Community structure of saproxylic arthropods in urban fragmented forests and large-scale forests in a warm-temperate zone of East Asia

Saproxylic arthropods play an essential role in the detritus food chains of forest ecosystems by contributing to wood decomposition and nutrient cycling. However,little is known about the effects of urbanization on saproxylic arthropod communities. This study examined saproxylic arthropod communities in various landscapes, ranging from large to fragmented urban forests, and compared the structure and composition of these communities. The results showed that communities could be classified into three types based on species composition and that arthropod community types were correlated with forest size. The fragmented urban forest community contained a large number of individuals of a few facultative saproxylic species, whereas many obligate saproxylic species were present in the large forest community. Rarefaction curves based on the cumulative number of individuals revealed that fragmented urban forest communities had significantly lower species richness than large forested area communities. However, this difference was not significant when the curve was based on the cumulative wood volume. Therefore, large forests must be protected to conserve the overall diversity of saproxylic arthropods. However, the stag beetle, Dorcus rectus, was found to prefer urban fragmented forests over large-scale forests. As this species is popular among Japanese children, it is suitable for encouraging urban children to engage with natural ecosystems.