Effects of forest-floor alteration due to high sika deer density on soil animal communities in early summer at Oku-Nikko, central Japan
2015
Tsurumi, K. ((Tokyo University of Agriculture and Technology (Japan). United Graduate School of Agricultural Science), (Tochigi Prefectural Utsunomiya Commercial High School (Japan))) | Okuda, K. | Koganezawa, M.
We aimed to assess the effects of forest-floor alteration caused by deer on soil animals. We examined the effects of deer density on forest-floor alteration and the relationship between the composition of soil animal communities and the forest-floor conditions in 3 areas (8 plots/area) with different deer densities in Oku-Nikko, Japan. Soil compaction increased and the thickness and dry weight of the Asub(0) layer and the void index decreased significantly with an increase in deer density, suggesting that deer density contributes to forest-floor alteration. We used TWINSPAN to divide 24 plots into groups A (high deer density) and B (low deer density) and 17 soil animal groups into groups 1-4. Predaceous myriapods and mesofauna that inhabit soil voids tended to belong to groups 1-3; and they were observed mostly in group B plots. Phytophagous dipterous insects and staphylinids that showed resistance to soil disturbance tended to belong to group 4; and they were found equally in group A and group B plots. Discriminant analysis indicated that the plot classification by TWINSPAN could be interpreted according to the thickness of the Asub(0) layer and the void index. These results indicate that forest-floor alteration (decreasing in the void index and thickness of the Asub(0) layer) because of high deer density may contribute to changes in the composition of soil animal communities.
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