Biodiversity – gaining ground?

Introduction

On 9 November 2021, England became the world's first jurisdiction to adopt legislation requiring biodiversity net gain to be provided as part of the planning approval process for buildings and major infrastructure projects. The emerging policies and tools supporting the new biodiversity net gain legislation are the result of a decade of pilot testing, consultation and refinement, involving central and local government, environmental NGOs, researchers, professional bodies and the private sector.

Originally intended as a policy tool for expanding ecological networks, net gain has instead developed into a standalone policy focused on mitigating localised effects of development. We argue that a less narrowly localised approach to net gain would go further towards delivering the government's vision of ‘bigger, better and more joined up places for nature.’ Successful implementation will require training for ecologists, planners, developers, architects and landscape architects to avoid resourcing bottlenecks and delays in planning approvals.

Background

According to the Biodiversity Intactness Index, ¹ the UK is the 12th most ecologically depleted country in the world, retaining only 42% of its native species diversity and abundance. England is even more ecologically depleted than the UK as a whole, primarily due to agriculture, urban growth and past deforestation. England's statutorily protected landscapes ² are a product of traditional agriculture, rather than remnants of intact wilderness. In this cultural context, enhancing biodiversity typically means reinstating traditional pre-industrial land management techniques, including hedge maintenance and carefully monitored grazing, rather than simply letting nature take its course.

Policy statements

In 2010, the UK government commissioned an independent review of England's wildlife sites by ecologist Professor Sir John Lawton, ³ which concluded that ‘England's collection of wildlife areas is fragmented and does not represent a coherent and resilient ecological network capable of responding to the challenges of climate change and other pressures.’ ⁴ The report recommended that wildlife sites should be better managed, larger, more numerous and better connected. The report also suggested that habitat creation could be funded through biodiversity offsets, setting out a series of guiding principles and recommending that these should be tested through pilot schemes.

Responding in the 2011 White Paper on the natural environment, ⁵ and the Biodiversity 2020 strategy, ⁶ the government outlined an ambition to ‘move from net biodiversity loss to net gain, by supporting healthy, well-functioning ecosystems and coherent ecological networks.’ ⁷ This strategy included establishing more Local Nature Partnerships, creating Nature Improvement Areas, improving the planning system to deliver ‘a more strategic and integrated approach to planning for nature’ ⁸ within the planning system, and using biodiversity offsets ‘to expand and restore the ecological network in England.’ ⁹ The White Paper indicated that biodiversity net gain would be delivered by local authority decision makers as part of the planning process.

The White Paper envisaged that net gain would be a policy tool as part of an overarching vision ‘to halt overall biodiversity loss, support healthy well-functioning ecosystems and establish coherent ecological networks, with more and better places for nature for the benefit of wildlife and people.’ ¹⁰ However, in our view over the following decade net gain evolved into a standalone policy with minimal contribution to the overarching vision of establishing ecological networks.

In 2017, the government published its 25 Year Environmental Plan, which stated that ‘the planning system should provide biodiversity net gains where possible’ ¹¹ while setting out separate plans for a Nature Recovery Network. Thus, biodiversity net gain and ecological networks diverged in two separate policy strands, which have yet to be joined back together. In January 2020 the government published the first draft of the Environment Bill, ¹² which set out separate unconnected provisions for biodiversity net gain and local nature recovery strategies.

The new legislation

The Environment Act 2021 (‘the Environment Act’) will require ¹³ all planning applications in England to demonstrate 10% net increase in biodiversity (‘biodiversity net gain’), using a calculation metric developed by Defra. ¹⁴ Part of the net gain can be delivered off-site, either by the developer, the local authority or another provider. There will also be a national scheme for biodiversity credits, priced at a level which would avoid discouraging other potential offset providers.

Where net gain is provided by the developer (whether on or off site) or another provider, they will have to enter into a long-term agreement which runs with the land, known as a ‘conservation covenant’. This contains an obligation to manage the land for biodiversity for at least 30 years, with monitoring to be undertaken by a ‘responsible body’ (like a public body or conservation charity).

Local authorities will have the option of providing the biodiversity offsets as part of a s.106 agreement. This is a commonly used mechanism to levy a contribution from the developer, which is ringfenced and spent by the local authority to offset various local impacts of a development.

The Environment Act makes provision for a central register of biodiversity offsets, to avoid double counting. The government envisages that a market for biodiversity units will emerge, potentially worth up to £800 m per year in England, assuming 25% of biodiversity gains are provided offsite. ¹⁵

The Environment Act also requires Defra to appoint local authorities to create local nature recovery strategies, setting out strategies and opportunities for enhancing biodiversity. According to the legislation, local nature recovery strategies could be created at county or metropolitan level, spanning across several local authorities. The Environment Act does not explicitly link biodiversity net gain provisions to local nature recovery strategies.

Implementation of biodiversity Net gain policies

In 2012, Defra published a first draft of its Biodiversity Metric, which was used for pilot offsetting schemes set up in six local authority areas. ¹⁶ The Biodiversity Metric was revised in 2019 and 2021.

In 2016, a working group of ecology professionals published a best practice guide to biodiversity net gain, ¹⁷ which was expanded ¹⁸ in 2019. A British Standard for implementing biodiversity net gain was published in 2021. ¹⁹

In 2018, the National Planning Policy Framework was amended to mention biodiversity net gain. ²⁰ By the end of 2020, 66% of local authorities had included net gain policies in current or draft local plans, and 37 local authorities had made no net loss or net gain mandatory for all planning applications. ²¹ There are still therefore many local authorities who have yet to incorporate net gain policies into their local plans.

Implementation of ecological networks

Efforts to create larger and more coherent environmental networks seem to have progressed at a slower pace. Beginning in 2012, Local Nature Partnerships were set up at county level covering most of England, ²² and Defra provided funding for 12 large scale Nature Improvement Areas from 2012 to 2015. ²³ Unfortunately little progress was made in developing these policies over the next five years.

In 2020, Defra and Natural England announced its ambition to create a Nature Recovery Network, supported by a cross sectoral delivery partnership. ²⁴ Natural England produced digital maps showing how England's priority habitats could be extended to form ecological networks, ²⁵ and Defra selected five local authorities ²⁶ to pioneer Local Nature Recovery Strategies, ²⁷ augmenting the national habitat network maps with locally held information. The Environment Act now requires local planning authorities to create local nature recovery strategies, but the required content, procedure and timeline has yet to be clarified in secondary legislation. ²⁸ Therefore, the process of preparing local nature recovery strategies has not yet begun.

Are we achieving ‘bigger, better and more joined up places for nature’?

In their current form, biodiversity net gain and local nature recovery strategies are only loosely connected. In other words, the implementation of net gain does not reflect the joined-up vision set out in the strategies set out a decade ago. After analysing the outcomes from six local planning authorities who have already adopted net gain, researchers found that 95% of biodiversity gains were provided on or near development sites, compared to only 4.5% of gains provided off-site, ²⁹ limiting the scope for expanding ecological networks. The reasons for this include safeguards embedded in the metric and best practice policies, which will be explained further below.

Scoring biodiversity

The Defra Biodiversity Metric works by comparing pre-development and proposed post-development biodiversity scores, seeking to achieve a 10% net gain. To arrive at a score, various multipliers are used. The first version of Defra's Biodiversity Metric ³⁰ strongly prioritised ecological networks, with offsets located in designated ecological networks scoring three times higher than offsets outside such areas. In the second version of the metric ³¹ habitat enhancement within a designated ecological network only scored 15% higher (‘spatial risk multiplier'), with a further 10% ‘connectivity multiplier' based on geographic proximity to existing habitats. However, a new ‘spatial risk multiplier' heavily penalised scores for habitats created in neighbouring or more distant local planning authorities. The third version of the metric ³² dropped the connectivity multiplier but retained the strategic significance and spatial risk multipliers.

In our opinion, the above substitution of political geography for ecological networks is unsatisfactory for three reasons. First, local nature recovery strategies may span across several local authorities, including metropolitan areas, but the metric effectively truncates these at local authority boundaries. Second, local planning authorities vary enormously in size, from 3 km² (City of London) to over 4,000 km² (Northumberland). Third, some areas have two-tier authorities where planning decisions relating to minerals, waste and transport are taken at a county level, with most other planning decisions taken at district level. In two-tier authorities a habitat gain in the same county but an adjoining district would score lower in district level planning applications.

The third version of the biodiversity metric provides an option of using National Character Areas instead of local planning authorities as the geographic basis of the spatial risk multiplier. National Character Areas, as defined by Natural England, are a subdivision of England based on a combination of landscape, biodiversity, geodiversity and economic activity. ³³ In our view, this is a step in the right direction, but we are concerned that local planning authorities could choose to disapply this option in favour of political geography.

Mitigation hierarchy

Both the Biodiversity Metrics and best practice guidance ³⁴ contain safeguards based on principles recommended in the Lawton Report, the first of which was:

“(i) Biodiversity offsetting must not become a ‘licence to destroy’ or damage existing habitat of recognised value. In other words, offsets must only be used to compensate for genuinely unavoidable damage. Development should avoid adverse impacts first, mitigate impacts second and compensate for unavoidable impacts as a last resort”. ³⁵

This first principle set out above, is embedded in the following safeguards:

The Biodiversity Metric cannot be used to compensate for loss of high distinctiveness habitats. Where such a loss is unavoidable, bespoke compensation must be agreed.

Development involves construction works during which much on-site habitat is lost, at least temporarily. Prioritising habitat gains on site means these losses are compensated by uncertain future gains. By contrast the Lawton Report recommended that ‘[w]herever possible, the created habitat should be in place before the original site is lost.’ ³⁷

Capacity

Currently, an ecological report is only required for planning applications which may affect protected areas or species, or in local authorities which have already adopted biodiversity net gain policies. The new biodiversity net gain legislation will create a greatly increased demand for ecologists, as more private sector ecologists will be needed to undertake habitat surveys, provide calculations and design and monitor enhanced habitats. On the same basis, more public sector ecologists with matching skills will be needed to evaluate developers’ proposals. Specific skills in botanical identification are required to use the Biodiversity Metric, and these are in short supply even among the existing cohort of ecologists. On the private sector side, developers, land buyers, architects and landscape architects will need to work with ecologists in new ways, to successfully integrate biodiversity net gain into developments.

In 2019, a Defra indicated that a streamlined approach to biodiversity net gain would be proposed for smaller developments, avoiding the need for ecological surveys. ³⁸ Instead, Defra's draft Small Sites Metric 2021 ³⁹ is a mini version of the main Biodiversity Metric, with more limited features. It requires a simpler habitat survey, undertaken by a ‘competent person’ and suggests that this could be a project manager or an architect. However, neither project managers nor architects currently receive any training in plant identification. A landscape architect could potentially identify simple habitats, but these are rarely employed on smaller projects and are in short supply. ⁴⁰ Therefore, both large and small developments will be affected by a skills gap.

England has a network of charitable Wildlife Trusts with decades of practical experience in habitat management and creation, which could become a valuable resource for developers if differences in outlook can be bridged. Deeper collaboration is also required on the public sector side, as local authorities (who report to the Department for Levelling Up, Housing and Communities) have been tasked with delivering policies owned by the Defra and its agency Natural England. Clearly, new collaborative working practices spanning the private, public and charitable sectors will be required to successfully deliver net gain policies.

Conclusion

The new biodiversity net gain legislation represents a historic milestone, and a vital step towards reversing the long-term depletion of the natural environment by human activity. We believe that the policies require further refinement to deliver the vision of ‘bigger, better and more joined up places for nature’. In particular, the mitigation hierarchy guidance should be revised to encourage a better balance between on-site mitigation and contribution to ecological networks. The Biodiversity Metric's spatial risk multiplier should be revised to better incentivise offsetting within the nearest local nature recovery network, including in neighbouring local authorities.

To date, biodiversity net gain policies have only been applied in a few local authorities in England, and only to major projects. To roll out these policies across all of England will require a much bigger cohort of ecologists, further specialist training, new working practices for developers and their teams, and new collaborative working practices spanning the private, public and charitable sectors. This in turn will require investment in large scale information and engagement campaigns and sufficient time for new working practices to bed down. We recommend that the Small Sites Metric should be further simplified to avoid widening the existing skills gap.