The top five mistakes developers could make with new BNG rules

7 May 2024 | 9 min read

The top five mistakes developers could make with new BNG rules

As the environmental landscape undergoes significant changes with the implementation of Biodiversity Net Gain (BNG) rules, developers find themselves navigating uncharted territory. The introduction of new metrics and regulations by Defra demands a meticulous approach to habitat classification and conservation. Overlooking crucial aspects could lead to costly mistakes and hinder the successful implementation of BNG strategies.

At AiDash we recognize the enormity of this task and understand that navigating these requirements can be challenging. In this blog, we will shed light on the top five mistakes developers are at risk of making with the new BNG rules now in force and demonstrate how our tools can help mitigate these risks.

1. Underestimating the level of change

Meeting BNG requirements is no small feat. While familiarity with the existing UKHab or EUNIS habitat classification may seem like a solid foundation, the introduction of new metrics by Defra requires an entirely different approach to habitat classification. BNG has a standardized classification system and previous systems – i.e. Phase 1, are incompatible with BNG due to differences in definition and naming. Put simply, the ecological survey needs to conform to the BNG classes and condition assessments. Underestimating this level of change and using other systems can lead to complications such as misinterpretation of ecological data and inaccurate reporting.

Additionally, developers are now responsible for on-site BNG and will need to provide plans for managing and maintenance obligations to the Local Planning Authority (LPA) over a period of 30 years. In this plan, developers must consider legal agreements, reporting, and future proposals.

AiDash have developed a BNG AI portal in line with the 2021 Environment Act. The platform offers support throughout the process, alleviating some of the organizational burdens and helping streamline the process. In the case of the 30-year management plan, the portal will provide timely prompts for report submissions and the resources needed to stay on track.

2. Assuming market credits will be easily available

When adopting BNG rules, developers should avoid the assumption that off-site BNG credits will be easily accessible. The credit market is still evolving, and it is impossible to say what the demand and supply will be at this stage. While opting for off-site credits may seem convenient as it requires less management, it involves complex third-party agreements. Moreover, there are limits to where credits can be purchased; the development must be in near proximity to the development, ideally within the same National Character Area or an adjacent NCA. This can pose a challenge as suitable nearby projects must gain approval from the LPA. And, if credits are available, they may not be of the type required to offset the habitats impacted on-site, not to mention the cost of net gain will increase significantly if the development relies solely on third party credits. To limit reliance and risk associated with off-site credits, developers should strive to maximize on-site BNG by considering their site selection carefully.

Satellite imagery and AI technology offer powerful tools to assist developers in their site selection by assessing the ecological value of the area and identifying opportunities to optimize on-site BNG. This process ensures developments have every opportunity to align with Local Nature Recovery Strategies (LNRS), ensuring that prospect development is complimentary of local government and conservation targets. Developers should refer to the LNRS when preparing for BNG requirements, and AiDash’s portal provides additional data layers to support assessments.

3. Failing to map the area properly

To achieve BNG to a high standard, sites must be properly accounted for. This process involves habitat mapping, which forms the baseline data, and any inaccuracies at this stage risk compromising net gain calculations from the very beginning. Complying with the new rules is a huge undertaking, and with limited resources, developers may overlook the importance of ensuring the accuracy of their surveys.

Free tools are available for building habitat maps but it’s essential to note that these tools, while they can be effective in mapping, lack the necessary detail and alignment with DEFRA’s definitions for BNG. Although free mapping tools can aid in streamlining the process, they are unlikely to remove the effort it takes to produce a high-quality map without the involvement of a technical expert. Utilizing such tools may result in overlooked details, reducing the quality of surveys at an early stage and requiring further refinement after a field assessment. Even minor discrepancies between the area of each habitat can dramatically change the value of BNG on a site.

Satellite imagery has a resolution 460 times higher than free maps, significantly enhancing accuracy. AiDash’s habitat mapping uses software designed to accurately identify the boundaries of habitats, ensuring there are no gaps or unaccounted land, and preventing the double counting of habitats. The system is fine tuned to confirm the ecological maps are consistent and conform to cartographic standards.

The BNG classification is used by the system to provide a highly accurate preliminary map (with accuracy in excess of 90% without on-field review and often at unparalleled accuracy for delineating habitat boundaries) that can be used to assess prospect locations early on. This map, utilized for assessing prospect locations, can then be exported to a professional ecologist (described as a competent person for undertaking the ecological field assessment).

This collaborative step with the ecologist ensures a comprehensive and accurate evaluation. In cases where refinement is needed, it undergoes minor adjustments by field ecologists, updates the habitat condition through field assessment and produces a 100% accurate final verification. This integrated approach offers unprecedented traceability and prevents errors that could otherwise derail the net gain strategy.

4. Small doesn’t necessarily mean small

Legislation regarding BNG will be gradually implemented for thousands of small sites in England, granting builders of smaller sites until April 2024 to prepare. A small site is defined as those where residential development consists of no more than nine dwellings, or in cases where this information is unknown, if the site area is less than 0.5 hectares. Additionally, it may use the small size metric (SSM) biodiversity calculation tool if the commercial development has floor space under 1,000 square meters or a total site less than 1 hectare, and if it does not involve winning and working of minerals, use of land for mineral-working deposits, or waste development.

However, just because a site is small doesn’t mean it qualifies for a small site metric. If the site contains priority habitats (those with a high biodiversity value such as bogs or rivers), or includes habitats not covered by the SSM, then the statutory calculation tool must be applied.

Developers must be certain that their surveys are completely accurate so that there is no confusion over classification. For example, a site with a small area may contain highly distinctive grassland, such as lowland meadow priority habitat, but this might be mistaken for a lower value grassland. Thus, the site does not qualify for SSM and will fail to comply with BNG requirements leading to delays or the rejection of planning applications.

By utilizing AiDash’s process to ensure accurate habitat mapping, developers mitigate this risk of misclassification and support the selection of the correct metric for the development.

5. Underestimating the expertise needed

BNG is a complex piece of legislation that demands specialist expertise and resourcing to ensure accurate application to projects. Often, more than one ecologist is required per project; a project might necessitate a specialist for land habitats and river assessments respectively, for example. Without the appropriate capabilities errors can arise, potentially leading to a failure to comply with the new legislation.

However, the shortage of ecologists in the UK complicates matters. Despite increased government funding, a significant skills gap persists.

This is why we have built the BNG AI portal, to enable accurate habitat mapping at scale, help eliminate administrative burdens so that ecologists can focus their expertise on high-value tasks and decision-making (making their efforts more impactful), and ultimately to accelerate project timelines and guarantee BNG is made possible at the speed and scale developers need.

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