岩手県雫石町の積雪期において積雪深および林相がイノシシの掘り返しを伴う採食場所選択に与える影響

抄録

To determine factors associated with the selection of rooting sites by wild boar (Sus scrofa) during winter snowfall, we conducted a snow-track census from January 2020 to February 2021 in Shizukuishi Town, Iwate Prefecture, Japan. We also collected and analyzed fresh boar feces during the study period. A generalized linear model was applied using the presence and absence of rooting tracks as the response variable; and forest type, snow depth on the survey date, and year as the explanatory variables. The best model, which used Akaike’s information criterion, included the forest type and snow depth on the survey date. The positive effect of broad-leaved mixed forest dominated by Quercus serrata and Q. crispula was statistically significant. In addition, acorns were frequently found and occupied 78.5% (mean proportion in total contents) of the sampled feces in 2020, when the snow depth range was 30–40 cm. Our findings indicate that wild boars prefer broad-leaved forests with less than 40 cm of snow depth, where acorns might be available. The positive effect of Cryptomeria japonica plantations and the negative effect of snow depth also showed statistical significance. These results indicate that wild boars selectively used evergreen coniferous forests to avoid deep snow and for easy rooting.