Mapping edge vegetation in connection to beech forest to locate potential habitats for red-listed beetles in Scania, Sweden

Abstract: The number of species classified as red-listed has increased by 11% between 2015 and 2020, with beetles and butterflies being especially affected. Among these are the vulnerable longhorned beetle (Stictoleptura scutellata) and the endangered false blister beetle (Ischnomera sanguinicollis). Forty percent of all known species in Sweden are dependent on hostplants, indicating the value in mapping potential habitats, including food sources for those species. Both Stictoleptura scutellata and Ischnomera sanguinicollis are dependent on dead wood from beech (Fagus sylvatica) for sheltered housing and flowering bushes in close proximity (e.g. edge vegetation) for pollen and nectar. The management technique in beech forest used in the mid-1800s and early 1900s have resulted in homogenous beech forests, lacking dead wood, old trees and tree structures such as cracks, cavities and torn branches (Maser & Trappe, 1984; Nilsson & Baranowski, 1995; Serup, 2005). These structures are vital habitat for many associated species, including Stictoleptura scutellate and Ischnomera sanguinicollis (Serup, 2005; Siitonen, 2001). Eight Natura 2000 classified beech forests (Asperulo-Fagetum and Luzulo-Fagetum types) were visited, with the forest edge being closely analysed and mapped using a Garmin GPSMAP 64 and ArcGIS Pro. Both edges with existing edge vegetation and areas suitable for plantation of edge vegetation were of interest and shown in maps overlying orthophotos of each area. Additional work was done on developing a method suitable for finding areas remotely suitable for plantation of edge vegetation. All areas visited included some form of edge vegetation, although many areas lacked the space or environment for plantations of more flowering bushes along the edge of the Natura 2000 classified beech forests. Suggestions of plantations of edges was made for all areas, although not always along beech forest edges, as edge vegetation can benefit other species as well, not only Stictoleptura scutellata and Ischnomera sanguinicollis.