Biodiversity: time to quantify or say goodbye

14th June 2016


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  • Business & Industry ,
  • Built environment ,
  • Planning ,
  • Natural resources ,
  • Biodiversity


Luke Boxall

Assessment of the offsetting pilots reveals that the planning system is not working for biodiversity, writes Jonathan Baker

As management maxims go, ‘you can’t manage what you don’t measure’ is one of the more obvious. Astonishing, then, that this simple rule is not applied to biodiversity in our planning system.

That is not to say that the planning system ignores biodiversity. Look at any local plan, environment statement or planning application and you will be facing a glut of lists, databases, maps and designations. Despite, or perhaps because of, this abundance of information there is little clarity about exactly what biodiversity is being lost and specifically what is being done to mitigate, and, if necessary, compensate for any loss. Providing this information would seem necessary to demonstrate compliance with the ‘net gain’ aspiration for biodiversity, as set out in the National Planning Policy Framework (NPPF).

Practical experience of biodiversity offsetting has been limited in England, as has evidence on its efficacy. To address this, Defra developed a pilot programme in 2012 and commissioned an independent evaluation of the pilots. Six local authority areas were awarded pilot status and they tested tools and processes to feed into the evaluation. This finished in 2014, and Defra published the final report in February (

Panacea or Trojan horse?

One approach that has been considered to contain biodiversity loss is offsetting. As Defra stated in 2013: ‘Biodiversity offsets are conservation activities that are designed to give biodiversity benefits to compensate for losses – ensuring that when a development damages nature (and this damage cannot be avoided) new, bigger or better nature sites will be created.’

Within the UK, biodiversity offsetting has polarised opinion. Some view it as a panacea, others as a neo-liberal Trojan horse. This polarisation is a result of proponents overselling the concept as revolutionary. The truth is that biodiversity offsetting represents an evolution of the existing system, something that is often overlooked.

The 2010 Conservative party general election manifesto introduced biodiversity offsetting, then termed conservation credits, citing their success in the US and Australia. Since then biodiversity offsetting has increased in profile, gaining the avid support of Owen Paterson, Defra secretary of state between 2012 and 2014. He is on record as seeing it as a tool that ‘has the potential to grow the economy and improve our environment at the same time’. His enthusiasm has been mirrored by the Ecosystem Markets taskforce, which, along with others, noted it could provide millions of pounds of investment for nature conservation while potentially streamlining planning processes.

Meanwhile, some conservationists feel it offers a ‘licence to trash’ and fails to recognise the local and implicit value of green spaces.

Offsetting steps

Defra has been building the evidence base and creating a proto-system for offsets. Assessment of the pilots between 2012 and 2014 have fed into this.

Creating a national system of biodiversity offsetting is a complex undertaking but at a project level it can be simplified to a few steps:

  • Defining what biodiversity is at the location.
  • Understanding the total impact of the development, including any mitigation and onsite compensation.
  • Quantifying how much biodiversity will be lost – or gained – from the development.
  • If there is loss, identifying how and where biodiversity could be improved to compensate.
  • Delivery of biodiversity compensation.

Superficially, these steps appear similar to what we do now. But there is one crucial difference: the use of a metric to quantify the net impact. This has been developed by Defra and Natural England since 2010 and has been further refined and adapted through the experiences of the pilots.

At its simplest, the measure defines biodiversity by its extent (hectares), importance (as described in biodiversity action plans) and condition (quality of the habitat). These three values are combined and a single figure is produced ( It is explicit about what is: onsite; being lost; mitigation; and compensation for this loss. If there is a net loss after the onsite mitigation and compensation, the metric specifies the amount and type of biodiversity that needs to be created or improved to compensate. This system is guided by supplementary rules, about what can and cannot be compensated for, the location, type and duration of any offsite compensation.

Although the evidence from the evaluation has nuanced messages on the costs and benefits of offsetting as a whole, it is clear on one thing: that using the metric on all applications and all habitats has huge potential for improving how we manage our natural heritage and our ability to achieve net gains for biodiversity. The reason for this is simple – the metric provides a clear, quantified and transparent message about the biodiversity impact of a development – something currently missing.

Huge underestimation

This is important because evidence collected in the evaluation suggested that just 0.1% of planning applications are required to undertake any form of compensation. This is fine if only 0.1% of developments result in a net loss of biodiversity. In fact, evidence from the pilots suggests biodiversity losses are hugely underestimated and that the metric reveals that most applications have some net impact, which is not consistent with the NPPF’s net gain policy.

To understand why this is the case, it is necessary to review how decisions about biodiversity impacts are made. Understanding the impact of a development involves an impressive weight of evidence about what is onsite and likely to be lost. But in the cacophony of considerations for planners this detailed evidence is often overlooked. This is not just because of the volume of evidence, but its qualitative nature too. Current planning applications involve various parties trading evidence about the impact of the development and whether onsite activities reduce this. Evidence from the pilots found that applications seldom state what is being lost, how that specific loss is being mitigated, what the total impact of a development is or how losses are being compensated. It is difficult for planning officers, who have to consider matters as diverse as sewage management and demands on schools, to form a clear message from these qualified and often conflicting opinions.

A metric to quantify the net impact of biodiversity loss has the potential to improve how we manage our natural heritage

Helping hand

Most of those involved in the pilots felt that the clear message from the metric – that x amount is going to be lost – helped planning officers, ecologists, developers, stakeholders and consultants cut through the mass of information and understand the likely impact of an application. In many instances, the information presented by the metric caused developers to improve their design to reduce onsite impacts, often by increasing onsite mitigation and compensation.

The metric is not perfect. Some participants in the pilots felt it was too simple; others that it was too complex. Using it would incur some cost while users familiarised themselves – although the evidence from the evaluation suggested this would not be substantial. The potential of the metric to streamline planning applications was not thoroughly tested in the pilots but there was evidence it was more efficient than the processes already in use.

How any identified biodiversity impacts are compensated for is not straightforward. But it is clear from the evaluation of the pilots that the current system is deficient and the country is far from achieving net biodiversity gain, which is essential to meet the government’s commitment to leaving the environment in a better condition than it found it.

The evidence from the pilots shows that, if we do not start to quantify biodiversity in our planning applications, we are at risk of losing it.


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