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Addressing the Biodiversity Emergency through Planning

The Biodiversity Net Gain (BNG) Metric 3.1, is but one key tool in achieving ‘authentic’ BNG

Dr Helen Barber is an Associate Director in Blue-Green Infrastructure and Biodiversity Planning at AECOM

The rising prioritisation of biodiversity is epic and necessary

Aiming to leave biodiversity in no worse state (no biodiversity loss) post development, was a planning goal and requirement for decades, but biodiversity was still lost - despite the good intentions and global challenges to ‘halt biodiversity loss by 2010’.

Over the decades, many reports and assessments - such as the Millennium Ecosystem Services Assessment (2005), drew attention to global biodiversity loss and the importance to our own survival. Yet, when the ‘State of Nature’ report in 2019 headlined the decline of almost half of all species since 1970, this seemed to strike a chord in spheres outside of environmental professions - more than before. More recently, The Dasgupta Review (2021): the Economics of Biodiversity, highlighted the UK’s lowly position in global indexes of biodiversity loss, which surprised some. Certainly, the concerted collaborative effort needed by all, to reverse the trend, became ever clearer.

BNG however, is not new. The NPPF asked for it. Yet, despite some good examples, biodiversity was still being lost overall. So, in response to the increasing prioritisation of the biodiversity agenda - most markedly illustrated in 2019 through many governments around the globe declaring a ‘biodiversity emergency’ – the UK being no exception, we had to find new ways to do BNG.

Mastering the art

We used to propose and assess BNG in purely qualitative and subjective ways e.g. relying on LA ecologists, or ecologically astute others, to identify and negotiate what was needed. Yet, what if the LA didn’t have enough ecologically skilled staff, or they didn’t have the additional negotiation skills, or planning nous to ensure the BNG was adequately tied into planning policies, documents, or conditions? Partly, this is where a quantitative and measurable method was needed. Enter the Defra metric calculation tool (currently on version 3.1), and the mandatory minimum 10% BNG set out in the Environment Act (2021) to take effect in 2023. Bringing in quantitative aspects is good and much needed - if not at the sake of the qualitative. Yet, we should remind ourselves  ‘not to throw the baby out with the bathwater’. We need a holistic approach of both qualitative ‘and’ quantitative.

Holistic BNG is a key collaborative practice for increasing wildlife through new built development to address the biodiversity emergency. There is an art to be mastered in balancing quantitative and qualitative aspects. Let us be custodians, not only accountants to biodiversity. For instance, by: ensuring connectivity, limiting human related disturbance (e.g. light, noise, and freely roaming pets), providing habitat features and resources, whilst reducing risk (e.g. vehicular strikes).

So, what has more than 20+ years of professional work, lots of research, and collaborations taught me?


  • Awareness of Emerging Processes – keep an eye out for a likely revision to BS 8683, government guidance, and secondary legislation updates, and plan accordingly. Regular reviews over ways of working will be needed over the next couple of years.
  • Gearing up industry – adjust project management programs and ensure staff are trained and developed (all professions need training and ecologists need UK Hab training and possibly enhanced botanical ID skills). Let’s resource BNG Don’t make the mistake of placing it at the end of the project management chain - only to later find out it was your most important priority. BNG is often an iterative process, so involve at the start.
  • Ensure accuracy – drawings and plans. GIS specialists are our friends, let’s give them time to close those polygons and let them gain clean drawings from civils or landscape colleagues.
  • Stimulating and encouraging emerging green markets and partnerships g. to supply habitat units in a wider environmentally responsive way, connected to blue-green infrastructure and balance human versus nature conflicts and opportunities.
  • Don’t reinvent the wheel with So much good guidance is out there. Find and link to it.
  • Multifunctional benefits and ‘saving 2 birds with one nest’ [yes, I have gone all PC in re-jigging ancient proverbs].
  • Be brave and push the boundaries for biodiversity.

Dr Helen Barber holds a doctorate in biodiversity planning. She is a Chartered Town Planner and former Chartered Landscape Architect. She has worked for local authorities, a government agency, university, and consultancies. She joined AECOM in January as an Associate Director in Blue-Green Infrastructure and Biodiversity Planning. Prior to this, she sat on a local government BNG Advisory Panel for PAS (Planning and Advisory Service)

For the RTPI's own views on Biodiversity Net Gain, see the RTPI's response to DEFRA Biodiversity Net Gain Regulations and Implementation consultation and the ABC of BNG in the Planner magazine.

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