HRE’s ‘Minding the Gap’ programme could change the way brownfield sites are assessed for biodiversity and reconnect fragmented habitats.
The Historical Railways Estate (HRE) is responsible for a collection of over 3,100 disused railway assets that were once part of the national rail network. Its assets include former railway bridges, tunnels, viaducts, and culverts that are no longer in active railway use but have not been removed or redeveloped. The HRE is managed by National Highway’s on behalf of the Department for Transport (DfT) and plays a unique role in both heritage conservation and public safety.
Along with its partners, contractor Balfour Beatty and Edinburgh Napier University, in July last year, the HRE began an innovative study assessing the environmental importance of brownfield sites – previously developed land, which is or was once occupied by a permanent structure. The ‘Minding the Gap’ programme could change the way brownfield sites are assessed in the future in terms of their unique biodiversity value and reconnecting fragmented habitats vital to plant and wildlife populations.
The work includes using innovative sound surveys and site DNA testing alongside more traditional techniques such as visual surveys and camera traps to get a detailed picture of biodiversity at five trial HRE sites. RailStaff spoke with Dr Jennifer Dodd of Edinburgh Napier University to find out more.
Hi Jenny, could you give us a snapshot of your professional background and tell us how you came to be involved in this study?
I have been based at Edinburgh Napier University since October 2018. Prior to that I worked at various other universities and set up my own environmental consultancy in 2015. I have been working in the field of biodiversity assessment and monitoring for almost 20 years. My work initially focussed on freshwaters – rivers and lakes – but my interests have expanded and now covers all ecosystems. I am particularly interested in emerging ecosystems and the role they can play in supporting biodiversity across our landscapes. An emerging ecosystem is any novel or newly formed ecosystems that humans have created either through disturbance (e.g., brownfield) or by trying to rehabilitate the environment (e.g., habitat restoration).
Why are brownfield sites so important in supporting wildlife and plants?
Brownfield systems have a bad reputation. They are frequently overlooked and dismissed as wasteland that has lost purpose. However, the very fact that they are different means that they can often support a diverse range of animals and plants that we don’t typically find together in other habitats. The unique biodiversity is due to two main reasons. Firstly, brownfields have an unusual mix of habitat types – this includes bare grounds and walls that provide basking spots for insects and are full of cracks and crevices for animals and plants to live. These man-made habitats are overlayed with dense vegetation full of garden escapees, bramble, and pioneering trees such as ash and rowan. All of which are provide plenty of flowers for pollinators such as bees, hoverflies and moths and berries for birds and mammals to eat.
Secondly, brownfields are disturbed habitats – they have been created through human action. In the case of the National Highways HRE sites, these sites are constantly disturbed for repair and maintenance of structures. These disturbances, when not too extensive, can mimic the natural disturbances such as fires or storms. This can promote biodiversity, through creating new habitats effectively resetting parts of the vegetation and allowing space for new plants to grow alongside the old.
Depending on their location, brownfield sites can also support habitat connectivity by providing links between existing habitat networks allowing for nature to traverse urban landscapes while avoiding barriers such as busy roads.
What is the purpose of the study and what are the expected outcomes?
Biodiversity refers to all organisms living, within a given area, whether all year round or migrating visitors such as our cuckoos, song thrushes, and Bohemian waxwings. The purpose of Minding the Gap for Biodiversity is to assess the biodiversity that is supported by the non-live part of the National Highways railway network. We are therefore undertaking a truly holistic assessment at our study sites and recording biodiversity ranging from the bacteria and fungi in the soil, to the invertebrates and the plants, and the birds and the mammals.
The project team at Edinburgh Napier University is combining traditional survey methods such as visual surveys, with emerging technologies like passive acoustic monitoring and environmental DNA to capture as much information as possible regarding biodiversity.
We can then use this information to provide National Highways and Balfour Beatty with advice about how to support the existing biodiversity on their sites and how to improve the sites to support biodiversity for the future.
The sites that National Highways own are specifically interesting and important as they contain infrastructure – e.g. tunnels, supporting walls, bridges – that must be maintained. Part of this maintenance requires the sites to be periodically disturbed through the removal of plants and trees and the movement of soil. This ongoing disturbance maintains and, in fact, can even increase the levels of biodiversity, making sites within this estate of particular importance in supporting biodiversity at a national landscape level.
What brownfield sites are included in the study and why they were chosen?
In collaboration with Balfour Beatty and the Historical Railways Estate, we identified a suite of sites to try to capture the variability of brownfield habitats within the Heritage Railway Estate. Our sites include a mix of overbridges, tunnel, and retained land in Greenock; a similar mix of features at a site in Glasgow; an overbridge in Williamwood; an overbridge spanning a former railway in Glencorse; and a viaduct in Bonnyrigg.
We are also monitoring sites of nearby ancient woodlands, which will allow us to compare the results from our brownfields with that of a perceived high-quality habitat for biodiversity.
What techniques and equipment are you using at these sites?
To capture this level of information about the biodiversity at our study sites, we visit sites weekly as we need to see how the animals and plants change across the year. Capturing this holistic assessment of biodiversity is therefore time consuming and costly. We are using emerging technologies to compare with traditional approaches to explore the extent to which we can automate the process of biodiversity assessment and monitoring.
One of the technologies we are using is passive acoustic monitoring, where we deploy microphones in the air and in the soil to listen to the sounds in the environment – this is often referred to as the soundscape and there is emerging evidence that soundscapes can provide information about the biodiversity within a given area. We will compare the patterns of sound that we record with the other measures of biodiversity that we are collecting.
These other measures of biodiversity include information gathered from camera traps and traditional approaches where surveyors undertake visual assessment – for example, bird counts or vegetation surveys. We are also collecting environmental DNA. The type and strength of relationship between the acoustic data and the other sources of biodiversity information will tell us about how this technology can be used in the future.
Finally, what are the wider aims of the study – how will its results help to tackle the current crisis in biodiversity?
Finding the best balance between how we use the landscape to meet our demands in terms of infrastructure (e.g. housing, building, and transport) as well as food production, while reversing the negative impact human activity has on biodiversity, is an enormous challenge. One of the key challenges to address the biodiversity crisis is identifying areas across our landscape which are of particular importance in terms of supporting biodiversity. By identifying these sites, we can focus our efforts on key areas to better support and improve biodiversity and use this information to better manage our landscape to reverse biodiversity loss.
The exciting innovation this project brings is that we are generating considerable amounts of high-quality data to look for patterns of association between traditional and emerging approaches to biodiversity assessments. We will explore the options for automation of data processing (for example, by using machine learning), with the potential to deploy a system of automated monitoring which would be scalable. Ultimately allowing us to assess and monitor biodiversity at much larger scales over longer periods of time.
We have some distance to get to this point, but the high-quality information that this project is collecting provides an excellent foundation of data to support the development of these cutting-edge biodiversity assessment tools.
Image credit: iStockphoto.com
