Saproxylic beetle assemblages exhibit distinct seasonal patterns across different decay classes of dead wood in a mixed temperate forest

Abstract Saproxylic organisms play a pivotal role in the decomposition of woody materials, profoundly impacting nutrient cycling within forest ecosystems. With their rich biodiversity and diverse ecological functions, saproxylic species provide unique ecological services and interactions that are closely linked to specific dead wood types. Given the distinctive roles and diversity of saproxylic beetles, forest loss and management practices that reduce dead wood amount and quality pose a risk of greater biodiversity loss. This highlights the critical need for comprehensive research into saproxylic beetle diversity and community structures from various perspectives to support sustainable forest management strategies. We sampled 60 Quercus logs in a temperate mixed forest during both winter and summer, and reared saproxylic beetles using emergence traps. Consequently, we collected a total of 1793 saproxylic beetles from 27 families and 75 species across three decay classes. Season was a key environmental variable, clearly distinguishing saproxylic beetle assemblages between winter and summer. While decay class did not clearly differentiate the beetle assemblages in summer, it distinctly separated the assemblages in winter. Our findings indicate that saproxylic beetles are influenced by changing resource availability and microclimate, driven by environmental variables such as season. This variability reveals the overlooked biodiversity potential, emphasizing the need for continuous and comprehensive research to achieve conservation goals and improve understanding of saproxylic organisms.