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Biodiversity Net Gain

Faircharm Creative Quarter - Image by Tibbalds

Can Biodiversity Net Gain lead to higher quality development?

Biodiversity Net Gain should be viewed as powerful tool to promote holistic development design, rather than another ecological planning hurdle, according to engineers WSP.

Biodiversity Net Gain (BNG) is the principle that all future development and infrastructure projects must leave the site ‘measurably’ better for biodiversity than before. The minimum statutory improvement under the 2021 Environment Act is an additional 10% above a site’s existing baseline, meaning that 110% BNG must finally be achieved, whether on a brownfield or greenfield site. Its legality has already been upheld at appeal so BNG is here to stay, with some local planning authorities already raising the bar to 20% increased biodiversity because of the severity of the climate crisis.  

The BNG measuring tool, currently Metric 3.0, measures nature losses and gains, using a set range of ecological criteria. It was described by workshop leaders Tom Butterworth and Jonny Miller of WSP as ‘crude’ because it doesn’t include all biodiversity, and converts complex, living places into unit numbers, but they were also of the opinion that the legislative mechanism is robust enough to bring about more nature-friendly integrated design.   

The consequences of enforced BNG are interesting and complex. It means that the need of a developer for a financially viable site has to be balanced with a local authority’s requirement to follow legislation and landscape protection.  An engineer’s demand for space for services has to be looked at alongside a community’s right to green space. And we landscape architects want functionality, landscape character and good placemaking. The process demands multi-functional solutions, creative thinking and compromises until the numbers stack up.

Inevitably, not all sites can achieve their 110% net gain, and some will be permitted to pay to offset their obligations to other registered sites. The desire to keep funds local has motivated nature organisations and local authorities to map their existing regional Green and Blue Infrastructure networks (e.g. woodland, hedgerows and waterways) so that they have evidence of the gaps that could be improved.

Butterworth and Miller believe that BNG is an opportunity for a genuinely innovative design process, in which many benefits can be overlayed in the same space. To achieve such collaboration, they are calling for a new language of ‘respectful communication’ from all stakeholders which values others’ opinions and works towards an acceptable and beneficial outcome for all parties. 

The workshop was the first in a series of three by Design West and the Landscape Institute. For more information see

Georgina Harvey

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Georgina Harvey

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