This multiplier represents the uncertainty in the effectiveness of techniques to create or enhance habitats. The metric automatically assigns the delivery risk and score for each habitat, based on its habitat intervention category (creation or enhancement). 7.2.2. Despite this partial accounting for risk in the metric, proposals must still be based on sound ecological judgement and should consider the ecological context of the change.

The temporal risk multiplier represents the average time lag, measured in years, between the start of habitat creation or enhancement works and the target outcome. This is known known as ‘time to target condition’ (7.3.1, Natural England, Biodiversity Metric 4.0 User Guide, link).

This multiplier is automatically applied by the metric and changes depending on data input.

According to the Government:

'The use of multipliers to account for risks associated with habitat creation or enhancement has several benefits:

Technical Annex 2, 5.1.1, link

Values for time to target condition are fixed within the metric and vary depending on the habitat type, habitat condition and whether the habitat is created or enhanced (Technical Annex 2, 5.1.3, link)

Note that the Government states ‘With sufficient time and money most habitats can be recreated more rapidly but allowing a more gradual process may be more beneficial to wildlife in the longer term’ (Technical Annex 2, 5.2.2, link)

The times to target condition have a ‘discounting rate’ applied to generate the multiplier value used in the metric.

This function accounts for delays in habitat works by increasing the time to target condition value proportionate to length of delay. Note that if the length of delay combined with the ‘standard’ time to target condition exceeds 30 years, then the 30+ years multiplier will be applied.

A temporary loss is where there is restoration of a habitat, to its baseline type and condition within 2 years of the date of initial habitat loss, delivered in the same location. Where this applies, the habitat may be entered into the metric as ‘retained’. Habitats subject to temporary losses can still be recorded as ‘enhanced’. However, a 1- or 2-year temporal risk multiplier should be applied through the ‘Delay in starting habitat creation or habitat enhancement’ function (7.3.7 in Biodiversity Metric 4.0, Natural England, Biodiversity Metric 4.0 User Guide, link)

Use of advance or delayed habitat creation or enhancement 7.3.2. The metric can account for habitat that is created or enhanced in advance of a loss, or where habitat creation or enhancement is delayed. These functions are available for both on and off-site delivery for all habitat types. 7.3.3. Examples of when to use the creation in advance function including habitat banks, or where project phasing results in compensation ahead of losses. If the ‘Habitat created or enhanced in advance’ years function is used, provide evidence that the target condition of the habitat created in advance is being met.

. The ‘delay in starting habitat creation or enhancement’ years function should be used when there is a delay between habitat loss and the start of habitat creation and enhancement works. For example, if land for habitat creation does not become available until the end of the construction. 7.3.5. When these functions are used, justification and evidence must be provided to the consenting body or planning authority. For example, assessors should reference project phasing plans or any additional agreements. Accounting for temporary losses 7.3.6. A temporary loss is where there is restoration of a habitat, to its baseline type and condition within 2 years of the date of initial habitat loss, delivered in the same location. Where this applies, the habitat may be entered into the metric as ‘retained’. 7.3.7. Habitats subject to temporary losses can still be recorded as ‘enhanced’. However, a 1- or 2-year temporal risk multiplier should be applied through the ‘Delay in starting habitat creation or habitat enhancement’ function.

Where a project cannot achieve a net gain in biodiversity units on-site, then off-site units can be used. All off-site data should be entered into the off-site sheets of the metric. 7.4.2. The spatial risk multiplier reflects the relationship between the location of on-site biodiversity loss and the location of off-site habitat compensation. It affects the number of biodiversity units provided to a project by penalising proposals where off-site habitat is located at distance from the impact site. 7.4.3. Assessors should use the descriptions provided in Table 7-1 to determine the correct spatial risk multiplier score.

Source: 6.4.3, Natural England, Biodiversity Metric 4.0 User Guide, link