Changes in species, functional, and phylogenetic diversity of Aculeata communities along elevational gradients in the Kyushu Central Mountains of the Japanese archipelago

Climate change can degrade a community of Aculeata bees and wasps with important ecosystem roles, such as pollination and predation. In this study, we evaluated patterns in the species, functional, and phylogenetic diversity (PD) of Aculeata communities along elevational gradients in Miyazaki Prefecture, south of the Japanese archipelago. We used yellow pan traps to collect Aculeata at 200–1600 m above sea level for three seasons. We tested five functional traits (body size, trophic level, feeding guild, flight duration, and elevational range) and horizontal distribution of the species. The species diversity (SD) increased with increasing elevation. Body size, trophic level, and distribution diversity increased with increasing elevation. The community-weighted mean trophic level and flight duration decreased with increasing elevation. PD increased with increasing elevation. The number of northern species increased with increasing elevation. Trophic structure and high seasonal segregation by shortening flight duration should promote high SD at high elevation. The results of PD suggest that geographical barriers preventing the southern species migration decreased SD at low elevations. Community degradation in the lowlands can occur with geographical barriers that limit north–south migration. We show that evaluations of functional traits and phylogeny can reveal the mechanisms underlying community assembly at our sites, where both environmental and geographical conditions affect community assembly.