広島県宮島の常緑広葉樹林におけるシカの角研ぎ

The fraying by sika deer (Cervus nippon) in an evergreen broadleaf forest in Miyajima Island, Hiroshima, Japan, was studied. The proportion of trees frayed by deer to the total trees sampled (N = 1209) was 8.1%. Our data suggest that sika deer performed fraying on trees irrespective of diameter at breast height. We found that of the 29 tree species examined, 16 were frayed. Cleyera japonica had a significantly higher proportion of trees frayed by sika deer than the average overall proportion, suggesting that the species attracts sika deer for fraying. By contrast, sika deer significantly avoided Pinus densiflora, Lyonia ovalifolia var. elliptica, and Eurya japonica for fraying. Trees frayed were significantly spatially distributed aggregately. The fraying by deer occurred randomly, regardless of slope angles; sika deer can perform fraying even on very steep slopes. Trees on ridges avoided being frayed by deer, however. This may be explained by the presence of the trees that were less favored for sika-fraying performance (Pinus densiflora, Lyonia ovalifolia var. elliptica, and Eurya japonica), which were mainly distributed on ridge sites.