An insider’s guide to mainstreaming Biodiversity Net Gain

by Dr Julia Baker, Biodiversity Technical Specialist, Balfour Beatty

Fixing a faulty system

The challenge to balance economic growth with measures to protect and enhance nature has never been more urgent, given the unprecedented investment in infrastructure and the increasing decline in biodiversity. However in many countries, laws and polices allow infrastructure projects to proceed with biodiversity loss. Here projects are subject to Environmental Impact Assessments, planning conditions and other consents – but none make it an absolute requirement that there will be no overall loss of biodiversity, or even a net gain. So losses of biodiversity from infrastructure projects are not because developers run riot, but from a faulty consent system that needs fixing.

The principle of delivering a net gain for biodiversity can be that fix. By considering upfront how infrastructure projects can boost biodiversity, we can overcome the current ‘development versus nature’ scenario and ensure that our infrastructure projects support the UK Government to deliver its priorities for biodiversity.

Put at its most simple, Biodiversity Net Gain is when development leaves biodiversity in a better state than before.

It is not development that takes a ‘numbers-focused’ approach to only outweigh losses of biodiversity with gains. It is development that follows the mitigation hierarchy and achieves net gains in biodiversity, through additional conservation activities, that contribute towards strategic priorities for biodiversity conservation.

These strategic priorities can be at local, regional and national levels. They are often set by governments and conservation organisations, and represent the most urgent (e.g. addressing declines in critically endangered species) and the most desired (e.g. landscape-level planning for ecological networks) actions.

In practice this means that development seeking to achieve Biodiversity Net Gain will, for example, help boost threatened species or enhance natural connectivity – where these strategic priorities are commensurable to the losses of biodiversity it incurs, and additional to what would have happened without the development.

The mitigation hierarchy is a sequential process that underpins environmental impact assessments. The first step is for development to avoid negative impacts on biodiversity, then secondly to minimise these impacts. Where avoidance and minimisation are not feasible, the third step is to remediate on-site damage. The final step is to compensate for unavoidable residual loss of biodiversity either on-site, or by creating or enhancing biodiversity elsewhere (i.e. through biodiversity offsets).

Common lizard, protected under the Wildlife and Countryside Act 1981 (Dave Rogers)
Common lizard, protected under the Wildlife and Countryside Act 1981 (Dave Rogers).

Moving ahead in the UK

Governments, investors and businesses worldwide are applying policies for development to achieve ‘No Net Loss’ (NNL) of biodiversity. Some focus on biodiversity offsetting, which is a shame because instead of focusing on the outcome we want to achieve (development with no overall loss of nature), they focus on one method to get there.

It’s different in the UK, as the focus is firmly on Biodiversity Net Gain. It’s also an exciting time because this concept is fast gaining traction within industry for two main reasons:

Firstly, business works in numbers. The likes of carbon, waste and other sustainability factors dominate corporate sustainability strategies because they have metrics that businesses use to set targets and measure progress. This changed in 2012 when the UK government issued a ‘biodiversity unit’ metric, enabling us to set net gain targets and use numbers as a communication tool within executive boardrooms.

Secondly, there’s a common belief within industry that preserving biodiversity costs money and doesn’t generate cash in return. That’s the opposite of carbon or waste for example, where it’s easy to see how ‘sustainability’ actions can save money. But there’s growing recognition that enhancing biodiversity enhances the development itself, leaving a positive legacy that goes beyond building a new road or housing estate.

Now major commissioning agencies within the UK’s housing, transport and energy sectors have committed to, or are calling for, Biodiversity Net Gain. For example:

Several local authorities have also adopted Biodiversity Net Gain. For example, Litchfield District Council stipulates a 20% net gain in biodiversity for development proposals that pose a risk to key ecological features, and Dorset County Council applies a biodiversity net gain requirement to developments over 0.1ha.

Adding to this momentum are three recent major advances:

In 2016, professional environmental institutes published the UK’s first good practice principles on Biodiversity Net Gain.

In January 2018, the Government’s 25-year Environment Plan cited that:

The Government will embed an ‘environmental net gain’ principle for development, including housing and infrastructure.

Our immediate ambition is to work in partnership with other Government bodies, local planning authorities and developers to mainstream the use of existing biodiversity net gain approaches within the planning system, update the tools that underpin them and reduce process costs on developers

Finally, the current consultation on the National Planning Policy Framework talks about “securing measurable net gains for biodiversity”.

Landscaping for a highways improvement scheme (Sam Bower)
Landscaping for a highways improvement scheme (Sam Bower).

An insider’s guide

All of these efforts put Biodiversity Net Gain on political and commercial agendas. But in practice, Biodiversity Net Gain developments are too few and far between given the volume of infrastructure projects being built and in the pipeline. I work for one of the UK’s largest contractors, Balfour Beatty. We build infrastructure that includes transport, energy, housing and hospitals. Based on my first-hand experience with decision-making throughout the lifecycle of a development project, I think we need to do the following to mainstream Biodiversity Net Gain:

  1. Establish a robust metric and be clear how it is used

A robust metric to measure Biodiversity Net Gain is critical. The government’s ‘biodiversity unit’ metric was a good start, but it’s six years since it was introduced and we need to address the metric’s flaws. We welcome Natural England’s commitment to update the metric, although this seems to be in incremental phases whereas we need a fully comprehensive overhaul.

Along with a robust metric is the need to produce clear guidance on good practice when using metrics. This is to avoid a numbers-focussed approach where Biodiversity Net Gain is achieved on paper but means little in practice. For example, a development results in the loss of woodland and achieves Biodiversity Net Gain by enhancing woodland nearby. While the metric shows an increase in biodiversity units, the loss of woodland cover is a significant loss of green space for that locality. Metrics alone should never dictate decision-making. They should be used in combination with rich ecological, qualitative information that capture aspects of biodiversity that the metric does not, such as a site’s ecological functionality, the animals that use it and its position within an ecological network.

  1. Collaborate with local nature conservation experts

Much within the infrastructure industry is based on collaboration. We need to extend this to work with local wildlife experts, as measures to enhance biodiversity are far more likely to succeed if local experts are involved in shaping the solutions.

We also need to work with experts from government, NGOs and academia. In turn this requires all parties to be genuinely willing to engage, a transparency from industry in its application of the mitigation hierarchy and measurement of biodiversity net gain, and a constructive forum where learning can be shared openly without unjustified criticism, perhaps jointly led by industry and NGOs.

  1. Plan at a landscape scale

Infrastructure projects are being built on vast scales, where they cross several local authority boundaries. We need regional planning for Biodiversity Net Gain whereby it is designed and implemented for both individual landscapes and for neighbouring landscapes in combination. We also need to look beyond an individual project’s boundaries to achieve Biodiversity Net Gain ‘as one’ for all projects within a locality.

  1. Quantify the wider economic and social benefits

Investing in Biodiversity Net Gain can deliver multiple benefits including improvements in air quality, climate regulation and recreational benefits. However, these wider benefits are rarely quantified, meaning that decision-makers do not recognise or account for the importance of biodiversity to our society and economy. Applying Natural Capital accounting to losses and gains in biodiversity from infrastructure projects will measure these wider benefits and, where appropriate, identify their monetary value. Doing so significantly changes how biodiversity is perceived and treated within decision-making. For example, an investment of £60k in NNL for a transport upgrade scheme generated £1.4 million in community benefits.

  1. Use biodiversity offsetting carefully

There have been cases of poor practice regarding biodiversity offsetting. But there are cases where offsets achieved more positive outcomes for biodiversity compared with the status quo.

Government and industry must ensure that, if offsetting is required to deliver Biodiversity Net Gain (after strictly following the mitigation hierarchy i.e. only if it cannot be otherwise avoided), it follows good practice, is rigorously monitored, is funded for the long-term and delivers meaningful long-term benefits on the ground for both people and biodiversity. There are international standards on good practice and growing literature on how offsets can generate meaningful long-term benefits. The next step is to make this information useable for industry and to support its implementation.

In summary

We need to rethink our approach to development and biodiversity, especially to resolve the perceived tension between the two and have conversations about actual problems, rather than remain stuck in the simplistic idea of “development drives biodiversity loss”.

Biodiversity Net Gain can be the solution, but current efforts while admirable are patchy, inconsistent and ad-hoc. We need the approach to become routine from the outset, where developers engage stakeholders to plan how to improve biodiversity. This is a bold step-change from the current consent process for development, but one that is needed if infrastructure projects are to generate long-term benefits for nature, people and the economy.


The unprecedented investment in infrastructure: see the State of Biodiversity Mitigation 2017, Forest Trends

Global inventory of biodiversity offset policies:

The Mitigation Hierarchy: for more information, see ’10 principles for applying the mitigation hierarchy’ by the Nature Conservancy, and the Mitigation Hierarchy by the Business and Biodiversity Offset Programme (BBOP).

The UK government’s biodiversity unit’ metric.

Enhancing biodiversity can enhance a development itself, for example see Natural England’s guide on the benefits of investing in the natural environment

The Government’s 25-year Environment Plan.

The current consultation on the National Planning Policy Framework.

Evaluation of the government’s ‘biodiversity unit’ metric, see Evaluation of the Biodiversity Offsetting pilot programme by Collingwood Environmental, 2014).

Example of where local wildlife experts were involved in achieving Biodiversity Net Gain for an infrastructure project: the partnership between The Thameslink Programme and London Wildlife Trust resulted in a project that achieved Biodiversity Net Gain for Thameslink in a way that helped to restore the Great North Wood.

Also the Greater Western modernisation railway project extends from Maidenhead just outside London across the country to Cardiff, and is working with local partners to achieve No Net Loss of Biodiversity.

For an example of a natural capital account of NNL for a transport upgrade scheme, see:

For examples of biodiversity offsets, such as the case studies in BBOP’s webinar series.

International standards on good practice, for example BBOP’s Standard on Biodiversity Offsets.

Literature on how offsets can generate meaningful long-term benefits, for example IUCN’s technical conditions for positive outcomes from biodiversity offsets.