Relationships between browsing on dwarf bamboo (Sasa nip- ponica) by sika deer and the structure of ground beetle (Coleoptera: Carabidae) assemblage

Abstract

An overabundance of Sika deer (Cervus nippon) at Mt. Odaigahara, in west-central Japan has necessitated the introduction of exclusion fences to protect forest decline from excessive feeding damage. However, the effect of these exclusion fences on the biodiversity of arthropods within the protected areas has not been investigated. In this study we examined the relationships between the volume of dwarf bamboo (Sasa nipponica) , the major forage for the deer, on associated with browsing by deer and the structure of ground beetle assemblage. Both inside and outside of the exclusion fences, pitfall traps were setup in plots that had been assigned treatments of either no treatment (control) or artificial clipping of dwarf bamboo. Ground sticky traps were also set up in each plot to sample the abundance of small animals as the diet of ground beetles. Bamboo volume did not reltate to abundance, species richness, or diversity of the ground beetle assemblage. The abundance of the most dominant beetle species, Leptocarabus kumagaii, increased positively in response to both bamboo volume and the abundance of Orthopterans. The second most dominant species, Pterostichus fujitai, did not relate to bamboo volume, but decreased in abundance in relative to the propo- tions of open canopy. The third most species, Pterostichus microcephalus, decreased in abundance relative to bamboo volume, but increased positively in response to the abundance of Collembolans, Dipterans, and Hymenopterans. These results suggested that reduction of bamboo volume by browsing of deer did not affect the diversity of ground beetle aseemblage but affected its structure.