Zonation of soil‐dwelling invertebrates on a natural sandy beach, Tottori, western Japan

Abstract Sandy beaches are a globally threatened habitat, and endemic taxa are at risk of extinction. The soil‐dwelling fauna of natural sandy beaches in Japan is poorly known. We deployed 60 pitfall traps along ten transects from the high tideline to a coastal pine forest, on a natural sandy beach in Tottori during the summer. Traps caught 5,923 invertebrates belonging to 16 taxonomic groups, dominated by Coleoptera and Orthoptera. Zonation patterns of soil‐dwelling invertebrates are described at high (order or class) and low (species of Coleoptera) taxonomic levels using nonmetric multidimensional scaling and nonhierarchical clustering. At the high taxonomic level, invertebrates formed three groups of taxa extending from the tideline to the coastal forest. Tidal habitat was characterized by crustaceans (Amphipoda and Decapoda) and that of the forest edge by common forest soil‐dwelling taxa (e.g. Oligochaeta, Diplopoda, Isopoda). Vegetated dunes were characterized by taxa in the insect orders Dermaptera, Orthoptera, Hemiptera and Coleoptera. Two distinct groups of Coleoptera taxa were apparent: at the tideline, and at the dune–forest edge; tideline Coleoptera were characterized by Idisia ornata Pascoe, 1866, Hypocaccus varians varians (Schmidt, 1890), Eopachylopus ripae (Lewis, 1885), Suzukielater babai (Kishi & Ôhira, 1956), Phaleria atriceps (Lewis, 1894), and dune–forest edge Coleoptera by Phelopatrum scaphoides (Marseul, 1876), Craspedonotus tibialis Schaum, 1863, Paracardiophorus sequens sequens (Candèze, 1873), Meristhus niponensis Lewis, 1894, Scarites sulcatus sulcatus Olivier, 1795. Given the naturalness of the study site, we consider the distributions of taxa in this region to be characteristic of undisturbed sandy beaches in Japan.