Fauna and temporal dynamics of dung beetles of the Fujinita-yama pasture [Japan], a long-term ecological research site

Dung beetle fauna was surveyed on a Zoysia japonica pasture in the Fujinita-Yama long-term ecological research site of National Institute of Livestock and Grassland Science at Nasu (NILGS-Fujinita) once a month during grazing period of May-October from 1999 to 2001 and 2003 to 2005 using a dung-baited basket trap. Dung beetle fauna and its temporal dynamics of the Fujinita-Yama pasture were characterized by comparing those to those of two neighbor pastures (within a distance of 3 km), the west pasture of NILGS (NILGS-West) and the south pasture of Jiyuu-Gakuen farm (Jiyuu-South). Eighteen species of dung beetles were collected, representing two Geotrupinae, six Scarabaienae, and 10 Aphodiinae species. Species richness of the NILGS-Fujinita fauna as estimated by Chao 2 was 18.4, significantly larger than that the 11.1 of Jiyuu-South. Species diversity (Shannon-Wiener's H ') of the NILGS-Fujinita fauna was significantly larger than those of NILGS-West and Jiyuu-South. The Dwellers/Tunnelers ratio based on species number was not significantly deviated from one. Similarity analysis among the faunae of the pastures by the Morishita-Horn index indicated that the dung beetle community structure of NILGS-Fujinita was different from those of NILGS-West and Jiyuu-South. The results suggested that the NILGS-Fujinita pasture was of conservation value for dung beetle diversity. Seasonal change in number of dung beetles in the NILGS-Fujinita pasture had two patterns over six years: a population increase from spring to summer followed by a decline to a low number by October; a decrease in number in midsummer followed by an increase until October. The seasonal changes in insect number of the NILGS-Fujinita pasture highly correlated with those of the other two pastures, representing a pattern that was common in the local dung beetle communities. The population dynamics of NILGS-Fujinita fauna during six years was stable. The dung beetles that were generally abundant in number might contribute to effective decomposition of cattle dung and thereby nutrients cycling in the NILGS-Fujinita pasture.