表日光に生息するシカの食性の季節性

抄録

Food habits of the sika deer Cervus nippon were investigated in Omote-Nikko, Tochigi Prefecture from 1971 to 1973.
Eighty-two species eaten by the animals were recorded; 57 species of them were trees, 24 species were herbs, and one species was fungus.
Sasa nipponica was grazed all the year round as most important basic food plant both in quantity and in quality especially in winter when food plants were scarce. Carex sp. was also eaten throughout the year but in small quantity, and barks of Larix leptoleps, Pinus densiflora and Salix bakko also served as winter foods.
In May, buds and leaves of different plant species appeared successively. Deer grazed and browsed such plants one after another. Thus within a short period, many plants were recorded as deer food.
From June to August, 51 species were grazed and browsed, with strong preference of leaves and twigs of Hydrangea paniculata, Weigela decola and Stephanandra incisa. Grazing of herbs such as Leucosceptrum japonicum and Eupatrium chinense var. sachalinense was heavier than the browsing of tree leaves. One species of Agaricaceae was also eaten.
In September and October, leaves of Leucosceptrum japonicum, Eupatrium chinense var. sachalinense, Weigera decora and Clethra barbinervis were abundantly eaten. On the other hand, browsing of Sasa nipponica decreased. The leaves of L. japonicum and E. chinense var. sachalinense withered by the frost were not grazed. The analysis of the stomach contents showed that the acorns of Quercus mongolica var. grosseserrata and the fruits of Malus tshonoskii were also fed in this season.
In November and December, Sasa nipponica got abundantly grazed again. Most of the food plant species in this season were those commonly found in winter.