Characterisation of Dung Beetle Assemblages Across a Wide Range of Forests in Japan

ABSTRACT Aim Dung beetles perform key ecosystem functions in forests; however, their assemblage structure in temperate Asia is not well understood. This study investigated dung beetle assemblages across 18 forests in Japan to identify their patterns and the environmental variables influencing them. Location Japan. Taxon Forest dung beetles (Geotrupidae, Scarabaeidae). Methods We surveyed dung beetle assemblages in 18 forests spanning broad climatic and environmental gradients. Taxonomic metrics included species richness, abundance, and species composition; functional metrics included the community‐weighted mean (CWM) body mass and functional dispersion (FDis) of body length and mass. Environmental variables included mean annual temperature (MAT), mean annual precipitation, soil properties, plant traits and sika deer presence. Results Generalised linear model analyses showed that MAT had a significant influence, with colder sites dominated by the large‐bodied Phelotrupes laevistriatus , resulting in higher CWM body mass. Soil pH was negatively associated with dung beetle abundance, and deer presence tended to increase abundance, although effects varied among sites. FDis of dung beetles showed no significant associations with environmental variables, and plant traits were unrelated to any dung beetle metrics. Species composition also varied with MAT, soil pH and deer presence. Main Conclusion Climate, soil conditions, and deer presence are important factors shaping dung beetle assemblages in Japanese forests. These factors, together with future climate warming, may influence the assemblage composition and the functional roles of dung beetles in dung decomposition.