Planning Requirements For New Homes – 10% Biodiversity Net Gain

In the contemporary realm of Landscape Design and Management, a new term has emerged and is taking the industry by storm: Biodiversity Net Gain (BNG). This game-changing concept, mandated by the 2021 Environment Act, is now a compulsory element in the planning process for new developments, reshaping Landscape Planning and the design process on a national scale.

As we explore the ins and outs of the 10% Biodiversity Net Gain, we’ll uncover how this concept has the power to create a more balanced and sustainable future, painting a new picture for the landscapes of tomorrow.

What is Biodiversity Net Gain?

The Local Government Association define Biodiversity Net Gain (BNG) as an initiative aimed at enhancing the natural environment through development or land management, leading to richer biodiversity than what was originally present. Biodiversity refers to the diverse array of living species, including plants, animals, fungi, and bacteria, found on Earth. By considering both natural and man-made habitats, BNG is integral for maintaining an environment conducive to human life and sustainable economic activities.

2021 Environment Act

The 2021 Environment Act highlights BNG as a vital aspect of development, filling the gaps in environmental protection left by the UK’s departure from the EU. The Act outlines clear objectives concerning air quality, biodiversity, water and waste management, and reversing species decline.

Notably, it has set a target to reduce particulate matter concentrations (PM2.5), a pollutant highly detrimental to human health. This legislation addresses environmental protection from a perspective of social justice, acknowledging that pollution levels often disproportionately impact less advantaged areas.

Implications for Planning Requirements

The Act stipulates a new planning condition: a mandatory 10% net gain in biodiversity for all new developments. To demonstrate compliance, developers are required to submit a BNG plan to their local planning authority for approval before initiating any construction. This plan must detail an assessment of the site’s natural habitats before and after the proposed development.

The concept of BNG is increasingly recognised across local planning authorities, with many setting policies that exceed the 10% minimum requirement. Developers who integrate an effective BNG plan into their proposals from the early stages are less likely to face objections on the grounds of ecological harm or nature conservation.

Developers are advised to work with specialists to understand complex requirements like habitat quality and long-term maintenance. The Defra biodiversity metric is a standard tool used for measuring biodiversity in “units.” Developers can meet the BNG requirement either through on-site enhancements or approved off-site compensations, like contributing to a biodiversity register or buying biodiversity credits.

Mixed Beech Woodland

What Does This Mean for On-site Improvements?

In the context of Biodiversity Net Gain, on-site improvements are about enhancing and optimising the biodiversity within the development site. This approach involves fostering a healthier and more ecologically diverse environment within the premises. An effective strategy for on-site improvements considers every element of the site, from the soil composition to the flora and fauna that inhabit it.

For instance, the landscape may be designed to include more green spaces or to reintroduce native plant species that are beneficial for the local ecosystem. The site could also incorporate features such as rain gardens, bioswales, or green roofs that provide habitat while also contributing to other ecological functions. Additionally, it’s possible to provide nesting sites for birds, bats, and insects within the construction design, further boosting the site’s biodiversity.

However, on-site improvements must be planned carefully to ensure that they don’t inadvertently harm existing ecological features. Therefore, a comprehensive ecological survey is usually conducted before work begins, which provides a baseline for measuring improvements and highlights any areas that require particular attention or protection.

What Are Off-site Improvements?

Off-site improvements are measures taken outside the development site to compensate for unavoidable biodiversity losses within it. They are usually considered when it is not feasible to achieve the required biodiversity net gain solely through on-site actions. Off-site improvements are typically delivered in locations where they would contribute most to strategic biodiversity and ecosystem objectives.

Badger in Woodland
Boardwalk over water with trees

How Does LVIA Differ From Landscape And Visual Appraisal?

Landscape and Visual Appraisal is a process whereby existing landscape characteristics are recorded in order to inform decisions on future development proposals. It typically involves the mapping of land uses, vegetation types, views, and access points to enable an understanding of the existing landscape character. An LVIA goes further than this by taking into account the potential impacts that any proposed development may have on the physical characteristics and visual quality of the landscape in question. An LVIA will assess the level of impact of a proposed development. An LVA on the other hand will be less detailed and whilst it will set out the character and the landscape visual effects of a development it will not go as far as attributing a level of significance the proposed development will have on surrounding receptors (e.g. Moderate Adverse).

Different Types of Landscaping Reports Available

In addition to LVIAs and LVAs, there are several other types of landscaping reports which may be used to inform decision-making on proposed developments. These include Landscape Character Assessments (LCA) and Townscape Character Assessments (TCA).

All these reports are used to evaluate the impact of development on existing landscapes and townscapes. LVIAs/LVAs focus mainly on visual aspects. In contrast, a TCA looks at the particular characteristics of a built-up environment, such as its buildings, public spaces and the relationship between them.

These improvements could include restoring or creating habitats in areas that have been identified as needing enhancement. For instance, a developer might fund tree-planting initiatives, the creation of new wetlands, or the enhancement of existing natural sites. It might also involve improving connectivity between habitats, enabling species to move more easily across the landscape.

The aim of off-site improvements is to ensure that the overall biodiversity net gain is achieved, even when on-site measures are insufficient. However, they should not be seen as an easy alternative to on-site enhancements. The priority should always be to avoid and mitigate biodiversity loss within the development site first.

Exceptions to the Rule

The Biodiversity Net Gain (BNG) requirement under the Environment Act 2021 applies to most types of development. However, there are several important exceptions. One is that sites of high ecological value, such as Sites of Special Scientific Interest (SSSIs) or areas with protected species, follow different regulations. In these instances, the focus shifts towards avoiding harm to the biodiversity and managing the site to maintain or enhance its ecological value.

Permitted developments and householder applications, which typically involve minor changes to existing properties, are also exempt. The same applies to small-scale self-build and custom-build sites, reflecting the smaller impact such developments usually have on biodiversity.

Exceptions also include developments impacting habitats of an area below 25 square meters or 5 meters for linear habitats like hedgerows. Furthermore, urgent crown development or other development types prescribed by the Secretary of State fall outside the purview of the BNG requirement.

Nationally significant infrastructure projects, military developments, and certain urban development projects may also be exempt from the BNG requirement. In addition, irreplaceable habitats like ancient woodland, sand dunes, and salt marshes are exempted since the focus in these areas is on preservation rather than improvement.

Marine development is another area that, for now, isn’t included under the BNG requirement, although the government is working to address this and define a marine net gain approach separately.

How Can We Help? Working With Ecologists to Deliver Biodiversity Net Gain

Our company excels in delivering high-quality Landscape Design that does not compromise on ecological value. We achieve this by working closely with expert ecologists throughout the planning and design processes. From the initial plant selection to the detailed material specification, our experienced team ensures that every aspect of the project contributes to the Biodiversity Net Gain.

We provide innovative Landscape Management solutions that integrate seamlessly with the natural environment while fulfilling all the requirements set by the 2021 Environment Act. Our landscape architects are committed to creating designs that not only meet the mandatory 10% net gain but often exceed it, offering clients a unique selling point for their developments.


The 10% Biodiversity Net Gain requirement presents a golden opportunity to enhance our built environment in a sustainable and environmentally friendly manner. For developers searching for landscape architects that understand the intricacies of the new regulation, our team is ready to guide you through the process, ensuring compliance with BNG principles without compromising on aesthetics or functionality.

This new approach to Landscape Planning is not just about meeting legislative requirements – it is about embracing an exciting future in which architecture and nature exist in harmony, contributing to a healthier, more biodiverse world. This is the future of Environmental Planning, and we are here to help you be a part of it.

Wildflower Meadow in Summer