Home » Articles » Environmental Law » Biodiversity Net Gain | The legal framework and what it means for land developers

Biodiversity Net Gain | The legal framework and what it means for land developers

In the UK government’s 25-year Environment Plan (A Green Future: Our 25 Year Plan to Improve the Environment), published in 2018, there was an acknowledgement that biodiversity in the UK had declined, and it was important to allow nature to rebuild. The paper referred (page 32) to the ‘environmental net gain’ principle for development and considered whether it should be mandatory to require ‘environmental net gains’ as part of the planning process.

Following consultation, the government decided that it would make it a legal requirement for all development in England to have such a ‘net gain’, although the terminology is now ‘biodiversity net gain.’

The legal framework is set out in sections 98-101 of the Environment Act 2021, which details the general aims, and also through Schedule 14 of the Environment Act which incorporates the provisions into the Town and Country Planning Act 1990.

The legislation on this is due to come into effect in November 2023 – but many local authorities are already requiring new developments to meet biodiversity net gain criteria, and these are usually processed through S.106 agreements.

Once the legislation is operational then all developers will have to assess the pre-development biodiversity value. This is to be calculated through a biodiversity metric which is produced by Natural England. Once this has been calculated, the developer will need to prepare a biodiversity net gain plan which must demonstrate that the site will have a biodiversity gain of at least 10% following development – again by reference to the metric produced by Natural England. This net gain plan must then be sent to the Local Planning Authority. They will only sign off the development if the biodiversity net gain plan has been approved.

The starting point for a developer is to see if the 10 % gain can be achieved on site. To do this the input of an ecologist is likely to be required so that the site can be properly designed, and that requirement met. For example, if there was a housing development then a good proportion of the site might be established as a wildflower meadow which would score highly in the metric.

But the government recognised that often it would not be possible or practicable for developers to increase the biodiversity on the actual development site. In those circumstances then the developer can buy biodiversity units created off site. Landowners are already looking at this as a way to generate large sums of money by entering into conservation covenants, whereby they covenant to increase the biodiversity of their land in return for a payment from the developer. These covenants will be on the public register and will last for at least 30 years.

In addition, if the developer is not able to find a landowner locally, they will be able to purchase Biodiversity Credits from a national scheme to be set up.

In this way there will be a trade in biodiversity units which will have a market value. The expectation is that this will ensure that the habitat status of land across England generally improves and so we should see a reversal of the steady decline of biodiversity that has fallen steadily over recent decades.

There are a few initial observations to make.

The most authoritative record on UK biodiversity is the State of Nature report 2019 produced by RSPB and other conservation NGOs. This found that the abundance and distribution of UK species had generally declined, with 15 % of UK species threatened with extinction. The UK has been described as being “among the most nature-depleted countries in the world” and is reported to have lost 97% of our wildflower meadows and hedgehogs since the World War II, and over half of our farmland bird populations in the last five decades. The reasons for this are many and complex and include agricultural management, climate change, invasive species and pollution. The government is using different policies to address some of these, but it may be very difficult to assess the overall success of biodiversity net gain against the overall national picture.  

The legislation and the scheme will only apply to England – not to the rest of the UK. In Wales there is already legislation that requires developments to provide a net benefit for biodiversity. The Welsh government will be publishing a biodiversity net gain in 2023 as part of its Nature Recovery Action Plan. Scotland is taking a different approach and looking to generally further biodiversity through its national planning framework (NPF).

The Lawton Review of 2010, Making Space for Nature, was one of the most important papers in the last 20 years to see how England’s wildlife could be improved. The report called for ‘more, bigger, better and joined spaces for nature.’ We will have to see how successful biodiversity net gain is in helping to achieve the aims of that report. Nature needs connectivity, and isolated areas of improved habitat may only play a limited function in really increasing biodiversity.

It is also unclear how the scheme will be enforced, especially in relation to gains made on site. Where the developer is buying biodiversity credits then, as noted above, this will all be documented in a conservation covenant that will last for at least 30 years and the expectation is that landowners would work to meet those commitments. However, where the gains are to be made on site then there will be no such covenant – just the planning condition that requires the net gain minimum of 10% is met and that this habitat is secured for at least 30 years.

Will there be a requirement on the landowner to submit periodic statements on how the biodiversity status is progressing? And what happens if the planned gain does not materialise? This could be especially concerning as climate change takes hold and the habitat does not develop, or may potentially experience drought or wildfires. Or it could be that invasive species prevent the natural evolution of the habitat. It is doubtless there will be many challenges ahead and it is to be hoped that the legislation is implemented in a practical way to achieve its overall aims and if necessary can be modified.

In the past the UK’s biodiversity has always come second to economic pressures and so it has been in steady decline for many decades. The need for change is urgent. It is hoped that the new legislation on biodiversity net gain is an important step in the right direction.