted by the European Commission before the end of the Transition Period following the UK's exit from the EU, but not yet formally designated by the government of each country. Under regulation 17(1)(a) of the Conservation of Habitats and Species Regulations 2017, the Secretary of State, must provide a list of SACs 

Candidate SACs (cSACs) are sites that were submitted to the European Commission, before the end of the Transition Period following the UK's exit from the EU, but were not formally designated. By 2021 all SCIs and cSCIs had become SACs.

These have been defined as a ‘European site’ under section 8 of the Conservation of Habitats and Species Regulations 2017 (link) and section 27 of The Conservation of Offshore Marine Habitats and Species Regulations 2017, link. By virtue of being a European Site, this is also classed as a ‘National conservation site’ in section 108 of the Environment Act 2021 (link)


Special Protection Area (SPA)

A sub-set of European Site. Special Protection Areas are sites across the United Kingdom’s territory which are most suitable in number and size for the conservation of the species listed in Annex 1 to the new Wild Birds Directive which naturally occur in that territory, and the conservation of regularly occurring migratory species of birds not listed in Annex 1 which naturally occur in that territory,The Special Protection Areas are set out here.Source Conservation of Habitats and Species Regulations 2017

The Special Protection Areas are set out here.


Species Abundance Target

The Environment Act requires a legally binding target on species abundance for 2030 to halt the decline of nature.


Species Conservation Strategies

Strategies developed by Natural England for improving the conservation status of any species of flora and fauna. It must relate to an area consisting of England or any part of England. Such a strategy for a species may in particular:

  • identify areas or features in the strategy area which are of importance to the conservation of the species,
  • identify priorities in relation to the creation or enhancement of habitat for the purpose of improving the conservation status of the species in the strategy area,
  • set out how Natural England proposes to exercise its functions in relation to the species across the whole of the strategy area or in any part of it for the purpose of improving the conservation status of the species in the strategy area,
  • include Natural England’s opinion on the giving by any other public authority of consents or approvals which might affect the conservation status of the species in the strategy area, and
  • include Natural England’s opinion on measures that it would be appropriate to take to avoid, mitigate or compensate for any adverse impact on the conservation status of the species in the strategy area that may arise from a plan, project or other activity.

Strategic significance

Describes the local significance of the habitat based on its location and the habitat type.


Temporal risk / Time to target condition

The average time lag between the start of habitat creation or enhancement works and the target outcome.



The competent person completing the Small Site Metric.


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