Elater ferrugineus or commonly known as the red click beetle is Sweden's second largest click beetle (17-24 mm). This beetle is one of the species that are associated with wood mould of hollow deciduous trees. Its main habitat in Sweden is oaks but also can be found in other tree species such as beech and elm. The populations of this species are affected by the fragmentation of its habitat and therefore they are classified as vulnerable by the Swedish Red list.

A total of 99 traps were placed systematically in a grid of 40 km × 40 km area in the province of Östergötland , Sweden. Additional strategic sampling in two areas: a) 78 traps within the study area (40 km x 40 km) and b) 47 traps in the entire Östergötland were used as validation data sets. 

The beetles were collected using a non-destructive pheromone-based trapping method, allowing the specimen to be released alive and marked with unique numbers after every catch. Traps were emptied every third day. 

Database on deciduous trees in Östergötland were used to calculate tree densities at various spatial scales and related with the occurrence of the beetles. Deciduous tree species that were included in this study are listed in the table below:

The scales where tree density best explained beetle occurence were then used in predicting the beetle’s potential distribution.