Many thanks to Dr Matt Cowley from EAD Ecology, who has provided the below. Matt Cowley is a Design Review Panel member, attending Design Review Panels across the South West; in Cornwall, Devon (both Plymouth and Exeter), Somerset, Dorset, Wiltshire and Swindon. For more information on Matt Cowley please click here ...

In the Spring Statement 2019, the Chancellor announced that under the Government’s forthcoming Environment Bill it would become mandatory for new development to deliver a net gain in biodiversity. This blog article considers the detail behind this announcement and its implications for planning and design.

Biodiversity can be a confusing term, but essentially it refers to the diversity of plant and animal life - ‘wildlife’ in its broadest sense. On the face of it then, legislation that obliges developers to increase biodiversity, whilst at the same time providing housing or infrastructure (with its inherent land-take) sounds like a tall order and perhaps a radical step for a government perceived to have a pro-development agenda.

However, given the direction of recent Government policy, rather than a radical departure, mandating net gain appears to be a logical next step. In January 2018, the Government published its 25 Year Plan to improve the environment[1]. The Government’s stated ambition was to leave the environment in a better state than they found it. This ambition was not considered incompatible with other stated Government objectives such as improving infrastructure, promoting economic growth and addressing the shortage of housing. The Government pledged to support development and the environment by embedding the principle of net gain within the planning system.

Environment Minister, Michael Gove: “Population growth and economic development will mean more demand for housing and this Government is committed to building many more homes. However, we will ensure that we support development and the environment by embedding the principle that new development should result in net environmental gain – with neglected or degraded land returned to health and habitats for wildlife restored or created”.

A key policy step towards embedding this principle came in July 2018 with the publication of the Revised National Planning Policy Framework (NPPF). This stated: ‘Planning policies and decisions should contribute to and enhance the natural and local environment by minimising impacts and providing net gains for biodiversity’[1]. This strengthened the requirement for net gain relative to the previous NPPF, which included the significant caveat that net gain for biodiversity should be provided ‘where possible’. Even before the Environment Bill becomes law, there is a strong planning policy driver for net biodiversity gain.

Measuring biodiversity

The Revised NPPF refers to net biodiversity gain that is measurable. The obvious implication is that biodiversity losses and gains should be quantified and presented with a planning application to inform the decision-making process. It is no coincidence that Defra’s ‘Biodiversity Offset Metric’ will shortly be reissued (‘Defra Metric 2.0’). This is a spreadsheet-based metric that converts biodiversity into a single unit of measurement, a ‘biodiversity unit’. In essence, what is meant by development that provides a net biodiversity gain is development that provides a net gain in biodiversity units, as calculated by the Defra metric.