草兔对黄土高原主要造林树种的危害特征

Harmful Characteristics of Lepus capensis to Major Afforestation Tree Species in the Loess Plateau

为了减轻草兔(Lepus capensis)对新造幼林的危害,选择适宜的造林树种和苗龄,通过网室模拟试验研究与观察,对油松(Pinus tabulaeformis)、侧柏(Platycladus orientalis)、刺槐(Robinia pseudoacacia)、山桃(Prunus davidiana)、山杏(Prunus sibirica)、五角枫(Acer mono Maxim.)等18个造林树种遭受草兔危害的特征进行了研究。结果表明,草兔危害程度与苗龄、树种和树种组成密切相关。3年生油松和侧柏、4年生五角枫危害较轻,4年生山桃和5年生刺槐不受危害;草兔对四倍体刺槐、刺槐和山杏的危害十分严重,被害率在90%以上;在油松或山桃造林中,适当栽植刺槐或山杏等草兔喜食树种苗木,能明显减轻草兔对油松、山桃等目的树种的危害。草兔对苗木的危害程度和表面形态因树种不同而异,对油松、侧柏以咬断主干、枝叶为主;对山杏、刺槐等则以取食树叶、啃食茎干树皮为主,啃食区域则呈现块状、带状分布。观察发现,草兔对林木不同器官的选择取食,具有一定的顺序性,通常先取食叶片,然后啃食树皮。

An experiment was conducted to study the harmful characteristics of cape hares（Lepus capensis） to 18 tree species,such as Pinus tabulaeformis,Platycladus orientalis,Robinia pseudoacacia,Prunus davidiana and Prunus sibirica,in order to alleviate the damage to newly planted tree species subjected to cape hares in the Loess Plateau through artificial feeding and indoor observation.Results show that there are close relationships between damage degree and seedling age,tree species and composition of tree species.The damages to 3-year-old P.tabulaeformis and P.orientalis as well as 4-year-old Acer mono caused by cape hares are the slightest,and even no damage was found to 4-year-old P.davidiana and 5-year-old R.pseudoacacia of different seedling ages.The species of tetraploid R.pseudoacacia,R.pseudoacacia and P.sibirica are most easily damaged by cape hares,and the damage rates are over 90%.The damage by cape hares to major species of P.tabulaeformis and P.davidiana could be decreased by mixing with species of R.pseudoacacia or P.sibirica during planting,to which cape hares give more preference.The damage degree and morphological characteristics of seedlings damaged by cape hares vary with species.For P.tabulaeformis and P.orientalis,the stems,branches and leaves of seedlings are mostly snapped off by cape hares;for R.pseudoacacia and P.sibirica,the cape hares feed on the leaves and stem bark of seedlings.The damaged areas of bark are usually in patches or zones.It is found that the cape hares tend to feed on leaves first,and then on stem bark.