Best Practice Principles To Support Biodiversity Net Gain In Housing Developments

Apply the mitigation hierarchy

The first consideration should be evaluating how to reduce or minimise the impact the development will have on nature.

This can be done through mitigation hierarchy, which is a concept that is widely used to manage biodiversity impacts.

Mitigation hierarchy is comprised of four phases:

• Avoidance – this initial element of mitigation asks that developers question whether a site can be avoided all together or whether alternative development practices can be used. Another form of avoidance is restricting how much of a development site can be used for development.
• Minimisation – where there are no other options available, only then should developers proceed with finding steps to prioritise how to offset the effects on biodiversity from their development.
• Restoration – supporting new habitats or enhancing existing ones can help mitigate the effect on habitats before and throughout site development.
• Offsetting – this final step is required where impacts on nature and biodiversity from site development were unavoidable and need to be offset. This can be done on-site or offsite with methods that could be similar to restoration but elsewhere on the site or offsite.

Offsetting BNG off-site can be a complex option because a third party will need to be sourced, financed and managed to ensure the 10% uplift in BNG is reached.

Expert advice from ecologists, such as those at Fera, can help make the most effective decisions for the longevity of habitats and nature friendly land use.

Read more here.

Make a measurable net gain contribution

Once the mitigation hierarchy has been applied to a site development plan, developers are required to also think about how their plans can be measurable.

Planners should be considering how they will leave a traceable gain for biodiversity and ecosystems. These gains should endeavour to support wider conservation strategies locally and nationally in addition to each individual site’s BNG aims.

Avoid losing biodiversity that cannot be offset by gains elsewhere

Losing elements of the natural habitat that are complex to directly replace is a consideration that developers will need to address when planning to develop land.

An example is replacing the habitat of an ancient oak. Given the age of the tree, its features and habitat cannot be replaced overnight, so a bespoke plan is required to replace it as a habitat.

An oak tree can live on average 600 years and host around 280 types of insect species. So, if tree removal cannot be avoided in the site building process, a selection of other native trees appropriate to the local environment of the oak would need to be planted to help offset the lost habitat.

This tree selection would need to provide the equivalent seeds, wood, flowers and foliage to achieve the same level and quality of biodiversity present in the oak tree.

Address risks to existing habitats

Risk in the context of BNG relates to the risk to existing habitats on a development site.

For example, if a large section of habitat such as hedgerow is removed for development, there is a risk to biodiversity because hedgerows take several years to establish.

Therefore, the time it takes for biodiversity gains to show in a development site BNG action plan will need to be considered to offset the risks associated with the development and its impact on biodiversity.

Be inclusive and equitable

Executing a plan to improve biodiversity in a specific area and time frame is more likely to be successful if relevant stakeholders are engaged with the plan and understand what the objectives of it are.

This could include education on what BNG is, what the benefits of improving biodiversity are for nature and society, that the plans will be long-term, and that visible benefits may take a while to establish.

Educating stakeholders will encourage them to consider how they can contribute to improving the natural environment around them for the better.

Achieve the best outcomes for biodiversity

For developers to achieve the best possible results for biodiversity they need to use evidence to justify their decisions in the BNG planning process and consider making changes which benefit the local environment as well as on a national scale.

Replacing a lost section of habitat with one which has a greater benefit to nature is a preferable move.

For example, replacing lost grassland with a section of woodland to give more species of plants and animals protection, food and a place to thrive will give a much greater benefit to biodiversity levels.

Be additional

This principle has been created to ensure BNG plans achieve outcomes for biodiversity ‘in addition’ to naturally occurring ones.

For example, adding a varied mix of shrubs and trees to an already existing line of hedges will enhance the habitat because it will add more shelter for animals or increase food supply, such as berries for birds.

Create a net gain legacy

This holistic principle means that plans made to achieve BNG are sustainable both in terms of cost of investment but also ecologically.

For example, that they will survive extreme weather caused by climate change and will be beneficial to nature long-term, beyond the 30-year target, or even permanently.

The legacy here also should make sure net gain plans are future proofed, for example ensuring plans are protected from other land use changes or will avoid moving harmful activities from one site to another.

The advice of highly experienced ecologists such as those at Fera will help developers make decisions that will make a long-term impact.

Planning ahead

To find out more about how Fera can provide a range of services to support developers in their efforts to enhance nature and biodiversity, please visit here (fera.co.uk).

More about LAND360

LAND360 is Fera's cutting-edge natural capital assessment service. Launched in 2022, it empowers farmers, landowners, estate managers, and housing developers to make informed land use decisions. By accurately measuring and mapping existing land habitat features and modelling biodiversity offerings, LAND360 is a vital tool in the quest for sustainable development and biodiversity enhancement.