title: Can anthropogenic biodiversity and geodiversity associated with legacy industrial waste help offset decreasing global biodiversity?
Creators: name: van Mesdag, Savanna Nuala Katharine
Publisher: name: University of Glasgow
Year: 2024

description: Anthropogenic substrates, including materials such as steel slag, paper mill sludge, oil shale spoil and colliery spoil, were frequently dumped and are still dumped today in many countries where such waste is produced. In some countries, dumping of such materials is restricted due to increased health and safety regulations and due to improved waste recycling streams. Such substrates have become byproducts and are used in various products and/or applications. Legacy dumps, those that have been around for many years, can theoretically be excavated for such useful byproducts, but this can be costly and time-consuming. Additionally, many legacy anthropogenic substrate sites have biodiverse and/or rare wildlife communities, as the characteristics of the substrate can support favourable or acceptable conditions for many species. Plant species that might be easily outcompeted on high-nutrient soils may benefit from reduced competition on lower-nutrient anthropogenic substrate, for example. Invertebrates on such sites can benefit from habitat mosaics, bare patches and varied topography, for example. Anthropogenic substrate sites can be grouped as a type of brownfield site, those that are associated with former industry and anthropogenic activities. Some biodiverse brownfield sites are recognised in legislation in multiple countries, for example, Open Mosaic Habitat on Previously Developed Land, or Calaminarian Grasslands. However, assessment and protection of wildlife on these sites is often lacking and they are often preferentially chosen for development by councils, governments, developers and so on. The very features of these sites which can be so advantageous to certain species are therefore vulnerable to being removed, covered or otherwise modified by people in the name of restoration, remediation or development, for example. In order to better understand the features of these sites that can be utilised by wildlife, it is important to recognise how the substrate heterogeneity and geodiversity of many anthropogenic substrates might influence or be associated with specific species, especially plants. This study addresses questions concerning the biodiversity and substrate associations of multiple plant species and communities of anthropogenic substrate sites. Substrate geochemistry and mineralogy was determined across a suite of case study sites with different types of anthropogenic substrate, in combination with plant surveys of the sites. Analyses were carried out to look for statistically significant associations between different substrate variables and the plant species and/or communities recorded on the sites. Upon examination of the biodiversity levels and substrate associations of open plant communities and species on six case study sites, high biodiversity levels and/or rare and uncommon species were recorded in multiple plant communities across all six sites. It was found that the geochemistry on capped and uncapped areas of a partially remediated slag bank, while statistically significantly different, supported biodiversity levels which were not statistically significantly different, demonstrating that both remediated and unremediated parts of the slag bank contributed to the site’s biodiversity. The sampling and analyses of overall geochemistry and plant communities and species present on two sites predominantly covered in blast furnace slag demonstrated multiple associations between decreased or elevated concentrations of certain elements and the presence of certain plant communities and species. Overall, many anthropogenic substrate sites can support high levels of biodiversity, but these can vary between substrate types. It was seen that in plant communities with lower biodiversity levels, there could be at least one rare or uncommon species present, so this study demonstrated that low biodiversity does not necessarily indicate the entire ecological value of the community. Additionally, biodiversity can be influenced by multiple factors, some of which were outside of the scope of this study due to time and sampling constraints. This study emphasises the need to assess anthropogenic substrate sites on a case-by-case basis, rather than treating them all with the same or similar management styles.