Biodiversity specialist at CSX and qualifying member of the Chartered Institute for Ecology and Environmental Management (CIEEM), Lucy Stephenson, examines the extent to which the expertise of an ecologist can be scaled with the advanced earth observation-based monitoring and machine learning technologies available today.

The initial step in any land assessment is understanding the value of the habitats residing, a task traditionally delivered by ecologists undertaking a walkover survey. However, as BNG and Nature Related Financial Disclosure significantly expand the land area to be assessed, can the judgement of individuals walking the ground deliver scale when robust, reliable data provides an alternative.

Since the Biodiversity Net Gain (BNG) legislation came into effect in February 2024, it has presented challenges for developers and local planning authorities as they navigate the complexities of assessing the habitat units on each piece of land. Nearly a year on, the Section 106 agreements ensuring biodiversity net gain is delivered on every development are only slowly beginning to be finalised.

This underlines the importance of having indisputable data to ensure that progress is maintained. It is here that the ecologists can deliver scale with earth observation and machine-based monitoring, to best identify the units required quickly and accurately.

The dawn of precision with drone technology

Since its establishment in 1991, CIEEM has set the standard for qualified knowledge and practice in the field. However, despite incremental improvements, the core processes have remained largely unchanged. While discussions around classification and monitoring have evolved, the conventional approach still involves selecting sections of an area, assessing the vegetation habitat or wildlife species present, and expanding the findings to the whole.

One of the most significant developments was using Google Earth for assessment processes. For the first time, ecologists could combine on-site assessments with a bird’s-eye view of the entire project area. However, satellite imagery often provides a low-resolution support for conclusions that had already been drawn.

Now, with the introduction of drone technology, this has dramatically enhanced this process. We can now capture a detailed and highly accurate digital twin representation of an entire area within a few hours, producing a comprehensive overview of the habitat and its condition. Accuracy in mapping habitats is crucial, particularly for BNG assessments, where metrics are heavily based on the habitat type, size and condition. Drone surveying allows precise mapping, which is arguably more accurate in comparison to traditional methods that rely on on-the-ground estimates and satellite images. This level of precision ensures that calculations for BNG metrics are as exact as possible, a crucial factor for developers when considering the viability of a potential site for development.

As a comparison, free to access satellite data has a best resolution of 10 metres. Satellite imagery at 1-2m resolution is now available for many parts of the world, at quite some cost per area covered. The newer satellite constellations can provide data at around 50cm resolution, normally with high costs per data set, and it is claimed that satellite data providers from countries like China and India will soon cover the western world to a resolution of around 10cm.

CSX gathers drone data for BNG across the whole site at a resolution of 0.75cm with quadrats at 0.05cm Ground Sampling Distance. Not only does this allow for high accuracy, significantly reducing the subjectivity often involved in determining habitat classifications, but drone data can additionally be automated to collect repeatable data, crucial for on-going BNG monitoring.

The ability to conduct consistent surveys over time enables ecologists and developers to track habitat progression with confidence, ensuring that any changes in the habitat are accurately captured and reported. Conversely, unnecessary return visits to capture missing data are avoided, which enhances the efficiency of the process.

The technology’s application is even more advanced and importantly, repeatable, this is essential when gathering data. The high-resolution data gathered by drone can be analysed to produce models that predict areas of water accumulation and suggest areas where ponds could be placed, aiding developers in flood risk identification. Additional applications of the drone data models include the representation of vegetation structures which may uncover the condition and distinctiveness of a habitat. These insights go beyond the capabilities of traditional site walkovers, providing a more dynamic and detailed understanding of land conditions.

The role of human expertise

While the advantages of technology are clear for scaling the surveying of land, the importance of human expertise should not be underestimated. Habitats are complex, and there are situations where manual assessment needs to emerge as an ally, lending insight and depth to the overall process.

However, human judgement, while invaluable, is subject to limitations, including subjectivity and external influences. For example, two ecologists may assess the same piece of land and arrive at different conclusions due to varying interpretations. This is where technology proves its value, offering an objective and data-driven perspective that can confirm or challenge initial human assessments.

Moreover, BNG and Nature Related Financial Disclosure require repeat monitoring over time. Making repeatable non-subjective assessments critical to the integrity and credibility of the reporting for these requirements.

Drone technology, when used in tandem with traditional methods, provides a layer of confidence, offering concrete evidence that supports or refines an ecologist’s evaluation. Additionally, drones provide scalability and efficiency, enabling quicker assessments across larger areas and reducing the resources needed for site visits. For larger or more complex sites, drones deliver a comprehensive overview that might take ecologists days to cover manually.

This is particularly relevant when assessing unique or mosaic habitats, such as Open Mosaic Habitats (OMH) on previously developed land. These areas often present challenges in classification, and debates about their status can delay development. Drone technology, combined with ecological assessments, can precisely assess vegetation structure and habitat types, aiding developers in navigating these complex environments.

A collaborative future

The successful future scaling of ecological assessments, particularly in the context of biodiversity net gain, will increasingly hinge on the integration of advanced data-driven technologies. While ecologists bring an irreplaceable depth of understanding to complex habitats, it is the precision, scale, and repeatability of technology drones, earth observation, and machine learning that will shape the future of biodiversity assessments, ensuring compliance with biodiversity legislation every step of the way.

Data should become the backbone of ecological evaluations, with human expertise stepping in to provide interpretation, guidance, and validation where necessary. This collaborative approach will ensure that assessments remain both accurate and scalable. Ecologists will work alongside it, enhancing the depth of understanding while leveraging the reach and consistency that technology affords.

Furthermore, as the market for BNG continues to evolve, data and technology will play an increasingly central role in shaping future biodiversity assessments. Tools such as drones not only improve the accuracy of current assessments but also lay the groundwork for integrating biodiversity strategies with broader environmental impact analyses, offering insights into how climate and biodiversity shift over time.

Dynamic, data-rich monitoring will be key to future success. With systems that deliver highly accurate and repeatable data, technology will lead the charge in ensuring that biodiversity net gain is measured reliably. This will enable developers to navigate the complexities of environmental projects more effectively, ensuring both biodiversity and developmental goals are met.

To learn more about CSX’s technological advancements in monitoring wildlife and habitats, visit csxcarbon.com.