What’s the difference? Navigating distinctions between preliminary and BNG baseline reports and traditional surveys

5 Apr 2024 | 4 min read

What’s the difference? Navigating distinctions between preliminary and BNG baseline reports and traditional surveys

Most developers and ecologists have worked with several existing methods to survey vegetation. But it is important to understand that the scopes of these surveys vary, and they do not fully align with the BNG classifications established by the Defra Statutory Biodiversity Metric.

A BNG application requires information beyond traditional reporting. The comparison chart below depicts the differences.

Report or Survey type
Phase 1 Extended Phase 1 Preliminary Ecological Appraisal (PEA)
Preliminary BNG Assessment
BNG Baseline
Report: PDF, SHP, EXL Definition
Desktop Study PEA
PDF, SHP Habitat map — using standard classification (reflecting desk-based,
preliminary or pre-development habitat survey map status)
PDF Site overview — basic information concerning site context and proximity
to national designation sites
Optional Optional Local environmental record centre search for protected species within
and near proximity
Priority habitat map (broad and priority habitat – BAP)
Changes identified in priority habitat mapping from field survey
Species composition, management, vegetation structure, age, and
permanence of habitat
Indicative or estimated condition valuation
Habitat condition (field survey using the BNGAI survey application)
Habitat condition assessment sheet
Possible presence of protected species and additional survey
Non-native invasive species detection and map
Identification of any constraints and opportunities for enhancement
Strategic significance: local nature recovery strategy (LNRS) or public
data aligned with guidance
River encroachment mapping (coming soon)
River encroachment assessment and validation (coming soon)
Screening for veteran tree and irreplaceable habitat
BNG calculations (indicative and final)
PEA Preliminary Baseline Reports (preliminary, PEA, biodiversity habitat report)
EXL Statutory Biodiversity Metric or Small Site Metric calculation sheet
Post-development planning support (import drawing, plans such as DWG
files, etc.), habitat enhancement, creation planning tools, and
exportable mapping software
PDF, SHP Post-development plan habitat map
SHP Shape files of baseline and post-development map polygons

For example, a preliminary report includes a detailed habitat map with background data that’s essential to derive an indicative calculation of BNG prior to your field survey. Even at the time of production, our software enables you to add development plans to gain an early insight to the potential post-development impact. Plus, you can include a local environmental record centre search, to provide early risk identification of protected species.

Next, a field survey is needed to validate your habitat data, identify any risks for protected species and further survey requirements and to undertake the condition assessment. Once completed, this is included as part of your baseline report for the site. Essentially, this combines the Preliminary Ecological Appraisal (PEA) and a detailed assessment for BNG into one report.

Remember, all this data is retained in the BNGAI platform, and you can access BNG calculations instantly as the data is updated. This covers steps 1-3 in our BNG application process stages.

BNGAI allows you to print the report when needed, create planning scenarios with ease, and continually add data to the platform.

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