Butterfly habitat translocation and creation
Baker Consultants has recently completed the latest phase of a project to translocate species rich grassland and the dingy skipper butterfly, Erynnis tages, from a former colliery in Nottinghamshire. The population of the dingy skipper has declined seriously in recent years and is a priority species under the UK Biodiversity Action Plan. It is thought that this project is the first time that the larvae of this species have been successfully translocated to receptor sites.
- Listed as a Section 41 species of principal importance under the NERC Act in England
- Listed as a Section 42 species of principal importance under the NERC Act in Wales
- Classified as a Northern Ireland Priority Species by the NIEA
- Protected under the Nature Conservation Act in Scotland
- UK BAP status: Priority Species
- Butterfly Conservation priority: High
The colliery site in Kirkby-in-Ashfield, part of which has been earmarked for industrial development, lies within an area designated as a Local Wildlife Site for its botanical interest. In particular, the common spotted orchid, Dactylorhiza fuschii, and bee orchid, Ophrys apifera, both occur on site.
The latest phase of the project has involved the relocation of the dingy skipper, orchids and species-rich grassland from within the former colliery to adjacent receptor sites. This is being carried out by Baker Consultants with support from Mike Slater of Butterfly Conservation.
Three receptor sites were identified and prepared for species-rich grassland containing orchids and grassland turf containing dingy skipper larvae on the host plant, bird’s-foot trefoil. The location of the receptor sites in relation to the site is shown below.
- To maintain favourable conservation status for dingy skipper in the local area by minimising the potential impacts arising from the proposed development of Summit Colliery.
- To conserve plant species of ecological interest and local botanical diversity by minimising the potential impacts arising from the development of Summit Colliery.
“Orchids and butterflies prefer open vegetation and low nutrient habitats, which are unfavourable for many plants and insects to flourish so a poorer ground than is usually requested on remediation works is required. Typical ground conditions are found in neglected industrial areas and we are trying to replicate this at Summit”, said Mark Woods, Senior Ecologist at Baker Consultants.
Topsoil was removed from the receptor sites within the development area. They were then capped with a mix of aggregate formed from crushed rubble and black mineral fines (coal waste) that was processed on site. This was used both as a substrate and to infill gaps between translocated turfs providing an ideal substrate for orchids.
The excavator, with assistance from the ecologist, undertook the translocation of turfs and host plants one bucket at a time with materials being transported to the receptor sites in the excavator bucket to minimize handling and disturbance. A turf cutter was not used because of the composition of the substrate, which was largely composed of brick rubble, shale and other coal-mining waste.
Non-native trees within the ‘Plantation Receptor Site’ were removed and the topsoil stripped to expose the underlying colliery waste. This was sown with a species-rich grassland seed mix to provide habitat for dingy skipper adults. The site was further improved by the creation of six butterfly banks designed by Mike Slater of Butterfly Conservation (see above). ‘Dingy skipper turfs’ were placed onto the south facing side of the butterfly banks. Parts of the receptor sites were left untouched to enable the natural colonisation of orchids. Orchids and grassland translocated to the ‘Railway Receptor Site’ can be seen above. This area is being managed to maintain the botanical interest with annual cutting of the grassland.
A survey, undertaken in June 2014, found 29 dingy skipper eggs in the Phase 1 receptor site confirming that breeding is occurring. A count of the translocated orchid populations identified a slight decrease (10%) in the number of common spotted orchid spikes and doubling of the number of bee orchid spikes. This summer has seen the completion of the translocation works. Ongoing work will include monitoring for the dingy skipper, the removal of weeds and the management of the grassland for this species.