How can built development leave the natural environment in a better shape than it was before? This is the question at the heart of Defra’s recent consultation on ‘biodiversity net gain’.

We know from the State of Nature 2016 report that although agricultural intensification has the biggest impact on wildlife, habitat loss caused by increased urbanisation is one of the top ten drivers of biodiversity change. So the RSPB gives great importance to ensuring that planning systems and policies across the UK protect the environment and promote development that is truly sustainable – an approach that we know is feasible through our partnership with Barratt Developments to build new communities, providing homes for people and wildlife.

That’s why we welcome Defra’s proposals for biodiversity net gain in England. These proposals follow on from the Government’s commitment in the 25 Year Environment Plan to “improve England’s environment and to become the first generation to leave the natural environment in a better state than we found it”, and their long-term commitment to develop and deliver a Nature Recovery Network that will protect and restore threatened wildlife and habitats.

By changing how development treats the natural world, a system of biodiversity net gain could make a significant contribution to the Nature Recovery Network, as well as benefiting local communities through access to wildlife-rich greenspace. It will be especially important in places like the Oxford-Cambridge Arc (which includes RSPB reserves such as Otmoor, The Lodge and Fen Drayton, as well as our flagship housing project with Barratt of Kingsbrook, Aylesbury) where there are ambitions to build an additional million new homes by 2050.

Image: RSPB Otmoor lies within the Oxford-Cambridge Arc. Photo credit: Eleanor Bentall (

However, any system of biodiversity net gain has risks as well as opportunities, and as Defra’s consultation shows, there’s still a lot of technical detail to work through.

Here are some headlines from our response to the consultation.


For the maximum benefit, it’s important to draw the scope of the policy broadly. That means not just housing, but commercial and other development too, as well as nationally significant infrastructure projects. Exemptions need to be few (for example, householder and permitted development) as we need to deal with cumulative biodiversity losses from small-scale development. We should not apply a net gain approach to protected sites to which more robust regulations already apply, or to irreplaceable habitats where the loss could not be compensated. Finally, we should always rigorously apply the mitigation hierarchy so that all efforts are made to avoid and mitigate environmental harm in the first instance, only compensating impacts on habitats and species as a last resort.


Defra proposes a 10% net gain requirement (ie 10% more than what is required to simply compensate for loss, by area), but we believe that won’t be enough to meet the Government’s ambitions. Using the figures in the Government’s own impact assessment, the £63.8 million annual net spending that would be generated from development would deliver less than 8% of the 500,000 ha Nature Recovery Network (NRN) target. Given that net gain is anticipated to be an important source of funding for delivery of the NRN, this is nowhere near enough.

Statutory underpinning

We believe that a biodiversity net gain requirement should be underpinned by regulation and linked to clear statutory targets for protecting and restoring biodiversity through the proposed Westminster Environment Bill. This would provide a level playing field for businesses and would help to ensure the effective and efficient targeting of resources.

Spatial mapping

Nature’s recovery must be planned and delivered as part of the statutory planning process. ‘Nature recovery maps’ that can be embedded into existing local plans will ensure that financial contributions from developers are spent in a way that puts nature at the heart of decision-making, and provide a clear link between spending decisions for biodiversity net gain and delivery of the Nature Recovery Network.

The ‘Defra metric’

Defra, working with Natural England, has developed a metric to measure ‘biodiversity units’. We believe a number of changes are needed to prevent some habitats being unreasonably favoured over others, and to address the fact that the current version of the metric does not include the impact on species, or the cumulative or indirect impacts of development. We would expect stakeholders such as ourselves to be closely involved in any process to review and update the metric.

The tariff

Defra proposes that in some circumstances, developers will simply pay a tariff to fund habitat creation. Overall we support this approach, although setting the right tariff levels will be critical, as there is a risk that the proposed rates may provide a strong incentive for developers to avoid the tariff and commission rapidly-established habitats that may not meet local or national priorities. We welcome mechanisms for reviewing tariffs and the option of local flexibility.


New habitats created through a system of net gain need to be protected in the long-term, in order that they can be enjoyed by future generations, and secure nature’s recovery for decades to come. We suggest these sites should be secured in perpetuity through, for example, the use of planning conditions or obligations, conservation covenants or other management agreements. A clear and agreed understanding of what is meant by ‘in perpetuity’ is also required, ideally for the lifetime of the development.

Let me know what you think. For further details about our response, please contact