Assessment

New layout: Please note that the layout of Mycelia has recently been updated, so things might look a bit different to the way they do in the video(s) on this page. You can learn more about the changes here.

Mycelia helps you to assess biodiversity data, and make informed decisions on progressing planning applications or habitat improvement plans. Each level of detail can be used separately, by different members of your team, or they can be used in conjunction with one another.

The Assessment workflow

Mycelia breaks assessment into four levels of detail. Work through them in order, or jump straight to the one you need:

• Level 1: Metric Errors – every confirmed breach of BNG rules, collected in one place.
• Level 2: Metric Summary Table – the headline figures, including whether the mandatory 10% net gain is met.
• Level 3: Metric Flow Diagram – a visual view of how every habitat changes from baseline to post-intervention.
• Level 4: Individual Habitat Cards – a dedicated page for each habitat, for detailed, habitat-by-habitat review.

Mycelia also includes an AI photo analyser to check habitat photos, and a separate Ecology Risks tool that flags potential ecological risks for your professional judgement.

Level 1: Metric Errors

Metric Errors is the first level of detail within Mycelia's Assessment workflow. It brings together every confirmed breach of BNG rules found in a submitted metric into a single, scannable list.

In the video below, learn about the errors Mycelia identifies in the metric.

What Metric Errors shows you

This goes beyond what Excel alone can catch. Mycelia identifies both:

• Spreadsheet errors – the red-cell validation errors that Excel flags within the metric
• Non-spreadsheet rule breaches – errors that fall outside Excel's built-in checks but still represent definite problems

Each error is translated into a plain-English explanation and includes a direct link to the specific habitat record involved, so you can jump straight to the source.

Why it matters

A biodiversity metric spreadsheet can contain up to 20 tabs. Manually reviewing each one for errors is slow and inconsistent. Mycelia collects every confirmed error into one place, so you can see all the problems at a glance without trawling through the entire workbook.

This supports faster, more consistent assessment across your team.

Errors vs. risks

Metric Errors show definite problems – clear breaches of BNG rules that need to be addressed. They are distinct from Ecology Risks, which flag areas that may require professional judgement or interpretation. Errors are black and white; risks involve shades of grey.

Where it fits in the workflow

Metric Errors is Level 1 of the Assessment workflow. It is the natural starting point before moving on to:

• Level 2: Metric Summary Table
• Level 3: Metric Flow Diagram
• Level 4: Individual Habitat Cards

Clearing confirmed errors first means you are working from a clean baseline when you move into the more detailed stages of assessment.

Level 2: Metric Summary Table

The Metric Summary Tables condense the information contained across up to 20 tabs of the biodiversity metric spreadsheet into a set of clear, high-level tables. This allows assessors to quickly understand what is happening in the metric before diving into detailed habitat-level data.

Learn about using the metric summary table in this video.

How the tables are structured

Each summary table has three rows, one for each habitat category:

• Area habitats
• Hedgerows
• Watercourses

The columns show the key stages of the metric:

• Pre-intervention – the baseline biodiversity value
• Losses – biodiversity units lost through development
• Post-intervention – the biodiversity value after proposed habitat creation or enhancement
• Net change – the difference in biodiversity units and the percentage net gain

Checking the 10% requirement

The net change column is where you assess whether the mandatory 10% biodiversity net gain has been met. This is calculated independently for each habitat category – area habitats, hedgerows, and watercourses must each meet the 10% threshold on their own.

On-site, off-site, and combined tables

What you see depends on the metric type:

• Small Sites Metric – shows on-site tables only
• Main Metric – shows on-site tables, off-site tables, and combined tables

For applications using the Main Metric, the combined table is the key reference point. This is where you confirm whether the overall 10% net gain requirement has been achieved across on-site and off-site provision together.

Alert triangles

You may see alert triangles next to some headline figures. These indicate that the numbers shown may not include all records – for example, where habitat records are incomplete or certain entries have been excluded from the calculation. Hover over the triangle for more detail.

Where it fits in the workflow

The Summary Tables are Level 2 of the Assessment workflow. Review them after clearing any Metric Errors (Level 1), and before moving into the more detailed levels: the Flow Diagram (Level 3) and Individual Habitat Cards (Level 4). They give you the big picture – whether the headline numbers stack up – so you know where to focus your detailed review.

Level 3: Metric Flow Diagram

The Metric Details Diagram, or flow diagram provides a visual representation of the entire biodiversity metric in a single view. Instead of piecing together information from up to 20 tabs of Excel, this feature tells the full story of the metric by showing how each habitat changes from the baseline, through proposed interventions, and to the final post-intervention outcome.

Learn about how to use the metric flow diagram in the video below.

How the diagram works

Each card in the diagram represents a single habitat. Cards are arranged in three columns:

• Pre-intervention – the baseline habitats on site before development
• Intervention – what happens to each habitat (retained, enhanced, lost, created)
• Post-intervention – the resulting habitats after all proposed changes

Hover over any habitat card to see flow lines showing its full journey across all three stages. This makes it straightforward to trace how a specific habitat is affected from start to finish.

Navigation and display controls

The diagram includes several tools to help you work with large or complex metrics:

• Smart scrolling – keeps related habitat journeys visible together as you move through the diagram
• Zoom controls – adjust the view for large or small screens
• Reorder cards – sort habitats by criteria such as highest biodiversity value first or largest habitats first
• Focus on filtering – show only specific distinctiveness levels or habitat types to cut through the noise
• On-site and off-site toggle – switch between on-site and off-site views

When to use it

The flow diagram is most useful when the headline figures from the Summary Tables raise questions. If the numbers look unexpected – gains seem too high, losses seem too low, or the overall story does not add up – the flow diagram lets you see exactly what is happening at the habitat level and trace the journey that produced those results.

Where it fits in the workflow

The flow diagram is Level 3 of the Assessment workflow. Use it after reviewing Metric Errors (Level 1) and Summary Tables (Level 2), and before moving into Individual Habitat Cards (Level 4) for the most detailed review.

Level 4: Individual Habitat Cards

• The Individual Habitat Record Pages provide the fourth and final level of detail within Mycelia's Assessment workflow. Each habitat in a biodiversity metric has its own dedicated page, bringing together:
  • all data pulled directly from the metric
  • any errors relating specifically to that habitat
  • photos submitted by the applicant
  • internal notes and review status

This allows assessors to carry out a systematic, detailed review of every habitat and maintain a clear audit trail.

The video below shows how to record and view information for individual habitats in Mycelia.

What each habitat page contains

Every habitat in the metric gets its own dedicated page. On it, you will find:

• Metric data – all the figures pulled directly from the biodiversity metric for that habitat
• Habitat-specific errors – any confirmed errors that relate to this particular record
• Applicant photos – any images submitted by the applicant for this habitat
• Internal notes – observations, questions, and decisions recorded during assessment
• Review status – whether the habitat has been marked as reviewed

Tracking your progress

Each habitat page has a Mark as reviewed button. Use this to record that you have checked a habitat, so you (and your colleagues) can see at a glance which habitats still need attention.

The navigation controls at the top of each page support this workflow:

• Outer buttons – step through every habitat in order
• Inner buttons – skip habitats that have already been reviewed, jumping straight to the next one that still needs checking

This avoids duplicating work and makes it easy to pick up where you or a colleague left off.

Recording notes

At the bottom of each habitat page is a notes section. Use it to record:

• Observations about the habitat data
• Questions to raise with the applicant or ecologist
• Decisions made during assessment
• Follow-up actions

Each note is automatically tagged with a reference to the habitat it relates to, so the context is always clear.

Copying notes

Use the Copy notes button to export all your notes at once. The habitat references are retained when copied, so you can paste them directly into emails, reports, or other documents without losing track of which note relates to which habitat.

Team-based workflows

Because review status and notes are shared, colleagues working on the same case can see which habitats have already been checked. This supports collaborative assessment and ensures nothing is missed when work is handed between team members.

Where it fits in the workflow

Individual habitat cards are Level 4 – the final and most detailed level of Mycelia's Assessment workflow. Use them after reviewing Metric Errors (Level 1), Summary Tables (Level 2), and the Flow Diagram (Level 3). This is where you carry out the granular, habitat-by-habitat review and build the audit trail for your assessment.

AI photo analyser

Biodiversity Metrics sometimes contain photos of the habitats. If a Biodiversity Metric contains photos, Mycelia shows you those photos, attached to the habitat they're labelled with in the Metric.

Mycelia helps to assess these photos, by using AI to check the photos and highlight potential issues.

The video below gives a quick overview of how this feature works.

What the AI photo analyser does

The AI photo analyser automatically reviews all habitat photos in a metric and checks whether each photo matches the habitat type it was submitted against. This saves you from having to manually review every photo yourself.

Where a photo matches the declared habitat, the AI confirms this. Where it doesn't match, the AI flags the issue and explains its reasoning – including suggested alternative habitat types and guidance on what additional evidence you may need to request.

How it helps your assessment

• Highlights risk early – flags photos where the habitat may not match what was submitted, so you can spot problems before they become bigger issues.
• Supports better decisions – gives you clear reasoning, suggested alternatives, and next steps rather than just a pass/fail result.
• Improves confidence and consistency – acts as a first-pass check across all photos, so nothing gets missed.
• Enables targeted follow-up – helps you decide when to investigate further, so you can focus your time where it matters most.

How to use it

You can access habitat photos from the habitat page within the metric diagram. Each photo is attached to the habitat it was labelled with in the metric.

You can switch between images to review them in sequence, and open any image in a separate tab if you need a closer look.

Which metrics include photos

Only the Small Sites Metric includes photos. If a submission uses the full Statutory Biodiversity Metric, photos will not be available for AI analysis.