Connecting habitats & how mineral & aggregates extraction sites can be a biodiversity lifeline

Unsustainable practices have led to the gradual loss and splintering of vital ecological networks in the United Kingdom. Habitat loss and fragmentation are some of the major drivers for global biodiversity decline. Simply put, a lack of diverse and connected habitats of varying sizes minimizes the chance for species to migrate, forage, and seek refuge. These habitat islands may gradually decrease in size and connectedness over time such that the threats of invasive species, pollution, and climate change are exacerbated.

Here in Northern Ireland, we are one of the worst hit. Generations of increasing and intensified use of our land has removed crucial habitat connectedness and quality, contributing to being ranked as the 12th worst out of 240 countries for biodiversity perseverance based on the Biodiversity Intactness Index (RSPB 2021). Improvements are being made with Nature Friendly Farming and policy reforms (Northern Ireland Environment Link 2021), however, there is much to consider. Surprisingly to those outside the industry, mineral and aggregates extraction sites can be a biodiversity lifeline. In a UK context, 600 sites of special scientific interest (SSSIs) are former mineral or aggregates extraction sites, with many undergoing rewilding without intervention, though many more have effective and forwardthinking restoration plans in place (Whitehouse 2008). These sites become stepping-stones between core habitat islands and are priority habitats defined as Open Mosaic Habitats on Previously Developed Land (OMH) in Northern Ireland. These habitats may also enlarge existing habitat patches, improving prosperity for biodiversity from previously mentioned threats. What makes these sites a priority begins with where sites start excavating, which is usually on biodiversity poor rural land, leading to improved richness of habitat. If excavating occurs on already

Ruby-Tailed Wasp (Chrysis sp.) on exposed cliff. © Joshua Clarke

biodiversity rich habitats, that would be poor foresight and planning. It is always better to conserve existing priority habitat (e.g., woodlands, calcareous grassland, limestone pavements and blanket bogs) than remove. It just isn’t sustainable for biodiversity. However, in land that is not already biodiverse, the process of extraction is beneficial. This opens patches of bare ground, creates varied topography such as stratified cliffs where solitary bees and wasps may nest, and may encourage wetland habitat formation of high biodiversity potential, providing for species including Scarce Blue-Tailed Damselfly (Ischnura pumilio) and the NI priority species Dull Bronze Diving Beetle (Ilybius subaeneus). The exposed bare ground is important for many reasons; firstly, it allows for warmer microclimates to develop (benefiting our often heat-loving insects), and secondly the low nutrient mineral soils delay succession to grassland. This allows nectar and pollen rich plants such as Ragwort (Jacobaea vulgaris), Common Knapweed (Centaurea nigra), Bird’sFoot Trefoil (Lotus corniculatus), Wild Thyme (Thymus drucei) and, Rosebay Willowherb (Chamerion angustifolium) to colonise and provide for numerous insects. Ragwort and knapweeds are the preferred plants of a Northern Ireland priority species, the Grey Banded Mining Bee (Andrena denticulata) which in decades gone by had been found near Scrabo. Both ragwort and knapweeds are important for a range of pollinators, from hoverflies to butterflies, which have been declining globally (Potts 2010), and are rest spots for predators and parasites including beegrabber flies (Family: Conopidae) and ichneumon/braconid wasps. Many larval stages of insects will have associations with particular plants found on OMH. For example, caterpillars of the day-flying Cinnabar Moth (Tyria jacobaea) favour Ragwort and, caterpillars of the incredibly coloured Elephant HawkMoth (Deilephila elpenor) favour willowherbs. Their presence at OMH sites this will also be dependent on overall landscape-scale conservation of the surrounding areas to increase chance of migration and colonisation. The importance of habitat connectivity and the crucial habitat OMH provide cannot be understated. Mineral sites provide opportunities for habitat creation or restoration which will increase connectivity. They can also contribute towards projects like Buglifes’ very own B-lines project which will help give pollinators a fighting chance. B-lines is expanding into Northern Ireland, aided by recent insight from success in Great Britain and contributing to

White-Footed Green Furrow Bee (Lasioglossum leucopus) feasting on Wild Thyme (Thymus drucei) on exposed cliff. © Joshua Clarke

Open Mosaic Habitat on Previously Developed Land (OMH); supporting a wide range of terrestrial and aquatic habitats. © Anna Hart

Female Grey-Banded Mining Bee (Andrena denticulata) on Ragwort. © Steven Falk

Early successional wetland habitat, important dragonfly and damselfly habitat. © Anna Hart

the All-Ireland Pollinator Plan 20212025. B-Lines seek to combat the decline in native pollinators by creating a network of (re)connected habitats. This will be achieved by encouraging wildflower meadows with no mowing policies in place and connecting with communities and industry for more bespoke plans of attack. As there are around 160 quarries, mines and sandpits in Northern Ireland, the mineral industry will be pivotal in giving our native pollinators a fighting chance by providing key habitat features. However, recording and observation of the biodiversity we currently have at these sites at all stages of development will be beneficial to quantify biodiversity triumphs. Buglife is a member of the MPANI biodiversity group and we are actively looking to build partnerships within the sector. For information please contact the Conservation Officer for Northern Ireland Joshua Clarke on 07464828623 or joshua.clarke@buglife.org.uk

For more information on managing aggregates sites for invertebrates and for our B-lines project, please visit the links. • All-Ireland Pollinator Plan 2021-2025. National Biodiversity Data Centre Series No. 25, Waterford. March 2021. • Northern Ireland Environment Link (2021) NIEL Evidence: Nature Friendly Farming for The Committee for Agriculture, Environment and Rural Affairs (AERA), 16th April 2021: http://www.niassembly.gov.uk/globalassets/committeeblocks/agricultureenvironment-and-rural-affairs/2017---2022/new-folder/farm-welfare-bill/niel-evidence---naturefriendly-farming.pdf • Potts, S. G., Biesmeijer, J. C., Kremen, C., Neumann, P., Schweiger, O. and Kunin, W. E. (2010). Global pollinator declines: trends, impacts and drivers. Trends in Ecology & Evolution 25, 345–353. • RSPB (2021) Biodiversity Loss, The UK’s global rank for levels of biodiversity loss: https://www.rspb.org.uk/ globalassets/downloads/about-us/48398rspb-biodivesity-intactness-index-summary-reportv4.pdf • Whitehouse, A. T. (2008) Managing Aggregates Sites for Invertebrates: a best practice guide. Buglife – The Invertebrate Conservation Trust, Peterborough.