The big question: What are the greatest barriers to biodiversity net gain working in practice?

Three professionals discuss our September big question. 

Tom Butterworth 

Biodiversity technical director, WSP

“The lack of resources within local authorities  is significant” 

Biodiversity net gain is a new method for assessing change in biodiversity, and a relatively new requirement for development. As a result, there are bound to be teething problems. Having said this, I don’t think that there are any barriers – I see them as hurdles to get over, rather than things blocking our way. 

Making biodiversity net gain mandatory for all new developments and standardising the method will create the clarity developers need. We have been told that the government’s Environment Bill and the updated metric from Natural England will resolve these issues.

The lack of resources within local authorities is significant. Biodiversity net gain does not require a huge uplift in time from local authorities, but it does require someone with ecological expertise to check planning applications and oversee delivery. This expertise is needed for existing requirements, but many authorities do not have adequate access. Biodiversity net gain will add to this need.  

Biodiversity net gain can often be delivered within the development site. Where this is not possible, an offset or compensation can be used. At the moment, most local planning authorities do not have a process for identifying and setting up these compensation measures; they need support and, potentially, start-up funding to help set up these processes.


Dr Julia Baker CEnv CIEEM

Writing in a personal capacity

“Social impacts of biodiversity net gain are rarely accounted for”

People are intimately connected with nature and can suffer or benefit from biodiversity net gain. For example, people at a development site could lose a public park and live too far from the biodiversity offset to benefit. Conversely, residents of a development can enjoy enriched natural surroundings when biodiversity net gain is achieved within the housing footprint.

The problem is that the social impacts of biodiversity net gain are rarely accounted for and, when they are, it is not in a comprehensive way that safeguards or enhances wellbeing. We must ensure that protecting and enhancing biodiversity through development ‘does no harm’ to people. This is also an opportunity for infrastructure development to generate long-term benefits for the environment and society.

More than 50% of stakeholders mentioned social justice when asked about biodiversity offsetting as a conservation tool for England, so this is an issue we must address. International principles on the ‘people’ aspects of biodiversity net gain were published in 2018; these include avoiding negative social impacts, and designing, building and maintaining biodiversity net gain in ways that are fair and inclusive for people. There is a working group looking at how these ‘people’ principles can apply within the UK – watch out for updates!


Nick Blyth

Policy and engagement lead, IEMA

“Net gain is not possible if irreplaceable habitats are impacted”

The government is committed to mandate net gains for biodiversity in the Environment Bill. In July, it published a formal response to the consultation, stating, for example, that a 10% net gain will be mandated, with a two-year transition period. There are some welcome points, including recognition of concerns about net gain driving habitat degradation prior to applications and a statement to address this.

Responses to the consultation expressed strong support for protecting irreplaceable habitat and protected sites and species, as well as for the mitigation hierarchy approach. These and many other concerns are all addressed in Biodiversity net gain – Good practice principles for development, developed by IEMA with the Chartered Institute of Ecology and Environmental Management and the Construction Industry Research and Information Association. This guidance is clear concerning claims of net gain and how it is not possible if irreplaceable habitats are impacted.

We anticipate with interest further government proposals on how these and other issues will be addressed, as well as government developments concerning the wider ambition of environmental net gain. What is clear is that professional sustainability and environmental skills will be central to good net gain outcomes.



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