Phase 1 Habitat Survey – A Thing of the Past?

For many years, Phase 1 Habitat Surveys have been a familiar part of the planning and development process. They have provided ecologists with a standardised approach to identifying and mapping habitats, helping developers understand the ecological characteristics of a site.

However, habitat assessment methods have evolved. With the introduction of mandatory Biodiversity Net Gain (BNG) in England and the increasing use of the UK Habitat Classification (UKHab) system, traditional Phase 1 surveys are no longer the default approach for development projects.

Does this mean Phase 1 Habitat Surveys are now a thing of the past?

Although the methodology remains useful in certain circumstances, UKHab offers a more detailed approach to habitat classification that is better suited to many current planning and biodiversity assessment requirements.

What Is a Phase 1 Habitat Survey?

A Phase 1 Habitat Survey is a standardised method of identifying, classifying and mapping the habitats present on a site.

Developed by the Joint Nature Conservation Committee (JNCC), the methodology uses habitat categories, mapping colours and codes to record features such as grassland, woodland, scrub, hedgerows and waterbodies.

Traditionally, Phase 1 surveys have been used to provide an initial understanding of a site's habitats and identify areas that may require further ecological investigation.

For example, a survey might identify neutral grassland with the potential to support notable plant species or semi-natural broadleaved woodland that could provide habitat for protected species.

The findings can help inform development proposals, highlight potential ecological constraints and establish where more detailed assessments may be necessary.

However, while the methodology remains recognised, it was not originally designed to provide all the information now required for modern biodiversity assessments.

The Move Towards UK Habitat Classification (UKHab)

The UK Habitat Classification system, commonly referred to as UKHab, was developed to provide a more detailed and consistent approach to identifying and recording habitats.

Like Phase 1, UKHab allows ecologists to classify and map habitats. However, it offers a more comprehensive classification system, with greater flexibility to record habitat characteristics and ecological features.

The system uses a hierarchy of habitat categories alongside secondary codes that can capture additional information about a habitat, including relevant characteristics and management.

This additional detail is particularly valuable when assessing complex sites or preparing habitat information for Biodiversity Net Gain calculations.

UKHab is now widely used for ecological assessments associated with planning and development, although the appropriate survey methodology will depend on the purpose of the assessment.

Why Has UKHab Become More Important?

One of the main reasons for the increased use of UKHab is its relationship with Biodiversity Net Gain.

For developments in England that are subject to mandatory BNG requirements, the statutory biodiversity metric is used to calculate the biodiversity value of habitats before and after development.

These calculations take account of factors including habitat type, area, condition and strategic significance.

UKHab provides the principal habitat classification framework underpinning the terrestrial habitat categories used within the statutory biodiversity metric.

This means that accurate habitat identification is an important starting point for establishing a reliable biodiversity baseline.

For projects requiring BNG, a suitably detailed UKHab survey, alongside the relevant habitat condition assessments and any other necessary specialist surveys, is generally the more appropriate approach.

Phase 1 vs UKHab: What Is the Difference?

Although both methodologies are used to identify and map habitats, they differ in the level of detail they can provide and how the information is used.

Importantly, neither methodology should be confused with a complete ecological assessment.

A habitat survey records the habitats present, but additional work may still be needed to assess protected species, determine habitat condition or evaluate potential development impacts.

Does UKHab Replace a Preliminary Ecological Appraisal?

No. UKHab is typically conducted as part of Preliminary Ecological Appraisal (PEA). A PEA is a broader ecological assessment that typically combines a desk study with a site walkover to identify habitats, assess their potential to support protected or notable species, and establish whether further ecological work may be required.

For example, a UKHab may identify that a site contains other neutral grassland, mixed scrub and individual trees. The PEA then considers their potential to support species such as bats, breeding birds or reptiles.

For many development projects, combining these approaches provides a useful foundation for subsequent ecological assessments.

What Does This Mean for Developers and Planning Applications?

The shift towards UKHab has practical implications for the way ecological information is collected and used throughout the planning process.

Establishing an accurate biodiversity baseline

For developments subject to BNG requirements, habitat surveys help establish the site's existing biodiversity value.

Accurate classification is essential because different habitat types can have different biodiversity metric values and condition assessment requirements.

Where habitat information is incomplete or incorrectly classified, additional survey work may be needed before the biodiversity baseline can be finalised.

Informing development design

Detailed habitat information can help project teams understand which areas of a site may be suitable for development and which features could benefit from retention or enhancement.

For example, identifying a habitat of higher ecological value at an early stage may allow the development layout to be adjusted to reduce impacts.

This can also support the mitigation hierarchy, which prioritises avoiding ecological harm before considering mitigation or compensation.

Supporting Biodiversity Net Gain strategies

Where BNG applies, the baseline assessment informs decisions about habitat retention, enhancement and creation.

It can help developers understand the potential biodiversity units available on site, the implications of proposed habitat losses and whether additional measures may be required to meet the applicable BNG objective.

For larger or more complex developments, these findings can influence land requirements, long-term management commitments and project costs.

Identifying additional survey requirements

A UKHab survey may also identify habitats that require further investigation.

For example, grassland may need a more detailed botanical assessment, while woodland and hedgerows may warrant additional surveys depending on their characteristics and the proposed works.

Recognising these requirements early allows the appropriate surveys to be incorporated into the project programme.

The Future of Habitat Surveys

So, is the Phase 1 Habitat Survey a thing of the past?

Essentially yes, although ecologists may still need to have an understanding of the Phase 1 habitat criteria to interpret desk study data such as citations for designated sites.

However, UKHab provides a more detailed and flexible approach that aligns with many contemporary ecological assessment needs, particularly those associated with Biodiversity Net Gain.

At Ecology by Design, our experienced ecologists undertake habitat assessments and provide specialist advice on Biodiversity Net Gain, ecological constraints and development planning.

If you're planning a development and would like advice on the appropriate habitat surveys for your site, get in touch with our team.