Ask the expert: Biodiversity – ADC

What services/benefits can a biodiversity consultant bring to development projects?

Traditionally, a biodiversity consultant would have focussed on the ecology of a project and be involved in the survey, assessment, and mitigation of protected/priority species and habitats.

At Biodiverse Consulting we take this further. We offer a range of environmental surveys and assessments, including biodiversity net gain services, nutrient pollution assessments, and carbon calculations. This data is then used to advise and guide developers and reassure statutory agencies that the best practice is to support nature’s recovery.

What is biodiversity net gain and how does it relate to the Environment Act and the wider built environment?

Simply put, biodiversity net gain (BNG) ensures that biodiversity is left in a better state than before a development began. Currently, the National Planning Policy Framework requires development to simply achieve a gain. The Environment Act sets out the intention to legislate for a mandatory minimum of 10 per cent of BNG, which is scheduled to come into force in Autumn 2023.

Permitted development is likely to be excluded, however, all other developments will be required to demonstrably achieve a 10 per cent net gain, from small sites through to national infrastructure projects.

For the wider built environment, this will mean in the long-term, a more biodiversity-rich environment where development encourages nature. In the short term, this will require architects, ecologists, and landscape architects to ensure their plans incorporate features that provide food, shelter, and space that benefit both wildlife and people.

What are the stages/processes involved in assessing biodiversity net gain and who can/should undertake them?

It is a process that surveys habitats present on a site before clearance and/or construction work commences. Through the input of the data collected into the biodiversity metric, a measurement of the biodiversity present is determined and represented as ‘Biodiversity Units’.

Each Biodiversity Unit has a financial value ascribed to it. For the first time, biodiversity will be valued easily in monetary terms, a language we can all understand.

To demonstrate whether a development will achieve a net gain for biodiversity on a site, a comparison is made between the pre-development site and the post-development site with the gain or loss illustrated as a percentage.

The biodiversity survey and assessment are undertaken by suitably experienced ecologists but there is a requirement for architects and landscape architects to work more closely to ensure that the right habitats can be retained, enhanced, and created on developments.

What can be done in cases where biodiversity net gain calculations indicate a loss or only very low gains?

If a development does not achieve a net gain, then the BNG should be provided offsite, but within the same local planning authority. These offsite ‘gain sites’ will need to be registered and provide biodiversity units of the same habitat type, or better, to developments that cannot achieve a 10 per cent gain on their own sites.

If you cannot achieve BNG on or off site, then a statutory credit scheme will be available whereby Biodiversity Units can be purchased from the Government. But these will be set at a high price to incentivise improvements to deliver biodiversity locally.

What is a Construction Ecological Management Plan (CEcMP)? When is it needed? And how does it work in practice?

A Construction Ecological Management Plan (CEcMP) sits alongside the more traditional Construction Environmental Management Plan (CEMP) and sets out the measures required to avoid negatively impacting protected/priority species or habitats during site clearance and construction works.

Often conditioned through planning approval, it is required when a site has been shown to contain important, rare, or protected wildlife or their habitats. It sets out the legal protection for each species and habitat likely to be encountered and provides a series of method statements to ensure legal compliance.

What is nutrient neutrality and how does it impact developers and architects?

Nutrient neutrality is defined as “a means of ensuring that development does not add to existing nutrient (nitrogen and/or phosphorus) burdens to the surrounding water environment”.

Natural England has now advised that no planning consents should be granted within a number of river catchment areas with highly protected and sensitive protected habitats unless new developments can demonstrate ‘nutrient neutrality’. These include areas such as The Solent, Camel Valley in Cornwall, parts of Norfolk, and The Lake District, alongside a significant part of the north east of England.

Going forward, all developments which result in a net increase in population served by a wastewater system will need to be demonstrably nutrient neutral to be granted planning approval.

Each catchment area uses a bespoke calculator to measure the nutrient load of a proposed development and this will need to be reduced to zero. To achieve this, a range of nature-based solutions, such as reedbeds, SuDS, swales, and woodland planting amongst others, are required to absorb the excess nutrients. Such features will need to be designed into a proposed development by architects, drainage consultants, and developers.

What are the best practical ways to boost biodiversity on urban development sites?

Green roofs, green walls, vegetated gardens, and rain gardens are all great options. Ensuring that pollen-rich plants can be incorporated into landscaping designs and creating green spaces that are seeded with wildflower mixes (that are mown infrequently) will also enable flowers and grasses to thrive.

The British Standard 8683 Process for designing and implementing BNG has some great pointers.

What about for rural sites where biodiversity is presumably in greater abundance?

Rural sites don’t always have a higher biodiversity value. Often brownfield sites in urban areas have much greater diversity because they remain largely unmanaged for many years. However, for rural sites the principles for retaining, enhancing, and creating good-quality habitats are the same, you just usually have more space to work with.

How important is post-construction evaluation and management with regard to biodiversity? And what practical measures should be put in place?

BNG requires you to proactively manage and monitor any habitats enhanced and created for a minimum of 30 years. Therefore, a biodiversity management and monitoring plan will be required to ensure that you provide what you promise alongside a schedule of monitoring visits by a qualified ecologist for the ensuing 30 years.

Looking ahead, what do you see as the biggest challenges for improving biodiversity within the built environment over the next 10-15 years?

Space. We need enough space for wildlife and people to live and thrive together. This will require us to be able to use as much of the built environment as possible for habitat creation. The bee bus stops in Leicester are a great example of this.

I would love to see a planning regime that requires green or biodiversity roofs and rain gardens to be incorporated into all new builds and developments. My personal hope is that the BNG requirement will allow people to have more contact with nature and appreciate its intrinsic value wherever they live.

For further information visit www.biodiverseconsulting.co.uk