Overview
BSG Ecology undertook a desk-based review to identify areas in the Upper Cynon Valley which had the potential to support marsh fritillary butterfly. These areas were then accessed and surveyed, habitat condition assessed, and practical advice provided on their management. This has enabled Natural Resources Wales to understand more about the current and potential role of these sites in increasing the resilience of the internationally important marsh fritillary metapopulation of the area.
Challenge
The Upper Cynon Valley, Rhondda Cynon Taf, is an internationally important area for marsh fritillary butterfly Euphydryas aurinia. A network of protected sites, including Blaen Cynon Special Area of Conservation and several Sites of Special Scientific Interest have been designated to conserve the species.
Natural Resources Wales (NRW) required information on habitat quality for marsh fritillary within the wider landscape. The purpose of the commission was to understand the likely current and potential contribution of land outside of the designated areas to maintaining the resilience of the marsh fritillary metapopulation. The results were to be used to inform management decisions on the protected sites and advice to landowners on land management in the wider area respectively.
The challenge was to select and access sites for survey, assess their condition in a standardized manner, and to provide practical land management advice that would benefit marsh fritillary if implemented.
Solution
A desk-based study was initially completed. This involved the use of existing population and habitat data alongside aerial imagery to prioritize sites for marsh fritillary survey. Sites prioritised included apparently suitable habitat for which there was no data on marsh fritillary, where data were historical, or where aerial imagery indicated an apparent change in land use or habitat condition since previous work had been done / the species had been recorded.
The NRW team assisted with the process of obtaining access permissions to the sites identified during the desk study. These were then surveyed using the methods and condition categories described by Fowles & Smith (2006) to characterise the habitats present. Key indicators of a good condition grassland for marsh fritillary are the presence of the larval foodplant, devil’s bit scabious (Succisa pratensis), variable vegetation height that ranges from 12 cm to 25 cm, and low levels of scrub species.
The results of the surveys were digitised using QGIS and Arc GIS software. Geo-referenced copies of land access information, survey details, habitat categories and field notes were provided as GIS shapefiles to allow their ready integration to ongoing or future projects, which should avoid the repetition of desk-based activities. A short factual report detailing the results of the surveys and providing recommendations for future achievable land management changes (based on conversations with landowners where relevant) was also provided.
Outcome
The outcome of the work is that NRW now understand more about habitat quality for marsh fritillary in the Upper Cynon valley. The results of the work will help inform future funding allocation and decision making aimed at improving the resilience of the internationally important population.
Testimonial
“This was a valuable project that contributes towards our understanding of the Marsh fritillary habitat availability in the landscape allowing us to make more informed management decisions on the protected sites in the area. Rachel was great to work with, always quick to respond and kept us up to date on progress throughout the project. The report and ArcGIS outputs are clear and informative.”
Iona Graham, Natura 2000 Sustainable Management Adviser
References
Fowles, A.P., Smith, R.G. (2006) Mapping the Habitat Quality of Patch Networks for the Marsh Fritillary Euphydryas aurinia (Rottemburg, 1775) (Lepidoptera, Nymphalidae) in Wales. J Insect Conserv 10, 161–177