Measuring ecological change – Using Defra Metric 3.0, 3.1 and 4.0

Defra Metric 3.0, 3.1 and 4.0 have been mapped to the BREEAM Change in Ecological Value Calculator and can be used in assessments for BREEAM UK New Construction 2018, BREEAM Infrastructure Version 6 (formerly CEEQUAL Version 6), and Home Quality Mark ONE.

Please see the table below for the applicable benchmarks where Defra Metric 3.0, 3.1 or 4.0 is used. The benchmarks from the Defra Metric are taken from the lowest score from the three metrics (Habitat, Hedgerow, River).

If a metric is not present, e.g. there is no river on the site, the score of 0 for that metric must be ignored when taking the lowest score.

Metric result Credits awarded
BREEAM (GN36) Defra Metric (3.0, 3.1, 4.0) BREEAM UK NC 2018 HQM ONE BREEAM Infrastructure V6
Less than 75% Less than -25% 0 0 0
Between 75% and 94% Between -24% and -6% 1 2 10
Between 95% and 104% Between -5% and 4% 2 4 20
Between 105% and 109% Between 5% and 9% 3 6 30
110% and above 10% and above 3 + 1 exemplary level credit 8 40

The above approach can be used to determine the percentage score that describes ecological change in Guidance Note 36 (Table 9: Reward Scale), if the following is also met:

  • A Suitably Qualified Ecologist confirms that they have used the Defra Metric tool to measure ecological change in line with up to date good practice regarding the Mitigation Hierarchy and Biodiversity Net-Gain including CIEEM, CIRIA & IEMA, 2019, Biodiversity Net Gain. Good practice principles for development: A practical guide (
  • The Methodology sections of the relevant ecology assessment issues are followed
  • All other relevant criteria are met
  • One calculation tool is used consistently throughout the development to determine the change in ecological value. i.e. A mixture of outputs from the BREEAM Ecological Change tool and Defra Metric cannot be combined

Alternatively, the BREEAM Change in Ecological Value calculator tool will continue to be accepted until stated otherwise.

03 Mar 2022 - Updated to clarify how Defra Metric 3.0 can be applied to current schemes
27 May 2022 - Updated to Defra Metric 3.1
21 Sep 2022 - Clarification on the figure to use from Defra Metric 3.0 or 3.1
14 Oct 2022 - Updated following rebrand of CEEQUAL to BREEAM Infrastructure
16 Feb 2023 - Added rules and clarification from KBCN1407.
01 Jun 2023 - Addition of DEFRA Metric 4.0