At Civity, we understand the complexities and challenges faced by developers, local planning authorities, and landowners in navigating the new mandatory BNG requirements. With the Environment Act 2021 making BNG a legal obligation for most developments in England, it’s crucial to have a clear understanding of how to conduct a Biodiversity Net Gain assessment.
This comprehensive guide will walk you through the process of conducting a Biodiversity Net Gain assessment, from initial habitat surveys to the creation of a biodiversity gain plan. We’ll cover the key components of the biodiversity net gain approach, explain how to use the biodiversity metric, and provide practical tips for achieving and delivering biodiversity net gain in your development projects.
Understanding Biodiversity Net Gain
Before diving into the assessment process, it’s essential to grasp the fundamental concepts of Biodiversity Net Gain.
What is Biodiversity Net Gain?
Biodiversity Net Gain is an approach to development that aims to leave the natural environment in a measurably better state than before. The core principle is simple: development projects must deliver an increase in biodiversity value compared to the pre-development biodiversity value of the site.
Under the Environment Act 2021, most developments in England are required to deliver a minimum 10% net gain in biodiversity. This mandatory biodiversity net gain requirement ensures that development contributes positively to nature recovery and environmental enhancement.
Key Components of BNG
- Biodiversity Metric: A standardised tool developed by Natural England to measure biodiversity value.
- Pre-development Biodiversity Value: The baseline ecological value of a site before development.
- Post-development Biodiversity Value: The predicted ecological value of a site after development, including any enhancements or created habitats.
- Net Gain: The requirement to achieve at least a 10% increase in biodiversity value.
- Biodiversity Gain Plan: A document detailing how the net gain will be achieved and maintained.
The Legal Framework
The National Planning Policy Framework (NPPF) has long encouraged net gains for biodiversity. However, the Environment Act 2021 has made it a legal requirement. This applies to most developments under the Town and Country Planning Act 1990, including Nationally Significant Infrastructure Projects (NSIPs).
Local planning authorities play a crucial role in implementing and enforcing BNG requirements. Many local authorities have also developed their own policies and strategies for biodiversity enhancement, often tied to Local Nature Recovery Strategies (LNRS).
Steps in Conducting a Biodiversity Net Gain Assessment
Now that we’ve covered the basics let’s dive into the step-by-step process of conducting a Biodiversity Net Gain assessment.
Step 1: Initial Habitat Surveys
The first step in any BNG assessment is to establish the pre-development biodiversity value of the site. This involves conducting thorough initial habitat surveys.
- Desk Study: Begin by gathering existing information about the site. This may include:
- Previous ecological surveys
- Local biodiversity records
- Aerial photographs
- Information on nearby protected sites or species
- Phase 1 Habitat Survey: Conduct a comprehensive site visit to map and classify the habitats present. This survey should:
- Identify and map all habitat types
- Assess the condition of each habitat
- Note any indicators of protected species
- Detailed Botanical Surveys: For certain habitat types, more detailed surveys may be necessary to accurately assess their quality and distinctiveness.
- Protected Species Surveys: If initial surveys indicate the potential presence of protected species, further targeted surveys may be required.
Remember, the accuracy of these initial surveys is crucial, as they form the basis for all subsequent calculations and assessments.
Step 2: Using the Biodiversity Metric
Once you have a clear picture of the existing habitats, it’s time to use the statutory biodiversity metric to calculate the site’s biodiversity value.
- Choose the Appropriate Metric: Natural England provides different versions of the metric, including small sites metric for smaller developments. Ensure you’re using the latest version of the appropriate metric.
- Input Habitat Data: Enter the data from your habitat surveys into the metric tool. This includes:
- Habitat types
- The area or length of each habitat
- Condition of each habitat
- Strategic significance (based on local conservation priorities)
- Calculate Baseline Units: The metric will calculate the number of biodiversity units present on the site pre-development. This forms your baseline biodiversity value.
- Input Post-development Scenario: Based on the development proposals, input the predicted post-development habitats. This should include:
- Habitats to be retained
- Habitats to be lost
- New habitats to be created
- Existing habitats to be enhanced
- Calculate Net Change: The metric will then calculate the net change in biodiversity units, showing whether you’re achieving the required 10% net gain.
It’s important to note that the biodiversity metric is a proxy measure and should be used alongside ecological expertise and judgment.
Step 3: Applying the Mitigation Hierarchy
The biodiversity gain hierarchy, based on the mitigation hierarchy, should guide your approach to achieving net gain:
- Avoid: The first step is to avoid impacts on biodiversity wherever possible. This might involve:
- Redesigning the development layout to preserve high-value habitats
- Timing works to avoid sensitive periods for wildlife
- Mitigate: Where impacts can’t be avoided, seek to minimise them through mitigation measures. This could include:
- Creating buffer zones around sensitive habitats
- Implementing measures to reduce disturbance to wildlife
- Compensate: As a last resort, compensate for unavoidable losses. This is where habitat creation and enhancement come into play.
By following this hierarchy, you can demonstrate to the relevant local planning authority that you’ve taken a responsible approach to biodiversity conservation.
Step 4: Designing for Net Gain
With your baseline established and the mitigation hierarchy applied, it’s time to design your biodiversity net gain strategy. This is where creativity and ecological expertise come together.
- On-site Measures: Prioritize on-site habitat creation and enhancement. This could include:
- Creating new habitats such as wildflower meadows or wetlands
- Enhancing existing habitats through improved management
- Incorporating green infrastructure like green roofs or wildlife-friendly landscaping
- Off-site Measures: If on-site measures aren’t sufficient to achieve the required gain, consider off-site options:
- Securing land for habitat creation or enhancement
- Purchasing biodiversity units from habitat banks
- As a last resort, purchasing statutory biodiversity credits
- Long-term Management: Remember that biodiversity gains need to be maintained for at least 30 years. Design a realistic, long-term management plan.
- Monitoring and Reporting: Include provisions for ongoing monitoring to ensure the biodiversity gains are being achieved over time.
Step 5: Preparing the Biodiversity Gain Plan
The biodiversity gain plan is a crucial document that demonstrates how your development will achieve net gain. It should include:
- Site Information: Details of the development site and proposed works.
- Pre-development Biodiversity Value: Results of your initial surveys and metric calculations.
- Steps Taken to Minimize Impacts: How you’ve applied the mitigation hierarchy.
- Post-development Biodiversity Value: Predicted biodiversity value after development, including all enhancements.
- Net Gain Calculations: Demonstrating at least a 10% net gain.
- Off-site Gains: If applicable, details of any off-site measures, including locations and agreements.
- Management and Monitoring Plan: How biodiversity gains will be maintained over the long term.
- Supporting Evidence: This might include survey reports, metric calculations, and site plans.
The biodiversity gain plan needs to be approved by the local planning authority before development can commence.
Challenges and Considerations
While conducting a Biodiversity Net Gain assessment, there are several challenges and considerations to keep in mind:
Dealing with Irreplaceable Habitats
Some habitats, such as ancient woodland, are considered irreplaceable. These habitats are exempt from the BNG requirement, but their loss must still be addressed through the planning process.
Timing Considerations
Ecological surveys are often seasonally constrained. Plan your assessment timeline carefully to ensure you can gather all necessary data.
Balancing BNG with Other Requirements
Achieving biodiversity net gain needs to be balanced with other planning requirements and development needs. Early integration of BNG into the design process can help manage potential conflicts.
Technical Complexities
The biodiversity metric and associated calculations can be complex. It’s often beneficial to work with experienced ecologists who can navigate these technicalities.
Long-term Management
Securing and implementing long-term management (minimum 30 years) can be challenging. Consider using planning obligations or conservation covenants to secure these commitments.
Best Practices for Successful BNG Assessments
Based on our experience at Civity, here are some best practices for conducting successful Biodiversity Net Gain assessments:
- Early Integration: Incorporate BNG considerations into your project from the earliest stages. This can lead to more cost-effective and ecologically beneficial solutions.
- Engage Experts: Work with qualified ecologists who understand both the technical aspects of BNG and the local ecological context.
- Communicate with Stakeholders: Engage early with local planning authorities. conservation bodies, and local communities. Their input can be valuable in shaping your BNG strategy.
- Be Creative: Look for innovative ways to enhance biodiversity that align with your development goals. This could include multi-functional green spaces or novel habitat-creation techniques.
- Plan for the Long Term: Consider the long-term viability and management of created or enhanced habitats. Aim for solutions that are sustainable over the required 30-year period and beyond.
- Keep Detailed Records: Maintain comprehensive records of your surveys, calculations, and decision-making processes. This will be invaluable when preparing your biodiversity gain plan.
- Stay Informed: BNG policy and best practices are still evolving. Stay up-to-date with the latest guidance and engage in professional development opportunities.
The Role of Technology in BNG Assessments
Advancements in technology are playing an increasingly important role in conducting Biodiversity Net Gain assessments:
- GIS Mapping: Geographical Information Systems (GIS) can greatly enhance the accuracy and efficiency of habitat mapping and analysis.
- Remote Sensing: Techniques like LiDAR and satellite imagery can provide valuable data, especially for large or inaccessible sites.
- Mobile Apps: Field survey apps can streamline data collection and improve consistency.
- Biodiversity Databases: Online biodiversity record centres can provide valuable contextual data for your assessments.
- Modelling Software: Advanced ecological modelling tools can help predict the outcomes of different habitat creation and enhancement scenarios.
At Civity, we stay at the forefront of these technological advancements to ensure we’re providing the most accurate and efficient BNG assessments possible.
The Future of Biodiversity Net Gain
As we look to the future, several trends are likely to shape the practice of Biodiversity Net Gain assessments:
- Integration with Ecosystem Services: We anticipate growing integration between BNG and broader natural capital and ecosystem services approaches.
- Advances in Metrics: The biodiversity metric is likely to evolve, potentially incorporating more sophisticated measures of ecological function and connectivity.
- Standardisation of Offsite Gains: The market for biodiversity units is likely to mature, with more standardised approaches to offsite gains and potentially a national biodiversity credit scheme.
- Climate Change Considerations: BNG assessments may increasingly need to consider the potential impacts of climate change on created and enhanced habitats.
- Broader Application: The principles of BNG may be applied to a wider range of projects, potentially including marine environments and smaller developments.
At Civity, we’re committed to staying at the forefront of these developments, ensuring our clients always receive the most up-to-date and effective BNG solutions.
Embracing the BNG Challenge
Conducting a Biodiversity Net Gain assessment may seem daunting at first, but with the right approach and expertise, it can be a rewarding process that delivers real benefits for both development and nature conservation.
By following the steps outlined in this guide – from initial habitat surveys through to the preparation of a comprehensive biodiversity gain plan – you can navigate the BNG process successfully. Remember that the goal is not just to meet a regulatory requirement, but to make a genuine positive contribution to biodiversity and the natural environment.
At Civity, we’re passionate about helping our clients achieve meaningful biodiversity gains. Whether you’re a developer grappling with BNG for the first time, a local planning authority developing BNG policies, or a landowner exploring opportunities to provide biodiversity units, we’re here to help.
Biodiversity Net Gain represents a significant shift in how we approach development, placing nature at the heart of the planning process. By embracing this challenge, we can create developments that not only meet human needs but also enhance the natural world around us.If you’re ready to start your Biodiversity Net Gain journey, or if you have any questions about conducting a BNG assessment, don’t hesitate to reach out to us at Civity. Together, we can create a future where development and nature thrive side by side.
